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diff --git a/gcc/ada/gnat_ugn.texi b/gcc/ada/gnat_ugn.texi index 17f2414..87becc74 100644 --- a/gcc/ada/gnat_ugn.texi +++ b/gcc/ada/gnat_ugn.texi @@ -1,831 +1,1253 @@ - \input texinfo @c -*-texinfo-*- @c %**start of header - -@c oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo -@c o -@c GNAT DOCUMENTATION o -@c o -@c G N A T _ U G N o -@c o -@c Copyright (C) 1992-2015, Free Software Foundation, Inc. o -@c o -@c oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo - @setfilename gnat_ugn.info +@documentencoding UTF-8 +@ifinfo +@*Generated by Sphinx 1.2.2.@* +@end ifinfo +@settitle GNAT User's Guide for Native Platforms +@defindex ge +@paragraphindent 0 +@exampleindent 4 +@finalout +@dircategory +@direntry +* gnat_ugn: (gnat_ugn.info). gnat_ugn +@end direntry + +@definfoenclose strong,`,' +@definfoenclose emph,`,' +@c %**end of header @copying -Copyright @copyright{} 1995-2015 Free Software Foundation, -Inc. +@quotation +GNAT User's Guide for Native Platforms , February 20, 2015 + +AdaCore + +Copyright @copyright{} 2008-2015, Free Software Foundation +@end quotation + +@end copying + +@titlepage +@title GNAT User's Guide for Native Platforms +@insertcopying +@end titlepage +@contents + +@c %** start of user preamble + +@c %** end of user preamble + +@ifnottex +@node Top +@top GNAT User's Guide for Native Platforms +@insertcopying +@end ifnottex + +@c %**start of body +@anchor{gnat_ugn doc}@anchor{0} +@emph{GNAT, The GNU Ada Development Environment} + + +@include gcc-common.texi +GCC version @value{version-GCC}@* +AdaCore Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no -Invariant Sections, with no Front-Cover Texts and with no Back-Cover -Texts. A copy of the license is included in the section entitled -``GNU Free Documentation License''. -@end copying +Invariant Sections, with the Front-Cover Texts being +"GNAT User's Guide for Native Platforms", +and with no Back-Cover Texts. A copy of the license is +included in the section entitled @ref{1,,GNU Free Documentation License}. -@c oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo -@c -@c GNAT_UGN Style Guide -@c -@c 1. Always put a @noindent on the line before the first paragraph -@c after any of these commands: -@c -@c @chapter -@c @section -@c @subsection -@c @subsubsection -@c @subsubsubsection -@c -@c @end smallexample -@c @end itemize -@c @end enumerate -@c -@c 2. DO NOT use @example. Use @smallexample instead. -@c a) DO NOT use highlighting commands (@b{}, @i{}) inside an @smallexample -@c context. These can interfere with the readability of the texi -@c source file. Instead, use one of the following annotated -@c @smallexample commands, and preprocess the texi file with the -@c ada2texi tool (which generates appropriate highlighting): -@c @smallexample @c ada -@c @smallexample @c adanocomment -@c @smallexample @c projectfile -@c b) The "@c ada" markup will result in boldface for reserved words -@c and italics for comments -@c c) The "@c adanocomment" markup will result only in boldface for -@c reserved words (comments are left alone) -@c d) The "@c projectfile" markup is like "@c ada" except that the set -@c of reserved words include the new reserved words for project files -@c -@c 3. Each @chapter, @section, @subsection, @subsubsection, etc. -@c command must be preceded by two empty lines -@c -@c 4. The @item command should be on a line of its own if it is in an -@c @itemize or @enumerate command. -@c -@c 5. When talking about ALI files use "ALI" (all uppercase), not "Ali" -@c or "ali". -@c -@c 6. DO NOT put trailing spaces at the end of a line. Such spaces will -@c cause the document build to fail. -@c -@c 7. DO NOT use @cartouche for examples that are longer than around 10 lines. -@c This command inhibits page breaks, so long examples in a @cartouche can -@c lead to large, ugly patches of empty space on a page. -@c -@c oooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo - -@set NOW January 2007 -@c This flag is used where the text refers to conditions that exist when the -@c text was entered into the document but which may change over time. -@c Update the setting for the flag, and (if necessary) the text surrounding, -@c the references to the flag, on future doc revisions: -@c search for @value{NOW}. - -@set FSFEDITION -@set EDITION GNAT - -@set PLATFORM - -@c @ovar(ARG) -@c ---------- -@c The ARG is an optional argument. To be used for macro arguments in -@c their documentation (@defmac). -@macro ovar{varname} -@r{[}@var{\varname\}@r{]}@c -@end macro -@c Status as of November 2009: -@c Unfortunately texi2pdf and texi2html treat the trailing "@c" -@c differently, and faulty output is produced by one or the other -@c depending on whether the "@c" is present or absent. -@c As a result, the @ovar macro is not used, and all invocations -@c of the @ovar macro have been expanded inline. - - -@settitle @value{EDITION} User's Guide -@dircategory GNU Ada tools -@direntry -* @value{EDITION} User's Guide: (gnat_ugn). @value{PLATFORM} -@end direntry +@menu +* About This Guide:: +* Getting Started with GNAT:: +* The GNAT Compilation Model:: +* Building Executable Programs with GNAT:: +* GNAT Project Manager:: +* Tools Supporting Project Files:: +* GNAT Utility Programs:: +* GNAT and Program Execution:: +* Platform-Specific Information:: +* Example of Binder Output File:: +* Elaboration Order Handling in GNAT:: +* Inline Assembler:: +* GNU Free Documentation License:: +* Index:: + +@detailmenu + --- The Detailed Node Listing --- + +About This Guide + +* What This Guide Contains:: +* What You Should Know before Reading This Guide:: +* Related Information:: +* A Note to Readers of Previous Versions of the Manual:: +* Conventions:: + +Getting Started with GNAT + +* Running GNAT:: +* Running a Simple Ada Program:: +* Running a Program with Multiple Units:: +* Using the gnatmake Utility:: + +The GNAT Compilation Model + +* Source Representation:: +* Foreign Language Representation:: +* File Naming Topics and Utilities:: +* Configuration Pragmas:: +* Generating Object Files:: +* Source Dependencies:: +* The Ada Library Information Files:: +* Binding an Ada Program:: +* GNAT and Libraries:: +* Conditional Compilation:: +* Mixed Language Programming:: +* GNAT and Other Compilation Models:: +* Using GNAT Files with External Tools:: + +Foreign Language Representation -@include gcc-common.texi +* Latin-1:: +* Other 8-Bit Codes:: +* Wide_Character Encodings:: +* Wide_Wide_Character Encodings:: + +File Naming Topics and Utilities -@setchapternewpage odd -@syncodeindex fn cp -@c %**end of header +* File Naming Rules:: +* Using Other File Names:: +* Alternative File Naming Schemes:: +* Handling Arbitrary File Naming Conventions with gnatname:: +* File Name Krunching with gnatkr:: +* Renaming Files with gnatchop:: -@titlepage -@title @value{EDITION} User's Guide +Handling Arbitrary File Naming Conventions with gnatname -@sp 2 +* Arbitrary File Naming Conventions:: +* Running gnatname:: +* Switches for gnatname:: +* Examples of gnatname Usage:: -@subtitle GNAT, The GNU Ada Development Environment -@versionsubtitle -@author AdaCore +File Name Krunching with gnatkr -@page -@vskip 0pt plus 1filll +* About gnatkr:: +* Using gnatkr:: +* Krunching Method:: +* Examples of gnatkr Usage:: -@insertcopying +Renaming Files with gnatchop -@end titlepage +* Handling Files with Multiple Units:: +* Operating gnatchop in Compilation Mode:: +* Command Line for gnatchop:: +* Switches for gnatchop:: +* Examples of gnatchop Usage:: -@ifnottex -@node Top, About This Guide, (dir), (dir) -@top @value{EDITION} User's Guide +Configuration Pragmas -@noindent -@value{EDITION} User's Guide @value{PLATFORM} +* Handling of Configuration Pragmas:: +* The Configuration Pragmas Files:: -@noindent -GNAT, The GNU Ada Development Environment@* -GCC version @value{version-GCC}@* +GNAT and Libraries -@noindent -AdaCore@* +* Introduction to Libraries in GNAT:: +* General Ada Libraries:: +* Stand-alone Ada Libraries:: +* Rebuilding the GNAT Run-Time Library:: -@menu -* About This Guide:: -* Getting Started with GNAT:: -* The GNAT Compilation Model:: -* Compiling with gcc:: -* Binding with gnatbind:: -* Linking with gnatlink:: -* The GNAT Make Program gnatmake:: -* Improving Performance:: -* Renaming Files with gnatchop:: -* Configuration Pragmas:: -* Handling Arbitrary File Naming Conventions with gnatname:: -* GNAT Project Manager:: -* Tools Supporting Project Files:: -* The Cross-Referencing Tools gnatxref and gnatfind:: -@ifclear FSFEDITION -* The GNAT Pretty-Printer gnatpp:: -* The Ada-to-XML converter gnat2xml:: -* The GNAT Metrics Tool gnatmetric:: -@end ifclear -* File Name Krunching with gnatkr:: -* Preprocessing with gnatprep:: -* The GNAT Library Browser gnatls:: -* Cleaning Up with gnatclean:: -* GNAT and Libraries:: -* Using the GNU make Utility:: -* Memory Management Issues:: -* Stack Related Facilities:: -@ifclear FSFEDITION -* Verifying Properties with gnatcheck:: -* Creating Sample Bodies with gnatstub:: -* Creating Unit Tests with gnattest:: -@end ifclear -* Performing Dimensionality Analysis in GNAT:: -* Generating Ada Bindings for C and C++ headers:: -* Other Utility Programs:: -* Code Coverage and Profiling:: -* Running and Debugging Ada Programs:: -* Platform-Specific Information for the Run-Time Libraries:: -* Example of Binder Output File:: -* Elaboration Order Handling in GNAT:: -* Overflow Check Handling in GNAT:: -* Conditional Compilation:: -* Inline Assembler:: -* Writing Portable Fixed-Point Declarations:: -* Compatibility and Porting Guide:: -* Microsoft Windows Topics:: -* Mac OS Topics:: -* GNU Free Documentation License:: -* Index:: +General Ada Libraries + +* Building a library:: +* Installing a library:: +* Using a library:: + +Stand-alone Ada Libraries + +* Introduction to Stand-alone Libraries:: +* Building a Stand-alone Library:: +* Creating a Stand-alone Library to be used in a non-Ada context:: +* Restrictions in Stand-alone Libraries:: + +Conditional Compilation + +* Modeling Conditional Compilation in Ada:: +* Preprocessing with gnatprep:: +* Integrated Preprocessing:: + +Modeling Conditional Compilation in Ada + +* Use of Boolean Constants:: +* Debugging - A Special Case:: +* Conditionalizing Declarations:: +* Use of Alternative Implementations:: +* Preprocessing:: + +Preprocessing with gnatprep + +* Preprocessing Symbols:: +* Using gnatprep:: +* Switches for gnatprep:: +* Form of Definitions File:: +* Form of Input Text for gnatprep:: + +Mixed Language Programming + +* Interfacing to C:: +* Calling Conventions:: +* Building Mixed Ada and C++ Programs:: +* Generating Ada Bindings for C and C++ headers:: + +Building Mixed Ada and C++ Programs + +* Interfacing to C++:: +* Linking a Mixed C++ & Ada Program:: +* A Simple Example:: +* Interfacing with C++ constructors:: +* Interfacing with C++ at the Class Level:: + +Generating Ada Bindings for C and C++ headers + +* Running the binding generator:: +* Generating bindings for C++ headers:: +* Switches:: + +GNAT and Other Compilation Models + +* Comparison between GNAT and C/C++ Compilation Models:: +* Comparison between GNAT and Conventional Ada Library Models:: + +Using GNAT Files with External Tools + +* Using Other Utility Programs with GNAT:: +* The External Symbol Naming Scheme of GNAT:: + +Building Executable Programs with GNAT + +* Building with gnatmake:: +* Compiling with gcc:: +* Compiler Switches:: +* Binding with gnatbind:: +* Linking with gnatlink:: +* Using the GNU make Utility:: + +Building with gnatmake + +* Running gnatmake:: +* Switches for gnatmake:: +* Mode Switches for gnatmake:: +* Notes on the Command Line:: +* How gnatmake Works:: +* Examples of gnatmake Usage:: + +Compiling with gcc + +* Compiling Programs:: +* Search Paths and the Run-Time Library (RTL): Search Paths and the Run-Time Library RTL. +* Order of Compilation Issues:: +* Examples:: + +Compiler Switches + +* Alphabetical List of All Switches:: +* Output and Error Message Control:: +* Warning Message Control:: +* Debugging and Assertion Control:: +* Validity Checking:: +* Style Checking:: +* Run-Time Checks:: +* Using gcc for Syntax Checking:: +* Using gcc for Semantic Checking:: +* Compiling Different Versions of Ada:: +* Character Set Control:: +* File Naming Control:: +* Subprogram Inlining Control:: +* Auxiliary Output Control:: +* Debugging Control:: +* Exception Handling Control:: +* Units to Sources Mapping Files:: +* Code Generation Control:: + +Binding with gnatbind + +* Running gnatbind:: +* Switches for gnatbind:: +* Command-Line Access:: +* Search Paths for gnatbind:: +* Examples of gnatbind Usage:: + +Switches for gnatbind + +* Consistency-Checking Modes:: +* Binder Error Message Control:: +* Elaboration Control:: +* Output Control:: +* Dynamic Allocation Control:: +* Binding with Non-Ada Main Programs:: +* Binding Programs with No Main Subprogram:: + +Linking with gnatlink + +* Running gnatlink:: +* Switches for gnatlink:: + +Using the GNU make Utility + +* Using gnatmake in a Makefile:: +* Automatically Creating a List of Directories:: +* Generating the Command Line Switches:: +* Overcoming Command Line Length Limits:: + +GNAT Project Manager + +* Introduction:: +* Building With Projects:: +* Organizing Projects into Subsystems:: +* Scenarios in Projects:: +* Library Projects:: +* Project Extension:: +* Aggregate Projects:: +* Aggregate Library Projects:: +* Project File Reference:: + +Building With Projects + +* Source Files and Directories:: +* Duplicate Sources in Projects:: +* Object and Exec Directory:: +* Main Subprograms:: +* Tools Options in Project Files:: +* Compiling with Project Files:: +* Executable File Names:: +* Avoid Duplication With Variables:: +* Naming Schemes:: +* Installation:: +* Distributed support:: + +Organizing Projects into Subsystems + +* Project Dependencies:: +* Cyclic Project Dependencies:: +* Sharing Between Projects:: +* Global Attributes:: + +Library Projects + +* Building Libraries:: +* Using Library Projects:: +* Stand-alone Library Projects:: +* Installing a library with project files:: + +Project Extension + +* Project Hierarchy Extension:: + +Aggregate Projects + +* Building all main programs from a single project tree:: +* Building a set of projects with a single command:: +* Define a build environment:: +* Performance improvements in builder:: +* Syntax of aggregate projects:: +* package Builder in aggregate projects:: + +Aggregate Library Projects + +* Building aggregate library projects:: +* Syntax of aggregate library projects:: + +Project File Reference + +* Project Declaration:: +* Qualified Projects:: +* Declarations:: +* Packages:: +* Expressions:: +* External Values:: +* Typed String Declaration:: +* Variables:: +* Case Constructions:: +* Attributes:: + +Attributes + +* Project Level Attributes:: +* Package Binder Attributes:: +* Package Builder Attributes:: +* Package Clean Attributes:: +* Package Compiler Attributes:: +* Package Cross_Reference Attributes:: +* Package Finder Attributes:: +* Package gnatls Attributes:: +* Package IDE Attributes:: +* Package Install Attributes:: +* Package Linker Attributes:: +* Package Naming Attributes:: +* Package Remote Attributes:: +* Package Stack Attributes:: +* Package Synchronize Attributes:: + +Tools Supporting Project Files + +* gnatmake and Project Files:: +* The GNAT Driver and Project Files:: + +gnatmake and Project Files + +* Switches Related to Project Files:: +* Switches and Project Files:: +* Specifying Configuration Pragmas:: +* Project Files and Main Subprograms:: +* Library Project Files:: + +GNAT Utility Programs + +* The File Cleanup Utility gnatclean:: +* The GNAT Library Browser gnatls:: +* The Cross-Referencing Tools gnatxref and gnatfind:: +* The Ada to HTML Converter gnathtml:: + +The File Cleanup Utility gnatclean + +* Running gnatclean:: +* Switches for gnatclean:: + +The GNAT Library Browser gnatls + +* Running gnatls:: +* Switches for gnatls:: +* Example of gnatls Usage:: + +The Cross-Referencing Tools gnatxref and gnatfind + +* gnatxref Switches:: +* gnatfind Switches:: +* Project Files for gnatxref and gnatfind:: +* Regular Expressions in gnatfind and gnatxref:: +* Examples of gnatxref Usage:: +* Examples of gnatfind Usage:: + +Examples of gnatxref Usage + +* General Usage:: +* Using gnatxref with vi:: + +The Ada to HTML Converter gnathtml + +* Invoking gnathtml:: +* Installing gnathtml:: + +GNAT and Program Execution + +* Running and Debugging Ada Programs:: +* Code Coverage and Profiling:: +* Improving Performance:: +* Overflow Check Handling in GNAT:: +* Performing Dimensionality Analysis in GNAT:: +* Stack Related Facilities:: +* Memory Management Issues:: + +Running and Debugging Ada Programs + +* The GNAT Debugger GDB:: +* Running GDB:: +* Introduction to GDB Commands:: +* Using Ada Expressions:: +* Calling User-Defined Subprograms:: +* Using the next Command in a Function:: +* Stopping When Ada Exceptions Are Raised:: +* Ada Tasks:: +* Debugging Generic Units:: +* Remote Debugging with gdbserver:: +* GNAT Abnormal Termination or Failure to Terminate:: +* Naming Conventions for GNAT Source Files:: +* Getting Internal Debugging Information:: +* Stack Traceback:: + +Stack Traceback + +* Non-Symbolic Traceback:: +* Symbolic Traceback:: + +Code Coverage and Profiling + +* Code Coverage of Ada Programs with gcov:: +* Profiling an Ada Program with gprof:: + +Code Coverage of Ada Programs with gcov + +* Quick startup guide:: +* GNAT specifics:: + +Profiling an Ada Program with gprof + +* Compilation for profiling:: +* Program execution:: +* Running gprof:: +* Interpretation of profiling results:: + +Improving Performance + +* Performance Considerations:: +* Text_IO Suggestions:: +* Reducing Size of Executables with Unused Subprogram/Data Elimination:: + +Performance Considerations + +* Controlling Run-Time Checks:: +* Use of Restrictions:: +* Optimization Levels:: +* Debugging Optimized Code:: +* Inlining of Subprograms:: +* Floating_Point_Operations:: +* Vectorization of loops:: +* Other Optimization Switches:: +* Optimization and Strict Aliasing:: +* Aliased Variables and Optimization:: +* Atomic Variables and Optimization:: +* Passive Task Optimization:: + +Reducing Size of Executables with Unused Subprogram/Data Elimination + +* About unused subprogram/data elimination:: +* Compilation options:: +* Example of unused subprogram/data elimination:: + +Overflow Check Handling in GNAT + +* Background:: +* Overflow Checking Modes in GNAT:: +* Specifying the Desired Mode:: +* Default Settings:: +* Implementation Notes:: + +Stack Related Facilities + +* Stack Overflow Checking:: +* Static Stack Usage Analysis:: +* Dynamic Stack Usage Analysis:: + +Memory Management Issues + +* Some Useful Memory Pools:: +* The GNAT Debug Pool Facility:: + +Platform-Specific Information + +* Run-Time Libraries:: +* Specifying a Run-Time Library:: +* Microsoft Windows Topics:: +* Mac OS Topics:: + +Run-Time Libraries + +* Summary of Run-Time Configurations:: + +Specifying a Run-Time Library + +* Choosing the Scheduling Policy:: +* Solaris-Specific Considerations:: +* Solaris Threads Issues:: +* AIX-Specific Considerations:: + +Microsoft Windows Topics + +* Using GNAT on Windows:: +* Using a network installation of GNAT:: +* CONSOLE and WINDOWS subsystems:: +* Temporary Files:: +* Mixed-Language Programming on Windows:: + +Mixed-Language Programming on Windows + +* Windows Calling Conventions:: +* Introduction to Dynamic Link Libraries (DLLs): Introduction to Dynamic Link Libraries DLLs. +* Using DLLs with GNAT:: +* Building DLLs with GNAT Project files:: +* Building DLLs with GNAT:: +* Building DLLs with gnatdll:: +* Ada DLLs and Finalization:: +* Creating a Spec for Ada DLLs:: +* GNAT and Windows Resources:: +* Debugging a DLL:: +* Setting Stack Size from gnatlink:: +* Setting Heap Size from gnatlink:: + +Windows Calling Conventions + +* C Calling Convention:: +* Stdcall Calling Convention:: +* Win32 Calling Convention:: +* DLL Calling Convention:: + +Using DLLs with GNAT + +* Creating an Ada Spec for the DLL Services:: +* Creating an Import Library:: + +Building DLLs with gnatdll + +* Limitations When Using Ada DLLs from Ada:: +* Exporting Ada Entities:: +* Ada DLLs and Elaboration:: + +Creating a Spec for Ada DLLs + +* Creating the Definition File:: +* Using gnatdll:: + +GNAT and Windows Resources + +* Building Resources:: +* Compiling Resources:: +* Using Resources:: + +Debugging a DLL + +* Program and DLL Both Built with GCC/GNAT:: +* Program Built with Foreign Tools and DLL Built with GCC/GNAT:: + +Mac OS Topics + +* Codesigning the Debugger:: + +Elaboration Order Handling in GNAT + +* Elaboration Code:: +* Checking the Elaboration Order:: +* Controlling the Elaboration Order:: +* Controlling Elaboration in GNAT - Internal Calls:: +* Controlling Elaboration in GNAT - External Calls:: +* Default Behavior in GNAT - Ensuring Safety:: +* Treatment of Pragma Elaborate:: +* Elaboration Issues for Library Tasks:: +* Mixing Elaboration Models:: +* What to Do If the Default Elaboration Behavior Fails:: +* Elaboration for Indirect Calls:: +* Summary of Procedures for Elaboration Control:: +* Other Elaboration Order Considerations:: +* Determining the Chosen Elaboration Order:: + +Inline Assembler + +* Basic Assembler Syntax:: +* A Simple Example of Inline Assembler:: +* Output Variables in Inline Assembler:: +* Input Variables in Inline Assembler:: +* Inlining Inline Assembler Code:: +* Other Asm Functionality:: + +Other Asm Functionality + +* The Clobber Parameter:: +* The Volatile Parameter:: + +@end detailmenu @end menu -@end ifnottex -@node About This Guide -@unnumbered About This Guide +@node About This Guide,Getting Started with GNAT,Top,Top +@anchor{gnat_ugn/about_this_guide about-this-guide}@anchor{2}@anchor{gnat_ugn/about_this_guide doc}@anchor{3}@anchor{gnat_ugn/about_this_guide gnat-user-s-guide-for-native-platforms}@anchor{4}@anchor{gnat_ugn/about_this_guide id1}@anchor{5} +@chapter About This Guide + -@noindent -This guide describes the use of @value{EDITION}, + +This guide describes the use of GNAT, a compiler and software development toolset for the full Ada programming language. It documents the features of the compiler and tools, and explains how to use them to build Ada applications. -@value{EDITION} implements Ada 95, Ada 2005 and Ada 2012, and it may also be +GNAT implements Ada 95, Ada 2005 and Ada 2012, and it may also be invoked in Ada 83 compatibility mode. -By default, @value{EDITION} assumes Ada 2012, but you can override with a -compiler switch (@pxref{Compiling Different Versions of Ada}) +By default, GNAT assumes Ada 2012, but you can override with a +compiler switch (@ref{6,,Compiling Different Versions of Ada}) to explicitly specify the language version. -Throughout this manual, references to ``Ada'' without a year suffix +Throughout this manual, references to 'Ada' without a year suffix apply to all Ada 95/2005/2012 versions of the language. -@ifclear FSFEDITION -For ease of exposition, ``@value{EDITION}'' will be referred to simply as -``GNAT'' in the remainder of this document. -@end ifclear - - @menu -* What This Guide Contains:: -* What You Should Know before Reading This Guide:: -* Related Information:: -* Conventions:: +* What This Guide Contains:: +* What You Should Know before Reading This Guide:: +* Related Information:: +* A Note to Readers of Previous Versions of the Manual:: +* Conventions:: + @end menu -@node What This Guide Contains -@unnumberedsec What This Guide Contains +@node What This Guide Contains,What You Should Know before Reading This Guide,,About This Guide +@anchor{gnat_ugn/about_this_guide what-this-guide-contains}@anchor{7} +@section What This Guide Contains + -@noindent This guide contains the following chapters: -@itemize @bullet -@item -@ref{Getting Started with GNAT}, describes how to get started compiling + +@itemize * + +@item +@ref{8,,Getting Started with GNAT} describes how to get started compiling and running Ada programs with the GNAT Ada programming environment. -@item -@ref{The GNAT Compilation Model}, describes the compilation model used + +@item +@ref{9,,The GNAT Compilation Model} describes the compilation model used by GNAT. -@item -@ref{Compiling with gcc}, describes how to compile -Ada programs with @command{gcc}, the Ada compiler. +@item +@ref{a,,Building Executable Programs with GNAT} describes how to use the +main GNAT tools to build executable programs, and it also gives examples of +using the GNU make utility with GNAT. -@item -@ref{Binding with gnatbind}, describes how to -perform binding of Ada programs with @code{gnatbind}, the GNAT binding -utility. +@item +@ref{b,,GNAT Project Manager} describes how to use project files +to organize large projects. -@item -@ref{Linking with gnatlink}, -describes @command{gnatlink}, a -program that provides for linking using the GNAT run-time library to -construct a program. @command{gnatlink} can also incorporate foreign language -object units into the executable. +@item +@ref{c,,Tools Supporting Project Files} described how to use the project +facility in conjunction with various GNAT tools. -@item -@ref{The GNAT Make Program gnatmake}, describes @command{gnatmake}, a -utility that automatically determines the set of sources -needed by an Ada compilation unit, and executes the necessary compilations -binding and link. +@item +@ref{d,,GNAT Utility Programs} explains the various utility programs that +are included in the GNAT environment -@item -@ref{Improving Performance}, shows various techniques for making your -Ada program run faster or take less space and describes the effect of -the compiler's optimization switch. -It also describes -@ifclear FSFEDITION -the @command{gnatelim} tool and -@end ifclear -unused subprogram/data elimination. +@item +@ref{e,,GNAT and Program Execution} covers a number of topics related to +running, debugging, and tuning the performace of programs developed +with GNAT +@end itemize -@item -@ref{Renaming Files with gnatchop}, describes -@code{gnatchop}, a utility that allows you to preprocess a file that -contains Ada source code, and split it into one or more new files, one -for each compilation unit. +Appendices cover several additional topics: -@item -@ref{Configuration Pragmas}, describes the configuration pragmas -handled by GNAT. -@item -@ref{Handling Arbitrary File Naming Conventions with gnatname}, -shows how to override the default GNAT file naming conventions, -either for an individual unit or globally. +@itemize * -@item -@ref{GNAT Project Manager}, describes how to use project files -to organize large projects. +@item +@ref{f,,Platform-Specific Information} describes the different run-time +library implementations and also presents information on how to use +GNAT on several specific platforms -@item -@ref{The Cross-Referencing Tools gnatxref and gnatfind}, discusses -@code{gnatxref} and @code{gnatfind}, two tools that provide an easy -way to navigate through sources. +@item +@ref{10,,Example of Binder Output File} shows the source code for the binder +output file for a sample program. -@ifclear FSFEDITION -@item -@ref{The GNAT Pretty-Printer gnatpp}, shows how to produce a reformatted -version of an Ada source file with control over casing, indentation, -comment placement, and other elements of program presentation style. -@end ifclear +@item +@ref{11,,Elaboration Order Handling in GNAT} describes how GNAT helps +you deal with elaboration order issues. -@ifclear FSFEDITION -@item -@ref{The Ada-to-XML converter gnat2xml}, shows how to convert Ada -source code into XML. -@end ifclear +@item +@ref{12,,Inline Assembler} shows how to use the inline assembly facility +in an Ada program. +@end itemize -@ifclear FSFEDITION -@item -@ref{The GNAT Metrics Tool gnatmetric}, shows how to compute various -metrics for an Ada source file, such as the number of types and subprograms, -and assorted complexity measures. -@end ifclear +@node What You Should Know before Reading This Guide,Related Information,What This Guide Contains,About This Guide +@anchor{gnat_ugn/about_this_guide what-you-should-know-before-reading-this-guide}@anchor{13} +@section What You Should Know before Reading This Guide -@item -@ref{File Name Krunching with gnatkr}, describes the @code{gnatkr} -file name krunching utility, used to handle shortened -file names on operating systems with a limit on the length of names. -@item -@ref{Preprocessing with gnatprep}, describes @code{gnatprep}, a -preprocessor utility that allows a single source file to be used to -generate multiple or parameterized source files by means of macro -substitution. +@geindex Ada 95 Language Reference Manual -@item -@ref{The GNAT Library Browser gnatls}, describes @code{gnatls}, a -utility that displays information about compiled units, including dependences -on the corresponding sources files, and consistency of compilations. +@geindex Ada 2005 Language Reference Manual -@item -@ref{Cleaning Up with gnatclean}, describes @code{gnatclean}, a utility -to delete files that are produced by the compiler, binder and linker. +This guide assumes a basic familiarity with the Ada 95 language, as +described in the International Standard ANSI/ISO/IEC-8652:1995, January +1995. +It does not require knowledge of the features introduced by Ada 2005 +or Ada 2012. +Reference manuals for Ada 95, Ada 2005, and Ada 2012 are included in +the GNAT documentation package. -@item -@ref{GNAT and Libraries}, describes the process of creating and using -Libraries with GNAT. It also describes how to recompile the GNAT run-time -library. +@node Related Information,A Note to Readers of Previous Versions of the Manual,What You Should Know before Reading This Guide,About This Guide +@anchor{gnat_ugn/about_this_guide related-information}@anchor{14} +@section Related Information -@item -@ref{Using the GNU make Utility}, describes some techniques for using -the GNAT toolset in Makefiles. -@item -@ref{Memory Management Issues}, describes some useful predefined storage pools -and in particular the GNAT Debug Pool facility, which helps detect incorrect -memory references. -@ifclear FSFEDITION -It also describes @command{gnatmem}, a utility that monitors dynamic -allocation and deallocation and helps detect ``memory leaks''. -@end ifclear +For further information about Ada and related tools, please refer to the +following documents: -@item -@ref{Stack Related Facilities}, describes some useful tools associated with -stack checking and analysis. -@ifclear FSFEDITION -@item -@ref{Verifying Properties with gnatcheck}, discusses @code{gnatcheck}, -a utility that checks Ada code against a set of rules. +@itemize * -@item -@ref{Creating Sample Bodies with gnatstub}, discusses @code{gnatstub}, -a utility that generates empty but compilable bodies for library units. -@end ifclear +@item +@cite{Ada 95 Reference Manual}, @cite{Ada 2005 Reference Manual}, and +@cite{Ada 2012 Reference Manual}, which contain reference +material for the several revisions of the Ada language standard. -@ifclear FSFEDITION -@item -@ref{Creating Unit Tests with gnattest}, discusses @code{gnattest}, -a utility that generates unit testing templates for library units. -@end ifclear +@item +@cite{GNAT Reference_Manual}, which contains all reference material for the GNAT +implementation of Ada. -@item -@ref{Performing Dimensionality Analysis in GNAT}, describes the Ada 2012 -facilities used in GNAT to declare dimensioned objects, and to verify that -uses of these objects are consistent with their given physical dimensions -(so that meters cannot be assigned to kilograms, and so on). +@item +@cite{Using the GNAT Programming Studio}, which describes the GPS +Integrated Development Environment. -@item -@ref{Generating Ada Bindings for C and C++ headers}, describes how to -generate automatically Ada bindings from C and C++ headers. +@item +@cite{GNAT Programming Studio Tutorial}, which introduces the +main GPS features through examples. -@item -@ref{Other Utility Programs}, discusses several other GNAT utilities, -including @code{gnathtml}. +@item +@cite{Debugging with GDB}, +for all details on the use of the GNU source-level debugger. -@item -@ref{Code Coverage and Profiling}, describes how to perform a structural -coverage and profile the execution of Ada programs. +@item +@cite{GNU Emacs Manual}, +for full information on the extensible editor and programming +environment Emacs. +@end itemize -@item -@ref{Running and Debugging Ada Programs}, describes how to run and debug -Ada programs. +@node A Note to Readers of Previous Versions of the Manual,Conventions,Related Information,About This Guide +@anchor{gnat_ugn/about_this_guide a-note-to-readers-of-previous-versions-of-the-manual}@anchor{15} +@section A Note to Readers of Previous Versions of the Manual -@item -@ref{Platform-Specific Information for the Run-Time Libraries}, -describes the various run-time -libraries supported by GNAT on various platforms and explains how to -choose a particular library. +In early 2015 the GNAT manuals were transitioned to the +reStructuredText (rst) / Sphinx documentation generator technology. +During that process the @cite{GNAT User's Guide} was reorganized +so that related topics would be described together in the same chapter +or appendix. Here's a summary of the major changes realized in +the new document structure. -@item -@ref{Example of Binder Output File}, shows the source code for the binder -output file for a sample program. -@item -@ref{Elaboration Order Handling in GNAT}, describes how GNAT helps -you deal with elaboration order issues. +@itemize * -@item -@ref{Overflow Check Handling in GNAT}, describes how GNAT helps -you deal with arithmetic overflow issues. +@item +@ref{9,,The GNAT Compilation Model} has been extended so that it now covers +the following material: -@item -@ref{Conditional Compilation}, describes how to model conditional compilation, -both with Ada in general and with GNAT facilities in particular. -@item -@ref{Inline Assembler}, shows how to use the inline assembly facility -in an Ada program. +@itemize - -@item -@ref{Writing Portable Fixed-Point Declarations}, gives some guidance on -defining portable fixed-point types. +@item +The @cite{gnatname}, @cite{gnatkr}, and @cite{gnatchop} tools -@item -@ref{Compatibility and Porting Guide}, contains sections on compatibility -of GNAT with other Ada development environments (including Ada 83 systems), -to assist in porting code from those environments. +@item +@ref{16,,Configuration Pragmas} -@item -@ref{Microsoft Windows Topics}, presents information relevant to the -Microsoft Windows platform. +@item +@ref{17,,GNAT and Libraries} -@item -@ref{Mac OS Topics}, presents information relevant to Apple's OS X -platform. +@item +@ref{18,,Conditional Compilation} including @ref{19,,Preprocessing with gnatprep} +and @ref{1a,,Integrated Preprocessing} + +@item +@ref{1b,,Generating Ada Bindings for C and C++ headers} + +@item +@ref{1c,,Using GNAT Files with External Tools} @end itemize -@c ************************************************* -@node What You Should Know before Reading This Guide -@c ************************************************* -@unnumberedsec What You Should Know before Reading This Guide +@item +@ref{a,,Building Executable Programs with GNAT} is a new chapter consolidating +the following content: -@cindex Ada 95 Language Reference Manual -@cindex Ada 2005 Language Reference Manual -@noindent -This guide assumes a basic familiarity with the Ada 95 language, as -described in the International Standard ANSI/ISO/IEC-8652:1995, January -1995. -It does not require knowledge of the new features introduced by Ada 2005, -(officially known as ISO/IEC 8652:1995 with Technical Corrigendum 1 -and Amendment 1). -Both reference manuals are included in the GNAT documentation -package. -@node Related Information -@unnumberedsec Related Information +@itemize - -@noindent -For further information about related tools, refer to the following -documents: +@item +@ref{1d,,Building with gnatmake} -@itemize @bullet -@item -@xref{Top, GNAT Reference Manual, About This Guide, gnat_rm, GNAT -Reference Manual}, which contains all reference material for the GNAT -implementation of Ada. +@item +@ref{1e,,Compiling with gcc} -@item -@cite{Using the GNAT Programming Studio}, which describes the GPS -Integrated Development Environment. +@item +@ref{1f,,Binding with gnatbind} -@item -@cite{GNAT Programming Studio Tutorial}, which introduces the -main GPS features through examples. +@item +@ref{20,,Linking with gnatlink} -@item -@cite{Ada 95 Reference Manual}, which contains reference -material for the Ada 95 programming language. +@item +@ref{21,,Using the GNU make Utility} +@end itemize -@item -@cite{Ada 2005 Reference Manual}, which contains reference -material for the Ada 2005 programming language. +@item +@ref{d,,GNAT Utility Programs} is a new chapter consolidating the information about several +GNAT tools: -@item -@xref{Top,, Debugging with GDB, gdb, Debugging with GDB}, -for all details on the use of the GNU source-level debugger. -@item -@xref{Top,, The extensible self-documenting text editor, emacs, -GNU Emacs Manual}, -for full information on the extensible editor and programming -environment Emacs. +@itemize - + +@item +@ref{22,,The File Cleanup Utility gnatclean} + +@item +@ref{23,,The GNAT Library Browser gnatls} + +@item +@ref{24,,The Cross-Referencing Tools gnatxref and gnatfind} + +@item +@ref{25,,The Ada to HTML Converter gnathtml} +@end itemize + +@item +@ref{e,,GNAT and Program Execution} is a new chapter consolidating the following: + + +@itemize - + +@item +@ref{26,,Running and Debugging Ada Programs} + +@item +@ref{27,,Code Coverage and Profiling} + +@item +@ref{28,,Improving Performance} + +@item +@ref{29,,Overflow Check Handling in GNAT} + +@item +@ref{2a,,Performing Dimensionality Analysis in GNAT} + +@item +@ref{2b,,Stack Related Facilities} + +@item +@ref{2c,,Memory Management Issues} @end itemize -@c ************** -@node Conventions -@unnumberedsec Conventions -@cindex Conventions -@cindex Typographical conventions +@item +@ref{f,,Platform-Specific Information} is a new appendix consolidating the following: + + +@itemize - + +@item +@ref{2d,,Run-Time Libraries} + +@item +@ref{2e,,Microsoft Windows Topics} + +@item +@ref{2f,,Mac OS Topics} +@end itemize + +@item +The @cite{Compatibility and Porting Guide} appendix has been moved to the +@cite{GNAT Reference Manual}. It now includes a section +@cite{Writing Portable Fixed-Point Declarations} which was previously +a separate chapter in the @cite{GNAT User's Guide}. +@end itemize + +@node Conventions,,A Note to Readers of Previous Versions of the Manual,About This Guide +@anchor{gnat_ugn/about_this_guide conventions}@anchor{30} +@section Conventions + + +@geindex Conventions +@geindex typographical + +@geindex Typographical conventions -@noindent Following are examples of the typographical and graphic conventions used in this guide: -@itemize @bullet -@item -@code{Functions}, @command{utility program names}, @code{standard names}, -and @code{classes}. -@item -@option{Option flags} +@itemize * -@item -@file{File names}, @samp{button names}, and @samp{field names}. +@item +@cite{Functions}, @cite{utility program names}, @cite{standard names}, +and @cite{classes}. -@item -@code{Variables}, @env{environment variables}, and @var{metasyntactic -variables}. +@item +@cite{Option flags} -@item -@emph{Emphasis}. +@item +@code{File names} -@item -@r{[}optional information or parameters@r{]} +@item +@cite{Variables} -@item +@item +@emph{Emphasis} + +@item +[optional information or parameters] + +@item Examples are described by text -@smallexample + +@example and then shown this way. -@end smallexample -@end itemize +@end example -@noindent -Commands that are entered by the user are preceded in this manual by the -characters @w{``@code{$ }''} (dollar sign followed by space). If your system -uses this sequence as a prompt, then the commands will appear exactly as -you see them in the manual. If your system uses some other prompt, then -the command will appear with the @code{$} replaced by whatever prompt -character you are using. +@item +Commands that are entered by the user are shown as preceded by a prompt string +comprising the @code{$} character followed by a space. -Full file names are shown with the ``@code{/}'' character -as the directory separator; e.g., @file{parent-dir/subdir/myfile.adb}. +@item +Full file names are shown with the '/' character +as the directory separator; e.g., @code{parent-dir/subdir/myfile.adb}. If you are using GNAT on a Windows platform, please note that -the ``@code{\}'' character should be used instead. +the '\' character should be used instead. +@end itemize -@c **************************** -@node Getting Started with GNAT +@node Getting Started with GNAT,The GNAT Compilation Model,About This Guide,Top +@anchor{gnat_ugn/getting_started_with_gnat getting-started-with-gnat}@anchor{8}@anchor{gnat_ugn/getting_started_with_gnat doc}@anchor{31}@anchor{gnat_ugn/getting_started_with_gnat id1}@anchor{32} @chapter Getting Started with GNAT -@noindent -This chapter describes some simple ways of using GNAT to build + +This chapter describes how to use GNAT's command line interface to build executable Ada programs. -@ref{Running GNAT}, through @ref{Using the gnatmake Utility}, -show how to use the command line environment. -@ref{Introduction to GPS}, provides a brief -introduction to the GNAT Programming Studio, a visually-oriented -Integrated Development Environment for GNAT. -GPS offers a graphical ``look and feel'', support for development in +On most platforms a visually oriented Integrated Development Environment +is also available, the GNAT Programming Studio (GPS). +GPS offers a graphical "look and feel", support for development in other programming languages, comprehensive browsing features, and many other capabilities. For information on GPS please refer to @cite{Using the GNAT Programming Studio}. @menu -* Running GNAT:: -* Running a Simple Ada Program:: -* Running a Program with Multiple Units:: -* Using the gnatmake Utility:: -* Introduction to GPS:: +* Running GNAT:: +* Running a Simple Ada Program:: +* Running a Program with Multiple Units:: +* Using the gnatmake Utility:: + @end menu -@node Running GNAT +@node Running GNAT,Running a Simple Ada Program,,Getting Started with GNAT +@anchor{gnat_ugn/getting_started_with_gnat running-gnat}@anchor{33}@anchor{gnat_ugn/getting_started_with_gnat id2}@anchor{34} @section Running GNAT -@noindent + Three steps are needed to create an executable file from an Ada source file: -@enumerate -@item + +@itemize * + +@item The source file(s) must be compiled. -@item + +@item The file(s) must be bound using the GNAT binder. -@item + +@item All appropriate object files must be linked to produce an executable. -@end enumerate +@end itemize -@noindent -All three steps are most commonly handled by using the @command{gnatmake} +All three steps are most commonly handled by using the @emph{gnatmake} utility program that, given the name of the main program, automatically performs the necessary compilation, binding and linking steps. -@node Running a Simple Ada Program +@node Running a Simple Ada Program,Running a Program with Multiple Units,Running GNAT,Getting Started with GNAT +@anchor{gnat_ugn/getting_started_with_gnat running-a-simple-ada-program}@anchor{35}@anchor{gnat_ugn/getting_started_with_gnat id3}@anchor{36} @section Running a Simple Ada Program -@noindent + Any text editor may be used to prepare an Ada program. -(If @code{Emacs} is -used, the optional Ada mode may be helpful in laying out the program.) -The -program text is a normal text file. We will assume in our initial +(If Emacs is used, the optional Ada mode may be helpful in laying out the +program.) +The program text is a normal text file. We will assume in our initial example that you have used your editor to prepare the following standard format text file: -@smallexample @c ada -@cartouche -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{procedure} Hello @b{is} -@b{begin} +@example +with Ada.Text_IO; use Ada.Text_IO; +procedure Hello is +begin Put_Line ("Hello WORLD!"); -@b{end} Hello; -@end cartouche -@end smallexample +end Hello; +@end example -@noindent -This file should be named @file{hello.adb}. +This file should be named @code{hello.adb}. With the normal default file naming conventions, GNAT requires that each file contain a single compilation unit whose file name is the unit name, with periods replaced by hyphens; the -extension is @file{ads} for a -spec and @file{adb} for a body. +extension is @code{ads} for a +spec and @code{adb} for a body. You can override this default file naming convention by use of the -special pragma @code{Source_File_Name} (@pxref{Using Other File Names}). +special pragma @cite{Source_File_Name} (for further information please +see @ref{37,,Using Other File Names}). Alternatively, if you want to rename your files according to this default convention, which is probably more convenient if you will be using GNAT -for all your compilations, then the @code{gnatchop} utility +for all your compilations, then the @cite{gnatchop} utility can be used to generate correctly-named source files -(@pxref{Renaming Files with gnatchop}). +(see @ref{38,,Renaming Files with gnatchop}). -You can compile the program using the following command (@code{$} is used +You can compile the program using the following command (@cite{$} is used as the command prompt in the examples in this document): -@smallexample +@example $ gcc -c hello.adb -@end smallexample +@end example -@noindent -@command{gcc} is the command used to run the compiler. This compiler is +@emph{gcc} is the command used to run the compiler. This compiler is capable of compiling programs in several languages, including Ada and C. It assumes that you have given it an Ada program if the file extension is -either @file{.ads} or @file{.adb}, and it will then call +either @code{.ads} or @code{.adb}, and it will then call the GNAT compiler to compile the specified file. -The @option{-c} switch is required. It tells @command{gcc} to only do a -compilation. (For C programs, @command{gcc} can also do linking, but this -capability is not used directly for Ada programs, so the @option{-c} +The @code{-c} switch is required. It tells @emph{gcc} to only do a +compilation. (For C programs, @emph{gcc} can also do linking, but this +capability is not used directly for Ada programs, so the @code{-c} switch must always be present.) This compile command generates a file -@file{hello.o}, which is the object +@code{hello.o}, which is the object file corresponding to your Ada program. It also generates -an ``Ada Library Information'' file @file{hello.ali}, +an 'Ada Library Information' file @code{hello.ali}, which contains additional information used to check that an Ada program is consistent. To build an executable file, -use @code{gnatbind} to bind the program -and @command{gnatlink} to link it. The -argument to both @code{gnatbind} and @command{gnatlink} is the name of the -@file{ALI} file, but the default extension of @file{.ali} can +use @cite{gnatbind} to bind the program +and @emph{gnatlink} to link it. The +argument to both @cite{gnatbind} and @emph{gnatlink} is the name of the +@code{ALI} file, but the default extension of @code{.ali} can be omitted. This means that in the most common case, the argument is simply the name of the main program: -@smallexample +@example $ gnatbind hello $ gnatlink hello -@end smallexample +@end example -@noindent -A simpler method of carrying out these steps is to use -@command{gnatmake}, +A simpler method of carrying out these steps is to use @emph{gnatmake}, a master program that invokes all the required compilation, binding and linking tools in the correct order. In particular, -@command{gnatmake} automatically recompiles any sources that have been +@emph{gnatmake} automatically recompiles any sources that have been modified since they were last compiled, or sources that depend -on such modified sources, so that ``version skew'' is avoided. -@cindex Version skew (avoided by @command{gnatmake}) +on such modified sources, so that 'version skew' is avoided. + +@geindex Version skew (avoided by *gnatmake*) -@smallexample +@example $ gnatmake hello.adb -@end smallexample +@end example -@noindent -The result is an executable program called @file{hello}, which can be +The result is an executable program called @code{hello}, which can be run by entering: -@smallexample +@example $ hello -@end smallexample +@end example -@noindent assuming that the current directory is on the search path for executable programs. -@noindent -and, if all has gone well, you will see +and, if all has gone well, you will see: -@smallexample +@example Hello WORLD! -@end smallexample +@end example -@noindent appear in response to this command. -@c **************************************** -@node Running a Program with Multiple Units +@node Running a Program with Multiple Units,Using the gnatmake Utility,Running a Simple Ada Program,Getting Started with GNAT +@anchor{gnat_ugn/getting_started_with_gnat id4}@anchor{39}@anchor{gnat_ugn/getting_started_with_gnat running-a-program-with-multiple-units}@anchor{3a} @section Running a Program with Multiple Units -@noindent + Consider a slightly more complicated example that has three files: a main program, and the spec and body of a package: -@smallexample @c ada -@cartouche -@group -@b{package} Greetings @b{is} - @b{procedure} Hello; - @b{procedure} Goodbye; -@b{end} Greetings; - -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{package} @b{body} Greetings @b{is} - @b{procedure} Hello @b{is} - @b{begin} +@example +package Greetings is + procedure Hello; + procedure Goodbye; +end Greetings; + +with Ada.Text_IO; use Ada.Text_IO; +package body Greetings is + procedure Hello is + begin Put_Line ("Hello WORLD!"); - @b{end} Hello; + end Hello; - @b{procedure} Goodbye @b{is} - @b{begin} + procedure Goodbye is + begin Put_Line ("Goodbye WORLD!"); - @b{end} Goodbye; -@b{end} Greetings; -@end group - -@group -@b{with} Greetings; -@b{procedure} Gmain @b{is} -@b{begin} + end Goodbye; +end Greetings; + +with Greetings; +procedure Gmain is +begin Greetings.Hello; Greetings.Goodbye; -@b{end} Gmain; -@end group -@end cartouche -@end smallexample +end Gmain; +@end example -@noindent Following the one-unit-per-file rule, place this program in the following three separate files: -@table @file -@item greetings.ads -spec of package @code{Greetings} -@item greetings.adb -body of package @code{Greetings} +@table @asis + +@item @emph{greetings.ads} + +spec of package @cite{Greetings} + +@item @emph{greetings.adb} + +body of package @cite{Greetings} + +@item @emph{gmain.adb} -@item gmain.adb body of main program @end table -@noindent To build an executable version of this program, we could use four separate steps to compile, bind, and link the program, as follows: -@smallexample +@example $ gcc -c gmain.adb $ gcc -c greetings.adb $ gnatbind gmain $ gnatlink gmain -@end smallexample +@end example -@noindent Note that there is no required order of compilation when using GNAT. In particular it is perfectly fine to compile the main program first. Also, it is not necessary to compile package specs in the case where there is an accompanying body; you only need to compile the body. If you want to submit these files to the compiler for semantic checking and not code -generation, then use the -@option{-gnatc} switch: +generation, then use the @code{-gnatc} switch: -@smallexample +@example $ gcc -c greetings.ads -gnatc -@end smallexample +@end example -@noindent Although the compilation can be done in separate steps as in the above example, in practice it is almost always more convenient -to use the @command{gnatmake} tool. All you need to know in this case +to use the @emph{gnatmake} tool. All you need to know in this case is the name of the main program's source file. The effect of the above four commands can be achieved with a single one: -@smallexample +@example $ gnatmake gmain.adb -@end smallexample +@end example -@noindent -In the next section we discuss the advantages of using @command{gnatmake} in +In the next section we discuss the advantages of using @emph{gnatmake} in more detail. -@c ***************************** -@node Using the gnatmake Utility -@section Using the @command{gnatmake} Utility +@node Using the gnatmake Utility,,Running a Program with Multiple Units,Getting Started with GNAT +@anchor{gnat_ugn/getting_started_with_gnat using-the-gnatmake-utility}@anchor{3b}@anchor{gnat_ugn/getting_started_with_gnat id5}@anchor{3c} +@section Using the @emph{gnatmake} Utility + -@noindent If you work on a program by compiling single components at a time using -@command{gcc}, you typically keep track of the units you modify. In order to +@emph{gcc}, you typically keep track of the units you modify. In order to build a consistent system, you compile not only these units, but also any units that depend on the units you have modified. For example, in the preceding case, -if you edit @file{gmain.adb}, you only need to recompile that file. But if -you edit @file{greetings.ads}, you must recompile both -@file{greetings.adb} and @file{gmain.adb}, because both files contain -units that depend on @file{greetings.ads}. +if you edit @code{gmain.adb}, you only need to recompile that file. But if +you edit @code{greetings.ads}, you must recompile both +@code{greetings.adb} and @code{gmain.adb}, because both files contain +units that depend on @code{greetings.ads}. -@code{gnatbind} will warn you if you forget one of these compilation +@emph{gnatbind} will warn you if you forget one of these compilation steps, so that it is impossible to generate an inconsistent program as a result of forgetting to do a compilation. Nevertheless it is tedious and error-prone to keep track of dependencies among units. @@ -835,608 +1257,474 @@ if the dependencies change as you change the program, you must make sure that the makefile is kept up-to-date manually, which is also an error-prone process. -The @command{gnatmake} utility takes care of these details automatically. +The @emph{gnatmake} utility takes care of these details automatically. Invoke it using either one of the following forms: -@smallexample +@example $ gnatmake gmain.adb $ gnatmake gmain -@end smallexample +@end example -@noindent The argument is the name of the file containing the main program; -you may omit the extension. @command{gnatmake} +you may omit the extension. @emph{gnatmake} examines the environment, automatically recompiles any files that need recompiling, and binds and links the resulting set of object files, -generating the executable file, @file{gmain}. +generating the executable file, @code{gmain}. In a large program, it -can be extremely helpful to use @command{gnatmake}, because working out by hand +can be extremely helpful to use @emph{gnatmake}, because working out by hand what needs to be recompiled can be difficult. -Note that @command{gnatmake} -takes into account all the Ada rules that +Note that @emph{gnatmake} takes into account all the Ada rules that establish dependencies among units. These include dependencies that result from inlining subprogram bodies, and from generic instantiation. Unlike some other -Ada make tools, @command{gnatmake} does not rely on the dependencies that were +Ada make tools, @emph{gnatmake} does not rely on the dependencies that were found by the compiler on a previous compilation, which may possibly -be wrong when sources change. @command{gnatmake} determines the exact set of +be wrong when sources change. @emph{gnatmake} determines the exact set of dependencies from scratch each time it is run. +@c -- Example: A |withing| unit has a |with| clause, it |withs| a |withed| unit + +@node The GNAT Compilation Model,Building Executable Programs with GNAT,Getting Started with GNAT,Top +@anchor{gnat_ugn/the_gnat_compilation_model doc}@anchor{3d}@anchor{gnat_ugn/the_gnat_compilation_model the-gnat-compilation-model}@anchor{9}@anchor{gnat_ugn/the_gnat_compilation_model id1}@anchor{3e} +@chapter The GNAT Compilation Model -@node Introduction to GPS -@section Introduction to GPS -@cindex GPS (GNAT Programming Studio) -@cindex GNAT Programming Studio (GPS) -@noindent -Although the command line interface (@command{gnatmake}, etc.) alone -is sufficient, a graphical Interactive Development -Environment can make it easier for you to compose, navigate, and debug -programs. This section describes the main features of GPS -(``GNAT Programming Studio''), the GNAT graphical IDE. -You will see how to use GPS to build and debug an executable, and -you will also learn some of the basics of the GNAT ``project'' facility. - -GPS enables you to do much more than is presented here; -e.g., you can produce a call graph, interface to a third-party -Version Control System, and inspect the generated assembly language -for a program. -Indeed, GPS also supports languages other than Ada. -Such additional information, and an explanation of all of the GPS menu -items. may be found in the on-line help, which includes -a user's guide and a tutorial (these are also accessible from the GNAT -startup menu). -@menu -* Building a New Program with GPS:: -* Simple Debugging with GPS:: -@end menu +@geindex GNAT compilation model -@node Building a New Program with GPS -@subsection Building a New Program with GPS -@noindent -GPS invokes the GNAT compilation tools using information -contained in a @emph{project} (also known as a @emph{project file}): -a collection of properties such -as source directories, identities of main subprograms, tool switches, etc., -and their associated values. -See @ref{GNAT Project Manager} for details. -In order to run GPS, you will need to either create a new project -or else open an existing one. - -This section will explain how you can use GPS to create a project, -to associate Ada source files with a project, and to build and run -programs. - -@enumerate -@item @emph{Creating a project} - -Invoke GPS, either from the command line or the platform's IDE. -After it starts, GPS will display a ``Welcome'' screen with three -radio buttons: - -@itemize @bullet -@item -@code{Start with default project in directory} +@geindex Compilation model -@item -@code{Create new project with wizard} +This chapter describes the compilation model used by GNAT. Although +similar to that used by other languages such as C and C++, this model +is substantially different from the traditional Ada compilation models, +which are based on a centralized program library. The chapter covers +the following material: -@item -@code{Open existing project} + +@itemize * + +@item +Topics related to source file makeup and naming + + +@itemize * + +@item +@ref{3f,,Source Representation} + +@item +@ref{40,,Foreign Language Representation} + +@item +@ref{41,,File Naming Topics and Utilities} @end itemize -@noindent -Select @code{Create new project with wizard} and press @code{OK}. -A new window will appear. In the text box labeled with -@code{Enter the name of the project to create}, type @file{sample} -as the project name. -In the next box, browse to choose the directory in which you -would like to create the project file. -After selecting an appropriate directory, press @code{Forward}. - -A window will appear with the title -@code{Version Control System Configuration}. -Simply press @code{Forward}. - -A window will appear with the title -@code{Please select the source directories for this project}. -The directory that you specified for the project file will be selected -by default as the one to use for sources; simply press @code{Forward}. - -A window will appear with the title -@code{Please select the build directory for this project}. -The directory that you specified for the project file will be selected -by default for object files and executables; -simply press @code{Forward}. - -A window will appear with the title -@code{Please select the main units for this project}. -You will supply this information later, after creating the source file. -Simply press @code{Forward} for now. - -A window will appear with the title -@code{Please select the switches to build the project}. -Press @code{Apply}. This will create a project file named -@file{sample.prj} in the directory that you had specified. - -@item @emph{Creating and saving the source file} - -After you create the new project, a GPS window will appear, which is -partitioned into two main sections: - -@itemize @bullet -@item -A @emph{Workspace area}, initially greyed out, which you will use for -creating and editing source files +@item +@ref{16,,Configuration Pragmas} -@item -Directly below, a @emph{Messages area}, which initially displays a -``Welcome'' message. -(If the Messages area is not visible, drag its border upward to expand it.) +@item +@ref{42,,Generating Object Files} + +@item +@ref{43,,Source Dependencies} + +@item +@ref{44,,The Ada Library Information Files} + +@item +@ref{45,,Binding an Ada Program} + +@item +@ref{17,,GNAT and Libraries} + +@item +@ref{18,,Conditional Compilation} + +@item +@ref{46,,Mixed Language Programming} + +@item +@ref{47,,GNAT and Other Compilation Models} + +@item +@ref{1c,,Using GNAT Files with External Tools} @end itemize -@noindent -Select @code{File} on the menu bar, and then the @code{New} command. -The Workspace area will become white, and you can now -enter the source program explicitly. -Type the following text - -@smallexample @c ada -@group -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{procedure} Hello @b{is} -@b{begin} - Put_Line("Hello from GPS!"); -@b{end} Hello; -@end group -@end smallexample - -@noindent -Select @code{File}, then @code{Save As}, and enter the source file name -@file{hello.adb}. -The file will be saved in the same directory you specified as the -location of the default project file. - -@item @emph{Updating the project file} - -You need to add the new source file to the project. -To do this, select -the @code{Project} menu and then @code{Edit project properties}. -Click the @code{Main files} tab on the left, and then the -@code{Add} button. -Choose @file{hello.adb} from the list, and press @code{Open}. -The project settings window will reflect this action. -Click @code{OK}. - -@item @emph{Building and running the program} - -In the main GPS window, now choose the @code{Build} menu, then @code{Make}, -and select @file{hello.adb}. -The Messages window will display the resulting invocations of @command{gcc}, -@command{gnatbind}, and @command{gnatlink} -(reflecting the default switch settings from the -project file that you created) and then a ``successful compilation/build'' -message. - -To run the program, choose the @code{Build} menu, then @code{Run}, and -select @command{hello}. -An @emph{Arguments Selection} window will appear. -There are no command line arguments, so just click @code{OK}. - -The Messages window will now display the program's output (the string -@code{Hello from GPS}), and at the bottom of the GPS window a status -update is displayed (@code{Run: hello}). -Close the GPS window (or select @code{File}, then @code{Exit}) to -terminate this GPS session. -@end enumerate +@menu +* Source Representation:: +* Foreign Language Representation:: +* File Naming Topics and Utilities:: +* Configuration Pragmas:: +* Generating Object Files:: +* Source Dependencies:: +* The Ada Library Information Files:: +* Binding an Ada Program:: +* GNAT and Libraries:: +* Conditional Compilation:: +* Mixed Language Programming:: +* GNAT and Other Compilation Models:: +* Using GNAT Files with External Tools:: -@node Simple Debugging with GPS -@subsection Simple Debugging with GPS -@noindent -This section illustrates basic debugging techniques (setting breakpoints, -examining/modifying variables, single stepping). - -@enumerate -@item @emph{Opening a project} - -Start GPS and select @code{Open existing project}; browse to -specify the project file @file{sample.prj} that you had created in the -earlier example. - -@item @emph{Creating a source file} - -Select @code{File}, then @code{New}, and type in the following program: - -@smallexample @c ada -@group -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{procedure} Example @b{is} - Line : String (1..80); - N : Natural; -@b{begin} - Put_Line("Type a line of text at each prompt; an empty line to exit"); - @b{loop} - Put(": "); - Get_Line (Line, N); - Put_Line (Line (1..N) ); - @b{exit} @b{when} N=0; - @b{end} @b{loop}; -@b{end} Example; -@end group -@end smallexample - -@noindent -Select @code{File}, then @code{Save as}, and enter the file name -@file{example.adb}. - -@item @emph{Updating the project file} - -Add @code{Example} as a new main unit for the project: -@enumerate a -@item -Select @code{Project}, then @code{Edit Project Properties}. +@end menu + +@node Source Representation,Foreign Language Representation,,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model source-representation}@anchor{3f}@anchor{gnat_ugn/the_gnat_compilation_model id2}@anchor{48} +@section Source Representation + + +@geindex Latin-1 + +@geindex VT +@geindex HT +@geindex CR +@geindex LF +@geindex FF + +Ada source programs are represented in standard text files, using +Latin-1 coding. Latin-1 is an 8-bit code that includes the familiar +7-bit ASCII set, plus additional characters used for +representing foreign languages (see @ref{40,,Foreign Language Representation} +for support of non-USA character sets). The format effector characters +are represented using their standard ASCII encodings, as follows: +@quotation + + +@multitable {xxxxxxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxx} {xxxxxxxxxxx} @item -Select the @code{Main files} tab, click @code{Add}, then -select the file @file{example.adb} from the list, and -click @code{Open}. -You will see the file name appear in the list of main units + +Character + +@tab + +Effect + +@tab + +Code @item -Click @code{OK} -@end enumerate -@item @emph{Building/running the executable} +@code{VT} -To build the executable -select @code{Build}, then @code{Make}, and then choose @file{example.adb}. +@tab -Run the program to see its effect (in the Messages area). -Each line that you enter is displayed; an empty line will -cause the loop to exit and the program to terminate. +Vertical tab -@item @emph{Debugging the program} +@tab -Note that the @option{-g} switches to @command{gcc} and @command{gnatlink}, -which are required for debugging, are on by default when you create -a new project. -Thus unless you intentionally remove these settings, you will be able -to debug any program that you develop using GPS. +@cite{16#0B#} -@enumerate a -@item @emph{Initializing} +@item -Select @code{Debug}, then @code{Initialize}, then @file{example} +@code{HT} -@item @emph{Setting a breakpoint} +@tab -After performing the initialization step, you will observe a small -icon to the right of each line number. -This serves as a toggle for breakpoints; clicking the icon will -set a breakpoint at the corresponding line (the icon will change to -a red circle with an ``x''), and clicking it again -will remove the breakpoint / reset the icon. +Horizontal tab -For purposes of this example, set a breakpoint at line 10 (the -statement @code{Put_Line@ (Line@ (1..N));} +@tab -@item @emph{Starting program execution} +@cite{16#09#} -Select @code{Debug}, then @code{Run}. When the -@code{Program Arguments} window appears, click @code{OK}. -A console window will appear; enter some line of text, -e.g.@: @code{abcde}, at the prompt. -The program will pause execution when it gets to the -breakpoint, and the corresponding line is highlighted. +@item -@item @emph{Examining a variable} +@code{CR} -Move the mouse over one of the occurrences of the variable @code{N}. -You will see the value (5) displayed, in ``tool tip'' fashion. -Right click on @code{N}, select @code{Debug}, then select @code{Display N}. -You will see information about @code{N} appear in the @code{Debugger Data} -pane, showing the value as 5. +@tab -@item @emph{Assigning a new value to a variable} +Carriage return -Right click on the @code{N} in the @code{Debugger Data} pane, and -select @code{Set value of N}. -When the input window appears, enter the value @code{4} and click -@code{OK}. -This value does not automatically appear in the @code{Debugger Data} -pane; to see it, right click again on the @code{N} in the -@code{Debugger Data} pane and select @code{Update value}. -The new value, 4, will appear in red. +@tab -@item @emph{Single stepping} +@cite{16#0D#} -Select @code{Debug}, then @code{Next}. -This will cause the next statement to be executed, in this case the -call of @code{Put_Line} with the string slice. -Notice in the console window that the displayed string is simply -@code{abcd} and not @code{abcde} which you had entered. -This is because the upper bound of the slice is now 4 rather than 5. +@item -@item @emph{Removing a breakpoint} +@code{LF} -Toggle the breakpoint icon at line 10. +@tab -@item @emph{Resuming execution from a breakpoint} +Line feed -Select @code{Debug}, then @code{Continue}. -The program will reach the next iteration of the loop, and -wait for input after displaying the prompt. -This time, just hit the @kbd{Enter} key. -The value of @code{N} will be 0, and the program will terminate. -The console window will disappear. -@end enumerate -@end enumerate +@tab -@node The GNAT Compilation Model -@chapter The GNAT Compilation Model -@cindex GNAT compilation model -@cindex Compilation model +@cite{16#0A#} -@menu -* Source Representation:: -* Foreign Language Representation:: -* File Naming Rules:: -* Using Other File Names:: -* Alternative File Naming Schemes:: -* Generating Object Files:: -* Source Dependencies:: -* The Ada Library Information Files:: -* Binding an Ada Program:: -* Mixed Language Programming:: -* Building Mixed Ada & C++ Programs:: -* Comparison between GNAT and C/C++ Compilation Models:: -* Comparison between GNAT and Conventional Ada Library Models:: -@end menu +@item -@noindent -This chapter describes the compilation model used by GNAT. Although -similar to that used by other languages, such as C and C++, this model -is substantially different from the traditional Ada compilation models, -which are based on a library. The model is initially described without -reference to the library-based model. If you have not previously used an -Ada compiler, you need only read the first part of this chapter. The -last section describes and discusses the differences between the GNAT -model and the traditional Ada compiler models. If you have used other -Ada compilers, this section will help you to understand those -differences, and the advantages of the GNAT model. - -@node Source Representation -@section Source Representation -@cindex Latin-1 +@code{FF} -@noindent -Ada source programs are represented in standard text files, using -Latin-1 coding. Latin-1 is an 8-bit code that includes the familiar -7-bit ASCII set, plus additional characters used for -representing foreign languages (@pxref{Foreign Language Representation} -for support of non-USA character sets). The format effector characters -are represented using their standard ASCII encodings, as follows: +@tab -@table @code -@item VT -@findex VT -Vertical tab, @code{16#0B#} +Form feed -@item HT -@findex HT -Horizontal tab, @code{16#09#} +@tab -@item CR -@findex CR -Carriage return, @code{16#0D#} +@cite{16#0C#} -@item LF -@findex LF -Line feed, @code{16#0A#} +@end multitable -@item FF -@findex FF -Form feed, @code{16#0C#} -@end table +@end quotation -@noindent Source files are in standard text file format. In addition, GNAT will recognize a wide variety of stream formats, in which the end of physical lines is marked by any of the following sequences: -@code{LF}, @code{CR}, @code{CR-LF}, or @code{LF-CR}. This is useful +@cite{LF}, @cite{CR}, @cite{CR-LF}, or @cite{LF-CR}. This is useful in accommodating files that are imported from other operating systems. -@cindex End of source file -@cindex Source file, end -@findex SUB +@geindex End of source file; Source file@comma{} end + +@geindex SUB (control character) + The end of a source file is normally represented by the physical end of -file. However, the control character @code{16#1A#} (@code{SUB}) is also +file. However, the control character @cite{16#1A#} (@code{SUB}) is also recognized as signalling the end of the source file. Again, this is provided for compatibility with other operating systems where this code is used to represent the end of file. +@geindex spec (definition) +@geindex compilation (definition) + Each file contains a single Ada compilation unit, including any pragmas associated with the unit. For example, this means you must place a -package declaration (a package @dfn{spec}) and the corresponding body in -separate files. An Ada @dfn{compilation} (which is a sequence of +package declaration (a package @cite{spec}) and the corresponding body in +separate files. An Ada @cite{compilation} (which is a sequence of compilation units) is represented using a sequence of files. Similarly, you will place each subunit or child unit in a separate file. -@node Foreign Language Representation +@node Foreign Language Representation,File Naming Topics and Utilities,Source Representation,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model foreign-language-representation}@anchor{40}@anchor{gnat_ugn/the_gnat_compilation_model id3}@anchor{49} @section Foreign Language Representation -@noindent + GNAT supports the standard character sets defined in Ada as well as several other non-standard character sets for use in localized versions -of the compiler (@pxref{Character Set Control}). +of the compiler (@ref{4a,,Character Set Control}). + @menu -* Latin-1:: -* Other 8-Bit Codes:: -* Wide_Character Encodings:: -* Wide_Wide_Character Encodings:: +* Latin-1:: +* Other 8-Bit Codes:: +* Wide_Character Encodings:: +* Wide_Wide_Character Encodings:: + @end menu -@node Latin-1 +@node Latin-1,Other 8-Bit Codes,,Foreign Language Representation +@anchor{gnat_ugn/the_gnat_compilation_model id4}@anchor{4b}@anchor{gnat_ugn/the_gnat_compilation_model latin-1}@anchor{4c} @subsection Latin-1 -@cindex Latin-1 -@noindent + +@geindex Latin-1 + The basic character set is Latin-1. This character set is defined by ISO -standard 8859, part 1. The lower half (character codes @code{16#00#} -@dots{} @code{16#7F#)} is identical to standard ASCII coding, but the upper +standard 8859, part 1. The lower half (character codes @cite{16#00#} +... @cite{16#7F#)} is identical to standard ASCII coding, but the upper half is used to represent additional characters. These include extended letters used by European languages, such as French accents, the vowels with umlauts used in German, and the extra letter A-ring used in Swedish. -@findex Ada.Characters.Latin_1 +@geindex Ada.Characters.Latin_1 + For a complete list of Latin-1 codes and their encodings, see the source -file of library unit @code{Ada.Characters.Latin_1} in file -@file{a-chlat1.ads}. +file of library unit @cite{Ada.Characters.Latin_1} in file +@code{a-chlat1.ads}. You may use any of these extended characters freely in character or string literals. In addition, the extended characters that represent letters can be used in identifiers. -@node Other 8-Bit Codes +@node Other 8-Bit Codes,Wide_Character Encodings,Latin-1,Foreign Language Representation +@anchor{gnat_ugn/the_gnat_compilation_model other-8-bit-codes}@anchor{4d}@anchor{gnat_ugn/the_gnat_compilation_model id5}@anchor{4e} @subsection Other 8-Bit Codes -@noindent + GNAT also supports several other 8-bit coding schemes: +@geindex Latin-2 + +@geindex ISO 8859-2 + + @table @asis -@item ISO 8859-2 (Latin-2) -@cindex Latin-2 -@cindex ISO 8859-2 + +@item @emph{ISO 8859-2 (Latin-2)} + Latin-2 letters allowed in identifiers, with uppercase and lowercase equivalence. +@end table + +@geindex Latin-3 + +@geindex ISO 8859-3 + + +@table @asis + +@item @emph{ISO 8859-3 (Latin-3)} -@item ISO 8859-3 (Latin-3) -@cindex Latin-3 -@cindex ISO 8859-3 Latin-3 letters allowed in identifiers, with uppercase and lowercase equivalence. +@end table + +@geindex Latin-4 + +@geindex ISO 8859-4 + + +@table @asis + +@item @emph{ISO 8859-4 (Latin-4)} -@item ISO 8859-4 (Latin-4) -@cindex Latin-4 -@cindex ISO 8859-4 Latin-4 letters allowed in identifiers, with uppercase and lowercase equivalence. +@end table + +@geindex ISO 8859-5 + +@geindex Cyrillic + + +@table @asis + +@item @emph{ISO 8859-5 (Cyrillic)} -@item ISO 8859-5 (Cyrillic) -@cindex ISO 8859-5 -@cindex Cyrillic ISO 8859-5 letters (Cyrillic) allowed in identifiers, with uppercase and lowercase equivalence. +@end table + +@geindex ISO 8859-15 + +@geindex Latin-9 + + +@table @asis + +@item @emph{ISO 8859-15 (Latin-9)} -@item ISO 8859-15 (Latin-9) -@cindex ISO 8859-15 -@cindex Latin-9 ISO 8859-15 (Latin-9) letters allowed in identifiers, with uppercase and lowercase equivalence +@end table + +@geindex code page 437 (IBM PC) + + +@table @asis + +@item @emph{IBM PC (code page 437)} -@item IBM PC (code page 437) -@cindex code page 437 This code page is the normal default for PCs in the U.S. It corresponds to the original IBM PC character set. This set has some, but not all, of the extended Latin-1 letters, but these letters do not have the same encoding as Latin-1. In this mode, these letters are allowed in identifiers with uppercase and lowercase equivalence. +@end table + +@geindex code page 850 (IBM PC) + + +@table @asis + +@item @emph{IBM PC (code page 850)} -@item IBM PC (code page 850) -@cindex code page 850 This code page is a modification of 437 extended to include all the Latin-1 letters, but still not with the usual Latin-1 encoding. In this mode, all these letters are allowed in identifiers with uppercase and lowercase equivalence. -@item Full Upper 8-bit +@item @emph{Full Upper 8-bit} + Any character in the range 80-FF allowed in identifiers, and all are considered distinct. In other words, there are no uppercase and lowercase equivalences in this range. This is useful in conjunction with certain encoding schemes used for some foreign character sets (e.g., the typical method of representing Chinese characters on the PC). -@item No Upper-Half +@item @emph{No Upper-Half} + No upper-half characters in the range 80-FF are allowed in identifiers. This gives Ada 83 compatibility for identifier names. @end table -@noindent For precise data on the encodings permitted, and the uppercase and lowercase -equivalences that are recognized, see the file @file{csets.adb} in +equivalences that are recognized, see the file @code{csets.adb} in the GNAT compiler sources. You will need to obtain a full source release of GNAT to obtain this file. -@node Wide_Character Encodings +@node Wide_Character Encodings,Wide_Wide_Character Encodings,Other 8-Bit Codes,Foreign Language Representation +@anchor{gnat_ugn/the_gnat_compilation_model id6}@anchor{4f}@anchor{gnat_ugn/the_gnat_compilation_model wide-character-encodings}@anchor{50} @subsection Wide_Character Encodings -@noindent + GNAT allows wide character codes to appear in character and string literals, and also optionally in identifiers, by means of the following possible encoding schemes: + @table @asis -@item Hex Coding +@item @emph{Hex Coding} + In this encoding, a wide character is represented by the following five character sequence: -@smallexample +@example ESC a b c d -@end smallexample +@end example -@noindent -Where @code{a}, @code{b}, @code{c}, @code{d} are the four hexadecimal +where @cite{a}, @cite{b}, @cite{c}, @cite{d} are the four hexadecimal characters (using uppercase letters) of the wide character code. For example, ESC A345 is used to represent the wide character with code -@code{16#A345#}. +@cite{16#A345#}. This scheme is compatible with use of the full Wide_Character set. -@item Upper-Half Coding -@cindex Upper-Half Coding -The wide character with encoding @code{16#abcd#} where the upper bit is on -(in other words, ``a'' is in the range 8-F) is represented as two bytes, -@code{16#ab#} and @code{16#cd#}. The second byte cannot be a format control +@item @emph{Upper-Half Coding} + +@geindex Upper-Half Coding + +The wide character with encoding @cite{16#abcd#} where the upper bit is on +(in other words, 'a' is in the range 8-F) is represented as two bytes, +@cite{16#ab#} and @cite{16#cd#}. The second byte cannot be a format control character, but is not required to be in the upper half. This method can be also used for shift-JIS or EUC, where the internal coding matches the external coding. -@item Shift JIS Coding -@cindex Shift JIS Coding +@item @emph{Shift JIS Coding} + +@geindex Shift JIS Coding + A wide character is represented by a two-character sequence, -@code{16#ab#} and -@code{16#cd#}, with the restrictions described for upper-half encoding as +@cite{16#ab#} and +@cite{16#cd#}, with the restrictions described for upper-half encoding as described above. The internal character code is the corresponding JIS character according to the standard algorithm for Shift-JIS conversion. Only characters defined in the JIS code set table can be used with this encoding method. -@item EUC Coding -@cindex EUC Coding +@item @emph{EUC Coding} + +@geindex EUC Coding + A wide character is represented by a two-character sequence -@code{16#ab#} and -@code{16#cd#}, with both characters being in the upper half. The internal +@cite{16#ab#} and +@cite{16#cd#}, with both characters being in the upper half. The internal character code is the corresponding JIS character according to the EUC encoding algorithm. Only characters defined in the JIS code set table can be used with this encoding method. -@item UTF-8 Coding +@item @emph{UTF-8 Coding} + A wide character is represented using UCS Transformation Format 8 (UTF-8) as defined in Annex R of ISO 10646-1/Am.2. Depending on the character value, the representation is a one, two, or three byte sequence: -@smallexample -@iftex -@leftskip=.7cm -@end iftex -16#0000#-16#007f#: 2#0@var{xxxxxxx}# -16#0080#-16#07ff#: 2#110@var{xxxxx}# 2#10@var{xxxxxx}# -16#0800#-16#ffff#: 2#1110@var{xxxx}# 2#10@var{xxxxxx}# 2#10@var{xxxxxx}# - -@end smallexample - -@noindent -where the @var{xxx} bits correspond to the left-padded bits of the + +@example +16#0000#-16#007f#: 2#0`xxxxxxx`# +16#0080#-16#07ff#: 2#110`xxxxx`# 2#10`xxxxxx`# +16#0800#-16#ffff#: 2#1110`xxxx`# 2#10`xxxxxx`# 2#10`xxxxxx`# +@end example + +where the @cite{xxx} bits correspond to the left-padded bits of the 16-bit character value. Note that all lower half ASCII characters are represented as ASCII bytes and all upper half characters and other wide characters are represented as sequences of upper-half @@ -1444,91 +1732,111 @@ other wide characters are represented as sequences of upper-half 6-byte sequences, and in the following section on wide wide characters, the use of these sequences is documented). -@item Brackets Coding +@item @emph{Brackets Coding} + In this encoding, a wide character is represented by the following eight character sequence: -@smallexample +@example [ " a b c d " ] -@end smallexample +@end example -@noindent -Where @code{a}, @code{b}, @code{c}, @code{d} are the four hexadecimal +where @cite{a}, @cite{b}, @cite{c}, @cite{d} are the four hexadecimal characters (using uppercase letters) of the wide character code. For -example, [``A345''] is used to represent the wide character with code -@code{16#A345#}. It is also possible (though not required) to use the +example, ['A345'] is used to represent the wide character with code +@cite{16#A345#}. It is also possible (though not required) to use the Brackets coding for upper half characters. For example, the code -@code{16#A3#} can be represented as @code{[``A3'']}. +@cite{16#A3#} can be represented as @cite{['A3']}. This scheme is compatible with use of the full Wide_Character set, and is also the method used for wide character encoding in some standard ACATS (Ada Conformity Assessment Test Suite) test suite distributions. - @end table -@noindent -Note: Some of these coding schemes do not permit the full use of the -Ada character set. For example, neither Shift JIS, nor EUC allow the +@cartouche +@quotation Note +Some of these coding schemes do not permit the full use of the +Ada character set. For example, neither Shift JIS nor EUC allow the use of the upper half of the Latin-1 set. +@end quotation +@end cartouche -@node Wide_Wide_Character Encodings +@node Wide_Wide_Character Encodings,,Wide_Character Encodings,Foreign Language Representation +@anchor{gnat_ugn/the_gnat_compilation_model id7}@anchor{51}@anchor{gnat_ugn/the_gnat_compilation_model wide-wide-character-encodings}@anchor{52} @subsection Wide_Wide_Character Encodings -@noindent + GNAT allows wide wide character codes to appear in character and string literals, and also optionally in identifiers, by means of the following possible encoding schemes: + @table @asis -@item UTF-8 Coding +@item @emph{UTF-8 Coding} + A wide character is represented using UCS Transformation Format 8 (UTF-8) as defined in Annex R of ISO 10646-1/Am.2. Depending on the character value, the representation of character codes with values greater than 16#FFFF# is a is a four, five, or six byte sequence: -@smallexample -@iftex -@leftskip=.7cm -@end iftex +@example 16#01_0000#-16#10_FFFF#: 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx 16#0020_0000#-16#03FF_FFFF#: 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 16#0400_0000#-16#7FFF_FFFF#: 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx -@end smallexample +@end example -@noindent -where the @var{xxx} bits correspond to the left-padded bits of the +where the @cite{xxx} bits correspond to the left-padded bits of the 32-bit character value. -@item Brackets Coding +@item @emph{Brackets Coding} + In this encoding, a wide wide character is represented by the following ten or twelve byte character sequence: -@smallexample +@example [ " a b c d e f " ] [ " a b c d e f g h " ] -@end smallexample +@end example -@noindent -Where @code{a-h} are the six or eight hexadecimal +where @cite{a-h} are the six or eight hexadecimal characters (using uppercase letters) of the wide wide character code. For example, ["1F4567"] is used to represent the wide wide character with code -@code{16#001F_4567#}. +@cite{16#001F_4567#}. This scheme is compatible with use of the full Wide_Wide_Character set, and is also the method used for wide wide character encoding in some standard ACATS (Ada Conformity Assessment Test Suite) test suite distributions. - @end table -@node File Naming Rules -@section File Naming Rules +@node File Naming Topics and Utilities,Configuration Pragmas,Foreign Language Representation,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model id8}@anchor{53}@anchor{gnat_ugn/the_gnat_compilation_model file-naming-topics-and-utilities}@anchor{41} +@section File Naming Topics and Utilities + + +GNAT has a default file naming scheme and also provides the user with +a high degree of control over how the names and extensions of the +source files correspond to the Ada compilation units that they contain. + +@menu +* File Naming Rules:: +* Using Other File Names:: +* Alternative File Naming Schemes:: +* Handling Arbitrary File Naming Conventions with gnatname:: +* File Name Krunching with gnatkr:: +* Renaming Files with gnatchop:: + +@end menu + +@node File Naming Rules,Using Other File Names,,File Naming Topics and Utilities +@anchor{gnat_ugn/the_gnat_compilation_model file-naming-rules}@anchor{54}@anchor{gnat_ugn/the_gnat_compilation_model id9}@anchor{55} +@subsection File Naming Rules + -@noindent The default file name is determined by the name of the unit that the file contains. The name is formed by taking the full expanded name of the unit and replacing the separating dots with hyphens and using @@ -1536,46 +1844,105 @@ lowercase for all letters. An exception arises if the file name generated by the above rules starts with one of the characters -@samp{a}, @samp{g}, @samp{i}, or @samp{s}, -and the second character is a +@cite{a}, @cite{g}, @cite{i}, or @cite{s}, and the second character is a minus. In this case, the character tilde is used in place of the minus. The reason for this special rule is to avoid clashes with the standard names for child units of the packages System, Ada, Interfaces, and GNAT, which use the prefixes -@samp{s-}, @samp{a-}, @samp{i-}, and @samp{g-}, +@cite{s-}, @cite{a-}, @cite{i-}, and @cite{g-}, respectively. -The file extension is @file{.ads} for a spec and -@file{.adb} for a body. The following list shows some +The file extension is @code{.ads} for a spec and +@code{.adb} for a body. The following table shows some examples of these rules. -@table @file -@item main.ads +@quotation + + +@multitable {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item + +Source File + +@tab + +Ada Compilation Unit + +@item + +@code{main.ads} + +@tab + Main (spec) -@item main.adb + +@item + +@code{main.adb} + +@tab + Main (body) -@item arith_functions.ads + +@item + +@code{arith_functions.ads} + +@tab + Arith_Functions (package spec) -@item arith_functions.adb + +@item + +@code{arith_functions.adb} + +@tab + Arith_Functions (package body) -@item func-spec.ads + +@item + +@code{func-spec.ads} + +@tab + Func.Spec (child package spec) -@item func-spec.adb + +@item + +@code{func-spec.adb} + +@tab + Func.Spec (child package body) -@item main-sub.adb + +@item + +@code{main-sub.adb} + +@tab + Sub (subunit of Main) -@item a~bad.adb + +@item + +@code{a~bad.adb} + +@tab + A.Bad (child package body) -@end table -@noindent +@end multitable + +@end quotation + Following these rules can result in excessively long file names if corresponding unit names are long (for example, if child units or subunits are heavily nested). An option is available to shorten such long file names -(called file name ``krunching''). This may be particularly useful when +(called file name 'krunching'). This may be particularly useful when programs being developed with GNAT are to be used on operating systems -with limited file name lengths. @xref{Using gnatkr}. +with limited file name lengths. @ref{56,,Using gnatkr}. Of course, no file shortening algorithm can guarantee uniqueness over all possible unit names; if file name krunching is used, it is your @@ -1584,44 +1951,43 @@ can specify the exact file names that you want used, as described in the next section. Finally, if your Ada programs are migrating from a compiler with a different naming convention, you can use the gnatchop utility to produce source files that follow the GNAT naming conventions. -(For details @pxref{Renaming Files with gnatchop}.) +(For details see @ref{38,,Renaming Files with gnatchop}.) + +Note: in the case of Windows or Mac OS operating systems, case is not +significant. So for example on @cite{Windows} if the canonical name is +@cite{main-sub.adb}, you can use the file name @code{Main-Sub.adb} instead. +However, case is significant for other operating systems, so for example, +if you want to use other than canonically cased file names on a Unix system, +you need to follow the procedures described in the next section. -Note: in the case of @code{Windows NT/XP} or @code{OpenVMS} operating -systems, case is not significant. So for example on @code{Windows XP} -if the canonical name is @code{main-sub.adb}, you can use the file name -@code{Main-Sub.adb} instead. However, case is significant for other -operating systems, so for example, if you want to use other than -canonically cased file names on a Unix system, you need to follow -the procedures described in the next section. +@node Using Other File Names,Alternative File Naming Schemes,File Naming Rules,File Naming Topics and Utilities +@anchor{gnat_ugn/the_gnat_compilation_model id10}@anchor{57}@anchor{gnat_ugn/the_gnat_compilation_model using-other-file-names}@anchor{37} +@subsection Using Other File Names -@node Using Other File Names -@section Using Other File Names -@cindex File names -@noindent +@geindex File names + In the previous section, we have described the default rules used by GNAT to determine the file name in which a given unit resides. It is often convenient to follow these default rules, and if you follow them, the compiler knows without being explicitly told where to find all the files it needs. +@geindex Source_File_Name pragma + However, in some cases, particularly when a program is imported from another Ada compiler environment, it may be more convenient for the programmer to specify which file names contain which units. GNAT allows arbitrary file names to be used by means of the Source_File_Name pragma. The form of this pragma is as shown in the following examples: -@cindex Source_File_Name pragma -@smallexample @c ada -@cartouche -@b{pragma} Source_File_Name (My_Utilities.Stacks, +@example +pragma Source_File_Name (My_Utilities.Stacks, Spec_File_Name => "myutilst_a.ada"); -@b{pragma} Source_File_name (My_Utilities.Stacks, +pragma Source_File_name (My_Utilities.Stacks, Body_File_Name => "myutilst.ada"); -@end cartouche -@end smallexample +@end example -@noindent As shown in this example, the first argument for the pragma is the unit name (in this example a child unit). The second argument has the form of a named association. The identifier @@ -1629,95 +1995,100 @@ indicates whether the file name is for a spec or a body; the file name itself is given by a string literal. The source file name pragma is a configuration pragma, which means that -normally it will be placed in the @file{gnat.adc} +normally it will be placed in the @code{gnat.adc} file used to hold configuration pragmas that apply to a complete compilation environment. -For more details on how the @file{gnat.adc} file is created and used -see @ref{Handling of Configuration Pragmas}. -@cindex @file{gnat.adc} +For more details on how the @code{gnat.adc} file is created and used +see @ref{58,,Handling of Configuration Pragmas}. + +@geindex gnat.adc GNAT allows completely arbitrary file names to be specified using the source file name pragma. However, if the file name specified has an -extension other than @file{.ads} or @file{.adb} it is necessary to use +extension other than @code{.ads} or @code{.adb} it is necessary to use a special syntax when compiling the file. The name in this case must be -preceded by the special sequence @option{-x} followed by a space and the name -of the language, here @code{ada}, as in: +preceded by the special sequence @emph{-x} followed by a space and the name +of the language, here @cite{ada}, as in: -@smallexample +@example $ gcc -c -x ada peculiar_file_name.sim -@end smallexample +@end example -@noindent -@command{gnatmake} handles non-standard file names in the usual manner (the +@cite{gnatmake} handles non-standard file names in the usual manner (the non-standard file name for the main program is simply used as the argument to gnatmake). Note that if the extension is also non-standard, -then it must be included in the @command{gnatmake} command, it may not +then it must be included in the @cite{gnatmake} command, it may not be omitted. -@node Alternative File Naming Schemes -@section Alternative File Naming Schemes -@cindex File naming schemes, alternative -@cindex File names +@node Alternative File Naming Schemes,Handling Arbitrary File Naming Conventions with gnatname,Using Other File Names,File Naming Topics and Utilities +@anchor{gnat_ugn/the_gnat_compilation_model id11}@anchor{59}@anchor{gnat_ugn/the_gnat_compilation_model alternative-file-naming-schemes}@anchor{5a} +@subsection Alternative File Naming Schemes + + +@geindex File naming schemes +@geindex alternative + +@geindex File names -In the previous section, we described the use of the @code{Source_File_Name} +The previous section described the use of the @cite{Source_File_Name} pragma to allow arbitrary names to be assigned to individual source files. However, this approach requires one pragma for each file, and especially in -large systems can result in very long @file{gnat.adc} files, and also create +large systems can result in very long @code{gnat.adc} files, and also create a maintenance problem. +@geindex Source_File_Name pragma + GNAT also provides a facility for specifying systematic file naming schemes other than the standard default naming scheme previously described. An alternative scheme for naming is specified by the use of -@code{Source_File_Name} pragmas having the following format: -@cindex Source_File_Name pragma +@cite{Source_File_Name} pragmas having the following format: -@smallexample @c ada -@b{pragma} Source_File_Name ( +@example +pragma Source_File_Name ( Spec_File_Name => FILE_NAME_PATTERN - @r{[},Casing => CASING_SPEC@r{]} - @r{[},Dot_Replacement => STRING_LITERAL@r{]}); + [ , Casing => CASING_SPEC] + [ , Dot_Replacement => STRING_LITERAL ] ); -@b{pragma} Source_File_Name ( +pragma Source_File_Name ( Body_File_Name => FILE_NAME_PATTERN - @r{[},Casing => CASING_SPEC@r{]} - @r{[},Dot_Replacement => STRING_LITERAL@r{]}); + [ , Casing => CASING_SPEC ] + [ , Dot_Replacement => STRING_LITERAL ] ) ; -@b{pragma} Source_File_Name ( +pragma Source_File_Name ( Subunit_File_Name => FILE_NAME_PATTERN - @r{[},Casing => CASING_SPEC@r{]} - @r{[},Dot_Replacement => STRING_LITERAL@r{]}); + [ , Casing => CASING_SPEC ] + [ , Dot_Replacement => STRING_LITERAL ] ) ; FILE_NAME_PATTERN ::= STRING_LITERAL CASING_SPEC ::= Lowercase | Uppercase | Mixedcase -@end smallexample +@end example -@noindent -The @code{FILE_NAME_PATTERN} string shows how the file name is constructed. +The @cite{FILE_NAME_PATTERN} string shows how the file name is constructed. It contains a single asterisk character, and the unit name is substituted systematically for this asterisk. The optional parameter -@code{Casing} indicates +@cite{Casing} indicates whether the unit name is to be all upper-case letters, all lower-case letters, or mixed-case. If no -@code{Casing} parameter is used, then the default is all +@cite{Casing} parameter is used, then the default is all lower-case. -The optional @code{Dot_Replacement} string is used to replace any periods -that occur in subunit or child unit names. If no @code{Dot_Replacement} +The optional @cite{Dot_Replacement} string is used to replace any periods +that occur in subunit or child unit names. If no @cite{Dot_Replacement} argument is used then separating dots appear unchanged in the resulting file name. Although the above syntax indicates that the -@code{Casing} argument must appear -before the @code{Dot_Replacement} argument, but it +@cite{Casing} argument must appear +before the @cite{Dot_Replacement} argument, but it is also permissible to write these arguments in the opposite order. As indicated, it is possible to specify different naming schemes for bodies, specs, and subunits. Quite often the rule for subunits is the same as the rule for bodies, in which case, there is no need to give -a separate @code{Subunit_File_Name} rule, and in this case the -@code{Body_File_name} rule is used for subunits as well. +a separate @cite{Subunit_File_Name} rule, and in this case the +@cite{Body_File_name} rule is used for subunits as well. The separate rule for subunits can also be used to implement the rather -unusual case of a compilation environment (e.g.@: a single directory) which +unusual case of a compilation environment (e.g., a single directory) which contains a subunit and a child unit with the same unit name. Although both units cannot appear in the same partition, the Ada Reference Manual allows (but does not require) the possibility of the two units coexisting @@ -1725,113 +2096,1236 @@ in the same environment. The file name translation works in the following steps: -@itemize @bullet -@item -If there is a specific @code{Source_File_Name} pragma for the given unit, +@itemize * + +@item +If there is a specific @cite{Source_File_Name} pragma for the given unit, then this is always used, and any general pattern rules are ignored. -@item -If there is a pattern type @code{Source_File_Name} pragma that applies to +@item +If there is a pattern type @cite{Source_File_Name} pragma that applies to the unit, then the resulting file name will be used if the file exists. If more than one pattern matches, the latest one will be tried first, and the first attempt resulting in a reference to a file that exists will be used. -@item -If no pattern type @code{Source_File_Name} pragma that applies to the unit +@item +If no pattern type @cite{Source_File_Name} pragma that applies to the unit for which the corresponding file exists, then the standard GNAT default naming rules are used. - @end itemize -@noindent As an example of the use of this mechanism, consider a commonly used scheme in which file names are all lower case, with separating periods copied -unchanged to the resulting file name, and specs end with @file{.1.ada}, and -bodies end with @file{.2.ada}. GNAT will follow this scheme if the following +unchanged to the resulting file name, and specs end with @code{.1.ada}, and +bodies end with @code{.2.ada}. GNAT will follow this scheme if the following two pragmas appear: -@smallexample @c ada -@b{pragma} Source_File_Name - (Spec_File_Name => "*.1.ada"); -@b{pragma} Source_File_Name - (Body_File_Name => "*.2.ada"); -@end smallexample +@example +pragma Source_File_Name + (Spec_File_Name => ".1.ada"); +pragma Source_File_Name + (Body_File_Name => ".2.ada"); +@end example -@noindent The default GNAT scheme is actually implemented by providing the following default pragmas internally: -@smallexample @c ada -@b{pragma} Source_File_Name - (Spec_File_Name => "*.ads", Dot_Replacement => "-"); -@b{pragma} Source_File_Name - (Body_File_Name => "*.adb", Dot_Replacement => "-"); -@end smallexample +@example +pragma Source_File_Name + (Spec_File_Name => ".ads", Dot_Replacement => "-"); +pragma Source_File_Name + (Body_File_Name => ".adb", Dot_Replacement => "-"); +@end example -@noindent Our final example implements a scheme typically used with one of the -Ada 83 compilers, where the separator character for subunits was ``__'' -(two underscores), specs were identified by adding @file{_.ADA}, bodies -by adding @file{.ADA}, and subunits by -adding @file{.SEP}. All file names were +Ada 83 compilers, where the separator character for subunits was '__' +(two underscores), specs were identified by adding @code{_.ADA}, bodies +by adding @code{.ADA}, and subunits by +adding @code{.SEP}. All file names were upper case. Child units were not present of course since this was an Ada 83 compiler, but it seems reasonable to extend this scheme to use the same double underscore separator for child units. -@smallexample @c ada -@b{pragma} Source_File_Name - (Spec_File_Name => "*_.ADA", +@example +pragma Source_File_Name + (Spec_File_Name => "_.ADA", Dot_Replacement => "__", Casing = Uppercase); -@b{pragma} Source_File_Name - (Body_File_Name => "*.ADA", +pragma Source_File_Name + (Body_File_Name => ".ADA", Dot_Replacement => "__", Casing = Uppercase); -@b{pragma} Source_File_Name - (Subunit_File_Name => "*.SEP", +pragma Source_File_Name + (Subunit_File_Name => ".SEP", Dot_Replacement => "__", Casing = Uppercase); -@end smallexample +@end example + +@geindex gnatname + +@node Handling Arbitrary File Naming Conventions with gnatname,File Name Krunching with gnatkr,Alternative File Naming Schemes,File Naming Topics and Utilities +@anchor{gnat_ugn/the_gnat_compilation_model handling-arbitrary-file-naming-conventions-with-gnatname}@anchor{5b}@anchor{gnat_ugn/the_gnat_compilation_model id12}@anchor{5c} +@subsection Handling Arbitrary File Naming Conventions with @cite{gnatname} + + +@geindex File Naming Conventions + +@menu +* Arbitrary File Naming Conventions:: +* Running gnatname:: +* Switches for gnatname:: +* Examples of gnatname Usage:: + +@end menu + +@node Arbitrary File Naming Conventions,Running gnatname,,Handling Arbitrary File Naming Conventions with gnatname +@anchor{gnat_ugn/the_gnat_compilation_model arbitrary-file-naming-conventions}@anchor{5d}@anchor{gnat_ugn/the_gnat_compilation_model id13}@anchor{5e} +@subsubsection Arbitrary File Naming Conventions + + +The GNAT compiler must be able to know the source file name of a compilation +unit. When using the standard GNAT default file naming conventions +(@cite{.ads} for specs, @cite{.adb} for bodies), the GNAT compiler +does not need additional information. + +When the source file names do not follow the standard GNAT default file naming +conventions, the GNAT compiler must be given additional information through +a configuration pragmas file (@ref{16,,Configuration Pragmas}) +or a project file. +When the non-standard file naming conventions are well-defined, +a small number of pragmas @cite{Source_File_Name} specifying a naming pattern +(@ref{5a,,Alternative File Naming Schemes}) may be sufficient. However, +if the file naming conventions are irregular or arbitrary, a number +of pragma @cite{Source_File_Name} for individual compilation units +must be defined. +To help maintain the correspondence between compilation unit names and +source file names within the compiler, +GNAT provides a tool @cite{gnatname} to generate the required pragmas for a +set of files. + +@node Running gnatname,Switches for gnatname,Arbitrary File Naming Conventions,Handling Arbitrary File Naming Conventions with gnatname +@anchor{gnat_ugn/the_gnat_compilation_model running-gnatname}@anchor{5f}@anchor{gnat_ugn/the_gnat_compilation_model id14}@anchor{60} +@subsubsection Running @cite{gnatname} + + +The usual form of the @cite{gnatname} command is: + +@example +$ gnatname [`switches`] `naming_pattern` [`naming_patterns`] + [--and [`switches`] `naming_pattern` [`naming_patterns`]] +@end example + +All of the arguments are optional. If invoked without any argument, +@cite{gnatname} will display its usage. + +When used with at least one naming pattern, @cite{gnatname} will attempt to +find all the compilation units in files that follow at least one of the +naming patterns. To find these compilation units, +@cite{gnatname} will use the GNAT compiler in syntax-check-only mode on all +regular files. + +One or several Naming Patterns may be given as arguments to @cite{gnatname}. +Each Naming Pattern is enclosed between double quotes (or single +quotes on Windows). +A Naming Pattern is a regular expression similar to the wildcard patterns +used in file names by the Unix shells or the DOS prompt. + +@cite{gnatname} may be called with several sections of directories/patterns. +Sections are separated by switch @cite{--and}. In each section, there must be +at least one pattern. If no directory is specified in a section, the current +directory (or the project directory is @cite{-P} is used) is implied. +The options other that the directory switches and the patterns apply globally +even if they are in different sections. + +Examples of Naming Patterns are: + +@example +"*.[12].ada" +"*.ad[sb]*" +"body_*" "spec_*" +@end example + +For a more complete description of the syntax of Naming Patterns, +see the second kind of regular expressions described in @code{g-regexp.ads} +(the 'Glob' regular expressions). + +When invoked with no switch @cite{-P}, @cite{gnatname} will create a +configuration pragmas file @code{gnat.adc} in the current working directory, +with pragmas @cite{Source_File_Name} for each file that contains a valid Ada +unit. + +@node Switches for gnatname,Examples of gnatname Usage,Running gnatname,Handling Arbitrary File Naming Conventions with gnatname +@anchor{gnat_ugn/the_gnat_compilation_model id15}@anchor{61}@anchor{gnat_ugn/the_gnat_compilation_model switches-for-gnatname}@anchor{62} +@subsubsection Switches for @cite{gnatname} + + +Switches for @cite{gnatname} must precede any specified Naming Pattern. + +You may specify any of the following switches to @cite{gnatname}: + +@geindex --version (gnatname) + + +@table @asis + +@item @code{--version} + +Display Copyright and version, then exit disregarding all other options. +@end table + +@geindex --help (gnatname) + + +@table @asis + +@item @code{--help} + +If @emph{--version} was not used, display usage, then exit disregarding +all other options. + +@item @code{--subdirs=@emph{dir}} + +Real object, library or exec directories are subdirectories <dir> of the +specified ones. + +@item @code{--no-backup} + +Do not create a backup copy of an existing project file. + +@item @code{--and} + +Start another section of directories/patterns. +@end table + +@geindex -c (gnatname) + + +@table @asis + +@item @code{-c@emph{filename}} + +Create a configuration pragmas file @code{filename} (instead of the default +@code{gnat.adc}). +There may be zero, one or more space between @emph{-c} and +@code{filename}. +@code{filename} may include directory information. @code{filename} must be +writable. There may be only one switch @emph{-c}. +When a switch @emph{-c} is +specified, no switch @emph{-P} may be specified (see below). +@end table + +@geindex -d (gnatname) + + +@table @asis + +@item @code{-d@emph{dir}} + +Look for source files in directory @code{dir}. There may be zero, one or more +spaces between @emph{-d} and @code{dir}. +@code{dir} may end with @cite{/**}, that is it may be of the form +@cite{root_dir/**}. In this case, the directory @cite{root_dir} and all of its +subdirectories, recursively, have to be searched for sources. +When a switch @emph{-d} +is specified, the current working directory will not be searched for source +files, unless it is explicitly specified with a @emph{-d} +or @emph{-D} switch. +Several switches @emph{-d} may be specified. +If @code{dir} is a relative path, it is relative to the directory of +the configuration pragmas file specified with switch +@emph{-c}, +or to the directory of the project file specified with switch +@emph{-P} or, +if neither switch @emph{-c} +nor switch @emph{-P} are specified, it is relative to the +current working directory. The directory +specified with switch @emph{-d} must exist and be readable. +@end table + +@geindex -D (gnatname) + + +@table @asis + +@item @code{-D@emph{filename}} + +Look for source files in all directories listed in text file @code{filename}. +There may be zero, one or more spaces between @emph{-D} +and @code{filename}. +@code{filename} must be an existing, readable text file. +Each nonempty line in @code{filename} must be a directory. +Specifying switch @emph{-D} is equivalent to specifying as many +switches @emph{-d} as there are nonempty lines in +@code{file}. + +@item @code{-eL} + +Follow symbolic links when processing project files. + +@geindex -f (gnatname) + +@item @code{-f@emph{pattern}} + +Foreign patterns. Using this switch, it is possible to add sources of languages +other than Ada to the list of sources of a project file. +It is only useful if a -P switch is used. +For example, + +@example +gnatname -Pprj -f"*.c" "*.ada" +@end example + +will look for Ada units in all files with the @code{.ada} extension, +and will add to the list of file for project @code{prj.gpr} the C files +with extension @code{.c}. + +@geindex -h (gnatname) + +@item @code{-h} + +Output usage (help) information. The output is written to @code{stdout}. + +@geindex -P (gnatname) + +@item @code{-P@emph{proj}} + +Create or update project file @code{proj}. There may be zero, one or more space +between @emph{-P} and @code{proj}. @code{proj} may include directory +information. @code{proj} must be writable. +There may be only one switch @emph{-P}. +When a switch @emph{-P} is specified, +no switch @emph{-c} may be specified. +On all platforms, except on VMS, when @cite{gnatname} is invoked for an +existing project file <proj>.gpr, a backup copy of the project file is created +in the project directory with file name <proj>.gpr.saved_x. 'x' is the first +non negative number that makes this backup copy a new file. + +@geindex -v (gnatname) + +@item @code{-v} + +Verbose mode. Output detailed explanation of behavior to @code{stdout}. +This includes name of the file written, the name of the directories to search +and, for each file in those directories whose name matches at least one of +the Naming Patterns, an indication of whether the file contains a unit, +and if so the name of the unit. +@end table + +@geindex -v -v (gnatname) + + +@table @asis + +@item @code{-v -v} + +Very Verbose mode. In addition to the output produced in verbose mode, +for each file in the searched directories whose name matches none of +the Naming Patterns, an indication is given that there is no match. + +@geindex -x (gnatname) + +@item @code{-x@emph{pattern}} + +Excluded patterns. Using this switch, it is possible to exclude some files +that would match the name patterns. For example, + +@example +gnatname -x "*_nt.ada" "*.ada" +@end example + +will look for Ada units in all files with the @code{.ada} extension, +except those whose names end with @code{_nt.ada}. +@end table + +@node Examples of gnatname Usage,,Switches for gnatname,Handling Arbitrary File Naming Conventions with gnatname +@anchor{gnat_ugn/the_gnat_compilation_model examples-of-gnatname-usage}@anchor{63}@anchor{gnat_ugn/the_gnat_compilation_model id16}@anchor{64} +@subsubsection Examples of @cite{gnatname} Usage + + +@example +$ gnatname -c /home/me/names.adc -d sources "[a-z]*.ada*" +@end example + +In this example, the directory @code{/home/me} must already exist +and be writable. In addition, the directory +@code{/home/me/sources} (specified by +@emph{-d sources}) must exist and be readable. + +Note the optional spaces after @emph{-c} and @emph{-d}. + +@example +$ gnatname -P/home/me/proj -x "*_nt_body.ada" +-dsources -dsources/plus -Dcommon_dirs.txt "body_*" "spec_*" +@end example + +Note that several switches @emph{-d} may be used, +even in conjunction with one or several switches +@emph{-D}. Several Naming Patterns and one excluded pattern +are used in this example. + +@node File Name Krunching with gnatkr,Renaming Files with gnatchop,Handling Arbitrary File Naming Conventions with gnatname,File Naming Topics and Utilities +@anchor{gnat_ugn/the_gnat_compilation_model file-name-krunching-with-gnatkr}@anchor{65}@anchor{gnat_ugn/the_gnat_compilation_model id17}@anchor{66} +@subsection File Name Krunching with @cite{gnatkr} + + +@geindex gnatkr + +This chapter discusses the method used by the compiler to shorten +the default file names chosen for Ada units so that they do not +exceed the maximum length permitted. It also describes the +@cite{gnatkr} utility that can be used to determine the result of +applying this shortening. + +@menu +* About gnatkr:: +* Using gnatkr:: +* Krunching Method:: +* Examples of gnatkr Usage:: + +@end menu + +@node About gnatkr,Using gnatkr,,File Name Krunching with gnatkr +@anchor{gnat_ugn/the_gnat_compilation_model id18}@anchor{67}@anchor{gnat_ugn/the_gnat_compilation_model about-gnatkr}@anchor{68} +@subsubsection About @cite{gnatkr} + + +The default file naming rule in GNAT +is that the file name must be derived from +the unit name. The exact default rule is as follows: + + +@itemize * + +@item +Take the unit name and replace all dots by hyphens. + +@item +If such a replacement occurs in the +second character position of a name, and the first character is +@code{a}, @code{g}, @code{s}, or @code{i}, +then replace the dot by the character +@code{~} (tilde) +instead of a minus. + +The reason for this exception is to avoid clashes +with the standard names for children of System, Ada, Interfaces, +and GNAT, which use the prefixes +@code{s-}, @code{a-}, @code{i-}, and @code{g-}, +respectively. +@end itemize + +The @code{-gnatk@emph{nn}} +switch of the compiler activates a 'krunching' +circuit that limits file names to nn characters (where nn is a decimal +integer). + +The @cite{gnatkr} utility can be used to determine the krunched name for +a given file, when krunched to a specified maximum length. + +@node Using gnatkr,Krunching Method,About gnatkr,File Name Krunching with gnatkr +@anchor{gnat_ugn/the_gnat_compilation_model id19}@anchor{69}@anchor{gnat_ugn/the_gnat_compilation_model using-gnatkr}@anchor{56} +@subsubsection Using @cite{gnatkr} + + +The @cite{gnatkr} command has the form: + +@example +$ gnatkr `name` [`length`] +@end example + +@cite{name} is the uncrunched file name, derived from the name of the unit +in the standard manner described in the previous section (i.e., in particular +all dots are replaced by hyphens). The file name may or may not have an +extension (defined as a suffix of the form period followed by arbitrary +characters other than period). If an extension is present then it will +be preserved in the output. For example, when krunching @code{hellofile.ads} +to eight characters, the result will be hellofil.ads. + +Note: for compatibility with previous versions of @cite{gnatkr} dots may +appear in the name instead of hyphens, but the last dot will always be +taken as the start of an extension. So if @cite{gnatkr} is given an argument +such as @code{Hello.World.adb} it will be treated exactly as if the first +period had been a hyphen, and for example krunching to eight characters +gives the result @code{hellworl.adb}. + +Note that the result is always all lower case. +Characters of the other case are folded as required. + +@cite{length} represents the length of the krunched name. The default +when no argument is given is 8 characters. A length of zero stands for +unlimited, in other words do not chop except for system files where the +implied crunching length is always eight characters. + +The output is the krunched name. The output has an extension only if the +original argument was a file name with an extension. + +@node Krunching Method,Examples of gnatkr Usage,Using gnatkr,File Name Krunching with gnatkr +@anchor{gnat_ugn/the_gnat_compilation_model id20}@anchor{6a}@anchor{gnat_ugn/the_gnat_compilation_model krunching-method}@anchor{6b} +@subsubsection Krunching Method + + +The initial file name is determined by the name of the unit that the file +contains. The name is formed by taking the full expanded name of the +unit and replacing the separating dots with hyphens and +using lowercase +for all letters, except that a hyphen in the second character position is +replaced by a tilde if the first character is +@code{a}, @code{i}, @code{g}, or @code{s}. +The extension is @cite{.ads} for a +spec and @cite{.adb} for a body. +Krunching does not affect the extension, but the file name is shortened to +the specified length by following these rules: + + +@itemize * + +@item +The name is divided into segments separated by hyphens, tildes or +underscores and all hyphens, tildes, and underscores are +eliminated. If this leaves the name short enough, we are done. + +@item +If the name is too long, the longest segment is located (left-most +if there are two of equal length), and shortened by dropping +its last character. This is repeated until the name is short enough. + +As an example, consider the krunching of @code{our-strings-wide_fixed.adb} +to fit the name into 8 characters as required by some operating systems: + +@example +our-strings-wide_fixed 22 +our strings wide fixed 19 +our string wide fixed 18 +our strin wide fixed 17 +our stri wide fixed 16 +our stri wide fixe 15 +our str wide fixe 14 +our str wid fixe 13 +our str wid fix 12 +ou str wid fix 11 +ou st wid fix 10 +ou st wi fix 9 +ou st wi fi 8 +Final file name: oustwifi.adb +@end example + +@item +The file names for all predefined units are always krunched to eight +characters. The krunching of these predefined units uses the following +special prefix replacements: + + +@multitable {xxxxxxxxxxxxxxxxxxxxxxx} {xxxxxxxxxxxxxxxx} +@item + +Prefix + +@tab + +Replacement + +@item + +@code{ada-} + +@tab + +@code{a-} + +@item + +@code{gnat-} + +@tab + +@code{g-} + +@item + +@code{interfac es-} + +@tab + +@code{i-} + +@item + +@code{system-} + +@tab + +@code{s-} + +@end multitable + + +These system files have a hyphen in the second character position. That +is why normal user files replace such a character with a +tilde, to avoid confusion with system file names. + +As an example of this special rule, consider +@code{ada-strings-wide_fixed.adb}, which gets krunched as follows: + +@example +ada-strings-wide_fixed 22 +a- strings wide fixed 18 +a- string wide fixed 17 +a- strin wide fixed 16 +a- stri wide fixed 15 +a- stri wide fixe 14 +a- str wide fixe 13 +a- str wid fixe 12 +a- str wid fix 11 +a- st wid fix 10 +a- st wi fix 9 +a- st wi fi 8 +Final file name: a-stwifi.adb +@end example +@end itemize + +Of course no file shortening algorithm can guarantee uniqueness over all +possible unit names, and if file name krunching is used then it is your +responsibility to ensure that no name clashes occur. The utility +program @cite{gnatkr} is supplied for conveniently determining the +krunched name of a file. + +@node Examples of gnatkr Usage,,Krunching Method,File Name Krunching with gnatkr +@anchor{gnat_ugn/the_gnat_compilation_model id21}@anchor{6c}@anchor{gnat_ugn/the_gnat_compilation_model examples-of-gnatkr-usage}@anchor{6d} +@subsubsection Examples of @cite{gnatkr} Usage + + +@example +$ gnatkr very_long_unit_name.ads --> velounna.ads +$ gnatkr grandparent-parent-child.ads --> grparchi.ads +$ gnatkr Grandparent.Parent.Child.ads --> grparchi.ads +$ gnatkr grandparent-parent-child --> grparchi +$ gnatkr very_long_unit_name.ads/count=6 --> vlunna.ads +$ gnatkr very_long_unit_name.ads/count=0 --> very_long_unit_name.ads +@end example + +@node Renaming Files with gnatchop,,File Name Krunching with gnatkr,File Naming Topics and Utilities +@anchor{gnat_ugn/the_gnat_compilation_model id22}@anchor{6e}@anchor{gnat_ugn/the_gnat_compilation_model renaming-files-with-gnatchop}@anchor{38} +@subsection Renaming Files with @cite{gnatchop} + + +@geindex gnatchop + +This chapter discusses how to handle files with multiple units by using +the @cite{gnatchop} utility. This utility is also useful in renaming +files to meet the standard GNAT default file naming conventions. + +@menu +* Handling Files with Multiple Units:: +* Operating gnatchop in Compilation Mode:: +* Command Line for gnatchop:: +* Switches for gnatchop:: +* Examples of gnatchop Usage:: + +@end menu + +@node Handling Files with Multiple Units,Operating gnatchop in Compilation Mode,,Renaming Files with gnatchop +@anchor{gnat_ugn/the_gnat_compilation_model id23}@anchor{6f}@anchor{gnat_ugn/the_gnat_compilation_model handling-files-with-multiple-units}@anchor{70} +@subsubsection Handling Files with Multiple Units + + +The basic compilation model of GNAT requires that a file submitted to the +compiler have only one unit and there be a strict correspondence +between the file name and the unit name. + +The @cite{gnatchop} utility allows both of these rules to be relaxed, +allowing GNAT to process files which contain multiple compilation units +and files with arbitrary file names. @cite{gnatchop} +reads the specified file and generates one or more output files, +containing one unit per file. The unit and the file name correspond, +as required by GNAT. + +If you want to permanently restructure a set of 'foreign' files so that +they match the GNAT rules, and do the remaining development using the +GNAT structure, you can simply use @emph{gnatchop} once, generate the +new set of files and work with them from that point on. + +Alternatively, if you want to keep your files in the 'foreign' format, +perhaps to maintain compatibility with some other Ada compilation +system, you can set up a procedure where you use @emph{gnatchop} each +time you compile, regarding the source files that it writes as temporary +files that you throw away. + +Note that if your file containing multiple units starts with a byte order +mark (BOM) specifying UTF-8 encoding, then the files generated by gnatchop +will each start with a copy of this BOM, meaning that they can be compiled +automatically in UTF-8 mode without needing to specify an explicit encoding. + +@node Operating gnatchop in Compilation Mode,Command Line for gnatchop,Handling Files with Multiple Units,Renaming Files with gnatchop +@anchor{gnat_ugn/the_gnat_compilation_model operating-gnatchop-in-compilation-mode}@anchor{71}@anchor{gnat_ugn/the_gnat_compilation_model id24}@anchor{72} +@subsubsection Operating gnatchop in Compilation Mode + + +The basic function of @cite{gnatchop} is to take a file with multiple units +and split it into separate files. The boundary between files is reasonably +clear, except for the issue of comments and pragmas. In default mode, the +rule is that any pragmas between units belong to the previous unit, except +that configuration pragmas always belong to the following unit. Any comments +belong to the following unit. These rules +almost always result in the right choice of +the split point without needing to mark it explicitly and most users will +find this default to be what they want. In this default mode it is incorrect to +submit a file containing only configuration pragmas, or one that ends in +configuration pragmas, to @cite{gnatchop}. + +However, using a special option to activate 'compilation mode', +@cite{gnatchop} +can perform another function, which is to provide exactly the semantics +required by the RM for handling of configuration pragmas in a compilation. +In the absence of configuration pragmas (at the main file level), this +option has no effect, but it causes such configuration pragmas to be handled +in a quite different manner. + +First, in compilation mode, if @cite{gnatchop} is given a file that consists of +only configuration pragmas, then this file is appended to the +@code{gnat.adc} file in the current directory. This behavior provides +the required behavior described in the RM for the actions to be taken +on submitting such a file to the compiler, namely that these pragmas +should apply to all subsequent compilations in the same compilation +environment. Using GNAT, the current directory, possibly containing a +@code{gnat.adc} file is the representation +of a compilation environment. For more information on the +@code{gnat.adc} file, see @ref{58,,Handling of Configuration Pragmas}. + +Second, in compilation mode, if @cite{gnatchop} +is given a file that starts with +configuration pragmas, and contains one or more units, then these +configuration pragmas are prepended to each of the chopped files. This +behavior provides the required behavior described in the RM for the +actions to be taken on compiling such a file, namely that the pragmas +apply to all units in the compilation, but not to subsequently compiled +units. + +Finally, if configuration pragmas appear between units, they are appended +to the previous unit. This results in the previous unit being illegal, +since the compiler does not accept configuration pragmas that follow +a unit. This provides the required RM behavior that forbids configuration +pragmas other than those preceding the first compilation unit of a +compilation. + +For most purposes, @cite{gnatchop} will be used in default mode. The +compilation mode described above is used only if you need exactly +accurate behavior with respect to compilations, and you have files +that contain multiple units and configuration pragmas. In this +circumstance the use of @cite{gnatchop} with the compilation mode +switch provides the required behavior, and is for example the mode +in which GNAT processes the ACVC tests. + +@node Command Line for gnatchop,Switches for gnatchop,Operating gnatchop in Compilation Mode,Renaming Files with gnatchop +@anchor{gnat_ugn/the_gnat_compilation_model id25}@anchor{73}@anchor{gnat_ugn/the_gnat_compilation_model command-line-for-gnatchop}@anchor{74} +@subsubsection Command Line for @cite{gnatchop} + + +The @cite{gnatchop} command has the form: + +@example +$ gnatchop switches file_name [file_name ...] + [directory] +@end example + +The only required argument is the file name of the file to be chopped. +There are no restrictions on the form of this file name. The file itself +contains one or more Ada units, in normal GNAT format, concatenated +together. As shown, more than one file may be presented to be chopped. + +When run in default mode, @cite{gnatchop} generates one output file in +the current directory for each unit in each of the files. + +@cite{directory}, if specified, gives the name of the directory to which +the output files will be written. If it is not specified, all files are +written to the current directory. + +For example, given a +file called @code{hellofiles} containing + +@example +procedure Hello; + +with Ada.Text_IO; use Ada.Text_IO; +procedure Hello is +begin + Put_Line ("Hello"); +end Hello; +@end example + +the command + +@example +$ gnatchop hellofiles +@end example + +generates two files in the current directory, one called +@code{hello.ads} containing the single line that is the procedure spec, +and the other called @code{hello.adb} containing the remaining text. The +original file is not affected. The generated files can be compiled in +the normal manner. + +When gnatchop is invoked on a file that is empty or that contains only empty +lines and/or comments, gnatchop will not fail, but will not produce any +new sources. + +For example, given a +file called @code{toto.txt} containing + +@example +-- Just a comment +@end example + +the command + +@example +$ gnatchop toto.txt +@end example + +will not produce any new file and will result in the following warnings: + +@example +toto.txt:1:01: warning: empty file, contains no compilation units +no compilation units found +no source files written +@end example + +@node Switches for gnatchop,Examples of gnatchop Usage,Command Line for gnatchop,Renaming Files with gnatchop +@anchor{gnat_ugn/the_gnat_compilation_model switches-for-gnatchop}@anchor{75}@anchor{gnat_ugn/the_gnat_compilation_model id26}@anchor{76} +@subsubsection Switches for @cite{gnatchop} + + +@emph{gnatchop} recognizes the following switches: + +@geindex --version (gnatchop) + + +@table @asis + +@item @code{--version} + +Display Copyright and version, then exit disregarding all other options. +@end table + +@geindex --help (gnatchop) + + +@table @asis + +@item @code{--help} + +If @emph{--version} was not used, display usage, then exit disregarding +all other options. +@end table + +@geindex -c (gnatchop) + + +@table @asis + +@item @code{-c} + +Causes @cite{gnatchop} to operate in compilation mode, in which +configuration pragmas are handled according to strict RM rules. See +previous section for a full description of this mode. + +@item @code{-gnat@emph{xxx}} + +This passes the given @emph{-gnat`xxx*` switch to `gnat` which is +used to parse the given file. Not all `xxx` options make sense, +but for example, the use of *-gnati2} allows @cite{gnatchop} to +process a source file that uses Latin-2 coding for identifiers. + +@item @code{-h} + +Causes @cite{gnatchop} to generate a brief help summary to the standard +output file showing usage information. +@end table + +@geindex -k (gnatchop) + + +@table @asis + +@item @code{-k@emph{mm}} + +Limit generated file names to the specified number @cite{mm} +of characters. +This is useful if the +resulting set of files is required to be interoperable with systems +which limit the length of file names. +No space is allowed between the @emph{-k} and the numeric value. The numeric +value may be omitted in which case a default of @emph{-k8}, +suitable for use +with DOS-like file systems, is used. If no @emph{-k} switch +is present then +there is no limit on the length of file names. +@end table + +@geindex -p (gnatchop) + + +@table @asis + +@item @code{-p} + +Causes the file modification time stamp of the input file to be +preserved and used for the time stamp of the output file(s). This may be +useful for preserving coherency of time stamps in an environment where +@cite{gnatchop} is used as part of a standard build process. +@end table + +@geindex -q (gnatchop) -@node Generating Object Files + +@table @asis + +@item @code{-q} + +Causes output of informational messages indicating the set of generated +files to be suppressed. Warnings and error messages are unaffected. +@end table + +@geindex -r (gnatchop) + +@geindex Source_Reference pragmas + + +@table @asis + +@item @code{-r} + +Generate @cite{Source_Reference} pragmas. Use this switch if the output +files are regarded as temporary and development is to be done in terms +of the original unchopped file. This switch causes +@cite{Source_Reference} pragmas to be inserted into each of the +generated files to refers back to the original file name and line number. +The result is that all error messages refer back to the original +unchopped file. +In addition, the debugging information placed into the object file (when +the @emph{-g} switch of @emph{gcc} or @emph{gnatmake} is +specified) +also refers back to this original file so that tools like profilers and +debuggers will give information in terms of the original unchopped file. + +If the original file to be chopped itself contains +a @cite{Source_Reference} +pragma referencing a third file, then gnatchop respects +this pragma, and the generated @cite{Source_Reference} pragmas +in the chopped file refer to the original file, with appropriate +line numbers. This is particularly useful when @cite{gnatchop} +is used in conjunction with @cite{gnatprep} to compile files that +contain preprocessing statements and multiple units. +@end table + +@geindex -v (gnatchop) + + +@table @asis + +@item @code{-v} + +Causes @cite{gnatchop} to operate in verbose mode. The version +number and copyright notice are output, as well as exact copies of +the gnat1 commands spawned to obtain the chop control information. +@end table + +@geindex -w (gnatchop) + + +@table @asis + +@item @code{-w} + +Overwrite existing file names. Normally @cite{gnatchop} regards it as a +fatal error if there is already a file with the same name as a +file it would otherwise output, in other words if the files to be +chopped contain duplicated units. This switch bypasses this +check, and causes all but the last instance of such duplicated +units to be skipped. +@end table + +@geindex --GCC= (gnatchop) + + +@table @asis + +@item @code{--GCC=@emph{xxxx}} + +Specify the path of the GNAT parser to be used. When this switch is used, +no attempt is made to add the prefix to the GNAT parser executable. +@end table + +@node Examples of gnatchop Usage,,Switches for gnatchop,Renaming Files with gnatchop +@anchor{gnat_ugn/the_gnat_compilation_model id27}@anchor{77}@anchor{gnat_ugn/the_gnat_compilation_model examples-of-gnatchop-usage}@anchor{78} +@subsubsection Examples of @cite{gnatchop} Usage + + +@example +$ gnatchop -w hello_s.ada prerelease/files +@end example + +Chops the source file @code{hello_s.ada}. The output files will be +placed in the directory @code{prerelease/files}, +overwriting any +files with matching names in that directory (no files in the current +directory are modified). + +@example +$ gnatchop archive +@end example + +Chops the source file @code{archive} +into the current directory. One +useful application of @cite{gnatchop} is in sending sets of sources +around, for example in email messages. The required sources are simply +concatenated (for example, using a Unix @cite{cat} +command), and then +@emph{gnatchop} is used at the other end to reconstitute the original +file names. + +@example +$ gnatchop file1 file2 file3 direc +@end example + +Chops all units in files @code{file1}, @code{file2}, @code{file3}, placing +the resulting files in the directory @code{direc}. Note that if any units +occur more than once anywhere within this set of files, an error message +is generated, and no files are written. To override this check, use the +@emph{-w} switch, +in which case the last occurrence in the last file will +be the one that is output, and earlier duplicate occurrences for a given +unit will be skipped. + +@node Configuration Pragmas,Generating Object Files,File Naming Topics and Utilities,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model id28}@anchor{79}@anchor{gnat_ugn/the_gnat_compilation_model configuration-pragmas}@anchor{16} +@section Configuration Pragmas + + +@geindex Configuration pragmas + +@geindex Pragmas +@geindex configuration + +Configuration pragmas include those pragmas described as +such in the Ada Reference Manual, as well as +implementation-dependent pragmas that are configuration pragmas. +See the @cite{Implementation_Defined_Pragmas} chapter in the +@cite{GNAT_Reference_Manual} for details on these +additional GNAT-specific configuration pragmas. +Most notably, the pragma @cite{Source_File_Name}, which allows +specifying non-default names for source files, is a configuration +pragma. The following is a complete list of configuration pragmas +recognized by GNAT: + +@example +Ada_83 +Ada_95 +Ada_05 +Ada_2005 +Ada_12 +Ada_2012 +Allow_Integer_Address +Annotate +Assertion_Policy +Assume_No_Invalid_Values +C_Pass_By_Copy +Check_Name +Check_Policy +Compile_Time_Error +Compile_Time_Warning +Compiler_Unit +Component_Alignment +Convention_Identifier +Debug_Policy +Detect_Blocking +Default_Storage_Pool +Discard_Names +Elaboration_Checks +Eliminate +Extend_System +Extensions_Allowed +External_Name_Casing +Fast_Math +Favor_Top_Level +Float_Representation +Implicit_Packing +Initialize_Scalars +Interrupt_State +License +Locking_Policy +Long_Float +No_Run_Time +No_Strict_Aliasing +Normalize_Scalars +Optimize_Alignment +Persistent_BSS +Polling +Priority_Specific_Dispatching +Profile +Profile_Warnings +Propagate_Exceptions +Queuing_Policy +Ravenscar +Restricted_Run_Time +Restrictions +Restrictions_Warnings +Reviewable +Short_Circuit_And_Or +Source_File_Name +Source_File_Name_Project +SPARK_Mode +Style_Checks +Suppress +Suppress_Exception_Locations +Task_Dispatching_Policy +Universal_Data +Unsuppress +Use_VADS_Size +Validity_Checks +Warnings +Wide_Character_Encoding +@end example + +@menu +* Handling of Configuration Pragmas:: +* The Configuration Pragmas Files:: + +@end menu + +@node Handling of Configuration Pragmas,The Configuration Pragmas Files,,Configuration Pragmas +@anchor{gnat_ugn/the_gnat_compilation_model id29}@anchor{7a}@anchor{gnat_ugn/the_gnat_compilation_model handling-of-configuration-pragmas}@anchor{58} +@subsection Handling of Configuration Pragmas + + +Configuration pragmas may either appear at the start of a compilation +unit, or they can appear in a configuration pragma file to apply to +all compilations performed in a given compilation environment. + +GNAT also provides the @cite{gnatchop} utility to provide an automatic +way to handle configuration pragmas following the semantics for +compilations (that is, files with multiple units), described in the RM. +See @ref{71,,Operating gnatchop in Compilation Mode} for details. +However, for most purposes, it will be more convenient to edit the +@code{gnat.adc} file that contains configuration pragmas directly, +as described in the following section. + +In the case of @cite{Restrictions} pragmas appearing as configuration +pragmas in individual compilation units, the exact handling depends on +the type of restriction. + +Restrictions that require partition-wide consistency (like +@cite{No_Tasking}) are +recognized wherever they appear +and can be freely inherited, e.g. from a @emph{with}ed unit to the @emph{with}ing +unit. This makes sense since the binder will in any case insist on seeing +consistent use, so any unit not conforming to any restrictions that are +anywhere in the partition will be rejected, and you might as well find +that out at compile time rather than at bind time. + +For restrictions that do not require partition-wide consistency, e.g. +SPARK or No_Implementation_Attributes, in general the restriction applies +only to the unit in which the pragma appears, and not to any other units. + +The exception is No_Elaboration_Code which always applies to the entire +object file from a compilation, i.e. to the body, spec, and all subunits. +This restriction can be specified in a configuration pragma file, or it +can be on the body and/or the spec (in eithe case it applies to all the +relevant units). It can appear on a subunit only if it has previously +appeared in the body of spec. + +@node The Configuration Pragmas Files,,Handling of Configuration Pragmas,Configuration Pragmas +@anchor{gnat_ugn/the_gnat_compilation_model the-configuration-pragmas-files}@anchor{7b}@anchor{gnat_ugn/the_gnat_compilation_model id30}@anchor{7c} +@subsection The Configuration Pragmas Files + + +@geindex gnat.adc + +In GNAT a compilation environment is defined by the current +directory at the time that a compile command is given. This current +directory is searched for a file whose name is @code{gnat.adc}. If +this file is present, it is expected to contain one or more +configuration pragmas that will be applied to the current compilation. +However, if the switch @emph{-gnatA} is used, @code{gnat.adc} is not +considered. When taken into account, @code{gnat.adc} is added to the +dependencies, so that if @code{gnat.adc} is modified later, an invocation of +@emph{gnatmake} will recompile the source. + +Configuration pragmas may be entered into the @code{gnat.adc} file +either by running @cite{gnatchop} on a source file that consists only of +configuration pragmas, or more conveniently by direct editing of the +@code{gnat.adc} file, which is a standard format source file. + +Besides @code{gnat.adc}, additional files containing configuration +pragmas may be applied to the current compilation using the switch +@code{-gnatec=@emph{path}} where @cite{path} must designate an existing file that +contains only configuration pragmas. These configuration pragmas are +in addition to those found in @code{gnat.adc} (provided @code{gnat.adc} +is present and switch @emph{-gnatA} is not used). + +It is allowable to specify several switches @emph{-gnatec=}, all of which +will be taken into account. + +Files containing configuration pragmas specified with switches +@emph{-gnatec=} are added to the dependencies, unless they are +temporary files. A file is considered temporary if its name ends in +@code{.tmp} or @code{.TMP}. Certain tools follow this naming +convention because they pass information to @emph{gcc} via +temporary files that are immediately deleted; it doesn't make sense to +depend on a file that no longer exists. Such tools include +@emph{gprbuild}, @emph{gnatmake}, and @emph{gnatcheck}. + +If you are using project file, a separate mechanism is provided using +project attributes, see @ref{7d,,Specifying Configuration Pragmas} for more +details. + +@node Generating Object Files,Source Dependencies,Configuration Pragmas,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model generating-object-files}@anchor{42}@anchor{gnat_ugn/the_gnat_compilation_model id31}@anchor{7e} @section Generating Object Files -@noindent + An Ada program consists of a set of source files, and the first step in compiling the program is to generate the corresponding object files. These are generated by compiling a subset of these source files. The files you need to compile are the following: -@itemize @bullet -@item + +@itemize * + +@item If a package spec has no body, compile the package spec to produce the object file for the package. -@item +@item If a package has both a spec and a body, compile the body to produce the object file for the package. The source file for the package spec need not be compiled in this case because there is only one object file, which contains the code for both the spec and body of the package. -@item +@item For a subprogram, compile the subprogram body to produce the object file for the subprogram. The spec, if one is present, is as usual in a separate file, and need not be compiled. +@end itemize -@item -@cindex Subunits +@geindex Subunits + + +@itemize * + +@item In the case of subunits, only compile the parent unit. A single object file is generated for the entire subunit tree, which includes all the subunits. -@item +@item Compile child units independently of their parent units (though, of course, the spec of all the ancestor unit must be present in order to compile a child unit). -@item -@cindex Generics +@geindex Generics + +@item Compile generic units in the same manner as any other units. The object files in this case are small dummy files that contain at most the flag used for elaboration checking. This is because GNAT always handles generic @@ -1839,11 +3333,10 @@ instantiation by means of macro expansion. However, it is still necessary to compile generic units, for dependency checking and elaboration purposes. @end itemize -@noindent The preceding rules describe the set of files that must be compiled to generate the object files for a program. Each object file has the same name as the corresponding source file, except that the extension is -@file{.o} as usual. +@code{.o} as usual. You may wish to compile other files for the purpose of checking their syntactic and semantic correctness. For example, in the case where a @@ -1855,78 +3348,87 @@ compilations will fail if there is an error in the spec. GNAT provides an option for compiling such files purely for the purposes of checking correctness; such compilations are not required as part of the process of building a program. To compile a file in this -checking mode, use the @option{-gnatc} switch. +checking mode, use the @emph{-gnatc} switch. -@node Source Dependencies +@node Source Dependencies,The Ada Library Information Files,Generating Object Files,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model id32}@anchor{7f}@anchor{gnat_ugn/the_gnat_compilation_model source-dependencies}@anchor{43} @section Source Dependencies -@noindent + A given object file clearly depends on the source file which is compiled -to produce it. Here we are using @dfn{depends} in the sense of a typical -@code{make} utility; in other words, an object file depends on a source +to produce it. Here we are using "depends" in the sense of a typical +@cite{make} utility; in other words, an object file depends on a source file if changes to the source file require the object file to be recompiled. In addition to this basic dependency, a given object may depend on additional source files as follows: -@itemize @bullet -@item -If a file being compiled @code{with}'s a unit @var{X}, the object file -depends on the file containing the spec of unit @var{X}. This includes -files that are @code{with}'ed implicitly either because they are parents -of @code{with}'ed child units or they are run-time units required by the + +@itemize * + +@item +If a file being compiled @emph{with}s a unit @cite{X}, the object file +depends on the file containing the spec of unit @cite{X}. This includes +files that are @emph{with}ed implicitly either because they are parents +of @emph{with}ed child units or they are run-time units required by the language constructs used in a particular unit. -@item +@item If a file being compiled instantiates a library level generic unit, the object file depends on both the spec and body files for this generic unit. -@item +@item If a file being compiled instantiates a generic unit defined within a package, the object file depends on the body file for the package as well as the spec file. +@end itemize -@item -@findex Inline -@cindex @option{-gnatn} switch +@geindex Inline + +@geindex -gnatn switch + + +@itemize * + +@item If a file being compiled contains a call to a subprogram for which -pragma @code{Inline} applies and inlining is activated with the -@option{-gnatn} switch, the object file depends on the file containing the +pragma @cite{Inline} applies and inlining is activated with the +@emph{-gnatn} switch, the object file depends on the file containing the body of this subprogram as well as on the file containing the spec. Note that for inlining to actually occur as a result of the use of this switch, it is necessary to compile in optimizing mode. -@cindex @option{-gnatN} switch -The use of @option{-gnatN} activates inlining optimization +@geindex -gnatN switch + +The use of @emph{-gnatN} activates inlining optimization that is performed by the front end of the compiler. This inlining does -not require that the code generation be optimized. Like @option{-gnatn}, +not require that the code generation be optimized. Like @emph{-gnatn}, the use of this switch generates additional dependencies. When using a gcc-based back end (in practice this means using any version -of GNAT other than the JGNAT, .NET or GNAAMP versions), then the use of -@option{-gnatN} is deprecated, and the use of @option{-gnatn} is preferred. +of GNAT other than for the JVM, .NET or GNAAMP platforms), then the use of +@emph{-gnatN} is deprecated, and the use of @emph{-gnatn} is preferred. Historically front end inlining was more extensive than the gcc back end inlining, but that is no longer the case. -@item -If an object file @file{O} depends on the proper body of a subunit through +@item +If an object file @code{O} depends on the proper body of a subunit through inlining or instantiation, it depends on the parent unit of the subunit. This means that any modification of the parent unit or one of its subunits -affects the compilation of @file{O}. +affects the compilation of @code{O}. -@item +@item The object file for a parent unit depends on all its subunit body files. -@item +@item The previous two rules meant that for purposes of computing dependencies and recompilation, a body and all its subunits are treated as an indivisible whole. -@noindent -These rules are applied transitively: if unit @code{A} @code{with}'s -unit @code{B}, whose elaboration calls an inlined procedure in package -@code{C}, the object file for unit @code{A} will depend on the body of -@code{C}, in file @file{c.adb}. +These rules are applied transitively: if unit @cite{A} @emph{with}s +unit @cite{B}, whose elaboration calls an inlined procedure in package +@cite{C}, the object file for unit @cite{A} will depend on the body of +@cite{C}, in file @code{c.adb}. The set of dependent files described by these rules includes all the files on which the unit is semantically dependent, as dictated by the @@ -1936,82 +3438,86 @@ dependencies. An object file must be recreated by recompiling the corresponding source file if any of the source files on which it depends are modified. For -example, if the @code{make} utility is used to control compilation, +example, if the @cite{make} utility is used to control compilation, the rule for an Ada object file must mention all the source files on which the object file depends, according to the above definition. The determination of the necessary -recompilations is done automatically when one uses @command{gnatmake}. +recompilations is done automatically when one uses @emph{gnatmake}. @end itemize -@node The Ada Library Information Files +@node The Ada Library Information Files,Binding an Ada Program,Source Dependencies,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model id33}@anchor{80}@anchor{gnat_ugn/the_gnat_compilation_model the-ada-library-information-files}@anchor{44} @section The Ada Library Information Files -@cindex Ada Library Information files -@cindex @file{ALI} files -@noindent + +@geindex Ada Library Information files + +@geindex ALI files + Each compilation actually generates two output files. The first of these -is the normal object file that has a @file{.o} extension. The second is a +is the normal object file that has a @code{.o} extension. The second is a text file containing full dependency information. It has the same -name as the source file, but an @file{.ali} extension. -This file is known as the Ada Library Information (@file{ALI}) file. -The following information is contained in the @file{ALI} file. +name as the source file, but an @code{.ali} extension. +This file is known as the Ada Library Information (@code{ALI}) file. +The following information is contained in the @code{ALI} file. -@itemize @bullet -@item + +@itemize * + +@item Version information (indicates which version of GNAT was used to compile the unit(s) in question) -@item +@item Main program information (including priority and time slice settings, as well as the wide character encoding used during compilation). -@item -List of arguments used in the @command{gcc} command for the compilation +@item +List of arguments used in the @emph{gcc} command for the compilation -@item +@item Attributes of the unit, including configuration pragmas used, an indication of whether the compilation was successful, exception model used etc. -@item +@item A list of relevant restrictions applying to the unit (used for consistency) checking. -@item -Categorization information (e.g.@: use of pragma @code{Pure}). +@item +Categorization information (e.g., use of pragma @cite{Pure}). -@item -Information on all @code{with}'ed units, including presence of -@code{Elaborate} or @code{Elaborate_All} pragmas. +@item +Information on all @emph{with}ed units, including presence of +Elaborate` or @cite{Elaborate_All} pragmas. -@item -Information from any @code{Linker_Options} pragmas used in the unit +@item +Information from any @cite{Linker_Options} pragmas used in the unit -@item -Information on the use of @code{Body_Version} or @code{Version} +@item +Information on the use of @cite{Body_Version} or @cite{Version} attributes in the unit. -@item +@item Dependency information. This is a list of files, together with time stamp and checksum information. These are files on which the unit depends in the sense that recompilation is required if any of these units are modified. -@item +@item Cross-reference data. Contains information on all entities referenced -in the unit. Used by tools like @code{gnatxref} and @code{gnatfind} to +in the unit. Used by tools like @cite{gnatxref} and @cite{gnatfind} to provide cross-reference information. - @end itemize -@noindent -For a full detailed description of the format of the @file{ALI} file, -see the source of the body of unit @code{Lib.Writ}, contained in file -@file{lib-writ.adb} in the GNAT compiler sources. +For a full detailed description of the format of the @code{ALI} file, +see the source of the body of unit @cite{Lib.Writ}, contained in file +@code{lib-writ.adb} in the GNAT compiler sources. -@node Binding an Ada Program +@node Binding an Ada Program,GNAT and Libraries,The Ada Library Information Files,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model id34}@anchor{81}@anchor{gnat_ugn/the_gnat_compilation_model binding-an-ada-program}@anchor{45} @section Binding an Ada Program -@noindent + When using languages such as C and C++, once the source files have been compiled the only remaining step in building an executable program is linking the object modules together. This means that it is possible to @@ -2035,34 +3541,1739 @@ default, that contains calls to the elaboration procedures of those compilation unit that require them, followed by a call to the main program. This Ada program is compiled to generate the object file for the main program. The name of -the Ada file is @file{b~@var{xxx}.adb} (with the corresponding spec -@file{b~@var{xxx}.ads}) where @var{xxx} is the name of the +the Ada file is @code{b~xxx}.adb` (with the corresponding spec +@code{b~xxx}.ads`) where @cite{xxx} is the name of the main program unit. Finally, the linker is used to build the resulting executable program, using the object from the main program from the bind step as well as the object files for the Ada units of the program. -@node Mixed Language Programming +@node GNAT and Libraries,Conditional Compilation,Binding an Ada Program,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model gnat-and-libraries}@anchor{17}@anchor{gnat_ugn/the_gnat_compilation_model id35}@anchor{82} +@section GNAT and Libraries + + +@geindex Library building and using + +This chapter describes how to build and use libraries with GNAT, and also shows +how to recompile the GNAT run-time library. You should be familiar with the +Project Manager facility (@ref{b,,GNAT Project Manager}) before reading this +chapter. + +@menu +* Introduction to Libraries in GNAT:: +* General Ada Libraries:: +* Stand-alone Ada Libraries:: +* Rebuilding the GNAT Run-Time Library:: + +@end menu + +@node Introduction to Libraries in GNAT,General Ada Libraries,,GNAT and Libraries +@anchor{gnat_ugn/the_gnat_compilation_model introduction-to-libraries-in-gnat}@anchor{83}@anchor{gnat_ugn/the_gnat_compilation_model id36}@anchor{84} +@subsection Introduction to Libraries in GNAT + + +A library is, conceptually, a collection of objects which does not have its +own main thread of execution, but rather provides certain services to the +applications that use it. A library can be either statically linked with the +application, in which case its code is directly included in the application, +or, on platforms that support it, be dynamically linked, in which case +its code is shared by all applications making use of this library. + +GNAT supports both types of libraries. +In the static case, the compiled code can be provided in different ways. The +simplest approach is to provide directly the set of objects resulting from +compilation of the library source files. Alternatively, you can group the +objects into an archive using whatever commands are provided by the operating +system. For the latter case, the objects are grouped into a shared library. + +In the GNAT environment, a library has three types of components: + + +@itemize * + +@item +Source files, + +@item +@code{ALI} files (see @ref{44,,The Ada Library Information Files}), and + +@item +Object files, an archive or a shared library. +@end itemize + +A GNAT library may expose all its source files, which is useful for +documentation purposes. Alternatively, it may expose only the units needed by +an external user to make use of the library. That is to say, the specs +reflecting the library services along with all the units needed to compile +those specs, which can include generic bodies or any body implementing an +inlined routine. In the case of @emph{stand-alone libraries} those exposed +units are called @emph{interface units} (@ref{85,,Stand-alone Ada Libraries}). + +All compilation units comprising an application, including those in a library, +need to be elaborated in an order partially defined by Ada's semantics. GNAT +computes the elaboration order from the @code{ALI} files and this is why they +constitute a mandatory part of GNAT libraries. +@emph{Stand-alone libraries} are the exception to this rule because a specific +library elaboration routine is produced independently of the application(s) +using the library. + +@node General Ada Libraries,Stand-alone Ada Libraries,Introduction to Libraries in GNAT,GNAT and Libraries +@anchor{gnat_ugn/the_gnat_compilation_model general-ada-libraries}@anchor{86}@anchor{gnat_ugn/the_gnat_compilation_model id37}@anchor{87} +@subsection General Ada Libraries + + +@menu +* Building a library:: +* Installing a library:: +* Using a library:: + +@end menu + +@node Building a library,Installing a library,,General Ada Libraries +@anchor{gnat_ugn/the_gnat_compilation_model building-a-library}@anchor{88}@anchor{gnat_ugn/the_gnat_compilation_model id38}@anchor{89} +@subsubsection Building a library + + +The easiest way to build a library is to use the Project Manager, +which supports a special type of project called a @emph{Library Project} +(see @ref{8a,,Library Projects}). + +A project is considered a library project, when two project-level attributes +are defined in it: @cite{Library_Name} and @cite{Library_Dir}. In order to +control different aspects of library configuration, additional optional +project-level attributes can be specified: + + +@itemize * + +@item + +@table @asis + +@item @emph{Library_Kind} + +This attribute controls whether the library is to be static or dynamic +@end table + +@item + +@table @asis + +@item @emph{Library_Version} + +This attribute specifies the library version; this value is used +during dynamic linking of shared libraries to determine if the currently +installed versions of the binaries are compatible. +@end table + +@item +@emph{Library_Options} + +@item + +@table @asis + +@item @emph{Library_GCC} + +These attributes specify additional low-level options to be used during +library generation, and redefine the actual application used to generate +library. +@end table +@end itemize + +The GNAT Project Manager takes full care of the library maintenance task, +including recompilation of the source files for which objects do not exist +or are not up to date, assembly of the library archive, and installation of +the library (i.e., copying associated source, object and @code{ALI} files +to the specified location). + +Here is a simple library project file: + +@example +project My_Lib is + for Source_Dirs use ("src1", "src2"); + for Object_Dir use "obj"; + for Library_Name use "mylib"; + for Library_Dir use "lib"; + for Library_Kind use "dynamic"; +end My_lib; +@end example + +and the compilation command to build and install the library: + +@example +$ gnatmake -Pmy_lib +@end example + +It is not entirely trivial to perform manually all the steps required to +produce a library. We recommend that you use the GNAT Project Manager +for this task. In special cases where this is not desired, the necessary +steps are discussed below. + +There are various possibilities for compiling the units that make up the +library: for example with a Makefile (@ref{21,,Using the GNU make Utility}) or +with a conventional script. For simple libraries, it is also possible to create +a dummy main program which depends upon all the packages that comprise the +interface of the library. This dummy main program can then be given to +@emph{gnatmake}, which will ensure that all necessary objects are built. + +After this task is accomplished, you should follow the standard procedure +of the underlying operating system to produce the static or shared library. + +Here is an example of such a dummy program: + +@example +with My_Lib.Service1; +with My_Lib.Service2; +with My_Lib.Service3; +procedure My_Lib_Dummy is +begin + null; +end; +@end example + +Here are the generic commands that will build an archive or a shared library. + +@example +# compiling the library +$ gnatmake -c my_lib_dummy.adb + +# we don't need the dummy object itself +$ rm my_lib_dummy.o my_lib_dummy.ali + +# create an archive with the remaining objects +$ ar rc libmy_lib.a *.o +# some systems may require "ranlib" to be run as well + +# or create a shared library +$ gcc -shared -o libmy_lib.so *.o +# some systems may require the code to have been compiled with -fPIC + +# remove the object files that are now in the library +$ rm *.o + +# Make the ALI files read-only so that gnatmake will not try to +# regenerate the objects that are in the library +$ chmod -w *.ali +@end example + +Please note that the library must have a name of the form @code{lib@emph{xxx}.a} +or @code{lib@emph{xxx}.so} (or @code{lib@emph{xxx}.dll} on Windows) in order to +be accessed by the directive @code{-l@emph{xxx}} at link time. + +@node Installing a library,Using a library,Building a library,General Ada Libraries +@anchor{gnat_ugn/the_gnat_compilation_model installing-a-library}@anchor{8b}@anchor{gnat_ugn/the_gnat_compilation_model id39}@anchor{8c} +@subsubsection Installing a library + + +@geindex ADA_PROJECT_PATH + +@geindex GPR_PROJECT_PATH + +If you use project files, library installation is part of the library build +process (@ref{8d,,Installing a library with project files}). + +When project files are not an option, it is also possible, but not recommended, +to install the library so that the sources needed to use the library are on the +Ada source path and the ALI files & libraries be on the Ada Object path (see +@ref{8e,,Search Paths and the Run-Time Library (RTL)}. Alternatively, the system +administrator can place general-purpose libraries in the default compiler +paths, by specifying the libraries' location in the configuration files +@code{ada_source_path} and @code{ada_object_path}. These configuration files +must be located in the GNAT installation tree at the same place as the gcc spec +file. The location of the gcc spec file can be determined as follows: + +@example +$ gcc -v +@end example + +The configuration files mentioned above have a simple format: each line +must contain one unique directory name. +Those names are added to the corresponding path +in their order of appearance in the file. The names can be either absolute +or relative; in the latter case, they are relative to where theses files +are located. + +The files @code{ada_source_path} and @code{ada_object_path} might not be +present in a +GNAT installation, in which case, GNAT will look for its run-time library in +the directories @code{adainclude} (for the sources) and @code{adalib} (for the +objects and @code{ALI} files). When the files exist, the compiler does not +look in @code{adainclude} and @code{adalib}, and thus the +@code{ada_source_path} file +must contain the location for the GNAT run-time sources (which can simply +be @code{adainclude}). In the same way, the @code{ada_object_path} file must +contain the location for the GNAT run-time objects (which can simply +be @code{adalib}). + +You can also specify a new default path to the run-time library at compilation +time with the switch @emph{--RTS=rts-path}. You can thus choose / change +the run-time library you want your program to be compiled with. This switch is +recognized by @emph{gcc}, @emph{gnatmake}, @emph{gnatbind}, +@emph{gnatls}, @emph{gnatfind} and @emph{gnatxref}. + +It is possible to install a library before or after the standard GNAT +library, by reordering the lines in the configuration files. In general, a +library must be installed before the GNAT library if it redefines +any part of it. + +@node Using a library,,Installing a library,General Ada Libraries +@anchor{gnat_ugn/the_gnat_compilation_model using-a-library}@anchor{8f}@anchor{gnat_ugn/the_gnat_compilation_model id40}@anchor{90} +@subsubsection Using a library + + +Once again, the project facility greatly simplifies the use of +libraries. In this context, using a library is just a matter of adding a +@emph{with} clause in the user project. For instance, to make use of the +library @cite{My_Lib} shown in examples in earlier sections, you can +write: + +@example +with "my_lib"; +project My_Proj is + ... +end My_Proj; +@end example + +Even if you have a third-party, non-Ada library, you can still use GNAT's +Project Manager facility to provide a wrapper for it. For example, the +following project, when @emph{with}ed by your main project, will link with the +third-party library @code{liba.a}: + +@example +project Liba is + for Externally_Built use "true"; + for Source_Files use (); + for Library_Dir use "lib"; + for Library_Name use "a"; + for Library_Kind use "static"; +end Liba; +@end example + +This is an alternative to the use of @cite{pragma Linker_Options}. It is +especially interesting in the context of systems with several interdependent +static libraries where finding a proper linker order is not easy and best be +left to the tools having visibility over project dependence information. + +In order to use an Ada library manually, you need to make sure that this +library is on both your source and object path +(see @ref{8e,,Search Paths and the Run-Time Library (RTL)} +and @ref{91,,Search Paths for gnatbind}). Furthermore, when the objects are grouped +in an archive or a shared library, you need to specify the desired +library at link time. + +For example, you can use the library @code{mylib} installed in +@code{/dir/my_lib_src} and @code{/dir/my_lib_obj} with the following commands: + +@example +$ gnatmake -aI/dir/my_lib_src -aO/dir/my_lib_obj my_appl \\ + -largs -lmy_lib +@end example + +This can be expressed more simply: + +@example +$ gnatmake my_appl +@end example + +when the following conditions are met: + + +@itemize * + +@item +@code{/dir/my_lib_src} has been added by the user to the environment +variable +@geindex ADA_INCLUDE_PATH +@geindex environment variable; ADA_INCLUDE_PATH +@code{ADA_INCLUDE_PATH}, or by the administrator to the file +@code{ada_source_path} + +@item +@code{/dir/my_lib_obj} has been added by the user to the environment +variable +@geindex ADA_OBJECTS_PATH +@geindex environment variable; ADA_OBJECTS_PATH +@code{ADA_OBJECTS_PATH}, or by the administrator to the file +@code{ada_object_path} + +@item +a pragma @cite{Linker_Options} has been added to one of the sources. +For example: + +@example +pragma Linker_Options ("-lmy_lib"); +@end example +@end itemize + +Note that you may also load a library dynamically at +run time given its filename, as illustrated in the GNAT @code{plugins} example +in the directory @code{share/examples/gnat/plugins} within the GNAT +install area. + +@node Stand-alone Ada Libraries,Rebuilding the GNAT Run-Time Library,General Ada Libraries,GNAT and Libraries +@anchor{gnat_ugn/the_gnat_compilation_model stand-alone-ada-libraries}@anchor{85}@anchor{gnat_ugn/the_gnat_compilation_model id41}@anchor{92} +@subsection Stand-alone Ada Libraries + + +@geindex Stand-alone libraries + +@menu +* Introduction to Stand-alone Libraries:: +* Building a Stand-alone Library:: +* Creating a Stand-alone Library to be used in a non-Ada context:: +* Restrictions in Stand-alone Libraries:: + +@end menu + +@node Introduction to Stand-alone Libraries,Building a Stand-alone Library,,Stand-alone Ada Libraries +@anchor{gnat_ugn/the_gnat_compilation_model introduction-to-stand-alone-libraries}@anchor{93}@anchor{gnat_ugn/the_gnat_compilation_model id42}@anchor{94} +@subsubsection Introduction to Stand-alone Libraries + + +A Stand-alone Library (abbreviated 'SAL') is a library that contains the +necessary code to +elaborate the Ada units that are included in the library. In contrast with +an ordinary library, which consists of all sources, objects and @code{ALI} +files of the +library, a SAL may specify a restricted subset of compilation units +to serve as a library interface. In this case, the fully +self-sufficient set of files will normally consist of an objects +archive, the sources of interface units' specs, and the @code{ALI} +files of interface units. +If an interface spec contains a generic unit or an inlined subprogram, +the body's +source must also be provided; if the units that must be provided in the source +form depend on other units, the source and @code{ALI} files of those must +also be provided. + +The main purpose of a SAL is to minimize the recompilation overhead of client +applications when a new version of the library is installed. Specifically, +if the interface sources have not changed, client applications do not need to +be recompiled. If, furthermore, a SAL is provided in the shared form and its +version, controlled by @cite{Library_Version} attribute, is not changed, +then the clients do not need to be relinked. + +SALs also allow the library providers to minimize the amount of library source +text exposed to the clients. Such 'information hiding' might be useful or +necessary for various reasons. + +Stand-alone libraries are also well suited to be used in an executable whose +main routine is not written in Ada. + +@node Building a Stand-alone Library,Creating a Stand-alone Library to be used in a non-Ada context,Introduction to Stand-alone Libraries,Stand-alone Ada Libraries +@anchor{gnat_ugn/the_gnat_compilation_model id43}@anchor{95}@anchor{gnat_ugn/the_gnat_compilation_model building-a-stand-alone-library}@anchor{96} +@subsubsection Building a Stand-alone Library + + +GNAT's Project facility provides a simple way of building and installing +stand-alone libraries; see @ref{97,,Stand-alone Library Projects}. +To be a Stand-alone Library Project, in addition to the two attributes +that make a project a Library Project (@cite{Library_Name} and +@cite{Library_Dir}; see @ref{8a,,Library Projects}), the attribute +@cite{Library_Interface} must be defined. For example: + +@example +for Library_Dir use "lib_dir"; +for Library_Name use "dummy"; +for Library_Interface use ("int1", "int1.child"); +@end example + +Attribute @cite{Library_Interface} has a non-empty string list value, +each string in the list designating a unit contained in an immediate source +of the project file. + +When a Stand-alone Library is built, first the binder is invoked to build +a package whose name depends on the library name +(@code{b~dummy.ads/b} in the example above). +This binder-generated package includes initialization and +finalization procedures whose +names depend on the library name (@cite{dummyinit} and @cite{dummyfinal} +in the example +above). The object corresponding to this package is included in the library. + +You must ensure timely (e.g., prior to any use of interfaces in the SAL) +calling of these procedures if a static SAL is built, or if a shared SAL +is built +with the project-level attribute @cite{Library_Auto_Init} set to +@cite{"false"}. + +For a Stand-Alone Library, only the @code{ALI} files of the Interface Units +(those that are listed in attribute @cite{Library_Interface}) are copied to +the Library Directory. As a consequence, only the Interface Units may be +imported from Ada units outside of the library. If other units are imported, +the binding phase will fail. + +It is also possible to build an encapsulated library where not only +the code to elaborate and finalize the library is embedded but also +ensuring that the library is linked only against static +libraries. So an encapsulated library only depends on system +libraries, all other code, including the GNAT runtime, is embedded. To +build an encapsulated library the attribute +@cite{Library_Standalone} must be set to @cite{encapsulated}: + +@example +for Library_Dir use "lib_dir"; +for Library_Name use "dummy"; +for Library_Kind use "dynamic"; +for Library_Interface use ("int1", "int1.child"); +for Library_Standalone use "encapsulated"; +@end example + +The default value for this attribute is @cite{standard} in which case +a stand-alone library is built. + +The attribute @cite{Library_Src_Dir} may be specified for a +Stand-Alone Library. @cite{Library_Src_Dir} is a simple attribute that has a +single string value. Its value must be the path (absolute or relative to the +project directory) of an existing directory. This directory cannot be the +object directory or one of the source directories, but it can be the same as +the library directory. The sources of the Interface +Units of the library that are needed by an Ada client of the library will be +copied to the designated directory, called the Interface Copy directory. +These sources include the specs of the Interface Units, but they may also +include bodies and subunits, when pragmas @cite{Inline} or @cite{Inline_Always} +are used, or when there is a generic unit in the spec. Before the sources +are copied to the Interface Copy directory, an attempt is made to delete all +files in the Interface Copy directory. + +Building stand-alone libraries by hand is somewhat tedious, but for those +occasions when it is necessary here are the steps that you need to perform: + + +@itemize * + +@item +Compile all library sources. + +@item +Invoke the binder with the switch @emph{-n} (No Ada main program), +with all the @code{ALI} files of the interfaces, and +with the switch @emph{-L} to give specific names to the @cite{init} +and @cite{final} procedures. For example: + +@example +$ gnatbind -n int1.ali int2.ali -Lsal1 +@end example + +@item +Compile the binder generated file: + +@example +$ gcc -c b~int2.adb +@end example + +@item +Link the dynamic library with all the necessary object files, +indicating to the linker the names of the @cite{init} (and possibly +@cite{final}) procedures for automatic initialization (and finalization). +The built library should be placed in a directory different from +the object directory. + +@item +Copy the @cite{ALI} files of the interface to the library directory, +add in this copy an indication that it is an interface to a SAL +(i.e., add a word @emph{SL} on the line in the @code{ALI} file that starts +with letter 'P') and make the modified copy of the @code{ALI} file +read-only. +@end itemize + +Using SALs is not different from using other libraries +(see @ref{8f,,Using a library}). + +@node Creating a Stand-alone Library to be used in a non-Ada context,Restrictions in Stand-alone Libraries,Building a Stand-alone Library,Stand-alone Ada Libraries +@anchor{gnat_ugn/the_gnat_compilation_model creating-a-stand-alone-library-to-be-used-in-a-non-ada-context}@anchor{98}@anchor{gnat_ugn/the_gnat_compilation_model id44}@anchor{99} +@subsubsection Creating a Stand-alone Library to be used in a non-Ada context + + +It is easy to adapt the SAL build procedure discussed above for use of a SAL in +a non-Ada context. + +The only extra step required is to ensure that library interface subprograms +are compatible with the main program, by means of @cite{pragma Export} +or @cite{pragma Convention}. + +Here is an example of simple library interface for use with C main program: + +@example +package My_Package is + + procedure Do_Something; + pragma Export (C, Do_Something, "do_something"); + + procedure Do_Something_Else; + pragma Export (C, Do_Something_Else, "do_something_else"); + +end My_Package; +@end example + +On the foreign language side, you must provide a 'foreign' view of the +library interface; remember that it should contain elaboration routines in +addition to interface subprograms. + +The example below shows the content of @cite{mylib_interface.h} (note +that there is no rule for the naming of this file, any name can be used) + +@example +/* the library elaboration procedure */ +extern void mylibinit (void); + +/* the library finalization procedure */ +extern void mylibfinal (void); + +/* the interface exported by the library */ +extern void do_something (void); +extern void do_something_else (void); +@end example + +Libraries built as explained above can be used from any program, provided +that the elaboration procedures (named @cite{mylibinit} in the previous +example) are called before the library services are used. Any number of +libraries can be used simultaneously, as long as the elaboration +procedure of each library is called. + +Below is an example of a C program that uses the @cite{mylib} library. + +@example +#include "mylib_interface.h" + +int +main (void) +@{ + /* First, elaborate the library before using it */ + mylibinit (); + + /* Main program, using the library exported entities */ + do_something (); + do_something_else (); + + /* Library finalization at the end of the program */ + mylibfinal (); + return 0; +@} +@end example + +Note that invoking any library finalization procedure generated by +@cite{gnatbind} shuts down the Ada run-time environment. +Consequently, the +finalization of all Ada libraries must be performed at the end of the program. +No call to these libraries or to the Ada run-time library should be made +after the finalization phase. + +Note also that special care must be taken with multi-tasks +applications. The initialization and finalization routines are not +protected against concurrent access. If such requirement is needed it +must be ensured at the application level using a specific operating +system services like a mutex or a critical-section. + +@node Restrictions in Stand-alone Libraries,,Creating a Stand-alone Library to be used in a non-Ada context,Stand-alone Ada Libraries +@anchor{gnat_ugn/the_gnat_compilation_model id45}@anchor{9a}@anchor{gnat_ugn/the_gnat_compilation_model restrictions-in-stand-alone-libraries}@anchor{9b} +@subsubsection Restrictions in Stand-alone Libraries + + +The pragmas listed below should be used with caution inside libraries, +as they can create incompatibilities with other Ada libraries: + + +@itemize * + +@item +pragma @cite{Locking_Policy} + +@item +pragma @cite{Partition_Elaboration_Policy} + +@item +pragma @cite{Queuing_Policy} + +@item +pragma @cite{Task_Dispatching_Policy} + +@item +pragma @cite{Unreserve_All_Interrupts} +@end itemize + +When using a library that contains such pragmas, the user must make sure +that all libraries use the same pragmas with the same values. Otherwise, +@cite{Program_Error} will +be raised during the elaboration of the conflicting +libraries. The usage of these pragmas and its consequences for the user +should therefore be well documented. + +Similarly, the traceback in the exception occurrence mechanism should be +enabled or disabled in a consistent manner across all libraries. +Otherwise, Program_Error will be raised during the elaboration of the +conflicting libraries. + +If the @cite{Version} or @cite{Body_Version} +attributes are used inside a library, then you need to +perform a @cite{gnatbind} step that specifies all @code{ALI} files in all +libraries, so that version identifiers can be properly computed. +In practice these attributes are rarely used, so this is unlikely +to be a consideration. + +@node Rebuilding the GNAT Run-Time Library,,Stand-alone Ada Libraries,GNAT and Libraries +@anchor{gnat_ugn/the_gnat_compilation_model id46}@anchor{9c}@anchor{gnat_ugn/the_gnat_compilation_model rebuilding-the-gnat-run-time-library}@anchor{9d} +@subsection Rebuilding the GNAT Run-Time Library + + +@geindex GNAT Run-Time Library +@geindex rebuilding + +@geindex Building the GNAT Run-Time Library + +@geindex Rebuilding the GNAT Run-Time Library + +@geindex Run-Time Library +@geindex rebuilding + +It may be useful to recompile the GNAT library in various contexts, the +most important one being the use of partition-wide configuration pragmas +such as @cite{Normalize_Scalars}. A special Makefile called +@cite{Makefile.adalib} is provided to that effect and can be found in +the directory containing the GNAT library. The location of this +directory depends on the way the GNAT environment has been installed and can +be determined by means of the command: + +@example +$ gnatls -v +@end example + +The last entry in the object search path usually contains the +gnat library. This Makefile contains its own documentation and in +particular the set of instructions needed to rebuild a new library and +to use it. + +@geindex Conditional compilation + +@node Conditional Compilation,Mixed Language Programming,GNAT and Libraries,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model id47}@anchor{9e}@anchor{gnat_ugn/the_gnat_compilation_model conditional-compilation}@anchor{18} +@section Conditional Compilation + + +This section presents some guidelines for modeling conditional compilation in Ada and describes the +gnatprep preprocessor utility. + +@geindex Conditional compilation + +@menu +* Modeling Conditional Compilation in Ada:: +* Preprocessing with gnatprep:: +* Integrated Preprocessing:: + +@end menu + +@node Modeling Conditional Compilation in Ada,Preprocessing with gnatprep,,Conditional Compilation +@anchor{gnat_ugn/the_gnat_compilation_model modeling-conditional-compilation-in-ada}@anchor{9f}@anchor{gnat_ugn/the_gnat_compilation_model id48}@anchor{a0} +@subsection Modeling Conditional Compilation in Ada + + +It is often necessary to arrange for a single source program +to serve multiple purposes, where it is compiled in different +ways to achieve these different goals. Some examples of the +need for this feature are + + +@itemize * + +@item +Adapting a program to a different hardware environment + +@item +Adapting a program to a different target architecture + +@item +Turning debugging features on and off + +@item +Arranging for a program to compile with different compilers +@end itemize + +In C, or C++, the typical approach would be to use the preprocessor +that is defined as part of the language. The Ada language does not +contain such a feature. This is not an oversight, but rather a very +deliberate design decision, based on the experience that overuse of +the preprocessing features in C and C++ can result in programs that +are extremely difficult to maintain. For example, if we have ten +switches that can be on or off, this means that there are a thousand +separate programs, any one of which might not even be syntactically +correct, and even if syntactically correct, the resulting program +might not work correctly. Testing all combinations can quickly become +impossible. + +Nevertheless, the need to tailor programs certainly exists, and in +this section we will discuss how this can +be achieved using Ada in general, and GNAT in particular. + +@menu +* Use of Boolean Constants:: +* Debugging - A Special Case:: +* Conditionalizing Declarations:: +* Use of Alternative Implementations:: +* Preprocessing:: + +@end menu + +@node Use of Boolean Constants,Debugging - A Special Case,,Modeling Conditional Compilation in Ada +@anchor{gnat_ugn/the_gnat_compilation_model id49}@anchor{a1}@anchor{gnat_ugn/the_gnat_compilation_model use-of-boolean-constants}@anchor{a2} +@subsubsection Use of Boolean Constants + + +In the case where the difference is simply which code +sequence is executed, the cleanest solution is to use Boolean +constants to control which code is executed. + +@example +FP_Initialize_Required : constant Boolean := True; +... +if FP_Initialize_Required then +... +end if; +@end example + +Not only will the code inside the @cite{if} statement not be executed if +the constant Boolean is @cite{False}, but it will also be completely +deleted from the program. +However, the code is only deleted after the @cite{if} statement +has been checked for syntactic and semantic correctness. +(In contrast, with preprocessors the code is deleted before the +compiler ever gets to see it, so it is not checked until the switch +is turned on.) + +@geindex Preprocessors (contrasted with conditional compilation) + +Typically the Boolean constants will be in a separate package, +something like: + +@example +package Config is + FP_Initialize_Required : constant Boolean := True; + Reset_Available : constant Boolean := False; + ... +end Config; +@end example + +The @cite{Config} package exists in multiple forms for the various targets, +with an appropriate script selecting the version of @cite{Config} needed. +Then any other unit requiring conditional compilation can do a @emph{with} +of @cite{Config} to make the constants visible. + +@node Debugging - A Special Case,Conditionalizing Declarations,Use of Boolean Constants,Modeling Conditional Compilation in Ada +@anchor{gnat_ugn/the_gnat_compilation_model debugging-a-special-case}@anchor{a3}@anchor{gnat_ugn/the_gnat_compilation_model id50}@anchor{a4} +@subsubsection Debugging - A Special Case + + +A common use of conditional code is to execute statements (for example +dynamic checks, or output of intermediate results) under control of a +debug switch, so that the debugging behavior can be turned on and off. +This can be done using a Boolean constant to control whether the code +is active: + +@example +if Debugging then + Put_Line ("got to the first stage!"); +end if; +@end example + +or + +@example +if Debugging and then Temperature > 999.0 then + raise Temperature_Crazy; +end if; +@end example + +@geindex pragma Assert + +Since this is a common case, there are special features to deal with +this in a convenient manner. For the case of tests, Ada 2005 has added +a pragma @cite{Assert} that can be used for such tests. This pragma is modeled +on the @cite{Assert} pragma that has always been available in GNAT, so this +feature may be used with GNAT even if you are not using Ada 2005 features. +The use of pragma @cite{Assert} is described in the +@cite{GNAT_Reference_Manual}, but as an +example, the last test could be written: + +@example +pragma Assert (Temperature <= 999.0, "Temperature Crazy"); +@end example + +or simply + +@example +pragma Assert (Temperature <= 999.0); +@end example + +In both cases, if assertions are active and the temperature is excessive, +the exception @cite{Assert_Failure} will be raised, with the given string in +the first case or a string indicating the location of the pragma in the second +case used as the exception message. + +@geindex pragma Assertion_Policy + +You can turn assertions on and off by using the @cite{Assertion_Policy} +pragma. + +@geindex -gnata switch + +This is an Ada 2005 pragma which is implemented in all modes by +GNAT. Alternatively, you can use the @emph{-gnata} switch +to enable assertions from the command line, which applies to +all versions of Ada. + +@geindex pragma Debug + +For the example above with the @cite{Put_Line}, the GNAT-specific pragma +@cite{Debug} can be used: + +@example +pragma Debug (Put_Line ("got to the first stage!")); +@end example + +If debug pragmas are enabled, the argument, which must be of the form of +a procedure call, is executed (in this case, @cite{Put_Line} will be called). +Only one call can be present, but of course a special debugging procedure +containing any code you like can be included in the program and then +called in a pragma @cite{Debug} argument as needed. + +One advantage of pragma @cite{Debug} over the @cite{if Debugging then} +construct is that pragma @cite{Debug} can appear in declarative contexts, +such as at the very beginning of a procedure, before local declarations have +been elaborated. + +@geindex pragma Debug_Policy + +Debug pragmas are enabled using either the @emph{-gnata} switch that also +controls assertions, or with a separate Debug_Policy pragma. + +The latter pragma is new in the Ada 2005 versions of GNAT (but it can be used +in Ada 95 and Ada 83 programs as well), and is analogous to +pragma @cite{Assertion_Policy} to control assertions. + +@cite{Assertion_Policy} and @cite{Debug_Policy} are configuration pragmas, +and thus they can appear in @code{gnat.adc} if you are not using a +project file, or in the file designated to contain configuration pragmas +in a project file. +They then apply to all subsequent compilations. In practice the use of +the @emph{-gnata} switch is often the most convenient method of controlling +the status of these pragmas. + +Note that a pragma is not a statement, so in contexts where a statement +sequence is required, you can't just write a pragma on its own. You have +to add a @cite{null} statement. + +@example +if ... then + ... -- some statements +else + pragma Assert (Num_Cases < 10); + null; +end if; +@end example + +@node Conditionalizing Declarations,Use of Alternative Implementations,Debugging - A Special Case,Modeling Conditional Compilation in Ada +@anchor{gnat_ugn/the_gnat_compilation_model conditionalizing-declarations}@anchor{a5}@anchor{gnat_ugn/the_gnat_compilation_model id51}@anchor{a6} +@subsubsection Conditionalizing Declarations + + +In some cases it may be necessary to conditionalize declarations to meet +different requirements. For example we might want a bit string whose length +is set to meet some hardware message requirement. + +This may be possible using declare blocks controlled +by conditional constants: + +@example +if Small_Machine then + declare + X : Bit_String (1 .. 10); + begin + ... + end; +else + declare + X : Large_Bit_String (1 .. 1000); + begin + ... + end; +end if; +@end example + +Note that in this approach, both declarations are analyzed by the +compiler so this can only be used where both declarations are legal, +even though one of them will not be used. + +Another approach is to define integer constants, e.g., @cite{Bits_Per_Word}, +or Boolean constants, e.g., @cite{Little_Endian}, and then write declarations +that are parameterized by these constants. For example + +@example +for Rec use + Field1 at 0 range Boolean'Pos (Little_Endian) * 10 .. Bits_Per_Word; +end record; +@end example + +If @cite{Bits_Per_Word} is set to 32, this generates either + +@example +for Rec use + Field1 at 0 range 0 .. 32; +end record; +@end example + +for the big endian case, or + +@example +for Rec use record + Field1 at 0 range 10 .. 32; +end record; +@end example + +for the little endian case. Since a powerful subset of Ada expression +notation is usable for creating static constants, clever use of this +feature can often solve quite difficult problems in conditionalizing +compilation (note incidentally that in Ada 95, the little endian +constant was introduced as @cite{System.Default_Bit_Order}, so you do not +need to define this one yourself). + +@node Use of Alternative Implementations,Preprocessing,Conditionalizing Declarations,Modeling Conditional Compilation in Ada +@anchor{gnat_ugn/the_gnat_compilation_model use-of-alternative-implementations}@anchor{a7}@anchor{gnat_ugn/the_gnat_compilation_model id52}@anchor{a8} +@subsubsection Use of Alternative Implementations + + +In some cases, none of the approaches described above are adequate. This +can occur for example if the set of declarations required is radically +different for two different configurations. + +In this situation, the official Ada way of dealing with conditionalizing +such code is to write separate units for the different cases. As long as +this does not result in excessive duplication of code, this can be done +without creating maintenance problems. The approach is to share common +code as far as possible, and then isolate the code and declarations +that are different. Subunits are often a convenient method for breaking +out a piece of a unit that is to be conditionalized, with separate files +for different versions of the subunit for different targets, where the +build script selects the right one to give to the compiler. + +@geindex Subunits (and conditional compilation) + +As an example, consider a situation where a new feature in Ada 2005 +allows something to be done in a really nice way. But your code must be able +to compile with an Ada 95 compiler. Conceptually you want to say: + +@example +if Ada_2005 then + ... neat Ada 2005 code +else + ... not quite as neat Ada 95 code +end if; +@end example + +where @cite{Ada_2005} is a Boolean constant. + +But this won't work when @cite{Ada_2005} is set to @cite{False}, +since the @cite{then} clause will be illegal for an Ada 95 compiler. +(Recall that although such unreachable code would eventually be deleted +by the compiler, it still needs to be legal. If it uses features +introduced in Ada 2005, it will be illegal in Ada 95.) + +So instead we write + +@example +procedure Insert is separate; +@end example + +Then we have two files for the subunit @cite{Insert}, with the two sets of +code. +If the package containing this is called @cite{File_Queries}, then we might +have two files + + +@itemize * + +@item +@code{file_queries-insert-2005.adb} + +@item +@code{file_queries-insert-95.adb} +@end itemize + +and the build script renames the appropriate file to @code{file_queries-insert.adb} and then carries out the compilation. + +This can also be done with project files' naming schemes. For example: + +@example +for body ("File_Queries.Insert") use "file_queries-insert-2005.ada"; +@end example + +Note also that with project files it is desirable to use a different extension +than @code{ads} / @code{adb} for alternative versions. Otherwise a naming +conflict may arise through another commonly used feature: to declare as part +of the project a set of directories containing all the sources obeying the +default naming scheme. + +The use of alternative units is certainly feasible in all situations, +and for example the Ada part of the GNAT run-time is conditionalized +based on the target architecture using this approach. As a specific example, +consider the implementation of the AST feature in VMS. There is one +spec: @code{s-asthan.ads} which is the same for all architectures, and three +bodies: + + +@itemize * + +@item + +@table @asis + +@item @code{s-asthan.adb} + +used for all non-VMS operating systems +@end table + +@item + +@table @asis + +@item @code{s-asthan-vms-alpha.adb} + +used for VMS on the Alpha +@end table + +@item + +@table @asis + +@item @code{s-asthan-vms-ia64.adb} + +used for VMS on the ia64 +@end table +@end itemize + +The dummy version @code{s-asthan.adb} simply raises exceptions noting that +this operating system feature is not available, and the two remaining +versions interface with the corresponding versions of VMS to provide +VMS-compatible AST handling. The GNAT build script knows the architecture +and operating system, and automatically selects the right version, +renaming it if necessary to @code{s-asthan.adb} before the run-time build. + +Another style for arranging alternative implementations is through Ada's +access-to-subprogram facility. +In case some functionality is to be conditionally included, +you can declare an access-to-procedure variable @cite{Ref} that is initialized +to designate a 'do nothing' procedure, and then invoke @cite{Ref.all} +when appropriate. +In some library package, set @cite{Ref} to @cite{Proc'Access} for some +procedure @cite{Proc} that performs the relevant processing. +The initialization only occurs if the library package is included in the +program. +The same idea can also be implemented using tagged types and dispatching +calls. + +@node Preprocessing,,Use of Alternative Implementations,Modeling Conditional Compilation in Ada +@anchor{gnat_ugn/the_gnat_compilation_model preprocessing}@anchor{a9}@anchor{gnat_ugn/the_gnat_compilation_model id53}@anchor{aa} +@subsubsection Preprocessing + + +@geindex Preprocessing + +Although it is quite possible to conditionalize code without the use of +C-style preprocessing, as described earlier in this section, it is +nevertheless convenient in some cases to use the C approach. Moreover, +older Ada compilers have often provided some preprocessing capability, +so legacy code may depend on this approach, even though it is not +standard. + +To accommodate such use, GNAT provides a preprocessor (modeled to a large +extent on the various preprocessors that have been used +with legacy code on other compilers, to enable easier transition). + +@geindex gnatprep + +The preprocessor may be used in two separate modes. It can be used quite +separately from the compiler, to generate a separate output source file +that is then fed to the compiler as a separate step. This is the +@cite{gnatprep} utility, whose use is fully described in +@ref{19,,Preprocessing with gnatprep}. + +The preprocessing language allows such constructs as + +@example +#if DEBUG or else (PRIORITY > 4) then + bunch of declarations +#else + completely different bunch of declarations +#end if; +@end example + +The values of the symbols @cite{DEBUG} and @cite{PRIORITY} can be +defined either on the command line or in a separate file. + +The other way of running the preprocessor is even closer to the C style and +often more convenient. In this approach the preprocessing is integrated into +the compilation process. The compiler is fed the preprocessor input which +includes @cite{#if} lines etc, and then the compiler carries out the +preprocessing internally and processes the resulting output. +For more details on this approach, see @ref{1a,,Integrated Preprocessing}. + +@node Preprocessing with gnatprep,Integrated Preprocessing,Modeling Conditional Compilation in Ada,Conditional Compilation +@anchor{gnat_ugn/the_gnat_compilation_model id54}@anchor{ab}@anchor{gnat_ugn/the_gnat_compilation_model preprocessing-with-gnatprep}@anchor{19} +@subsection Preprocessing with @cite{gnatprep} + + +@geindex gnatprep + +@geindex Preprocessing (gnatprep) + +This section discusses how to use GNAT's @cite{gnatprep} utility for simple +preprocessing. +Although designed for use with GNAT, @cite{gnatprep} does not depend on any +special GNAT features. +For further discussion of conditional compilation in general, see +@ref{18,,Conditional Compilation}. + +@menu +* Preprocessing Symbols:: +* Using gnatprep:: +* Switches for gnatprep:: +* Form of Definitions File:: +* Form of Input Text for gnatprep:: + +@end menu + +@node Preprocessing Symbols,Using gnatprep,,Preprocessing with gnatprep +@anchor{gnat_ugn/the_gnat_compilation_model id55}@anchor{ac}@anchor{gnat_ugn/the_gnat_compilation_model preprocessing-symbols}@anchor{ad} +@subsubsection Preprocessing Symbols + + +Preprocessing symbols are defined in definition files and referred to in +sources to be preprocessed. A Preprocessing symbol is an identifier, following +normal Ada (case-insensitive) rules for its syntax, with the restriction that +all characters need to be in the ASCII set (no accented letters). + +@node Using gnatprep,Switches for gnatprep,Preprocessing Symbols,Preprocessing with gnatprep +@anchor{gnat_ugn/the_gnat_compilation_model using-gnatprep}@anchor{ae}@anchor{gnat_ugn/the_gnat_compilation_model id56}@anchor{af} +@subsubsection Using @cite{gnatprep} + + +To call @cite{gnatprep} use: + +@example +$ gnatprep [`switches`] `infile` `outfile` [`deffile`] +@end example + +where + + +@itemize * + +@item + +@table @asis + +@item @emph{switches} + +is an optional sequence of switches as described in the next section. +@end table + +@item + +@table @asis + +@item @emph{infile} + +is the full name of the input file, which is an Ada source +file containing preprocessor directives. +@end table + +@item + +@table @asis + +@item @emph{outfile} + +is the full name of the output file, which is an Ada source +in standard Ada form. When used with GNAT, this file name will +normally have an ads or adb suffix. +@end table + +@item + +@table @asis + +@item @emph{deffile} + +is the full name of a text file containing definitions of +preprocessing symbols to be referenced by the preprocessor. This argument is +optional, and can be replaced by the use of the @emph{-D} switch. +@end table +@end itemize + +@node Switches for gnatprep,Form of Definitions File,Using gnatprep,Preprocessing with gnatprep +@anchor{gnat_ugn/the_gnat_compilation_model switches-for-gnatprep}@anchor{b0}@anchor{gnat_ugn/the_gnat_compilation_model id57}@anchor{b1} +@subsubsection Switches for @cite{gnatprep} + + +@geindex -b (gnatprep) + + +@table @asis + +@item @code{-b} + +Causes both preprocessor lines and the lines deleted by +preprocessing to be replaced by blank lines in the output source file, +preserving line numbers in the output file. +@end table + +@geindex -c (gnatprep) + + +@table @asis + +@item @code{-c} + +Causes both preprocessor lines and the lines deleted +by preprocessing to be retained in the output source as comments marked +with the special string @cite{"--! "}. This option will result in line numbers +being preserved in the output file. +@end table + +@geindex -C (gnatprep) + + +@table @asis + +@item @code{-C} + +Causes comments to be scanned. Normally comments are ignored by gnatprep. +If this option is specified, then comments are scanned and any $symbol +substitutions performed as in program text. This is particularly useful +when structured comments are used (e.g., when writing programs in the +SPARK dialect of Ada). Note that this switch is not available when +doing integrated preprocessing (it would be useless in this context +since comments are ignored by the compiler in any case). +@end table + +@geindex -D (gnatprep) + + +@table @asis + +@item @code{-D@emph{symbol}=@emph{value}} + +Defines a new preprocessing symbol, associated with value. If no value is given +on the command line, then symbol is considered to be @cite{True}. This switch +can be used in place of a definition file. +@end table + +@geindex -r (gnatprep) + + +@table @asis + +@item @code{-r} + +Causes a @cite{Source_Reference} pragma to be generated that +references the original input file, so that error messages will use +the file name of this original file. The use of this switch implies +that preprocessor lines are not to be removed from the file, so its +use will force @emph{-b} mode if @emph{-c} +has not been specified explicitly. + +Note that if the file to be preprocessed contains multiple units, then +it will be necessary to @cite{gnatchop} the output file from +@cite{gnatprep}. If a @cite{Source_Reference} pragma is present +in the preprocessed file, it will be respected by +@cite{gnatchop -r} +so that the final chopped files will correctly refer to the original +input source file for @cite{gnatprep}. +@end table + +@geindex -s (gnatprep) + + +@table @asis + +@item @code{-s} + +Causes a sorted list of symbol names and values to be +listed on the standard output file. +@end table + +@geindex -u (gnatprep) + + +@table @asis + +@item @code{-u} + +Causes undefined symbols to be treated as having the value FALSE in the context +of a preprocessor test. In the absence of this option, an undefined symbol in +a @cite{#if} or @cite{#elsif} test will be treated as an error. +@end table + +Note: if neither @emph{-b} nor @emph{-c} is present, +then preprocessor lines and +deleted lines are completely removed from the output, unless -r is +specified, in which case -b is assumed. + +@node Form of Definitions File,Form of Input Text for gnatprep,Switches for gnatprep,Preprocessing with gnatprep +@anchor{gnat_ugn/the_gnat_compilation_model form-of-definitions-file}@anchor{b2}@anchor{gnat_ugn/the_gnat_compilation_model id58}@anchor{b3} +@subsubsection Form of Definitions File + + +The definitions file contains lines of the form: + +@example +symbol := value +@end example + +where @cite{symbol} is a preprocessing symbol, and @cite{value} is one of the following: + + +@itemize * + +@item +Empty, corresponding to a null substitution, + +@item +A string literal using normal Ada syntax, or + +@item +Any sequence of characters from the set @{letters, digits, period, underline@}. +@end itemize + +Comment lines may also appear in the definitions file, starting with +the usual @code{--}, +and comments may be added to the definitions lines. + +@node Form of Input Text for gnatprep,,Form of Definitions File,Preprocessing with gnatprep +@anchor{gnat_ugn/the_gnat_compilation_model id59}@anchor{b4}@anchor{gnat_ugn/the_gnat_compilation_model form-of-input-text-for-gnatprep}@anchor{b5} +@subsubsection Form of Input Text for @cite{gnatprep} + + +The input text may contain preprocessor conditional inclusion lines, +as well as general symbol substitution sequences. + +The preprocessor conditional inclusion commands have the form: + +@example +#if <expression> [then] + lines +#elsif <expression> [then] + lines +#elsif <expression> [then] + lines +... +#else + lines +#end if; +@end example + +In this example, <expression> is defined by the following grammar: + +@example +<expression> ::= <symbol> +<expression> ::= <symbol> = "<value>" +<expression> ::= <symbol> = <symbol> +<expression> ::= <symbol> = <integer> +<expression> ::= <symbol> > <integer> +<expression> ::= <symbol> >= <integer> +<expression> ::= <symbol> < <integer> +<expression> ::= <symbol> <= <integer> +<expression> ::= <symbol> 'Defined +<expression> ::= not <expression> +<expression> ::= <expression> and <expression> +<expression> ::= <expression> or <expression> +<expression> ::= <expression> and then <expression> +<expression> ::= <expression> or else <expression> +<expression> ::= ( <expression> ) +@end example + +Note the following restriction: it is not allowed to have "and" or "or" +following "not" in the same expression without parentheses. For example, this +is not allowed: + +@example +not X or Y +@end example + +This can be expressed instead as one of the following forms: + +@example +(not X) or Y +not (X or Y) +@end example + +For the first test (<expression> ::= <symbol>) the symbol must have +either the value true or false, that is to say the right-hand of the +symbol definition must be one of the (case-insensitive) literals +@cite{True} or @cite{False}. If the value is true, then the +corresponding lines are included, and if the value is false, they are +excluded. + +When comparing a symbol to an integer, the integer is any non negative +literal integer as defined in the Ada Reference Manual, such as 3, 16#FF# or +2#11#. The symbol value must also be a non negative integer. Integer values +in the range 0 .. 2**31-1 are supported. + +The test (<expression> ::= <symbol>'Defined) is true only if +the symbol has been defined in the definition file or by a @emph{-D} +switch on the command line. Otherwise, the test is false. + +The equality tests are case insensitive, as are all the preprocessor lines. + +If the symbol referenced is not defined in the symbol definitions file, +then the effect depends on whether or not switch @emph{-u} +is specified. If so, then the symbol is treated as if it had the value +false and the test fails. If this switch is not specified, then +it is an error to reference an undefined symbol. It is also an error to +reference a symbol that is defined with a value other than @cite{True} +or @cite{False}. + +The use of the @cite{not} operator inverts the sense of this logical test. +The @cite{not} operator cannot be combined with the @cite{or} or @cite{and} +operators, without parentheses. For example, "if not X or Y then" is not +allowed, but "if (not X) or Y then" and "if not (X or Y) then" are. + +The @cite{then} keyword is optional as shown + +The @cite{#} must be the first non-blank character on a line, but +otherwise the format is free form. Spaces or tabs may appear between +the @cite{#} and the keyword. The keywords and the symbols are case +insensitive as in normal Ada code. Comments may be used on a +preprocessor line, but other than that, no other tokens may appear on a +preprocessor line. Any number of @cite{elsif} clauses can be present, +including none at all. The @cite{else} is optional, as in Ada. + +The @cite{#} marking the start of a preprocessor line must be the first +non-blank character on the line, i.e., it must be preceded only by +spaces or horizontal tabs. + +Symbol substitution outside of preprocessor lines is obtained by using +the sequence: + +@example +$symbol +@end example + +anywhere within a source line, except in a comment or within a +string literal. The identifier +following the @cite{$} must match one of the symbols defined in the symbol +definition file, and the result is to substitute the value of the +symbol in place of @cite{$symbol} in the output file. + +Note that although the substitution of strings within a string literal +is not possible, it is possible to have a symbol whose defined value is +a string literal. So instead of setting XYZ to @cite{hello} and writing: + +@example +Header : String := "$XYZ"; +@end example + +you should set XYZ to @cite{"hello"} and write: + +@example +Header : String := $XYZ; +@end example + +and then the substitution will occur as desired. + +@node Integrated Preprocessing,,Preprocessing with gnatprep,Conditional Compilation +@anchor{gnat_ugn/the_gnat_compilation_model id60}@anchor{b6}@anchor{gnat_ugn/the_gnat_compilation_model integrated-preprocessing}@anchor{1a} +@subsection Integrated Preprocessing + + +GNAT sources may be preprocessed immediately before compilation. +In this case, the actual +text of the source is not the text of the source file, but is derived from it +through a process called preprocessing. Integrated preprocessing is specified +through switches @emph{-gnatep} and/or @emph{-gnateD}. @emph{-gnatep} +indicates, through a text file, the preprocessing data to be used. +@code{-gnateD} specifies or modifies the values of preprocessing symbol. +Note that integrated preprocessing applies only to Ada source files, it is +not available for configuration pragma files. + +Note that when integrated preprocessing is used, the output from the +preprocessor is not written to any external file. Instead it is passed +internally to the compiler. If you need to preserve the result of +preprocessing in a file, then you should use @emph{gnatprep} +to perform the desired preprocessing in stand-alone mode. + +It is recommended that @emph{gnatmake} switch -s should be +used when Integrated Preprocessing is used. The reason is that preprocessing +with another Preprocessing Data file without changing the sources will +not trigger recompilation without this switch. + +Note that @emph{gnatmake} switch -m will almost +always trigger recompilation for sources that are preprocessed, +because @emph{gnatmake} cannot compute the checksum of the source after +preprocessing. + +The actual preprocessing function is described in detail in section +@ref{19,,Preprocessing with gnatprep}. This section only describes how integrated +preprocessing is triggered and parameterized. + +@geindex -gnatep (gcc) + + +@table @asis + +@item @code{-gnatep=@emph{file}} + +This switch indicates to the compiler the file name (without directory +information) of the preprocessor data file to use. The preprocessor data file +should be found in the source directories. Note that when the compiler is +called by a builder such as (@emph{gnatmake} with a project +file, if the object directory is not also a source directory, the builder needs +to be called with @emph{-x}. + +A preprocessing data file is a text file with significant lines indicating +how should be preprocessed either a specific source or all sources not +mentioned in other lines. A significant line is a nonempty, non-comment line. +Comments are similar to Ada comments. + +Each significant line starts with either a literal string or the character '*'. +A literal string is the file name (without directory information) of the source +to preprocess. A character '*' indicates the preprocessing for all the sources +that are not specified explicitly on other lines (order of the lines is not +significant). It is an error to have two lines with the same file name or two +lines starting with the character '*'. + +After the file name or the character '*', another optional literal string +indicating the file name of the definition file to be used for preprocessing +(@ref{b2,,Form of Definitions File}). The definition files are found by the +compiler in one of the source directories. In some cases, when compiling +a source in a directory other than the current directory, if the definition +file is in the current directory, it may be necessary to add the current +directory as a source directory through switch -I., otherwise +the compiler would not find the definition file. + +Then, optionally, switches similar to those of @cite{gnatprep} may +be found. Those switches are: + + +@table @asis + +@item @code{-b} + +Causes both preprocessor lines and the lines deleted by +preprocessing to be replaced by blank lines, preserving the line number. +This switch is always implied; however, if specified after @emph{-c} +it cancels the effect of @emph{-c}. + +@item @code{-c} + +Causes both preprocessor lines and the lines deleted +by preprocessing to be retained as comments marked +with the special string '@cite{--!}'. + +@item @code{-Dsymbol=@emph{value}} + +Define or redefine a symbol, associated with value. A symbol is an Ada +identifier, or an Ada reserved word, with the exception of @cite{if}, +@cite{else}, @cite{elsif}, @cite{end}, @cite{and}, @cite{or} and @cite{then}. +@cite{value} is either a literal string, an Ada identifier or any Ada reserved +word. A symbol declared with this switch replaces a symbol with the +same name defined in a definition file. + +@item @code{-s} + +Causes a sorted list of symbol names and values to be +listed on the standard output file. + +@item @code{-u} + +Causes undefined symbols to be treated as having the value @cite{FALSE} +in the context +of a preprocessor test. In the absence of this option, an undefined symbol in +a @cite{#if} or @cite{#elsif} test will be treated as an error. +@end table + +Examples of valid lines in a preprocessor data file: + +@example +"toto.adb" "prep.def" -u +-- preprocess "toto.adb", using definition file "prep.def", +-- undefined symbol are False. + +* -c -DVERSION=V101 +-- preprocess all other sources without a definition file; +-- suppressed lined are commented; symbol VERSION has the value V101. + +"titi.adb" "prep2.def" -s +-- preprocess "titi.adb", using definition file "prep2.def"; +-- list all symbols with their values. +@end example +@end table + +@geindex -gnateD (gcc) + + +@table @asis + +@item @code{-gnateDsymbol[=value]} + +Define or redefine a preprocessing symbol, associated with value. If no value +is given on the command line, then the value of the symbol is @cite{True}. +A symbol is an identifier, following normal Ada (case-insensitive) +rules for its syntax, and value is either an arbitrary string between double +quotes or any sequence (including an empty sequence) of characters from the +set (letters, digits, period, underline). +Ada reserved words may be used as symbols, with the exceptions of @cite{if}, +@cite{else}, @cite{elsif}, @cite{end}, @cite{and}, @cite{or} and @cite{then}. + +Examples: + +@example +-gnateDToto=Titi +-gnateDFoo +-gnateDFoo=\"Foo-Bar\" +@end example + +A symbol declared with this switch on the command line replaces a +symbol with the same name either in a definition file or specified with a +switch -D in the preprocessor data file. + +This switch is similar to switch @emph{-D} of @cite{gnatprep}. + +@item @code{-gnateG} + +When integrated preprocessing is performed and the preprocessor modifies +the source text, write the result of this preprocessing into a file +<source>.prep. +@end table + +@node Mixed Language Programming,GNAT and Other Compilation Models,Conditional Compilation,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model mixed-language-programming}@anchor{46}@anchor{gnat_ugn/the_gnat_compilation_model id61}@anchor{b7} @section Mixed Language Programming -@cindex Mixed Language Programming -@noindent + +@geindex Mixed Language Programming + This section describes how to develop a mixed-language program, -specifically one that comprises units in both Ada and C. +with a focus on combining Ada with C or C++. @menu -* Interfacing to C:: -* Calling Conventions:: +* Interfacing to C:: +* Calling Conventions:: +* Building Mixed Ada and C++ Programs:: +* Generating Ada Bindings for C and C++ headers:: + @end menu -@node Interfacing to C +@node Interfacing to C,Calling Conventions,,Mixed Language Programming +@anchor{gnat_ugn/the_gnat_compilation_model interfacing-to-c}@anchor{b8}@anchor{gnat_ugn/the_gnat_compilation_model id62}@anchor{b9} @subsection Interfacing to C -@noindent + + Interfacing Ada with a foreign language such as C involves using compiler directives to import and/or export entity definitions in each -language---using @code{extern} statements in C, for instance, and the -@code{Import}, @code{Export}, and @code{Convention} pragmas in Ada. +language -- using @cite{extern} statements in C, for instance, and the +@cite{Import}, @cite{Export}, and @cite{Convention} pragmas in Ada. A full treatment of these topics is provided in Appendix B, section 1 of the Ada Reference Manual. @@ -2071,16 +5282,18 @@ sources and some foreign language sources, depending on whether or not the main subprogram is written in Ada. Here is a source example with the main subprogram in Ada: -@smallexample +@example /* file1.c */ #include <stdio.h> void print_num (int num) @{ - printf ("num is %d.\n", num); + printf ("num is %d.\\n", num); return; @} +@end example +@example /* file2.c */ /* num_from_Ada is declared in my_main.adb */ @@ -2090,9 +5303,9 @@ int get_num (void) @{ return num_from_Ada; @} -@end smallexample +@end example -@smallexample @c ada +@example -- my_main.adb procedure My_Main is @@ -2113,59 +5326,68 @@ procedure My_Main is begin Print_Num (Get_Num); end My_Main; -@end smallexample +@end example -@enumerate -@item -To build this example, first compile the foreign language files to +To build this example: + + +@itemize * + +@item +First compile the foreign language files to generate object files: -@smallexample -gcc -c file1.c -gcc -c file2.c -@end smallexample -@item +@example +$ gcc -c file1.c +$ gcc -c file2.c +@end example + +@item Then, compile the Ada units to produce a set of object files and ALI files: -@smallexample -gnatmake -c my_main.adb -@end smallexample -@item +@example +$ gnatmake -c my_main.adb +@end example + +@item Run the Ada binder on the Ada main program: -@smallexample -gnatbind my_main.ali -@end smallexample -@item +@example +$ gnatbind my_main.ali +@end example + +@item Link the Ada main program, the Ada objects and the other language objects: -@smallexample -gnatlink my_main.ali file1.o file2.o -@end smallexample -@end enumerate + +@example +$ gnatlink my_main.ali file1.o file2.o +@end example +@end itemize The last three steps can be grouped in a single command: -@smallexample -gnatmake my_main.adb -largs file1.o file2.o -@end smallexample -@cindex Binder output file -@noindent +@example +$ gnatmake my_main.adb -largs file1.o file2.o +@end example + +@geindex Binder output file + If the main program is in a language other than Ada, then you may have more than one entry point into the Ada subsystem. You must use a special binder option to generate callable routines that initialize and -finalize the Ada units (@pxref{Binding with Non-Ada Main Programs}). +finalize the Ada units (@ref{ba,,Binding with Non-Ada Main Programs}). Calls to the initialization and finalization routines must be inserted in the main program, or some other appropriate point in the code. The call to initialize the Ada units must occur before the first Ada subprogram is called, and the call to finalize the Ada units must occur after the last Ada subprogram returns. The binder will place the initialization and finalization subprograms into the -@file{b~@var{xxx}.adb} file where they can be accessed by your C +@code{b~xxx.adb} file where they can be accessed by your C sources. To illustrate, we have the following example: -@smallexample +@example /* main.c */ extern void adainit (void); extern void adafinal (void); @@ -2174,26 +5396,29 @@ extern int sub (int, int); int main (int argc, char *argv[]) @{ - int a = 21, b = 7; + int a = 21, b = 7; - adainit(); + adainit(); - /* Should print "21 + 7 = 28" */ - printf ("%d + %d = %d\n", a, b, add (a, b)); - /* Should print "21 - 7 = 14" */ - printf ("%d - %d = %d\n", a, b, sub (a, b)); + /* Should print "21 + 7 = 28" */ + printf ("%d + %d = %d\\n", a, b, add (a, b)); - adafinal(); + /* Should print "21 - 7 = 14" */ + printf ("%d - %d = %d\\n", a, b, sub (a, b)); + + adafinal(); @} -@end smallexample +@end example -@smallexample @c ada +@example -- unit1.ads package Unit1 is function Add (A, B : Integer) return Integer; pragma Export (C, Add, "add"); end Unit1; +@end example +@example -- unit1.adb package body Unit1 is function Add (A, B : Integer) return Integer is @@ -2201,13 +5426,17 @@ package body Unit1 is return A + B; end Add; end Unit1; +@end example +@example -- unit2.ads package Unit2 is function Sub (A, B : Integer) return Integer; pragma Export (C, Sub, "sub"); end Unit2; +@end example +@example -- unit2.adb package body Unit2 is function Sub (A, B : Integer) return Integer is @@ -2215,61 +5444,78 @@ package body Unit2 is return A - B; end Sub; end Unit2; -@end smallexample +@end example -@enumerate -@item The build procedure for this application is similar to the last -example's. First, compile the foreign language files to generate object -files: -@smallexample -gcc -c main.c -@end smallexample +example's: -@item + +@itemize * + +@item +First, compile the foreign language files to generate object files: + +@example +$ gcc -c main.c +@end example + +@item Next, compile the Ada units to produce a set of object files and ALI files: -@smallexample -gnatmake -c unit1.adb -gnatmake -c unit2.adb -@end smallexample -@item +@example +$ gnatmake -c unit1.adb +$ gnatmake -c unit2.adb +@end example + +@item Run the Ada binder on every generated ALI file. Make sure to use the -@option{-n} option to specify a foreign main program: -@smallexample -gnatbind -n unit1.ali unit2.ali -@end smallexample +@code{-n} option to specify a foreign main program: -@item +@example +$ gnatbind -n unit1.ali unit2.ali +@end example + +@item Link the Ada main program, the Ada objects and the foreign language objects. You need only list the last ALI file here: -@smallexample -gnatlink unit2.ali main.o -o exec_file -@end smallexample -This procedure yields a binary executable called @file{exec_file}. -@end enumerate +@example +$ gnatlink unit2.ali main.o -o exec_file +@end example + +This procedure yields a binary executable called @code{exec_file}. +@end itemize -@noindent Depending on the circumstances (for example when your non-Ada main object -does not provide symbol @code{main}), you may also need to instruct the +does not provide symbol @cite{main}), you may also need to instruct the GNAT linker not to include the standard startup objects by passing the -@option{-nostartfiles} switch to @command{gnatlink}. +@code{-nostartfiles} switch to @cite{gnatlink}. -@node Calling Conventions +@node Calling Conventions,Building Mixed Ada and C++ Programs,Interfacing to C,Mixed Language Programming +@anchor{gnat_ugn/the_gnat_compilation_model calling-conventions}@anchor{bb}@anchor{gnat_ugn/the_gnat_compilation_model id63}@anchor{bc} @subsection Calling Conventions -@cindex Foreign Languages -@cindex Calling Conventions + + +@geindex Foreign Languages + +@geindex Calling Conventions + GNAT follows standard calling sequence conventions and will thus interface to any other language that also follows these conventions. The following Convention identifiers are recognized by GNAT: -@table @code -@cindex Interfacing to Ada -@cindex Other Ada compilers -@cindex Convention Ada -@item Ada +@geindex Interfacing to Ada + +@geindex Other Ada compilers + +@geindex Convention Ada + + +@table @asis + +@item @emph{Ada} + This indicates that the standard Ada calling sequence will be used and all Ada data items may be passed without any limitations in the case where GNAT is used to generate both the caller and callee. It is also @@ -2297,86 +5543,149 @@ However, it is not possible to mix the tasking run time of GNAT and HP Ada 83, All the tasking operations must either be entirely within GNAT compiled sections of the program, or entirely within HP Ada 83 compiled sections of the program. +@end table + +@geindex Interfacing to Assembly + +@geindex Convention Assembler + + +@table @asis + +@item @emph{Assembler} -@cindex Interfacing to Assembly -@cindex Convention Assembler -@item Assembler Specifies assembler as the convention. In practice this has the same effect as convention Ada (but is not equivalent in the sense of being considered the same convention). +@end table + +@geindex Convention Asm + +@geindex Asm + + +@table @asis + +@item @emph{Asm} -@cindex Convention Asm -@findex Asm -@item Asm Equivalent to Assembler. -@cindex Interfacing to COBOL -@cindex Convention COBOL -@findex COBOL -@item COBOL +@geindex Interfacing to COBOL + +@geindex Convention COBOL +@end table + +@geindex COBOL + + +@table @asis + +@item @emph{COBOL} + Data will be passed according to the conventions described in section B.4 of the Ada Reference Manual. +@end table + +@geindex C + +@geindex Interfacing to C + +@geindex Convention C + + +@table @asis + +@item @emph{C} -@findex C -@cindex Interfacing to C -@cindex Convention C -@item C Data will be passed according to the conventions described in section B.3 of the Ada Reference Manual. -A note on interfacing to a C ``varargs'' function: -@findex C varargs function -@cindex Interfacing to C varargs function -@cindex varargs function interfaces +A note on interfacing to a C 'varargs' function: -@itemize @bullet -@item -In C, @code{varargs} allows a function to take a variable number of +@quotation + +@geindex C varargs function + +@geindex Interfacing to C varargs function + +@geindex varargs function interfaces + +In C, @cite{varargs} allows a function to take a variable number of arguments. There is no direct equivalent in this to Ada. One approach that can be used is to create a C wrapper for each different profile and then interface to this C wrapper. For -example, to print an @code{int} value using @code{printf}, -create a C function @code{printfi} that takes two arguments, a -pointer to a string and an int, and calls @code{printf}. -Then in the Ada program, use pragma @code{Import} to -interface to @code{printfi}. +example, to print an @cite{int} value using @cite{printf}, +create a C function @cite{printfi} that takes two arguments, a +pointer to a string and an int, and calls @cite{printf}. +Then in the Ada program, use pragma @cite{Import} to +interface to @cite{printfi}. -@item It may work on some platforms to directly interface to -a @code{varargs} function by providing a specific Ada profile +a @cite{varargs} function by providing a specific Ada profile for a particular call. However, this does not work on all platforms, since there is no guarantee that the calling sequence for a two argument normal C function -is the same as for calling a @code{varargs} C function with +is the same as for calling a @cite{varargs} C function with the same two arguments. -@end itemize +@end quotation +@end table + +@geindex Convention Default + +@geindex Default + + +@table @asis + +@item @emph{Default} -@cindex Convention Default -@findex Default -@item Default Equivalent to C. +@end table + +@geindex Convention External + +@geindex External + + +@table @asis + +@item @emph{External} -@cindex Convention External -@findex External -@item External Equivalent to C. +@end table + +@geindex C++ + +@geindex Interfacing to C++ + +@geindex Convention C++ + + +@table @asis + +@item @emph{C_Plus_Plus (or CPP)} -@findex C++ -@cindex Interfacing to C++ -@cindex Convention C++ -@item C_Plus_Plus (or CPP) This stands for C++. For most purposes this is identical to C. See the separate description of the specialized GNAT pragmas relating to C++ interfacing for further details. +@end table + +@geindex Fortran + +@geindex Interfacing to Fortran + +@geindex Convention Fortran + + +@table @asis + +@item @emph{Fortran} -@findex Fortran -@cindex Interfacing to Fortran -@cindex Convention Fortran -@item Fortran Data will be passed according to the conventions described in section B.5 of the Ada Reference Manual. -@item Intrinsic +@item @emph{Intrinsic} + This applies to an intrinsic operation, as defined in the Ada Reference Manual. If a pragma Import (Intrinsic) applies to a subprogram, this means that the body of the subprogram is provided by the compiler itself, @@ -2384,257 +5693,298 @@ usually by means of an efficient code sequence, and that the user does not supply an explicit body for it. In an application program, the pragma may be applied to the following sets of names: -@itemize @bullet -@item -Rotate_Left, Rotate_Right, Shift_Left, Shift_Right, -Shift_Right_Arithmetic. The corresponding subprogram declaration must have + +@itemize * + +@item +Rotate_Left, Rotate_Right, Shift_Left, Shift_Right, Shift_Right_Arithmetic. +The corresponding subprogram declaration must have two formal parameters. The first one must be a signed integer type or a modular type with a binary modulus, and the second parameter must be of type Natural. The return type must be the same as the type of the first argument. The size of this type can only be 8, 16, 32, or 64. -@item -Binary arithmetic operators: ``+'', ``-'', ``*'', ``/'' +@item +Binary arithmetic operators: '+', '-', '*', '/'. The corresponding operator declaration must have parameters and result type that have the same root numeric type (for example, all three are long_float types). This simplifies the definition of operations that use type checking to perform dimensional checks: +@end itemize -@smallexample @c ada -@b{type} Distance @b{is} @b{new} Long_Float; -@b{type} Time @b{is} @b{new} Long_Float; -@b{type} Velocity @b{is} @b{new} Long_Float; -@b{function} "/" (D : Distance; T : Time) - @b{return} Velocity; -@b{pragma} Import (Intrinsic, "/"); -@end smallexample - -@noindent -This common idiom is often programmed with a generic definition and an -explicit body. The pragma makes it simpler to introduce such declarations. -It incurs no overhead in compilation time or code size, because it is -implemented as a single machine instruction. - -@item -General subprogram entities, to bind an Ada subprogram declaration to +@c code-block: ada +@c +@c type Distance is new Long_Float; +@c type Time is new Long_Float; +@c type Velocity is new Long_Float; +@c function "/" (D : Distance; T : Time) +@c return Velocity; +@c pragma Import (Intrinsic, "/"); +@c +@c This common idiom is often programmed with a generic definition and an +@c explicit body. The pragma makes it simpler to introduce such declarations. +@c It incurs no overhead in compilation time or code size, because it is +@c implemented as a single machine instruction. + + +@itemize * + +@item +General subprogram entities. This is used to bind an Ada subprogram +declaration to a compiler builtin by name with back-ends where such interfaces are -available. A typical example is the set of ``__builtin'' functions +available. A typical example is the set of @cite{__builtin} functions exposed by the GCC back-end, as in the following example: -@smallexample @c ada - @b{function} builtin_sqrt (F : Float) @b{return} Float; - @b{pragma} Import (Intrinsic, builtin_sqrt, "__builtin_sqrtf"); -@end smallexample +@example +function builtin_sqrt (F : Float) return Float; +pragma Import (Intrinsic, builtin_sqrt, "__builtin_sqrtf"); +@end example Most of the GCC builtins are accessible this way, and as for other import conventions (e.g. C), it is the user's responsibility to ensure that the Ada subprogram profile matches the underlying builtin expectations. @end itemize +@end table + +@geindex Stdcall -@noindent +@geindex Convention Stdcall + + +@table @asis + +@item @emph{Stdcall} -@findex Stdcall -@cindex Convention Stdcall -@item Stdcall This is relevant only to Windows XP/2000/NT implementations of GNAT, -and specifies that the @code{Stdcall} calling sequence will be used, +and specifies that the @cite{Stdcall} calling sequence will be used, as defined by the NT API. Nevertheless, to ease building -cross-platform bindings this convention will be handled as a @code{C} calling +cross-platform bindings this convention will be handled as a @cite{C} calling convention on non-Windows platforms. +@end table + +@geindex DLL + +@geindex Convention DLL + -@findex DLL -@cindex Convention DLL -@item DLL -This is equivalent to @code{Stdcall}. +@table @asis + +@item @emph{DLL} + +This is equivalent to @cite{Stdcall}. +@end table + +@geindex Win32 + +@geindex Convention Win32 + + +@table @asis + +@item @emph{Win32} + +This is equivalent to @cite{Stdcall}. +@end table + +@geindex Stubbed + +@geindex Convention Stubbed + + +@table @asis -@findex Win32 -@cindex Convention Win32 -@item Win32 -This is equivalent to @code{Stdcall}. +@item @emph{Stubbed} -@findex Stubbed -@cindex Convention Stubbed -@item Stubbed This is a special convention that indicates that the compiler -should provide a stub body that raises @code{Program_Error}. +should provide a stub body that raises @cite{Program_Error}. @end table -@noindent -GNAT additionally provides a useful pragma @code{Convention_Identifier} +GNAT additionally provides a useful pragma @cite{Convention_Identifier} that can be used to parameterize conventions and allow additional synonyms to be specified. For example if you have legacy code in which the convention identifier Fortran77 was used for Fortran, you can use the configuration pragma: -@smallexample @c ada -@b{pragma} Convention_Identifier (Fortran77, Fortran); -@end smallexample +@example +pragma Convention_Identifier (Fortran77, Fortran); +@end example -@noindent And from now on the identifier Fortran77 may be used as a convention -identifier (for example in an @code{Import} pragma) with the same +identifier (for example in an @cite{Import} pragma) with the same meaning as Fortran. -@node Building Mixed Ada & C++ Programs -@section Building Mixed Ada and C++ Programs +@node Building Mixed Ada and C++ Programs,Generating Ada Bindings for C and C++ headers,Calling Conventions,Mixed Language Programming +@anchor{gnat_ugn/the_gnat_compilation_model id64}@anchor{bd}@anchor{gnat_ugn/the_gnat_compilation_model building-mixed-ada-and-c-programs}@anchor{be} +@subsection Building Mixed Ada and C++ Programs + -@noindent A programmer inexperienced with mixed-language development may find that building an application containing both Ada and C++ code can be a -challenge. This section gives a few -hints that should make this task easier. The first section addresses -the differences between interfacing with C and interfacing with C++. -The second section -looks into the delicate problem of linking the complete application from -its Ada and C++ parts. The last section gives some hints on how the GNAT -run-time library can be adapted in order to allow inter-language dispatching -with a new C++ compiler. +challenge. This section gives a few hints that should make this task easier. @menu -* Interfacing to C++:: -* Linking a Mixed C++ & Ada Program:: -* A Simple Example:: -* Interfacing with C++ constructors:: -* Interfacing with C++ at the Class Level:: +* Interfacing to C++:: +* Linking a Mixed C++ & Ada Program:: +* A Simple Example:: +* Interfacing with C++ constructors:: +* Interfacing with C++ at the Class Level:: + @end menu -@node Interfacing to C++ -@subsection Interfacing to C++ +@node Interfacing to C++,Linking a Mixed C++ & Ada Program,,Building Mixed Ada and C++ Programs +@anchor{gnat_ugn/the_gnat_compilation_model id65}@anchor{bf}@anchor{gnat_ugn/the_gnat_compilation_model id66}@anchor{c0} +@subsubsection Interfacing to C++ + -@noindent GNAT supports interfacing with the G++ compiler (or any C++ compiler generating code that is compatible with the G++ Application Binary -Interface ---see http://www.codesourcery.com/archives/cxx-abi). +Interface ---see @indicateurl{http://www.codesourcery.com/archives/cxx-abi}). -@noindent Interfacing can be done at 3 levels: simple data, subprograms, and -classes. In the first two cases, GNAT offers a specific @code{Convention -C_Plus_Plus} (or @code{CPP}) that behaves exactly like @code{Convention C}. +classes. In the first two cases, GNAT offers a specific @cite{Convention C_Plus_Plus} +(or @cite{CPP}) that behaves exactly like @cite{Convention C}. Usually, C++ mangles the names of subprograms. To generate proper mangled -names automatically, see @ref{Generating Ada Bindings for C and C++ headers}). +names automatically, see @ref{1b,,Generating Ada Bindings for C and C++ headers}). This problem can also be addressed manually in two ways: -@itemize @bullet -@item + +@itemize * + +@item by modifying the C++ code in order to force a C convention using -the @code{extern "C"} syntax. +the @cite{extern "C"} syntax. -@item -by figuring out the mangled name (using e.g. @command{nm}) and using it as the +@item +by figuring out the mangled name (using e.g. @emph{nm}) and using it as the Link_Name argument of the pragma import. @end itemize -@noindent Interfacing at the class level can be achieved by using the GNAT specific -pragmas such as @code{CPP_Constructor}. @xref{Interfacing to C++,,, -gnat_rm, GNAT Reference Manual}, for additional information. +pragmas such as @cite{CPP_Constructor}. See the @cite{GNAT_Reference_Manual} for additional information. + +@node Linking a Mixed C++ & Ada Program,A Simple Example,Interfacing to C++,Building Mixed Ada and C++ Programs +@anchor{gnat_ugn/the_gnat_compilation_model linking-a-mixed-c-ada-program}@anchor{c1}@anchor{gnat_ugn/the_gnat_compilation_model linking-a-mixed-c-and-ada-program}@anchor{c2} +@subsubsection Linking a Mixed C++ & Ada Program -@node Linking a Mixed C++ & Ada Program -@subsection Linking a Mixed C++ & Ada Program -@noindent Usually the linker of the C++ development system must be used to link mixed applications because most C++ systems will resolve elaboration issues (such as calling constructors on global class instances) transparently during the link phase. GNAT has been adapted to ease the use of a foreign linker for the last phase. Three cases can be considered: -@enumerate -@item + +@itemize * + +@item Using GNAT and G++ (GNU C++ compiler) from the same GCC installation: The C++ linker can simply be called by using the C++ specific driver -called @code{g++}. +called @cite{g++}. Note that if the C++ code uses inline functions, you will need to -compile your C++ code with the @code{-fkeep-inline-functions} switch in +compile your C++ code with the @cite{-fkeep-inline-functions} switch in order to provide an existing function implementation that the Ada code can link with. -@smallexample +@example $ g++ -c -fkeep-inline-functions file1.C $ g++ -c -fkeep-inline-functions file2.C $ gnatmake ada_unit -largs file1.o file2.o --LINK=g++ -@end smallexample +@end example -@item +@item Using GNAT and G++ from two different GCC installations: If both -compilers are on the @env{PATH}, the previous method may be used. It is +compilers are on the :envvar`PATH`, the previous method may be used. It is important to note that environment variables such as -@env{C_INCLUDE_PATH}, @env{GCC_EXEC_PREFIX}, @env{BINUTILS_ROOT}, and -@env{GCC_ROOT} will affect both compilers +@geindex C_INCLUDE_PATH +@geindex environment variable; C_INCLUDE_PATH +@code{C_INCLUDE_PATH}, +@geindex GCC_EXEC_PREFIX +@geindex environment variable; GCC_EXEC_PREFIX +@code{GCC_EXEC_PREFIX}, +@geindex BINUTILS_ROOT +@geindex environment variable; BINUTILS_ROOT +@code{BINUTILS_ROOT}, and +@geindex GCC_ROOT +@geindex environment variable; GCC_ROOT +@code{GCC_ROOT} will affect both compilers at the same time and may make one of the two compilers operate improperly if set during invocation of the wrong compiler. It is also -very important that the linker uses the proper @file{libgcc.a} GCC +very important that the linker uses the proper @code{libgcc.a} GCC library -- that is, the one from the C++ compiler installation. The -implicit link command as suggested in the @command{gnatmake} command +implicit link command as suggested in the @cite{gnatmake} command from the former example can be replaced by an explicit link command with the full-verbosity option in order to verify which library is used: -@smallexample + +@example $ gnatbind ada_unit $ gnatlink -v -v ada_unit file1.o file2.o --LINK=c++ -@end smallexample +@end example + If there is a problem due to interfering environment variables, it can be worked around by using an intermediate script. The following example shows the proper script to use when GNAT has not been installed at its default location and g++ has been installed at its default location: -@smallexample +@example $ cat ./my_script #!/bin/sh unset BINUTILS_ROOT unset GCC_ROOT c++ $* $ gnatlink -v -v ada_unit file1.o file2.o --LINK=./my_script -@end smallexample +@end example -@item +@item Using a non-GNU C++ compiler: The commands previously described can be used to insure that the C++ linker is used. Nonetheless, you need to add a few more parameters to the link command line, depending on the exception mechanism used. -If the @code{setjmp/longjmp} exception mechanism is used, only the paths +If the @cite{setjmp/longjmp} exception mechanism is used, only the paths to the libgcc libraries are required: -@smallexample +@example $ cat ./my_script #!/bin/sh CC $* `gcc -print-file-name=libgcc.a` `gcc -print-file-name=libgcc_eh.a` $ gnatlink ada_unit file1.o file2.o --LINK=./my_script -@end smallexample +@end example -Where CC is the name of the non-GNU C++ compiler. +where CC is the name of the non-GNU C++ compiler. -If the @code{zero cost} exception mechanism is used, and the platform -supports automatic registration of exception tables (e.g.@: Solaris), +If the @cite{zero cost} exception mechanism is used, and the platform +supports automatic registration of exception tables (e.g., Solaris), paths to more objects are required: -@smallexample +@example $ cat ./my_script #!/bin/sh -CC `gcc -print-file-name=crtbegin.o` $* \ -`gcc -print-file-name=libgcc.a` `gcc -print-file-name=libgcc_eh.a` \ +CC `gcc -print-file-name=crtbegin.o` $* \\ +`gcc -print-file-name=libgcc.a` `gcc -print-file-name=libgcc_eh.a` \\ `gcc -print-file-name=crtend.o` $ gnatlink ada_unit file1.o file2.o --LINK=./my_script -@end smallexample +@end example -If the @code{zero cost} exception mechanism is used, and the platform -doesn't support automatic registration of exception tables (e.g.@: HP-UX +If the "zero cost exception" mechanism is used, and the platform +doesn't support automatic registration of exception tables (e.g., HP-UX or AIX), the simple approach described above will not work and a pre-linking phase using GNAT will be necessary. +@end itemize -@end enumerate - -Another alternative is to use the @command{gprbuild} multi-language builder +Another alternative is to use the @strong{gprbuild} multi-language builder which has a large knowledge base and knows how to link Ada and C++ code together automatically in most cases. -@node A Simple Example -@subsection A Simple Example -@noindent +@node A Simple Example,Interfacing with C++ constructors,Linking a Mixed C++ & Ada Program,Building Mixed Ada and C++ Programs +@anchor{gnat_ugn/the_gnat_compilation_model id67}@anchor{c3}@anchor{gnat_ugn/the_gnat_compilation_model a-simple-example}@anchor{c4} +@subsubsection A Simple Example + + The following example, provided as part of the GNAT examples, shows how to achieve procedural interfacing between Ada and C++ in both directions. The C++ class A has two methods. The first method is exported @@ -2645,21 +5995,19 @@ subprogram, in turn, calls the C++ method. So, starting from the C++ main program, the process passes back and forth between the two languages. -@noindent Here are the compilation commands: -@smallexample + +@example $ gnatmake -c simple_cpp_interface $ g++ -c cpp_main.C $ g++ -c ex7.C $ gnatbind -n simple_cpp_interface -$ gnatlink simple_cpp_interface -o cpp_main --LINK=g++ - -lstdc++ ex7.o cpp_main.o -@end smallexample +$ gnatlink simple_cpp_interface -o cpp_main --LINK=g++ -lstdc++ ex7.o cpp_main.o +@end example -@noindent Here are the corresponding sources: -@smallexample +@example //cpp_main.C #include "ex7.h" @@ -2682,7 +6030,9 @@ int main () obj.method2 (3030); adafinal (); @} +@end example +@example //ex7.h class Origin @{ @@ -2696,7 +6046,9 @@ class A : public Origin @{ A(); int a_value; @}; +@end example +@example //ex7.C #include "ex7.h" @@ -2707,107 +6059,109 @@ extern "C" @{ void ada_method2 (A *t, int v);@} void A::method1 (void) @{ a_value = 2020; - printf ("in A::method1, a_value = %d \n",a_value); - + printf ("in A::method1, a_value = %d \\n",a_value); @} void A::method2 (int v) @{ ada_method2 (this, v); - printf ("in A::method2, a_value = %d \n",a_value); - + printf ("in A::method2, a_value = %d \\n",a_value); @} A::A(void) @{ a_value = 1010; - printf ("in A::A, a_value = %d \n",a_value); + printf ("in A::A, a_value = %d \\n",a_value); @} -@end smallexample +@end example + +@example +-- simple_cpp_interface.ads +with System; +package Simple_Cpp_Interface is + type A is limited + record + Vptr : System.Address; + O_Value : Integer; + A_Value : Integer; + end record; + pragma Convention (C, A); -@smallexample @c ada ---@i{ Ada sources} -@b{package} @b{body} Simple_Cpp_Interface @b{is} + procedure Method1 (This : in out A); + pragma Import (C, Method1); - @b{procedure} Ada_Method2 (This : @b{in} @b{out} A; V : Integer) @b{is} - @b{begin} - Method1 (This); - This.A_Value := V; - @b{end} Ada_Method2; + procedure Ada_Method2 (This : in out A; V : Integer); + pragma Export (C, Ada_Method2); -@b{end} Simple_Cpp_Interface; +end Simple_Cpp_Interface; +@end example -@b{with} System; -@b{package} Simple_Cpp_Interface @b{is} - @b{type} A @b{is} @b{limited} - @b{record} - Vptr : System.Address; - O_Value : Integer; - A_Value : Integer; - @b{end} @b{record}; - @b{pragma} Convention (C, A); +@example +-- simple_cpp_interface.adb +package body Simple_Cpp_Interface is - @b{procedure} Method1 (This : @b{in} @b{out} A); - @b{pragma} Import (C, Method1); + procedure Ada_Method2 (This : in out A; V : Integer) is + begin + Method1 (This); + This.A_Value := V; + end Ada_Method2; - @b{procedure} Ada_Method2 (This : @b{in} @b{out} A; V : Integer); - @b{pragma} Export (C, Ada_Method2); +end Simple_Cpp_Interface; +@end example -@b{end} Simple_Cpp_Interface; -@end smallexample +@node Interfacing with C++ constructors,Interfacing with C++ at the Class Level,A Simple Example,Building Mixed Ada and C++ Programs +@anchor{gnat_ugn/the_gnat_compilation_model id68}@anchor{c5}@anchor{gnat_ugn/the_gnat_compilation_model interfacing-with-c-constructors}@anchor{c6} +@subsubsection Interfacing with C++ constructors -@node Interfacing with C++ constructors -@subsection Interfacing with C++ constructors -@noindent In order to interface with C++ constructors GNAT provides the -@code{pragma CPP_Constructor} (@xref{Interfacing to C++,,, -gnat_rm, GNAT Reference Manual}, for additional information). +@cite{pragma CPP_Constructor} (see the @cite{GNAT_Reference_Manual} +for additional information). In this section we present some common uses of C++ constructors in mixed-languages programs in GNAT. Let us assume that we need to interface with the following C++ class: -@smallexample -@b{class} Root @{ -@b{public}: +@example +class Root @{ +public: int a_value; int b_value; - @b{virtual} int Get_Value (); + virtual int Get_Value (); Root(); // Default constructor Root(int v); // 1st non-default constructor Root(int v, int w); // 2nd non-default constructor @}; -@end smallexample +@end example For this purpose we can write the following package spec (further information on how to build this spec is available in -@ref{Interfacing with C++ at the Class Level} and -@ref{Generating Ada Bindings for C and C++ headers}). +@ref{c7,,Interfacing with C++ at the Class Level} and +@ref{1b,,Generating Ada Bindings for C and C++ headers}). -@smallexample @c ada -@b{with} Interfaces.C; @b{use} Interfaces.C; -@b{package} Pkg_Root @b{is} - @b{type} Root @b{is} @b{tagged} @b{limited} @b{record} +@example +with Interfaces.C; use Interfaces.C; +package Pkg_Root is + type Root is tagged limited record A_Value : int; B_Value : int; - @b{end} @b{record}; - @b{pragma} Import (CPP, Root); + end record; + pragma Import (CPP, Root); - @b{function} Get_Value (Obj : Root) @b{return} int; - @b{pragma} Import (CPP, Get_Value); + function Get_Value (Obj : Root) return int; + pragma Import (CPP, Get_Value); - @b{function} Constructor @b{return} Root; - @b{pragma} Cpp_Constructor (Constructor, "_ZN4RootC1Ev"); + function Constructor return Root; + pragma Cpp_Constructor (Constructor, "_ZN4RootC1Ev"); - @b{function} Constructor (v : Integer) @b{return} Root; - @b{pragma} Cpp_Constructor (Constructor, "_ZN4RootC1Ei"); + function Constructor (v : Integer) return Root; + pragma Cpp_Constructor (Constructor, "_ZN4RootC1Ei"); - @b{function} Constructor (v, w : Integer) @b{return} Root; - @b{pragma} Cpp_Constructor (Constructor, "_ZN4RootC1Eii"); -@b{end} Pkg_Root; -@end smallexample + function Constructor (v, w : Integer) return Root; + pragma Cpp_Constructor (Constructor, "_ZN4RootC1Eii"); +end Pkg_Root; +@end example On the Ada side the constructor is represented by a function (whose name is arbitrary) that returns the classwide type corresponding to @@ -2819,47 +6173,52 @@ properly initialized. Constructors can only appear in the following contexts: -@itemize @bullet -@item -On the right side of an initialization of an object of type @var{T}. -@item -On the right side of an initialization of a record component of type @var{T}. -@item + +@itemize * + +@item +On the right side of an initialization of an object of type @cite{T}. + +@item +On the right side of an initialization of a record component of type @cite{T}. + +@item In an Ada 2005 limited aggregate. -@item + +@item In an Ada 2005 nested limited aggregate. -@item + +@item In an Ada 2005 limited aggregate that initializes an object built in place by an extended return statement. @end itemize -@noindent In a declaration of an object whose type is a class imported from C++, either the default C++ constructor is implicitly called by GNAT, or else the required C++ constructor must be explicitly called in the expression that initializes the object. For example: -@smallexample @c ada - Obj1 : Root; - Obj2 : Root := Constructor; - Obj3 : Root := Constructor (v => 10); - Obj4 : Root := Constructor (30, 40); -@end smallexample +@example +Obj1 : Root; +Obj2 : Root := Constructor; +Obj3 : Root := Constructor (v => 10); +Obj4 : Root := Constructor (30, 40); +@end example The first two declarations are equivalent: in both cases the default C++ constructor is invoked (in the former case the call to the constructor is implicit, and in the latter case the call is explicit in the object -declaration). @code{Obj3} is initialized by the C++ non-default constructor -that takes an integer argument, and @code{Obj4} is initialized by the +declaration). @cite{Obj3} is initialized by the C++ non-default constructor +that takes an integer argument, and @cite{Obj4} is initialized by the non-default C++ constructor that takes two integers. Let us derive the imported C++ class in the Ada side. For example: -@smallexample @c ada - @b{type} DT @b{is} @b{new} Root @b{with} @b{record} - C_Value : Natural := 2009; - @b{end} @b{record}; -@end smallexample +@example +type DT is new Root with record + C_Value : Natural := 2009; +end record; +@end example In this case the components DT inherited from the C++ side must be initialized by a C++ constructor, and the additional Ada components @@ -2867,17 +6226,17 @@ of type DT are initialized by GNAT. The initialization of such an object is done either by default, or by means of a function returning an aggregate of type DT, or by means of an extension aggregate. -@smallexample @c ada - Obj5 : DT; - Obj6 : DT := Function_Returning_DT (50); - Obj7 : DT := (Constructor (30,40) @b{with} C_Value => 50); -@end smallexample +@example +Obj5 : DT; +Obj6 : DT := Function_Returning_DT (50); +Obj7 : DT := (Constructor (30,40) with C_Value => 50); +@end example -The declaration of @code{Obj5} invokes the default constructors: the +The declaration of @cite{Obj5} invokes the default constructors: the C++ default constructor of the parent type takes care of the initialization of the components inherited from Root, and GNAT takes care of the default initialization of the additional Ada components of type DT (that is, -@code{C_Value} is initialized to value 2009). The order of invocation of +@cite{C_Value} is initialized to value 2009). The order of invocation of the constructors is consistent with the order of elaboration required by Ada and C++. That is, the constructor of the parent type is always called before the constructor of the derived type. @@ -2885,71 +6244,73 @@ before the constructor of the derived type. Let us now consider a record that has components whose type is imported from C++. For example: -@smallexample @c ada - @b{type} Rec1 @b{is} @b{limited} @b{record} - Data1 : Root := Constructor (10); - Value : Natural := 1000; - @b{end} @b{record}; +@example +type Rec1 is limited record + Data1 : Root := Constructor (10); + Value : Natural := 1000; +end record; - @b{type} Rec2 (D : Integer := 20) @b{is} @b{limited} @b{record} - Rec : Rec1; - Data2 : Root := Constructor (D, 30); - @b{end} @b{record}; -@end smallexample +type Rec2 (D : Integer := 20) is limited record + Rec : Rec1; + Data2 : Root := Constructor (D, 30); +end record; +@end example -The initialization of an object of type @code{Rec2} will call the +The initialization of an object of type @cite{Rec2} will call the non-default C++ constructors specified for the imported components. For example: -@smallexample @c ada - Obj8 : Rec2 (40); -@end smallexample +@example +Obj8 : Rec2 (40); +@end example Using Ada 2005 we can use limited aggregates to initialize an object invoking C++ constructors that differ from those specified in the type declarations. For example: -@smallexample @c ada - Obj9 : Rec2 := (Rec => (Data1 => Constructor (15, 16), - @b{others} => <>), - @b{others} => <>); -@end smallexample +@example +Obj9 : Rec2 := (Rec => (Data1 => Constructor (15, 16), + others => <>), + others => <>); +@end example The above declaration uses an Ada 2005 limited aggregate to -initialize @code{Obj9}, and the C++ constructor that has two integer -arguments is invoked to initialize the @code{Data1} component instead -of the constructor specified in the declaration of type @code{Rec1}. In +initialize @cite{Obj9}, and the C++ constructor that has two integer +arguments is invoked to initialize the @cite{Data1} component instead +of the constructor specified in the declaration of type @cite{Rec1}. In Ada 2005 the box in the aggregate indicates that unspecified components are initialized using the expression (if any) available in the component -declaration. That is, in this case discriminant @code{D} is initialized -to value @code{20}, @code{Value} is initialized to value 1000, and the +declaration. That is, in this case discriminant @cite{D} is initialized +to value @cite{20}, @cite{Value} is initialized to value 1000, and the non-default C++ constructor that handles two integers takes care of -initializing component @code{Data2} with values @code{20,30}. +initializing component @cite{Data2} with values @cite{20@comma{}30}. In Ada 2005 we can use the extended return statement to build the Ada equivalent to C++ non-default constructors. For example: -@smallexample @c ada - @b{function} Constructor (V : Integer) @b{return} Rec2 @b{is} - @b{begin} - @b{return} Obj : Rec2 := (Rec => (Data1 => Constructor (V, 20), - @b{others} => <>), - @b{others} => <>) @b{do} - --@i{ Further actions required for construction of} - --@i{ objects of type Rec2} - ... - @b{end} @b{record}; - @b{end} Constructor; -@end smallexample +@example +function Constructor (V : Integer) return Rec2 is +begin + return Obj : Rec2 := (Rec => (Data1 => Constructor (V, 20), + others => <>), + others => <>) do + -- Further actions required for construction of + -- objects of type Rec2 + ... + end record; +end Constructor; +@end example In this example the extended return statement construct is used to build in place the returned object whose components are initialized by means of a limited aggregate. Any further action associated with the constructor can be placed inside the construct. -@node Interfacing with C++ at the Class Level -@subsection Interfacing with C++ at the Class Level -@noindent +@node Interfacing with C++ at the Class Level,,Interfacing with C++ constructors,Building Mixed Ada and C++ Programs +@anchor{gnat_ugn/the_gnat_compilation_model interfacing-with-c-at-the-class-level}@anchor{c7}@anchor{gnat_ugn/the_gnat_compilation_model id69}@anchor{c8} +@subsubsection Interfacing with C++ at the Class Level + + In this section we demonstrate the GNAT features for interfacing with C++ by means of an example making use of Ada 2005 abstract interface types. This example consists of a classification of animals; classes @@ -2959,104 +6320,104 @@ classifications. We first demonstrate a case in which the types and constructors are defined on the C++ side and imported from the Ada side, and latter the reverse case. -The root of our derivation will be the @code{Animal} class, with a -single private attribute (the @code{Age} of the animal), a constructor, +The root of our derivation will be the @cite{Animal} class, with a +single private attribute (the @cite{Age} of the animal), a constructor, and two public primitives to set and get the value of this attribute. -@smallexample -@b{class} Animal @{ - @b{public}: - @b{virtual} void Set_Age (int New_Age); - @b{virtual} int Age (); +@example +class Animal @{ + public: + virtual void Set_Age (int New_Age); + virtual int Age (); Animal() @{Age_Count = 0;@}; - @b{private}: + private: int Age_Count; @}; -@end smallexample +@end example Abstract interface types are defined in C++ by means of classes with pure virtual functions and no data members. In our example we will use two -interfaces that provide support for the common management of @code{Carnivore} -and @code{Domestic} animals: +interfaces that provide support for the common management of @cite{Carnivore} +and @cite{Domestic} animals: -@smallexample -@b{class} Carnivore @{ -@b{public}: - @b{virtual} int Number_Of_Teeth () = 0; +@example +class Carnivore @{ +public: + virtual int Number_Of_Teeth () = 0; @}; -@b{class} Domestic @{ -@b{public}: - @b{virtual void} Set_Owner (char* Name) = 0; +class Domestic @{ +public: + virtual void Set_Owner (char* Name) = 0; @}; -@end smallexample +@end example -Using these declarations, we can now say that a @code{Dog} is an animal that is +Using these declarations, we can now say that a @cite{Dog} is an animal that is both Carnivore and Domestic, that is: -@smallexample -@b{class} Dog : Animal, Carnivore, Domestic @{ - @b{public}: - @b{virtual} int Number_Of_Teeth (); - @b{virtual} void Set_Owner (char* Name); +@example +class Dog : Animal, Carnivore, Domestic @{ + public: + virtual int Number_Of_Teeth (); + virtual void Set_Owner (char* Name); Dog(); // Constructor - @b{private}: + private: int Tooth_Count; char *Owner; @}; -@end smallexample +@end example In the following examples we will assume that the previous declarations are -located in a file named @code{animals.h}. The following package demonstrates +located in a file named @cite{animals.h}. The following package demonstrates how to import these C++ declarations from the Ada side: -@smallexample @c ada -@b{with} Interfaces.C.Strings; @b{use} Interfaces.C.Strings; -@b{package} Animals @b{is} - @b{type} Carnivore @b{is} @b{limited} interface; - @b{pragma} Convention (C_Plus_Plus, Carnivore); - @b{function} Number_Of_Teeth (X : Carnivore) - @b{return} Natural @b{is} @b{abstract}; - - @b{type} Domestic @b{is} @b{limited} interface; - @b{pragma} Convention (C_Plus_Plus, Domestic); - @b{procedure} Set_Owner - (X : @b{in} @b{out} Domestic; - Name : Chars_Ptr) @b{is} @b{abstract}; - - @b{type} Animal @b{is} @b{tagged} @b{limited} @b{record} +@example +with Interfaces.C.Strings; use Interfaces.C.Strings; +package Animals is + type Carnivore is limited interface; + pragma Convention (C_Plus_Plus, Carnivore); + function Number_Of_Teeth (X : Carnivore) + return Natural is abstract; + + type Domestic is limited interface; + pragma Convention (C_Plus_Plus, Domestic); + procedure Set_Owner + (X : in out Domestic; + Name : Chars_Ptr) is abstract; + + type Animal is tagged limited record Age : Natural; - @b{end} @b{record}; - @b{pragma} Import (C_Plus_Plus, Animal); + end record; + pragma Import (C_Plus_Plus, Animal); - @b{procedure} Set_Age (X : @b{in} @b{out} Animal; Age : Integer); - @b{pragma} Import (C_Plus_Plus, Set_Age); + procedure Set_Age (X : in out Animal; Age : Integer); + pragma Import (C_Plus_Plus, Set_Age); - @b{function} Age (X : Animal) @b{return} Integer; - @b{pragma} Import (C_Plus_Plus, Age); + function Age (X : Animal) return Integer; + pragma Import (C_Plus_Plus, Age); - @b{function} New_Animal @b{return} Animal; - @b{pragma} CPP_Constructor (New_Animal); - @b{pragma} Import (CPP, New_Animal, "_ZN6AnimalC1Ev"); + function New_Animal return Animal; + pragma CPP_Constructor (New_Animal); + pragma Import (CPP, New_Animal, "_ZN6AnimalC1Ev"); - @b{type} Dog @b{is} @b{new} Animal @b{and} Carnivore @b{and} Domestic @b{with} @b{record} + type Dog is new Animal and Carnivore and Domestic with record Tooth_Count : Natural; Owner : String (1 .. 30); - @b{end} @b{record}; - @b{pragma} Import (C_Plus_Plus, Dog); + end record; + pragma Import (C_Plus_Plus, Dog); - @b{function} Number_Of_Teeth (A : Dog) @b{return} Natural; - @b{pragma} Import (C_Plus_Plus, Number_Of_Teeth); + function Number_Of_Teeth (A : Dog) return Natural; + pragma Import (C_Plus_Plus, Number_Of_Teeth); - @b{procedure} Set_Owner (A : @b{in} @b{out} Dog; Name : Chars_Ptr); - @b{pragma} Import (C_Plus_Plus, Set_Owner); + procedure Set_Owner (A : in out Dog; Name : Chars_Ptr); + pragma Import (C_Plus_Plus, Set_Owner); - @b{function} New_Dog @b{return} Dog; - @b{pragma} CPP_Constructor (New_Dog); - @b{pragma} Import (CPP, New_Dog, "_ZN3DogC2Ev"); -@b{end} Animals; -@end smallexample + function New_Dog return Dog; + pragma CPP_Constructor (New_Dog); + pragma Import (CPP, New_Dog, "_ZN3DogC2Ev"); +end Animals; +@end example Thanks to the compatibility between GNAT run-time structures and the C++ ABI, interfacing with these C++ classes is easy. The only requirement is that all @@ -3064,9 +6425,9 @@ the primitives and components must be declared exactly in the same order in the two languages. Regarding the abstract interfaces, we must indicate to the GNAT compiler by -means of a @code{pragma Convention (C_Plus_Plus)}, the convention used to pass +means of a @cite{pragma Convention (C_Plus_Plus)}, the convention used to pass the arguments to the called primitives will be the same as for C++. For the -imported classes we use @code{pragma Import} with convention @code{C_Plus_Plus} +imported classes we use @cite{pragma Import} with convention @cite{C_Plus_Plus} to indicate that they have been defined on the C++ side; this is required because the dispatch table associated with these tagged types will be built in the C++ side and therefore will not contain the predefined Ada primitives @@ -3076,7 +6437,7 @@ As the reader can see there is no need to indicate the C++ mangled names associated with each subprogram because it is assumed that all the calls to these primitives will be dispatching calls. The only exception is the constructor, which must be registered with the compiler by means of -@code{pragma CPP_Constructor} and needs to provide its associated C++ +@cite{pragma CPP_Constructor} and needs to provide its associated C++ mangled name because the Ada compiler generates direct calls to it. With the above packages we can now declare objects of type Dog on the Ada side @@ -3086,13 +6447,13 @@ override some of its C++ primitives on the Ada side. For example, here we have a type derivation defined on the Ada side that inherits all the dispatching primitives of the ancestor from the C++ side. -@smallexample -@b{with} Animals; @b{use} Animals; -@b{package} Vaccinated_Animals @b{is} - @b{type} Vaccinated_Dog @b{is new} Dog @b{with null record}; - @b{function} Vaccination_Expired (A : Vaccinated_Dog) @b{return} Boolean; -@b{end} Vaccinated_Animals; -@end smallexample +@example +with Animals; use Animals; +package Vaccinated_Animals is + type Vaccinated_Dog is new Dog with null record; + function Vaccination_Expired (A : Vaccinated_Dog) return Boolean; +end Vaccinated_Animals; +@end example It is important to note that, because of the ABI compatibility, the programmer does not need to add any further information to indicate either the object @@ -3101,75 +6462,75 @@ layout or the dispatch table entry associated with each dispatching operation. Now let us define all the types and constructors on the Ada side and export them to C++, using the same hierarchy of our previous example: -@smallexample @c ada -@b{with} Interfaces.C.Strings; -@b{use} Interfaces.C.Strings; -@b{package} Animals @b{is} - @b{type} Carnivore @b{is} @b{limited} interface; - @b{pragma} Convention (C_Plus_Plus, Carnivore); - @b{function} Number_Of_Teeth (X : Carnivore) - @b{return} Natural @b{is} @b{abstract}; - - @b{type} Domestic @b{is} @b{limited} interface; - @b{pragma} Convention (C_Plus_Plus, Domestic); - @b{procedure} Set_Owner - (X : @b{in} @b{out} Domestic; - Name : Chars_Ptr) @b{is} @b{abstract}; - - @b{type} Animal @b{is} @b{tagged} @b{record} +@example +with Interfaces.C.Strings; +use Interfaces.C.Strings; +package Animals is + type Carnivore is limited interface; + pragma Convention (C_Plus_Plus, Carnivore); + function Number_Of_Teeth (X : Carnivore) + return Natural is abstract; + + type Domestic is limited interface; + pragma Convention (C_Plus_Plus, Domestic); + procedure Set_Owner + (X : in out Domestic; + Name : Chars_Ptr) is abstract; + + type Animal is tagged record Age : Natural; - @b{end} @b{record}; - @b{pragma} Convention (C_Plus_Plus, Animal); + end record; + pragma Convention (C_Plus_Plus, Animal); - @b{procedure} Set_Age (X : @b{in} @b{out} Animal; Age : Integer); - @b{pragma} Export (C_Plus_Plus, Set_Age); + procedure Set_Age (X : in out Animal; Age : Integer); + pragma Export (C_Plus_Plus, Set_Age); - @b{function} Age (X : Animal) @b{return} Integer; - @b{pragma} Export (C_Plus_Plus, Age); + function Age (X : Animal) return Integer; + pragma Export (C_Plus_Plus, Age); - @b{function} New_Animal @b{return} Animal'Class; - @b{pragma} Export (C_Plus_Plus, New_Animal); + function New_Animal return Animal'Class; + pragma Export (C_Plus_Plus, New_Animal); - @b{type} Dog @b{is} @b{new} Animal @b{and} Carnivore @b{and} Domestic @b{with} @b{record} + type Dog is new Animal and Carnivore and Domestic with record Tooth_Count : Natural; Owner : String (1 .. 30); - @b{end} @b{record}; - @b{pragma} Convention (C_Plus_Plus, Dog); + end record; + pragma Convention (C_Plus_Plus, Dog); - @b{function} Number_Of_Teeth (A : Dog) @b{return} Natural; - @b{pragma} Export (C_Plus_Plus, Number_Of_Teeth); + function Number_Of_Teeth (A : Dog) return Natural; + pragma Export (C_Plus_Plus, Number_Of_Teeth); - @b{procedure} Set_Owner (A : @b{in} @b{out} Dog; Name : Chars_Ptr); - @b{pragma} Export (C_Plus_Plus, Set_Owner); + procedure Set_Owner (A : in out Dog; Name : Chars_Ptr); + pragma Export (C_Plus_Plus, Set_Owner); - @b{function} New_Dog @b{return} Dog'Class; - @b{pragma} Export (C_Plus_Plus, New_Dog); -@b{end} Animals; -@end smallexample + function New_Dog return Dog'Class; + pragma Export (C_Plus_Plus, New_Dog); +end Animals; +@end example Compared with our previous example the only differences are the use of -@code{pragma Convention} (instead of @code{pragma Import}), and the use of -@code{pragma Export} to indicate to the GNAT compiler that the primitives will +@cite{pragma Convention} (instead of @cite{pragma Import}), and the use of +@cite{pragma Export} to indicate to the GNAT compiler that the primitives will be available to C++. Thanks to the ABI compatibility, on the C++ side there is nothing else to be done; as explained above, the only requirement is that all the primitives and components are declared in exactly the same order. For completeness, let us see a brief C++ main program that uses the -declarations available in @code{animals.h} (presented in our first example) to +declarations available in @cite{animals.h} (presented in our first example) to import and use the declarations from the Ada side, properly initializing and finalizing the Ada run-time system along the way: -@smallexample -@b{#include} "animals.h" -@b{#include} <iostream> -@b{using namespace} std; +@example +#include "animals.h" +#include <iostream> +using namespace std; -void Check_Carnivore (Carnivore *obj) @{@dots{}@} -void Check_Domestic (Domestic *obj) @{@dots{}@} -void Check_Animal (Animal *obj) @{@dots{}@} -void Check_Dog (Dog *obj) @{@dots{}@} +void Check_Carnivore (Carnivore *obj) @{...@} +void Check_Domestic (Domestic *obj) @{...@} +void Check_Animal (Animal *obj) @{...@} +void Check_Dog (Dog *obj) @{...@} -@b{extern} "C" @{ +extern "C" @{ void adainit (void); void adafinal (void); Dog* new_dog (); @@ -3189,16 +6550,326 @@ int main () adainit (); test(); adafinal (); return 0; @} -@end smallexample +@end example + +@node Generating Ada Bindings for C and C++ headers,,Building Mixed Ada and C++ Programs,Mixed Language Programming +@anchor{gnat_ugn/the_gnat_compilation_model id70}@anchor{c9}@anchor{gnat_ugn/the_gnat_compilation_model generating-ada-bindings-for-c-and-c-headers}@anchor{1b} +@subsection Generating Ada Bindings for C and C++ headers + + +@geindex Binding generation (for C and C++ headers) + +@geindex C headers (binding generation) + +@geindex C++ headers (binding generation) + +GNAT includes a binding generator for C and C++ headers which is +intended to do 95% of the tedious work of generating Ada specs from C +or C++ header files. + +Note that this capability is not intended to generate 100% correct Ada specs, +and will is some cases require manual adjustments, although it can often +be used out of the box in practice. + +Some of the known limitations include: + + +@itemize * + +@item +only very simple character constant macros are translated into Ada +constants. Function macros (macros with arguments) are partially translated +as comments, to be completed manually if needed. + +@item +some extensions (e.g. vector types) are not supported + +@item +pointers to pointers or complex structures are mapped to System.Address + +@item +identifiers with identical name (except casing) will generate compilation +errors (e.g. @cite{shm_get} vs @cite{SHM_GET}). +@end itemize + +The code generated is using the Ada 2005 syntax, which makes it +easier to interface with other languages than previous versions of Ada. + +@menu +* Running the binding generator:: +* Generating bindings for C++ headers:: +* Switches:: + +@end menu + +@node Running the binding generator,Generating bindings for C++ headers,,Generating Ada Bindings for C and C++ headers +@anchor{gnat_ugn/the_gnat_compilation_model id71}@anchor{ca}@anchor{gnat_ugn/the_gnat_compilation_model running-the-binding-generator}@anchor{cb} +@subsubsection Running the binding generator + + +The binding generator is part of the @emph{gcc} compiler and can be +invoked via the @emph{-fdump-ada-spec} switch, which will generate Ada +spec files for the header files specified on the command line, and all +header files needed by these files transitively. For example: + +@example +$ g++ -c -fdump-ada-spec -C /usr/include/time.h +$ gcc -c -gnat05 *.ads +@end example + +will generate, under GNU/Linux, the following files: @code{time_h.ads}, +@code{bits_time_h.ads}, @code{stddef_h.ads}, @code{bits_types_h.ads} which +correspond to the files @code{/usr/include/time.h}, +@code{/usr/include/bits/time.h}, etc..., and will then compile in Ada 2005 +mode these Ada specs. + +The @cite{-C} switch tells @emph{gcc} to extract comments from headers, +and will attempt to generate corresponding Ada comments. + +If you want to generate a single Ada file and not the transitive closure, you +can use instead the @emph{-fdump-ada-spec-slim} switch. + +You can optionally specify a parent unit, of which all generated units will +be children, using @cite{-fada-spec-parent=`@w{`}unit}. + +Note that we recommend when possible to use the @emph{g++} driver to +generate bindings, even for most C headers, since this will in general +generate better Ada specs. For generating bindings for C++ headers, it is +mandatory to use the @emph{g++} command, or @emph{gcc -x c++} which +is equivalent in this case. If @emph{g++} cannot work on your C headers +because of incompatibilities between C and C++, then you can fallback to +@emph{gcc} instead. + +For an example of better bindings generated from the C++ front-end, +the name of the parameters (when available) are actually ignored by the C +front-end. Consider the following C header: + +@example +extern void foo (int variable); +@end example + +with the C front-end, @cite{variable} is ignored, and the above is handled as: + +@example +extern void foo (int); +@end example + +generating a generic: + +@example +procedure foo (param1 : int); +@end example + +with the C++ front-end, the name is available, and we generate: + +@example +procedure foo (variable : int); +@end example + +In some cases, the generated bindings will be more complete or more meaningful +when defining some macros, which you can do via the @emph{-D} switch. This +is for example the case with @code{Xlib.h} under GNU/Linux: + +@example +$ g++ -c -fdump-ada-spec -DXLIB_ILLEGAL_ACCESS -C /usr/include/X11/Xlib.h +@end example + +The above will generate more complete bindings than a straight call without +the @emph{-DXLIB_ILLEGAL_ACCESS} switch. + +In other cases, it is not possible to parse a header file in a stand-alone +manner, because other include files need to be included first. In this +case, the solution is to create a small header file including the needed +@cite{#include} and possible @cite{#define} directives. For example, to +generate Ada bindings for @code{readline/readline.h}, you need to first +include @code{stdio.h}, so you can create a file with the following two +lines in e.g. @code{readline1.h}: + +@example +#include <stdio.h> +#include <readline/readline.h> +@end example + +and then generate Ada bindings from this file: + +@example +$ g++ -c -fdump-ada-spec readline1.h +@end example + +@node Generating bindings for C++ headers,Switches,Running the binding generator,Generating Ada Bindings for C and C++ headers +@anchor{gnat_ugn/the_gnat_compilation_model id72}@anchor{cc}@anchor{gnat_ugn/the_gnat_compilation_model generating-bindings-for-c-headers}@anchor{cd} +@subsubsection Generating bindings for C++ headers + + +Generating bindings for C++ headers is done using the same options, always +with the @emph{g++} compiler. Note that generating Ada spec from C++ headers is a +much more complex job and support for C++ headers is much more limited that +support for C headers. As a result, you will need to modify the resulting +bindings by hand more extensively when using C++ headers. + +In this mode, C++ classes will be mapped to Ada tagged types, constructors +will be mapped using the @cite{CPP_Constructor} pragma, and when possible, +multiple inheritance of abstract classes will be mapped to Ada interfaces +(see the @emph{Interfacing to C++} section in the @cite{GNAT Reference Manual} +for additional information on interfacing to C++). + +For example, given the following C++ header file: + +@example +class Carnivore @{ +public: + virtual int Number_Of_Teeth () = 0; +@}; + +class Domestic @{ +public: + virtual void Set_Owner (char* Name) = 0; +@}; + +class Animal @{ +public: + int Age_Count; + virtual void Set_Age (int New_Age); +@}; + +class Dog : Animal, Carnivore, Domestic @{ + public: + int Tooth_Count; + char *Owner; + + virtual int Number_Of_Teeth (); + virtual void Set_Owner (char* Name); + + Dog(); +@}; +@end example + +The corresponding Ada code is generated: + +@example +package Class_Carnivore is + type Carnivore is limited interface; + pragma Import (CPP, Carnivore); + + function Number_Of_Teeth (this : access Carnivore) return int is abstract; +end; +use Class_Carnivore; + +package Class_Domestic is + type Domestic is limited interface; + pragma Import (CPP, Domestic); + + procedure Set_Owner + (this : access Domestic; + Name : Interfaces.C.Strings.chars_ptr) is abstract; +end; +use Class_Domestic; + +package Class_Animal is + type Animal is tagged limited record + Age_Count : aliased int; + end record; + pragma Import (CPP, Animal); + + procedure Set_Age (this : access Animal; New_Age : int); + pragma Import (CPP, Set_Age, "_ZN6Animal7Set_AgeEi"); +end; +use Class_Animal; + +package Class_Dog is + type Dog is new Animal and Carnivore and Domestic with record + Tooth_Count : aliased int; + Owner : Interfaces.C.Strings.chars_ptr; + end record; + pragma Import (CPP, Dog); + + function Number_Of_Teeth (this : access Dog) return int; + pragma Import (CPP, Number_Of_Teeth, "_ZN3Dog15Number_Of_TeethEv"); + + procedure Set_Owner + (this : access Dog; Name : Interfaces.C.Strings.chars_ptr); + pragma Import (CPP, Set_Owner, "_ZN3Dog9Set_OwnerEPc"); + + function New_Dog return Dog; + pragma CPP_Constructor (New_Dog); + pragma Import (CPP, New_Dog, "_ZN3DogC1Ev"); +end; +use Class_Dog; +@end example + +@node Switches,,Generating bindings for C++ headers,Generating Ada Bindings for C and C++ headers +@anchor{gnat_ugn/the_gnat_compilation_model switches}@anchor{ce}@anchor{gnat_ugn/the_gnat_compilation_model switches-for-ada-binding-generation}@anchor{cf} +@subsubsection Switches + + +@geindex -fdump-ada-spec (gcc) + + +@table @asis + +@item @code{-fdump-ada-spec} + +Generate Ada spec files for the given header files transitively (including +all header files that these headers depend upon). +@end table + +@geindex -fdump-ada-spec-slim (gcc) + + +@table @asis + +@item @code{-fdump-ada-spec-slim} + +Generate Ada spec files for the header files specified on the command line +only. +@end table + +@geindex -fada-spec-parent (gcc) + + +@table @asis + +@item @code{-fada-spec-parent=@emph{unit}} + +Specifies that all files generated by @emph{-fdump-ada-spec*} are +to be child units of the specified parent unit. +@end table + +@geindex -C (gcc) + + +@table @asis + +@item @code{-C} + +Extract comments from headers and generate Ada comments in the Ada spec files. +@end table + +@node GNAT and Other Compilation Models,Using GNAT Files with External Tools,Mixed Language Programming,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model id73}@anchor{d0}@anchor{gnat_ugn/the_gnat_compilation_model gnat-and-other-compilation-models}@anchor{47} +@section GNAT and Other Compilation Models + + +This section compares the GNAT model with the approaches taken in +other environents, first the C/C++ model and then the mechanism that +has been used in other Ada systems, in particular those traditionally +used for Ada 83. + +@menu +* Comparison between GNAT and C/C++ Compilation Models:: +* Comparison between GNAT and Conventional Ada Library Models:: + +@end menu + +@node Comparison between GNAT and C/C++ Compilation Models,Comparison between GNAT and Conventional Ada Library Models,,GNAT and Other Compilation Models +@anchor{gnat_ugn/the_gnat_compilation_model comparison-between-gnat-and-c-c-compilation-models}@anchor{d1}@anchor{gnat_ugn/the_gnat_compilation_model id74}@anchor{d2} +@subsection Comparison between GNAT and C/C++ Compilation Models -@node Comparison between GNAT and C/C++ Compilation Models -@section Comparison between GNAT and C/C++ Compilation Models -@noindent The GNAT model of compilation is close to the C and C++ models. You can think of Ada specs as corresponding to header files in C. As in C, you don't need to compile specs; they are compiled when they are used. The -Ada @code{with} is similar in effect to the @code{#include} of a C +Ada @emph{with} is similar in effect to the @cite{#include} of a C header. One notable difference is that, in Ada, you may compile specs separately @@ -3214,25 +6885,28 @@ example. The binder satisfies the Ada requirement that it be impossible to construct an inconsistent program when the compiler is used in normal mode. -@cindex Elaboration order control +@geindex Elaboration order control + The other important function of the binder is to deal with elaboration issues. There are also elaboration issues in C++ that are handled automatically. This automatic handling has the advantage of being simpler to use, but the C++ programmer has no control over elaboration. -Where @code{gnatbind} might complain there was no valid order of +Where @cite{gnatbind} might complain there was no valid order of elaboration, a C++ compiler would simply construct a program that malfunctioned at run time. -@node Comparison between GNAT and Conventional Ada Library Models -@section Comparison between GNAT and Conventional Ada Library Models +@node Comparison between GNAT and Conventional Ada Library Models,,Comparison between GNAT and C/C++ Compilation Models,GNAT and Other Compilation Models +@anchor{gnat_ugn/the_gnat_compilation_model comparison-between-gnat-and-conventional-ada-library-models}@anchor{d3}@anchor{gnat_ugn/the_gnat_compilation_model id75}@anchor{d4} +@subsection Comparison between GNAT and Conventional Ada Library Models + -@noindent This section is intended for Ada programmers who have used an Ada compiler implementing the traditional Ada library model, as described in the Ada Reference Manual. -@cindex GNAT library -In GNAT, there is no ``library'' in the normal sense. Instead, the set of +@geindex GNAT library + +In GNAT, there is no 'library' in the normal sense. Instead, the set of source files themselves acts as the library. Compiling Ada programs does not generate any centralized information, but rather an object file and a ALI file, which are of interest only to the binder and linker. @@ -3241,43 +6915,46 @@ the source file being compiled, but also from the centralized library. This means that the effect of a compilation depends on what has been previously compiled. In particular: -@itemize @bullet -@item -When a unit is @code{with}'ed, the unit seen by the compiler corresponds + +@itemize * + +@item +When a unit is @emph{with}ed, the unit seen by the compiler corresponds to the version of the unit most recently compiled into the library. -@item +@item Inlining is effective only if the necessary body has already been compiled into the library. -@item +@item Compiling a unit may obsolete other units in the library. @end itemize -@noindent In GNAT, compiling one unit never affects the compilation of any other units because the compiler reads only source files. Only changes to source files can affect the results of a compilation. In particular: -@itemize @bullet -@item -When a unit is @code{with}'ed, the unit seen by the compiler corresponds + +@itemize * + +@item +When a unit is @emph{with}ed, the unit seen by the compiler corresponds to the source version of the unit that is currently accessible to the compiler. -@item -@cindex Inlining +@geindex Inlining + +@item Inlining requires the appropriate source files for the package or subprogram bodies to be available to the compiler. Inlining is always -effective, independent of the order in which units are complied. +effective, independent of the order in which units are compiled. -@item +@item Compiling a unit never affects any other compilations. The editing of sources may cause previous compilations to be out of date if they depended on the source file being modified. @end itemize -@noindent The most important result of these differences is that order of compilation is never significant in GNAT. There is no situation in which one is required to do one compilation before another. What shows up as order of @@ -3286,144 +6963,1571 @@ GNAT, simple source dependencies; in other words, there is only a set of rules saying what source files must be present when a file is compiled. +@node Using GNAT Files with External Tools,,GNAT and Other Compilation Models,The GNAT Compilation Model +@anchor{gnat_ugn/the_gnat_compilation_model using-gnat-files-with-external-tools}@anchor{1c}@anchor{gnat_ugn/the_gnat_compilation_model id76}@anchor{d5} +@section Using GNAT Files with External Tools + + +This section explains how files that are produced by GNAT may be +used with tools designed for other languages. + +@menu +* Using Other Utility Programs with GNAT:: +* The External Symbol Naming Scheme of GNAT:: + +@end menu + +@node Using Other Utility Programs with GNAT,The External Symbol Naming Scheme of GNAT,,Using GNAT Files with External Tools +@anchor{gnat_ugn/the_gnat_compilation_model using-other-utility-programs-with-gnat}@anchor{d6}@anchor{gnat_ugn/the_gnat_compilation_model id77}@anchor{d7} +@subsection Using Other Utility Programs with GNAT + + +The object files generated by GNAT are in standard system format and in +particular the debugging information uses this format. This means +programs generated by GNAT can be used with existing utilities that +depend on these formats. + +In general, any utility program that works with C will also often work with +Ada programs generated by GNAT. This includes software utilities such as +gprof (a profiling program), gdb (the FSF debugger), and utilities such +as Purify. + +@node The External Symbol Naming Scheme of GNAT,,Using Other Utility Programs with GNAT,Using GNAT Files with External Tools +@anchor{gnat_ugn/the_gnat_compilation_model the-external-symbol-naming-scheme-of-gnat}@anchor{d8}@anchor{gnat_ugn/the_gnat_compilation_model id78}@anchor{d9} +@subsection The External Symbol Naming Scheme of GNAT + + +In order to interpret the output from GNAT, when using tools that are +originally intended for use with other languages, it is useful to +understand the conventions used to generate link names from the Ada +entity names. + +All link names are in all lowercase letters. With the exception of library +procedure names, the mechanism used is simply to use the full expanded +Ada name with dots replaced by double underscores. For example, suppose +we have the following package spec: + +@example +package QRS is + MN : Integer; +end QRS; +@end example + +@geindex pragma Export + +The variable @cite{MN} has a full expanded Ada name of @cite{QRS.MN}, so +the corresponding link name is @cite{qrs__mn}. +Of course if a @cite{pragma Export} is used this may be overridden: + +@example +package Exports is + Var1 : Integer; + pragma Export (Var1, C, External_Name => "var1_name"); + Var2 : Integer; + pragma Export (Var2, C, Link_Name => "var2_link_name"); +end Exports; +@end example + +In this case, the link name for @cite{Var1} is whatever link name the +C compiler would assign for the C function @cite{var1_name}. This typically +would be either @cite{var1_name} or @cite{_var1_name}, depending on operating +system conventions, but other possibilities exist. The link name for +@cite{Var2} is @cite{var2_link_name}, and this is not operating system +dependent. + +One exception occurs for library level procedures. A potential ambiguity +arises between the required name @cite{_main} for the C main program, +and the name we would otherwise assign to an Ada library level procedure +called @cite{Main} (which might well not be the main program). + +To avoid this ambiguity, we attach the prefix @cite{_ada_} to such +names. So if we have a library level procedure such as: + +@example +procedure Hello (S : String); +@end example + +the external name of this procedure will be @cite{_ada_hello}. + +@c -- Example: A |withing| unit has a |with| clause, it |withs| a |withed| unit + +@node Building Executable Programs with GNAT,GNAT Project Manager,The GNAT Compilation Model,Top +@anchor{gnat_ugn/building_executable_programs_with_gnat building-executable-programs-with-gnat}@anchor{a}@anchor{gnat_ugn/building_executable_programs_with_gnat doc}@anchor{da}@anchor{gnat_ugn/building_executable_programs_with_gnat id1}@anchor{db} +@chapter Building Executable Programs with GNAT + + +This chapter describes first the gnatmake tool +(@ref{1d,,Building with gnatmake}), +which automatically determines the set of sources +needed by an Ada compilation unit and executes the necessary +(re)compilations, binding and linking. +It also explains how to use each tool individually: the +compiler (gcc, see @ref{1e,,Compiling with gcc}), +binder (gnatbind, see @ref{1f,,Binding with gnatbind}), +and linker (gnatlink, see @ref{20,,Linking with gnatlink}) +to build executable programs. +Finally, this chapter provides examples of +how to make use of the general GNU make mechanism +in a GNAT context (see @ref{21,,Using the GNU make Utility}). + +@menu +* Building with gnatmake:: +* Compiling with gcc:: +* Compiler Switches:: +* Binding with gnatbind:: +* Linking with gnatlink:: +* Using the GNU make Utility:: + +@end menu + +@node Building with gnatmake,Compiling with gcc,,Building Executable Programs with GNAT +@anchor{gnat_ugn/building_executable_programs_with_gnat the-gnat-make-program-gnatmake}@anchor{1d}@anchor{gnat_ugn/building_executable_programs_with_gnat building-with-gnatmake}@anchor{dc} +@section Building with @emph{gnatmake} + + +@geindex gnatmake + +A typical development cycle when working on an Ada program consists of +the following steps: + + +@enumerate + +@item +Edit some sources to fix bugs; + +@item +Add enhancements; + +@item +Compile all sources affected; + +@item +Rebind and relink; and + +@item +Test. +@end enumerate + +@geindex Dependency rules (compilation) + +The third step in particular can be tricky, because not only do the modified +files have to be compiled, but any files depending on these files must also be +recompiled. The dependency rules in Ada can be quite complex, especially +in the presence of overloading, @cite{use} clauses, generics and inlined +subprograms. + +@emph{gnatmake} automatically takes care of the third and fourth steps +of this process. It determines which sources need to be compiled, +compiles them, and binds and links the resulting object files. + +Unlike some other Ada make programs, the dependencies are always +accurately recomputed from the new sources. The source based approach of +the GNAT compilation model makes this possible. This means that if +changes to the source program cause corresponding changes in +dependencies, they will always be tracked exactly correctly by +@emph{gnatmake}. + +Note that for advanced description of project structure, we recommend creating +a project file as explained in @ref{b,,GNAT Project Manager} and use the +@emph{gprbuild} tool which supports building with project files and works similarly +to @emph{gnatmake}. + +@menu +* Running gnatmake:: +* Switches for gnatmake:: +* Mode Switches for gnatmake:: +* Notes on the Command Line:: +* How gnatmake Works:: +* Examples of gnatmake Usage:: + +@end menu + +@node Running gnatmake,Switches for gnatmake,,Building with gnatmake +@anchor{gnat_ugn/building_executable_programs_with_gnat running-gnatmake}@anchor{dd}@anchor{gnat_ugn/building_executable_programs_with_gnat id2}@anchor{de} +@subsection Running @emph{gnatmake} + + +The usual form of the @emph{gnatmake} command is + +@example +$ gnatmake [<switches>] <file_name> [<file_names>] [<mode_switches>] +@end example + +The only required argument is one @cite{file_name}, which specifies +a compilation unit that is a main program. Several @cite{file_names} can be +specified: this will result in several executables being built. +If @cite{switches} are present, they can be placed before the first +@cite{file_name}, between @cite{file_names} or after the last @cite{file_name}. +If @cite{mode_switches} are present, they must always be placed after +the last @cite{file_name} and all @cite{switches}. + +If you are using standard file extensions (@code{.adb} and +@code{.ads}), then the +extension may be omitted from the @cite{file_name} arguments. However, if +you are using non-standard extensions, then it is required that the +extension be given. A relative or absolute directory path can be +specified in a @cite{file_name}, in which case, the input source file will +be searched for in the specified directory only. Otherwise, the input +source file will first be searched in the directory where +@emph{gnatmake} was invoked and if it is not found, it will be search on +the source path of the compiler as described in +@ref{8e,,Search Paths and the Run-Time Library (RTL)}. + +All @emph{gnatmake} output (except when you specify @emph{-M}) is sent to +@code{stderr}. The output produced by the +@emph{-M} switch is sent to @code{stdout}. + +@node Switches for gnatmake,Mode Switches for gnatmake,Running gnatmake,Building with gnatmake +@anchor{gnat_ugn/building_executable_programs_with_gnat switches-for-gnatmake}@anchor{df}@anchor{gnat_ugn/building_executable_programs_with_gnat id3}@anchor{e0} +@subsection Switches for @emph{gnatmake} + + +You may specify any of the following switches to @emph{gnatmake}: + +@geindex --version (gnatmake) + + +@table @asis + +@item @code{--version} + +Display Copyright and version, then exit disregarding all other options. +@end table + +@geindex --help (gnatmake) + + +@table @asis + +@item @code{--help} + +If @code{--version} was not used, display usage, then exit disregarding +all other options. +@end table + +@geindex --GCC=compiler_name (gnatmake) + + +@table @asis + +@item @code{--GCC=@emph{compiler_name}} + +Program used for compiling. The default is @code{gcc}. You need to use +quotes around @cite{compiler_name} if @cite{compiler_name} contains +spaces or other separator characters. +As an example @code{--GCC="foo -x -y"} +will instruct @emph{gnatmake} to use @code{foo -x -y} as your +compiler. A limitation of this syntax is that the name and path name of +the executable itself must not include any embedded spaces. Note that +switch @code{-c} is always inserted after your command name. Thus in the +above example the compiler command that will be used by @emph{gnatmake} +will be @code{foo -c -x -y}. If several @code{--GCC=compiler_name} are +used, only the last @cite{compiler_name} is taken into account. However, +all the additional switches are also taken into account. Thus, +@code{--GCC="foo -x -y" --GCC="bar -z -t"} is equivalent to +@code{--GCC="bar -x -y -z -t"}. +@end table + +@geindex --GNATBIND=binder_name (gnatmake) + + +@table @asis + +@item @code{--GNATBIND=@emph{binder_name}} + +Program used for binding. The default is @code{gnatbind}. You need to +use quotes around @cite{binder_name} if @cite{binder_name} contains spaces +or other separator characters. +As an example @code{--GNATBIND="bar -x -y"} +will instruct @emph{gnatmake} to use @cite{bar -x -y} as your +binder. Binder switches that are normally appended by @emph{gnatmake} +to @code{gnatbind} are now appended to the end of @cite{bar -x -y}. +A limitation of this syntax is that the name and path name of the executable +itself must not include any embedded spaces. +@end table + +@geindex --GNATLINK=linker_name (gnatmake) + + +@table @asis + +@item @code{--GNATLINK=@emph{linker_name}} + +Program used for linking. The default is @code{gnatlink}. You need to +use quotes around @cite{linker_name} if @cite{linker_name} contains spaces +or other separator characters. +As an example @code{--GNATLINK="lan -x -y"} +will instruct @emph{gnatmake} to use @code{lan -x -y} as your +linker. Linker switches that are normally appended by @code{gnatmake} to +@code{gnatlink} are now appended to the end of @code{lan -x -y}. +A limitation of this syntax is that the name and path name of the executable +itself must not include any embedded spaces. + +@item @code{--create-map-file} + +When linking an executable, create a map file. The name of the map file +has the same name as the executable with extension ".map". + +@item @code{--create-map-file=@emph{mapfile}} + +When linking an executable, create a map file with the specified name. +@end table + +@geindex --create-missing-dirs (gnatmake) + + +@table @asis + +@item @code{--create-missing-dirs} + +When using project files (@code{-P@emph{project}}), automatically create +missing object directories, library directories and exec +directories. + +@item @code{--single-compile-per-obj-dir} + +Disallow simultaneous compilations in the same object directory when +project files are used. + +@item @code{--subdirs=@emph{subdir}} + +Actual object directory of each project file is the subdirectory subdir of the +object directory specified or defaulted in the project file. + +@item @code{--unchecked-shared-lib-imports} + +By default, shared library projects are not allowed to import static library +projects. When this switch is used on the command line, this restriction is +relaxed. + +@item @code{--source-info=@emph{source info file}} + +Specify a source info file. This switch is active only when project files +are used. If the source info file is specified as a relative path, then it is +relative to the object directory of the main project. If the source info file +does not exist, then after the Project Manager has successfully parsed and +processed the project files and found the sources, it creates the source info +file. If the source info file already exists and can be read successfully, +then the Project Manager will get all the needed information about the sources +from the source info file and will not look for them. This reduces the time +to process the project files, especially when looking for sources that take a +long time. If the source info file exists but cannot be parsed successfully, +the Project Manager will attempt to recreate it. If the Project Manager fails +to create the source info file, a message is issued, but gnatmake does not +fail. @emph{gnatmake} "trusts" the source info file. This means that +if the source files have changed (addition, deletion, moving to a different +source directory), then the source info file need to be deleted and recreated. +@end table + +@geindex -a (gnatmake) + + +@table @asis + +@item @code{-a} + +Consider all files in the make process, even the GNAT internal system +files (for example, the predefined Ada library files), as well as any +locked files. Locked files are files whose ALI file is write-protected. +By default, +@emph{gnatmake} does not check these files, +because the assumption is that the GNAT internal files are properly up +to date, and also that any write protected ALI files have been properly +installed. Note that if there is an installation problem, such that one +of these files is not up to date, it will be properly caught by the +binder. +You may have to specify this switch if you are working on GNAT +itself. The switch @code{-a} is also useful +in conjunction with @code{-f} +if you need to recompile an entire application, +including run-time files, using special configuration pragmas, +such as a @cite{Normalize_Scalars} pragma. + +By default +@code{gnatmake -a} compiles all GNAT +internal files with +@code{gcc -c -gnatpg} rather than @code{gcc -c}. +@end table + +@geindex -b (gnatmake) + + +@table @asis + +@item @code{-b} + +Bind only. Can be combined with @emph{-c} to do +compilation and binding, but no link. +Can be combined with @emph{-l} +to do binding and linking. When not combined with +@emph{-c} +all the units in the closure of the main program must have been previously +compiled and must be up to date. The root unit specified by @cite{file_name} +may be given without extension, with the source extension or, if no GNAT +Project File is specified, with the ALI file extension. +@end table + +@geindex -c (gnatmake) + + +@table @asis + +@item @code{-c} + +Compile only. Do not perform binding, except when @emph{-b} +is also specified. Do not perform linking, except if both +@emph{-b} and +@emph{-l} are also specified. +If the root unit specified by @cite{file_name} is not a main unit, this is the +default. Otherwise @emph{gnatmake} will attempt binding and linking +unless all objects are up to date and the executable is more recent than +the objects. +@end table + +@geindex -C (gnatmake) + + +@table @asis + +@item @code{-C} + +Use a temporary mapping file. A mapping file is a way to communicate +to the compiler two mappings: from unit names to file names (without +any directory information) and from file names to path names (with +full directory information). A mapping file can make the compiler's +file searches faster, especially if there are many source directories, +or the sources are read over a slow network connection. If +@emph{-P} is used, a mapping file is always used, so +@emph{-C} is unnecessary; in this case the mapping file +is initially populated based on the project file. If +@emph{-C} is used without +@emph{-P}, +the mapping file is initially empty. Each invocation of the compiler +will add any newly accessed sources to the mapping file. +@end table + +@geindex -C= (gnatmake) + + +@table @asis + +@item @code{-C=@emph{file}} + +Use a specific mapping file. The file, specified as a path name (absolute or +relative) by this switch, should already exist, otherwise the switch is +ineffective. The specified mapping file will be communicated to the compiler. +This switch is not compatible with a project file +(-P`file`) or with multiple compiling processes +(-jnnn, when nnn is greater than 1). +@end table + +@geindex -d (gnatmake) + + +@table @asis + +@item @code{-d} + +Display progress for each source, up to date or not, as a single line: + +@example +completed x out of y (zz%) +@end example + +If the file needs to be compiled this is displayed after the invocation of +the compiler. These lines are displayed even in quiet output mode. +@end table + +@geindex -D (gnatmake) + + +@table @asis + +@item @code{-D @emph{dir}} + +Put all object files and ALI file in directory @cite{dir}. +If the @emph{-D} switch is not used, all object files +and ALI files go in the current working directory. + +This switch cannot be used when using a project file. +@end table + +@geindex -eI (gnatmake) + + +@table @asis + +@item @code{-eI@emph{nnn}} + +Indicates that the main source is a multi-unit source and the rank of the unit +in the source file is nnn. nnn needs to be a positive number and a valid +index in the source. This switch cannot be used when @emph{gnatmake} is +invoked for several mains. +@end table + +@geindex -eL (gnatmake) + +@geindex symbolic links + + +@table @asis + +@item @code{-eL} + +Follow all symbolic links when processing project files. +This should be used if your project uses symbolic links for files or +directories, but is not needed in other cases. + +@geindex naming scheme + +This also assumes that no directory matches the naming scheme for files (for +instance that you do not have a directory called "sources.ads" when using the +default GNAT naming scheme). + +When you do not have to use this switch (i.e., by default), gnatmake is able to +save a lot of system calls (several per source file and object file), which +can result in a significant speed up to load and manipulate a project file, +especially when using source files from a remote system. +@end table + +@geindex -eS (gnatmake) + + +@table @asis + +@item @code{-eS} + +Output the commands for the compiler, the binder and the linker +on standard output, +instead of standard error. +@end table + +@geindex -f (gnatmake) + + +@table @asis + +@item @code{-f} + +Force recompilations. Recompile all sources, even though some object +files may be up to date, but don't recompile predefined or GNAT internal +files or locked files (files with a write-protected ALI file), +unless the @emph{-a} switch is also specified. +@end table + +@geindex -F (gnatmake) + + +@table @asis + +@item @code{-F} + +When using project files, if some errors or warnings are detected during +parsing and verbose mode is not in effect (no use of switch +-v), then error lines start with the full path name of the project +file, rather than its simple file name. +@end table + +@geindex -g (gnatmake) + + +@table @asis + +@item @code{-g} + +Enable debugging. This switch is simply passed to the compiler and to the +linker. +@end table + +@geindex -i (gnatmake) + + +@table @asis + +@item @code{-i} + +In normal mode, @emph{gnatmake} compiles all object files and ALI files +into the current directory. If the @emph{-i} switch is used, +then instead object files and ALI files that already exist are overwritten +in place. This means that once a large project is organized into separate +directories in the desired manner, then @emph{gnatmake} will automatically +maintain and update this organization. If no ALI files are found on the +Ada object path (see @ref{8e,,Search Paths and the Run-Time Library (RTL)}), +the new object and ALI files are created in the +directory containing the source being compiled. If another organization +is desired, where objects and sources are kept in different directories, +a useful technique is to create dummy ALI files in the desired directories. +When detecting such a dummy file, @emph{gnatmake} will be forced to +recompile the corresponding source file, and it will be put the resulting +object and ALI files in the directory where it found the dummy file. +@end table + +@geindex -j (gnatmake) + +@geindex Parallel make + + +@table @asis + +@item @code{-j@emph{n}} + +Use @cite{n} processes to carry out the (re)compilations. On a multiprocessor +machine compilations will occur in parallel. If @cite{n} is 0, then the +maximum number of parallel compilations is the number of core processors +on the platform. In the event of compilation errors, messages from various +compilations might get interspersed (but @emph{gnatmake} will give you the +full ordered list of failing compiles at the end). If this is problematic, +rerun the make process with n set to 1 to get a clean list of messages. +@end table + +@geindex -k (gnatmake) + + +@table @asis + +@item @code{-k} + +Keep going. Continue as much as possible after a compilation error. To +ease the programmer's task in case of compilation errors, the list of +sources for which the compile fails is given when @emph{gnatmake} +terminates. + +If @emph{gnatmake} is invoked with several @code{file_names} and with this +switch, if there are compilation errors when building an executable, +@emph{gnatmake} will not attempt to build the following executables. +@end table + +@geindex -l (gnatmake) + + +@table @asis + +@item @code{-l} + +Link only. Can be combined with @emph{-b} to binding +and linking. Linking will not be performed if combined with +@emph{-c} +but not with @emph{-b}. +When not combined with @emph{-b} +all the units in the closure of the main program must have been previously +compiled and must be up to date, and the main program needs to have been bound. +The root unit specified by @cite{file_name} +may be given without extension, with the source extension or, if no GNAT +Project File is specified, with the ALI file extension. +@end table + +@geindex -m (gnatmake) + + +@table @asis + +@item @code{-m} + +Specify that the minimum necessary amount of recompilations +be performed. In this mode @emph{gnatmake} ignores time +stamp differences when the only +modifications to a source file consist in adding/removing comments, +empty lines, spaces or tabs. This means that if you have changed the +comments in a source file or have simply reformatted it, using this +switch will tell @emph{gnatmake} not to recompile files that depend on it +(provided other sources on which these files depend have undergone no +semantic modifications). Note that the debugging information may be +out of date with respect to the sources if the @emph{-m} switch causes +a compilation to be switched, so the use of this switch represents a +trade-off between compilation time and accurate debugging information. +@end table + +@geindex Dependencies +@geindex producing list + +@geindex -M (gnatmake) + + +@table @asis + +@item @code{-M} + +Check if all objects are up to date. If they are, output the object +dependences to @code{stdout} in a form that can be directly exploited in +a @code{Makefile}. By default, each source file is prefixed with its +(relative or absolute) directory name. This name is whatever you +specified in the various @emph{-aI} +and @emph{-I} switches. If you use +@cite{gnatmake -M} @emph{-q} +(see below), only the source file names, +without relative paths, are output. If you just specify the @emph{-M} +switch, dependencies of the GNAT internal system files are omitted. This +is typically what you want. If you also specify +the @emph{-a} switch, +dependencies of the GNAT internal files are also listed. Note that +dependencies of the objects in external Ada libraries (see +switch @code{-aL@emph{dir}} in the following list) +are never reported. +@end table + +@geindex -n (gnatmake) + + +@table @asis + +@item @code{-n} + +Don't compile, bind, or link. Checks if all objects are up to date. +If they are not, the full name of the first file that needs to be +recompiled is printed. +Repeated use of this option, followed by compiling the indicated source +file, will eventually result in recompiling all required units. +@end table + +@geindex -o (gnatmake) + + +@table @asis + +@item @code{-o @emph{exec_name}} + +Output executable name. The name of the final executable program will be +@cite{exec_name}. If the @emph{-o} switch is omitted the default +name for the executable will be the name of the input file in appropriate form +for an executable file on the host system. + +This switch cannot be used when invoking @emph{gnatmake} with several +@code{file_names}. +@end table + +@geindex -p (gnatmake) + + +@table @asis + +@item @code{-p} + +Same as @code{--create-missing-dirs} +@end table + +@geindex -P (gnatmake) + + +@table @asis + +@item @code{-P@emph{project}} + +Use project file @cite{project}. Only one such switch can be used. +@ref{e1,,gnatmake and Project Files}. +@end table + +@geindex -q (gnatmake) + + +@table @asis + +@item @code{-q} + +Quiet. When this flag is not set, the commands carried out by +@emph{gnatmake} are displayed. +@end table + +@geindex -s (gnatmake) + + +@table @asis + +@item @code{-s} + +Recompile if compiler switches have changed since last compilation. +All compiler switches but -I and -o are taken into account in the +following way: +orders between different 'first letter' switches are ignored, but +orders between same switches are taken into account. For example, +@emph{-O -O2} is different than @emph{-O2 -O}, but @emph{-g -O} +is equivalent to @emph{-O -g}. + +This switch is recommended when Integrated Preprocessing is used. +@end table + +@geindex -u (gnatmake) + + +@table @asis + +@item @code{-u} + +Unique. Recompile at most the main files. It implies -c. Combined with +-f, it is equivalent to calling the compiler directly. Note that using +-u with a project file and no main has a special meaning +(@ref{e2,,Project Files and Main Subprograms}). +@end table + +@geindex -U (gnatmake) + + +@table @asis + +@item @code{-U} + +When used without a project file or with one or several mains on the command +line, is equivalent to -u. When used with a project file and no main +on the command line, all sources of all project files are checked and compiled +if not up to date, and libraries are rebuilt, if necessary. +@end table + +@geindex -v (gnatmake) + + +@table @asis + +@item @code{-v} + +Verbose. Display the reason for all recompilations @emph{gnatmake} +decides are necessary, with the highest verbosity level. +@end table + +@geindex -vl (gnatmake) + + +@table @asis + +@item @code{-vl} + +Verbosity level Low. Display fewer lines than in verbosity Medium. +@end table + +@geindex -vm (gnatmake) + + +@table @asis + +@item @code{-vm} + +Verbosity level Medium. Potentially display fewer lines than in verbosity High. +@end table + +@geindex -vm (gnatmake) + + +@table @asis + +@item @code{-vh} + +Verbosity level High. Equivalent to -v. + +@item @code{-vP@emph{x}} + +Indicate the verbosity of the parsing of GNAT project files. +See @ref{e3,,Switches Related to Project Files}. +@end table + +@geindex -x (gnatmake) + + +@table @asis + +@item @code{-x} + +Indicate that sources that are not part of any Project File may be compiled. +Normally, when using Project Files, only sources that are part of a Project +File may be compile. When this switch is used, a source outside of all Project +Files may be compiled. The ALI file and the object file will be put in the +object directory of the main Project. The compilation switches used will only +be those specified on the command line. Even when +@emph{-x} is used, mains specified on the +command line need to be sources of a project file. + +@item @code{-X@emph{name}=@emph{value}} + +Indicate that external variable @cite{name} has the value @cite{value}. +The Project Manager will use this value for occurrences of +@cite{external(name)} when parsing the project file. +@ref{e3,,Switches Related to Project Files}. +@end table -@c ************************* -@node Compiling with gcc -@chapter Compiling with @command{gcc} +@geindex -z (gnatmake) + + +@table @asis + +@item @code{-z} + +No main subprogram. Bind and link the program even if the unit name +given on the command line is a package name. The resulting executable +will execute the elaboration routines of the package and its closure, +then the finalization routines. +@end table + +@subsubheading GCC switches + + +Any uppercase or multi-character switch that is not a @emph{gnatmake} switch +is passed to @emph{gcc} (e.g., @emph{-O}, @emph{-gnato,} etc.) + +@subsubheading Source and library search path switches + + +@geindex -aI (gnatmake) + + +@table @asis + +@item @code{-aI@emph{dir}} + +When looking for source files also look in directory @cite{dir}. +The order in which source files search is undertaken is +described in @ref{8e,,Search Paths and the Run-Time Library (RTL)}. +@end table + +@geindex -aL (gnatmake) + + +@table @asis + +@item @code{-aL@emph{dir}} + +Consider @cite{dir} as being an externally provided Ada library. +Instructs @emph{gnatmake} to skip compilation units whose @code{.ALI} +files have been located in directory @cite{dir}. This allows you to have +missing bodies for the units in @cite{dir} and to ignore out of date bodies +for the same units. You still need to specify +the location of the specs for these units by using the switches +@code{-aI@emph{dir}} or @code{-I@emph{dir}}. +Note: this switch is provided for compatibility with previous versions +of @emph{gnatmake}. The easier method of causing standard libraries +to be excluded from consideration is to write-protect the corresponding +ALI files. +@end table + +@geindex -aO (gnatmake) + + +@table @asis + +@item @code{-aO@emph{dir}} + +When searching for library and object files, look in directory +@cite{dir}. The order in which library files are searched is described in +@ref{91,,Search Paths for gnatbind}. +@end table + +@geindex Search paths +@geindex for gnatmake + +@geindex -A (gnatmake) + + +@table @asis + +@item @code{-A@emph{dir}} + +Equivalent to @code{-aL@emph{dir}} @code{-aI@emph{dir}}. + +@geindex -I (gnatmake) + +@item @code{-I@emph{dir}} + +Equivalent to @code{-aO@emph{dir} -aI@emph{dir}}. +@end table + +@geindex -I- (gnatmake) + +@geindex Source files +@geindex suppressing search + + +@table @asis + +@item @code{-I-} + +Do not look for source files in the directory containing the source +file named in the command line. +Do not look for ALI or object files in the directory +where @emph{gnatmake} was invoked. +@end table + +@geindex -L (gnatmake) + +@geindex Linker libraries + + +@table @asis + +@item @code{-L@emph{dir}} + +Add directory @cite{dir} to the list of directories in which the linker +will search for libraries. This is equivalent to +@code{-largs} @code{-L@emph{dir}}. +Furthermore, under Windows, the sources pointed to by the libraries path +set in the registry are not searched for. +@end table + +@geindex -nostdinc (gnatmake) + + +@table @asis + +@item @code{-nostdinc} + +Do not look for source files in the system default directory. +@end table + +@geindex -nostdlib (gnatmake) + + +@table @asis + +@item @code{-nostdlib} + +Do not look for library files in the system default directory. +@end table + +@geindex --RTS (gnatmake) + + +@table @asis -@noindent -This chapter discusses how to compile Ada programs using the @command{gcc} +@item @code{--RTS=@emph{rts-path}} + +Specifies the default location of the runtime library. GNAT looks for the +runtime +in the following directories, and stops as soon as a valid runtime is found +(@code{adainclude} or @code{ada_source_path}, and @code{adalib} or +@code{ada_object_path} present): + + +@itemize * + +@item +@emph{<current directory>/$rts_path} + +@item +@emph{<default-search-dir>/$rts_path} + +@item +@emph{<default-search-dir>/rts-$rts_path} + +@item +The selected path is handled like a normal RTS path. +@end itemize +@end table + +@node Mode Switches for gnatmake,Notes on the Command Line,Switches for gnatmake,Building with gnatmake +@anchor{gnat_ugn/building_executable_programs_with_gnat id4}@anchor{e4}@anchor{gnat_ugn/building_executable_programs_with_gnat mode-switches-for-gnatmake}@anchor{e5} +@subsection Mode Switches for @emph{gnatmake} + + +The mode switches (referred to as @cite{mode_switches}) allow the +inclusion of switches that are to be passed to the compiler itself, the +binder or the linker. The effect of a mode switch is to cause all +subsequent switches up to the end of the switch list, or up to the next +mode switch, to be interpreted as switches to be passed on to the +designated component of GNAT. + +@geindex -cargs (gnatmake) + + +@table @asis + +@item @code{-cargs @emph{switches}} + +Compiler switches. Here @cite{switches} is a list of switches +that are valid switches for @emph{gcc}. They will be passed on to +all compile steps performed by @emph{gnatmake}. +@end table + +@geindex -bargs (gnatmake) + + +@table @asis + +@item @code{-bargs @emph{switches}} + +Binder switches. Here @cite{switches} is a list of switches +that are valid switches for @cite{gnatbind}. They will be passed on to +all bind steps performed by @emph{gnatmake}. +@end table + +@geindex -largs (gnatmake) + + +@table @asis + +@item @code{-largs @emph{switches}} + +Linker switches. Here @cite{switches} is a list of switches +that are valid switches for @emph{gnatlink}. They will be passed on to +all link steps performed by @emph{gnatmake}. +@end table + +@geindex -margs (gnatmake) + + +@table @asis + +@item @code{-margs @emph{switches}} + +Make switches. The switches are directly interpreted by @emph{gnatmake}, +regardless of any previous occurrence of @emph{-cargs}, @emph{-bargs} +or @emph{-largs}. +@end table + +@node Notes on the Command Line,How gnatmake Works,Mode Switches for gnatmake,Building with gnatmake +@anchor{gnat_ugn/building_executable_programs_with_gnat id5}@anchor{e6}@anchor{gnat_ugn/building_executable_programs_with_gnat notes-on-the-command-line}@anchor{e7} +@subsection Notes on the Command Line + + +This section contains some additional useful notes on the operation +of the @emph{gnatmake} command. + +@geindex Recompilation (by gnatmake) + + +@itemize * + +@item +If @emph{gnatmake} finds no ALI files, it recompiles the main program +and all other units required by the main program. +This means that @emph{gnatmake} +can be used for the initial compile, as well as during subsequent steps of +the development cycle. + +@item +If you enter @code{gnatmake foo.adb}, where @code{foo} +is a subunit or body of a generic unit, @emph{gnatmake} recompiles +@code{foo.adb} (because it finds no ALI) and stops, issuing a +warning. + +@item +In @emph{gnatmake} the switch @emph{-I} +is used to specify both source and +library file paths. Use @emph{-aI} +instead if you just want to specify +source paths only and @emph{-aO} +if you want to specify library paths +only. + +@item +@emph{gnatmake} will ignore any files whose ALI file is write-protected. +This may conveniently be used to exclude standard libraries from +consideration and in particular it means that the use of the +@emph{-f} switch will not recompile these files +unless @emph{-a} is also specified. + +@item +@emph{gnatmake} has been designed to make the use of Ada libraries +particularly convenient. Assume you have an Ada library organized +as follows: @emph{obj-dir} contains the objects and ALI files for +of your Ada compilation units, +whereas @emph{include-dir} contains the +specs of these units, but no bodies. Then to compile a unit +stored in @cite{main.adb}, which uses this Ada library you would just type: + +@example +$ gnatmake -aI`include-dir` -aL`obj-dir` main +@end example + +@item +Using @emph{gnatmake} along with the @emph{-m (minimal recompilation)} +switch provides a mechanism for avoiding unnecessary recompilations. Using +this switch, +you can update the comments/format of your +source files without having to recompile everything. Note, however, that +adding or deleting lines in a source files may render its debugging +info obsolete. If the file in question is a spec, the impact is rather +limited, as that debugging info will only be useful during the +elaboration phase of your program. For bodies the impact can be more +significant. In all events, your debugger will warn you if a source file +is more recent than the corresponding object, and alert you to the fact +that the debugging information may be out of date. +@end itemize + +@node How gnatmake Works,Examples of gnatmake Usage,Notes on the Command Line,Building with gnatmake +@anchor{gnat_ugn/building_executable_programs_with_gnat id6}@anchor{e8}@anchor{gnat_ugn/building_executable_programs_with_gnat how-gnatmake-works}@anchor{e9} +@subsection How @emph{gnatmake} Works + + +Generally @emph{gnatmake} automatically performs all necessary +recompilations and you don't need to worry about how it works. However, +it may be useful to have some basic understanding of the @emph{gnatmake} +approach and in particular to understand how it uses the results of +previous compilations without incorrectly depending on them. + +First a definition: an object file is considered @emph{up to date} if the +corresponding ALI file exists and if all the source files listed in the +dependency section of this ALI file have time stamps matching those in +the ALI file. This means that neither the source file itself nor any +files that it depends on have been modified, and hence there is no need +to recompile this file. + +@emph{gnatmake} works by first checking if the specified main unit is up +to date. If so, no compilations are required for the main unit. If not, +@emph{gnatmake} compiles the main program to build a new ALI file that +reflects the latest sources. Then the ALI file of the main unit is +examined to find all the source files on which the main program depends, +and @emph{gnatmake} recursively applies the above procedure on all these +files. + +This process ensures that @emph{gnatmake} only trusts the dependencies +in an existing ALI file if they are known to be correct. Otherwise it +always recompiles to determine a new, guaranteed accurate set of +dependencies. As a result the program is compiled 'upside down' from what may +be more familiar as the required order of compilation in some other Ada +systems. In particular, clients are compiled before the units on which +they depend. The ability of GNAT to compile in any order is critical in +allowing an order of compilation to be chosen that guarantees that +@emph{gnatmake} will recompute a correct set of new dependencies if +necessary. + +When invoking @emph{gnatmake} with several @cite{file_names}, if a unit is +imported by several of the executables, it will be recompiled at most once. + +Note: when using non-standard naming conventions +(@ref{37,,Using Other File Names}), changing through a configuration pragmas +file the version of a source and invoking @emph{gnatmake} to recompile may +have no effect, if the previous version of the source is still accessible +by @emph{gnatmake}. It may be necessary to use the switch +-f. + +@node Examples of gnatmake Usage,,How gnatmake Works,Building with gnatmake +@anchor{gnat_ugn/building_executable_programs_with_gnat examples-of-gnatmake-usage}@anchor{ea}@anchor{gnat_ugn/building_executable_programs_with_gnat id7}@anchor{eb} +@subsection Examples of @emph{gnatmake} Usage + + + +@table @asis + +@item @emph{gnatmake hello.adb} + +Compile all files necessary to bind and link the main program +@code{hello.adb} (containing unit @cite{Hello}) and bind and link the +resulting object files to generate an executable file @code{hello}. + +@item @emph{gnatmake main1 main2 main3} + +Compile all files necessary to bind and link the main programs +@code{main1.adb} (containing unit @cite{Main1}), @code{main2.adb} +(containing unit @cite{Main2}) and @code{main3.adb} +(containing unit @cite{Main3}) and bind and link the resulting object files +to generate three executable files @code{main1}, +@code{main2} and @code{main3}. + +@item @emph{gnatmake -q Main_Unit -cargs -O2 -bargs -l} + +Compile all files necessary to bind and link the main program unit +@cite{Main_Unit} (from file @code{main_unit.adb}). All compilations will +be done with optimization level 2 and the order of elaboration will be +listed by the binder. @emph{gnatmake} will operate in quiet mode, not +displaying commands it is executing. +@end table + +@node Compiling with gcc,Compiler Switches,Building with gnatmake,Building Executable Programs with GNAT +@anchor{gnat_ugn/building_executable_programs_with_gnat compiling-with-gcc}@anchor{1e}@anchor{gnat_ugn/building_executable_programs_with_gnat id8}@anchor{ec} +@section Compiling with @emph{gcc} + + +This section discusses how to compile Ada programs using the @emph{gcc} command. It also describes the set of switches that can be used to control the behavior of the compiler. + @menu -* Compiling Programs:: -* Switches for gcc:: -* Search Paths and the Run-Time Library (RTL):: -* Order of Compilation Issues:: -* Examples:: +* Compiling Programs:: +* Search Paths and the Run-Time Library (RTL): Search Paths and the Run-Time Library RTL. +* Order of Compilation Issues:: +* Examples:: + @end menu -@node Compiling Programs -@section Compiling Programs +@node Compiling Programs,Search Paths and the Run-Time Library RTL,,Compiling with gcc +@anchor{gnat_ugn/building_executable_programs_with_gnat compiling-programs}@anchor{ed}@anchor{gnat_ugn/building_executable_programs_with_gnat id9}@anchor{ee} +@subsection Compiling Programs + -@noindent The first step in creating an executable program is to compile the units -of the program using the @command{gcc} command. You must compile the +of the program using the @emph{gcc} command. You must compile the following files: -@itemize @bullet -@item -the body file (@file{.adb}) for a library level subprogram or generic + +@itemize * + +@item +the body file (@code{.adb}) for a library level subprogram or generic subprogram -@item -the spec file (@file{.ads}) for a library level package or generic +@item +the spec file (@code{.ads}) for a library level package or generic package that has no body -@item -the body file (@file{.adb}) for a library level package +@item +the body file (@code{.adb}) for a library level package or generic package that has a body - @end itemize -@noindent You need @emph{not} compile the following files -@itemize @bullet -@item +@itemize * + +@item the spec of a library unit which has a body -@item +@item subunits @end itemize -@noindent because they are compiled as part of compiling related units. GNAT package specs when the corresponding body is compiled, and subunits when the parent is compiled. -@cindex cannot generate code +@geindex cannot generate code + If you attempt to compile any of these files, you will get one of the -following error messages (where @var{fff} is the name of the file you +following error messages (where @cite{fff} is the name of the file you compiled): -@smallexample -cannot generate code for file @var{fff} (package spec) +@quotation + +@example +cannot generate code for file `fff` (package spec) to check package spec, use -gnatc -cannot generate code for file @var{fff} (missing subunits) +cannot generate code for file `fff` (missing subunits) to check parent unit, use -gnatc -cannot generate code for file @var{fff} (subprogram spec) +cannot generate code for file `fff` (subprogram spec) to check subprogram spec, use -gnatc -cannot generate code for file @var{fff} (subunit) +cannot generate code for file `fff` (subunit) to check subunit, use -gnatc -@end smallexample +@end example +@end quotation -@noindent As indicated by the above error messages, if you want to submit one of these files to the compiler to check for correct semantics -without generating code, then use the @option{-gnatc} switch. +without generating code, then use the @emph{-gnatc} switch. -The basic command for compiling a file containing an Ada unit is +The basic command for compiling a file containing an Ada unit is: -@smallexample -@c $ gcc -c @ovar{switches} @file{file name} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gcc -c @r{[}@var{switches}@r{]} @file{file name} -@end smallexample +@example +$ gcc -c [switches] <file name> +@end example -@noindent -where @var{file name} is the name of the Ada file (usually -having an extension -@file{.ads} for a spec or @file{.adb} for a body). +where @cite{file name} is the name of the Ada file (usually +having an extension @code{.ads} for a spec or @code{.adb} for a body). You specify the -@option{-c} switch to tell @command{gcc} to compile, but not link, the file. +@code{-c} switch to tell @emph{gcc} to compile, but not link, the file. The result of a successful compilation is an object file, which has the -same name as the source file but an extension of @file{.o} and an Ada +same name as the source file but an extension of @code{.o} and an Ada Library Information (ALI) file, which also has the same name as the -source file, but with @file{.ali} as the extension. GNAT creates these +source file, but with @code{.ali} as the extension. GNAT creates these two output files in the current directory, but you may specify a source file in any directory using an absolute or relative path specification containing the directory information. -@findex gnat1 -@command{gcc} is actually a driver program that looks at the extensions of +@geindex gnat1 + +@emph{gcc} is actually a driver program that looks at the extensions of the file arguments and loads the appropriate compiler. For example, the -GNU C compiler is @file{cc1}, and the Ada compiler is @file{gnat1}. +GNU C compiler is @code{cc1}, and the Ada compiler is @code{gnat1}. These programs are in directories known to the driver program (in some configurations via environment variables you set), but need not be in -your path. The @command{gcc} driver also calls the assembler and any other +your path. The @emph{gcc} driver also calls the assembler and any other utilities needed to complete the generation of the required object files. -It is possible to supply several file names on the same @command{gcc} -command. This causes @command{gcc} to call the appropriate compiler for +It is possible to supply several file names on the same @emph{gcc} +command. This causes @emph{gcc} to call the appropriate compiler for each file. For example, the following command lists two separate files to be compiled: -@smallexample +@example $ gcc -c x.adb y.adb -@end smallexample +@end example + +calls @cite{gnat1} (the Ada compiler) twice to compile @code{x.adb} and +@code{y.adb}. +The compiler generates two object files @code{x.o} and @code{y.o} +and the two ALI files @code{x.ali} and @code{y.ali}. + +Any switches apply to all the files listed, see @ref{ef,,Compiler Switches} for a +list of available @emph{gcc} switches. + +@node Search Paths and the Run-Time Library RTL,Order of Compilation Issues,Compiling Programs,Compiling with gcc +@anchor{gnat_ugn/building_executable_programs_with_gnat id10}@anchor{f0}@anchor{gnat_ugn/building_executable_programs_with_gnat search-paths-and-the-run-time-library-rtl}@anchor{8e} +@subsection Search Paths and the Run-Time Library (RTL) + + +With the GNAT source-based library system, the compiler must be able to +find source files for units that are needed by the unit being compiled. +Search paths are used to guide this process. + +The compiler compiles one source file whose name must be given +explicitly on the command line. In other words, no searching is done +for this file. To find all other source files that are needed (the most +common being the specs of units), the compiler examines the following +directories, in the following order: + + +@itemize * + +@item +The directory containing the source file of the main unit being compiled +(the file name on the command line). + +@item +Each directory named by an @emph{-I} switch given on the @emph{gcc} +command line, in the order given. + +@geindex ADA_PRJ_INCLUDE_FILE + +@item +Each of the directories listed in the text file whose name is given +by the +@geindex ADA_PRJ_INCLUDE_FILE +@geindex environment variable; ADA_PRJ_INCLUDE_FILE +@code{ADA_PRJ_INCLUDE_FILE} environment variable. +@geindex ADA_PRJ_INCLUDE_FILE +@geindex environment variable; ADA_PRJ_INCLUDE_FILE +@code{ADA_PRJ_INCLUDE_FILE} is normally set by gnatmake or by the gnat +driver when project files are used. It should not normally be set +by other means. + +@geindex ADA_INCLUDE_PATH + +@item +Each of the directories listed in the value of the +@geindex ADA_INCLUDE_PATH +@geindex environment variable; ADA_INCLUDE_PATH +@code{ADA_INCLUDE_PATH} environment variable. +Construct this value +exactly as the +@geindex PATH +@geindex environment variable; PATH +@code{PATH} environment variable: a list of directory +names separated by colons (semicolons when working with the NT version). + +@item +The content of the @code{ada_source_path} file which is part of the GNAT +installation tree and is used to store standard libraries such as the +GNAT Run Time Library (RTL) source files. +@ref{8b,,Installing a library} +@end itemize + +Specifying the switch @emph{-I-} +inhibits the use of the directory +containing the source file named in the command line. You can still +have this directory on your search path, but in this case it must be +explicitly requested with a @emph{-I} switch. + +Specifying the switch @emph{-nostdinc} +inhibits the search of the default location for the GNAT Run Time +Library (RTL) source files. + +The compiler outputs its object files and ALI files in the current +working directory. +Caution: The object file can be redirected with the @emph{-o} switch; +however, @emph{gcc} and @cite{gnat1} have not been coordinated on this +so the @code{ALI} file will not go to the right place. Therefore, you should +avoid using the @emph{-o} switch. + +@geindex System.IO + +The packages @cite{Ada}, @cite{System}, and @cite{Interfaces} and their +children make up the GNAT RTL, together with the simple @cite{System.IO} +package used in the @cite{"Hello World"} example. The sources for these units +are needed by the compiler and are kept together in one directory. Not +all of the bodies are needed, but all of the sources are kept together +anyway. In a normal installation, you need not specify these directory +names when compiling or binding. Either the environment variables or +the built-in defaults cause these files to be found. + +In addition to the language-defined hierarchies (@cite{System}, @cite{Ada} and +@cite{Interfaces}), the GNAT distribution provides a fourth hierarchy, +consisting of child units of @cite{GNAT}. This is a collection of generally +useful types, subprograms, etc. See the @cite{GNAT_Reference_Manual} +for further details. + +Besides simplifying access to the RTL, a major use of search paths is +in compiling sources from multiple directories. This can make +development environments much more flexible. + +@node Order of Compilation Issues,Examples,Search Paths and the Run-Time Library RTL,Compiling with gcc +@anchor{gnat_ugn/building_executable_programs_with_gnat id11}@anchor{f1}@anchor{gnat_ugn/building_executable_programs_with_gnat order-of-compilation-issues}@anchor{f2} +@subsection Order of Compilation Issues + + +If, in our earlier example, there was a spec for the @cite{hello} +procedure, it would be contained in the file @code{hello.ads}; yet this +file would not have to be explicitly compiled. This is the result of the +model we chose to implement library management. Some of the consequences +of this model are as follows: + + +@itemize * + +@item +There is no point in compiling specs (except for package +specs with no bodies) because these are compiled as needed by clients. If +you attempt a useless compilation, you will receive an error message. +It is also useless to compile subunits because they are compiled as needed +by the parent. + +@item +There are no order of compilation requirements: performing a +compilation never obsoletes anything. The only way you can obsolete +something and require recompilations is to modify one of the +source files on which it depends. + +@item +There is no library as such, apart from the ALI files +(@ref{44,,The Ada Library Information Files}, for information on the format +of these files). For now we find it convenient to create separate ALI files, +but eventually the information therein may be incorporated into the object +file directly. + +@item +When you compile a unit, the source files for the specs of all units +that it @emph{with}s, all its subunits, and the bodies of any generics it +instantiates must be available (reachable by the search-paths mechanism +described above), or you will receive a fatal error message. +@end itemize + +@node Examples,,Order of Compilation Issues,Compiling with gcc +@anchor{gnat_ugn/building_executable_programs_with_gnat id12}@anchor{f3}@anchor{gnat_ugn/building_executable_programs_with_gnat examples}@anchor{f4} +@subsection Examples + + +The following are some typical Ada compilation command line examples: + +@example +$ gcc -c xyz.adb +@end example + +Compile body in file @code{xyz.adb} with all default options. + +@example +$ gcc -c -O2 -gnata xyz-def.adb +@end example -@noindent -calls @code{gnat1} (the Ada compiler) twice to compile @file{x.adb} and -@file{y.adb}. -The compiler generates two object files @file{x.o} and @file{y.o} -and the two ALI files @file{x.ali} and @file{y.ali}. -Any switches apply to all the files listed, +Compile the child unit package in file @code{xyz-def.adb} with extensive +optimizations, and pragma @cite{Assert}/@cite{Debug} statements +enabled. + +@example +$ gcc -c -gnatc abc-def.adb +@end example + +Compile the subunit in file @code{abc-def.adb} in semantic-checking-only +mode. -@node Switches for gcc -@section Switches for @command{gcc} +@node Compiler Switches,Binding with gnatbind,Compiling with gcc,Building Executable Programs with GNAT +@anchor{gnat_ugn/building_executable_programs_with_gnat compiler-switches}@anchor{f5}@anchor{gnat_ugn/building_executable_programs_with_gnat switches-for-gcc}@anchor{ef} +@section Compiler Switches -@noindent -The @command{gcc} command accepts switches that control the -compilation process. These switches are fully described in this section. -First we briefly list all the switches, in alphabetical order, then we -describe the switches in more detail in functionally grouped sections. + +The @emph{gcc} command accepts switches that control the +compilation process. These switches are fully described in this section: +first an alphabetical listing of all switches with a brief description, +and then functionally grouped sets of switches with more detailed +information. More switches exist for GCC than those documented here, especially for specific targets. However, their use is not recommended as @@ -3432,192 +8536,328 @@ the Ada run-time library, or can cause inconsistencies between compilation units. @menu -* Output and Error Message Control:: -* Warning Message Control:: -* Debugging and Assertion Control:: -* Validity Checking:: -* Style Checking:: -* Run-Time Checks:: -* Using gcc for Syntax Checking:: -* Using gcc for Semantic Checking:: -* Compiling Different Versions of Ada:: -* Character Set Control:: -* File Naming Control:: -* Subprogram Inlining Control:: -* Auxiliary Output Control:: -* Debugging Control:: -* Exception Handling Control:: -* Units to Sources Mapping Files:: -* Integrated Preprocessing:: -* Code Generation Control:: +* Alphabetical List of All Switches:: +* Output and Error Message Control:: +* Warning Message Control:: +* Debugging and Assertion Control:: +* Validity Checking:: +* Style Checking:: +* Run-Time Checks:: +* Using gcc for Syntax Checking:: +* Using gcc for Semantic Checking:: +* Compiling Different Versions of Ada:: +* Character Set Control:: +* File Naming Control:: +* Subprogram Inlining Control:: +* Auxiliary Output Control:: +* Debugging Control:: +* Exception Handling Control:: +* Units to Sources Mapping Files:: +* Code Generation Control:: + @end menu -@table @option -@c !sort! -@cindex @option{-b} (@command{gcc}) -@item -b @var{target} -Compile your program to run on @var{target}, which is the name of a +@node Alphabetical List of All Switches,Output and Error Message Control,,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat id13}@anchor{f6}@anchor{gnat_ugn/building_executable_programs_with_gnat alphabetical-list-of-all-switches}@anchor{f7} +@subsection Alphabetical List of All Switches + + +@geindex -b (gcc) + + +@table @asis + +@item @code{-b @emph{target}} + +Compile your program to run on @cite{target}, which is the name of a system configuration. You must have a GNAT cross-compiler built if -@var{target} is not the same as your host system. +@cite{target} is not the same as your host system. +@end table + +@geindex -B (gcc) + -@item -B@var{dir} -@cindex @option{-B} (@command{gcc}) -Load compiler executables (for example, @code{gnat1}, the Ada compiler) -from @var{dir} instead of the default location. Only use this switch +@table @asis + +@item @code{-B@emph{dir}} + +Load compiler executables (for example, @cite{gnat1}, the Ada compiler) +from @cite{dir} instead of the default location. Only use this switch when multiple versions of the GNAT compiler are available. -@xref{Directory Options,, Options for Directory Search, gcc, Using the -GNU Compiler Collection (GCC)}, for further details. You would normally -use the @option{-b} or @option{-V} switch instead. +See the "Options for Directory Search" section in the +@cite{Using the GNU Compiler Collection (GCC)} manual for further details. +You would normally use the @emph{-b} or @emph{-V} switch instead. +@end table + +@geindex -c (gcc) + + +@table @asis + +@item @code{-c} -@item -c -@cindex @option{-c} (@command{gcc}) Compile. Always use this switch when compiling Ada programs. -Note: for some other languages when using @command{gcc}, notably in +Note: for some other languages when using @emph{gcc}, notably in the case of C and C++, it is possible to use -use @command{gcc} without a @option{-c} switch to +use @emph{gcc} without a @emph{-c} switch to compile and link in one step. In the case of GNAT, you cannot use this approach, because the binder must be run -and @command{gcc} cannot be used to run the GNAT binder. +and @emph{gcc} cannot be used to run the GNAT binder. +@end table + +@geindex -fcallgraph-info (gcc) + + +@table @asis + +@item @code{-fcallgraph-info[=su,da]} -@item -fcallgraph-info@r{[}=su,da@r{]} -@cindex @option{-fcallgraph-info} (@command{gcc}) Makes the compiler output callgraph information for the program, on a per-file basis. The information is generated in the VCG format. It can be decorated with additional, per-node and/or per-edge information, if a list of comma-separated markers is additionally specified. When the -@var{su} marker is specified, the callgraph is decorated with stack usage information; it is equivalent to @option{-fstack-usage}. When the @var{da} +@cite{su} marker is specified, the callgraph is decorated with stack usage +information; it is equivalent to @emph{-fstack-usage}. When the @cite{da} marker is specified, the callgraph is decorated with information about dynamically allocated objects. +@end table + +@geindex -fdump-scos (gcc) + + +@table @asis + +@item @code{-fdump-scos} -@item -fdump-scos -@cindex @option{-fdump-scos} (@command{gcc}) Generates SCO (Source Coverage Obligation) information in the ALI file. -This information is used by advanced coverage tools. See unit @file{SCOs} -in the compiler sources for details in files @file{scos.ads} and -@file{scos.adb}. +This information is used by advanced coverage tools. See unit @code{SCOs} +in the compiler sources for details in files @code{scos.ads} and +@code{scos.adb}. +@end table + +@geindex -fdump-xref (gcc) + + +@table @asis + +@item @code{-fdump-xref} -@item -fdump-xref -@cindex @option{-fdump-xref} (@command{gcc}) Generates cross reference information in GLI files for C and C++ sources. The GLI files have the same syntax as the ALI files for Ada, and can be used for source navigation in IDEs and on the command line using e.g. gnatxref -and the @option{--ext=gli} switch. +and the @emph{--ext=gli} switch. +@end table + +@geindex -flto (gcc) + + +@table @asis + +@item @code{-flto[=@emph{n}]} -@item -flto@r{[}=n@r{]} -@cindex @option{-flto} (@command{gcc}) Enables Link Time Optimization. This switch must be used in conjunction -with the traditional @option{-Ox} switches and instructs the compiler to +with the traditional @emph{-Ox} switches and instructs the compiler to defer most optimizations until the link stage. The advantage of this approach is that the compiler can do a whole-program analysis and choose the best interprocedural optimization strategy based on a complete view of the program, instead of a fragmentary view with the usual approach. This can also speed up the compilation of big programs and reduce the size of the executable, compared with a traditional per-unit compilation -with inlining across modules enabled by the @option{-gnatn} switch. +with inlining across modules enabled by the @emph{-gnatn} switch. The drawback of this approach is that it may require more memory and that the debugging information generated by -g with it might be hardly usable. -The switch, as well as the accompanying @option{-Ox} switches, must be +The switch, as well as the accompanying @emph{-Ox} switches, must be specified both for the compilation and the link phases. -If the @var{n} parameter is specified, the optimization and final code -generation at link time are executed using @var{n} parallel jobs by -means of an installed @command{make} program. - -@item -fno-inline -@cindex @option{-fno-inline} (@command{gcc}) -Suppresses all inlining, even if other optimization or inlining -switches are set. This includes suppression of inlining that -results from the use of the pragma @code{Inline_Always}. -Any occurrences of pragma @code{Inline} or @code{Inline_Always} -are ignored, and @option{-gnatn} and @option{-gnatN} have no -effects if this switch is present. Note that inlining can also -be suppressed on a finer-grained basis with pragma @code{No_Inline}. - -@item -fno-inline-functions -@cindex @option{-fno-inline-functions} (@command{gcc}) +If the @cite{n} parameter is specified, the optimization and final code +generation at link time are executed using @cite{n} parallel jobs by +means of an installed @emph{make} program. +@end table + +@geindex -fno-inline (gcc) + + +@table @asis + +@item @code{-fno-inline} + +Suppresses all inlining, unless requested with pragma @cite{Inline_Always}. The +effect is enforced regardless of other optimization or inlining switches. +Note that inlining can also be suppressed on a finer-grained basis with +pragma @cite{No_Inline}. +@end table + +@geindex -fno-inline-functions (gcc) + + +@table @asis + +@item @code{-fno-inline-functions} + Suppresses automatic inlining of subprograms, which is enabled -if @option{-O3} is used. +if @emph{-O3} is used. +@end table + +@geindex -fno-inline-small-functions (gcc) + + +@table @asis + +@item @code{-fno-inline-small-functions} -@item -fno-inline-small-functions -@cindex @option{-fno-inline-small-functions} (@command{gcc}) Suppresses automatic inlining of small subprograms, which is enabled -if @option{-O2} is used. +if @emph{-O2} is used. +@end table + +@geindex -fno-inline-functions-called-once (gcc) + + +@table @asis + +@item @code{-fno-inline-functions-called-once} -@item -fno-inline-functions-called-once -@cindex @option{-fno-inline-functions-called-once} (@command{gcc}) Suppresses inlining of subprograms local to the unit and called once -from within it, which is enabled if @option{-O1} is used. +from within it, which is enabled if @emph{-O1} is used. +@end table + +@geindex -fno-ivopts (gcc) + + +@table @asis + +@item @code{-fno-ivopts} -@item -fno-ivopts -@cindex @option{-fno-ivopts} (@command{gcc}) Suppresses high-level loop induction variable optimizations, which are -enabled if @option{-O1} is used. These optimizations are generally +enabled if @emph{-O1} is used. These optimizations are generally profitable but, for some specific cases of loops with numerous uses of the iteration variable that follow a common pattern, they may end up destroying the regularity that could be exploited at a lower level and thus producing inferior code. +@end table + +@geindex -fno-strict-aliasing (gcc) + + +@table @asis + +@item @code{-fno-strict-aliasing} -@item -fno-strict-aliasing -@cindex @option{-fno-strict-aliasing} (@command{gcc}) Causes the compiler to avoid assumptions regarding non-aliasing of objects of different types. See -@ref{Optimization and Strict Aliasing} for details. +@ref{f8,,Optimization and Strict Aliasing} for details. +@end table + +@geindex -fstack-check (gcc) + + +@table @asis + +@item @code{-fstack-check} -@item -fstack-check -@cindex @option{-fstack-check} (@command{gcc}) Activates stack checking. -See @ref{Stack Overflow Checking} for details. +See @ref{f9,,Stack Overflow Checking} for details. +@end table + +@geindex -fstack-usage (gcc) + + +@table @asis + +@item @code{-fstack-usage} -@item -fstack-usage -@cindex @option{-fstack-usage} (@command{gcc}) Makes the compiler output stack usage information for the program, on a -per-subprogram basis. See @ref{Static Stack Usage Analysis} for details. +per-subprogram basis. See @ref{fa,,Static Stack Usage Analysis} for details. +@end table + +@geindex -g (gcc) + + +@table @asis + +@item @code{-g} -@item -g -@cindex @option{-g} (@command{gcc}) Generate debugging information. This information is stored in the object file and copied from there to the final executable file by the linker, where it can be read by the debugger. You must use the -@option{-g} switch if you plan on using the debugger. +@emph{-g} switch if you plan on using the debugger. +@end table + +@geindex -gnat05 (gcc) + + +@table @asis + +@item @code{-gnat05} + +Allow full Ada 2005 features. +@end table + +@geindex -gnat12 (gcc) + + +@table @asis + +@item @code{-gnat12} + +Allow full Ada 2012 features. +@end table + +@geindex -gnat83 (gcc) + +@geindex -gnat2005 (gcc) + + +@table @asis + +@item @code{-gnat2005} + +Allow full Ada 2005 features (same as @emph{-gnat05}) +@end table + +@geindex -gnat2012 (gcc) + + +@table @asis + +@item @code{-gnat2012} + +Allow full Ada 2012 features (same as @emph{-gnat12}) + +@item @code{-gnat83} -@item -gnat83 -@cindex @option{-gnat83} (@command{gcc}) Enforce Ada 83 restrictions. +@end table + +@geindex -gnat95 (gcc) + + +@table @asis + +@item @code{-gnat95} -@item -gnat95 -@cindex @option{-gnat95} (@command{gcc}) Enforce Ada 95 restrictions. Note: for compatibility with some Ada 95 compilers which support only -the @code{overriding} keyword of Ada 2005, the @option{-gnatd.D} switch can -be used along with @option{-gnat95} to achieve a similar effect with GNAT. +the @cite{overriding} keyword of Ada 2005, the @emph{-gnatd.D} switch can +be used along with @emph{-gnat95} to achieve a similar effect with GNAT. -@option{-gnatd.D} instructs GNAT to consider @code{overriding} as a keyword +@emph{-gnatd.D} instructs GNAT to consider @cite{overriding} as a keyword and handle its associated semantic checks, even in Ada 95 mode. +@end table -@item -gnat05 -@cindex @option{-gnat05} (@command{gcc}) -Allow full Ada 2005 features. +@geindex -gnata (gcc) -@item -gnat2005 -@cindex @option{-gnat2005} (@command{gcc}) -Allow full Ada 2005 features (same as @option{-gnat05}) -@item -gnat12 -@cindex @option{-gnat12} (@command{gcc}) +@table @asis -@item -gnat2012 -@cindex @option{-gnat2012} (@command{gcc}) -Allow full Ada 2012 features (same as @option{-gnat12}) +@item @code{-gnata} -@item -gnata -@cindex @option{-gnata} (@command{gcc}) -Assertions enabled. @code{Pragma Assert} and @code{pragma Debug} to be +Assertions enabled. @cite{Pragma Assert} and @cite{pragma Debug} to be activated. Note that these pragmas can also be controlled using the -configuration pragmas @code{Assertion_Policy} and @code{Debug_Policy}. -It also activates pragmas @code{Check}, @code{Precondition}, and -@code{Postcondition}. Note that these pragmas can also be controlled -using the configuration pragma @code{Check_Policy}. In Ada 2012, it +configuration pragmas @cite{Assertion_Policy} and @cite{Debug_Policy}. +It also activates pragmas @cite{Check}, @cite{Precondition}, and +@cite{Postcondition}. Note that these pragmas can also be controlled +using the configuration pragma @cite{Check_Policy}. In Ada 2012, it also activates all assertions defined in the RM as aspects: preconditions, postconditions, type invariants and (sub)type predicates. In all Ada modes, corresponding pragmas for type invariants and (sub)type predicates are @@ -3625,68 +8865,116 @@ also activated. The default is that all these assertions are disabled, and have no effect, other than being checked for syntactic validity, and in the case of subtype predicates, constructions such as membership tests still test predicates even if assertions are turned off. +@end table + +@geindex -gnatA (gcc) + + +@table @asis + +@item @code{-gnatA} -@item -gnatA -@cindex @option{-gnatA} (@command{gcc}) -Avoid processing @file{gnat.adc}. If a @file{gnat.adc} file is present, +Avoid processing @code{gnat.adc}. If a @code{gnat.adc} file is present, it will be ignored. +@end table + +@geindex -gnatb (gcc) -@item -gnatb -@cindex @option{-gnatb} (@command{gcc}) -Generate brief messages to @file{stderr} even if verbose mode set. -@item -gnatB -@cindex @option{-gnatB} (@command{gcc}) +@table @asis + +@item @code{-gnatb} + +Generate brief messages to @code{stderr} even if verbose mode set. +@end table + +@geindex -gnatB (gcc) + + +@table @asis + +@item @code{-gnatB} + Assume no invalid (bad) values except for 'Valid attribute use -(@pxref{Validity Checking}). +(@ref{fb,,Validity Checking}). +@end table + +@geindex -gnatc (gcc) + + +@table @asis + +@item @code{-gnatc} -@item -gnatc -@cindex @option{-gnatc} (@command{gcc}) Check syntax and semantics only (no code generation attempted). When the -compiler is invoked by @command{gnatmake}, if the switch @option{-gnatc} is -only given to the compiler (after @option{-cargs} or in package Compiler of -the project file, @command{gnatmake} will fail because it will not find the -object file after compilation. If @command{gnatmake} is called with -@option{-gnatc} as a builder switch (before @option{-cargs} or in package -Builder of the project file) then @command{gnatmake} will not fail because +compiler is invoked by @emph{gnatmake}, if the switch @emph{-gnatc} is +only given to the compiler (after @emph{-cargs} or in package Compiler of +the project file, @emph{gnatmake} will fail because it will not find the +object file after compilation. If @emph{gnatmake} is called with +@emph{-gnatc} as a builder switch (before @emph{-cargs} or in package +Builder of the project file) then @emph{gnatmake} will not fail because it will not look for the object files after compilation, and it will not try -to build and link. This switch may not be given if a previous @code{-gnatR} -switch has been given, since @code{-gnatR} requires that the code generator +to build and link. This switch may not be given if a previous @cite{-gnatR} +switch has been given, since @cite{-gnatR} requires that the code generator be called to complete determination of representation information. +@end table + +@geindex -gnatC (gcc) + + +@table @asis + +@item @code{-gnatC} -@item -gnatC -@cindex @option{-gnatC} (@command{gcc}) Generate CodePeer intermediate format (no code generation attempted). This switch will generate an intermediate representation suitable for -use by CodePeer (@file{.scil} files). This switch is not compatible with +use by CodePeer (@code{.scil} files). This switch is not compatible with code generation (it will, among other things, disable some switches such as -gnatn, and enable others such as -gnata). +@end table + +@geindex -gnatd (gcc) + + +@table @asis + +@item @code{-gnatd} -@item -gnatd -@cindex @option{-gnatd} (@command{gcc}) Specify debug options for the compiler. The string of characters after -the @option{-gnatd} specify the specific debug options. The possible +the @emph{-gnatd} specify the specific debug options. The possible characters are 0-9, a-z, A-Z, optionally preceded by a dot. See -compiler source file @file{debug.adb} for details of the implemented +compiler source file @code{debug.adb} for details of the implemented debug options. Certain debug options are relevant to applications programmers, and these are documented at appropriate points in this users guide. +@end table + +@geindex -gnatD[nn] (gcc) + + +@table @asis + +@item @code{-gnatD} -@item -gnatD -@cindex @option{-gnatD[nn]} (@command{gcc}) Create expanded source files for source level debugging. This switch also suppress generation of cross-reference information -(see @option{-gnatx}). Note that this switch is not allowed if a previous +(see @emph{-gnatx}). Note that this switch is not allowed if a previous -gnatR switch has been given, since these two switches are not compatible. +@end table + +@geindex -gnateA (gcc) + + +@table @asis + +@item @code{-gnateA} -@item -gnateA -@cindex @option{-gnateA} (@command{gcc}) Check that the actual parameters of a subprogram call are not aliases of one another. To qualify as aliasing, the actuals must denote objects of a composite type, their memory locations must be identical or overlapping, and at least one of the corresponding formal parameters must be of mode OUT or IN OUT. -@smallexample +@example type Rec_Typ is record Data : Integer := 0; end record; @@ -3705,117 +8993,225 @@ Obj : Rec_Typ; Detect_Aliasing (Obj, Obj); Detect_Aliasing (Obj, Self (Obj)); -@end smallexample +@end example -In the example above, the first call to @code{Detect_Aliasing} fails with a -@code{Program_Error} at runtime because the actuals for @code{Val_1} and -@code{Val_2} denote the same object. The second call executes without raising -an exception because @code{Self(Obj)} produces an anonymous object which does -not share the memory location of @code{Obj}. +In the example above, the first call to @cite{Detect_Aliasing} fails with a +@cite{Program_Error} at runtime because the actuals for @cite{Val_1} and +@cite{Val_2} denote the same object. The second call executes without raising +an exception because @cite{Self(Obj)} produces an anonymous object which does +not share the memory location of @cite{Obj}. +@end table + +@geindex -gnatec (gcc) + + +@table @asis + +@item @code{-gnatec=@emph{path}} -@item -gnatec=@var{path} -@cindex @option{-gnatec} (@command{gcc}) Specify a configuration pragma file (the equal sign is optional) -(@pxref{The Configuration Pragmas Files}). +(@ref{7b,,The Configuration Pragmas Files}). +@end table + +@geindex -gnateC (gcc) + + +@table @asis + +@item @code{-gnateC} -@item -gnateC -@cindex @option{-gnateC} (@command{gcc}) Generate CodePeer messages in a compiler-like format. This switch is only -effective if @option{-gnatcC} is also specified and requires an installation +effective if @emph{-gnatcC} is also specified and requires an installation of CodePeer. +@end table + +@geindex -gnated (gcc) + + +@table @asis + +@item @code{-gnated} -@item -gnated -@cindex @option{-gnated} (@command{gcc}) Disable atomic synchronization +@end table + +@geindex -gnateD (gcc) + + +@table @asis + +@item @code{-gnateDsymbol[=@emph{value}]} -@item -gnateDsymbol@r{[}=@var{value}@r{]} -@cindex @option{-gnateD} (@command{gcc}) -Defines a symbol, associated with @var{value}, for preprocessing. -(@pxref{Integrated Preprocessing}). +Defines a symbol, associated with @cite{value}, for preprocessing. +(@ref{1a,,Integrated Preprocessing}). +@end table + +@geindex -gnateE (gcc) + + +@table @asis + +@item @code{-gnateE} -@item -gnateE -@cindex @option{-gnateE} (@command{gcc}) Generate extra information in exception messages. In particular, display extra column information and the value and range associated with index and range check failures, and extra column information for access checks. In cases where the compiler is able to determine at compile time that a check will fail, it gives a warning, and the extra information is not produced at run time. +@end table + +@geindex -gnatef (gcc) + + +@table @asis + +@item @code{-gnatef} -@item -gnatef -@cindex @option{-gnatef} (@command{gcc}) Display full source path name in brief error messages. +@end table + +@geindex -gnateF (gcc) + + +@table @asis + +@item @code{-gnateF} -@item -gnateF -@cindex @option{-gnateF} (@command{gcc}) Check for overflow on all floating-point operations, including those for unconstrained predefined types. See description of pragma -@code{Check_Float_Overflow} in GNAT RM. +@cite{Check_Float_Overflow} in GNAT RM. +@end table + +@geindex -gnateG (gcc) + + +@table @asis + +@item @code{-gnateG} -@item -gnateG -@cindex @option{-gnateG} (@command{gcc}) Save result of preprocessing in a text file. +@end table + +@geindex -gnatei (gcc) + + +@table @asis + +@item @code{-gnatei@emph{nnn}} -@item -gnatei@var{nnn} -@cindex @option{-gnatei} (@command{gcc}) Set maximum number of instantiations during compilation of a single unit to -@var{nnn}. This may be useful in increasing the default maximum of 8000 for +@cite{nnn}. This may be useful in increasing the default maximum of 8000 for the rare case when a single unit legitimately exceeds this limit. +@end table + +@geindex -gnateI (gcc) + + +@table @asis + +@item @code{-gnateI@emph{nnn}} -@item -gnateI@var{nnn} -@cindex @option{-gnateI} (@command{gcc}) Indicates that the source is a multi-unit source and that the index of the -unit to compile is @var{nnn}. @var{nnn} needs to be a positive number and need +unit to compile is @cite{nnn}. @cite{nnn} needs to be a positive number and need to be a valid index in the multi-unit source. +@end table + +@geindex -gnatel (gcc) + + +@table @asis + +@item @code{-gnatel} -@item -gnatel -@cindex @option{-gnatel} (@command{gcc}) This switch can be used with the static elaboration model to issue info messages showing -where implicit @code{pragma Elaborate} and @code{pragma Elaborate_All} +where implicit @cite{pragma Elaborate} and @cite{pragma Elaborate_All} are generated. This is useful in diagnosing elaboration circularities caused by these implicit pragmas when using the static elaboration model. See See the section in this guide on elaboration checking for further details. These messages are not generated by default, and are intended only for temporary use when debugging circularity problems. +@end table + +@geindex -gnatel (gcc) + + +@table @asis + +@item @code{-gnateL} -@item -gnateL -@cindex @option{-gnatel} (@command{gcc}) This switch turns off the info messages about implicit elaboration pragmas. +@end table + +@geindex -gnatem (gcc) + + +@table @asis + +@item @code{-gnatem=@emph{path}} -@item -gnatem=@var{path} -@cindex @option{-gnatem} (@command{gcc}) Specify a mapping file (the equal sign is optional) -(@pxref{Units to Sources Mapping Files}). +(@ref{fc,,Units to Sources Mapping Files}). +@end table + +@geindex -gnatep (gcc) + + +@table @asis + +@item @code{-gnatep=@emph{file}} -@item -gnatep=@var{file} -@cindex @option{-gnatep} (@command{gcc}) Specify a preprocessing data file (the equal sign is optional) -(@pxref{Integrated Preprocessing}). +(@ref{1a,,Integrated Preprocessing}). +@end table + +@geindex -gnateP (gcc) + + +@table @asis + +@item @code{-gnateP} -@item -gnateP -@cindex @option{-gnateP} (@command{gcc}) Turn categorization dependency errors into warnings. Ada requires that units that WITH one another have compatible categories, for example a Pure unit cannot WITH a Preelaborate unit. If this switch is used, these errors become warnings (which can be ignored, or suppressed in the usual manner). This can be useful in some specialized circumstances such as the temporary use of special test software. +@end table + +@geindex -gnateS (gcc) + + +@table @asis + +@item @code{-gnateS} + +Synonym of @emph{-fdump-scos}, kept for backwards compatibility. +@end table + +@geindex -gnatet=file (gcc) + + +@table @asis -@item -gnateS -@cindex @option{-gnateS} (@command{gcc}) -Synonym of @option{-fdump-scos}, kept for backwards compatibility. +@item @code{-gnatet=@emph{path}} -@item -gnatet=@var{path} -@cindex @option{-gnatet=file} (@command{gcc}) Generate target dependent information. The format of the output file is -described in the section about switch @option{-gnateT}. +described in the section about switch @emph{-gnateT}. +@end table + +@geindex -gnateT (gcc) + + +@table @asis + +@item @code{-gnateT=@emph{path}} -@item -gnateT=@var{path} -@cindex @option{-gnateT} (@command{gcc}) Read target dependent information, such as endianness or sizes and alignments of base type. If this switch is passed, the default target dependent information of the compiler is replaced by the one read from the input file. @@ -3824,11 +9220,11 @@ semantic analysis of programs that will run on some other target than the machine on which the tool is run. The following target dependent values should be defined, -where @code{Nat} denotes a natural integer value, @code{Pos} denotes a +where @cite{Nat} denotes a natural integer value, @cite{Pos} denotes a positive integer value, and fields marked with a question mark are boolean fields, where a value of 0 is False, and a value of 1 is True: -@smallexample +@example Bits_BE : Nat; -- Bits stored big-endian? Bits_Per_Unit : Pos; -- Bits in a storage unit Bits_Per_Word : Pos; -- Bits in a word @@ -3852,17 +9248,17 @@ Strict_Alignment : Nat; -- Strict alignment? System_Allocator_Alignment : Nat; -- Alignment for malloc calls Wchar_T_Size : Pos; -- Interfaces.C.wchar_t'Size Words_BE : Nat; -- Words stored big-endian? -@end smallexample +@end example The format of the input file is as follows. First come the values of the variables defined above, with one line per value: -@smallexample +@example name value -@end smallexample +@end example -where @code{name} is the name of the parameter, spelled out in full, -and cased as in the above list, and @code{value} is an unsigned decimal +where @cite{name} is the name of the parameter, spelled out in full, +and cased as in the above list, and @cite{value} is an unsigned decimal integer. Two or more blanks separates the name from the value. All the variables must be present, in alphabetical order (i.e. the @@ -3872,22 +9268,22 @@ Then there is a blank line to separate the two parts of the file. Then come the lines showing the floating-point types to be registered, with one line per registered mode: -@smallexample +@example name digs float_rep size alignment -@end smallexample +@end example -where @code{name} is the string name of the type (which can have -single spaces embedded in the name (e.g. long double), @code{digs} is -the number of digits for the floating-point type, @code{float_rep} is +where @cite{name} is the string name of the type (which can have +single spaces embedded in the name (e.g. long double), @cite{digs} is +the number of digits for the floating-point type, @cite{float_rep} is the float representation (I/V/A for IEEE-754-Binary, Vax_Native, -AAMP), @code{size} is the size in bits, @code{alignment} is the +AAMP), @cite{size} is the size in bits, @cite{alignment} is the alignment in bits. The name is followed by at least two blanks, fields are separated by at least one blank, and a LF character immediately follows the alignment field. Here is an example of a target parameterization file: -@smallexample +@example Bits_BE 0 Bits_Per_Unit 8 Bits_Per_Word 64 @@ -3915,69 +9311,134 @@ float 15 I 64 64 double 15 I 64 64 long double 18 I 80 128 TF 33 I 128 128 -@end smallexample +@end example +@end table + +@geindex -gnateu (gcc) + + +@table @asis + +@item @code{-gnateu} -@item -gnateu -@cindex @option{-gnateu} (@command{gcc}) Ignore unrecognized validity, warning, and style switches that appear after this switch is given. This may be useful when compiling sources developed on a later version of the compiler with an earlier version. Of course the earlier version must support this switch. +@end table + +@geindex -gnateV (gcc) + + +@table @asis + +@item @code{-gnateV} -@item -gnateV -@cindex @option{-gnateV} (@command{gcc}) Check that all actual parameters of a subprogram call are valid according to -the rules of validity checking (@pxref{Validity Checking}). +the rules of validity checking (@ref{fb,,Validity Checking}). +@end table + +@geindex -gnateY (gcc) + + +@table @asis + +@item @code{-gnateY} -@item -gnateY -@cindex @option{-gnateY} (@command{gcc}) Ignore all STYLE_CHECKS pragmas. Full legality checks are still carried out, but the pragmas have no effect on what style checks are active. This allows all style checking options to be controlled from the command line. +@end table + +@geindex -gnatE (gcc) + + +@table @asis + +@item @code{-gnatE} -@item -gnatE -@cindex @option{-gnatE} (@command{gcc}) Full dynamic elaboration checks. +@end table + +@geindex -gnatf (gcc) + + +@table @asis + +@item @code{-gnatf} -@item -gnatf -@cindex @option{-gnatf} (@command{gcc}) Full errors. Multiple errors per line, all undefined references, do not attempt to suppress cascaded errors. +@end table + +@geindex -gnatF (gcc) + + +@table @asis + +@item @code{-gnatF} -@item -gnatF -@cindex @option{-gnatF} (@command{gcc}) Externals names are folded to all uppercase. +@end table + +@geindex -gnatg (gcc) + + +@table @asis + +@item @code{-gnatg} -@item -gnatg -@cindex @option{-gnatg} (@command{gcc}) Internal GNAT implementation mode. This should not be used for applications programs, it is intended only for use by the compiler and its run-time library. For documentation, see the GNAT sources. -Note that @option{-gnatg} implies -@option{-gnatw.ge} and -@option{-gnatyg} +Note that @emph{-gnatg} implies +@emph{-gnatw.ge} and +@emph{-gnatyg} so that all standard warnings and all standard style options are turned on. All warnings and style messages are treated as errors. +@end table + +@geindex -gnatG[nn] (gcc) + + +@table @asis + +@item @code{-gnatG=nn} -@item -gnatG=nn -@cindex @option{-gnatG[nn]} (@command{gcc}) List generated expanded code in source form. +@end table + +@geindex -gnath (gcc) + + +@table @asis + +@item @code{-gnath} + +Output usage information. The output is written to @code{stdout}. +@end table + +@geindex -gnati (gcc) + + +@table @asis + +@item @code{-gnati@emph{c}} -@item -gnath -@cindex @option{-gnath} (@command{gcc}) -Output usage information. The output is written to @file{stdout}. +Identifier character set (@cite{c} = 1/2/3/4/8/9/p/f/n/w). +For details of the possible selections for @cite{c}, +see @ref{4a,,Character Set Control}. +@end table + +@geindex -gnatI (gcc) + + +@table @asis -@item -gnati@var{c} -@cindex @option{-gnati} (@command{gcc}) -Identifier character set -(@var{c}=1/2/3/4/8/9/p/f/n/w). -For details of the possible selections for @var{c}, -see @ref{Character Set Control}. +@item @code{-gnatI} -@item -gnatI -@cindex @option{-gnatI} (@command{gcc}) Ignore representation clauses. When this switch is used, representation clauses are treated as comments. This is useful when initially porting code where you want to ignore rep clause @@ -3990,528 +9451,868 @@ Object_Size, Size, Small, Stream_Size, and Value_Size. Note that this option should be used only for compiling -- the code is likely to malfunction at run time. -Note that when @code{-gnatct} is used to generate trees for input -into @code{ASIS} tools, these representation clauses are removed +Note that when @cite{-gnatct} is used to generate trees for input +into @cite{ASIS} tools, these representation clauses are removed from the tree and ignored. This means that the tool will not see them. +@end table + +@geindex -gnatjnn (gcc) + + +@table @asis + +@item @code{-gnatj@emph{nn}} + +Reformat error messages to fit on @cite{nn} character lines +@end table + +@geindex -gnatk (gcc) + + +@table @asis + +@item @code{-gnatk=@emph{n}} + +Limit file names to @cite{n} (1-999) characters (@cite{k} = krunch). +@end table -@item -gnatjnn -@cindex @option{-gnatjnn} (@command{gcc}) -Reformat error messages to fit on nn character lines +@geindex -gnatl (gcc) -@item -gnatk=@var{n} -@cindex @option{-gnatk} (@command{gcc}) -Limit file names to @var{n} (1-999) characters (@code{k} = krunch). -@item -gnatl -@cindex @option{-gnatl} (@command{gcc}) +@table @asis + +@item @code{-gnatl} + Output full source listing with embedded error messages. +@end table + +@geindex -gnatL (gcc) + + +@table @asis + +@item @code{-gnatL} -@item -gnatL -@cindex @option{-gnatL} (@command{gcc}) Used in conjunction with -gnatG or -gnatD to intersperse original source lines (as comment lines with line numbers) in the expanded source output. +@end table + +@geindex -gnatm (gcc) + -@item -gnatm=@var{n} -@cindex @option{-gnatm} (@command{gcc}) -Limit number of detected error or warning messages to @var{n} -where @var{n} is in the range 1..999999. The default setting if +@table @asis + +@item @code{-gnatm=@emph{n}} + +Limit number of detected error or warning messages to @cite{n} +where @cite{n} is in the range 1..999999. The default setting if no switch is given is 9999. If the number of warnings reaches this limit, then a message is output and further warnings are suppressed, but the compilation is continued. If the number of error messages reaches this limit, then a message is output and the compilation is abandoned. The equal sign here is optional. A value of zero means that no limit applies. +@end table + +@geindex -gnatn (gcc) + + +@table @asis -@item -gnatn[12] -@cindex @option{-gnatn} (@command{gcc}) -Activate inlining for subprograms for which pragma @code{Inline} is +@item @code{-gnatn[12]} + +Activate inlining for subprograms for which pragma @cite{Inline} is specified. This inlining is performed by the GCC back-end. An optional digit sets the inlining level: 1 for moderate inlining across modules or 2 for full inlining across modules. If no inlining level is specified, the compiler will pick it based on the optimization level. +@end table + +@geindex -gnatN (gcc) + + +@table @asis + +@item @code{-gnatN} -@item -gnatN -@cindex @option{-gnatN} (@command{gcc}) Activate front end inlining for subprograms for which -pragma @code{Inline} is specified. This inlining is performed +pragma @cite{Inline} is specified. This inlining is performed by the front end and will be visible in the -@option{-gnatG} output. +@emph{-gnatG} output. When using a gcc-based back end (in practice this means using any version of GNAT other than the JGNAT, .NET or GNAAMP versions), then the use of -@option{-gnatN} is deprecated, and the use of @option{-gnatn} is preferred. +@emph{-gnatN} is deprecated, and the use of @emph{-gnatn} is preferred. Historically front end inlining was more extensive than the gcc back end inlining, but that is no longer the case. +@end table + +@geindex -gnato0 (gcc) + + +@table @asis + +@item @code{-gnato0} -@item -gnato0 -@cindex @option{-gnato0} (@command{gcc}) Suppresses overflow checking. This causes the behavior of the compiler to match the default for older versions where overflow checking was suppressed by default. This is equivalent to having -@code{pragma Suppress (Overflow_Mode)} in a configuration pragma file. +@cite{pragma Suppress (Overflow_Mode)} in a configuration pragma file. +@end table + +@geindex -gnato?? (gcc) + + +@table @asis + +@item @code{-gnato??} -@item -gnato?? -@cindex @option{-gnato??} (@command{gcc}) Set default mode for handling generation of code to avoid intermediate -arithmetic overflow. Here `@code{??}' is two digits, a -single digit, or nothing. Each digit is one of the digits `@code{1}' -through `@code{3}': - -@itemize @bullet -@item @code{1}: -all intermediate overflows checked against base type (@code{STRICT}) -@item @code{2}: -minimize intermediate overflows (@code{MINIMIZED}) -@item @code{3}: -eliminate intermediate overflows (@code{ELIMINATED}) -@end itemize +arithmetic overflow. Here @cite{??} is two digits, a +single digit, or nothing. Each digit is one of the digits @cite{1} +through @cite{3}: + + +@multitable {xxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item + +Digit + +@tab + +Interpretation + +@item + +@emph{1} + +@tab + +All intermediate overflows checked against base type (@cite{STRICT}) + +@item + +@emph{2} + +@tab + +Minimize intermediate overflows (@cite{MINIMIZED}) + +@item + +@emph{3} + +@tab + +Eliminate intermediate overflows (@cite{ELIMINATED}) + +@end multitable + If only one digit appears then it applies to all cases; if two digits are given, then the first applies outside assertions, and the second within assertions. -If no digits follow the @option{-gnato}, then it is equivalent to -@option{-gnato11}, +If no digits follow the @emph{-gnato}, then it is equivalent to +@emph{-gnato11}, causing all intermediate overflows to be handled in strict mode. This switch also causes arithmetic overflow checking to be performed -(as though @code{pragma Unsuppress (Overflow_Mode)} had been specified. +(as though @cite{pragma Unsuppress (Overflow_Mode)} had been specified. -The default if no option @option{-gnato} is given is that overflow handling -is in @code{STRICT} mode (computations done using the base type), and that +The default if no option @emph{-gnato} is given is that overflow handling +is in @cite{STRICT} mode (computations done using the base type), and that overflow checking is enabled. Note that division by zero is a separate check that is not controlled by this switch (division by zero checking is on by default). -See also @ref{Specifying the Desired Mode}. +See also @ref{fd,,Specifying the Desired Mode}. +@end table + +@geindex -gnatp (gcc) + + +@table @asis + +@item @code{-gnatp} + +Suppress all checks. See @ref{fe,,Run-Time Checks} for details. This switch +has no effect if cancelled by a subsequent @emph{-gnat-p} switch. +@end table + +@geindex -gnat-p (gcc) + + +@table @asis + +@item @code{-gnat-p} + +Cancel effect of previous @emph{-gnatp} switch. +@end table + +@geindex -gnatP (gcc) -@item -gnatp -@cindex @option{-gnatp} (@command{gcc}) -Suppress all checks. See @ref{Run-Time Checks} for details. This switch -has no effect if cancelled by a subsequent @option{-gnat-p} switch. -@item -gnat-p -@cindex @option{-gnat-p} (@command{gcc}) -Cancel effect of previous @option{-gnatp} switch. +@table @asis + +@item @code{-gnatP} -@item -gnatP -@cindex @option{-gnatP} (@command{gcc}) Enable polling. This is required on some systems (notably Windows NT) to obtain asynchronous abort and asynchronous transfer of control capability. -@xref{Pragma Polling,,, gnat_rm, GNAT Reference Manual}, for full +See @cite{Pragma_Polling} in the @cite{GNAT_Reference_Manual} for full details. +@end table + +@geindex -gnatq (gcc) + + +@table @asis + +@item @code{-gnatq} -@item -gnatq -@cindex @option{-gnatq} (@command{gcc}) Don't quit. Try semantics, even if parse errors. +@end table + +@geindex -gnatQ (gcc) + + +@table @asis + +@item @code{-gnatQ} -@item -gnatQ -@cindex @option{-gnatQ} (@command{gcc}) -Don't quit. Generate @file{ALI} and tree files even if illegalities. +Don't quit. Generate @code{ALI} and tree files even if illegalities. Note that code generation is still suppressed in the presence of any -errors, so even with @option{-gnatQ} no object file is generated. +errors, so even with @emph{-gnatQ} no object file is generated. +@end table + +@geindex -gnatr (gcc) + + +@table @asis + +@item @code{-gnatr} -@item -gnatr -@cindex @option{-gnatr} (@command{gcc}) Treat pragma Restrictions as Restriction_Warnings. +@end table + +@geindex -gnatR (gcc) + + +@table @asis + +@item @code{-gnatR[0/1/2/3[s]]} -@item -gnatR@r{[}0@r{/}1@r{/}2@r{/}3@r{[}s@r{]]} -@cindex @option{-gnatR} (@command{gcc}) Output representation information for declared types and objects. -Note that this switch is not allowed if a previous @code{-gnatD} switch has +Note that this switch is not allowed if a previous @cite{-gnatD} switch has been given, since these two switches are not compatible. -@item -gnatRm[s] +@item @code{-gnatRm[s]} + Output convention and parameter passing mechanisms for all subprograms. +@end table + +@geindex -gnats (gcc) + + +@table @asis + +@item @code{-gnats} -@item -gnats -@cindex @option{-gnats} (@command{gcc}) Syntax check only. +@end table + +@geindex -gnatS (gcc) + + +@table @asis + +@item @code{-gnatS} -@item -gnatS -@cindex @option{-gnatS} (@command{gcc}) Print package Standard. +@end table + +@geindex -gnatt (gcc) + + +@table @asis + +@item @code{-gnatt} -@item -gnatt -@cindex @option{-gnatt} (@command{gcc}) Generate tree output file. +@end table + +@geindex -gnatT (gcc) + + +@table @asis + +@item @code{-gnatT@emph{nnn}} + +All compiler tables start at @cite{nnn} times usual starting size. +@end table + +@geindex -gnatu (gcc) + + +@table @asis -@item -gnatT@var{nnn} -@cindex @option{-gnatT} (@command{gcc}) -All compiler tables start at @var{nnn} times usual starting size. +@item @code{-gnatu} -@item -gnatu -@cindex @option{-gnatu} (@command{gcc}) List units for this compilation. +@end table -@item -gnatU -@cindex @option{-gnatU} (@command{gcc}) -Tag all error messages with the unique string ``error:'' +@geindex -gnatU (gcc) -@item -gnatv -@cindex @option{-gnatv} (@command{gcc}) -Verbose mode. Full error output with source lines to @file{stdout}. -@item -gnatV -@cindex @option{-gnatV} (@command{gcc}) -Control level of validity checking (@pxref{Validity Checking}). +@table @asis + +@item @code{-gnatU} + +Tag all error messages with the unique string 'error:' +@end table + +@geindex -gnatv (gcc) + + +@table @asis + +@item @code{-gnatv} + +Verbose mode. Full error output with source lines to @code{stdout}. +@end table + +@geindex -gnatV (gcc) + + +@table @asis + +@item @code{-gnatV} + +Control level of validity checking (@ref{fb,,Validity Checking}). +@end table + +@geindex -gnatw (gcc) + + +@table @asis + +@item @code{-gnatw@emph{xxx}} -@item -gnatw@var{xxx} -@cindex @option{-gnatw} (@command{gcc}) Warning mode where -@var{xxx} is a string of option letters that denotes +@cite{xxx} is a string of option letters that denotes the exact warnings that -are enabled or disabled (@pxref{Warning Message Control}). +are enabled or disabled (@ref{ff,,Warning Message Control}). +@end table + +@geindex -gnatW (gcc) + + +@table @asis + +@item @code{-gnatW@emph{e}} -@item -gnatW@var{e} -@cindex @option{-gnatW} (@command{gcc}) Wide character encoding method -(@var{e}=n/h/u/s/e/8). +(@cite{e}=n/h/u/s/e/8). +@end table + +@geindex -gnatx (gcc) + + +@table @asis + +@item @code{-gnatx} -@item -gnatx -@cindex @option{-gnatx} (@command{gcc}) Suppress generation of cross-reference information. +@end table + +@geindex -gnatX (gcc) + + +@table @asis + +@item @code{-gnatX} -@item -gnatX -@cindex @option{-gnatX} (@command{gcc}) Enable GNAT implementation extensions and latest Ada version. +@end table + +@geindex -gnaty (gcc) + + +@table @asis + +@item @code{-gnaty} + +Enable built-in style checks (@ref{100,,Style Checking}). +@end table + +@geindex -gnatz (gcc) + -@item -gnaty -@cindex @option{-gnaty} (@command{gcc}) -Enable built-in style checks (@pxref{Style Checking}). +@table @asis + +@item @code{-gnatz@emph{m}} -@item -gnatz@var{m} -@cindex @option{-gnatz} (@command{gcc}) Distribution stub generation and compilation -(@var{m}=r/c for receiver/caller stubs). +(@cite{m}=r/c for receiver/caller stubs). +@end table + +@geindex -I (gcc) + + +@table @asis + +@item @code{-I@emph{dir}} -@item -I@var{dir} -@cindex @option{-I} (@command{gcc}) -@cindex RTL -Direct GNAT to search the @var{dir} directory for source files needed by +@geindex RTL + +Direct GNAT to search the @cite{dir} directory for source files needed by the current compilation -(@pxref{Search Paths and the Run-Time Library (RTL)}). +(see @ref{8e,,Search Paths and the Run-Time Library (RTL)}). +@end table + +@geindex -I- (gcc) + + +@table @asis + +@item @code{-I-} + +@geindex RTL -@item -I- -@cindex @option{-I-} (@command{gcc}) -@cindex RTL Except for the source file named in the command line, do not look for source files in the directory containing the source file named in the command line -(@pxref{Search Paths and the Run-Time Library (RTL)}). - -@item -mbig-switch -@cindex @option{-mbig-switch} (@command{gcc}) -@cindex @code{case} statement (effect of @option{-mbig-switch} option) -This standard gcc switch causes the compiler to use larger offsets in its -jump table representation for @code{case} statements. -This may result in less efficient code, but is sometimes necessary -(for example on HP-UX targets) -@cindex HP-UX and @option{-mbig-switch} option -in order to compile large and/or nested @code{case} statements. - -@item -o @var{file} -@cindex @option{-o} (@command{gcc}) -This switch is used in @command{gcc} to redirect the generated object file +(see @ref{8e,,Search Paths and the Run-Time Library (RTL)}). +@end table + +@geindex -o (gcc) + + +@table @asis + +@item @code{-o @emph{file}} + +This switch is used in @emph{gcc} to redirect the generated object file and its associated ALI file. Beware of this switch with GNAT, because it may cause the object file and ALI file to have different names which in turn may confuse the binder and the linker. +@end table + +@geindex -nostdinc (gcc) + + +@table @asis + +@item @code{-nostdinc} -@item -nostdinc -@cindex @option{-nostdinc} (@command{gcc}) Inhibit the search of the default location for the GNAT Run Time Library (RTL) source files. +@end table + +@geindex -nostdlib (gcc) + + +@table @asis + +@item @code{-nostdlib} -@item -nostdlib -@cindex @option{-nostdlib} (@command{gcc}) Inhibit the search of the default location for the GNAT Run Time Library (RTL) ALI files. +@end table + +@geindex -O (gcc) -@c @item -O@ovar{n} -@c Expanding @ovar macro inline (explanation in macro def comments) -@item -O@r{[}@var{n}@r{]} -@cindex @option{-O} (@command{gcc}) -@var{n} controls the optimization level. @table @asis -@item n = 0 -No optimization, the default setting if no @option{-O} appears -@item n = 1 -Normal optimization, the default if you specify @option{-O} without -an operand. A good compromise between code quality and compilation +@item @code{-O[@emph{n}]} + +@cite{n} controls the optimization level: + + +@multitable {xxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item + +@emph{n} + +@tab + +Effect + +@item + +@emph{0} + +@tab + +No optimization, the default setting if no @emph{-O} appears + +@item + +@emph{1} + +@tab + +Normal optimization, the default if you specify @emph{-O} without an +operand. A good compromise between code quality and compilation time. -@item n = 2 -Extensive optimization, may improve execution time, possibly at the cost of -substantially increased compilation time. +@item + +@emph{2} + +@tab + +Extensive optimization, may improve execution time, possibly at +the cost of substantially increased compilation time. + +@item + +@emph{3} + +@tab + +Same as @emph{-O2}, and also includes inline expansion for small +subprograms in the same unit. + +@item + +@emph{s} -@item n = 3 -Same as @option{-O2}, and also includes inline expansion for small subprograms -in the same unit. +@tab -@item n = s Optimize space usage + +@end multitable + + +See also @ref{101,,Optimization Levels}. @end table -@noindent -See also @ref{Optimization Levels}. +@geindex -pass-exit-codes (gcc) + + +@table @asis +@item @code{-pass-exit-codes} -@item -pass-exit-codes -@cindex @option{-pass-exit-codes} (@command{gcc}) Catch exit codes from the compiler and use the most meaningful as exit status. +@end table + +@geindex --RTS (gcc) + + +@table @asis + +@item @code{--RTS=@emph{rts-path}} -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gcc}) Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). +equivalent @emph{gnatmake} flag (@ref{df,,Switches for gnatmake}). +@end table -@item -S -@cindex @option{-S} (@command{gcc}) -Used in place of @option{-c} to +@geindex -S (gcc) + + +@table @asis + +@item @code{-S} + +Used in place of @emph{-c} to cause the assembler source file to be -generated, using @file{.s} as the extension, +generated, using @code{.s} as the extension, instead of the object file. This may be useful if you need to examine the generated assembly code. +@end table + +@geindex -fverbose-asm (gcc) -@item -fverbose-asm -@cindex @option{-fverbose-asm} (@command{gcc}) -Used in conjunction with @option{-S} + +@table @asis + +@item @code{-fverbose-asm} + +Used in conjunction with @emph{-S} to cause the generated assembly code file to be annotated with variable names, making it significantly easier to follow. +@end table + +@geindex -v (gcc) + + +@table @asis + +@item @code{-v} -@item -v -@cindex @option{-v} (@command{gcc}) -Show commands generated by the @command{gcc} driver. Normally used only for +Show commands generated by the @emph{gcc} driver. Normally used only for debugging purposes or if you need to be sure what version of the compiler you are executing. +@end table + +@geindex -V (gcc) + + +@table @asis + +@item @code{-V @emph{ver}} -@item -V @var{ver} -@cindex @option{-V} (@command{gcc}) -Execute @var{ver} version of the compiler. This is the @command{gcc} +Execute @cite{ver} version of the compiler. This is the @emph{gcc} version, not the GNAT version. +@end table + +@geindex -w (gcc) + + +@table @asis + +@item @code{-w} -@item -w -@cindex @option{-w} (@command{gcc}) Turn off warnings generated by the back end of the compiler. Use of this switch also causes the default for front end warnings to be set -to suppress (as though @option{-gnatws} had appeared at the start of +to suppress (as though @emph{-gnatws} had appeared at the start of the options). - @end table -@c Combining qualifiers does not work on VMS +@geindex Combining GNAT switches + You may combine a sequence of GNAT switches into a single switch. For example, the combined switch -@cindex Combining GNAT switches -@smallexample +@quotation + +@example -gnatofi3 -@end smallexample +@end example +@end quotation -@noindent is equivalent to specifying the following sequence of switches: -@smallexample +@quotation + +@example -gnato -gnatf -gnati3 -@end smallexample +@end example +@end quotation -@noindent The following restrictions apply to the combination of switches in this manner: -@itemize @bullet -@item -The switch @option{-gnatc} if combined with other switches must come + +@itemize * + +@item +The switch @emph{-gnatc} if combined with other switches must come first in the string. -@item -The switch @option{-gnats} if combined with other switches must come +@item +The switch @emph{-gnats} if combined with other switches must come first in the string. -@item +@item The switches - -@option{-gnatzc} and @option{-gnatzr} may not be combined with any other +@emph{-gnatzc} and @emph{-gnatzr} may not be combined with any other switches, and only one of them may appear in the command line. -@item -The switch @option{-gnat-p} may not be combined with any other switch. +@item +The switch @emph{-gnat-p} may not be combined with any other switch. -@item -Once a ``y'' appears in the string (that is a use of the @option{-gnaty} +@item +Once a 'y' appears in the string (that is a use of the @emph{-gnaty} switch), then all further characters in the switch are interpreted -as style modifiers (see description of @option{-gnaty}). +as style modifiers (see description of @emph{-gnaty}). -@item -Once a ``d'' appears in the string (that is a use of the @option{-gnatd} +@item +Once a 'd' appears in the string (that is a use of the @emph{-gnatd} switch), then all further characters in the switch are interpreted -as debug flags (see description of @option{-gnatd}). +as debug flags (see description of @emph{-gnatd}). -@item -Once a ``w'' appears in the string (that is a use of the @option{-gnatw} +@item +Once a 'w' appears in the string (that is a use of the @emph{-gnatw} switch), then all further characters in the switch are interpreted -as warning mode modifiers (see description of @option{-gnatw}). +as warning mode modifiers (see description of @emph{-gnatw}). -@item -Once a ``V'' appears in the string (that is a use of the @option{-gnatV} +@item +Once a 'V' appears in the string (that is a use of the @emph{-gnatV} switch), then all further characters in the switch are interpreted -as validity checking options (@pxref{Validity Checking}). +as validity checking options (@ref{fb,,Validity Checking}). -@item -Option ``em'', ``ec'', ``ep'', ``l='' and ``R'' must be the last options in +@item +Option 'em', 'ec', 'ep', 'l=' and 'R' must be the last options in a combined list of options. @end itemize -@node Output and Error Message Control +@node Output and Error Message Control,Warning Message Control,Alphabetical List of All Switches,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat id14}@anchor{102}@anchor{gnat_ugn/building_executable_programs_with_gnat output-and-error-message-control}@anchor{103} @subsection Output and Error Message Control -@findex stderr -@noindent -The standard default format for error messages is called ``brief format''. -Brief format messages are written to @file{stderr} (the standard error + +@geindex stderr + +The standard default format for error messages is called 'brief format'. +Brief format messages are written to @code{stderr} (the standard error file) and have the following form: -@smallexample +@example e.adb:3:04: Incorrect spelling of keyword "function" e.adb:4:20: ";" should be "is" -@end smallexample +@end example -@noindent The first integer after the file name is the line number in the file, and the second integer is the column number within the line. -@code{GPS} can parse the error messages +@cite{GPS} can parse the error messages and point to the referenced character. The following switches provide control over the error message format: -@table @option -@c !sort! -@item -gnatv -@cindex @option{-gnatv} (@command{gcc}) -@findex stdout -The v stands for verbose. +@geindex -gnatv (gcc) + + +@table @asis + +@item @code{-gnatv} + +The @cite{v} stands for verbose. The effect of this setting is to write long-format error -messages to @file{stdout} (the standard output file. +messages to @code{stdout} (the standard output file. The same program compiled with the -@option{-gnatv} switch would generate: +@emph{-gnatv} switch would generate: -@smallexample -@cartouche +@example 3. funcion X (Q : Integer) | >>> Incorrect spelling of keyword "function" 4. return Integer; | >>> ";" should be "is" -@end cartouche -@end smallexample +@end example -@noindent -The vertical bar indicates the location of the error, and the @samp{>>>} +The vertical bar indicates the location of the error, and the @code{>>>} prefix can be used to search for error messages. When this switch is used the only source lines output are those with errors. +@end table + +@geindex -gnatl (gcc) + -@item -gnatl -@cindex @option{-gnatl} (@command{gcc}) -The @code{l} stands for list. +@table @asis + +@item @code{-gnatl} + +The @cite{l} stands for list. This switch causes a full listing of the file to be generated. In the case where a body is compiled, the corresponding spec is also listed, along with any subunits. Typical output from compiling a package -body @file{p.adb} might look like: +body @code{p.adb} might look like: -@smallexample @c ada -@cartouche - Compiling: p.adb +@example +Compiling: p.adb - 1. @b{package} @b{body} p @b{is} - 2. @b{procedure} a; - 3. @b{procedure} a @b{is} @b{separate}; - 4. @b{begin} - 5. @b{null} + 1. package body p is + 2. procedure a; + 3. procedure a is separate; + 4. begin + 5. null | >>> missing ";" - 6. @b{end}; + 6. end; Compiling: p.ads - 1. @b{package} p @b{is} - 2. @b{pragma} Elaborate_Body + 1. package p is + 2. pragma Elaborate_Body | >>> missing ";" - 3. @b{end} p; + 3. end p; Compiling: p-a.adb - 1. @b{separate} p + 1. separate p | >>> missing "(" - 2. @b{procedure} a @b{is} - 3. @b{begin} - 4. @b{null} + 2. procedure a is + 3. begin + 4. null | >>> missing ";" - 5. @b{end}; -@end cartouche -@end smallexample + 5. end; +@end example -@noindent -@findex stderr -When you specify the @option{-gnatv} or @option{-gnatl} switches and +When you specify the @emph{-gnatv} or @emph{-gnatl} switches and standard output is redirected, a brief summary is written to -@file{stderr} (standard error) giving the number of error messages and +@code{stderr} (standard error) giving the number of error messages and warning messages generated. +@end table + +@geindex -gnatl=fname (gcc) + -@item -gnatl=file -@cindex @option{-gnatl=fname} (@command{gcc}) -This has the same effect as @option{-gnatl} except that the output is +@table @asis + +@item @code{-gnatl=@emph{fname}} + +This has the same effect as @emph{-gnatl} except that the output is written to a file instead of to standard output. If the given name -@file{fname} does not start with a period, then it is the full name -of the file to be written. If @file{fname} is an extension, it is +@code{fname} does not start with a period, then it is the full name +of the file to be written. If @code{fname} is an extension, it is appended to the name of the file being compiled. For example, if -file @file{xyz.adb} is compiled with @option{-gnatl=.lst}, +file @code{xyz.adb} is compiled with @emph{-gnatl=.lst}, then the output is written to file xyz.adb.lst. +@end table + +@geindex -gnatU (gcc) + + +@table @asis + +@item @code{-gnatU} -@item -gnatU -@cindex @option{-gnatU} (@command{gcc}) This switch forces all error messages to be preceded by the unique -string ``error:''. This means that error messages take a few more +string 'error:'. This means that error messages take a few more characters in space, but allows easy searching for and identification of error messages. +@end table + +@geindex -gnatb (gcc) + -@item -gnatb -@cindex @option{-gnatb} (@command{gcc}) -The @code{b} stands for brief. +@table @asis + +@item @code{-gnatb} + +The @cite{b} stands for brief. This switch causes GNAT to generate the -brief format error messages to @file{stderr} (the standard error +brief format error messages to @code{stderr} (the standard error file) as well as the verbose format message or full listing (which as usual is written to -@file{stdout} (the standard output file). +@code{stdout} (the standard output file). +@end table + +@geindex -gnatm (gcc) + + +@table @asis -@item -gnatm=@var{n} -@cindex @option{-gnatm} (@command{gcc}) -The @code{m} stands for maximum. -@var{n} is a decimal integer in the +@item @code{-gnatm=@emph{n}} + +The @cite{m} stands for maximum. +@cite{n} is a decimal integer in the range of 1 to 999999 and limits the number of error or warning messages to be generated. For example, using -@option{-gnatm2} might yield +@emph{-gnatm2} might yield -@smallexample +@example e.adb:3:04: Incorrect spelling of keyword "function" e.adb:5:35: missing ".." fatal error: maximum number of errors detected compilation abandoned -@end smallexample +@end example -@noindent The default setting if no switch is given is 9999. If the number of warnings reaches this limit, then a message is output and further warnings are suppressed, @@ -4519,66 +10320,88 @@ but the compilation is continued. If the number of error messages reaches this limit, then a message is output and the compilation is abandoned. A value of zero means that no limit applies. -@noindent Note that the equal sign is optional, so the switches -@option{-gnatm2} and @option{-gnatm=2} are equivalent. +@emph{-gnatm2} and @emph{-gnatm=2} are equivalent. +@end table + +@geindex -gnatf (gcc) + + +@table @asis + +@item @code{-gnatf} + +@geindex Error messages +@geindex suppressing -@item -gnatf -@cindex @option{-gnatf} (@command{gcc}) -@cindex Error messages, suppressing -The @code{f} stands for full. +The @cite{f} stands for full. Normally, the compiler suppresses error messages that are likely to be redundant. This switch causes all error messages to be generated. In particular, in the case of references to undefined variables. If a given variable is referenced several times, the normal format of messages is -@smallexample + +@example e.adb:7:07: "V" is undefined (more references follow) -@end smallexample +@end example -@noindent where the parenthetical comment warns that there are additional -references to the variable @code{V}. Compiling the same program with the -@option{-gnatf} switch yields +references to the variable @cite{V}. Compiling the same program with the +@emph{-gnatf} switch yields -@smallexample +@example e.adb:7:07: "V" is undefined e.adb:8:07: "V" is undefined e.adb:8:12: "V" is undefined e.adb:8:16: "V" is undefined e.adb:9:07: "V" is undefined e.adb:9:12: "V" is undefined -@end smallexample +@end example -@noindent -The @option{-gnatf} switch also generates additional information for +The @emph{-gnatf} switch also generates additional information for some error messages. Some examples are: -@itemize @bullet -@item + +@itemize * + +@item Details on possibly non-portable unchecked conversion -@item + +@item List possible interpretations for ambiguous calls -@item + +@item Additional details on incorrect parameters @end itemize +@end table + +@geindex -gnatjnn (gcc) + + +@table @asis + +@item @code{-gnatjnn} -@item -gnatjnn -@cindex @option{-gnatjnn} (@command{gcc}) -In normal operation mode (or if @option{-gnatj0} is used), then error messages +In normal operation mode (or if @emph{-gnatj0} is used), then error messages with continuation lines are treated as though the continuation lines were separate messages (and so a warning with two continuation lines counts as three warnings, and is listed as three separate messages). -If the @option{-gnatjnn} switch is used with a positive value for nn, then +If the @emph{-gnatjnn} switch is used with a positive value for nn, then messages are output in a different manner. A message and all its continuation lines are treated as a unit, and count as only one warning or message in the statistics totals. Furthermore, the message is reformatted so that no line is longer than nn characters. +@end table + +@geindex -gnatq (gcc) -@item -gnatq -@cindex @option{-gnatq} (@command{gcc}) -The @code{q} stands for quit (really ``don't quit''). + +@table @asis + +@item @code{-gnatq} + +The @cite{q} stands for quit (really 'don't quit'). In normal operation mode, the compiler first parses the program and determines if there are any syntax errors. If there are, appropriate error messages are generated and compilation is immediately terminated. @@ -4587,40 +10410,48 @@ GNAT to continue with semantic analysis even if syntax errors have been found. This may enable the detection of more errors in a single run. On the other hand, the semantic analyzer is more likely to encounter some internal fatal error when given a syntactically invalid tree. +@end table + +@geindex -gnatQ (gcc) + + +@table @asis + +@item @code{-gnatQ} -@item -gnatQ -@cindex @option{-gnatQ} (@command{gcc}) -In normal operation mode, the @file{ALI} file is not generated if any -illegalities are detected in the program. The use of @option{-gnatQ} forces -generation of the @file{ALI} file. This file is marked as being in +In normal operation mode, the @code{ALI} file is not generated if any +illegalities are detected in the program. The use of @emph{-gnatQ} forces +generation of the @code{ALI} file. This file is marked as being in error, so it cannot be used for binding purposes, but it does contain reasonably complete cross-reference information, and thus may be useful for use by tools (e.g., semantic browsing tools or integrated development -environments) that are driven from the @file{ALI} file. This switch -implies @option{-gnatq}, since the semantic phase must be run to get a +environments) that are driven from the @code{ALI} file. This switch +implies @emph{-gnatq}, since the semantic phase must be run to get a meaningful ALI file. -In addition, if @option{-gnatt} is also specified, then the tree file is +In addition, if @emph{-gnatt} is also specified, then the tree file is generated even if there are illegalities. It may be useful in this case -to also specify @option{-gnatq} to ensure that full semantic processing +to also specify @emph{-gnatq} to ensure that full semantic processing occurs. The resulting tree file can be processed by ASIS, for the purpose of providing partial information about illegal units, but if the error causes the tree to be badly malformed, then ASIS may crash during the analysis. -When @option{-gnatQ} is used and the generated @file{ALI} file is marked as -being in error, @command{gnatmake} will attempt to recompile the source when it -finds such an @file{ALI} file, including with switch @option{-gnatc}. - -Note that @option{-gnatQ} has no effect if @option{-gnats} is specified, -since ALI files are never generated if @option{-gnats} is set. +When @emph{-gnatQ} is used and the generated @code{ALI} file is marked as +being in error, @emph{gnatmake} will attempt to recompile the source when it +finds such an @code{ALI} file, including with switch @emph{-gnatc}. +Note that @emph{-gnatQ} has no effect if @emph{-gnats} is specified, +since ALI files are never generated if @emph{-gnats} is set. @end table -@node Warning Message Control +@node Warning Message Control,Debugging and Assertion Control,Output and Error Message Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat warning-message-control}@anchor{ff}@anchor{gnat_ugn/building_executable_programs_with_gnat id15}@anchor{104} @subsection Warning Message Control -@cindex Warning messages -@noindent + + +@geindex Warning messages + In addition to error messages, which correspond to illegalities as defined in the Ada Reference Manual, the compiler detects two kinds of warning situations. @@ -4630,242 +10461,310 @@ warning message to alert you to a possible error. Second, if the compiler detects a situation that is sure to raise an exception at run time, it generates a warning message. The following shows an example of warning messages: -@smallexample + +@example e.adb:4:24: warning: creation of object may raise Storage_Error e.adb:10:17: warning: static value out of range e.adb:10:17: warning: "Constraint_Error" will be raised at run time -@end smallexample +@end example -@noindent GNAT considers a large number of situations as appropriate for the generation of warning messages. As always, warnings are not definite indications of errors. For example, if you do an out-of-range assignment with the deliberate intention of raising a -@code{Constraint_Error} exception, then the warning that may be +@cite{Constraint_Error} exception, then the warning that may be issued does not indicate an error. Some of the situations for which GNAT issues warnings (at least some of the time) are given in the following list. This list is not complete, and new warnings are often added to subsequent versions of GNAT. The list is intended to give a general idea of the kinds of warnings that are generated. -@itemize @bullet -@item + +@itemize * + +@item Possible infinitely recursive calls -@item +@item Out-of-range values being assigned -@item +@item Possible order of elaboration problems -@item +@item Size not a multiple of alignment for a record type -@item +@item Assertions (pragma Assert) that are sure to fail -@item +@item Unreachable code -@item +@item Address clauses with possibly unaligned values, or where an attempt is made to overlay a smaller variable with a larger one. -@item +@item Fixed-point type declarations with a null range -@item +@item Direct_IO or Sequential_IO instantiated with a type that has access values -@item +@item Variables that are never assigned a value -@item +@item Variables that are referenced before being initialized -@item -Task entries with no corresponding @code{accept} statement +@item +Task entries with no corresponding @cite{accept} statement -@item -Duplicate accepts for the same task entry in a @code{select} +@item +Duplicate accepts for the same task entry in a @cite{select} -@item +@item Objects that take too much storage -@item +@item Unchecked conversion between types of differing sizes -@item -Missing @code{return} statement along some execution path in a function +@item +Missing @cite{return} statement along some execution path in a function -@item +@item Incorrect (unrecognized) pragmas -@item +@item Incorrect external names -@item +@item Allocation from empty storage pool -@item +@item Potentially blocking operation in protected type -@item +@item Suspicious parenthesization of expressions -@item +@item Mismatching bounds in an aggregate -@item +@item Attempt to return local value by reference -@item +@item Premature instantiation of a generic body -@item +@item Attempt to pack aliased components -@item +@item Out of bounds array subscripts -@item +@item Wrong length on string assignment -@item +@item Violations of style rules if style checking is enabled -@item -Unused @code{with} clauses +@item +Unused @emph{with} clauses -@item -@code{Bit_Order} usage that does not have any effect +@item +@cite{Bit_Order} usage that does not have any effect -@item -@code{Standard.Duration} used to resolve universal fixed expression +@item +@cite{Standard.Duration} used to resolve universal fixed expression -@item +@item Dereference of possibly null value -@item +@item Declaration that is likely to cause storage error -@item -Internal GNAT unit @code{with}'ed by application unit +@item +Internal GNAT unit @emph{with}ed by application unit -@item +@item Values known to be out of range at compile time -@item +@item Unreferenced or unmodified variables. Note that a special exemption applies to variables which contain any of the substrings -@code{DISCARD, DUMMY, IGNORE, JUNK, UNUSED}, in any casing. Such variables +@cite{DISCARD@comma{} DUMMY@comma{} IGNORE@comma{} JUNK@comma{} UNUSED}, in any casing. Such variables are considered likely to be intentionally used in a situation where otherwise a warning would be given, so warnings of this kind are always suppressed for such variables. -@item +@item Address overlays that could clobber memory -@item +@item Unexpected initialization when address clause present -@item +@item Bad alignment for address clause -@item +@item Useless type conversions -@item +@item Redundant assignment statements and other redundant constructs -@item +@item Useless exception handlers -@item +@item Accidental hiding of name by child unit -@item +@item Access before elaboration detected at compile time -@item -A range in a @code{for} loop that is known to be null or might be null - +@item +A range in a @cite{for} loop that is known to be null or might be null @end itemize -@noindent The following section lists compiler switches that are available to control the handling of warning messages. It is also possible to exercise much finer control over what warnings are issued and -suppressed using the GNAT pragma Warnings, @xref{Pragma Warnings,,, -gnat_rm, GNAT Reference manual}. +suppressed using the GNAT pragma Warnings (see the description +of the pragma in the @cite{GNAT_Reference_manual}). + +@geindex -gnatwa (gcc) + + +@table @asis + +@item @code{-gnatwa} -@table @option -@c !sort! -@item -gnatwa @emph{Activate most optional warnings.} -@cindex @option{-gnatwa} (@command{gcc}) + This switch activates most optional warning messages. See the remaining list in this section for details on optional warning messages that can be individually controlled. The warnings that are not turned on by this switch are: -@itemize -@item @option{-gnatwd} (implicit dereferencing) -@item @option{-gnatw.d} (tag warnings with -gnatw switch) -@item @option{-gnatwh} (hiding) -@item @option{-gnatw.h} (holes in record layouts) -@item @option{-gnatw.k} (redefinition of names in standard) -@item @option{-gnatwl} (elaboration warnings) -@item @option{-gnatw.l} (inherited aspects) -@item @option{-gnatw.n} (atomic synchronization) -@item @option{-gnatwo} (address clause overlay) -@item @option{-gnatw.o} (values set by out parameters ignored) -@item @option{-gnatw.s} (overridden size clause) -@item @option{-gnatwt} (tracking of deleted conditional code) -@item @option{-gnatw.u} (unordered enumeration) -@item @option{-gnatw.w} (use of Warnings Off) -@item @option{-gnatw.y} (reasons for package needing body) + +@itemize * + +@item +@code{-gnatwd} (implicit dereferencing) + +@item +@code{-gnatw.d} (tag warnings with -gnatw switch) + +@item +@code{-gnatwh} (hiding) + +@item +@code{-gnatw.h} (holes in record layouts) + +@item +@code{-gnatw.k} (redefinition of names in standard) + +@item +@code{-gnatwl} (elaboration warnings) + +@item +@code{-gnatw.l} (inherited aspects) + +@item +@code{-gnatw.n} (atomic synchronization) + +@item +@code{-gnatwo} (address clause overlay) + +@item +@code{-gnatw.o} (values set by out parameters ignored) + +@item +@code{-gnatw.s} (overridden size clause) + +@item +@code{-gnatwt} (tracking of deleted conditional code) + +@item +@code{-gnatw.u} (unordered enumeration) + +@item +@code{-gnatw.w} (use of Warnings Off) + +@item +@code{-gnatw.y} (reasons for package needing body) @end itemize All other optional warnings are turned on. +@end table + +@geindex -gnatwA (gcc) + + +@table @asis + +@item @code{-gnatwA} -@item -gnatwA @emph{Suppress all optional errors.} -@cindex @option{-gnatwA} (@command{gcc}) + This switch suppresses all optional warning messages, see remaining list in this section for details on optional warning messages that can be -individually controlled. Note that unlike switch @option{-gnatws}, the -use of switch @option{-gnatwA} does not suppress warnings that are +individually controlled. Note that unlike switch @emph{-gnatws}, the +use of switch @emph{-gnatwA} does not suppress warnings that are normally given unconditionally and cannot be individually controlled (for example, the warning about a missing exit path in a function). -Also, again unlike switch @option{-gnatws}, warnings suppressed by -the use of switch @option{-gnatwA} can be individually turned back -on. For example the use of switch @option{-gnatwA} followed by -switch @option{-gnatwd} will suppress all optional warnings except +Also, again unlike switch @emph{-gnatws}, warnings suppressed by +the use of switch @emph{-gnatwA} can be individually turned back +on. For example the use of switch @emph{-gnatwA} followed by +switch @emph{-gnatwd} will suppress all optional warnings except the warnings for implicit dereferencing. +@end table + +@geindex -gnatw.a (gcc) + + +@table @asis + +@item @code{-gnatw.a} -@item -gnatw.a @emph{Activate warnings on failing assertions.} -@cindex @option{-gnatw.a} (@command{gcc}) -@cindex Assert failures + +@geindex Assert failures + This switch activates warnings for assertions where the compiler can tell at compile time that the assertion will fail. Note that this warning is given even if assertions are disabled. The default is that such warnings are generated. +@end table + +@geindex -gnatw.A (gcc) + + +@table @asis + +@item @code{-gnatw.A} -@item -gnatw.A @emph{Suppress warnings on failing assertions.} -@cindex @option{-gnatw.A} (@command{gcc}) -@cindex Assert failures + +@geindex Assert failures + This switch suppresses warnings for assertions where the compiler can tell at compile time that the assertion will fail. +@end table + +@geindex -gnatwb (gcc) + + +@table @asis + +@item @code{-gnatwb} -@item -gnatwb @emph{Activate warnings on bad fixed values.} -@cindex @option{-gnatwb} (@command{gcc}) -@cindex Bad fixed values -@cindex Fixed-point Small value -@cindex Small value + +@geindex Bad fixed values + +@geindex Fixed-point Small value + +@geindex Small value + This switch activates warnings for static fixed-point expressions whose value is not an exact multiple of Small. Such values are implementation dependent, since an implementation is free to choose either of the multiples @@ -4873,32 +10772,63 @@ that surround the value. GNAT always chooses the closer one, but this is not required behavior, and it is better to specify a value that is an exact multiple, ensuring predictable execution. The default is that such warnings are not generated. +@end table + +@geindex -gnatwB (gcc) + + +@table @asis + +@item @code{-gnatwB} -@item -gnatwB @emph{Suppress warnings on bad fixed values.} -@cindex @option{-gnatwB} (@command{gcc}) + This switch suppresses warnings for static fixed-point expressions whose value is not an exact multiple of Small. +@end table + +@geindex -gnatw.b (gcc) + + +@table @asis + +@item @code{-gnatw.b} -@item -gnatw.b @emph{Activate warnings on biased representation.} -@cindex @option{-gnatw.b} (@command{gcc}) -@cindex Biased representation + +@geindex Biased representation + This switch activates warnings when a size clause, value size clause, component clause, or component size clause forces the use of biased representation for an integer type (e.g. representing a range of 10..11 in a single bit by using 0/1 to represent 10/11). The default is that such warnings are generated. +@end table + +@geindex -gnatwB (gcc) + + +@table @asis + +@item @code{-gnatw.B} -@item -gnatw.B @emph{Suppress warnings on biased representation.} -@cindex @option{-gnatwB} (@command{gcc}) + This switch suppresses warnings for representation clauses that force the use of biased representation. +@end table + +@geindex -gnatwc (gcc) + + +@table @asis + +@item @code{-gnatwc} -@item -gnatwc @emph{Activate warnings on conditionals.} -@cindex @option{-gnatwc} (@command{gcc}) -@cindex Conditionals, constant + +@geindex Conditionals +@geindex constant + This switch activates warnings for conditional expressions used in tests that are known to be True or False at compile time. The default is that such warnings are not generated. @@ -4909,11 +10839,11 @@ for conditional compilation in Ada, and this would generate too many false positive warnings. This warning option also activates a special test for comparisons using -the operators ``>='' and`` <=''. +the operators '>=' and' <='. If the compiler can tell that only the equality condition is possible, -then it will warn that the ``>'' or ``<'' part of the test -is useless and that the operator could be replaced by ``=''. -An example would be comparing a @code{Natural} variable <= 0. +then it will warn that the '>' or '<' part of the test +is useless and that the operator could be replaced by '='. +An example would be comparing a @cite{Natural} variable <= 0. This warning option also generates warnings if one or both tests is optimized away in a membership test for integer @@ -4921,95 +10851,167 @@ values if the result can be determined at compile time. Range tests on enumeration types are not included, since it is common for such tests to include an end point. -This warning can also be turned on using @option{-gnatwa}. +This warning can also be turned on using @emph{-gnatwa}. +@end table + +@geindex -gnatwC (gcc) + + +@table @asis + +@item @code{-gnatwC} -@item -gnatwC @emph{Suppress warnings on conditionals.} -@cindex @option{-gnatwC} (@command{gcc}) + This switch suppresses warnings for conditional expressions used in tests that are known to be True or False at compile time. +@end table + +@geindex -gnatw.c (gcc) + + +@table @asis + +@item @code{-gnatw.c} -@item -gnatw.c @emph{Activate warnings on missing component clauses.} -@cindex @option{-gnatw.c} (@command{gcc}) -@cindex Component clause, missing + +@geindex Component clause +@geindex missing + This switch activates warnings for record components where a record representation clause is present and has component clauses for the majority, but not all, of the components. A warning is given for each component for which no component clause is present. +@end table + +@geindex -gnatwC (gcc) + + +@table @asis + +@item @code{-gnatw.C} -@item -gnatw.C @emph{Suppress warnings on missing component clauses.} -@cindex @option{-gnatwC} (@command{gcc}) + This switch suppresses warnings for record components that are missing a component clause in the situation described above. +@end table + +@geindex -gnatwd (gcc) + + +@table @asis + +@item @code{-gnatwd} -@item -gnatwd @emph{Activate warnings on implicit dereferencing.} -@cindex @option{-gnatwd} (@command{gcc}) + If this switch is set, then the use of a prefix of an access type in an indexed component, slice, or selected component without an -explicit @code{.all} will generate a warning. With this warning +explicit @cite{.all} will generate a warning. With this warning enabled, access checks occur only at points where an explicit -@code{.all} appears in the source code (assuming no warnings are +@cite{.all} appears in the source code (assuming no warnings are generated as a result of this switch). The default is that such warnings are not generated. +@end table + +@geindex -gnatwD (gcc) + + +@table @asis + +@item @code{-gnatwD} -@item -gnatwD @emph{Suppress warnings on implicit dereferencing.} -@cindex @option{-gnatwD} (@command{gcc}) -@cindex Implicit dereferencing -@cindex Dereferencing, implicit + +@geindex Implicit dereferencing + +@geindex Dereferencing +@geindex implicit + This switch suppresses warnings for implicit dereferences in indexed components, slices, and selected components. +@end table + +@geindex -gnatw.d (gcc) + + +@table @asis + +@item @code{-gnatw.d} -@item -gnatw.d @emph{Activate tagging of warning and info messages.} -@cindex @option{-gnatw.d} (@command{gcc}) + If this switch is set, then warning messages are tagged, with one of the following strings: -@table @option +@quotation + -@item [-gnatw?] -Used to tag warnings controlled by the switch @option{-gnatwx} where x +@itemize - + +@item +@emph{[-gnatw?]} +Used to tag warnings controlled by the switch @emph{-gnatwx} where x is a letter a-z. -@item [-gnatw.?] -Used to tag warnings controlled by the switch @option{-gnatw.x} where x +@item +@emph{[-gnatw.?]} +Used to tag warnings controlled by the switch @emph{-gnatw.x} where x is a letter a-z. -@item [-gnatel] +@item +@emph{[-gnatel]} Used to tag elaboration information (info) messages generated when the -static model of elaboration is used and the @option{-gnatel} switch is set. +static model of elaboration is used and the @emph{-gnatel} switch is set. -@item [restriction warning] +@item +@emph{[restriction warning]} Used to tag warning messages for restriction violations, activated by use -of the pragma @option{Restriction_Warnings}. +of the pragma @emph{Restriction_Warnings}. -@item [warning-as-error] +@item +@emph{[warning-as-error]} Used to tag warning messages that have been converted to error messages by use of the pragma Warning_As_Error. Note that such warnings are prefixed by the string "error: " rather than "warning: ". -@item [enabled by default] +@item +@emph{[enabled by default]} Used to tag all other warnings that are always given by default, unless -warnings are completely suppressed using pragma @option{Warnings(Off)} or -the switch @option{-gnatws}. - +warnings are completely suppressed using pragma @emph{Warnings(Off)} or +the switch @emph{-gnatws}. +@end itemize +@end quotation @end table -@item -gnatw.D +@geindex -gnatw.d (gcc) + + +@table @asis + +@item @code{-gnatw.D} + @emph{Deactivate tagging of warning and info messages messages.} -@cindex @option{-gnatw.d} (@command{gcc}) + If this switch is set, then warning messages return to the default mode in which warnings and info messages are not tagged as described above for -@code{-gnatw.d}. +@cite{-gnatw.d}. +@end table + +@geindex -gnatwe (gcc) + +@geindex Warnings +@geindex treat as error + + +@table @asis + +@item @code{-gnatwe} -@item -gnatwe @emph{Treat warnings and style checks as errors.} -@cindex @option{-gnatwe} (@command{gcc}) -@cindex Warnings, treat as error + This switch causes warning messages and style check messages to be treated as errors. The warning string still appears, but the warning messages are counted @@ -5017,247 +11019,422 @@ as errors, and prevent the generation of an object file. Note that this is the only -gnatw switch that affects the handling of style check messages. Note also that this switch has no effect on info (information) messages, which are not treated as errors if this switch is present. +@end table + +@geindex -gnatw.e (gcc) + + +@table @asis + +@item @code{-gnatw.e} -@item -gnatw.e @emph{Activate every optional warning} -@cindex @option{-gnatw.e} (@command{gcc}) -@cindex Warnings, activate every optional warning + +@geindex Warnings +@geindex activate every optional warning + This switch activates all optional warnings, including those which -are not activated by @code{-gnatwa}. The use of this switch is not +are not activated by @cite{-gnatwa}. The use of this switch is not recommended for normal use. If you turn this switch on, it is almost certain that you will get large numbers of useless warnings. The -warnings that are excluded from @code{-gnatwa} are typically highly +warnings that are excluded from @cite{-gnatwa} are typically highly specialized warnings that are suitable for use only in code that has been specifically designed according to specialized coding rules. +@end table + +@geindex -gnatwf (gcc) + + +@table @asis + +@item @code{-gnatwf} -@item -gnatwf @emph{Activate warnings on unreferenced formals.} -@cindex @option{-gnatwf} (@command{gcc}) -@cindex Formals, unreferenced + +@geindex Formals +@geindex unreferenced + This switch causes a warning to be generated if a formal parameter is not referenced in the body of the subprogram. This warning can -also be turned on using @option{-gnatwu}. The +also be turned on using @emph{-gnatwu}. The default is that these warnings are not generated. +@end table + +@geindex -gnatwF (gcc) + + +@table @asis + +@item @code{-gnatwF} -@item -gnatwF @emph{Suppress warnings on unreferenced formals.} -@cindex @option{-gnatwF} (@command{gcc}) + This switch suppresses warnings for unreferenced formal parameters. Note that the -combination @option{-gnatwu} followed by @option{-gnatwF} has the +combination @emph{-gnatwu} followed by @emph{-gnatwF} has the effect of warning on unreferenced entities other than subprogram formals. +@end table -@item -gnatw.f -@emph{Activate warnings on suspicious subprogram 'Access.} -@cindex @option{-gnatw.f} (@command{gcc}) -This switch causes a warning to be generated if @code{P'Access} occurs -in the same package where subprogram P is declared, and the -@code{P'Access} is evaluated at elaboration time, and occurs before -the body of P has been elaborated. For example, if we have -@code{X : T := P'Access;}, then if X.all is subsequently called before -the body of P is elaborated, it could cause -access-before-elaboration. The default is that these warnings are not -generated. +@geindex -gnatwg (gcc) + + +@table @asis -@item -gnatw.F -@emph{Suppress warnings on suspicious subprogram 'Access.} -@cindex @option{-gnatw.F} (@command{gcc}) -This switch suppresses warnings for suspicious subprogram 'Access. +@item @code{-gnatwg} -@item -gnatwg @emph{Activate warnings on unrecognized pragmas.} -@cindex @option{-gnatwg} (@command{gcc}) -@cindex Pragmas, unrecognized + +@geindex Pragmas +@geindex unrecognized + This switch causes a warning to be generated if an unrecognized pragma is encountered. Apart from issuing this warning, the pragma is ignored and has no effect. The default is that such warnings are issued (satisfying the Ada Reference Manual requirement that such warnings appear). +@end table + +@geindex -gnatwG (gcc) + + +@table @asis + +@item @code{-gnatwG} -@item -gnatwG @emph{Suppress warnings on unrecognized pragmas.} -@cindex @option{-gnatwG} (@command{gcc}) + This switch suppresses warnings for unrecognized pragmas. +@end table + +@geindex -gnatw.g (gcc) + + +@table @asis + +@item @code{-gnatw.g} -@item -gnatw.g @emph{Warnings used for GNAT sources} -@cindex @option{-gnatw.g} (@command{gcc}) + This switch sets the warning categories that are used by the standard GNAT style. Currently this is equivalent to -@option{-gnatwAao.sI.C.V.X} +@emph{-gnatwAao.sI.C.V.X} but more warnings may be added in the future without advanced notice. +@end table + +@geindex -gnatwh (gcc) + + +@table @asis + +@item @code{-gnatwh} -@item -gnatwh @emph{Activate warnings on hiding.} -@cindex @option{-gnatwh} (@command{gcc}) -@cindex Hiding of Declarations + +@geindex Hiding of Declarations + This switch activates warnings on hiding declarations. A declaration is considered hiding if it is for a non-overloadable entity, and it declares an entity with the same name as some other entity that is directly or use-visible. The default is that such warnings are not generated. +@end table + +@geindex -gnatwH (gcc) + + +@table @asis + +@item @code{-gnatwH} -@item -gnatwH @emph{Suppress warnings on hiding.} -@cindex @option{-gnatwH} (@command{gcc}) + This switch suppresses warnings on hiding declarations. +@end table + +@geindex -gnatw.h (gcc) + + +@table @asis + +@item @code{-gnatw.h} -@item -gnatw.h @emph{Activate warnings on holes/gaps in records.} -@cindex @option{-gnatw.h} (@command{gcc}) -@cindex Record Representation (gaps) + +@geindex Record Representation (gaps) + This switch activates warnings on component clauses in record representation clauses that leave holes (gaps) in the record layout. If this warning option is active, then record representation clauses should specify a contiguous layout, adding unused fill fields if needed. +@end table + +@geindex -gnatw.H (gcc) + + +@table @asis + +@item @code{-gnatw.H} -@item -gnatw.H @emph{Suppress warnings on holes/gaps in records.} -@cindex @option{-gnatw.H} (@command{gcc}) + This switch suppresses warnings on component clauses in record representation clauses that leave holes (haps) in the record layout. +@end table + +@geindex -gnatwi (gcc) + + +@table @asis + +@item @code{-gnatwi} -@item -gnatwi @emph{Activate warnings on implementation units.} -@cindex @option{-gnatwi} (@command{gcc}) -This switch activates warnings for a @code{with} of an internal GNAT -implementation unit, defined as any unit from the @code{Ada}, -@code{Interfaces}, @code{GNAT}, - or @code{System} + +This switch activates warnings for a @emph{with} of an internal GNAT +implementation unit, defined as any unit from the @cite{Ada}, +@cite{Interfaces}, @cite{GNAT}, +or @cite{System} hierarchies that is not documented in either the Ada Reference Manual or the GNAT Programmer's Reference Manual. Such units are intended only -for internal implementation purposes and should not be @code{with}'ed +for internal implementation purposes and should not be @emph{with}ed by user programs. The default is that such warnings are generated +@end table + +@geindex -gnatwI (gcc) + + +@table @asis + +@item @code{-gnatwI} -@item -gnatwI @emph{Disable warnings on implementation units.} -@cindex @option{-gnatwI} (@command{gcc}) -This switch disables warnings for a @code{with} of an internal GNAT + +This switch disables warnings for a @emph{with} of an internal GNAT implementation unit. +@end table + +@geindex -gnatw.i (gcc) + + +@table @asis + +@item @code{-gnatw.i} -@item -gnatw.i @emph{Activate warnings on overlapping actuals.} -@cindex @option{-gnatw.i} (@command{gcc}) + This switch enables a warning on statically detectable overlapping actuals in a subprogram call, when one of the actuals is an in-out parameter, and the types of the actuals are not by-copy types. This warning is off by default. +@end table + +@geindex -gnatw.I (gcc) + + +@table @asis + +@item @code{-gnatw.I} -@item -gnatw.I @emph{Disable warnings on overlapping actuals.} -@cindex @option{-gnatw.I} (@command{gcc}) + This switch disables warnings on overlapping actuals in a call.. +@end table + +@geindex -gnatwj (gcc) + + +@table @asis + +@item @code{-gnatwj} -@item -gnatwj @emph{Activate warnings on obsolescent features (Annex J).} -@cindex @option{-gnatwj} (@command{gcc}) -@cindex Features, obsolescent -@cindex Obsolescent features + +@geindex Features +@geindex obsolescent + +@geindex Obsolescent features + If this warning option is activated, then warnings are generated for -calls to subprograms marked with @code{pragma Obsolescent} and +calls to subprograms marked with @cite{pragma Obsolescent} and for use of features in Annex J of the Ada Reference Manual. In the case of Annex J, not all features are flagged. In particular use -of the renamed packages (like @code{Text_IO}) and use of package -@code{ASCII} are not flagged, since these are very common and +of the renamed packages (like @cite{Text_IO}) and use of package +@cite{ASCII} are not flagged, since these are very common and would generate many annoying positive warnings. The default is that such warnings are not generated. In addition to the above cases, warnings are also generated for GNAT features that have been provided in past versions but which have been superseded (typically by features in the new Ada standard). -For example, @code{pragma Ravenscar} will be flagged since its -function is replaced by @code{pragma Profile(Ravenscar)}, and -@code{pragma Interface_Name} will be flagged since its function -is replaced by @code{pragma Import}. +For example, @cite{pragma Ravenscar} will be flagged since its +function is replaced by @cite{pragma Profile(Ravenscar)}, and +@cite{pragma Interface_Name} will be flagged since its function +is replaced by @cite{pragma Import}. Note that this warning option functions differently from the -restriction @code{No_Obsolescent_Features} in two respects. +restriction @cite{No_Obsolescent_Features} in two respects. First, the restriction applies only to annex J features. -Second, the restriction does flag uses of package @code{ASCII}. +Second, the restriction does flag uses of package @cite{ASCII}. + +@item @code{-gnatwJ} -@item -gnatwJ @emph{Suppress warnings on obsolescent features (Annex J).} -@cindex @option{-gnatwJ} (@command{gcc}) +.. index:: -gnatwJ (gcc) + This switch disables warnings on use of obsolescent features. -@item -gnatwk +@item @code{-gnatwk} + @emph{Activate warnings on variables that could be constants.} -@cindex @option{-gnatwk} (@command{gcc}) +.. index:: -gnatwk (gcc) + This switch activates warnings for variables that are initialized but never modified, and then could be declared constants. The default is that such warnings are not given. +@end table + +@geindex -gnatwK (gcc) + + +@table @asis + +@item @code{-gnatwK} -@item -gnatwK @emph{Suppress warnings on variables that could be constants.} -@cindex @option{-gnatwK} (@command{gcc}) + This switch disables warnings on variables that could be declared constants. +@end table + +@geindex -gnatw.k (gcc) + + +@table @asis + +@item @code{-gnatw.k} -@item -gnatw.k @emph{Activate warnings on redefinition of names in standard.} -@cindex @option{-gnatw.k} (@command{gcc}) + This switch activates warnings for declarations that declare a name that is defined in package Standard. Such declarations can be confusing, especially since the names in package Standard continue to be directly visible, meaning that use visibiliy on such redeclared names does not work as expected. Names of discriminants and components in records are not included in this check. +@end table + +@geindex -gnatwK (gcc) + + +@table @asis + +@item @code{-gnatw.K} -@item -gnatw.K @emph{Suppress warnings on redefinition of names in standard.} -@cindex @option{-gnatwK} (@command{gcc}) + This switch activates warnings for declarations that declare a name that is defined in package Standard. +@end table + +@geindex -gnatwl (gcc) + + +@table @asis + +@item @code{-gnatwl} -@item -gnatwl @emph{Activate warnings for elaboration pragmas.} -@cindex @option{-gnatwl} (@command{gcc}) -@cindex Elaboration, warnings + +@geindex Elaboration +@geindex warnings + This switch activates warnings for possible elaboration problems, including suspicious use -of @code{Elaborate} pragmas, when using the static elaboration model, and -possible situations that may raise @code{Program_Error} when using the +of @cite{Elaborate} pragmas, when using the static elaboration model, and +possible situations that may raise @cite{Program_Error} when using the dynamic elaboration model. See the section in this guide on elaboration checking for further details. The default is that such warnings are not generated. +@end table + +@geindex -gnatwL (gcc) + + +@table @asis + +@item @code{-gnatwL} -@item -gnatwL @emph{Suppress warnings for elaboration pragmas.} -@cindex @option{-gnatwL} (@command{gcc}) + This switch suppresses warnings for possible elaboration problems. +@end table + +@geindex -gnatw.l (gcc) + + +@table @asis + +@item @code{-gnatw.l} -@item -gnatw.l @emph{List inherited aspects.} -@cindex @option{-gnatw.l} (@command{gcc}) + This switch causes the compiler to list inherited invariants, preconditions, and postconditions from Type_Invariant'Class, Invariant'Class, Pre'Class, and Post'Class aspects. Also list inherited subtype predicates. +@end table + +@geindex -gnatw.L (gcc) + + +@table @asis + +@item @code{-gnatw.L} -@item -gnatw.L @emph{Suppress listing of inherited aspects.} -@cindex @option{-gnatw.L} (@command{gcc}) + This switch suppresses listing of inherited aspects. +@end table + +@geindex -gnatwm (gcc) + + +@table @asis + +@item @code{-gnatwm} -@item -gnatwm @emph{Activate warnings on modified but unreferenced variables.} -@cindex @option{-gnatwm} (@command{gcc}) + This switch activates warnings for variables that are assigned (using an initialization value or with one or more assignment statements) but whose value is never read. The warning is suppressed for volatile variables and also for variables that are renamings of other variables or for which an address clause is given. The default is that these warnings are not given. +@end table + +@geindex -gnatwM (gcc) + + +@table @asis + +@item @code{-gnatwM} -@item -gnatwM @emph{Disable warnings on modified but unreferenced variables.} -@cindex @option{-gnatwM} (@command{gcc}) + This switch disables warnings for variables that are assigned or initialized, but never read. +@end table + +@geindex -gnatw.m (gcc) + + +@table @asis + +@item @code{-gnatw.m} -@item -gnatw.m @emph{Activate warnings on suspicious modulus values.} -@cindex @option{-gnatw.m} (@command{gcc}) + This switch activates warnings for modulus values that seem suspicious. The cases caught are where the size is the same as the modulus (e.g. a modulus of 7 with a size of 7 bits), and modulus values of 32 or 64 @@ -5265,55 +11442,111 @@ with no size clause. The guess in both cases is that 2**x was intended rather than x. In addition expressions of the form 2*x for small x generate a warning (the almost certainly accurate guess being that 2**x was intended). The default is that these warnings are given. +@end table + +@geindex -gnatw.M (gcc) + + +@table @asis + +@item @code{-gnatw.M} -@item -gnatw.M @emph{Disable warnings on suspicious modulus values.} -@cindex @option{-gnatw.M} (@command{gcc}) + This switch disables warnings for suspicious modulus values. +@end table + +@geindex -gnatwn (gcc) + + +@table @asis + +@item @code{-gnatwn} -@item -gnatwn @emph{Set normal warnings mode.} -@cindex @option{-gnatwn} (@command{gcc}) + This switch sets normal warning mode, in which enabled warnings are issued and treated as warnings rather than errors. This is the default -mode. the switch @option{-gnatwn} can be used to cancel the effect of -an explicit @option{-gnatws} or -@option{-gnatwe}. It also cancels the effect of the -implicit @option{-gnatwe} that is activated by the -use of @option{-gnatg}. +mode. the switch @emph{-gnatwn} can be used to cancel the effect of +an explicit @emph{-gnatws} or +@emph{-gnatwe}. It also cancels the effect of the +implicit @emph{-gnatwe} that is activated by the +use of @emph{-gnatg}. +@end table + +@geindex -gnatw.n (gcc) + +@geindex Atomic Synchronization +@geindex warnings + + +@table @asis + +@item @code{-gnatw.n} -@item -gnatw.n @emph{Activate warnings on atomic synchronization.} -@cindex @option{-gnatw.n} (@command{gcc}) -@cindex Atomic Synchronization, warnings + This switch actives warnings when an access to an atomic variable requires the generation of atomic synchronization code. These warnings are off by default. -@item -gnatw.N +@end table + +@geindex -gnatw.N (gcc) + + +@table @asis + +@item @code{-gnatw.N} + @emph{Suppress warnings on atomic synchronization.} -@cindex @option{-gnatw.n} (@command{gcc}) -@cindex Atomic Synchronization, warnings + +@geindex Atomic Synchronization +@geindex warnings + This switch suppresses warnings when an access to an atomic variable requires the generation of atomic synchronization code. +@end table + +@geindex -gnatwo (gcc) + +@geindex Address Clauses +@geindex warnings + + +@table @asis + +@item @code{-gnatwo} -@item -gnatwo @emph{Activate warnings on address clause overlays.} -@cindex @option{-gnatwo} (@command{gcc}) -@cindex Address Clauses, warnings + This switch activates warnings for possibly unintended initialization effects of defining address clauses that cause one variable to overlap another. The default is that such warnings are generated. +@end table + +@geindex -gnatwO (gcc) + + +@table @asis + +@item @code{-gnatwO} -@item -gnatwO @emph{Suppress warnings on address clause overlays.} -@cindex @option{-gnatwO} (@command{gcc}) + This switch suppresses warnings on possibly unintended initialization effects of defining address clauses that cause one variable to overlap another. +@end table + +@geindex -gnatw.o (gcc) + + +@table @asis + +@item @code{-gnatw.o} -@item -gnatw.o @emph{Activate warnings on modified but unreferenced out parameters.} -@cindex @option{-gnatw.o} (@command{gcc}) + This switch activates warnings for variables that are modified by using them as actuals for a call to a procedure with an out mode formal, where the resulting assigned value is never read. It is applicable in the case @@ -5323,37 +11556,69 @@ The warning is suppressed for volatile variables and also for variables that are renamings of other variables or for which an address clause is given. The default is that these warnings are not given. +@end table + +@geindex -gnatw.O (gcc) + + +@table @asis + +@item @code{-gnatw.O} -@item -gnatw.O @emph{Disable warnings on modified but unreferenced out parameters.} -@cindex @option{-gnatw.O} (@command{gcc}) + This switch suppresses warnings for variables that are modified by using them as actuals for a call to a procedure with an out mode formal, where the resulting assigned value is never read. +@end table + +@geindex -gnatwp (gcc) + +@geindex Inlining +@geindex warnings + + +@table @asis + +@item @code{-gnatwp} -@item -gnatwp @emph{Activate warnings on ineffective pragma Inlines.} -@cindex @option{-gnatwp} (@command{gcc}) -@cindex Inlining, warnings + This switch activates warnings for failure of front end inlining -(activated by @option{-gnatN}) to inline a particular call. There are +(activated by @emph{-gnatN}) to inline a particular call. There are many reasons for not being able to inline a call, including most commonly that the call is too complex to inline. The default is that such warnings are not given. Warnings on ineffective inlining by the gcc back-end can be activated separately, using the gcc switch -Winline. +@end table + +@geindex -gnatwP (gcc) + + +@table @asis + +@item @code{-gnatwP} -@item -gnatwP @emph{Suppress warnings on ineffective pragma Inlines.} -@cindex @option{-gnatwP} (@command{gcc}) + This switch suppresses warnings on ineffective pragma Inlines. If the inlining mechanism cannot inline a call, it will simply ignore the request silently. +@end table + +@geindex -gnatw.p (gcc) + +@geindex Parameter order +@geindex warnings + + +@table @asis + +@item @code{-gnatw.p} -@item -gnatw.p @emph{Activate warnings on parameter ordering.} -@cindex @option{-gnatw.p} (@command{gcc}) -@cindex Parameter order, warnings + This switch activates warnings for cases of suspicious parameter ordering when the list of arguments are all simple identifiers that match the names of the formals, but are in a different order. The @@ -5361,17 +11626,33 @@ warning is suppressed if any use of named parameter notation is used, so this is the appropriate way to suppress a false positive (and serves to emphasize that the "misordering" is deliberate). The default is that such warnings are not given. +@end table + +@geindex -gnatw.P (gcc) + + +@table @asis + +@item @code{-gnatw.P} -@item -gnatw.P @emph{Suppress warnings on parameter ordering.} -@cindex @option{-gnatw.P} (@command{gcc}) + This switch suppresses warnings on cases of suspicious parameter ordering. +@end table + +@geindex -gnatwq (gcc) + +@geindex Parentheses +@geindex warnings + + +@table @asis + +@item @code{-gnatwq} -@item -gnatwq @emph{Activate warnings on questionable missing parentheses.} -@cindex @option{-gnatwq} (@command{gcc}) -@cindex Parentheses, warnings + This switch activates warnings for cases where parentheses are not used and the result is potential ambiguity from a readers point of view. For example (not a > b) when a and b are modular means ((not a) > b) and very likely the @@ -5380,185 +11661,327 @@ quite likely ((-x) mod 5) was intended. In such situations it seems best to follow the rule of always parenthesizing to make the association clear, and this warning switch warns if such parentheses are not present. The default is that these warnings are given. +@end table + +@geindex -gnatwQ (gcc) + + +@table @asis + +@item @code{-gnatwQ} -@item -gnatwQ @emph{Suppress warnings on questionable missing parentheses.} -@cindex @option{-gnatwQ} (@command{gcc}) + This switch suppresses warnings for cases where the association is not clear and the use of parentheses is preferred. +@end table + +@geindex -gnatwr (gcc) + + +@table @asis + +@item @code{-gnatwr} -@item -gnatwr @emph{Activate warnings on redundant constructs.} -@cindex @option{-gnatwr} (@command{gcc}) + This switch activates warnings for redundant constructs. The following is the current list of constructs regarded as redundant: -@itemize @bullet -@item + +@itemize * + +@item Assignment of an item to itself. -@item + +@item Type conversion that converts an expression to its own type. -@item -Use of the attribute @code{Base} where @code{typ'Base} is the same -as @code{typ}. -@item -Use of pragma @code{Pack} when all components are placed by a record + +@item +Use of the attribute @cite{Base} where @cite{typ'Base} is the same +as @cite{typ}. + +@item +Use of pragma @cite{Pack} when all components are placed by a record representation clause. -@item + +@item Exception handler containing only a reraise statement (raise with no operand) which has no effect. -@item + +@item Use of the operator abs on an operand that is known at compile time to be non-negative -@item + +@item Comparison of boolean expressions to an explicit True value. @end itemize The default is that warnings for redundant constructs are not given. +@end table + +@geindex -gnatwR (gcc) + + +@table @asis + +@item @code{-gnatwR} -@item -gnatwR @emph{Suppress warnings on redundant constructs.} -@cindex @option{-gnatwR} (@command{gcc}) + This switch suppresses warnings for redundant constructs. +@end table + +@geindex -gnatw.r (gcc) + + +@table @asis + +@item @code{-gnatw.r} -@item -gnatw.r @emph{Activate warnings for object renaming function.} -@cindex @option{-gnatw.r} (@command{gcc}) + This switch activates warnings for an object renaming that renames a function call, which is equivalent to a constant declaration (as opposed to renaming the function itself). The default is that these warnings are given. +@end table + +@geindex -gnatwT (gcc) + + +@table @asis + +@item @code{-gnatw.R} -@item -gnatw.R @emph{Suppress warnings for object renaming function.} -@cindex @option{-gnatwT} (@command{gcc}) + This switch suppresses warnings for object renaming function. +@end table + +@geindex -gnatws (gcc) + + +@table @asis + +@item @code{-gnatws} -@item -gnatws @emph{Suppress all warnings.} -@cindex @option{-gnatws} (@command{gcc}) + This switch completely suppresses the output of all warning messages from the GNAT front end, including both warnings that can be controlled by switches described in this section, and those that are normally given unconditionally. The effect of this suppress action can only be cancelled by a subsequent -use of the switch @option{-gnatwn}. +use of the switch @emph{-gnatwn}. -Note that switch @option{-gnatws} does not suppress -warnings from the @command{gcc} back end. -To suppress these back end warnings as well, use the switch @option{-w} -in addition to @option{-gnatws}. Also this switch has no effect on the +Note that switch @emph{-gnatws} does not suppress +warnings from the @emph{gcc} back end. +To suppress these back end warnings as well, use the switch @emph{-w} +in addition to @emph{-gnatws}. Also this switch has no effect on the handling of style check messages. +@end table + +@geindex -gnatw.s (gcc) + +@geindex Record Representation (component sizes) + + +@table @asis + +@item @code{-gnatw.s} -@item -gnatw.s @emph{Activate warnings on overridden size clauses.} -@cindex @option{-gnatw.s} (@command{gcc}) -@cindex Record Representation (component sizes) + This switch activates warnings on component clauses in record representation clauses where the length given overrides that specified by an explicit size clause for the component type. A warning is similarly given in the array case if a specified component size overrides an explicit size clause for the array component type. +@end table + +@geindex -gnatw.S (gcc) + + +@table @asis + +@item @code{-gnatw.S} -@item -gnatw.S @emph{Suppress warnings on overridden size clauses.} -@cindex @option{-gnatw.S} (@command{gcc}) + This switch suppresses warnings on component clauses in record representation clauses that override size clauses, and similar warnings when an array component size overrides a size clause. +@end table + +@geindex -gnatwt (gcc) + +@geindex Deactivated code +@geindex warnings + +@geindex Deleted code +@geindex warnings + + +@table @asis + +@item @code{-gnatwt} -@item -gnatwt @emph{Activate warnings for tracking of deleted conditional code.} -@cindex @option{-gnatwt} (@command{gcc}) -@cindex Deactivated code, warnings -@cindex Deleted code, warnings + This switch activates warnings for tracking of code in conditionals (IF and CASE statements) that is detected to be dead code which cannot be executed, and which is removed by the front end. This warning is off by default. This may be useful for detecting deactivated code in certified applications. +@end table + +@geindex -gnatwT (gcc) + + +@table @asis + +@item @code{-gnatwT} -@item -gnatwT @emph{Suppress warnings for tracking of deleted conditional code.} -@cindex @option{-gnatwT} (@command{gcc}) + This switch suppresses warnings for tracking of deleted conditional code. +@end table + +@geindex -gnatw.t (gcc) + + +@table @asis + +@item @code{-gnatw.t} -@item -gnatw.t @emph{Activate warnings on suspicious contracts.} -@cindex @option{-gnatw.t} (@command{gcc}) -This switch activates warnings on suspicious postconditions (whether a -pragma @code{Postcondition} or a @code{Post} aspect in Ada 2012) -and suspicious contract cases (pragma @code{Contract_Cases}). A -function postcondition or contract case is suspicious when no postcondition -or contract case for this function mentions the result of the function. -A procedure postcondition or contract case is suspicious when it only -refers to the pre-state of the procedure, because in that case it should -rather be expressed as a precondition. The default is that such warnings -are not generated. -@item -gnatw.T +This switch activates warnings on suspicious contracts. This includes +warnings on suspicious postconditions (whether a pragma @cite{Postcondition} or a +@cite{Post} aspect in Ada 2012) and suspicious contract cases (pragma or aspect +@cite{Contract_Cases}). A function postcondition or contract case is suspicious +when no postcondition or contract case for this function mentions the result +of the function. A procedure postcondition or contract case is suspicious +when it only refers to the pre-state of the procedure, because in that case +it should rather be expressed as a precondition. This switch also controls +warnings on suspicious cases of expressions typically found in contracts like +quantified expressions and uses of Update attribute. The default is that such +warnings are generated. +@end table + +@geindex -gnatw.T (gcc) + + +@table @asis + +@item @code{-gnatw.T} + @emph{Suppress warnings on suspicious contracts.} -@cindex @option{-gnatw.T} (@command{gcc}) -This switch suppresses warnings on suspicious postconditions. -@item -gnatwu +This switch suppresses warnings on suspicious contracts. +@end table + +@geindex -gnatwu (gcc) + + +@table @asis + +@item @code{-gnatwu} + @emph{Activate warnings on unused entities.} -@cindex @option{-gnatwu} (@command{gcc}) + This switch activates warnings to be generated for entities that -are declared but not referenced, and for units that are @code{with}'ed +are declared but not referenced, and for units that are @emph{with}ed and not referenced. In the case of packages, a warning is also generated if no entities in the package are referenced. This means that if a with'ed -package is referenced but the only references are in @code{use} -clauses or @code{renames} +package is referenced but the only references are in @cite{use} +clauses or @cite{renames} declarations, a warning is still generated. A warning is also generated -for a generic package that is @code{with}'ed but never instantiated. +for a generic package that is @emph{with}ed but never instantiated. In the case where a package or subprogram body is compiled, and there -is a @code{with} on the corresponding spec +is a @emph{with} on the corresponding spec that is only referenced in the body, a warning is also generated, noting that the -@code{with} can be moved to the body. The default is that +@emph{with} can be moved to the body. The default is that such warnings are not generated. This switch also activates warnings on unreferenced formals -(it includes the effect of @option{-gnatwf}). +(it includes the effect of @emph{-gnatwf}). +@end table + +@geindex -gnatwU (gcc) + + +@table @asis + +@item @code{-gnatwU} -@item -gnatwU @emph{Suppress warnings on unused entities.} -@cindex @option{-gnatwU} (@command{gcc}) + This switch suppresses warnings for unused entities and packages. It also turns off warnings on unreferenced formals (and thus includes -the effect of @option{-gnatwF}). +the effect of @emph{-gnatwF}). +@end table + +@geindex -gnatw.u (gcc) + + +@table @asis + +@item @code{-gnatw.u} -@item -gnatw.u @emph{Activate warnings on unordered enumeration types.} -@cindex @option{-gnatw.u} (@command{gcc}) + This switch causes enumeration types to be considered as conceptually -unordered, unless an explicit pragma @code{Ordered} is given for the type. +unordered, unless an explicit pragma @cite{Ordered} is given for the type. The effect is to generate warnings in clients that use explicit comparisons or subranges, since these constructs both treat objects of the type as ordered. (A @emph{client} is defined as a unit that is other than the unit in which the type is declared, or its body or subunits.) Please refer to -the description of pragma @code{Ordered} in the -@cite{@value{EDITION} Reference Manual} for further details. +the description of pragma @cite{Ordered} in the +@cite{GNAT Reference Manual} for further details. The default is that such warnings are not generated. +@end table + +@geindex -gnatw.U (gcc) + + +@table @asis + +@item @code{-gnatw.U} -@item -gnatw.U @emph{Deactivate warnings on unordered enumeration types.} -@cindex @option{-gnatw.U} (@command{gcc}) + This switch causes all enumeration types to be considered as ordered, so that no warnings are given for comparisons or subranges for any type. +@end table + +@geindex -gnatwv (gcc) + +@geindex Unassigned variable warnings + + +@table @asis + +@item @code{-gnatwv} -@item -gnatwv @emph{Activate warnings on unassigned variables.} -@cindex @option{-gnatwv} (@command{gcc}) -@cindex Unassigned variable warnings + This switch activates warnings for access to variables which may not be properly initialized. The default is that such warnings are generated. +@end table + +@geindex -gnatwV (gcc) + + +@table @asis + +@item @code{-gnatwV} -@item -gnatwV @emph{Suppress warnings on unassigned variables.} -@cindex @option{-gnatwV} (@command{gcc}) + This switch suppresses warnings for access to variables which may not be properly initialized. For variables of a composite type, the warning can also be suppressed in @@ -5566,76 +11989,128 @@ Ada 2005 by using a default initialization with a box. For example, if Table is an array of records whose components are only partially uninitialized, then the following code: -@smallexample @c ada - Tab : Table := (@b{others} => <>); -@end smallexample +@example +Tab : Table := (others => <>); +@end example will suppress warnings on subsequent statements that access components of variable Tab. +@end table + +@geindex -gnatw.v (gcc) + +@geindex bit order warnings + + +@table @asis + +@item @code{-gnatw.v} -@item -gnatw.v @emph{Activate info messages for non-default bit order.} -@cindex @option{-gnatw.v} (@command{gcc}) -@cindex bit order warnings + This switch activates messages (labeled "info", they are not warnings, just informational messages) about the effects of non-default bit-order on records to which a component clause is applied. The effect of specifying non-default bit ordering is a bit subtle (and changed with Ada 2005), so these messages, which are given by default, are useful in understanding the exact consequences of using this feature. +@end table + +@geindex -gnatw.V (gcc) + + +@table @asis + +@item @code{-gnatw.V} -@item -gnatw.V @emph{Suppress info messages for non-default bit order.} -@cindex @option{-gnatw.V} (@command{gcc}) + This switch suppresses information messages for the effects of specifying non-default bit order on record components with component clauses. +@end table + +@geindex -gnatww (gcc) + +@geindex String indexing warnings + + +@table @asis + +@item @code{-gnatww} -@item -gnatww @emph{Activate warnings on wrong low bound assumption.} -@cindex @option{-gnatww} (@command{gcc}) -@cindex String indexing warnings + This switch activates warnings for indexing an unconstrained string parameter with a literal or S'Length. This is a case where the code is assuming that the low bound is one, which is in general not true (for example when a slice is passed). The default is that such warnings are generated. +@end table + +@geindex -gnatwW (gcc) + + +@table @asis + +@item @code{-gnatwW} -@item -gnatwW @emph{Suppress warnings on wrong low bound assumption.} -@cindex @option{-gnatwW} (@command{gcc}) + This switch suppresses warnings for indexing an unconstrained string parameter with a literal or S'Length. Note that this warning can also be suppressed -in a particular case by adding an -assertion that the lower bound is 1, -as shown in the following example. +in a particular case by adding an assertion that the lower bound is 1, +as shown in the following example: + +@example +procedure K (S : String) is + pragma Assert (S'First = 1); + ... +@end example +@end table + +@geindex -gnatw.w (gcc) + +@geindex Warnings Off control + -@smallexample @c ada - @b{procedure} K (S : String) @b{is} - @b{pragma} Assert (S'First = 1); - @dots{} -@end smallexample +@table @asis + +@item @code{-gnatw.w} -@item -gnatw.w @emph{Activate warnings on Warnings Off pragmas} -@cindex @option{-gnatw.w} (@command{gcc}) -@cindex Warnings Off control -This switch activates warnings for use of @code{pragma Warnings (Off, entity)} + +This switch activates warnings for use of @cite{pragma Warnings (Off@comma{} entity)} where either the pragma is entirely useless (because it suppresses no -warnings), or it could be replaced by @code{pragma Unreferenced} or -@code{pragma Unmodified}. +warnings), or it could be replaced by @cite{pragma Unreferenced} or +@cite{pragma Unmodified}. Also activates warnings for the case of Warnings (Off, String), where either there is no matching Warnings (On, String), or the Warnings (Off) did not suppress any warning. The default is that these warnings are not given. +@end table + +@geindex -gnatw.W (gcc) + + +@table @asis + +@item @code{-gnatw.W} -@item -gnatw.W @emph{Suppress warnings on unnecessary Warnings Off pragmas} -@cindex @option{-gnatw.W} (@command{gcc}) -This switch suppresses warnings for use of @code{pragma Warnings (Off, ...)}. -@item -gnatwx +This switch suppresses warnings for use of @cite{pragma Warnings (Off@comma{} ...)}. +@end table + +@geindex -gnatwx (gcc) + +@geindex Export/Import pragma warnings + + +@table @asis + +@item @code{-gnatwx} + @emph{Activate warnings on Export/Import pragmas.} -@cindex @option{-gnatwx} (@command{gcc}) -@cindex Export/Import pragma warnings + This switch activates warnings on Export/Import pragmas when the compiler detects a possible conflict between the Ada and foreign language calling sequences. For example, the use of @@ -5643,54 +12118,94 @@ default parameters in a convention C procedure is dubious because the C compiler cannot supply the proper default, so a warning is issued. The default is that such warnings are generated. +@end table + +@geindex -gnatwX (gcc) + + +@table @asis + +@item @code{-gnatwX} -@item -gnatwX @emph{Suppress warnings on Export/Import pragmas.} -@cindex @option{-gnatwX} (@command{gcc}) + This switch suppresses warnings on Export/Import pragmas. The sense of this is that you are telling the compiler that you know what you are doing in writing the pragma, and it should not complain at you. +@end table + +@geindex -gnatwm (gcc) + + +@table @asis + +@item @code{-gnatw.x} -@item -gnatw.x @emph{Activate warnings for No_Exception_Propagation mode.} -@cindex @option{-gnatwm} (@command{gcc}) + This switch activates warnings for exception usage when pragma Restrictions (No_Exception_Propagation) is in effect. Warnings are given for implicit or explicit exception raises which are not covered by a local handler, and for exception handlers which do not cover a local raise. The default is that these warnings are not given. -@item -gnatw.X +@item @code{-gnatw.X} + @emph{Disable warnings for No_Exception_Propagation mode.} + This switch disables warnings for exception usage when pragma Restrictions (No_Exception_Propagation) is in effect. +@end table + +@geindex -gnatwy (gcc) + +@geindex Ada compatibility issues warnings + + +@table @asis + +@item @code{-gnatwy} -@item -gnatwy @emph{Activate warnings for Ada compatibility issues.} -@cindex @option{-gnatwy} (@command{gcc}) -@cindex Ada compatibility issues warnings + For the most part, newer versions of Ada are upwards compatible with older versions. For example, Ada 2005 programs will almost always work when compiled as Ada 2012. However there are some exceptions (for example the fact that -@code{some} is now a reserved word in Ada 2012). This +@cite{some} is now a reserved word in Ada 2012). This switch activates several warnings to help in identifying and correcting such incompatibilities. The default is that these warnings are generated. Note that at one point Ada 2005 was called Ada 0Y, hence the choice of character. +@end table + +@geindex -gnatwY (gcc) + +@geindex Ada compatibility issues warnings + + +@table @asis + +@item @code{-gnatwY} -@item -gnatwY @emph{Disable warnings for Ada compatibility issues.} -@cindex @option{-gnatwY} (@command{gcc}) -@cindex Ada compatibility issues warnings + This switch suppresses the warnings intended to help in identifying incompatibilities between Ada language versions. +@end table + +@geindex -gnatw.y (gcc) + +@geindex Package spec needing body + + +@table @asis + +@item @code{-gnatw.y} -@item -gnatw.y @emph{Activate information messages for why package spec needs body} -@cindex @option{-gnatw.y} (@command{gcc}) -@cindex Package spec needing body + There are a number of cases in which a package spec needs a body. For example, the use of pragma Elaborate_Body, or the declaration of a procedure specification requiring a completion. This switch @@ -5698,195 +12213,343 @@ causes information messages to be output showing why a package specification requires a body. This can be useful in the case of a large package specification which is unexpectedly requiring a body. The default is that such information messages are not output. +@end table + +@geindex -gnatw.Y (gcc) + +@geindex No information messages for why package spec needs body + + +@table @asis + +@item @code{-gnatw.Y} -@item -gnatw.Y @emph{Disable information messages for why package spec needs body} -@cindex @option{-gnatw.Y} (@command{gcc}) -@cindex No information messages for why package spec needs body + This switch suppresses the output of information messages showing why a package specification needs a body. +@end table + +@geindex -gnatwz (gcc) + +@geindex Unchecked_Conversion warnings + + +@table @asis + +@item @code{-gnatwz} -@item -gnatwz @emph{Activate warnings on unchecked conversions.} -@cindex @option{-gnatwz} (@command{gcc}) -@cindex Unchecked_Conversion warnings + This switch activates warnings for unchecked conversions where the types are known at compile time to have different -sizes. The default -is that such warnings are generated. Warnings are also -generated for subprogram pointers with different conventions, -and, on VMS only, for data pointers with different conventions. +sizes. The default is that such warnings are generated. Warnings are also +generated for subprogram pointers with different conventions. +@end table + +@geindex -gnatwZ (gcc) + + +@table @asis + +@item @code{-gnatwZ} -@item -gnatwZ @emph{Suppress warnings on unchecked conversions.} -@cindex @option{-gnatwZ} (@command{gcc}) + This switch suppresses warnings for unchecked conversions where the types are known at compile time to have different sizes or conventions. +@end table + +@geindex -gnatw.z (gcc) + +@geindex Size/Alignment warnings + + +@table @asis + +@item @code{-gnatw.z} -@item -gnatw.z @emph{Activate warnings for size not a multiple of alignment.} -@cindex @option{-gnatw.z} (@command{gcc}) -@cindex Size/Alignment warnings + This switch activates warnings for cases of record types with -specified @code{Size} and @code{Alignment} attributes where the +specified @cite{Size} and @cite{Alignment} attributes where the size is not a multiple of the alignment, resulting in an object size that is greater than the specified size. The default is that such warnings are generated. +@end table + +@geindex -gnatw.Z (gcc) + +@geindex Size/Alignment warnings + + +@table @asis + +@item @code{-gnatw.Z} -@item -gnatw.Z @emph{Suppress warnings for size not a multiple of alignment.} -@cindex @option{-gnatw.Z} (@command{gcc}) -@cindex Size/Alignment warnings + This switch suppresses warnings for cases of record types with -specified @code{Size} and @code{Alignment} attributes where the +specified @cite{Size} and @cite{Alignment} attributes where the size is not a multiple of the alignment, resulting in an object size that is greater than the specified size. The warning can also be -suppressed by giving an explicit @code{Object_Size} value. - -@item -Wunused -@cindex @option{-Wunused} -The warnings controlled by the @option{-gnatw} switch are generated by -the front end of the compiler. The @option{GCC} back end can provide -additional warnings and they are controlled by the @option{-W} switch. -For example, @option{-Wunused} activates back end +suppressed by giving an explicit @cite{Object_Size} value. +@end table + +@geindex -Wunused (gcc) + + +@table @asis + +@item @code{-Wunused} + +The warnings controlled by the @emph{-gnatw} switch are generated by +the front end of the compiler. The @emph{GCC} back end can provide +additional warnings and they are controlled by the @emph{-W} switch. +For example, @emph{-Wunused} activates back end warnings for entities that are declared but not referenced. +@end table + +@geindex -Wuninitialized (gcc) + + +@table @asis + +@item @code{-Wuninitialized} -@item -Wuninitialized -@cindex @option{-Wuninitialized} -Similarly, @option{-Wuninitialized} activates +Similarly, @emph{-Wuninitialized} activates the back end warning for uninitialized variables. This switch must be used in conjunction with an optimization level greater than zero. +@end table + +@geindex -Wstack-usage (gcc) + -@item -Wstack-usage=@var{len} -@cindex @option{-Wstack-usage} -Warn if the stack usage of a subprogram might be larger than @var{len} bytes. -See @ref{Static Stack Usage Analysis} for details. +@table @asis + +@item @code{-Wstack-usage=@emph{len}} + +Warn if the stack usage of a subprogram might be larger than @cite{len} bytes. +See @ref{fa,,Static Stack Usage Analysis} for details. +@end table -@item -Wall -@cindex @option{-Wall} -This switch enables most warnings from the @option{GCC} back end. +@geindex -Wall (gcc) + + +@table @asis + +@item @code{-Wall} + +This switch enables most warnings from the @emph{GCC} back end. The code generator detects a number of warning situations that are missed -by the @option{GNAT} front end, and this switch can be used to activate them. +by the @emph{GNAT} front end, and this switch can be used to activate them. The use of this switch also sets the default front end warning mode to -@option{-gnatwa}, that is, most front end warnings activated as well. +@emph{-gnatwa}, that is, most front end warnings activated as well. +@end table + +@geindex -w (gcc) + -@item -w -@cindex @option{-w} -Conversely, this switch suppresses warnings from the @option{GCC} back end. +@table @asis + +@item @code{-w} + +Conversely, this switch suppresses warnings from the @emph{GCC} back end. The use of this switch also sets the default front end warning mode to -@option{-gnatws}, that is, front end warnings suppressed as well. +@emph{-gnatws}, that is, front end warnings suppressed as well. +@end table + +@geindex -Werror (gcc) + + +@table @asis -@item -Werror -@cindex @option{-Werror} -This switch causes warnings from the @option{GCC} back end to be treated as +@item @code{-Werror} + +This switch causes warnings from the @emph{GCC} back end to be treated as errors. The warning string still appears, but the warning messages are counted as errors, and prevent the generation of an object file. - @end table -@noindent A string of warning parameters can be used in the same parameter. For example: -@smallexample +@example -gnatwaGe -@end smallexample +@end example -@noindent will turn on all optional warnings except for unrecognized pragma warnings, and also specify that warnings should be treated as errors. -When no switch @option{-gnatw} is used, this is equivalent to: - -@table @option -@c !sort! -@item -gnatw.a -@item -gnatwB -@item -gnatw.b -@item -gnatwC -@item -gnatw.C -@item -gnatwD -@item -gnatwF -@item -gnatwg -@item -gnatwH -@item -gnatwi -@item -gnatw.I -@item -gnatwJ -@item -gnatwK -@item -gnatwL -@item -gnatw.L -@item -gnatwM -@item -gnatw.m -@item -gnatwn -@item -gnatwo -@item -gnatw.O -@item -gnatwP -@item -gnatw.P -@item -gnatwq -@item -gnatwR -@item -gnatw.R -@item -gnatw.S -@item -gnatwT -@item -gnatw.T -@item -gnatwU -@item -gnatwv -@item -gnatww -@item -gnatw.W -@item -gnatwx -@item -gnatw.X -@item -gnatwy -@item -gnatwz - -@end table - -@node Debugging and Assertion Control +When no switch @emph{-gnatw} is used, this is equivalent to: + +@quotation + + +@itemize * + +@item +@code{-gnatw.a} + +@item +@code{-gnatwB} + +@item +@code{-gnatw.b} + +@item +@code{-gnatwC} + +@item +@code{-gnatw.C} + +@item +@code{-gnatwD} + +@item +@code{-gnatwF} + +@item +@code{-gnatwg} + +@item +@code{-gnatwH} + +@item +@code{-gnatwi} + +@item +@code{-gnatw.I} + +@item +@code{-gnatwJ} + +@item +@code{-gnatwK} + +@item +@code{-gnatwL} + +@item +@code{-gnatw.L} + +@item +@code{-gnatwM} + +@item +@code{-gnatw.m} + +@item +@code{-gnatwn} + +@item +@code{-gnatwo} + +@item +@code{-gnatw.O} + +@item +@code{-gnatwP} + +@item +@code{-gnatw.P} + +@item +@code{-gnatwq} + +@item +@code{-gnatwR} + +@item +@code{-gnatw.R} + +@item +@code{-gnatw.S} + +@item +@code{-gnatwT} + +@item +@code{-gnatw.T} + +@item +@code{-gnatwU} + +@item +@code{-gnatwv} + +@item +@code{-gnatww} + +@item +@code{-gnatw.W} + +@item +@code{-gnatwx} + +@item +@code{-gnatw.X} + +@item +@code{-gnatwy} + +@item +@code{-gnatwz} +@end itemize +@end quotation + +@node Debugging and Assertion Control,Validity Checking,Warning Message Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat debugging-and-assertion-control}@anchor{105}@anchor{gnat_ugn/building_executable_programs_with_gnat id16}@anchor{106} @subsection Debugging and Assertion Control -@table @option -@item -gnata -@cindex @option{-gnata} (@command{gcc}) -@findex Assert -@findex Debug -@cindex Assertions -@noindent -The pragmas @code{Assert} and @code{Debug} normally have no effect and -are ignored. This switch, where @samp{a} stands for assert, causes -@code{Assert} and @code{Debug} pragmas to be activated. +@geindex -gnata (gcc) + + +@table @asis + +@item @code{-gnata} + +@geindex Assert + +@geindex Debug + +@geindex Assertions + +The pragmas @cite{Assert} and @cite{Debug} normally have no effect and +are ignored. This switch, where @code{a} stands for assert, causes +@cite{Assert} and @cite{Debug} pragmas to be activated. The pragmas have the form: -@smallexample -@cartouche - @b{pragma} Assert (@var{Boolean-expression} @r{[}, - @var{static-string-expression}@r{]}) - @b{pragma} Debug (@var{procedure call}) -@end cartouche -@end smallexample +@example +pragma Assert (<Boolean-expression> [, <static-string-expression>]) +pragma Debug (<procedure call>) +@end example -@noindent -The @code{Assert} pragma causes @var{Boolean-expression} to be tested. -If the result is @code{True}, the pragma has no effect (other than +The @cite{Assert} pragma causes @cite{Boolean-expression} to be tested. +If the result is @cite{True}, the pragma has no effect (other than possible side effects from evaluating the expression). If the result is -@code{False}, the exception @code{Assert_Failure} declared in the package -@code{System.Assertions} is -raised (passing @var{static-string-expression}, if present, as the +@cite{False}, the exception @cite{Assert_Failure} declared in the package +@cite{System.Assertions} is +raised (passing @cite{static-string-expression}, if present, as the message associated with the exception). If no string expression is given the default is a string giving the file name and line number of the pragma. -The @code{Debug} pragma causes @var{procedure} to be called. Note that -@code{pragma Debug} may appear within a declaration sequence, allowing +The @cite{Debug} pragma causes @cite{procedure} to be called. Note that +@cite{pragma Debug} may appear within a declaration sequence, allowing debugging procedures to be called between declarations. - @end table -@node Validity Checking +@node Validity Checking,Style Checking,Debugging and Assertion Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat validity-checking}@anchor{fb}@anchor{gnat_ugn/building_executable_programs_with_gnat id17}@anchor{107} @subsection Validity Checking -@findex Validity Checking -@noindent + +@geindex Validity Checking + The Ada Reference Manual defines the concept of invalid values (see RM 13.9.1). The primary source of invalid values is uninitialized variables. A scalar variable that is left uninitialized may contain @@ -5896,14 +12559,14 @@ composite types. It is an error to read an invalid value, but the RM does not require run-time checks to detect such errors, except for some minimal checking to prevent erroneous execution (i.e. unpredictable -behavior). This corresponds to the @option{-gnatVd} switch below, +behavior). This corresponds to the @emph{-gnatVd} switch below, which is the default. For example, by default, if the expression of a case statement is invalid, it will raise Constraint_Error rather than causing a wild jump, and if an array index on the left-hand side of an assignment is invalid, it will raise Constraint_Error rather than overwriting an arbitrary memory location. -The @option{-gnatVa} may be used to enable additional validity checks, +The @emph{-gnatVa} may be used to enable additional validity checks, which are not required by the RM. These checks are often very expensive (which is why the RM does not require them). These checks are useful in tracking down uninitialized variables, but they are @@ -5913,197 +12576,273 @@ combination with optimization, since this can confuse the optimizer. If performance is a consideration, leading to the need to optimize, then the validity checking options should not be used. -The other @option{-gnatV@var{x}} switches below allow finer-grained +The other @emph{-gnatV}@code{x} switches below allow finer-grained control; you can enable whichever validity checks you desire. However, -for most debugging purposes, @option{-gnatVa} is sufficient, and the -default @option{-gnatVd} (i.e. standard Ada behavior) is usually +for most debugging purposes, @emph{-gnatVa} is sufficient, and the +default @emph{-gnatVd} (i.e. standard Ada behavior) is usually sufficient for non-debugging use. -The @option{-gnatB} switch tells the compiler to assume that all +The @emph{-gnatB} switch tells the compiler to assume that all values are valid (that is, within their declared subtype range) except in the context of a use of the Valid attribute. This means the compiler can generate more efficient code, since the range of values is better known at compile time. However, an uninitialized variable can cause wild jumps and memory corruption in this mode. -The @option{-gnatV@var{x}} switch allows control over the validity +The @emph{-gnatV}@code{x} switch allows control over the validity checking mode as described below. The @code{x} argument is a string of letters that indicate validity checks that are performed or not performed in addition to the default checks required by Ada as described above. -@table @option -@c !sort! -@item -gnatVa +@geindex -gnatVa (gcc) + + +@table @asis + +@item @code{-gnatVa} + @emph{All validity checks.} -@cindex @option{-gnatVa} (@command{gcc}) + All validity checks are turned on. -That is, @option{-gnatVa} is -equivalent to @option{gnatVcdfimorst}. +That is, @emph{-gnatVa} is +equivalent to @emph{gnatVcdfimorst}. +@end table + +@geindex -gnatVc (gcc) + + +@table @asis + +@item @code{-gnatVc} -@item -gnatVc @emph{Validity checks for copies.} -@cindex @option{-gnatVc} (@command{gcc}) + The right hand side of assignments, and the initializing values of object declarations are validity checked. +@end table + +@geindex -gnatVd (gcc) + + +@table @asis + +@item @code{-gnatVd} -@item -gnatVd @emph{Default (RM) validity checks.} -@cindex @option{-gnatVd} (@command{gcc}) + Some validity checks are done by default following normal Ada semantics (RM 13.9.1 (9-11)). A check is done in case statements that the expression is within the range of the subtype. If it is not, Constraint_Error is raised. For assignments to array components, a check is done that the expression used as index is within the range. If it is not, Constraint_Error is raised. -Both these validity checks may be turned off using switch @option{-gnatVD}. -They are turned on by default. If @option{-gnatVD} is specified, a subsequent -switch @option{-gnatVd} will leave the checks turned on. -Switch @option{-gnatVD} should be used only if you are sure that all such +Both these validity checks may be turned off using switch @emph{-gnatVD}. +They are turned on by default. If @emph{-gnatVD} is specified, a subsequent +switch @emph{-gnatVd} will leave the checks turned on. +Switch @emph{-gnatVD} should be used only if you are sure that all such expressions have valid values. If you use this switch and invalid values are present, then the program is erroneous, and wild jumps or memory overwriting may occur. +@end table + +@geindex -gnatVe (gcc) + + +@table @asis + +@item @code{-gnatVe} -@item -gnatVe @emph{Validity checks for elementary components.} -@cindex @option{-gnatVe} (@command{gcc}) + In the absence of this switch, assignments to record or array components are not validity checked, even if validity checks for assignments generally -(@option{-gnatVc}) are turned on. In Ada, assignment of composite values do not +(@emph{-gnatVc}) are turned on. In Ada, assignment of composite values do not require valid data, but assignment of individual components does. So for example, there is a difference between copying the elements of an array with a slice assignment, compared to assigning element by element in a loop. This switch allows you to turn off validity checking for components, even when they are assigned component by component. +@end table + +@geindex -gnatVf (gcc) + + +@table @asis + +@item @code{-gnatVf} -@item -gnatVf @emph{Validity checks for floating-point values.} -@cindex @option{-gnatVf} (@command{gcc}) + In the absence of this switch, validity checking occurs only for discrete -values. If @option{-gnatVf} is specified, then validity checking also applies +values. If @emph{-gnatVf} is specified, then validity checking also applies for floating-point values, and NaNs and infinities are considered invalid, as well as out of range values for constrained types. Note that this means that standard IEEE infinity mode is not allowed. The exact contexts in which floating-point values are checked depends on the setting of other -options. For example, -@option{-gnatVif} or -@option{-gnatVfi} +options. For example, @emph{-gnatVif} or @emph{-gnatVfi} (the order does not matter) specifies that floating-point parameters of mode -@code{in} should be validity checked. +@cite{in} should be validity checked. +@end table + +@geindex -gnatVi (gcc) + + +@table @asis + +@item @code{-gnatVi} -@item -gnatVi -@emph{Validity checks for @code{in} mode parameters} -@cindex @option{-gnatVi} (@command{gcc}) -Arguments for parameters of mode @code{in} are validity checked in function +@emph{Validity checks for `in} mode parameters` + +Arguments for parameters of mode @cite{in} are validity checked in function and procedure calls at the point of call. +@end table + +@geindex -gnatVm (gcc) + + +@table @asis -@item -gnatVm -@emph{Validity checks for @code{in out} mode parameters.} -@cindex @option{-gnatVm} (@command{gcc}) -Arguments for parameters of mode @code{in out} are validity checked in -procedure calls at the point of call. The @code{'m'} here stands for +@item @code{-gnatVm} + +@emph{Validity checks for `in out} mode parameters.` + +Arguments for parameters of mode @cite{in out} are validity checked in +procedure calls at the point of call. The @cite{'m'} here stands for modify, since this concerns parameters that can be modified by the call. -Note that there is no specific option to test @code{out} parameters, +Note that there is no specific option to test @cite{out} parameters, but any reference within the subprogram will be tested in the usual manner, and if an invalid value is copied back, any reference to it will be subject to validity checking. +@end table + +@geindex -gnatVn (gcc) + + +@table @asis + +@item @code{-gnatVn} -@item -gnatVn @emph{No validity checks.} -@cindex @option{-gnatVn} (@command{gcc}) + This switch turns off all validity checking, including the default checking for case statements and left hand side subscripts. Note that the use of -the switch @option{-gnatp} suppresses all run-time checks, including -validity checks, and thus implies @option{-gnatVn}. When this switch -is used, it cancels any other @option{-gnatV} previously issued. +the switch @emph{-gnatp} suppresses all run-time checks, including +validity checks, and thus implies @emph{-gnatVn}. When this switch +is used, it cancels any other @emph{-gnatV} previously issued. + +@item @code{-gnatVo} -@item -gnatVo @emph{Validity checks for operator and attribute operands.} -@cindex @option{-gnatVo} (@command{gcc}) +.. index:: -gnatVo (gcc) + Arguments for predefined operators and attributes are validity checked. -This includes all operators in package @code{Standard}, -the shift operators defined as intrinsic in package @code{Interfaces} -and operands for attributes such as @code{Pos}. Checks are also made +This includes all operators in package @cite{Standard}, +the shift operators defined as intrinsic in package @cite{Interfaces} +and operands for attributes such as @cite{Pos}. Checks are also made on individual component values for composite comparisons, and on the expressions in type conversions and qualified expressions. Checks are -also made on explicit ranges using @samp{..} (e.g.@: slices, loops etc). +also made on explicit ranges using @code{..} (e.g., slices, loops etc). +@end table + +@geindex -gnatVp (gcc) + + +@table @asis + +@item @code{-gnatVp} -@item -gnatVp @emph{Validity checks for parameters.} -@cindex @option{-gnatVp} (@command{gcc}) + This controls the treatment of parameters within a subprogram (as opposed -to @option{-gnatVi} and @option{-gnatVm} which control validity testing +to @emph{-gnatVi} and @emph{-gnatVm} which control validity testing of parameters on a call. If either of these call options is used, then normally an assumption is made within a subprogram that the input arguments have been validity checking at the point of call, and do not need checking -again within a subprogram). If @option{-gnatVp} is set, then this assumption +again within a subprogram). If @emph{-gnatVp} is set, then this assumption is not made, and parameters are not assumed to be valid, so their validity will be checked (or rechecked) within the subprogram. +@end table + +@geindex -gnatVr (gcc) + + +@table @asis + +@item @code{-gnatVr} -@item -gnatVr @emph{Validity checks for function returns.} -@cindex @option{-gnatVr} (@command{gcc}) -The expression in @code{return} statements in functions is validity + +The expression in @cite{return} statements in functions is validity checked. +@end table + +@geindex -gnatVs (gcc) + + +@table @asis + +@item @code{-gnatVs} -@item -gnatVs @emph{Validity checks for subscripts.} -@cindex @option{-gnatVs} (@command{gcc}) + All subscripts expressions are checked for validity, whether they appear on the right side or left side (in default mode only left side subscripts are validity checked). +@end table + +@geindex -gnatVt (gcc) + + +@table @asis + +@item @code{-gnatVt} -@item -gnatVt @emph{Validity checks for tests.} -@cindex @option{-gnatVt} (@command{gcc}) -Expressions used as conditions in @code{if}, @code{while} or @code{exit} -statements are checked, as well as guard expressions in entry calls. +Expressions used as conditions in @cite{if}, @cite{while} or @cite{exit} +statements are checked, as well as guard expressions in entry calls. @end table -@noindent -The @option{-gnatV} switch may be followed by -a string of letters +The @emph{-gnatV} switch may be followed by a string of letters to turn on a series of validity checking options. -For example, -@option{-gnatVcr} +For example, @code{-gnatVcr} specifies that in addition to the default validity checking, copies and function return expressions are to be validity checked. -In order to make it easier -to specify the desired combination of effects, -the upper case letters @code{CDFIMORST} may +In order to make it easier to specify the desired combination of effects, +the upper case letters @cite{CDFIMORST} may be used to turn off the corresponding lower case option. -Thus -@option{-gnatVaM} -turns on all validity checking options except for -checking of @code{@b{in out}} procedure arguments. +Thus @code{-gnatVaM} turns on all validity checking options except for +checking of @cite{**in out**} procedure arguments. The specification of additional validity checking generates extra code (and -in the case of @option{-gnatVa} the code expansion can be substantial). +in the case of @emph{-gnatVa} the code expansion can be substantial). However, these additional checks can be very useful in detecting uninitialized variables, incorrect use of unchecked conversion, and other -errors leading to invalid values. The use of pragma @code{Initialize_Scalars} +errors leading to invalid values. The use of pragma @cite{Initialize_Scalars} is useful in conjunction with the extra validity checking, since this ensures that wherever possible uninitialized variables have invalid values. -See also the pragma @code{Validity_Checks} which allows modification of +See also the pragma @cite{Validity_Checks} which allows modification of the validity checking mode at the program source level, and also allows for temporary disabling of validity checks. -@node Style Checking +@node Style Checking,Run-Time Checks,Validity Checking,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat id18}@anchor{108}@anchor{gnat_ugn/building_executable_programs_with_gnat style-checking}@anchor{100} @subsection Style Checking -@findex Style checking -@noindent -The @option{-gnatyx} switch -@cindex @option{-gnaty} (@command{gcc}) -causes the compiler to + +@geindex Style checking + +@geindex -gnaty (gcc) + +The @emph{-gnatyx} switch causes the compiler to enforce specified style rules. A limited set of style rules has been used in writing the GNAT sources themselves. This switch allows user programs to activate all or some of these checks. If the source program fails a specified style check, an appropriate message is given, preceded by -the character sequence ``(style)''. This message does not prevent -successful compilation (unless the @option{-gnatwe} switch is used). +the character sequence '(style)'. This message does not prevent +successful compilation (unless the @emph{-gnatwe} switch is used). Note that this is by no means intended to be a general facility for checking arbitrary coding standards. It is simply an embedding of the @@ -6111,251 +12850,379 @@ style rules we have chosen for the GNAT sources. If you are starting a project which does not have established style standards, you may find it useful to adopt the entire set of GNAT coding standards, or some subset of them. -@ifclear FSFEDITION -If you already have an established set of coding -standards, then the selected style checking options may -indeed correspond to choices you have made, but for general checking -of an existing set of coding rules, you should look to the gnatcheck -tool, which is designed for that purpose. -@end ifclear - -The string @var{x} is a sequence of letters or digits + + +The string @cite{x} is a sequence of letters or digits indicating the particular style checks to be performed. The following checks are defined: -@table @option -@c !sort! -@item 0-9 +@geindex -gnaty[0-9] (gcc) + + +@table @asis + +@item @code{-gnaty0} + @emph{Specify indentation level.} + If a digit from 1-9 appears -in the string after @option{-gnaty} +in the string after @emph{-gnaty} then proper indentation is checked, with the digit indicating the indentation level required. A value of zero turns off this style check. The general style of required indentation is as specified by the examples in the Ada Reference Manual. Full line comments must be -aligned with the @code{--} starting on a column that is a multiple of +aligned with the @cite{--} starting on a column that is a multiple of the alignment level, or they may be aligned the same way as the following non-blank line (this is useful when full line comments appear in the middle of a statement, or they may be aligned with the source line on the previous non-blank line. +@end table + +@geindex -gnatya (gcc) + + +@table @asis + +@item @code{-gnatya} -@item a @emph{Check attribute casing.} -Attribute names, including the case of keywords such as @code{digits} + +Attribute names, including the case of keywords such as @cite{digits} used as attributes names, must be written in mixed case, that is, the initial letter and any letter following an underscore must be uppercase. All other letters must be lowercase. +@end table + +@geindex -gnatyA (gcc) + + +@table @asis + +@item @code{-gnatyA} -@item A @emph{Use of array index numbers in array attributes.} + When using the array attributes First, Last, Range, or Length, the index number must be omitted for one-dimensional arrays and is required for multi-dimensional arrays. +@end table + +@geindex -gnatyb (gcc) + + +@table @asis + +@item @code{-gnatyb} -@item b @emph{Blanks not allowed at statement end.} + Trailing blanks are not allowed at the end of statements. The purpose of this rule, together with h (no horizontal tabs), is to enforce a canonical format for the use of blanks to separate source tokens. +@end table + +@geindex -gnatyB (gcc) + + +@table @asis + +@item @code{-gnatyB} -@item B @emph{Check Boolean operators.} + The use of AND/OR operators is not permitted except in the cases of modular operands, array operands, and simple stand-alone boolean variables or -boolean constants. In all other cases @code{and then}/@code{or else} are +boolean constants. In all other cases @cite{and then}/@cite{or else} are required. +@end table + +@geindex -gnatyc (gcc) + + +@table @asis + +@item @code{-gnatyc} -@item c @emph{Check comments, double space.} + Comments must meet the following set of rules: -@itemize @bullet -@item -The ``@code{--}'' that starts the column must either start in column one, +@itemize * + +@item +The '@cite{--}' that starts the column must either start in column one, or else at least one blank must precede this sequence. -@item +@item Comments that follow other tokens on a line must have at least one blank -following the ``@code{--}'' at the start of the comment. +following the '@cite{--}' at the start of the comment. -@item +@item Full line comments must have at least two blanks following the -``@code{--}'' that starts the comment, with the following exceptions. +'@cite{--}' that starts the comment, with the following exceptions. -@item -A line consisting only of the ``@code{--}'' characters, possibly preceded +@item +A line consisting only of the '@cite{--}' characters, possibly preceded by blanks is permitted. -@item -A comment starting with ``@code{--x}'' where @code{x} is a special character +@item +A comment starting with '@cite{--x}' where @cite{x} is a special character is permitted. This allows proper processing of the output generated by specialized tools -including @command{gnatprep} (where ``@code{--!}'' is used) and the SPARK +including @emph{gnatprep} (where '@cite{--!}' is used) and the SPARK annotation -language (where ``@code{--#}'' is used). For the purposes of this rule, a +language (where '@cite{--#}' is used). For the purposes of this rule, a special character is defined as being in one of the ASCII ranges -@code{16#21#@dots{}16#2F#} or @code{16#3A#@dots{}16#3F#}. +@cite{16#21#...16#2F#} or @cite{16#3A#...16#3F#}. Note that this usage is not permitted -in GNAT implementation units (i.e., when @option{-gnatg} is used). +in GNAT implementation units (i.e., when @emph{-gnatg} is used). -@item +@item A line consisting entirely of minus signs, possibly preceded by blanks, is permitted. This allows the construction of box comments where lines of minus signs are used to form the top and bottom of the box. -@item -A comment that starts and ends with ``@code{--}'' is permitted as long as at -least one blank follows the initial ``@code{--}''. Together with the preceding +@item +A comment that starts and ends with '@cite{--}' is permitted as long as at +least one blank follows the initial '@cite{--}'. Together with the preceding rule, this allows the construction of box comments, as shown in the following example: -@smallexample + +@example --------------------------- -- This is a box comment -- -- with two text lines. -- --------------------------- -@end smallexample +@end example @end itemize +@end table + +@geindex -gnatyC (gcc) + + +@table @asis + +@item @code{-gnatyC} -@item C @emph{Check comments, single space.} -This is identical to @code{c} except that only one space -is required following the @code{--} of a comment instead of two. -@item d +This is identical to @cite{c} except that only one space +is required following the @cite{--} of a comment instead of two. +@end table + +@geindex -gnatyd (gcc) + + +@table @asis + +@item @code{-gnatyd} + @emph{Check no DOS line terminators present.} + All lines must be terminated by a single ASCII.LF character (in particular the DOS line terminator sequence CR/LF is not allowed). +@end table + +@geindex -gnatye (gcc) + + +@table @asis + +@item @code{-gnatye} -@item e @emph{Check end/exit labels.} -Optional labels on @code{end} statements ending subprograms and on -@code{exit} statements exiting named loops, are required to be present. -@item f +Optional labels on @cite{end} statements ending subprograms and on +@cite{exit} statements exiting named loops, are required to be present. +@end table + +@geindex -gnatyf (gcc) + + +@table @asis + +@item @code{-gnatyf} + @emph{No form feeds or vertical tabs.} + Neither form feeds nor vertical tab characters are permitted in the source text. +@end table + +@geindex -gnatyg (gcc) + + +@table @asis + +@item @code{-gnatyg} -@item g @emph{GNAT style mode.} + The set of style check switches is set to match that used by the GNAT sources. This may be useful when developing code that is eventually intended to be -incorporated into GNAT. Currently this is equivalent to @option{-gnatwydISux}) +incorporated into GNAT. Currently this is equivalent to @emph{-gnatwydISux}) but additional style switches may be added to this set in the future without advance notice. +@end table + +@geindex -gnatyh (gcc) + + +@table @asis + +@item @code{-gnatyh} -@item h @emph{No horizontal tabs.} + Horizontal tab characters are not permitted in the source text. Together with the b (no blanks at end of line) check, this enforces a canonical form for the use of blanks to separate source tokens. +@end table + +@geindex -gnatyi (gcc) + + +@table @asis + +@item @code{-gnatyi} -@item i @emph{Check if-then layout.} -The keyword @code{then} must appear either on the same -line as corresponding @code{if}, or on a line on its own, lined -up under the @code{if}. -@item I +The keyword @cite{then} must appear either on the same +line as corresponding @cite{if}, or on a line on its own, lined +up under the @cite{if}. +@end table + +@geindex -gnatyI (gcc) + + +@table @asis + +@item @code{-gnatyI} + @emph{check mode IN keywords.} -Mode @code{in} (the default mode) is not -allowed to be given explicitly. @code{in out} is fine, -but not @code{in} on its own. -@item k +Mode @cite{in} (the default mode) is not +allowed to be given explicitly. @cite{in out} is fine, +but not @cite{in} on its own. +@end table + +@geindex -gnatyk (gcc) + + +@table @asis + +@item @code{-gnatyk} + @emph{Check keyword casing.} + All keywords must be in lower case (with the exception of keywords -such as @code{digits} used as attribute names to which this check +such as @cite{digits} used as attribute names to which this check does not apply). +@end table + +@geindex -gnatyl (gcc) + + +@table @asis + +@item @code{-gnatyl} -@item l @emph{Check layout.} + Layout of statement and declaration constructs must follow the recommendations in the Ada Reference Manual, as indicated by the -form of the syntax rules. For example an @code{else} keyword must -be lined up with the corresponding @code{if} keyword. +form of the syntax rules. For example an @cite{else} keyword must +be lined up with the corresponding @cite{if} keyword. There are two respects in which the style rule enforced by this check option are more liberal than those in the Ada Reference Manual. First in the case of record declarations, it is permissible to put the -@code{record} keyword on the same line as the @code{type} keyword, and -then the @code{end} in @code{end record} must line up under @code{type}. +@cite{record} keyword on the same line as the @cite{type} keyword, and +then the @cite{end} in @cite{end record} must line up under @cite{type}. This is also permitted when the type declaration is split on two lines. For example, any of the following three layouts is acceptable: -@smallexample @c ada -@cartouche -@b{type} q @b{is} @b{record} +@example +type q is record a : integer; b : integer; -@b{end} @b{record}; +end record; -@b{type} q @b{is} - @b{record} +type q is + record a : integer; b : integer; - @b{end} @b{record}; + end record; -@b{type} q @b{is} - @b{record} +type q is + record a : integer; b : integer; -@b{end} @b{record}; - -@end cartouche -@end smallexample +end record; +@end example -@noindent Second, in the case of a block statement, a permitted alternative -is to put the block label on the same line as the @code{declare} or -@code{begin} keyword, and then line the @code{end} keyword up under +is to put the block label on the same line as the @cite{declare} or +@cite{begin} keyword, and then line the @cite{end} keyword up under the block label. For example both the following are permitted: -@smallexample @c ada -@cartouche -Block : @b{declare} +@example +Block : declare A : Integer := 3; -@b{begin} +begin Proc (A, A); -@b{end} Block; +end Block; Block : - @b{declare} + declare A : Integer := 3; - @b{begin} + begin Proc (A, A); - @b{end} Block; -@end cartouche -@end smallexample + end Block; +@end example -@noindent The same alternative format is allowed for loops. For example, both of the following are permitted: -@smallexample @c ada -@cartouche -Clear : @b{while} J < 10 @b{loop} +@example +Clear : while J < 10 loop A (J) := 0; -@b{end} @b{loop} Clear; +end loop Clear; Clear : - @b{while} J < 10 @b{loop} + while J < 10 loop A (J) := 0; - @b{end} @b{loop} Clear; -@end cartouche -@end smallexample + end loop Clear; +@end example +@end table + +@geindex -gnatyLnnn (gcc) + + +@table @asis + +@item @code{-gnatyL} -@item Lnnn @emph{Set maximum nesting level.} + The maximum level of nesting of constructs (including subprograms, loops, blocks, packages, and conditionals) may not exceed the given value -@option{nnn}. A value of zero disconnects this style check. +@emph{nnn}. A value of zero disconnects this style check. +@end table + +@geindex -gnatym (gcc) + + +@table @asis + +@item @code{-gnatym} -@item m @emph{Check maximum line length.} + The length of source lines must not exceed 79 characters, including any trailing blanks. The value of 79 allows convenient display on an 80 character wide device or window, allowing for possible special @@ -6363,161 +13230,285 @@ treatment of 80 character lines. Note that this count is of characters in the source text. This means that a tab character counts as one character in this count and a wide character sequence counts as a single character (however many bytes are needed in the encoding). +@end table + +@geindex -gnatyMnnn (gcc) + + +@table @asis + +@item @code{-gnatyM} -@item Mnnn @emph{Set maximum line length.} + The length of lines must not exceed the -given value @option{nnn}. The maximum value that can be specified is 32767. +given value @emph{nnn}. The maximum value that can be specified is 32767. If neither style option for setting the line length is used, then the default is 255. This also controls the maximum length of lexical elements, where the only restriction is that they must fit on a single line. +@end table + +@geindex -gnatyn (gcc) + + +@table @asis + +@item @code{-gnatyn} -@item n @emph{Check casing of entities in Standard.} + Any identifier from Standard must be cased to match the presentation in the Ada Reference Manual (for example, -@code{Integer} and @code{ASCII.NUL}). +@cite{Integer} and @cite{ASCII.NUL}). +@end table + +@geindex -gnatyN (gcc) + + +@table @asis + +@item @code{-gnatyN} -@item N @emph{Turn off all style checks.} + All style check options are turned off. +@end table + +@geindex -gnatyo (gcc) + + +@table @asis + +@item @code{-gnatyo} -@item o @emph{Check order of subprogram bodies.} + All subprogram bodies in a given scope -(e.g.@: a package body) must be in alphabetical order. The ordering +(e.g., a package body) must be in alphabetical order. The ordering rule uses normal Ada rules for comparing strings, ignoring casing of letters, except that if there is a trailing numeric suffix, then -the value of this suffix is used in the ordering (e.g.@: Junk2 comes +the value of this suffix is used in the ordering (e.g., Junk2 comes before Junk10). +@end table + +@geindex -gnatyO (gcc) + + +@table @asis + +@item @code{-gnatyO} -@item O @emph{Check that overriding subprograms are explicitly marked as such.} + The declaration of a primitive operation of a type extension that overrides an inherited operation must carry an overriding indicator. +@end table + +@geindex -gnatyp (gcc) + + +@table @asis + +@item @code{-gnatyp} -@item p @emph{Check pragma casing.} + Pragma names must be written in mixed case, that is, the initial letter and any letter following an underscore must be uppercase. All other letters must be lowercase. An exception is that SPARK_Mode is allowed as an alternative for Spark_Mode. +@end table + +@geindex -gnatyr (gcc) + + +@table @asis + +@item @code{-gnatyr} -@item r @emph{Check references.} + All identifier references must be cased in the same way as the corresponding declaration. No specific casing style is imposed on identifiers. The only requirement is for consistency of references with declarations. +@end table + +@geindex -gnatys (gcc) + + +@table @asis + +@item @code{-gnatys} -@item s @emph{Check separate specs.} -Separate declarations (``specs'') are required for subprograms (a + +Separate declarations ('specs') are required for subprograms (a body is not allowed to serve as its own declaration). The only exception is that parameterless library level procedures are not required to have a separate declaration. This exception covers the most frequent form of main program procedures. +@end table + +@geindex -gnatyS (gcc) + + +@table @asis + +@item @code{-gnatyS} + +@emph{Check no statements after then/else.} -@item S -@emph{Check no statements after @code{then}/@code{else}.} No statements are allowed -on the same line as a @code{then} or @code{else} keyword following the -keyword in an @code{if} statement. @code{or else} and @code{and then} are not -affected, and a special exception allows a pragma to appear after @code{else}. +on the same line as a @cite{then} or @cite{else} keyword following the +keyword in an @cite{if} statement. @cite{or else} and @cite{and then} are not +affected, and a special exception allows a pragma to appear after @cite{else}. +@end table + +@geindex -gnatyt (gcc) + + +@table @asis + +@item @code{-gnatyt} -@item t @emph{Check token spacing.} + The following token spacing rules are enforced: -@itemize @bullet -@item -The keywords @code{abs} and @code{not} must be followed by a space. +@itemize * -@item -The token @code{=>} must be surrounded by spaces. +@item +The keywords @cite{abs} and @cite{not} must be followed by a space. -@item -The token @code{<>} must be preceded by a space or a left parenthesis. +@item +The token @cite{=>} must be surrounded by spaces. -@item -Binary operators other than @code{**} must be surrounded by spaces. -There is no restriction on the layout of the @code{**} binary operator. +@item +The token @cite{<>} must be preceded by a space or a left parenthesis. -@item +@item +Binary operators other than @cite{**} must be surrounded by spaces. +There is no restriction on the layout of the @cite{**} binary operator. + +@item Colon must be surrounded by spaces. -@item +@item Colon-equal (assignment, initialization) must be surrounded by spaces. -@item +@item Comma must be the first non-blank character on the line, or be immediately preceded by a non-blank character, and must be followed by a space. -@item +@item If the token preceding a left parenthesis ends with a letter or digit, then a space must separate the two tokens. -@item -if the token following a right parenthesis starts with a letter or digit, then +@item +If the token following a right parenthesis starts with a letter or digit, then a space must separate the two tokens. -@item +@item A right parenthesis must either be the first non-blank character on a line, or it must be preceded by a non-blank character. -@item +@item A semicolon must not be preceded by a space, and must not be followed by a non-blank character. -@item +@item A unary plus or minus may not be followed by a space. -@item +@item A vertical bar must be surrounded by spaces. @end itemize Exactly one blank (and no other white space) must appear between -a @code{not} token and a following @code{in} token. +a @cite{not} token and a following @cite{in} token. +@end table + +@geindex -gnatyu (gcc) + + +@table @asis + +@item @code{-gnatyu} -@item u @emph{Check unnecessary blank lines.} + Unnecessary blank lines are not allowed. A blank line is considered unnecessary if it appears at the end of the file, or if more than one blank line occurs in sequence. +@end table + +@geindex -gnatyx (gcc) + + +@table @asis + +@item @code{-gnatyx} -@item x @emph{Check extra parentheses.} + Unnecessary extra level of parentheses (C-style) are not allowed -around conditions in @code{if} statements, @code{while} statements and -@code{exit} statements. +around conditions in @cite{if} statements, @cite{while} statements and +@cite{exit} statements. +@end table + +@geindex -gnatyy (gcc) + + +@table @asis + +@item @code{-gnatyy} -@item y @emph{Set all standard style check options} -This is equivalent to @code{gnaty3aAbcefhiklmnprst}, that is all checking -options enabled with the exception of @option{-gnatyB}, @option{-gnatyd}, -@option{-gnatyI}, @option{-gnatyLnnn}, @option{-gnatyo}, @option{-gnatyO}, -@option{-gnatyS}, @option{-gnatyu}, and @option{-gnatyx}. -@item - +This is equivalent to @cite{gnaty3aAbcefhiklmnprst}, that is all checking +options enabled with the exception of @emph{-gnatyB}, @emph{-gnatyd}, +@emph{-gnatyI}, @emph{-gnatyLnnn}, @emph{-gnatyo}, @emph{-gnatyO}, +@emph{-gnatyS}, @emph{-gnatyu}, and @emph{-gnatyx}. +@end table + +@geindex -gnaty- (gcc) + + +@table @asis + +@item @code{-gnaty-} + @emph{Remove style check options} + This causes any subsequent options in the string to act as canceling the corresponding style check option. To cancel maximum nesting level control, -use @option{L} parameter witout any integer value after that, because any -digit following @option{-} in the parameter string of the @option{-gnaty} +use @emph{L} parameter witout any integer value after that, because any +digit following @emph{-} in the parameter string of the @emph{-gnaty} option will be threated as canceling indentation check. The same is true -for @option{M} parameter. @option{y} and @option{N} parameters are not -allowed after @option{-}. +for @emph{M} parameter. @emph{y} and @emph{N} parameters are not +allowed after @emph{-}. +@end table + +@geindex -gnaty+ (gcc) + + +@table @asis + +@item @code{-gnaty+} + +@emph{Enable style check options} -@item + This causes any subsequent options in the string to enable the corresponding style check option. That is, it cancels the effect of a previous -, if any. - @end table -@noindent +@c end of switch description (leave this comment to ease automatic parsing for + +@c GPS + In the above rules, appearing in column one is always permitted, that is, counts as meeting either a requirement for a required preceding space, or as meeting a requirement for no preceding space. @@ -6526,51 +13517,60 @@ Appearing at the end of a line is also always permitted, that is, counts as meeting either a requirement for a following space, or as meeting a requirement for no following space. -@noindent If any of these style rules is violated, a message is generated giving details on the violation. The initial characters of such messages are -always ``@code{(style)}''. Note that these messages are treated as warning +always '@cite{(style)}'. Note that these messages are treated as warning messages, so they normally do not prevent the generation of an object -file. The @option{-gnatwe} switch can be used to treat warning messages, +file. The @emph{-gnatwe} switch can be used to treat warning messages, including style messages, as fatal errors. -The switch -@option{-gnaty} on its own (that is not +The switch @code{-gnaty} on its own (that is not followed by any letters or digits) is equivalent -to the use of @option{-gnatyy} as described above, that is all +to the use of @emph{-gnatyy} as described above, that is all built-in standard style check options are enabled. +The switch @code{-gnatyN} clears any previously set style checks. -The switch -@option{-gnatyN} -clears any previously set style checks. - -@node Run-Time Checks +@node Run-Time Checks,Using gcc for Syntax Checking,Style Checking,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat run-time-checks}@anchor{fe}@anchor{gnat_ugn/building_executable_programs_with_gnat id19}@anchor{109} @subsection Run-Time Checks -@cindex Division by zero -@cindex Access before elaboration -@cindex Checks, division by zero -@cindex Checks, access before elaboration -@cindex Checks, stack overflow checking -@noindent + +@geindex Division by zero + +@geindex Access before elaboration + +@geindex Checks +@geindex division by zero + +@geindex Checks +@geindex access before elaboration + +@geindex Checks +@geindex stack overflow checking + By default, the following checks are suppressed: integer overflow checks, stack overflow checks, and checks for access before elaboration on subprogram calls. All other checks, including range checks and array bounds checks, are turned on by default. The -following @command{gcc} switches refine this default behavior. - -@table @option -@c !sort! -@item -gnatp -@cindex @option{-gnatp} (@command{gcc}) -@cindex Suppressing checks -@cindex Checks, suppressing -@findex Suppress +following @emph{gcc} switches refine this default behavior. + +@geindex -gnatp (gcc) + + +@table @asis + +@item @code{-gnatp} + +@geindex Suppressing checks + +@geindex Checks +@geindex suppressing + This switch causes the unit to be compiled -as though @code{pragma Suppress (All_checks)} +as though @cite{pragma Suppress (All_checks)} had been present in the source. Validity checks are also eliminated (in -other words @option{-gnatp} also implies @option{-gnatVn}. +other words @emph{-gnatp} also implies @emph{-gnatVn}. Use this switch to improve the performance of the code at the expense of safety in the presence of invalid data or program bugs. @@ -6580,7 +13580,7 @@ required, to omit the checking code. If the run-time cost of the checking code is zero or near-zero, the compiler will generate it even if checks are suppressed. In particular, if the compiler can prove that a certain check will necessarily fail, it will generate code to -do an unconditional ``raise'', even if checks are suppressed. The +do an unconditional 'raise', even if checks are suppressed. The compiler warns in this case. Another case in which checks may not be eliminated is when they are embedded in certain run time routines such as math library routines. @@ -6599,60 +13599,85 @@ execution if that assumption is wrong. The checks subject to suppression include all the checks defined by the Ada standard, the additional implementation defined checks -@code{Alignment_Check}, -@code{Duplicated_Tag_Check}, @code{Predicate_Check}, and -@code{Validity_Check}, as well as any checks introduced using -@code{pragma Check_Name}. Note that @code{Atomic_Synchronization} +@cite{Alignment_Check}, +@cite{Duplicated_Tag_Check}, @cite{Predicate_Check}, and +@cite{Validity_Check}, as well as any checks introduced using +@cite{pragma Check_Name}. Note that @cite{Atomic_Synchronization} is not automatically suppressed by use of this option. If the code depends on certain checks being active, you can use -pragma @code{Unsuppress} either as a configuration pragma or as +pragma @cite{Unsuppress} either as a configuration pragma or as a local pragma to make sure that a specified check is performed -even if @option{gnatp} is specified. - -The @option{-gnatp} switch has no effect if a subsequent -@option{-gnat-p} switch appears. - -@item -gnat-p -@cindex @option{-gnat-p} (@command{gcc}) -@cindex Suppressing checks -@cindex Checks, suppressing -@findex Suppress -This switch cancels the effect of a previous @option{gnatp} switch. - -@item -gnato?? -@cindex @option{-gnato??} (@command{gcc}) -@cindex Overflow checks -@cindex Overflow mode -@cindex Check, overflow +even if @emph{gnatp} is specified. + +The @emph{-gnatp} switch has no effect if a subsequent +@emph{-gnat-p} switch appears. +@end table + +@geindex -gnat-p (gcc) + +@geindex Suppressing checks + +@geindex Checks +@geindex suppressing + +@geindex Suppress + + +@table @asis + +@item @code{-gnat-p} + +This switch cancels the effect of a previous @emph{gnatp} switch. +@end table + +@geindex -gnato?? (gcc) + +@geindex Overflow checks + +@geindex Overflow mode + +@geindex Check +@geindex overflow + + +@table @asis + +@item @code{-gnato??} + This switch controls the mode used for computing intermediate arithmetic integer operations, and also enables overflow checking. For a full description of overflow mode and checking control, see -the ``Overflow Check Handling in GNAT'' appendix in this +the 'Overflow Check Handling in GNAT' appendix in this User's Guide. Overflow checks are always enabled by this switch. The argument controls the mode, using the codes -@itemize -@item 1 = STRICT + +@table @asis + +@item @emph{1 = STRICT} + In STRICT mode, intermediate operations are always done using the base type, and overflow checking ensures that the result is within the base type range. -@item 2 = MINIMIZED +@item @emph{2 = MINIMIZED} + In MINIMIZED mode, overflows in intermediate operations are avoided where possible by using a larger integer type for the computation -(typically @code{Long_Long_Integer}). Overflow checking ensures that +(typically @cite{Long_Long_Integer}). Overflow checking ensures that the result fits in this larger integer type. -@item 3 = ELIMINATED +@item @emph{3 = ELIMINATED} + In ELIMINATED mode, overflows in intermediate operations are avoided by using multi-precision arithmetic. In this case, overflow checking has no effect on intermediate operations (since overflow is impossible). -@end itemize +@end table -If two digits are present after @option{-gnato} then the first digit +If two digits are present after @emph{-gnato} then the first digit sets the mode for expressions outside assertions, and the second digit sets the mode for expressions within assertions. Here assertions is used in the technical sense (which includes for example precondition and @@ -6663,13 +13688,14 @@ expressions within and outside assertion expressions. If no digits are present, the default is to enable overflow checks and set STRICT mode for both kinds of expressions. This is compatible -with the use of @option{-gnato} in previous versions of GNAT. +with the use of @emph{-gnato} in previous versions of GNAT. + +@geindex Machine_Overflows -@findex Machine_Overflows -Note that the @option{-gnato??} switch does not affect the code generated +Note that the @emph{-gnato??} switch does not affect the code generated for any floating-point operations; it applies only to integer semantics. -For floating-point, @value{EDITION} has the @code{Machine_Overflows} -attribute set to @code{False} and the normal mode of operation is to +For floating-point, GNAT has the @cite{Machine_Overflows} +attribute set to @cite{False} and the normal mode of operation is to generate IEEE NaN and infinite values on overflow or invalid operations (such as dividing 0.0 by 0.0). @@ -6681,99 +13707,128 @@ subscript), or a wild jump (from an out of range case value). Overflow checking is also quite expensive in time and space, since in general it requires the use of double length arithmetic. -Note again that the default is @option{-gnato00}, +Note again that the default is @emph{-gnato00}, so overflow checking is not performed in default mode. This means that out of -the box, with the default settings, @value{EDITION} does not do all the checks +the box, with the default settings, GNAT does not do all the checks expected from the language description in the Ada Reference Manual. If you want all constraint checks to be performed, as described in this Manual, -then you must explicitly use the @option{-gnato??} -switch either on the @command{gnatmake} or @command{gcc} command. +then you must explicitly use the @emph{-gnato??} +switch either on the @emph{gnatmake} or @emph{gcc} command. +@end table + +@geindex -gnatE (gcc) + +@geindex Elaboration checks + +@geindex Check +@geindex elaboration + + +@table @asis + +@item @code{-gnatE} -@item -gnatE -@cindex @option{-gnatE} (@command{gcc}) -@cindex Elaboration checks -@cindex Check, elaboration Enables dynamic checks for access-before-elaboration on subprogram calls and generic instantiations. -Note that @option{-gnatE} is not necessary for safety, because in the +Note that @emph{-gnatE} is not necessary for safety, because in the default mode, GNAT ensures statically that the checks would not fail. For full details of the effect and use of this switch, -@xref{Compiling with gcc}. +@ref{1e,,Compiling with gcc}. +@end table + +@geindex -fstack-check (gcc) + +@geindex Stack Overflow Checking + +@geindex Checks +@geindex stack overflow checking + + +@table @asis + +@item @code{-fstack-check} -@item -fstack-check -@cindex @option{-fstack-check} (@command{gcc}) -@cindex Stack Overflow Checking -@cindex Checks, stack overflow checking Activates stack overflow checking. For full details of the effect and use of -this switch see @ref{Stack Overflow Checking}. +this switch see @ref{f9,,Stack Overflow Checking}. @end table -@findex Unsuppress -@noindent +@geindex Unsuppress + The setting of these switches only controls the default setting of the -checks. You may modify them using either @code{Suppress} (to remove -checks) or @code{Unsuppress} (to add back suppressed checks) pragmas in +checks. You may modify them using either @cite{Suppress} (to remove +checks) or @cite{Unsuppress} (to add back suppressed checks) pragmas in the program source. -@node Using gcc for Syntax Checking -@subsection Using @command{gcc} for Syntax Checking -@table @option -@item -gnats -@cindex @option{-gnats} (@command{gcc}) +@node Using gcc for Syntax Checking,Using gcc for Semantic Checking,Run-Time Checks,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat id20}@anchor{10a}@anchor{gnat_ugn/building_executable_programs_with_gnat using-gcc-for-syntax-checking}@anchor{10b} +@subsection Using @emph{gcc} for Syntax Checking + + +@geindex -gnats (gcc) + -@noindent -The @code{s} stands for ``syntax''. +@table @asis + +@item @code{-gnats} + +The @cite{s} stands for 'syntax'. Run GNAT in syntax checking only mode. For example, the command -@smallexample +@example $ gcc -c -gnats x.adb -@end smallexample +@end example -@noindent -compiles file @file{x.adb} in syntax-check-only mode. You can check a +compiles file @code{x.adb} in syntax-check-only mode. You can check a series of files in a single command , and can use wild cards to specify such a group of files. -Note that you must specify the @option{-c} (compile -only) flag in addition to the @option{-gnats} flag. -. -You may use other switches in conjunction with @option{-gnats}. In -particular, @option{-gnatl} and @option{-gnatv} are useful to control the +Note that you must specify the @emph{-c} (compile +only) flag in addition to the @emph{-gnats} flag. + +You may use other switches in conjunction with @emph{-gnats}. In +particular, @emph{-gnatl} and @emph{-gnatv} are useful to control the format of any generated error messages. When the source file is empty or contains only empty lines and/or comments, the output is a warning: -@smallexample +@example $ gcc -c -gnats -x ada toto.txt toto.txt:1:01: warning: empty file, contains no compilation units $ -@end smallexample +@end example Otherwise, the output is simply the error messages, if any. No object file or ALI file is generated by a syntax-only compilation. Also, no units other -than the one specified are accessed. For example, if a unit @code{X} -@code{with}'s a unit @code{Y}, compiling unit @code{X} in syntax +than the one specified are accessed. For example, if a unit @cite{X} +@emph{with}s a unit @cite{Y}, compiling unit @cite{X} in syntax check only mode does not access the source file containing unit -@code{Y}. +@cite{Y}. + +@geindex Multiple units +@geindex syntax checking -@cindex Multiple units, syntax checking Normally, GNAT allows only a single unit in a source file. However, this restriction does not apply in syntax-check-only mode, and it is possible to check a file containing multiple compilation units concatenated -together. This is primarily used by the @code{gnatchop} utility -(@pxref{Renaming Files with gnatchop}). +together. This is primarily used by the @cite{gnatchop} utility +(@ref{38,,Renaming Files with gnatchop}). @end table -@node Using gcc for Semantic Checking -@subsection Using @command{gcc} for Semantic Checking -@table @option -@item -gnatc -@cindex @option{-gnatc} (@command{gcc}) +@node Using gcc for Semantic Checking,Compiling Different Versions of Ada,Using gcc for Syntax Checking,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat id21}@anchor{10c}@anchor{gnat_ugn/building_executable_programs_with_gnat using-gcc-for-semantic-checking}@anchor{10d} +@subsection Using @emph{gcc} for Semantic Checking + + +@geindex -gnatc (gcc) + -@noindent -The @code{c} stands for ``check''. +@table @asis + +@item @code{-gnatc} + +The @cite{c} stands for 'check'. Causes the compiler to operate in semantic check mode, with full checking for all illegalities specified in the Ada Reference Manual, but without generation of any object code @@ -6782,20 +13837,22 @@ Ada Reference Manual, but without generation of any object code Because dependent files must be accessed, you must follow the GNAT semantic restrictions on file structuring to operate in this mode: -@itemize @bullet -@item + +@itemize * + +@item The needed source files must be accessible -(@pxref{Search Paths and the Run-Time Library (RTL)}). +(see @ref{8e,,Search Paths and the Run-Time Library (RTL)}). -@item +@item Each file must contain only one compilation unit. -@item -The file name and unit name must match (@pxref{File Naming Rules}). +@item +The file name and unit name must match (@ref{54,,File Naming Rules}). @end itemize The output consists of error messages as appropriate. No object file is -generated. An @file{ALI} file is generated for use in the context of +generated. An @code{ALI} file is generated for use in the context of cross-reference tools, but this file is marked as not being suitable for binding (since no object file is generated). The checking corresponds exactly to the notion of @@ -6806,28 +13863,34 @@ units that would not normally be compiled (subunits, and specifications where a separate body is present). @end table -@node Compiling Different Versions of Ada +@node Compiling Different Versions of Ada,Character Set Control,Using gcc for Semantic Checking,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat compiling-different-versions-of-ada}@anchor{6}@anchor{gnat_ugn/building_executable_programs_with_gnat id22}@anchor{10e} @subsection Compiling Different Versions of Ada -@noindent + The switches described in this section allow you to explicitly specify the version of the Ada language that your programs are written in. The default mode is Ada 2012, but you can also specify Ada 95, Ada 2005 mode, or indicate Ada 83 compatibility mode. -@table @option -@cindex Compatibility with Ada 83 +@geindex Compatibility with Ada 83 -@item -gnat83 (Ada 83 Compatibility Mode) -@cindex @option{-gnat83} (@command{gcc}) -@cindex ACVC, Ada 83 tests -@cindex Ada 83 mode +@geindex -gnat83 (gcc) + +@geindex ACVC +@geindex Ada 83 tests + +@geindex Ada 83 mode + + +@table @asis + +@item @code{-gnat83 (Ada 83 Compatibility Mode)} -@noindent Although GNAT is primarily an Ada 95 / Ada 2005 compiler, this switch specifies that the program is to be compiled in Ada 83 mode. With -@option{-gnat83}, GNAT rejects most post-Ada 83 extensions and applies Ada 83 +@emph{-gnat83}, GNAT rejects most post-Ada 83 extensions and applies Ada 83 semantics where this can be done easily. It is not possible to guarantee this switch does a perfect job; some subtle tests, such as are @@ -6837,159 +13900,285 @@ Nevertheless, this switch may be useful in some circumstances, for example where, due to contractual reasons, existing code needs to be maintained using only Ada 83 features. -With few exceptions (most notably the need to use @code{<>} on -@cindex Generic formal parameters +With few exceptions (most notably the need to use @cite{<>} on +.. index:: Generic formal parameters + unconstrained generic formal parameters, the use of the new Ada 95 / Ada 2005 reserved words, and the use of packages with optional bodies), it is not necessary to specify the -@option{-gnat83} switch when compiling Ada 83 programs, because, with rare +@emph{-gnat83} switch when compiling Ada 83 programs, because, with rare exceptions, Ada 95 and Ada 2005 are upwardly compatible with Ada 83. Thus a correct Ada 83 program is usually also a correct program -in these later versions of the language standard. -For further information, please refer to @ref{Compatibility and Porting Guide}. +in these later versions of the language standard. For further information +please refer to the @cite{Compatibility_and_Porting_Guide} chapter in the +@cite{GNAT Reference Manual}. +@end table -@item -gnat95 (Ada 95 mode) -@cindex @option{-gnat95} (@command{gcc}) -@cindex Ada 95 mode +@geindex -gnat95 (gcc) + +@geindex Ada 95 mode + + +@table @asis + +@item @code{-gnat95} (Ada 95 mode) -@noindent This switch directs the compiler to implement the Ada 95 version of the language. Since Ada 95 is almost completely upwards compatible with Ada 83, Ada 83 programs may generally be compiled using -this switch (see the description of the @option{-gnat83} switch for further +this switch (see the description of the @emph{-gnat83} switch for further information about Ada 83 mode). If an Ada 2005 program is compiled in Ada 95 mode, uses of the new Ada 2005 features will cause error messages or warnings. This switch also can be used to cancel the effect of a previous -@option{-gnat83}, @option{-gnat05/2005}, or @option{-gnat12/2012} +@emph{-gnat83}, @emph{-gnat05/2005}, or @emph{-gnat12/2012} switch earlier in the command line. +@end table + +@geindex -gnat05 (gcc) + +@geindex -gnat2005 (gcc) -@item -gnat05 or -gnat2005 (Ada 2005 mode) -@cindex @option{-gnat05} (@command{gcc}) -@cindex @option{-gnat2005} (@command{gcc}) -@cindex Ada 2005 mode +@geindex Ada 2005 mode + + +@table @asis + +@item @code{-gnat05} or @code{-gnat2005} (Ada 2005 mode) -@noindent This switch directs the compiler to implement the Ada 2005 version of the language, as documented in the official Ada standards document. Since Ada 2005 is almost completely upwards compatible with Ada 95 (and thus also with Ada 83), Ada 83 and Ada 95 programs may generally be compiled using this switch (see the description of the -@option{-gnat83} and @option{-gnat95} switches for further +@emph{-gnat83} and @emph{-gnat95} switches for further information). +@end table + +@geindex -gnat12 (gcc) + +@geindex -gnat2012 (gcc) + +@geindex Ada 2012 mode -@item -gnat12 or -gnat2012 (Ada 2012 mode) -@cindex @option{-gnat12} (@command{gcc}) -@cindex @option{-gnat2012} (@command{gcc}) -@cindex Ada 2012 mode -@noindent +@table @asis + +@item @code{-gnat12} or @code{-gnat2012} (Ada 2012 mode) + This switch directs the compiler to implement the Ada 2012 version of the language (also the default). Since Ada 2012 is almost completely upwards compatible with Ada 2005 (and thus also with Ada 83, and Ada 95), Ada 83 and Ada 95 programs may generally be compiled using this switch (see the description of the -@option{-gnat83}, @option{-gnat95}, and @option{-gnat05/2005} switches +@emph{-gnat83}, @emph{-gnat95}, and @emph{-gnat05/2005} switches for further information). +@end table + +@geindex -gnatX (gcc) + +@geindex Ada language extensions + +@geindex GNAT extensions + -@item -gnatX (Enable GNAT Extensions) -@cindex @option{-gnatX} (@command{gcc}) -@cindex Ada language extensions -@cindex GNAT extensions +@table @asis + +@item @code{-gnatX} (Enable GNAT Extensions) -@noindent This switch directs the compiler to implement the latest version of the language (currently Ada 2012) and also to enable certain GNAT implementation extensions that are not part of any Ada standard. For a full list of these extensions, see the GNAT reference manual. - @end table -@node Character Set Control +@node Character Set Control,File Naming Control,Compiling Different Versions of Ada,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat id23}@anchor{10f}@anchor{gnat_ugn/building_executable_programs_with_gnat character-set-control}@anchor{4a} @subsection Character Set Control -@table @option -@item -gnati@var{c} -@cindex @option{-gnati} (@command{gcc}) -@noindent + +@geindex -gnati (gcc) + + +@table @asis + +@item @code{-gnati@emph{c}} + Normally GNAT recognizes the Latin-1 character set in source program identifiers, as described in the Ada Reference Manual. This switch causes -GNAT to recognize alternate character sets in identifiers. @var{c} is a +GNAT to recognize alternate character sets in identifiers. @cite{c} is a single character indicating the character set, as follows: -@table @code -@item 1 + +@multitable {xxxxxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item + +@emph{1} + +@tab + ISO 8859-1 (Latin-1) identifiers -@item 2 +@item + +@emph{2} + +@tab + ISO 8859-2 (Latin-2) letters allowed in identifiers -@item 3 +@item + +@emph{3} + +@tab + ISO 8859-3 (Latin-3) letters allowed in identifiers -@item 4 +@item + +@emph{4} + +@tab + ISO 8859-4 (Latin-4) letters allowed in identifiers -@item 5 +@item + +@emph{5} + +@tab + ISO 8859-5 (Cyrillic) letters allowed in identifiers -@item 9 +@item + +@emph{9} + +@tab + ISO 8859-15 (Latin-9) letters allowed in identifiers -@item p +@item + +@emph{p} + +@tab + IBM PC letters (code page 437) allowed in identifiers -@item 8 +@item + +@emph{8} + +@tab + IBM PC letters (code page 850) allowed in identifiers -@item f +@item + +@emph{f} + +@tab + Full upper-half codes allowed in identifiers -@item n +@item + +@emph{n} + +@tab + No upper-half codes allowed in identifiers -@item w +@item + +@emph{w} + +@tab + Wide-character codes (that is, codes greater than 255) allowed in identifiers -@end table -@xref{Foreign Language Representation}, for full details on the +@end multitable + + +See @ref{40,,Foreign Language Representation} for full details on the implementation of these character sets. +@end table + +@geindex -gnatW (gcc) + + +@table @asis + +@item @code{-gnatW@emph{e}} -@item -gnatW@var{e} -@cindex @option{-gnatW} (@command{gcc}) Specify the method of encoding for wide characters. -@var{e} is one of the following: +@cite{e} is one of the following: -@table @code -@item h +@multitable {xxxxxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item + +@emph{h} + +@tab + Hex encoding (brackets coding also recognized) -@item u +@item + +@emph{u} + +@tab + Upper half encoding (brackets encoding also recognized) -@item s +@item + +@emph{s} + +@tab + Shift/JIS encoding (brackets encoding also recognized) -@item e +@item + +@emph{e} + +@tab + EUC encoding (brackets encoding also recognized) -@item 8 +@item + +@emph{8} + +@tab + UTF-8 encoding (brackets encoding also recognized) -@item b +@item + +@emph{b} + +@tab + Brackets encoding only (default value) -@end table + +@end multitable + + For full details on these encoding -methods see @ref{Wide_Character Encodings}. +methods see @ref{50,,Wide_Character Encodings}. Note that brackets coding is always accepted, even if one of the other -options is specified, so for example @option{-gnatW8} specifies that both +options is specified, so for example @emph{-gnatW8} specifies that both brackets and UTF-8 encodings will be recognized. The units that are with'ed directly or indirectly will be scanned using the specified representation scheme, and so if one of the non-brackets scheme is @@ -7002,7 +14191,7 @@ Note that brackets encoding only applies to program text. Within comments, brackets are considered to be normal graphic characters, and bracket sequences are never recognized as wide characters. -If no @option{-gnatW?} parameter is present, then the default +If no @emph{-gnatW?} parameter is present, then the default representation is normally Brackets encoding only. However, if the first three characters of the file are 16#EF# 16#BB# 16#BF# (the standard byte order mark or BOM for UTF-8), then these three characters are @@ -7012,10 +14201,9 @@ Note that the wide character representation that is specified (explicitly or by default) for the main program also acts as the default encoding used for Wide_Text_IO files if not specifically overridden by a WCEM form parameter. - @end table -When no @option{-gnatW?} is specified, then characters (other than wide +When no @emph{-gnatW?} is specified, then characters (other than wide characters represented using brackets notation) are treated as 8-bit Latin-1 codes. The codes recognized are the Latin-1 graphic characters, and ASCII format effectors (CR, LF, HT, VT). Other lower half control @@ -7035,125 +14223,204 @@ UTF-8 encoding for comments are accepted in default mode, providing that the comments are ended by an appropriate (CR, or CR/LF, or LF) line terminator. This is a common mode for many programs with foreign language comments. -@node File Naming Control +@node File Naming Control,Subprogram Inlining Control,Character Set Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat file-naming-control}@anchor{110}@anchor{gnat_ugn/building_executable_programs_with_gnat id24}@anchor{111} @subsection File Naming Control -@table @option -@item -gnatk@var{n} -@cindex @option{-gnatk} (@command{gcc}) -Activates file name ``krunching''. @var{n}, a decimal integer in the range + +@geindex -gnatk (gcc) + + +@table @asis + +@item @code{-gnatk@emph{n}} + +Activates file name 'krunching'. @cite{n}, a decimal integer in the range 1-999, indicates the maximum allowable length of a file name (not -including the @file{.ads} or @file{.adb} extension). The default is not +including the @code{.ads} or @code{.adb} extension). The default is not to enable file name krunching. -For the source file naming rules, @xref{File Naming Rules}. +For the source file naming rules, @ref{54,,File Naming Rules}. @end table -@node Subprogram Inlining Control +@node Subprogram Inlining Control,Auxiliary Output Control,File Naming Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat subprogram-inlining-control}@anchor{112}@anchor{gnat_ugn/building_executable_programs_with_gnat id25}@anchor{113} @subsection Subprogram Inlining Control -@table @option -@c !sort! -@item -gnatn[12] -@cindex @option{-gnatn} (@command{gcc}) -The @code{n} here is intended to suggest the first syllable of the -word ``inline''. -GNAT recognizes and processes @code{Inline} pragmas. However, for the + +@geindex -gnatn (gcc) + + +@table @asis + +@item @code{-gnatn[12]} + +The @cite{n} here is intended to suggest the first syllable of the +word 'inline'. +GNAT recognizes and processes @cite{Inline} pragmas. However, for the inlining to actually occur, optimization must be enabled and, in order -to enable inlining of subprograms specified by pragma @code{Inline}, +to enable inlining of subprograms specified by pragma @cite{Inline}, you must also specify this switch. In the absence of this switch, GNAT does not attempt inlining and does not need to access the bodies of -subprograms for which @code{pragma Inline} is specified if they are not +subprograms for which @cite{pragma Inline} is specified if they are not in the current unit. You can optionally specify the inlining level: 1 for moderate inlining across modules, which is a good compromise between compilation times and performances at run time, or 2 for full inlining across modules, which may bring about longer compilation times. If no inlining level is specified, the compiler will -pick it based on the optimization level: 1 for @option{-O1}, @option{-O2} or -@option{-Os} and 2 for @option{-O3}. +pick it based on the optimization level: 1 for @emph{-O1}, @emph{-O2} or +@emph{-Os} and 2 for @emph{-O3}. If you specify this switch the compiler will access these bodies, creating an extra source dependency for the resulting object file, and where possible, the call will be inlined. For further details on when inlining is possible -see @ref{Inlining of Subprograms}. +see @ref{114,,Inlining of Subprograms}. +@end table + +@geindex -gnatN (gcc) + + +@table @asis + +@item @code{-gnatN} -@item -gnatN -@cindex @option{-gnatN} (@command{gcc}) This switch activates front-end inlining which also generates additional dependencies. When using a gcc-based back end (in practice this means using any version of GNAT other than the JGNAT, .NET or GNAAMP versions), then the use of -@option{-gnatN} is deprecated, and the use of @option{-gnatn} is preferred. +@emph{-gnatN} is deprecated, and the use of @emph{-gnatn} is preferred. Historically front end inlining was more extensive than the gcc back end inlining, but that is no longer the case. @end table -@node Auxiliary Output Control +@node Auxiliary Output Control,Debugging Control,Subprogram Inlining Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat auxiliary-output-control}@anchor{115}@anchor{gnat_ugn/building_executable_programs_with_gnat id26}@anchor{116} @subsection Auxiliary Output Control -@table @option -@item -gnatt -@cindex @option{-gnatt} (@command{gcc}) -@cindex Writing internal trees -@cindex Internal trees, writing to file + +@geindex -gnatt (gcc) + +@geindex Writing internal trees + +@geindex Internal trees +@geindex writing to file + + +@table @asis + +@item @code{-gnatt} + Causes GNAT to write the internal tree for a unit to a file (with the -extension @file{.adt}. +extension @code{.adt}. This not normally required, but is used by separate analysis tools. Typically these tools do the necessary compilations automatically, so you should not have to specify this switch in normal operation. -Note that the combination of switches @option{-gnatct} +Note that the combination of switches @emph{-gnatct} generates a tree in the form required by ASIS applications. +@end table -@item -gnatu -@cindex @option{-gnatu} (@command{gcc}) -Print a list of units required by this compilation on @file{stdout}. +@geindex -gnatu (gcc) + + +@table @asis + +@item @code{-gnatu} + +Print a list of units required by this compilation on @code{stdout}. The listing includes all units on which the unit being compiled depends either directly or indirectly. +@end table + +@geindex -pass-exit-codes (gcc) + -@item -pass-exit-codes -@cindex @option{-pass-exit-codes} (@command{gcc}) -If this switch is not used, the exit code returned by @command{gcc} when +@table @asis + +@item @code{-pass-exit-codes} + +If this switch is not used, the exit code returned by @emph{gcc} when compiling multiple files indicates whether all source files have been successfully used to generate object files or not. -When @option{-pass-exit-codes} is used, @command{gcc} exits with an extended +When @emph{-pass-exit-codes} is used, @emph{gcc} exits with an extended exit status and allows an integrated development environment to better react to a compilation failure. Those exit status are: -@table @asis -@item 5 + +@multitable {xxxxxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item + +@emph{5} + +@tab + There was an error in at least one source file. -@item 3 + +@item + +@emph{3} + +@tab + At least one source file did not generate an object file. -@item 2 + +@item + +@emph{2} + +@tab + The compiler died unexpectedly (internal error for example). -@item 0 + +@item + +@emph{0} + +@tab + An object file has been generated for every source file. -@end table + +@end multitable + @end table -@node Debugging Control +@node Debugging Control,Exception Handling Control,Auxiliary Output Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat debugging-control}@anchor{117}@anchor{gnat_ugn/building_executable_programs_with_gnat id27}@anchor{118} @subsection Debugging Control -@table @option -@c !sort! -@cindex Debugging options -@item -gnatd@var{x} -@cindex @option{-gnatd} (@command{gcc}) -Activate internal debugging switches. @var{x} is a letter or digit, or + +@quotation + +@geindex Debugging options +@end quotation + +@geindex -gnatd (gcc) + + +@table @asis + +@item @code{-gnatd@emph{x}} + +Activate internal debugging switches. @cite{x} is a letter or digit, or string of letters or digits, which specifies the type of debugging outputs desired. Normally these are used only for internal development or system debugging purposes. You can find full documentation for these -switches in the body of the @code{Debug} unit in the compiler source -file @file{debug.adb}. +switches in the body of the @cite{Debug} unit in the compiler source +file @code{debug.adb}. +@end table + +@geindex -gnatG (gcc) + + +@table @asis + +@item @code{-gnatG[=@emph{nn}]} -@item -gnatG[=nn] -@cindex @option{-gnatG} (@command{gcc}) This switch causes the compiler to generate auxiliary output containing a pseudo-source listing of the generated expanded code. Like most Ada compilers, GNAT works by first transforming the high level Ada code into @@ -7162,12 +14429,12 @@ into calls to the tasking run-time routines. A unique capability of GNAT is to list this expanded code in a form very close to normal Ada source. This is very useful in understanding the implications of various Ada usage on the efficiency of the generated code. There are many cases in -Ada (e.g.@: the use of controlled types), where simple Ada statements can -generate a lot of run-time code. By using @option{-gnatG} you can identify +Ada (e.g., the use of controlled types), where simple Ada statements can +generate a lot of run-time code. By using @emph{-gnatG} you can identify these cases, and consider whether it may be desirable to modify the coding approach to improve efficiency. -The optional parameter @code{nn} if present after -gnatG specifies an +The optional parameter @cite{nn} if present after -gnatG specifies an alternative maximum line length that overrides the normal default of 72. This value is in the range 40-999999, values less than 40 being silently reset to 40. The equal sign is optional. @@ -7177,171 +14444,225 @@ easily understood by an Ada programmer. The following special syntactic additions correspond to low level features used in the generated code that do not have any exact analogies in pure Ada source form. The following is a partial list of these special constructions. See the spec -of package @code{Sprint} in file @file{sprint.ads} for a full list. +of package @cite{Sprint} in file @code{sprint.ads} for a full list. -If the switch @option{-gnatL} is used in conjunction with -@cindex @option{-gnatL} (@command{gcc}) -@option{-gnatG}, then the original source lines are interspersed +@geindex -gnatL (gcc) + +If the switch @emph{-gnatL} is used in conjunction with +@emph{-gnatG}, then the original source lines are interspersed in the expanded source (as comment lines with the original line number). -@table @code -@item new @var{xxx} @r{[}storage_pool = @var{yyy}@r{]} + +@table @asis + +@item @code{new @emph{xxx} [storage_pool = @emph{yyy}]} + Shows the storage pool being used for an allocator. -@item at end @var{procedure-name}; +@item @code{at end @emph{procedure-name};} + Shows the finalization (cleanup) procedure for a scope. -@item (if @var{expr} then @var{expr} else @var{expr}) -Conditional expression equivalent to the @code{x?y:z} construction in C. +@item @code{(if @emph{expr} then @emph{expr} else @emph{expr})} + +Conditional expression equivalent to the @cite{x?y:z} construction in C. + +@item @code{@emph{target}^(@emph{source})} -@item @var{target}^(@var{source}) A conversion with floating-point truncation instead of rounding. -@item @var{target}?(@var{source}) +@item @code{@emph{target}?(@emph{source})} + A conversion that bypasses normal Ada semantic checking. In particular enumeration types and fixed-point types are treated simply as integers. -@item @var{target}?^(@var{source}) +@item @code{@emph{target}?^(@emph{source})} + Combines the above two cases. +@end table + +@code{@emph{x} #/ @emph{y}} + +@code{@emph{x} #mod @emph{y}} + +@code{@emph{x} # @emph{y}} + + +@table @asis + +@item @code{@emph{x} #rem @emph{y}} -@item @var{x} #/ @var{y} -@itemx @var{x} #mod @var{y} -@itemx @var{x} #* @var{y} -@itemx @var{x} #rem @var{y} A division or multiplication of fixed-point values which are treated as integers without any kind of scaling. -@item free @var{expr} @r{[}storage_pool = @var{xxx}@r{]} -Shows the storage pool associated with a @code{free} statement. +@item @code{free @emph{expr} [storage_pool = @emph{xxx}]} + +Shows the storage pool associated with a @cite{free} statement. + +@item @code{[subtype or type declaration]} -@item [subtype or type declaration] Used to list an equivalent declaration for an internally generated type that is referenced elsewhere in the listing. -@c @item freeze @var{type-name} @ovar{actions} -@c Expanding @ovar macro inline (explanation in macro def comments) -@item freeze @var{type-name} @r{[}@var{actions}@r{]} -Shows the point at which @var{type-name} is frozen, with possible +@item @code{freeze @emph{type-name} [@emph{actions}]} + +Shows the point at which @cite{type-name} is frozen, with possible associated actions to be performed at the freeze point. -@item reference @var{itype} -Reference (and hence definition) to internal type @var{itype}. +@item @code{reference @emph{itype}} + +Reference (and hence definition) to internal type @cite{itype}. + +@item @code{@emph{function-name}! (@emph{arg}, @emph{arg}, @emph{arg})} -@item @var{function-name}! (@var{arg}, @var{arg}, @var{arg}) Intrinsic function call. -@item @var{label-name} : label -Declaration of label @var{labelname}. +@item @code{@emph{label-name} : label} + +Declaration of label @cite{labelname}. + +@item @code{#$ @emph{subprogram-name}} -@item #$ @var{subprogram-name} An implicit call to a run-time support routine (to meet the requirement of H.3.1(9) in a convenient manner). -@item @var{expr} && @var{expr} && @var{expr} @dots{} && @var{expr} -A multiple concatenation (same effect as @var{expr} & @var{expr} & -@var{expr}, but handled more efficiently). +@item @code{@emph{expr} && @emph{expr} && @emph{expr} ... && @emph{expr}} + +A multiple concatenation (same effect as @cite{expr} & @cite{expr} & +@cite{expr}, but handled more efficiently). + +@item @code{[constraint_error]} + +Raise the @cite{Constraint_Error} exception. -@item [constraint_error] -Raise the @code{Constraint_Error} exception. +@item @code{@emph{expression}'reference} -@item @var{expression}'reference -A pointer to the result of evaluating @var{expression}. +A pointer to the result of evaluating @{expression@}. -@item @var{target-type}!(@var{source-expression}) -An unchecked conversion of @var{source-expression} to @var{target-type}. +@item @code{@emph{target-type}!(@emph{source-expression})} + +An unchecked conversion of @cite{source-expression} to @cite{target-type}. + +@item @code{[@emph{numerator}/@emph{denominator}]} -@item [@var{numerator}/@var{denominator}] Used to represent internal real literals (that) have no exact representation in base 2-16 (for example, the result of compile time evaluation of the expression 1.0/27.0). @end table +@end table + +@geindex -gnatD (gcc) + + +@table @asis + +@item @code{-gnatD[=nn]} -@item -gnatD[=nn] -@cindex @option{-gnatD} (@command{gcc}) -When used in conjunction with @option{-gnatG}, this switch causes +When used in conjunction with @emph{-gnatG}, this switch causes the expanded source, as described above for -@option{-gnatG} to be written to files with names -@file{xxx.dg}, where @file{xxx} is the normal file name, +@emph{-gnatG} to be written to files with names +@code{xxx.dg}, where @code{xxx} is the normal file name, instead of to the standard output file. For -example, if the source file name is @file{hello.adb}, then a file -@file{hello.adb.dg} will be written. The debugging -information generated by the @command{gcc} @option{-g} switch -will refer to the generated @file{xxx.dg} file. This allows +example, if the source file name is @code{hello.adb}, then a file +@code{hello.adb.dg} will be written. The debugging +information generated by the @emph{gcc} @emph{-g} switch +will refer to the generated @code{xxx.dg} file. This allows you to do source level debugging using the generated code which is sometimes useful for complex code, for example to find out exactly which part of a complex construction raised an exception. This switch also suppress generation of cross-reference information (see -@option{-gnatx}) since otherwise the cross-reference information -would refer to the @file{.dg} file, which would cause +@emph{-gnatx}) since otherwise the cross-reference information +would refer to the @code{.dg} file, which would cause confusion since this is not the original source file. -Note that @option{-gnatD} actually implies @option{-gnatG} +Note that @emph{-gnatD} actually implies @emph{-gnatG} automatically, so it is not necessary to give both options. -In other words @option{-gnatD} is equivalent to @option{-gnatDG}). +In other words @emph{-gnatD} is equivalent to @emph{-gnatDG}). -If the switch @option{-gnatL} is used in conjunction with -@cindex @option{-gnatL} (@command{gcc}) -@option{-gnatDG}, then the original source lines are interspersed +@geindex -gnatL (gcc) + +If the switch @emph{-gnatL} is used in conjunction with +@emph{-gnatDG}, then the original source lines are interspersed in the expanded source (as comment lines with the original line number). -The optional parameter @code{nn} if present after -gnatD specifies an +The optional parameter @cite{nn} if present after -gnatD specifies an alternative maximum line length that overrides the normal default of 72. This value is in the range 40-999999, values less than 40 being silently reset to 40. The equal sign is optional. +@end table + +@geindex -gnatr (gcc) + +@geindex pragma Restrictions + + +@table @asis + +@item @code{-gnatr} -@item -gnatr -@cindex @option{-gnatr} (@command{gcc}) -@cindex pragma Restrictions This switch causes pragma Restrictions to be treated as Restriction_Warnings so that violation of restrictions causes warnings rather than illegalities. This is useful during the development process when new restrictions are added or investigated. The switch also causes pragma Profile to be treated as Profile_Warnings, and pragma Restricted_Run_Time and pragma Ravenscar set restriction warnings rather than restrictions. +@end table + +@geindex -gnatR (gcc) + + +@table @asis + +@item @code{-gnatR[0|1|2|3[s]]} -@item -gnatR@r{[}0@r{|}1@r{|}2@r{|}3@r{[}s@r{]]} -@cindex @option{-gnatR} (@command{gcc}) This switch controls output from the compiler of a listing showing representation information for declared types and objects. For -@option{-gnatR0}, no information is output (equivalent to omitting -the @option{-gnatR} switch). For @option{-gnatR1} (which is the default, -so @option{-gnatR} with no parameter has the same effect), size and alignment +@emph{-gnatR0}, no information is output (equivalent to omitting +the @emph{-gnatR} switch). For @emph{-gnatR1} (which is the default, +so @emph{-gnatR} with no parameter has the same effect), size and alignment information is listed for declared array and record types. For -@option{-gnatR2}, size and alignment information is listed for all -declared types and objects. The @code{Linker_Section} is also listed for any -entity for which the @code{Linker_Section} is set explicitly or implicitly (the -latter case occurs for objects of a type for which a @code{Linker_Section} +@emph{-gnatR2}, size and alignment information is listed for all +declared types and objects. The @cite{Linker_Section} is also listed for any +entity for which the @cite{Linker_Section} is set explicitly or implicitly (the +latter case occurs for objects of a type for which a @cite{Linker_Section} is set). -Finally @option{-gnatR3} includes symbolic +Finally @emph{-gnatR3} includes symbolic expressions for values that are computed at run time for variant records. These symbolic expressions have a mostly obvious format with #n being used to represent the value of the n'th -discriminant. See source files @file{repinfo.ads/adb} in the -@code{GNAT} sources for full details on the format of @option{-gnatR3} -output. If the switch is followed by an s (e.g.@: @option{-gnatR2s}), then -the output is to a file with the name @file{file.rep} where +discriminant. See source files @code{repinfo.ads/adb} in the +@cite{GNAT} sources for full details on the format of @emph{-gnatR3} +output. If the switch is followed by an s (e.g., @emph{-gnatR2s}), then +the output is to a file with the name @code{file.rep} where file is the name of the corresponding source file. -@item -gnatRm[s] +@item @code{-gnatRm[s]} + This form of the switch controls output of subprogram conventions and parameter passing mechanisms for all subprograms. A following -@code{s} means output to a file as described above. +@cite{s} means output to a file as described above. Note that it is possible for record components to have zero size. In this case, the component clause uses an obvious extension of permitted -Ada syntax, for example @code{at 0 range 0 .. -1}. +Ada syntax, for example @cite{at 0 range 0 .. -1}. Representation information requires that code be generated (since it is the code generator that lays out complex data structures). If an attempt is made to output representation information when no code is generated, for example when a subunit is compiled on its own, then no information can be generated and the compiler outputs a message to this effect. +@end table + +@geindex -gnatS (gcc) -@item -gnatS -@cindex @option{-gnatS} (@command{gcc}) -The use of the switch @option{-gnatS} for an + +@table @asis + +@item @code{-gnatS} + +The use of the switch @emph{-gnatS} for an Ada compilation will cause the compiler to output a representation of package Standard in a form very close to standard Ada. It is not quite possible to @@ -7351,29 +14672,36 @@ Ada), but the output is easily readable to any Ada programmer, and is useful to determine the characteristics of target dependent types in package Standard. +@end table + +@geindex -gnatx (gcc) + + +@table @asis + +@item @code{-gnatx} -@item -gnatx -@cindex @option{-gnatx} (@command{gcc}) Normally the compiler generates full cross-referencing information in -the @file{ALI} file. This information is used by a number of tools, -including @code{gnatfind} and @code{gnatxref}. The @option{-gnatx} switch +the @code{ALI} file. This information is used by a number of tools, +including @cite{gnatfind} and @cite{gnatxref}. The @emph{-gnatx} switch suppresses this information. This saves some space and may slightly speed up compilation, but means that these tools cannot be used. @end table -@node Exception Handling Control +@node Exception Handling Control,Units to Sources Mapping Files,Debugging Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat id28}@anchor{119}@anchor{gnat_ugn/building_executable_programs_with_gnat exception-handling-control}@anchor{11a} @subsection Exception Handling Control -@noindent + GNAT uses two methods for handling exceptions at run-time. The -@code{setjmp/longjmp} method saves the context when entering +@cite{setjmp/longjmp} method saves the context when entering a frame with an exception handler. Then when an exception is raised, the context can be restored immediately, without the need for tracing stack frames. This method provides very fast exception propagation, but introduces significant overhead for the use of exception handlers, even if no exception is raised. -The other approach is called ``zero cost'' exception handling. +The other approach is called 'zero cost' exception handling. With this method, the compiler builds static tables to describe the exception ranges. No dynamic code is required when entering a frame containing an exception handler. When an exception is @@ -7384,17 +14712,19 @@ the propagation of exceptions, but there is no overhead for exception handlers if no exception is raised. Note that in this mode and in the context of mixed Ada and C/C++ programming, to propagate an exception through a C/C++ code, the C/C++ code -must be compiled with the @option{-funwind-tables} GCC's +must be compiled with the @emph{-funwind-tables} GCC's option. The following switches may be used to control which of the two exception handling methods is used. -@table @option -@c !sort! +@geindex --RTS=sjlj (gnatmake) + + +@table @asis + +@item @code{--RTS=sjlj} -@item --RTS=sjlj -@cindex @option{--RTS=sjlj} (@command{gnatmake}) This switch causes the setjmp/longjmp run-time (when available) to be used for exception handling. If the default mechanism for the target is zero cost exceptions, then @@ -7404,10 +14734,17 @@ This option is rarely used. One case in which it may be advantageous is if you have an application where exception raising is common and the overall performance of the application is improved by favoring exception propagation. +@end table + +@geindex --RTS=zcx (gnatmake) + +@geindex Zero Cost Exceptions + + +@table @asis + +@item @code{--RTS=zcx} -@item --RTS=zcx -@cindex @option{--RTS=zcx} (@command{gnatmake}) -@cindex Zero Cost Exceptions This switch causes the zero cost approach to be used for exception handling. If this is the default mechanism for the target (see below), then this switch is unneeded. If the default @@ -7418,19 +14755,23 @@ This option can only be used if the zero cost approach is available for the target in use, otherwise it will generate an error. @end table -@noindent -The same option @option{--RTS} must be used both for @command{gcc} -and @command{gnatbind}. Passing this option to @command{gnatmake} -(@pxref{Switches for gnatmake}) will ensure the required consistency +The same option @emph{--RTS} must be used both for @emph{gcc} +and @emph{gnatbind}. Passing this option to @emph{gnatmake} +(@ref{df,,Switches for gnatmake}) will ensure the required consistency through the compilation and binding steps. -@node Units to Sources Mapping Files +@node Units to Sources Mapping Files,Code Generation Control,Exception Handling Control,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat id29}@anchor{11b}@anchor{gnat_ugn/building_executable_programs_with_gnat units-to-sources-mapping-files}@anchor{fc} @subsection Units to Sources Mapping Files -@table @option -@item -gnatem=@var{path} -@cindex @option{-gnatem} (@command{gcc}) +@geindex -gnatem (gcc) + + +@table @asis + +@item @code{-gnatem=@emph{path}} + A mapping file is a way to communicate to the compiler two mappings: from unit names to file names (without any directory information) and from file names to path names (with full directory information). These mappings @@ -7440,583 +14781,329 @@ The use of mapping files is not required for correct operation of the compiler, but mapping files can improve efficiency, particularly when sources are read over a slow network connection. In normal operation, you need not be concerned with the format or use of mapping files, -and the @option{-gnatem} switch is not a switch that you would use +and the @emph{-gnatem} switch is not a switch that you would use explicitly. It is intended primarily for use by automatic tools such as -@command{gnatmake} running under the project file facility. The +@emph{gnatmake} running under the project file facility. The description here of the format of mapping files is provided for completeness and for possible use by other tools. A mapping file is a sequence of sets of three lines. In each set, the -first line is the unit name, in lower case, with @code{%s} appended -for specs and @code{%b} appended for bodies; the second line is the +first line is the unit name, in lower case, with @cite{%s} appended +for specs and @cite{%b} appended for bodies; the second line is the file name; and the third line is the path name. Example: -@smallexample - main%b - main.2.ada - /gnat/project1/sources/main.2.ada -@end smallexample -When the switch @option{-gnatem} is specified, the compiler will +@example +main%b +main.2.ada +/gnat/project1/sources/main.2.ada +@end example + +When the switch @emph{-gnatem} is specified, the compiler will create in memory the two mappings from the specified file. If there is any problem (nonexistent file, truncated file or duplicate entries), no mapping will be created. -Several @option{-gnatem} switches may be specified; however, only the +Several @emph{-gnatem} switches may be specified; however, only the last one on the command line will be taken into account. -When using a project file, @command{gnatmake} creates a temporary +When using a project file, @emph{gnatmake} creates a temporary mapping file and communicates it to the compiler using this switch. - @end table -@node Integrated Preprocessing -@subsection Integrated Preprocessing - -@noindent -GNAT sources may be preprocessed immediately before compilation. -In this case, the actual -text of the source is not the text of the source file, but is derived from it -through a process called preprocessing. Integrated preprocessing is specified -through switches @option{-gnatep} and/or @option{-gnateD}. @option{-gnatep} -indicates, through a text file, the preprocessing data to be used. -@option{-gnateD} specifies or modifies the values of preprocessing symbol. -Note that integrated preprocessing applies only to Ada source files, it is -not available for configuration pragma files. - -@noindent -Note that when integrated preprocessing is used, the output from the -preprocessor is not written to any external file. Instead it is passed -internally to the compiler. If you need to preserve the result of -preprocessing in a file, then you should use @command{gnatprep} -to perform the desired preprocessing in stand-alone mode. - -@noindent -It is recommended that @command{gnatmake} switch -s should be -used when Integrated Preprocessing is used. The reason is that preprocessing -with another Preprocessing Data file without changing the sources will -not trigger recompilation without this switch. - -@noindent -Note that @command{gnatmake} switch -m will almost -always trigger recompilation for sources that are preprocessed, -because @command{gnatmake} cannot compute the checksum of the source after -preprocessing. - -@noindent -The actual preprocessing function is described in details in section -@ref{Preprocessing with gnatprep}. This section only describes how integrated -preprocessing is triggered and parameterized. - -@table @code - -@item -gnatep=@var{file} -@cindex @option{-gnatep} (@command{gcc}) -This switch indicates to the compiler the file name (without directory -information) of the preprocessor data file to use. The preprocessor data file -should be found in the source directories. Note that when the compiler is -called by a builder such as (@command{gnatmake} with a project -file, if the object directory is not also a source directory, the builder needs -to be called with @option{-x}. - -@noindent -A preprocessing data file is a text file with significant lines indicating -how should be preprocessed either a specific source or all sources not -mentioned in other lines. A significant line is a nonempty, non-comment line. -Comments are similar to Ada comments. - -@noindent -Each significant line starts with either a literal string or the character '*'. -A literal string is the file name (without directory information) of the source -to preprocess. A character '*' indicates the preprocessing for all the sources -that are not specified explicitly on other lines (order of the lines is not -significant). It is an error to have two lines with the same file name or two -lines starting with the character '*'. - -@noindent -After the file name or the character '*', another optional literal string -indicating the file name of the definition file to be used for preprocessing -(@pxref{Form of Definitions File}). The definition files are found by the -compiler in one of the source directories. In some cases, when compiling -a source in a directory other than the current directory, if the definition -file is in the current directory, it may be necessary to add the current -directory as a source directory through switch -I., otherwise -the compiler would not find the definition file. - -@noindent -Then, optionally, switches similar to those of @code{gnatprep} may -be found. Those switches are: - -@table @code - -@item -b -Causes both preprocessor lines and the lines deleted by -preprocessing to be replaced by blank lines, preserving the line number. -This switch is always implied; however, if specified after @option{-c} -it cancels the effect of @option{-c}. - -@item -c -Causes both preprocessor lines and the lines deleted -by preprocessing to be retained as comments marked -with the special string ``@code{--! }''. - -@item -Dsymbol=value -Define or redefine a symbol, associated with value. A symbol is an Ada -identifier, or an Ada reserved word, with the exception of @code{if}, -@code{else}, @code{elsif}, @code{end}, @code{and}, @code{or} and @code{then}. -@code{value} is either a literal string, an Ada identifier or any Ada reserved -word. A symbol declared with this switch replaces a symbol with the -same name defined in a definition file. - -@item -s -Causes a sorted list of symbol names and values to be -listed on the standard output file. - -@item -u -Causes undefined symbols to be treated as having the value @code{FALSE} -in the context -of a preprocessor test. In the absence of this option, an undefined symbol in -a @code{#if} or @code{#elsif} test will be treated as an error. - -@end table - -@noindent -Examples of valid lines in a preprocessor data file: - -@smallexample - "toto.adb" "prep.def" -u - -- preprocess "toto.adb", using definition file "prep.def", - -- undefined symbol are False. - - * -c -DVERSION=V101 - -- preprocess all other sources without a definition file; - -- suppressed lined are commented; symbol VERSION has the value V101. - - "titi.adb" "prep2.def" -s - -- preprocess "titi.adb", using definition file "prep2.def"; - -- list all symbols with their values. -@end smallexample - -@item -gnateDsymbol@r{[}=value@r{]} -@cindex @option{-gnateD} (@command{gcc}) -Define or redefine a preprocessing symbol, associated with value. If no value -is given on the command line, then the value of the symbol is @code{True}. -A symbol is an identifier, following normal Ada (case-insensitive) -rules for its syntax, and value is either an arbitrary string between double -quotes or any sequence (including an empty sequence) of characters from the -set (letters, digits, period, underline). -Ada reserved words may be used as symbols, with the exceptions of @code{if}, -@code{else}, @code{elsif}, @code{end}, @code{and}, @code{or} and @code{then}. - -@noindent -Examples: - -@smallexample - -gnateDToto=Titi - -gnateDFoo - -gnateDFoo=\"Foo-Bar\" -@end smallexample - -@noindent -A symbol declared with this switch on the command line replaces a -symbol with the same name either in a definition file or specified with a -switch -D in the preprocessor data file. - -@noindent -This switch is similar to switch @option{-D} of @code{gnatprep}. - -@item -gnateG -When integrated preprocessing is performed and the preprocessor modifies -the source text, write the result of this preprocessing into a file -<source>.prep. - -@end table - -@node Code Generation Control +@node Code Generation Control,,Units to Sources Mapping Files,Compiler Switches +@anchor{gnat_ugn/building_executable_programs_with_gnat code-generation-control}@anchor{11c}@anchor{gnat_ugn/building_executable_programs_with_gnat id30}@anchor{11d} @subsection Code Generation Control -@noindent The GCC technology provides a wide range of target dependent -@option{-m} switches for controlling +@code{-m} switches for controlling details of code generation with respect to different versions of -architectures. This includes variations in instruction sets (e.g.@: +architectures. This includes variations in instruction sets (e.g., different members of the power pc family), and different requirements -for optimal arrangement of instructions (e.g.@: different members of -the x86 family). The list of available @option{-m} switches may be +for optimal arrangement of instructions (e.g., different members of +the x86 family). The list of available @emph{-m} switches may be found in the GCC documentation. -Use of these @option{-m} switches may in some cases result in improved +Use of these @emph{-m} switches may in some cases result in improved code performance. -The @value{EDITION} technology is tested and qualified without any -@option{-m} switches, +The GNAT technology is tested and qualified without any +@code{-m} switches, so generally the most reliable approach is to avoid the use of these switches. However, we generally expect most of these switches to work -successfully with @value{EDITION}, and many customers have reported successful +successfully with GNAT, and many customers have reported successful use of these options. -Our general advice is to avoid the use of @option{-m} switches unless +Our general advice is to avoid the use of @emph{-m} switches unless special needs lead to requirements in this area. In particular, -there is no point in using @option{-m} switches to improve performance +there is no point in using @emph{-m} switches to improve performance unless you actually see a performance improvement. +@node Binding with gnatbind,Linking with gnatlink,Compiler Switches,Building Executable Programs with GNAT +@anchor{gnat_ugn/building_executable_programs_with_gnat binding-with-gnatbind}@anchor{1f}@anchor{gnat_ugn/building_executable_programs_with_gnat id31}@anchor{11e} +@section Binding with @cite{gnatbind} -@node Search Paths and the Run-Time Library (RTL) -@section Search Paths and the Run-Time Library (RTL) - -@noindent -With the GNAT source-based library system, the compiler must be able to -find source files for units that are needed by the unit being compiled. -Search paths are used to guide this process. - -The compiler compiles one source file whose name must be given -explicitly on the command line. In other words, no searching is done -for this file. To find all other source files that are needed (the most -common being the specs of units), the compiler examines the following -directories, in the following order: - -@enumerate -@item -The directory containing the source file of the main unit being compiled -(the file name on the command line). - -@item -Each directory named by an @option{-I} switch given on the -@command{gcc} command line, in the order given. - -@item -@findex ADA_PRJ_INCLUDE_FILE -Each of the directories listed in the text file whose name is given -by the @env{ADA_PRJ_INCLUDE_FILE} environment variable. - -@noindent -@env{ADA_PRJ_INCLUDE_FILE} is normally set by gnatmake or by the gnat -driver when project files are used. It should not normally be set -by other means. - -@item -@findex ADA_INCLUDE_PATH -Each of the directories listed in the value of the -@env{ADA_INCLUDE_PATH} environment variable. -Construct this value -exactly as the @env{PATH} environment variable: a list of directory -names separated by colons (semicolons when working with the NT version). - -@item -The content of the @file{ada_source_path} file which is part of the GNAT -installation tree and is used to store standard libraries such as the -GNAT Run Time Library (RTL) source files. -@ref{Installing a library} -@end enumerate - -@noindent -Specifying the switch @option{-I-} -inhibits the use of the directory -containing the source file named in the command line. You can still -have this directory on your search path, but in this case it must be -explicitly requested with a @option{-I} switch. - -Specifying the switch @option{-nostdinc} -inhibits the search of the default location for the GNAT Run Time -Library (RTL) source files. - -The compiler outputs its object files and ALI files in the current -working directory. -Caution: The object file can be redirected with the @option{-o} switch; -however, @command{gcc} and @code{gnat1} have not been coordinated on this -so the @file{ALI} file will not go to the right place. Therefore, you should -avoid using the @option{-o} switch. - -@findex System.IO -The packages @code{Ada}, @code{System}, and @code{Interfaces} and their -children make up the GNAT RTL, together with the simple @code{System.IO} -package used in the @code{"Hello World"} example. The sources for these units -are needed by the compiler and are kept together in one directory. Not -all of the bodies are needed, but all of the sources are kept together -anyway. In a normal installation, you need not specify these directory -names when compiling or binding. Either the environment variables or -the built-in defaults cause these files to be found. - -In addition to the language-defined hierarchies (@code{System}, @code{Ada} and -@code{Interfaces}), the GNAT distribution provides a fourth hierarchy, -consisting of child units of @code{GNAT}. This is a collection of generally -useful types, subprograms, etc. @xref{Top, GNAT Reference Manual, About -This Guid, gnat_rm, GNAT Reference Manual}, for further details. - -Besides simplifying access to the RTL, a major use of search paths is -in compiling sources from multiple directories. This can make -development environments much more flexible. - -@node Order of Compilation Issues -@section Order of Compilation Issues - -@noindent -If, in our earlier example, there was a spec for the @code{hello} -procedure, it would be contained in the file @file{hello.ads}; yet this -file would not have to be explicitly compiled. This is the result of the -model we chose to implement library management. Some of the consequences -of this model are as follows: - -@itemize @bullet -@item -There is no point in compiling specs (except for package -specs with no bodies) because these are compiled as needed by clients. If -you attempt a useless compilation, you will receive an error message. -It is also useless to compile subunits because they are compiled as needed -by the parent. - -@item -There are no order of compilation requirements: performing a -compilation never obsoletes anything. The only way you can obsolete -something and require recompilations is to modify one of the -source files on which it depends. - -@item -There is no library as such, apart from the ALI files -(@pxref{The Ada Library Information Files}, for information on the format -of these files). For now we find it convenient to create separate ALI files, -but eventually the information therein may be incorporated into the object -file directly. - -@item -When you compile a unit, the source files for the specs of all units -that it @code{with}'s, all its subunits, and the bodies of any generics it -instantiates must be available (reachable by the search-paths mechanism -described above), or you will receive a fatal error message. -@end itemize - -@node Examples -@section Examples -@noindent -The following are some typical Ada compilation command line examples: - -@table @code -@item $ gcc -c xyz.adb -Compile body in file @file{xyz.adb} with all default options. - -@item $ gcc -c -O2 -gnata xyz-def.adb - -Compile the child unit package in file @file{xyz-def.adb} with extensive -optimizations, and pragma @code{Assert}/@code{Debug} statements -enabled. - -@item $ gcc -c -gnatc abc-def.adb -Compile the subunit in file @file{abc-def.adb} in semantic-checking-only -mode. -@end table +@geindex gnatbind -@node Binding with gnatbind -@chapter Binding with @code{gnatbind} -@findex gnatbind +This chapter describes the GNAT binder, @cite{gnatbind}, which is used +to bind compiled GNAT objects. -@menu -* Running gnatbind:: -* Switches for gnatbind:: -* Command-Line Access:: -* Search Paths for gnatbind:: -* Examples of gnatbind Usage:: -@end menu +Note: to invoke @cite{gnatbind} with a project file, use the @cite{gnat} +driver (see @ref{11f,,The GNAT Driver and Project Files}). -@noindent -This chapter describes the GNAT binder, @code{gnatbind}, which is used -to bind compiled GNAT objects. +The @cite{gnatbind} program performs four separate functions: -Note: to invoke @code{gnatbind} with a project file, use the @code{gnat} -driver (see @ref{The GNAT Driver and Project Files}). -The @code{gnatbind} program performs four separate functions: +@itemize * -@enumerate -@item +@item Checks that a program is consistent, in accordance with the rules in Chapter 10 of the Ada Reference Manual. In particular, error messages are generated if a program uses inconsistent versions of a given unit. -@item +@item Checks that an acceptable order of elaboration exists for the program and issues an error message if it cannot find an order of elaboration that satisfies the rules in Chapter 10 of the Ada Language Manual. -@item +@item Generates a main program incorporating the given elaboration order. This program is a small Ada package (body and spec) that must be subsequently compiled using the GNAT compiler. The necessary compilation step is usually -performed automatically by @command{gnatlink}. The two most important +performed automatically by @emph{gnatlink}. The two most important functions of this program are to call the elaboration routines of units in an appropriate order and to call the main program. -@item +@item Determines the set of object files required by the given main program. This information is output in the forms of comments in the generated program, -to be read by the @command{gnatlink} utility used to link the Ada application. -@end enumerate +to be read by the @emph{gnatlink} utility used to link the Ada application. +@end itemize + +@menu +* Running gnatbind:: +* Switches for gnatbind:: +* Command-Line Access:: +* Search Paths for gnatbind:: +* Examples of gnatbind Usage:: -@node Running gnatbind -@section Running @code{gnatbind} +@end menu + +@node Running gnatbind,Switches for gnatbind,,Binding with gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat running-gnatbind}@anchor{120}@anchor{gnat_ugn/building_executable_programs_with_gnat id32}@anchor{121} +@subsection Running @cite{gnatbind} -@noindent -The form of the @code{gnatbind} command is -@smallexample -@c $ gnatbind @ovar{switches} @var{mainprog}@r{[}.ali@r{]} @ovar{switches} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatbind @r{[}@var{switches}@r{]} @var{mainprog}@r{[}.ali@r{]} @r{[}@var{switches}@r{]} -@end smallexample +The form of the @cite{gnatbind} command is -@noindent -where @file{@var{mainprog}.adb} is the Ada file containing the main program -unit body. @code{gnatbind} constructs an Ada +@example +$ gnatbind [`switches`] `mainprog`[.ali] [`switches`] +@end example + +where @code{mainprog.adb} is the Ada file containing the main program +unit body. @cite{gnatbind} constructs an Ada package in two files whose names are -@file{b~@var{mainprog}.ads}, and @file{b~@var{mainprog}.adb}. +@code{b~mainprog.ads}, and @code{b~mainprog.adb}. For example, if given the -parameter @file{hello.ali}, for a main program contained in file -@file{hello.adb}, the binder output files would be @file{b~hello.ads} -and @file{b~hello.adb}. +parameter @code{hello.ali}, for a main program contained in file +@code{hello.adb}, the binder output files would be @code{b~hello.ads} +and @code{b~hello.adb}. When doing consistency checking, the binder takes into consideration any source files it can locate. For example, if the binder determines -that the given main program requires the package @code{Pack}, whose -@file{.ALI} -file is @file{pack.ali} and whose corresponding source spec file is -@file{pack.ads}, it attempts to locate the source file @file{pack.ads} +that the given main program requires the package @cite{Pack}, whose +@code{.ALI} +file is @code{pack.ali} and whose corresponding source spec file is +@code{pack.ads}, it attempts to locate the source file @code{pack.ads} (using the same search path conventions as previously described for the -@command{gcc} command). If it can locate this source file, it checks that +@emph{gcc} command). If it can locate this source file, it checks that the time stamps -or source checksums of the source and its references to in @file{ALI} files -match. In other words, any @file{ALI} files that mentions this spec must have +or source checksums of the source and its references to in @code{ALI} files +match. In other words, any @code{ALI} files that mentions this spec must have resulted from compiling this version of the source file (or in the case where the source checksums match, a version close enough that the difference does not matter). -@cindex Source files, use by binder +@geindex Source files +@geindex use by binder + The effect of this consistency checking, which includes source files, is that the binder ensures that the program is consistent with the latest version of the source files that can be located at bind time. Editing a source file without compiling files that depend on the source file cause error messages to be generated by the binder. -For example, suppose you have a main program @file{hello.adb} and a -package @code{P}, from file @file{p.ads} and you perform the following +For example, suppose you have a main program @code{hello.adb} and a +package @cite{P}, from file @code{p.ads} and you perform the following steps: -@enumerate -@item -Enter @code{gcc -c hello.adb} to compile the main program. -@item -Enter @code{gcc -c p.ads} to compile package @code{P}. +@itemize * -@item -Edit file @file{p.ads}. +@item +Enter @cite{gcc -c hello.adb} to compile the main program. -@item -Enter @code{gnatbind hello}. -@end enumerate +@item +Enter @cite{gcc -c p.ads} to compile package @cite{P}. + +@item +Edit file @code{p.ads}. + +@item +Enter @cite{gnatbind hello}. +@end itemize -@noindent -At this point, the file @file{p.ali} contains an out-of-date time stamp -because the file @file{p.ads} has been edited. The attempt at binding +At this point, the file @code{p.ali} contains an out-of-date time stamp +because the file @code{p.ads} has been edited. The attempt at binding fails, and the binder generates the following error messages: -@smallexample +@example error: "hello.adb" must be recompiled ("p.ads" has been modified) error: "p.ads" has been modified and must be recompiled -@end smallexample +@end example -@noindent Now both files must be recompiled as indicated, and then the bind can succeed, generating a main program. You need not normally be concerned with the contents of this file, but for reference purposes a sample -binder output file is given in @ref{Example of Binder Output File}. +binder output file is given in @ref{10,,Example of Binder Output File}. -In most normal usage, the default mode of @command{gnatbind} which is to +In most normal usage, the default mode of @emph{gnatbind} which is to generate the main package in Ada, as described in the previous section. In particular, this means that any Ada programmer can read and understand the generated main program. It can also be debugged just like any other -Ada code provided the @option{-g} switch is used for -@command{gnatbind} and @command{gnatlink}. +Ada code provided the @emph{-g} switch is used for +@emph{gnatbind} and @emph{gnatlink}. -@node Switches for gnatbind -@section Switches for @command{gnatbind} +@node Switches for gnatbind,Command-Line Access,Running gnatbind,Binding with gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat id33}@anchor{122}@anchor{gnat_ugn/building_executable_programs_with_gnat switches-for-gnatbind}@anchor{123} +@subsection Switches for @emph{gnatbind} -@noindent -The following switches are available with @code{gnatbind}; details will + +The following switches are available with @cite{gnatbind}; details will be presented in subsequent sections. -@menu -* Consistency-Checking Modes:: -* Binder Error Message Control:: -* Elaboration Control:: -* Output Control:: -* Dynamic Allocation Control:: -* Binding with Non-Ada Main Programs:: -* Binding Programs with No Main Subprogram:: -@end menu +@geindex --version (gnatbind) + -@table @option -@c !sort! +@table @asis + +@item @code{--version} -@item --version -@cindex @option{--version} @command{gnatbind} Display Copyright and version, then exit disregarding all other options. +@end table + +@geindex --help (gnatbind) -@item --help -@cindex @option{--help} @command{gnatbind} -If @option{--version} was not used, display usage, then exit disregarding + +@table @asis + +@item @code{--help} + +If @emph{--version} was not used, display usage, then exit disregarding all other options. +@end table + +@geindex -a (gnatbind) + + +@table @asis + +@item @code{-a} -@item -a -@cindex @option{-a} @command{gnatbind} Indicates that, if supported by the platform, the adainit procedure should be treated as an initialisation routine by the linker (a constructor). This is intended to be used by the Project Manager to automatically initialize shared Stand-Alone Libraries. +@end table + +@geindex -aO (gnatbind) + + +@table @asis + +@item @code{-aO} -@item -aO -@cindex @option{-aO} (@command{gnatbind}) Specify directory to be searched for ALI files. +@end table + +@geindex -aI (gnatbind) + + +@table @asis + +@item @code{-aI} -@item -aI -@cindex @option{-aI} (@command{gnatbind}) Specify directory to be searched for source file. +@end table + +@geindex -A (gnatbind) + + +@table @asis + +@item @code{-A[=@emph{filename}]} -@item -A@r{[=}@var{filename}@r{]} -@cindex @option{-A} (@command{gnatbind}) Output ALI list (to standard output or to the named file). +@end table + +@geindex -b (gnatbind) + + +@table @asis -@item -b -@cindex @option{-b} (@command{gnatbind}) -Generate brief messages to @file{stderr} even if verbose mode set. +@item @code{-b} + +Generate brief messages to @code{stderr} even if verbose mode set. +@end table + +@geindex -c (gnatbind) + + +@table @asis + +@item @code{-c} -@item -c -@cindex @option{-c} (@command{gnatbind}) Check only, no generation of binder output file. +@end table + +@geindex -dnn[k|m] (gnatbind) + + +@table @asis + +@item @code{-d@emph{nn}[k|m]} -@item -d@var{nn}@r{[}k@r{|}m@r{]} -@cindex @option{-d@var{nn}@r{[}k@r{|}m@r{]}} (@command{gnatbind}) This switch can be used to change the default task stack size value -to a specified size @var{nn}, which is expressed in bytes by default, or -in kilobytes when suffixed with @var{k} or in megabytes when suffixed -with @var{m}. -In the absence of a @samp{@r{[}k@r{|}m@r{]}} suffix, this switch is equivalent, +to a specified size @cite{nn}, which is expressed in bytes by default, or +in kilobytes when suffixed with @cite{k} or in megabytes when suffixed +with @cite{m}. +In the absence of a @code{[k|m]} suffix, this switch is equivalent, in effect, to completing all task specs with -@smallexample @c ada - @b{pragma} Storage_Size (nn); -@end smallexample + +@example +pragma Storage_Size (nn); +@end example + When they do not already have such a pragma. +@end table + +@geindex -D (gnatbind) + + +@table @asis + +@item @code{-D@emph{nn}[k|m]} -@item -D@var{nn}@r{[}k@r{|}m@r{]} -@cindex @option{-D} (@command{gnatbind}) This switch can be used to change the default secondary stack size value -to a specified size @var{nn}, which is expressed in bytes by default, or -in kilobytes when suffixed with @var{k} or in megabytes when suffixed -with @var{m}. +to a specified size @cite{nn}, which is expressed in bytes by default, or +in kilobytes when suffixed with @cite{k} or in megabytes when suffixed +with @cite{m}. The secondary stack is used to deal with functions that return a variable sized result, for example a function returning an unconstrained @@ -8032,80 +15119,114 @@ For certain targets, notably VxWorks 653, the secondary stack is allocated by carving off a fixed ratio chunk of the primary task stack. The -D option is used to define the size of the environment task's secondary stack. +@end table + +@geindex -e (gnatbind) + + +@table @asis + +@item @code{-e} -@item -e -@cindex @option{-e} (@command{gnatbind}) Output complete list of elaboration-order dependencies. +@end table + +@geindex -E (gnatbind) + + +@table @asis + +@item @code{-E} -@item -E -@cindex @option{-E} (@command{gnatbind}) Store tracebacks in exception occurrences when the target supports it. -@ignore -@c The following may get moved to an appendix -This option is currently supported on the following targets: -all x86 ports, Solaris, Windows, HP-UX, AIX, PowerPC VxWorks and Alpha VxWorks. -@end ignore -See also the packages @code{GNAT.Traceback} and -@code{GNAT.Traceback.Symbolic} for more information. -Note that on x86 ports, you must not use @option{-fomit-frame-pointer} -@command{gcc} option. - -@item -F -@cindex @option{-F} (@command{gnatbind}) -Force the checks of elaboration flags. @command{gnatbind} does not normally + +See also the packages @cite{GNAT.Traceback} and +@cite{GNAT.Traceback.Symbolic} for more information. +Note that on x86 ports, you must not use @emph{-fomit-frame-pointer} +@emph{gcc} option. +@end table + +@geindex -F (gnatbind) + + +@table @asis + +@item @code{-F} + +Force the checks of elaboration flags. @emph{gnatbind} does not normally generate checks of elaboration flags for the main executable, except when a Stand-Alone Library is used. However, there are cases when this cannot be detected by gnatbind. An example is importing an interface of a Stand-Alone Library through a pragma Import and only specifying through a linker switch this Stand-Alone Library. This switch is used to guarantee that elaboration flag checks are generated. +@end table + +@geindex -h (gnatbind) + + +@table @asis + +@item @code{-h} -@item -h -@cindex @option{-h} (@command{gnatbind}) Output usage (help) information -@item -H32 -@cindex @option{-H32} (@command{gnatbind}) -Use 32-bit allocations for @code{__gnat_malloc} (and thus for access types). -For further details see @ref{Dynamic Allocation Control}. +@geindex -H32 (gnatbind) + +@item @code{-H32} -@item -H64 -@cindex @option{-H64} (@command{gnatbind}) -Use 64-bit allocations for @code{__gnat_malloc} (and thus for access types). -@cindex @code{__gnat_malloc} -For further details see @ref{Dynamic Allocation Control}. +Use 32-bit allocations for @cite{__gnat_malloc} (and thus for access types). +For further details see @ref{124,,Dynamic Allocation Control}. + +@geindex -H64 (gnatbind) + +@geindex __gnat_malloc + +@item @code{-H64} + +Use 64-bit allocations for @cite{__gnat_malloc} (and thus for access types). +For further details see @ref{124,,Dynamic Allocation Control}. + +@geindex -I (gnatbind) + +@item @code{-I} -@item -I -@cindex @option{-I} (@command{gnatbind}) Specify directory to be searched for source and ALI files. -@item -I- -@cindex @option{-I-} (@command{gnatbind}) -Do not look for sources in the current directory where @code{gnatbind} was +@geindex -I- (gnatbind) + +@item @code{-I-} + +Do not look for sources in the current directory where @cite{gnatbind} was invoked, and do not look for ALI files in the directory containing the -ALI file named in the @code{gnatbind} command line. +ALI file named in the @cite{gnatbind} command line. + +@geindex -l (gnatbind) + +@item @code{-l} -@item -l -@cindex @option{-l} (@command{gnatbind}) Output chosen elaboration order. -@item -L@var{xxx} -@cindex @option{-L} (@command{gnatbind}) +@geindex -L (gnatbind) + +@item @code{-L@emph{xxx}} + Bind the units for library building. In this case the adainit and -adafinal procedures (@pxref{Binding with Non-Ada Main Programs}) -are renamed to @var{xxx}init and -@var{xxx}final. -Implies -n. -(@xref{GNAT and Libraries}, for more details.) - -@item -Mxyz -@cindex @option{-M} (@command{gnatbind}) +adafinal procedures (@ref{ba,,Binding with Non-Ada Main Programs}) +are renamed to @cite{xxx`init and `xxx`final. Implies -n. (:ref:`GNAT_and_Libraries}, for more details.) + +@geindex -M (gnatbind) + +@item @code{-M@emph{xyz}} + Rename generated main program from main to xyz. This option is supported on cross environments only. -@item -m@var{n} -@cindex @option{-m} (@command{gnatbind}) -Limit number of detected errors or warnings to @var{n}, where @var{n} is +@geindex -m (gnatbind) + +@item @code{-m@emph{n}} + +Limit number of detected errors or warnings to @cite{n}, where @cite{n} is in the range 1..999999. The default value if no switch is given is 9999. If the number of warnings reaches this limit, then a message is output and further warnings are suppressed, the bind @@ -8114,62 +15235,90 @@ limit, then a message is output and the bind is abandoned. A value of zero means that no limit is enforced. The equal sign is optional. -@item -n -@cindex @option{-n} (@command{gnatbind}) +@geindex -n (gnatbind) + +@item @code{-n} + No main program. -@item -nostdinc -@cindex @option{-nostdinc} (@command{gnatbind}) +@geindex -nostdinc (gnatbind) + +@item @code{-nostdinc} + Do not look for sources in the system default directory. -@item -nostdlib -@cindex @option{-nostdlib} (@command{gnatbind}) +@geindex -nostdlib (gnatbind) + +@item @code{-nostdlib} + Do not look for library files in the system default directory. -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@code{gnatbind}) +@geindex --RTS (gnatbind) + +@item @code{--RTS=@emph{rts-path}} + Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). +equivalent @emph{gnatmake} flag (@ref{df,,Switches for gnatmake}). + +@geindex -o (gnatbind) -@item -o @var{file} -@cindex @option{-o } (@command{gnatbind}) -Name the output file @var{file} (default is @file{b~@var{xxx}.adb}). +@item @code{-o @emph{file}} + +Name the output file @cite{file} (default is @code{b~`xxx}.adb`). Note that if this option is used, then linking must be done manually, gnatlink cannot be used. -@item -O@r{[=}@var{filename}@r{]} -@cindex @option{-O} (@command{gnatbind}) +@geindex -O (gnatbind) + +@item @code{-O[=@emph{filename}]} + Output object list (to standard output or to the named file). -@item -p -@cindex @option{-p} (@command{gnatbind}) +@geindex -p (gnatbind) + +@item @code{-p} + Pessimistic (worst-case) elaboration order -@item -P -@cindex @option{-P} (@command{gnatbind}) +@geindex -P (gnatbind) + +@item @code{-P} + Generate binder file suitable for CodePeer. -@item -R -@cindex @option{-R} (@command{gnatbind}) +@geindex -R (gnatbind) + +@item @code{-R} + Output closure source list, which includes all non-run-time units that are included in the bind. -@item -Ra -@cindex @option{-Ra} (@command{gnatbind}) -Like @option{-R} but the list includes run-time units. +@geindex -Ra (gnatbind) + +@item @code{-Ra} + +Like @emph{-R} but the list includes run-time units. + +@geindex -s (gnatbind) + +@item @code{-s} -@item -s -@cindex @option{-s} (@command{gnatbind}) Require all source files to be present. -@item -S@var{xxx} -@cindex @option{-S} (@command{gnatbind}) +@geindex -S (gnatbind) + +@item @code{-S@emph{xxx}} + Specifies the value to be used when detecting uninitialized scalar objects with pragma Initialize_Scalars. -The @var{xxx} string specified with the switch is one of: -@itemize @bullet +The @cite{xxx} string specified with the switch is one of: + + +@itemize * + +@item +@code{in} for an invalid value*. -@item ``@option{in}'' for an invalid value If zero is invalid for the discrete type in question, then the scalar value is set to all zero bits. For signed discrete types, the largest possible negative value of @@ -8178,7 +15327,9 @@ For unsigned discrete types, the underlying scalar value is set to all one bits. For floating-point types, a NaN value is set (see body of package System.Scalar_Values for exact values). -@item ``@option{lo}'' for low value +@item +@code{lo} for low value. + If zero is invalid for the discrete type in question, then the scalar value is set to all zero bits. For signed discrete types, the largest possible negative value of @@ -8187,7 +15338,9 @@ For unsigned discrete types, the underlying scalar value is set to all zero bits. For floating-point, a small value is set (see body of package System.Scalar_Values for exact values). -@item ``@option{hi}'' for high value +@item +@code{hi} for high value. + If zero is invalid for the discrete type in question, then the scalar value is set to all one bits. For signed discrete types, the largest possible positive value of @@ -8196,35 +15349,50 @@ For unsigned discrete types, the underlying scalar value is set to all one bits. For floating-point, a large value is set (see body of package System.Scalar_Values for exact values). -@item ``@option{@var{xx}}'' for hex value (two hex digits) +@item +@cite{xx} for hex value (two hex digits). + The underlying scalar is set to a value consisting of repeated bytes, whose -value corresponds to the given value. For example if @option{BF} is given, -then a 32-bit scalar value will be set to the bit patterm 16#BFBFBFBF#. +value corresponds to the given value. For example if @code{BF} is given, +then a 32-bit scalar value will be set to the bit patterm @code{16#BFBFBFBF#}. @end itemize -In addition, you can specify @option{-Sev} to indicate that the value is +@geindex GNAT_INIT_SCALARS + +In addition, you can specify @emph{-Sev} to indicate that the value is to be set at run time. In this case, the program will look for an environment -@cindex GNAT_INIT_SCALARS -variable of the form @env{GNAT_INIT_SCALARS=@var{xx}}, where @var{xx} is one -of @option{in/lo/hi/@var{xx}} with the same meanings as above. +variable of the form @code{GNAT_INIT_SCALARS=@emph{yy}}, where @cite{yy} is one +of @emph{in/lo/hi/`xx*` with the same meanings as above. If no environment variable is found, or if it does not have a valid value, -then the default is @option{in} (invalid values). +then the default is *in} (invalid values). +@end table + +@geindex -static (gnatbind) + + +@table @asis + +@item @code{-static} -@item -static -@cindex @option{-static} (@code{gnatbind}) Link against a static GNAT run time. -@item -shared -@cindex @option{-shared} (@code{gnatbind}) +@geindex -shared (gnatbind) + +@item @code{-shared} + Link against a shared GNAT run time when available. -@item -t -@cindex @option{-t} (@code{gnatbind}) +@geindex -t (gnatbind) + +@item @code{-t} + Tolerate time stamp and other consistency errors -@item -T@var{n} -@cindex @option{-T} (@code{gnatbind}) -Set the time slice value to @var{n} milliseconds. If the system supports +@geindex -T (gnatbind) + +@item @code{-T@emph{n}} + +Set the time slice value to @cite{n} milliseconds. If the system supports the specification of a specific time slice value, then the indicated value is used. If the system does not support specific time slice values, but does support some general notion of round-robin scheduling, then any @@ -8234,84 +15402,118 @@ A value of zero is treated specially. It turns off time slicing, and in addition, indicates to the tasking run time that the semantics should match as closely as possible the Annex D requirements of the Ada RM, and in particular sets the default -scheduling policy to @code{FIFO_Within_Priorities}. +scheduling policy to @cite{FIFO_Within_Priorities}. + +@geindex -u (gnatbind) -@item -u@var{n} -@cindex @option{-u} (@code{gnatbind}) -Enable dynamic stack usage, with @var{n} results stored and displayed +@item @code{-u@emph{n}} + +Enable dynamic stack usage, with @cite{n} results stored and displayed at program termination. A result is generated when a task terminates. Results that can't be stored are displayed on the fly, at task termination. This option is currently not supported on Itanium -platforms. (See @ref{Dynamic Stack Usage Analysis} for details.) +platforms. (See @ref{125,,Dynamic Stack Usage Analysis} for details.) + +@geindex -v (gnatbind) + +@item @code{-v} -@item -v -@cindex @option{-v} (@code{gnatbind}) Verbose mode. Write error messages, header, summary output to -@file{stdout}. +@code{stdout}. + +@geindex -w (gnatbind) -@item -w@var{x} -@cindex @option{-w} (@code{gnatbind}) -Warning mode (@var{x}=s/e for suppress/treat as error) +@item @code{-w@emph{x}} +Warning mode; @cite{x} = s/e for suppress/treat as error + +@geindex -Wx (gnatbind) + +@item @code{-Wx@emph{e}} -@item -Wx@var{e} -@cindex @option{-Wx} (@code{gnatbind}) Override default wide character encoding for standard Text_IO files. -@item -x -@cindex @option{-x} (@code{gnatbind}) +@geindex -x (gnatbind) + +@item @code{-x} + Exclude source files (check object consistency only). +@geindex -Xnnn (gnatbind) + +@item @code{-X@emph{nnn}} -@item -X@var{nnn} -@cindex @option{-X@var{nnn}} (@code{gnatbind}) Set default exit status value, normally 0 for POSIX compliance. +@geindex -y (gnatbind) + +@item @code{-y} + +Enable leap seconds support in @cite{Ada.Calendar} and its children. + +@geindex -z (gnatbind) -@item -y -@cindex @option{-y} (@code{gnatbind}) -Enable leap seconds support in @code{Ada.Calendar} and its children. +@item @code{-z} -@item -z -@cindex @option{-z} (@code{gnatbind}) No main subprogram. @end table -@noindent -You may obtain this listing of switches by running @code{gnatbind} with +You may obtain this listing of switches by running @cite{gnatbind} with no arguments. -@node Consistency-Checking Modes -@subsection Consistency-Checking Modes +@menu +* Consistency-Checking Modes:: +* Binder Error Message Control:: +* Elaboration Control:: +* Output Control:: +* Dynamic Allocation Control:: +* Binding with Non-Ada Main Programs:: +* Binding Programs with No Main Subprogram:: + +@end menu + +@node Consistency-Checking Modes,Binder Error Message Control,,Switches for gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat consistency-checking-modes}@anchor{126}@anchor{gnat_ugn/building_executable_programs_with_gnat id34}@anchor{127} +@subsubsection Consistency-Checking Modes -@noindent -As described earlier, by default @code{gnatbind} checks + +As described earlier, by default @cite{gnatbind} checks that object files are consistent with one another and are consistent with any source files it can locate. The following switches control binder access to sources. -@table @option -@c !sort! -@item -s -@cindex @option{-s} (@code{gnatbind}) +@quotation + +@geindex -s (gnatbind) +@end quotation + + +@table @asis + +@item @code{-s} + Require source files to be present. In this mode, the binder must be able to locate all source files that are referenced, in order to check their consistency. In normal mode, if a source file cannot be located it is simply ignored. If you specify this switch, a missing source file is an error. -@item -Wx@var{e} -@cindex @option{-Wx} (@code{gnatbind}) +@geindex -Wx (gnatbind) + +@item @code{-Wx@emph{e}} + Override default wide character encoding for standard Text_IO files. Normally the default wide character encoding method used for standard [Wide_[Wide_]]Text_IO files is taken from the encoding specified for the main source input (see description of switch -@option{-gnatWx} for the compiler). The +@emph{-gnatWx} for the compiler). The use of this switch for the binder (which has the same set of possible arguments) overrides this default as specified. -@item -x -@cindex @option{-x} (@code{gnatbind}) +@geindex -x (gnatbind) + +@item @code{-x} + Exclude source files. In this mode, the binder only checks that ALI files are consistent with one another. Source files are not accessed. The binder runs faster in this mode, and there is still a guarantee that @@ -8319,234 +15521,308 @@ the resulting program is self-consistent. If a source file has been edited since it was last compiled, and you specify this switch, the binder will not detect that the object file is out of date with respect to the source file. Note that this is the -mode that is automatically used by @command{gnatmake} because in this +mode that is automatically used by @emph{gnatmake} because in this case the checking against sources has already been performed by -@command{gnatmake} in the course of compilation (i.e.@: before binding). - +@emph{gnatmake} in the course of compilation (i.e., before binding). @end table -@node Binder Error Message Control -@subsection Binder Error Message Control +@node Binder Error Message Control,Elaboration Control,Consistency-Checking Modes,Switches for gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat id35}@anchor{128}@anchor{gnat_ugn/building_executable_programs_with_gnat binder-error-message-control}@anchor{129} +@subsubsection Binder Error Message Control + -@noindent The following switches provide control over the generation of error messages from the binder: -@table @option -@c !sort! -@item -v -@cindex @option{-v} (@code{gnatbind}) +@quotation + +@geindex -v (gnatbind) +@end quotation + + +@table @asis + +@item @code{-v} + Verbose mode. In the normal mode, brief error messages are generated to -@file{stderr}. If this switch is present, a header is written -to @file{stdout} and any error messages are directed to @file{stdout}. -All that is written to @file{stderr} is a brief summary message. +@code{stderr}. If this switch is present, a header is written +to @code{stdout} and any error messages are directed to @code{stdout}. +All that is written to @code{stderr} is a brief summary message. + +@geindex -b (gnatbind) -@item -b -@cindex @option{-b} (@code{gnatbind}) -Generate brief error messages to @file{stderr} even if verbose mode is +@item @code{-b} + +Generate brief error messages to @code{stderr} even if verbose mode is specified. This is relevant only when used with the -@option{-v} switch. +@emph{-v} switch. + +@geindex -m (gnatbind) -@item -m@var{n} -@cindex @option{-m} (@code{gnatbind}) -Limits the number of error messages to @var{n}, a decimal integer in the +@item @code{-m@emph{n}} + +Limits the number of error messages to @cite{n}, a decimal integer in the range 1-999. The binder terminates immediately if this limit is reached. -@item -M@var{xxx} -@cindex @option{-M} (@code{gnatbind}) -Renames the generated main program from @code{main} to @code{xxx}. +@geindex -M (gnatbind) + +@item @code{-M@emph{xxx}} + +Renames the generated main program from @cite{main} to @cite{xxx}. This is useful in the case of some cross-building environments, where the actual main program is separate from the one generated -by @code{gnatbind}. +by @cite{gnatbind}. + +@geindex -ws (gnatbind) + +@geindex Warnings + +@item @code{-ws} -@item -ws -@cindex @option{-ws} (@code{gnatbind}) -@cindex Warnings Suppress all warning messages. -@item -we -@cindex @option{-we} (@code{gnatbind}) +@geindex -we (gnatbind) + +@item @code{-we} + Treat any warning messages as fatal errors. +@geindex -t (gnatbind) + +@geindex Time stamp checks +@geindex in binder + +@geindex Binder consistency checks + +@geindex Consistency checks +@geindex in binder + +@item @code{-t} -@item -t -@cindex @option{-t} (@code{gnatbind}) -@cindex Time stamp checks, in binder -@cindex Binder consistency checks -@cindex Consistency checks, in binder The binder performs a number of consistency checks including: -@itemize @bullet -@item + +@itemize * + +@item Check that time stamps of a given source unit are consistent -@item + +@item Check that checksums of a given source unit are consistent -@item -Check that consistent versions of @code{GNAT} were used for compilation -@item + +@item +Check that consistent versions of @cite{GNAT} were used for compilation + +@item Check consistency of configuration pragmas as required @end itemize -@noindent Normally failure of such checks, in accordance with the consistency requirements of the Ada Reference Manual, causes error messages to be generated which abort the binder and prevent the output of a binder file and subsequent link to obtain an executable. -The @option{-t} switch converts these error messages +The @emph{-t} switch converts these error messages into warnings, so that binding and linking can continue to completion even in the presence of such errors. The result may be a failed link (due to missing symbols), or a non-functional executable which has undefined semantics. -@emph{This means that -@option{-t} should be used only in unusual situations, -with extreme care.} + +@cartouche +@quotation Note +This means that @emph{-t} should be used only in unusual situations, +with extreme care. +@end quotation +@end cartouche @end table -@node Elaboration Control -@subsection Elaboration Control +@node Elaboration Control,Output Control,Binder Error Message Control,Switches for gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat id36}@anchor{12a}@anchor{gnat_ugn/building_executable_programs_with_gnat elaboration-control}@anchor{12b} +@subsubsection Elaboration Control + -@noindent The following switches provide additional control over the elaboration -order. For full details see @ref{Elaboration Order Handling in GNAT}. +order. For full details see @ref{11,,Elaboration Order Handling in GNAT}. + +@quotation + +@geindex -p (gnatbind) +@end quotation + + +@table @asis + +@item @code{-p} -@table @option -@item -p -@cindex @option{-p} (@code{gnatbind}) Normally the binder attempts to choose an elaboration order that is likely to minimize the likelihood of an elaboration order error resulting -in raising a @code{Program_Error} exception. This switch reverses the +in raising a @cite{Program_Error} exception. This switch reverses the action of the binder, and requests that it deliberately choose an order that is likely to maximize the likelihood of an elaboration error. This is useful in ensuring portability and avoiding dependence on accidental fortuitous elaboration ordering. -Normally it only makes sense to use the @option{-p} +Normally it only makes sense to use the @emph{-p} switch if dynamic -elaboration checking is used (@option{-gnatE} switch used for compilation). +elaboration checking is used (@emph{-gnatE} switch used for compilation). This is because in the default static elaboration mode, all necessary -@code{Elaborate} and @code{Elaborate_All} pragmas are implicitly inserted. +@cite{Elaborate} and @cite{Elaborate_All} pragmas are implicitly inserted. These implicit pragmas are still respected by the binder in -@option{-p} mode, so a +@emph{-p} mode, so a safe elaboration order is assured. -Note that @option{-p} is not intended for +Note that @emph{-p} is not intended for production use; it is more for debugging/experimental use. @end table -@node Output Control -@subsection Output Control +@node Output Control,Dynamic Allocation Control,Elaboration Control,Switches for gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat output-control}@anchor{12c}@anchor{gnat_ugn/building_executable_programs_with_gnat id37}@anchor{12d} +@subsubsection Output Control + -@noindent The following switches allow additional control over the output generated by the binder. -@table @option -@c !sort! +@quotation + +@geindex -c (gnatbind) +@end quotation + + +@table @asis + +@item @code{-c} -@item -c -@cindex @option{-c} (@code{gnatbind}) Check only. Do not generate the binder output file. In this mode the binder performs all error checks but does not generate an output file. -@item -e -@cindex @option{-e} (@code{gnatbind}) +@geindex -e (gnatbind) + +@item @code{-e} + Output complete list of elaboration-order dependencies, showing the reason for each dependency. This output can be rather extensive but may be useful in diagnosing problems with elaboration order. The output is -written to @file{stdout}. +written to @code{stdout}. + +@geindex -h (gnatbind) + +@item @code{-h} -@item -h -@cindex @option{-h} (@code{gnatbind}) -Output usage information. The output is written to @file{stdout}. +Output usage information. The output is written to @code{stdout}. -@item -K -@cindex @option{-K} (@code{gnatbind}) -Output linker options to @file{stdout}. Includes library search paths, +@geindex -K (gnatbind) + +@item @code{-K} + +Output linker options to @code{stdout}. Includes library search paths, contents of pragmas Ident and Linker_Options, and libraries added -by @code{gnatbind}. +by @cite{gnatbind}. + +@geindex -l (gnatbind) + +@item @code{-l} -@item -l -@cindex @option{-l} (@code{gnatbind}) -Output chosen elaboration order. The output is written to @file{stdout}. +Output chosen elaboration order. The output is written to @code{stdout}. + +@geindex -O (gnatbind) + +@item @code{-O} -@item -O -@cindex @option{-O} (@code{gnatbind}) Output full names of all the object files that must be linked to provide -the Ada component of the program. The output is written to @file{stdout}. +the Ada component of the program. The output is written to @code{stdout}. This list includes the files explicitly supplied and referenced by the user as well as implicitly referenced run-time unit files. The latter are omitted if the corresponding units reside in shared libraries. The directory names for the run-time units depend on the system configuration. -@item -o @var{file} -@cindex @option{-o} (@code{gnatbind}) -Set name of output file to @var{file} instead of the normal -@file{b~@var{mainprog}.adb} default. Note that @var{file} denote the Ada +@geindex -o (gnatbind) + +@item @code{-o @emph{file}} + +Set name of output file to @cite{file} instead of the normal +@code{b~`mainprog}.adb` default. Note that @cite{file} denote the Ada binder generated body filename. Note that if this option is used, then linking must be done manually. It is not possible to use gnatlink in this case, since it cannot locate the binder file. -@item -r -@cindex @option{-r} (@code{gnatbind}) -Generate list of @code{pragma Restrictions} that could be applied to +@geindex -r (gnatbind) + +@item @code{-r} + +Generate list of @cite{pragma Restrictions} that could be applied to the current unit. This is useful for code audit purposes, and also may be used to improve code generation in some cases. - @end table -@node Dynamic Allocation Control -@subsection Dynamic Allocation Control +@node Dynamic Allocation Control,Binding with Non-Ada Main Programs,Output Control,Switches for gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat dynamic-allocation-control}@anchor{124}@anchor{gnat_ugn/building_executable_programs_with_gnat id38}@anchor{12e} +@subsubsection Dynamic Allocation Control + -@noindent -The heap control switches -- @option{-H32} and @option{-H64} -- +The heap control switches -- @emph{-H32} and @emph{-H64} -- determine whether dynamic allocation uses 32-bit or 64-bit memory. -They only affect compiler-generated allocations via @code{__gnat_malloc}; -explicit calls to @code{malloc} and related functions from the C +They only affect compiler-generated allocations via @cite{__gnat_malloc}; +explicit calls to @cite{malloc} and related functions from the C run-time library are unaffected. -@table @option -@item -H32 + +@table @asis + +@item @code{-H32} + Allocate memory on 32-bit heap -@item -H64 +@item @code{-H64} + Allocate memory on 64-bit heap. This is the default -unless explicitly overridden by a @code{'Size} clause on the access type. +unless explicitly overridden by a @cite{'Size} clause on the access type. @end table -@noindent These switches are only effective on VMS platforms. +@node Binding with Non-Ada Main Programs,Binding Programs with No Main Subprogram,Dynamic Allocation Control,Switches for gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat binding-with-non-ada-main-programs}@anchor{ba}@anchor{gnat_ugn/building_executable_programs_with_gnat id39}@anchor{12f} +@subsubsection Binding with Non-Ada Main Programs -@node Binding with Non-Ada Main Programs -@subsection Binding with Non-Ada Main Programs -@noindent -In our description so far we have assumed that the main +The description so far has assumed that the main program is in Ada, and that the task of the binder is to generate a -corresponding function @code{main} that invokes this Ada main +corresponding function @cite{main} that invokes this Ada main program. GNAT also supports the building of executable programs where the main program is not in Ada, but some of the called routines are -written in Ada and compiled using GNAT (@pxref{Mixed Language Programming}). +written in Ada and compiled using GNAT (@ref{46,,Mixed Language Programming}). The following switch is used in this situation: -@table @option -@item -n -@cindex @option{-n} (@code{gnatbind}) +@quotation + +@geindex -n (gnatbind) +@end quotation + + +@table @asis + +@item @code{-n} + No main program. The main program is not in Ada. @end table -@noindent In this case, most of the functions of the binder are still required, but instead of generating a main program, the binder generates a file containing the following callable routines: -@table @code -@item adainit -@findex adainit +@quotation + +@geindex adainit + + +@table @asis + +@item @emph{adainit} + You must call this routine to initialize the Ada part of the program by -calling the necessary elaboration routines. A call to @code{adainit} is +calling the necessary elaboration routines. A call to @cite{adainit} is required before the first call to an Ada subprogram. Note that it is assumed that the basic execution environment must be setup @@ -8556,32 +15832,43 @@ floating-point operations, then the FPU must be setup in an appropriate manner. For the case of the x86, for example, full precision mode is required. The procedure GNAT.Float_Control.Reset may be used to ensure that the FPU is in the right state. +@end table + +@geindex adafinal + + +@table @asis + +@item @emph{adafinal} -@item adafinal -@findex adafinal You must call this routine to perform any library-level finalization -required by the Ada subprograms. A call to @code{adafinal} is required +required by the Ada subprograms. A call to @cite{adafinal} is required after the last call to an Ada subprogram, and before the program terminates. @end table +@end quotation + +@geindex -n (gnatbind) + +@geindex Binder +@geindex multiple input files -@noindent -If the @option{-n} switch -@cindex @option{-n} (@command{gnatbind}) -@cindex Binder, multiple input files +If the @emph{-n} switch is given, more than one ALI file may appear on -the command line for @code{gnatbind}. The normal @dfn{closure} +the command line for @cite{gnatbind}. The normal @emph{closure} calculation is performed for each of the specified units. Calculating the closure means finding out the set of units involved by tracing -@code{with} references. The reason it is necessary to be able to +@emph{with} references. The reason it is necessary to be able to specify more than one ALI file is that a given program may invoke two or more quite separate groups of Ada units. The binder takes the name of its output file from the last specified ALI -file, unless overridden by the use of the @option{-o file}. -@cindex @option{-o} (@command{gnatbind}) +file, unless overridden by the use of the @emph{-o file}. + +@geindex -o (gnatbind) + The output is an Ada unit in source form that can be compiled with GNAT. -This compilation occurs automatically as part of the @command{gnatlink} +This compilation occurs automatically as part of the @emph{gnatlink} processing. Currently the GNAT run time requires a FPU using 80 bits mode @@ -8591,19 +15878,27 @@ include float computation, float input and output) in the Ada code. A side effect is that this could be the wrong mode for the foreign code where floating point computation could be broken after this call. -@node Binding Programs with No Main Subprogram -@subsection Binding Programs with No Main Subprogram +@node Binding Programs with No Main Subprogram,,Binding with Non-Ada Main Programs,Switches for gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat binding-programs-with-no-main-subprogram}@anchor{130}@anchor{gnat_ugn/building_executable_programs_with_gnat id40}@anchor{131} +@subsubsection Binding Programs with No Main Subprogram + -@noindent It is possible to have an Ada program which does not have a main subprogram. This program will call the elaboration routines of all the packages, then the finalization routines. The following switch is used to bind programs organized in this manner: -@table @option -@item -z -@cindex @option{-z} (@code{gnatbind}) +@quotation + +@geindex -z (gnatbind) +@end quotation + + +@table @asis + +@item @code{-z} + Normally the binder checks that the unit name given on the command line corresponds to a suitable main subprogram. When this switch is used, a list of ALI files can be given, and the execution of the program @@ -8611,109 +15906,128 @@ consists of elaboration of these units in an appropriate order. Note that the default wide character encoding method for standard Text_IO files is always set to Brackets if this switch is set (you can use the binder switch -@option{-Wx} to override this default). +@emph{-Wx} to override this default). @end table -@node Command-Line Access -@section Command-Line Access +@node Command-Line Access,Search Paths for gnatbind,Switches for gnatbind,Binding with gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat id41}@anchor{132}@anchor{gnat_ugn/building_executable_programs_with_gnat command-line-access}@anchor{133} +@subsection Command-Line Access + -@noindent -The package @code{Ada.Command_Line} provides access to the command-line +The package @cite{Ada.Command_Line} provides access to the command-line arguments and program name. In order for this interface to operate correctly, the two variables -@smallexample -@group +@example int gnat_argc; char **gnat_argv; -@end group -@end smallexample +@end example + +@geindex gnat_argv + +@geindex gnat_argc -@noindent -@findex gnat_argv -@findex gnat_argc are declared in one of the GNAT library routines. These variables must -be set from the actual @code{argc} and @code{argv} values passed to the -main program. With no @option{n} present, @code{gnatbind} +be set from the actual @cite{argc} and @cite{argv} values passed to the +main program. With no @emph{n} present, @cite{gnatbind} generates the C main program to automatically set these variables. -If the @option{n} switch is used, there is no automatic way to +If the @emph{n} switch is used, there is no automatic way to set these variables. If they are not set, the procedures in -@code{Ada.Command_Line} will not be available, and any attempt to use -them will raise @code{Constraint_Error}. If command line access is -required, your main program must set @code{gnat_argc} and -@code{gnat_argv} from the @code{argc} and @code{argv} values passed to +@cite{Ada.Command_Line} will not be available, and any attempt to use +them will raise @cite{Constraint_Error}. If command line access is +required, your main program must set @cite{gnat_argc} and +@cite{gnat_argv} from the @cite{argc} and @cite{argv} values passed to it. -@node Search Paths for gnatbind -@section Search Paths for @code{gnatbind} +@node Search Paths for gnatbind,Examples of gnatbind Usage,Command-Line Access,Binding with gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat search-paths-for-gnatbind}@anchor{91}@anchor{gnat_ugn/building_executable_programs_with_gnat id42}@anchor{134} +@subsection Search Paths for @cite{gnatbind} + -@noindent The binder takes the name of an ALI file as its argument and needs to locate source files as well as other ALI files to verify object consistency. -For source files, it follows exactly the same search rules as @command{gcc} -(@pxref{Search Paths and the Run-Time Library (RTL)}). For ALI files the +For source files, it follows exactly the same search rules as @emph{gcc} +(see @ref{8e,,Search Paths and the Run-Time Library (RTL)}). For ALI files the directories searched are: -@enumerate -@item + +@itemize * + +@item The directory containing the ALI file named in the command line, unless -the switch @option{-I-} is specified. +the switch @emph{-I-} is specified. -@item -All directories specified by @option{-I} -switches on the @code{gnatbind} +@item +All directories specified by @emph{-I} +switches on the @cite{gnatbind} command line, in the order given. -@item -@findex ADA_PRJ_OBJECTS_FILE -Each of the directories listed in the text file whose name is given -by the @env{ADA_PRJ_OBJECTS_FILE} environment variable. +@geindex ADA_PRJ_OBJECTS_FILE -@noindent -@env{ADA_PRJ_OBJECTS_FILE} is normally set by gnatmake or by the gnat +@item +Each of the directories listed in the text file whose name is given +by the +@geindex ADA_PRJ_OBJECTS_FILE +@geindex environment variable; ADA_PRJ_OBJECTS_FILE +@code{ADA_PRJ_OBJECTS_FILE} environment variable. + +@geindex ADA_PRJ_OBJECTS_FILE +@geindex environment variable; ADA_PRJ_OBJECTS_FILE +@code{ADA_PRJ_OBJECTS_FILE} is normally set by gnatmake or by the gnat driver when project files are used. It should not normally be set by other means. -@item -@findex ADA_OBJECTS_PATH +@geindex ADA_OBJECTS_PATH + +@item Each of the directories listed in the value of the -@env{ADA_OBJECTS_PATH} environment variable. +@geindex ADA_OBJECTS_PATH +@geindex environment variable; ADA_OBJECTS_PATH +@code{ADA_OBJECTS_PATH} environment variable. Construct this value -exactly as the @env{PATH} environment variable: a list of directory +exactly as the +@geindex PATH +@geindex environment variable; PATH +@code{PATH} environment variable: a list of directory names separated by colons (semicolons when working with the NT version of GNAT). -@item -The content of the @file{ada_object_path} file which is part of the GNAT +@item +The content of the @code{ada_object_path} file which is part of the GNAT installation tree and is used to store standard libraries such as the -GNAT Run Time Library (RTL) unless the switch @option{-nostdlib} is -specified. -@ref{Installing a library} -@end enumerate +GNAT Run Time Library (RTL) unless the switch @emph{-nostdlib} is +specified. See @ref{8b,,Installing a library} +@end itemize + +@geindex -I (gnatbind) -@noindent -In the binder the switch @option{-I} -@cindex @option{-I} (@command{gnatbind}) +@geindex -aI (gnatbind) + +@geindex -aO (gnatbind) + +In the binder the switch @emph{-I} is used to specify both source and -library file paths. Use @option{-aI} -@cindex @option{-aI} (@command{gnatbind}) +library file paths. Use @emph{-aI} instead if you want to specify -source paths only, and @option{-aO} -@cindex @option{-aO} (@command{gnatbind}) +source paths only, and @emph{-aO} if you want to specify library paths only. This means that for the binder -@option{-I}@var{dir} is equivalent to -@option{-aI}@var{dir} -@option{-aO}@var{dir}. +@code{-I@emph{dir}} is equivalent to +@code{-aI@emph{dir}} +@code{-aO`@emph{dir}}. The binder generates the bind file (a C language source file) in the current working directory. -@findex Ada -@findex System -@findex Interfaces -@findex GNAT -The packages @code{Ada}, @code{System}, and @code{Interfaces} and their +@geindex Ada + +@geindex System + +@geindex Interfaces + +@geindex GNAT + +The packages @cite{Ada}, @cite{System}, and @cite{Interfaces} and their children make up the GNAT Run-Time Library, together with the package GNAT and its children, which contain a set of useful additional library functions provided by GNAT. The sources for these units are @@ -8729,7888 +16043,7360 @@ Besides simplifying access to the RTL, a major use of search paths is in compiling sources from multiple directories. This can make development environments much more flexible. -@node Examples of gnatbind Usage -@section Examples of @code{gnatbind} Usage +@node Examples of gnatbind Usage,,Search Paths for gnatbind,Binding with gnatbind +@anchor{gnat_ugn/building_executable_programs_with_gnat examples-of-gnatbind-usage}@anchor{135}@anchor{gnat_ugn/building_executable_programs_with_gnat id43}@anchor{136} +@subsection Examples of @cite{gnatbind} Usage + + +Here are some examples of @cite{gnatbind} invovations: -@noindent -This section contains a number of examples of using the GNAT binding -utility @code{gnatbind}. +@quotation + +@example +gnatbind hello +@end example -@table @code -@item gnatbind hello -The main program @code{Hello} (source program in @file{hello.adb}) is +The main program @cite{Hello} (source program in @code{hello.adb}) is bound using the standard switch settings. The generated main program is -@file{b~hello.adb}. This is the normal, default use of the binder. +@code{b~hello.adb}. This is the normal, default use of the binder. -@item gnatbind hello -o mainprog.adb -The main program @code{Hello} (source program in @file{hello.adb}) is +@example +gnatbind hello -o mainprog.adb +@end example + +The main program @cite{Hello} (source program in @code{hello.adb}) is bound using the standard switch settings. The generated main program is -@file{mainprog.adb} with the associated spec in -@file{mainprog.ads}. Note that you must specify the body here not the +@code{mainprog.adb} with the associated spec in +@code{mainprog.ads}. Note that you must specify the body here not the spec. Note that if this option is used, then linking must be done manually, since gnatlink will not be able to find the generated file. -@end table +@end quotation + +@node Linking with gnatlink,Using the GNU make Utility,Binding with gnatbind,Building Executable Programs with GNAT +@anchor{gnat_ugn/building_executable_programs_with_gnat id44}@anchor{137}@anchor{gnat_ugn/building_executable_programs_with_gnat linking-with-gnatlink}@anchor{20} +@section Linking with @emph{gnatlink} -@c ------------------------------------ -@node Linking with gnatlink -@chapter Linking with @command{gnatlink} -@c ------------------------------------ -@findex gnatlink -@noindent -This chapter discusses @command{gnatlink}, a tool that links +@c index: ! gnatlink + +This chapter discusses @emph{gnatlink}, a tool that links an Ada program and builds an executable file. This utility -invokes the system linker (via the @command{gcc} command) +invokes the system linker (via the @emph{gcc} command) with a correct list of object files and library references. -@command{gnatlink} automatically determines the list of files and +@emph{gnatlink} automatically determines the list of files and references for the Ada part of a program. It uses the binder file -generated by the @command{gnatbind} to determine this list. +generated by the @emph{gnatbind} to determine this list. -Note: to invoke @code{gnatlink} with a project file, use the @code{gnat} -driver (see @ref{The GNAT Driver and Project Files}). +Note: to invoke @cite{gnatlink} with a project file, use the @cite{gnat} +driver (see @ref{11f,,The GNAT Driver and Project Files}). @menu -* Running gnatlink:: -* Switches for gnatlink:: +* Running gnatlink:: +* Switches for gnatlink:: + @end menu -@node Running gnatlink -@section Running @command{gnatlink} +@node Running gnatlink,Switches for gnatlink,,Linking with gnatlink +@anchor{gnat_ugn/building_executable_programs_with_gnat id45}@anchor{138}@anchor{gnat_ugn/building_executable_programs_with_gnat running-gnatlink}@anchor{139} +@subsection Running @emph{gnatlink} -@noindent -The form of the @command{gnatlink} command is -@smallexample -@c $ gnatlink @ovar{switches} @var{mainprog}@r{[}.ali@r{]} -@c @ovar{non-Ada objects} @ovar{linker options} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatlink @r{[}@var{switches}@r{]} @var{mainprog}@r{[}.ali@r{]} - @r{[}@var{non-Ada objects}@r{]} @r{[}@var{linker options}@r{]} +The form of the @emph{gnatlink} command is -@end smallexample +@example +$ gnatlink [`switches`] `mainprog`[.ali] + [`non-Ada objects`] [`linker options`] +@end example -@noindent -The arguments of @command{gnatlink} (switches, main @file{ALI} file, +The arguments of @emph{gnatlink} (switches, main @code{ALI} file, non-Ada objects or linker options) may be in any order, provided that no non-Ada object may -be mistaken for a main @file{ALI} file. -Any file name @file{F} without the @file{.ali} -extension will be taken as the main @file{ALI} file if a file exists -whose name is the concatenation of @file{F} and @file{.ali}. - -@noindent -@file{@var{mainprog}.ali} references the ALI file of the main program. -The @file{.ali} extension of this file can be omitted. From this -reference, @command{gnatlink} locates the corresponding binder file -@file{b~@var{mainprog}.adb} and, using the information in this file along +be mistaken for a main @code{ALI} file. +Any file name @code{F} without the @code{.ali} +extension will be taken as the main @code{ALI} file if a file exists +whose name is the concatenation of @code{F} and @code{.ali}. + +@code{mainprog.ali} references the ALI file of the main program. +The @code{.ali} extension of this file can be omitted. From this +reference, @emph{gnatlink} locates the corresponding binder file +@code{b~mainprog.adb} and, using the information in this file along with the list of non-Ada objects and linker options, constructs a linker command file to create the executable. -The arguments other than the @command{gnatlink} switches and the main -@file{ALI} file are passed to the linker uninterpreted. +The arguments other than the @emph{gnatlink} switches and the main +@code{ALI} file are passed to the linker uninterpreted. They typically include the names of object files for units written in other languages than Ada and any library references required to resolve references in any of these foreign language -units, or in @code{Import} pragmas in any Ada units. +units, or in @cite{Import} pragmas in any Ada units. -@var{linker options} is an optional list of linker specific +@cite{linker options} is an optional list of linker specific switches. -The default linker called by gnatlink is @command{gcc} which in +The default linker called by gnatlink is @emph{gcc} which in turn calls the appropriate system linker. -One useful option for the linker is @option{-s}: it reduces the size of the +One useful option for the linker is @emph{-s}: it reduces the size of the executable by removing all symbol table and relocation information from the executable. -Standard options for the linker such as @option{-lmy_lib} or -@option{-Ldir} can be added as is. +Standard options for the linker such as @emph{-lmy_lib} or +@emph{-Ldir} can be added as is. For options that are not recognized by -@command{gcc} as linker options, use the @command{gcc} switches -@option{-Xlinker} or @option{-Wl,}. +@emph{gcc} as linker options, use the @emph{gcc} switches +@emph{-Xlinker} or @emph{-Wl,}. Refer to the GCC documentation for details. Here is an example showing how to generate a linker map: -@smallexample +@example $ gnatlink my_prog -Wl,-Map,MAPFILE -@end smallexample +@end example -Using @var{linker options} it is possible to set the program stack and +Using @cite{linker options} it is possible to set the program stack and heap size. -See @ref{Setting Stack Size from gnatlink} and -@ref{Setting Heap Size from gnatlink}. +See @ref{13a,,Setting Stack Size from gnatlink} and +@ref{13b,,Setting Heap Size from gnatlink}. -@command{gnatlink} determines the list of objects required by the Ada +@emph{gnatlink} determines the list of objects required by the Ada program and prepends them to the list of objects passed to the linker. -@command{gnatlink} also gathers any arguments set by the use of -@code{pragma Linker_Options} and adds them to the list of arguments +@emph{gnatlink} also gathers any arguments set by the use of +@cite{pragma Linker_Options} and adds them to the list of arguments presented to the linker. +@node Switches for gnatlink,,Running gnatlink,Linking with gnatlink +@anchor{gnat_ugn/building_executable_programs_with_gnat id46}@anchor{13c}@anchor{gnat_ugn/building_executable_programs_with_gnat switches-for-gnatlink}@anchor{13d} +@subsection Switches for @emph{gnatlink} -@node Switches for gnatlink -@section Switches for @command{gnatlink} -@noindent -The following switches are available with the @command{gnatlink} utility: +The following switches are available with the @emph{gnatlink} utility: -@table @option -@c !sort! +@geindex --version (gnatlink) + + +@table @asis + +@item @code{--version} -@item --version -@cindex @option{--version} @command{gnatlink} Display Copyright and version, then exit disregarding all other options. +@end table + +@geindex --help (gnatlink) -@item --help -@cindex @option{--help} @command{gnatlink} -If @option{--version} was not used, display usage, then exit disregarding + +@table @asis + +@item @code{--help} + +If @emph{--version} was not used, display usage, then exit disregarding all other options. +@end table + +@geindex Command line length + +@geindex -f (gnatlink) + + +@table @asis -@item -f -@cindex Command line length -@cindex @option{-f} (@command{gnatlink}) -On some targets, the command line length is limited, and @command{gnatlink} +@item @code{-f} + +On some targets, the command line length is limited, and @emph{gnatlink} will generate a separate file for the linker if the list of object files is too long. -The @option{-f} switch forces this file +The @emph{-f} switch forces this file to be generated even if the limit is not exceeded. This is useful in some cases to deal with special situations where the command line length is exceeded. +@end table + +@geindex Debugging information +@geindex including + +@geindex -g (gnatlink) + + +@table @asis + +@item @code{-g} -@item -g -@cindex Debugging information, including -@cindex @option{-g} (@command{gnatlink}) The option to include debugging information causes the Ada bind file (in -other words, @file{b~@var{mainprog}.adb}) to be compiled with -@option{-g}. -In addition, the binder does not delete the @file{b~@var{mainprog}.adb}, -@file{b~@var{mainprog}.o} and @file{b~@var{mainprog}.ali} files. -Without @option{-g}, the binder removes these files by -default. The same procedure apply if a C bind file was generated using -@option{-C} @code{gnatbind} option, in this case the filenames -are @file{b_@var{mainprog}.c} and @file{b_@var{mainprog}.o}. - -@item -n -@cindex @option{-n} (@command{gnatlink}) +other words, @code{b~mainprog.adb}) to be compiled with @emph{-g}. +In addition, the binder does not delete the @code{b~mainprog.adb}, +@code{b~mainprog.o} and @code{b~mainprog.ali} files. +Without @emph{-g}, the binder removes these files by default. +@end table + +@geindex -n (gnatlink) + + +@table @asis + +@item @code{-n} + Do not compile the file generated by the binder. This may be used when a link is rerun with different options, but there is no need to recompile the binder file. +@end table -@item -v -@cindex @option{-v} (@command{gnatlink}) -Causes additional information to be output, including a full list of the -included object files. This switch option is most useful when you want +@geindex -v (gnatlink) + + +@table @asis + +@item @code{-v} + +Verbose mode. Causes additional information to be output, including a full +list of the included object files. +This switch option is most useful when you want to see what set of object files are being used in the link step. +@end table + +@geindex -v -v (gnatlink) + + +@table @asis + +@item @code{-v -v} -@item -v -v -@cindex @option{-v -v} (@command{gnatlink}) Very verbose mode. Requests that the compiler operate in verbose mode when it compiles the binder file, and that the system linker run in verbose mode. +@end table + +@geindex -o (gnatlink) + + +@table @asis -@item -o @var{exec-name} -@cindex @option{-o} (@command{gnatlink}) -@var{exec-name} specifies an alternate name for the generated +@item @code{-o @emph{exec-name}} + +@cite{exec-name} specifies an alternate name for the generated executable program. If this switch is omitted, the executable has the same -name as the main unit. For example, @code{gnatlink try.ali} creates -an executable called @file{try}. +name as the main unit. For example, @cite{gnatlink try.ali} creates +an executable called @code{try}. +@end table + +@geindex -b (gnatlink) + -@item -b @var{target} -@cindex @option{-b} (@command{gnatlink}) -Compile your program to run on @var{target}, which is the name of a +@table @asis + +@item @code{-b @emph{target}} + +Compile your program to run on @cite{target}, which is the name of a system configuration. You must have a GNAT cross-compiler built if -@var{target} is not the same as your host system. +@cite{target} is not the same as your host system. +@end table -@item -B@var{dir} -@cindex @option{-B} (@command{gnatlink}) -Load compiler executables (for example, @code{gnat1}, the Ada compiler) -from @var{dir} instead of the default location. Only use this switch +@geindex -B (gnatlink) + + +@table @asis + +@item @code{-B@emph{dir}} + +Load compiler executables (for example, @cite{gnat1}, the Ada compiler) +from @cite{dir} instead of the default location. Only use this switch when multiple versions of the GNAT compiler are available. -@xref{Directory Options,,, gcc, The GNU Compiler Collection}, -for further details. You would normally use the @option{-b} or -@option{-V} switch instead. +See the @cite{Directory Options} section in @cite{The_GNU_Compiler_Collection} +for further details. You would normally use the @emph{-b} or +@emph{-V} switch instead. +@end table + +@geindex -M (gnatlink) + + +@table @asis + +@item @code{-M} -@item -M When linking an executable, create a map file. The name of the map file has the same name as the executable with extension ".map". +@end table + +@geindex -M= (gnatlink) + + +@table @asis + +@item @code{-M=@emph{mapfile}} -@item -M=mapfile When linking an executable, create a map file. The name of the map file is -"mapfile". +@cite{mapfile}. +@end table + +@geindex --GCC=compiler_name (gnatlink) + + +@table @asis + +@item @code{--GCC=@emph{compiler_name}} -@item --GCC=@var{compiler_name} -@cindex @option{--GCC=compiler_name} (@command{gnatlink}) Program used for compiling the binder file. The default is -@command{gcc}. You need to use quotes around @var{compiler_name} if -@code{compiler_name} contains spaces or other separator characters. -As an example @option{--GCC="foo -x -y"} will instruct @command{gnatlink} to -use @code{foo -x -y} as your compiler. Note that switch @option{-c} is always +@code{gcc}. You need to use quotes around @cite{compiler_name} if +@cite{compiler_name} contains spaces or other separator characters. +As an example @code{--GCC="foo -x -y"} will instruct @emph{gnatlink} to +use @code{foo -x -y} as your compiler. Note that switch @code{-c} is always inserted after your command name. Thus in the above example the compiler -command that will be used by @command{gnatlink} will be @code{foo -c -x -y}. +command that will be used by @emph{gnatlink} will be @code{foo -c -x -y}. A limitation of this syntax is that the name and path name of the executable itself must not include any embedded spaces. If the compiler executable is different from the default one (gcc or <prefix>-gcc), then the back-end switches in the ALI file are not used to compile the binder generated source. -For example, this is the case with @option{--GCC="foo -x -y"}. But the back end -switches will be used for @option{--GCC="gcc -gnatv"}. If several -@option{--GCC=compiler_name} are used, only the last @var{compiler_name} +For example, this is the case with @code{--GCC="foo -x -y"}. But the back end +switches will be used for @code{--GCC="gcc -gnatv"}. If several +@code{--GCC=compiler_name} are used, only the last @cite{compiler_name} is taken into account. However, all the additional switches are also taken into account. Thus, -@option{--GCC="foo -x -y" --GCC="bar -z -t"} is equivalent to -@option{--GCC="bar -x -y -z -t"}. +@code{--GCC="foo -x -y" --GCC="bar -z -t"} is equivalent to +@code{--GCC="bar -x -y -z -t"}. +@end table -@item --LINK=@var{name} -@cindex @option{--LINK=} (@command{gnatlink}) -@var{name} is the name of the linker to be invoked. This is especially +@geindex --LINK= (gnatlink) + + +@table @asis + +@item @code{--LINK=@emph{name}} + +@cite{name} is the name of the linker to be invoked. This is especially useful in mixed language programs since languages such as C++ require their own linker to be used. When this switch is omitted, the default -name for the linker is @command{gcc}. When this switch is used, the -specified linker is called instead of @command{gcc} with exactly the same -parameters that would have been passed to @command{gcc} so if the desired +name for the linker is @emph{gcc}. When this switch is used, the +specified linker is called instead of @emph{gcc} with exactly the same +parameters that would have been passed to @emph{gcc} so if the desired linker requires different parameters it is necessary to use a wrapper script that massages the parameters before invoking the real linker. It may be useful to control the exact invocation by using the verbose switch. +@end table +@node Using the GNU make Utility,,Linking with gnatlink,Building Executable Programs with GNAT +@anchor{gnat_ugn/building_executable_programs_with_gnat id47}@anchor{13e}@anchor{gnat_ugn/building_executable_programs_with_gnat using-the-gnu-make-utility}@anchor{21} +@section Using the GNU @cite{make} Utility -@end table +@geindex make (GNU) +@geindex GNU make + +This chapter offers some examples of makefiles that solve specific +problems. It does not explain how to write a makefile, nor does it try to replace the +@emph{gnatmake} utility (@ref{1d,,Building with gnatmake}). -@node The GNAT Make Program gnatmake -@chapter The GNAT Make Program @command{gnatmake} -@findex gnatmake +All the examples in this section are specific to the GNU version of +make. Although @emph{make} is a standard utility, and the basic language +is the same, these examples use some advanced features found only in +@cite{GNU make}. @menu -* Running gnatmake:: -* Switches for gnatmake:: -* Mode Switches for gnatmake:: -* Notes on the Command Line:: -* How gnatmake Works:: -* Examples of gnatmake Usage:: +* Using gnatmake in a Makefile:: +* Automatically Creating a List of Directories:: +* Generating the Command Line Switches:: +* Overcoming Command Line Length Limits:: + @end menu -@noindent -A typical development cycle when working on an Ada program consists of -the following steps: -@enumerate -@item -Edit some sources to fix bugs. +@node Using gnatmake in a Makefile,Automatically Creating a List of Directories,,Using the GNU make Utility +@anchor{gnat_ugn/building_executable_programs_with_gnat using-gnatmake-in-a-makefile}@anchor{13f}@anchor{gnat_ugn/building_executable_programs_with_gnat id48}@anchor{140} +@subsection Using gnatmake in a Makefile -@item -Add enhancements. -@item -Compile all sources affected. +@c index makefile (GNU make) -@item -Rebind and relink. +Complex project organizations can be handled in a very powerful way by +using GNU make combined with gnatmake. For instance, here is a Makefile +which allows you to build each subsystem of a big project into a separate +shared library. Such a makefile allows you to significantly reduce the link +time of very big applications while maintaining full coherence at +each step of the build process. -@item -Test. -@end enumerate +The list of dependencies are handled automatically by +@emph{gnatmake}. The Makefile is simply used to call gnatmake in each of +the appropriate directories. -@noindent -The third step can be tricky, because not only do the modified files -@cindex Dependency rules -have to be compiled, but any files depending on these files must also be -recompiled. The dependency rules in Ada can be quite complex, especially -in the presence of overloading, @code{use} clauses, generics and inlined -subprograms. +Note that you should also read the example on how to automatically +create the list of directories +(@ref{141,,Automatically Creating a List of Directories}) +which might help you in case your project has a lot of subdirectories. -@command{gnatmake} automatically takes care of the third and fourth steps -of this process. It determines which sources need to be compiled, -compiles them, and binds and links the resulting object files. +@example +## This Makefile is intended to be used with the following directory +## configuration: +## - The sources are split into a series of csc (computer software components) +## Each of these csc is put in its own directory. +## Their name are referenced by the directory names. +## They will be compiled into shared library (although this would also work +## with static libraries +## - The main program (and possibly other packages that do not belong to any +## csc is put in the top level directory (where the Makefile is). +## toplevel_dir __ first_csc (sources) __ lib (will contain the library) +## \\_ second_csc (sources) __ lib (will contain the library) +## \\_ ... +## Although this Makefile is build for shared library, it is easy to modify +## to build partial link objects instead (modify the lines with -shared and +## gnatlink below) +## +## With this makefile, you can change any file in the system or add any new +## file, and everything will be recompiled correctly (only the relevant shared +## objects will be recompiled, and the main program will be re-linked). -Unlike some other Ada make programs, the dependencies are always -accurately recomputed from the new sources. The source based approach of -the GNAT compilation model makes this possible. This means that if -changes to the source program cause corresponding changes in -dependencies, they will always be tracked exactly correctly by -@command{gnatmake}. +# The list of computer software component for your project. This might be +# generated automatically. +CSC_LIST=aa bb cc -@node Running gnatmake -@section Running @command{gnatmake} +# Name of the main program (no extension) +MAIN=main -@noindent -The usual form of the @command{gnatmake} command is +# If we need to build objects with -fPIC, uncomment the following line +#NEED_FPIC=-fPIC -@smallexample -@c $ gnatmake @ovar{switches} @var{file_name} -@c @ovar{file_names} @ovar{mode_switches} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatmake @r{[}@var{switches}@r{]} @var{file_name} - @r{[}@var{file_names}@r{]} @r{[}@var{mode_switches}@r{]} -@end smallexample +# The following variable should give the directory containing libgnat.so +# You can get this directory through 'gnatls -v'. This is usually the last +# directory in the Object_Path. +GLIB=... -@noindent -The only required argument is one @var{file_name}, which specifies -a compilation unit that is a main program. Several @var{file_names} can be -specified: this will result in several executables being built. -If @code{switches} are present, they can be placed before the first -@var{file_name}, between @var{file_names} or after the last @var{file_name}. -If @var{mode_switches} are present, they must always be placed after -the last @var{file_name} and all @code{switches}. +# The directories for the libraries +# (This macro expands the list of CSC to the list of shared libraries, you +# could simply use the expanded form: +# LIB_DIR=aa/lib/libaa.so bb/lib/libbb.so cc/lib/libcc.so +LIB_DIR=$@{foreach dir,$@{CSC_LIST@},$@{dir@}/lib/lib$@{dir@}.so@} -If you are using standard file extensions (@file{.adb} and @file{.ads}), then the -extension may be omitted from the @var{file_name} arguments. However, if -you are using non-standard extensions, then it is required that the -extension be given. A relative or absolute directory path can be -specified in a @var{file_name}, in which case, the input source file will -be searched for in the specified directory only. Otherwise, the input -source file will first be searched in the directory where -@command{gnatmake} was invoked and if it is not found, it will be search on -the source path of the compiler as described in -@ref{Search Paths and the Run-Time Library (RTL)}. +$@{MAIN@}: objects $@{LIB_DIR@} + gnatbind $@{MAIN@} $@{CSC_LIST:%=-aO%/lib@} -shared + gnatlink $@{MAIN@} $@{CSC_LIST:%=-l%@} -All @command{gnatmake} output (except when you specify -@option{-M}) is to -@file{stderr}. The output produced by the -@option{-M} switch is send to -@file{stdout}. +objects:: + # recompile the sources + gnatmake -c -i $@{MAIN@}.adb $@{NEED_FPIC@} $@{CSC_LIST:%=-I%@} -@node Switches for gnatmake -@section Switches for @command{gnatmake} +# Note: In a future version of GNAT, the following commands will be simplified +# by a new tool, gnatmlib +$@{LIB_DIR@}: + mkdir -p $@{dir $@@ @} + cd $@{dir $@@ @} && gcc -shared -o $@{notdir $@@ @} ../*.o -L$@{GLIB@} -lgnat + cd $@{dir $@@ @} && cp -f ../*.ali . -@noindent -You may specify any of the following switches to @command{gnatmake}: +# The dependencies for the modules +# Note that we have to force the expansion of *.o, since in some cases +# make won't be able to do it itself. +aa/lib/libaa.so: $@{wildcard aa/*.o@} +bb/lib/libbb.so: $@{wildcard bb/*.o@} +cc/lib/libcc.so: $@{wildcard cc/*.o@} -@table @option -@c !sort! +# Make sure all of the shared libraries are in the path before starting the +# program +run:: + LD_LIBRARY_PATH=`pwd`/aa/lib:`pwd`/bb/lib:`pwd`/cc/lib ./$@{MAIN@} -@item --version -@cindex @option{--version} @command{gnatmake} -Display Copyright and version, then exit disregarding all other options. +clean:: + $@{RM@} -rf $@{CSC_LIST:%=%/lib@} + $@{RM@} $@{CSC_LIST:%=%/*.ali@} + $@{RM@} $@{CSC_LIST:%=%/*.o@} + $@{RM@} *.o *.ali $@{MAIN@} +@end example -@item --help -@cindex @option{--help} @command{gnatmake} -If @option{--version} was not used, display usage, then exit disregarding -all other options. +@node Automatically Creating a List of Directories,Generating the Command Line Switches,Using gnatmake in a Makefile,Using the GNU make Utility +@anchor{gnat_ugn/building_executable_programs_with_gnat automatically-creating-a-list-of-directories}@anchor{141}@anchor{gnat_ugn/building_executable_programs_with_gnat id49}@anchor{142} +@subsection Automatically Creating a List of Directories -@item --GCC=@var{compiler_name} -@cindex @option{--GCC=compiler_name} (@command{gnatmake}) -Program used for compiling. The default is `@command{gcc}'. You need to use -quotes around @var{compiler_name} if @code{compiler_name} contains -spaces or other separator characters. As an example @option{--GCC="foo -x --y"} will instruct @command{gnatmake} to use @code{foo -x -y} as your -compiler. A limitation of this syntax is that the name and path name of -the executable itself must not include any embedded spaces. Note that -switch @option{-c} is always inserted after your command name. Thus in the -above example the compiler command that will be used by @command{gnatmake} -will be @code{foo -c -x -y}. If several @option{--GCC=compiler_name} are -used, only the last @var{compiler_name} is taken into account. However, -all the additional switches are also taken into account. Thus, -@option{--GCC="foo -x -y" --GCC="bar -z -t"} is equivalent to -@option{--GCC="bar -x -y -z -t"}. - -@item --GNATBIND=@var{binder_name} -@cindex @option{--GNATBIND=binder_name} (@command{gnatmake}) -Program used for binding. The default is `@code{gnatbind}'. You need to -use quotes around @var{binder_name} if @var{binder_name} contains spaces -or other separator characters. As an example @option{--GNATBIND="bar -x --y"} will instruct @command{gnatmake} to use @code{bar -x -y} as your -binder. Binder switches that are normally appended by @command{gnatmake} -to `@code{gnatbind}' are now appended to the end of @code{bar -x -y}. -A limitation of this syntax is that the name and path name of the executable -itself must not include any embedded spaces. -@item --GNATLINK=@var{linker_name} -@cindex @option{--GNATLINK=linker_name} (@command{gnatmake}) -Program used for linking. The default is `@command{gnatlink}'. You need to -use quotes around @var{linker_name} if @var{linker_name} contains spaces -or other separator characters. As an example @option{--GNATLINK="lan -x --y"} will instruct @command{gnatmake} to use @code{lan -x -y} as your -linker. Linker switches that are normally appended by @command{gnatmake} to -`@command{gnatlink}' are now appended to the end of @code{lan -x -y}. -A limitation of this syntax is that the name and path name of the executable -itself must not include any embedded spaces. +In most makefiles, you will have to specify a list of directories, and +store it in a variable. For small projects, it is often easier to +specify each of them by hand, since you then have full control over what +is the proper order for these directories, which ones should be +included. +However, in larger projects, which might involve hundreds of +subdirectories, it might be more convenient to generate this list +automatically. -@item --subdirs=subdir -Actual object directory of each project file is the subdirectory subdir of the -object directory specified or defaulted in the project file. +The example below presents two methods. The first one, although less +general, gives you more control over the list. It involves wildcard +characters, that are automatically expanded by @emph{make}. Its +shortcoming is that you need to explicitly specify some of the +organization of your project, such as for instance the directory tree +depth, whether some directories are found in a separate tree, etc. -@item --single-compile-per-obj-dir -Disallow simultaneous compilations in the same object directory when -project files are used. +The second method is the most general one. It requires an external +program, called @emph{find}, which is standard on all Unix systems. All +the directories found under a given root directory will be added to the +list. -@item --unchecked-shared-lib-imports -By default, shared library projects are not allowed to import static library -projects. When this switch is used on the command line, this restriction is -relaxed. +@example +# The examples below are based on the following directory hierarchy: +# All the directories can contain any number of files +# ROOT_DIRECTORY -> a -> aa -> aaa +# -> ab +# -> ac +# -> b -> ba -> baa +# -> bb +# -> bc +# This Makefile creates a variable called DIRS, that can be reused any time +# you need this list (see the other examples in this section) -@item --source-info=<source info file> -Specify a source info file. This switch is active only when project files -are used. If the source info file is specified as a relative path, then it is -relative to the object directory of the main project. If the source info file -does not exist, then after the Project Manager has successfully parsed and -processed the project files and found the sources, it creates the source info -file. If the source info file already exists and can be read successfully, -then the Project Manager will get all the needed information about the sources -from the source info file and will not look for them. This reduces the time -to process the project files, especially when looking for sources that take a -long time. If the source info file exists but cannot be parsed successfully, -the Project Manager will attempt to recreate it. If the Project Manager fails -to create the source info file, a message is issued, but gnatmake does not -fail. @command{gnatmake} "trusts" the source info file. This means that -if the source files have changed (addition, deletion, moving to a different -source directory), then the source info file need to be deleted and recreated. +# The root of your project's directory hierarchy +ROOT_DIRECTORY=. -@item --create-map-file -When linking an executable, create a map file. The name of the map file -has the same name as the executable with extension ".map". +#### +# First method: specify explicitly the list of directories +# This allows you to specify any subset of all the directories you need. +#### -@item --create-map-file=mapfile -When linking an executable, create a map file. The name of the map file is -"mapfile". +DIRS := a/aa/ a/ab/ b/ba/ +#### +# Second method: use wildcards +# Note that the argument(s) to wildcard below should end with a '/'. +# Since wildcards also return file names, we have to filter them out +# to avoid duplicate directory names. +# We thus use make's `dir` and `sort` functions. +# It sets DIRs to the following value (note that the directories aaa and baa +# are not given, unless you change the arguments to wildcard). +# DIRS= ./a/a/ ./b/ ./a/aa/ ./a/ab/ ./a/ac/ ./b/ba/ ./b/bb/ ./b/bc/ +#### -@item -a -@cindex @option{-a} (@command{gnatmake}) -Consider all files in the make process, even the GNAT internal system -files (for example, the predefined Ada library files), as well as any -locked files. Locked files are files whose ALI file is write-protected. -By default, -@command{gnatmake} does not check these files, -because the assumption is that the GNAT internal files are properly up -to date, and also that any write protected ALI files have been properly -installed. Note that if there is an installation problem, such that one -of these files is not up to date, it will be properly caught by the -binder. -You may have to specify this switch if you are working on GNAT -itself. The switch @option{-a} is also useful -in conjunction with @option{-f} -if you need to recompile an entire application, -including run-time files, using special configuration pragmas, -such as a @code{Normalize_Scalars} pragma. +DIRS := $@{sort $@{dir $@{wildcard $@{ROOT_DIRECTORY@}/*/ + $@{ROOT_DIRECTORY@}/*/*/@}@}@} -By default -@code{gnatmake -a} compiles all GNAT -internal files with -@code{gcc -c -gnatpg} rather than @code{gcc -c}. +#### +# Third method: use an external program +# This command is much faster if run on local disks, avoiding NFS slowdowns. +# This is the most complete command: it sets DIRs to the following value: +# DIRS= ./a ./a/aa ./a/aa/aaa ./a/ab ./a/ac ./b ./b/ba ./b/ba/baa ./b/bb ./b/bc +#### -@item -b -@cindex @option{-b} (@command{gnatmake}) -Bind only. Can be combined with @option{-c} to do -compilation and binding, but no link. -Can be combined with @option{-l} -to do binding and linking. When not combined with -@option{-c} -all the units in the closure of the main program must have been previously -compiled and must be up to date. The root unit specified by @var{file_name} -may be given without extension, with the source extension or, if no GNAT -Project File is specified, with the ALI file extension. +DIRS := $@{shell find $@{ROOT_DIRECTORY@} -type d -print@} +@end example -@item -c -@cindex @option{-c} (@command{gnatmake}) -Compile only. Do not perform binding, except when @option{-b} -is also specified. Do not perform linking, except if both -@option{-b} and -@option{-l} are also specified. -If the root unit specified by @var{file_name} is not a main unit, this is the -default. Otherwise @command{gnatmake} will attempt binding and linking -unless all objects are up to date and the executable is more recent than -the objects. +@node Generating the Command Line Switches,Overcoming Command Line Length Limits,Automatically Creating a List of Directories,Using the GNU make Utility +@anchor{gnat_ugn/building_executable_programs_with_gnat id50}@anchor{143}@anchor{gnat_ugn/building_executable_programs_with_gnat generating-the-command-line-switches}@anchor{144} +@subsection Generating the Command Line Switches -@item -C -@cindex @option{-C} (@command{gnatmake}) -Use a temporary mapping file. A mapping file is a way to communicate -to the compiler two mappings: from unit names to file names (without -any directory information) and from file names to path names (with -full directory information). A mapping file can make the compiler's -file searches faster, especially if there are many source directories, -or the sources are read over a slow network connection. If -@option{-P} is used, a mapping file is always used, so -@option{-C} is unnecessary; in this case the mapping file -is initially populated based on the project file. If -@option{-C} is used without -@option{-P}, -the mapping file is initially empty. Each invocation of the compiler -will add any newly accessed sources to the mapping file. -@item -C=@var{file} -@cindex @option{-C=} (@command{gnatmake}) -Use a specific mapping file. The file, specified as a path name (absolute or -relative) by this switch, should already exist, otherwise the switch is -ineffective. The specified mapping file will be communicated to the compiler. -This switch is not compatible with a project file -(-P@var{file}) or with multiple compiling processes -(-jnnn, when nnn is greater than 1). +Once you have created the list of directories as explained in the +previous section (@ref{141,,Automatically Creating a List of Directories}), +you can easily generate the command line arguments to pass to gnatmake. -@item -d -@cindex @option{-d} (@command{gnatmake}) -Display progress for each source, up to date or not, as a single line +For the sake of completeness, this example assumes that the source path +is not the same as the object path, and that you have two separate lists +of directories. -@smallexample -completed x out of y (zz%) -@end smallexample +@example +# see "Automatically creating a list of directories" to create +# these variables +SOURCE_DIRS= +OBJECT_DIRS= -If the file needs to be compiled this is displayed after the invocation of -the compiler. These lines are displayed even in quiet output mode. +GNATMAKE_SWITCHES := $@{patsubst %,-aI%,$@{SOURCE_DIRS@}@} +GNATMAKE_SWITCHES += $@{patsubst %,-aO%,$@{OBJECT_DIRS@}@} -@item -D @var{dir} -@cindex @option{-D} (@command{gnatmake}) -Put all object files and ALI file in directory @var{dir}. -If the @option{-D} switch is not used, all object files -and ALI files go in the current working directory. +all: + gnatmake $@{GNATMAKE_SWITCHES@} main_unit +@end example -This switch cannot be used when using a project file. +@node Overcoming Command Line Length Limits,,Generating the Command Line Switches,Using the GNU make Utility +@anchor{gnat_ugn/building_executable_programs_with_gnat overcoming-command-line-length-limits}@anchor{145}@anchor{gnat_ugn/building_executable_programs_with_gnat id51}@anchor{146} +@subsection Overcoming Command Line Length Limits -@item -eInnn -@cindex @option{-eI} (@command{gnatmake}) -Indicates that the main source is a multi-unit source and the rank of the unit -in the source file is nnn. nnn needs to be a positive number and a valid -index in the source. This switch cannot be used when @command{gnatmake} is -invoked for several mains. -@item -eL -@cindex @option{-eL} (@command{gnatmake}) -@cindex symbolic links -Follow all symbolic links when processing project files. -This should be used if your project uses symbolic links for files or -directories, but is not needed in other cases. +One problem that might be encountered on big projects is that many +operating systems limit the length of the command line. It is thus hard to give +gnatmake the list of source and object directories. -@cindex naming scheme -This also assumes that no directory matches the naming scheme for files (for -instance that you do not have a directory called "sources.ads" when using the -default GNAT naming scheme). +This example shows how you can set up environment variables, which will +make @emph{gnatmake} behave exactly as if the directories had been +specified on the command line, but have a much higher length limit (or +even none on most systems). -When you do not have to use this switch (i.e.@: by default), gnatmake is able to -save a lot of system calls (several per source file and object file), which -can result in a significant speed up to load and manipulate a project file, -especially when using source files from a remote system. +It assumes that you have created a list of directories in your Makefile, +using one of the methods presented in +@ref{141,,Automatically Creating a List of Directories}. +For the sake of completeness, we assume that the object +path (where the ALI files are found) is different from the sources patch. +Note a small trick in the Makefile below: for efficiency reasons, we +create two temporary variables (SOURCE_LIST and OBJECT_LIST), that are +expanded immediately by @cite{make}. This way we overcome the standard +make behavior which is to expand the variables only when they are +actually used. -@item -eS -@cindex @option{-eS} (@command{gnatmake}) -Output the commands for the compiler, the binder and the linker -on standard output, -instead of standard error. +On Windows, if you are using the standard Windows command shell, you must +replace colons with semicolons in the assignments to these variables. -@item -f -@cindex @option{-f} (@command{gnatmake}) -Force recompilations. Recompile all sources, even though some object -files may be up to date, but don't recompile predefined or GNAT internal -files or locked files (files with a write-protected ALI file), -unless the @option{-a} switch is also specified. +@example +# In this example, we create both ADA_INCLUDE_PATH and ADA_OBJECTS_PATH. +# This is the same thing as putting the -I arguments on the command line. +# (the equivalent of using -aI on the command line would be to define +# only ADA_INCLUDE_PATH, the equivalent of -aO is ADA_OBJECTS_PATH). +# You can of course have different values for these variables. +# +# Note also that we need to keep the previous values of these variables, since +# they might have been set before running 'make' to specify where the GNAT +# library is installed. -@item -F -@cindex @option{-F} (@command{gnatmake}) -When using project files, if some errors or warnings are detected during -parsing and verbose mode is not in effect (no use of switch --v), then error lines start with the full path name of the project -file, rather than its simple file name. +# see "Automatically creating a list of directories" to create these +# variables +SOURCE_DIRS= +OBJECT_DIRS= -@item -g -@cindex @option{-g} (@command{gnatmake}) -Enable debugging. This switch is simply passed to the compiler and to the -linker. +empty:= +space:=$@{empty@} $@{empty@} +SOURCE_LIST := $@{subst $@{space@},:,$@{SOURCE_DIRS@}@} +OBJECT_LIST := $@{subst $@{space@},:,$@{OBJECT_DIRS@}@} +ADA_INCLUDE_PATH += $@{SOURCE_LIST@} +ADA_OBJECTS_PATH += $@{OBJECT_LIST@} +export ADA_INCLUDE_PATH +export ADA_OBJECTS_PATH -@item -i -@cindex @option{-i} (@command{gnatmake}) -In normal mode, @command{gnatmake} compiles all object files and ALI files -into the current directory. If the @option{-i} switch is used, -then instead object files and ALI files that already exist are overwritten -in place. This means that once a large project is organized into separate -directories in the desired manner, then @command{gnatmake} will automatically -maintain and update this organization. If no ALI files are found on the -Ada object path (@ref{Search Paths and the Run-Time Library (RTL)}), -the new object and ALI files are created in the -directory containing the source being compiled. If another organization -is desired, where objects and sources are kept in different directories, -a useful technique is to create dummy ALI files in the desired directories. -When detecting such a dummy file, @command{gnatmake} will be forced to -recompile the corresponding source file, and it will be put the resulting -object and ALI files in the directory where it found the dummy file. +all: + gnatmake main_unit +@end example -@item -j@var{n} -@cindex @option{-j} (@command{gnatmake}) -@cindex Parallel make -Use @var{n} processes to carry out the (re)compilations. On a multiprocessor -machine compilations will occur in parallel. If @var{n} is 0, then the -maximum number of parallel compilations is the number of core processors -on the platform. In the event of compilation errors, messages from various -compilations might get interspersed (but @command{gnatmake} will give you the -full ordered list of failing compiles at the end). If this is problematic, -rerun the make process with n set to 1 to get a clean list of messages. +@c -- Example: A |withing| unit has a |with| clause, it |withs| a |withed| unit -@item -k -@cindex @option{-k} (@command{gnatmake}) -Keep going. Continue as much as possible after a compilation error. To -ease the programmer's task in case of compilation errors, the list of -sources for which the compile fails is given when @command{gnatmake} -terminates. +@node GNAT Project Manager,Tools Supporting Project Files,Building Executable Programs with GNAT,Top +@anchor{gnat_ugn/gnat_project_manager doc}@anchor{147}@anchor{gnat_ugn/gnat_project_manager gnat-project-manager}@anchor{b}@anchor{gnat_ugn/gnat_project_manager id1}@anchor{148} +@chapter GNAT Project Manager -If @command{gnatmake} is invoked with several @file{file_names} and with this -switch, if there are compilation errors when building an executable, -@command{gnatmake} will not attempt to build the following executables. -@item -l -@cindex @option{-l} (@command{gnatmake}) -Link only. Can be combined with @option{-b} to binding -and linking. Linking will not be performed if combined with -@option{-c} -but not with @option{-b}. -When not combined with @option{-b} -all the units in the closure of the main program must have been previously -compiled and must be up to date, and the main program needs to have been bound. -The root unit specified by @var{file_name} -may be given without extension, with the source extension or, if no GNAT -Project File is specified, with the ALI file extension. +@menu +* Introduction:: +* Building With Projects:: +* Organizing Projects into Subsystems:: +* Scenarios in Projects:: +* Library Projects:: +* Project Extension:: +* Aggregate Projects:: +* Aggregate Library Projects:: +* Project File Reference:: -@item -m -@cindex @option{-m} (@command{gnatmake}) -Specify that the minimum necessary amount of recompilations -be performed. In this mode @command{gnatmake} ignores time -stamp differences when the only -modifications to a source file consist in adding/removing comments, -empty lines, spaces or tabs. This means that if you have changed the -comments in a source file or have simply reformatted it, using this -switch will tell @command{gnatmake} not to recompile files that depend on it -(provided other sources on which these files depend have undergone no -semantic modifications). Note that the debugging information may be -out of date with respect to the sources if the @option{-m} switch causes -a compilation to be switched, so the use of this switch represents a -trade-off between compilation time and accurate debugging information. +@end menu -@item -M -@cindex Dependencies, producing list -@cindex @option{-M} (@command{gnatmake}) -Check if all objects are up to date. If they are, output the object -dependences to @file{stdout} in a form that can be directly exploited in -a @file{Makefile}. By default, each source file is prefixed with its -(relative or absolute) directory name. This name is whatever you -specified in the various @option{-aI} -and @option{-I} switches. If you use -@code{gnatmake -M} -@option{-q} -(see below), only the source file names, -without relative paths, are output. If you just specify the -@option{-M} -switch, dependencies of the GNAT internal system files are omitted. This -is typically what you want. If you also specify -the @option{-a} switch, -dependencies of the GNAT internal files are also listed. Note that -dependencies of the objects in external Ada libraries (see switch -@option{-aL}@var{dir} in the following list) -are never reported. +@node Introduction,Building With Projects,,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager introduction}@anchor{149}@anchor{gnat_ugn/gnat_project_manager gnat-project-manager-introduction}@anchor{14a} +@section Introduction -@item -n -@cindex @option{-n} (@command{gnatmake}) -Don't compile, bind, or link. Checks if all objects are up to date. -If they are not, the full name of the first file that needs to be -recompiled is printed. -Repeated use of this option, followed by compiling the indicated source -file, will eventually result in recompiling all required units. -@item -o @var{exec_name} -@cindex @option{-o} (@command{gnatmake}) -Output executable name. The name of the final executable program will be -@var{exec_name}. If the @option{-o} switch is omitted the default -name for the executable will be the name of the input file in appropriate form -for an executable file on the host system. +This chapter describes GNAT's @emph{Project Manager}, a facility that allows +you to manage complex builds involving a number of source files, directories, +and options for different system configurations. In particular, +project files allow you to specify: -This switch cannot be used when invoking @command{gnatmake} with several -@file{file_names}. -@item -p or --create-missing-dirs -@cindex @option{-p} (@command{gnatmake}) -When using project files (-P@var{project}), create -automatically missing object directories, library directories and exec -directories. +@itemize * -@item -P@var{project} -@cindex @option{-P} (@command{gnatmake}) -Use project file @var{project}. Only one such switch can be used. -@xref{gnatmake and Project Files}. +@item +The directory or set of directories containing the source files, and/or the +names of the specific source files themselves -@item -q -@cindex @option{-q} (@command{gnatmake}) -Quiet. When this flag is not set, the commands carried out by -@command{gnatmake} are displayed. +@item +The directory in which the compiler's output +(@code{ALI} files, object files, tree files, etc.) is to be placed -@item -s -@cindex @option{-s} (@command{gnatmake}) -Recompile if compiler switches have changed since last compilation. -All compiler switches but -I and -o are taken into account in the -following way: -orders between different ``first letter'' switches are ignored, but -orders between same switches are taken into account. For example, -@option{-O -O2} is different than @option{-O2 -O}, but @option{-g -O} -is equivalent to @option{-O -g}. +@item +The directory in which the executable programs are to be placed -This switch is recommended when Integrated Preprocessing is used. +@item +Switch settings for any of the project-enabled tools; +you can apply these settings either globally or to individual compilation units. -@item -u -@cindex @option{-u} (@command{gnatmake}) -Unique. Recompile at most the main files. It implies -c. Combined with --f, it is equivalent to calling the compiler directly. Note that using --u with a project file and no main has a special meaning -(@pxref{Project Files and Main Subprograms}). +@item +The source files containing the main subprogram(s) to be built -@item -U -@cindex @option{-U} (@command{gnatmake}) -When used without a project file or with one or several mains on the command -line, is equivalent to -u. When used with a project file and no main -on the command line, all sources of all project files are checked and compiled -if not up to date, and libraries are rebuilt, if necessary. +@item +The source programming language(s) -@item -v -@cindex @option{-v} (@command{gnatmake}) -Verbose. Display the reason for all recompilations @command{gnatmake} -decides are necessary, with the highest verbosity level. +@item +Source file naming conventions; you can specify these either globally or for +individual compilation units (see @ref{14b,,Naming Schemes}). -@item -vl -@cindex @option{-vl} (@command{gnatmake}) -Verbosity level Low. Display fewer lines than in verbosity Medium. +@item +Change any of the above settings depending on external values, thus enabling +the reuse of the projects in various @strong{scenarios} (see @ref{14c,,Scenarios in Projects}). -@item -vm -@cindex @option{-vm} (@command{gnatmake}) -Verbosity level Medium. Potentially display fewer lines than in verbosity High. +@item +Automatically build libraries as part of the build process +(see @ref{8a,,Library Projects}). +@end itemize -@item -vh -@cindex @option{-vm} (@command{gnatmake}) -Verbosity level High. Equivalent to -v. +Project files are written in a syntax close to that of Ada, using familiar +notions such as packages, context clauses, declarations, default values, +assignments, and inheritance (see @ref{14d,,Project File Reference}). -@item -vP@emph{x} -Indicate the verbosity of the parsing of GNAT project files. -@xref{Switches Related to Project Files}. +Project files can be built hierarchically from other project files, simplifying +complex system integration and project reuse (see @ref{14e,,Organizing Projects into Subsystems}). -@item -x -@cindex @option{-x} (@command{gnatmake}) -Indicate that sources that are not part of any Project File may be compiled. -Normally, when using Project Files, only sources that are part of a Project -File may be compile. When this switch is used, a source outside of all Project -Files may be compiled. The ALI file and the object file will be put in the -object directory of the main Project. The compilation switches used will only -be those specified on the command line. Even when -@option{-x} is used, mains specified on the -command line need to be sources of a project file. -@item -X@var{name=value} -Indicate that external variable @var{name} has the value @var{value}. -The Project Manager will use this value for occurrences of -@code{external(name)} when parsing the project file. -@xref{Switches Related to Project Files}. +@itemize * -@item -z -@cindex @option{-z} (@command{gnatmake}) -No main subprogram. Bind and link the program even if the unit name -given on the command line is a package name. The resulting executable -will execute the elaboration routines of the package and its closure, -then the finalization routines. +@item +One project can import other projects containing needed source files. +More generally, the Project Manager lets you structure large development +efforts into hierarchical subsystems, where build decisions are delegated +to the subsystem level, and thus different compilation environments +(switch settings) used for different subsystems. + +@item +You can organize GNAT projects in a hierarchy: a child project +can extend a parent project, inheriting the parent's source files and +optionally overriding any of them with alternative versions +(see @ref{14f,,Project Extension}). +@end itemize + +Several tools support project files, generally in addition to specifying +the information on the command line itself). They share common switches +to control the loading of the project (in particular +@code{-P@emph{projectfile}} and +@code{-X@emph{vbl}=@emph{value}}). + +The Project Manager supports a wide range of development strategies, +for systems of all sizes. Here are some typical practices that are +easily handled: + + +@itemize * + +@item +Using a common set of source files and generating object files in different +directories via different switch settings. It can be used for instance, for +generating separate sets of object files for debugging and for production. + +@item +Using a mostly-shared set of source files with different versions of +some units or subunits. It can be used for instance, for grouping and hiding +all OS dependencies in a small number of implementation units. +@end itemize + +Project files can be used to achieve some of the effects of a source +versioning system (for example, defining separate projects for +the different sets of sources that comprise different releases) but the +Project Manager is independent of any source configuration management tool +that might be used by the developers. + +The various sections below introduce the different concepts related to +projects. Each section starts with examples and use cases, and then goes into +the details of related project file capabilities. + +@node Building With Projects,Organizing Projects into Subsystems,Introduction,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager building-with-projects}@anchor{150}@anchor{gnat_ugn/gnat_project_manager id2}@anchor{151} +@section Building With Projects + + +In its simplest form, a unique project is used to build a single executable. +This section concentrates on such a simple setup. Later sections will extend +this basic model to more complex setups. + +The following concepts are the foundation of project files, and will be further +detailed later in this documentation. They are summarized here as a reference. -@end table @table @asis -@item @command{gcc} @asis{switches} -Any uppercase or multi-character switch that is not a @command{gnatmake} switch -is passed to @command{gcc} (e.g.@: @option{-O}, @option{-gnato,} etc.) + +@item @strong{Project file}: + +A text file using an Ada-like syntax, generally using the @code{.gpr} +extension. It defines build-related characteristics of an application. +The characteristics include the list of sources, the location of those +sources, the location for the generated object files, the name of +the main program, and the options for the various tools involved in the +build process. + +@item @strong{Project attribute}: + +A specific project characteristic is defined by an attribute clause. Its +value is a string or a sequence of strings. All settings in a project +are defined through a list of predefined attributes with precise +semantics. See @ref{152,,Attributes}. + +@item @strong{Package in a project}: + +Global attributes are defined at the top level of a project. +Attributes affecting specific tools are grouped in a +package whose name is related to tool's function. The most common +packages are @cite{Builder}, @cite{Compiler}, @cite{Binder}, +and @cite{Linker}. See @ref{153,,Packages}. + +@item @strong{Project variables}: + +In addition to attributes, a project can use variables to store intermediate +values and avoid duplication in complex expressions. It can be initialized +with a value coming from the environment. +A frequent use of variables is to define scenarios. +See @ref{154,,External Values}, @ref{14c,,Scenarios in Projects}, and @ref{155,,Variables}. + +@item @strong{Source files} and @strong{source directories}: + +A source file is associated with a language through a naming convention. For +instance, @cite{foo.c} is typically the name of a C source file; +@cite{bar.ads} or @cite{bar.1.ada} are two common naming conventions for a +file containing an Ada spec. A compilation unit is often composed of a main +source file and potentially several auxiliary ones, such as header files in C. +The naming conventions can be user defined @ref{14b,,Naming Schemes}, and will +drive the builder to call the appropriate compiler for the given source file. +Source files are searched for in the source directories associated with the +project through the @strong{Source_Dirs} attribute. By default, all the files (in +these source directories) following the naming conventions associated with the +declared languages are considered to be part of the project. It is also +possible to limit the list of source files using the @strong{Source_Files} or +@strong{Source_List_File} attributes. Note that those last two attributes only +accept basenames with no directory information. + +@item @strong{Object files} and @strong{object directory}: + +An object file is an intermediate file produced by the compiler from a +compilation unit. It is used by post-compilation tools to produce +final executables or libraries. Object files produced in the context of +a given project are stored in a single directory that can be specified by the +@strong{Object_Dir} attribute. In order to store objects in +two or more object directories, the system must be split into +distinct subsystems with their own project file. @end table -@noindent -Source and library search path switches: +The following subsections introduce gradually all the attributes of interest +for simple build needs. Here is the simple setup that will be used in the +following examples. + +The Ada source files @code{pack.ads}, @code{pack.adb}, and @code{proc.adb} are in +the @code{common/} directory. The file @code{proc.adb} contains an Ada main +subprogram @cite{Proc} that @emph{with}s package @cite{Pack}. We want to compile +these source files with the switch +@emph{-O2}, and put the resulting files in +the directory @code{obj/}. + +@example +common/ + pack.ads + pack.adb + proc.adb +common/obj/ + proc.ali, proc.o pack.ali, pack.o +@end example + +Our project is to be called @emph{Build}. The name of the +file is the name of the project (case-insensitive) with the +@code{.gpr} extension, therefore the project file name is @code{build.gpr}. This +is not mandatory, but a warning is issued when this convention is not followed. + +This is a very simple example, and as stated above, a single project +file is enough for it. We will thus create a new file, that for now +should contain the following code: + +@example +project Build is +end Build; +@end example -@table @option -@c !sort! -@item -aI@var{dir} -@cindex @option{-aI} (@command{gnatmake}) -When looking for source files also look in directory @var{dir}. -The order in which source files search is undertaken is -described in @ref{Search Paths and the Run-Time Library (RTL)}. - -@item -aL@var{dir} -@cindex @option{-aL} (@command{gnatmake}) -Consider @var{dir} as being an externally provided Ada library. -Instructs @command{gnatmake} to skip compilation units whose @file{.ALI} -files have been located in directory @var{dir}. This allows you to have -missing bodies for the units in @var{dir} and to ignore out of date bodies -for the same units. You still need to specify -the location of the specs for these units by using the switches -@option{-aI@var{dir}} -or @option{-I@var{dir}}. -Note: this switch is provided for compatibility with previous versions -of @command{gnatmake}. The easier method of causing standard libraries -to be excluded from consideration is to write-protect the corresponding -ALI files. +@menu +* Source Files and Directories:: +* Duplicate Sources in Projects:: +* Object and Exec Directory:: +* Main Subprograms:: +* Tools Options in Project Files:: +* Compiling with Project Files:: +* Executable File Names:: +* Avoid Duplication With Variables:: +* Naming Schemes:: +* Installation:: +* Distributed support:: -@item -aO@var{dir} -@cindex @option{-aO} (@command{gnatmake}) -When searching for library and object files, look in directory -@var{dir}. The order in which library files are searched is described in -@ref{Search Paths for gnatbind}. - -@item -A@var{dir} -@cindex Search paths, for @command{gnatmake} -@cindex @option{-A} (@command{gnatmake}) -Equivalent to @option{-aL@var{dir} --aI@var{dir}}. - -@item -I@var{dir} -@cindex @option{-I} (@command{gnatmake}) -Equivalent to @option{-aO@var{dir} --aI@var{dir}}. - -@item -I- -@cindex @option{-I-} (@command{gnatmake}) -@cindex Source files, suppressing search -Do not look for source files in the directory containing the source -file named in the command line. -Do not look for ALI or object files in the directory -where @command{gnatmake} was invoked. +@end menu -@item -L@var{dir} -@cindex @option{-L} (@command{gnatmake}) -@cindex Linker libraries -Add directory @var{dir} to the list of directories in which the linker -will search for libraries. This is equivalent to -@option{-largs -L}@var{dir}. -Furthermore, under Windows, the sources pointed to by the libraries path -set in the registry are not searched for. +@node Source Files and Directories,Duplicate Sources in Projects,,Building With Projects +@anchor{gnat_ugn/gnat_project_manager id3}@anchor{156}@anchor{gnat_ugn/gnat_project_manager source-files-and-directories}@anchor{157} +@subsection Source Files and Directories -@item -nostdinc -@cindex @option{-nostdinc} (@command{gnatmake}) -Do not look for source files in the system default directory. -@item -nostdlib -@cindex @option{-nostdlib} (@command{gnatmake}) -Do not look for library files in the system default directory. +When you create a new project, the first thing to describe is how to find the +corresponding source files. These are the only settings that are needed by all +the tools that will use this project (builder, compiler, binder and linker for +the compilation, IDEs to edit the source files,...). -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gnatmake}) -Specifies the default location of the runtime library. GNAT looks for the -runtime -in the following directories, and stops as soon as a valid runtime is found -(@file{adainclude} or @file{ada_source_path}, and @file{adalib} or -@file{ada_object_path} present): +@geindex Source directories (GNAT Project Manager) + +The first step is to declare the source directories, which are the directories +to be searched to find source files. In the case of the example, +the @code{common} directory is the only source directory. + +@geindex Source_Dirs (GNAT Project Manager) -@itemize @bullet -@item <current directory>/$rts_path +There are several ways of defining source directories: -@item <default-search-dir>/$rts_path -@item <default-search-dir>/rts-$rts_path +@itemize * + +@item +When the attribute @strong{Source_Dirs} is not used, a project contains a +single source directory which is the one where the project file itself +resides. In our example, if @code{build.gpr} is placed in the @code{common} +directory, the project has the needed implicit source directory. + +@item +The attribute @strong{Source_Dirs} can be set to a list of path names, one +for each of the source directories. Such paths can either be absolute +names (for instance @code{"/usr/local/common/"} on UNIX), or relative to the +directory in which the project file resides (for instance "." if +@code{build.gpr} is inside @code{common/}, or "common" if it is one level up). +Each of the source directories must exist and be readable. + +@geindex portability of path names (GNAT Project Manager) + +The syntax for directories is platform specific. For portability, however, +the project manager will always properly translate UNIX-like path names to +the native format of the specific platform. For instance, when the same +project file is to be used both on Unix and Windows, "/" should be used as +the directory separator rather than "\". + +@item +The attribute @strong{Source_Dirs} can automatically include subdirectories +using a special syntax inspired by some UNIX shells. If any of the paths in +the list ends with "@code{**}", then that path and all its subdirectories +(recursively) are included in the list of source directories. For instance, +@code{**} and @code{./**} represent the complete directory tree rooted at +the directory in which the project file resides. + +@geindex Source directories (GNAT Project Manager) + +@geindex Excluded_Source_Dirs (GNAT Project Manager) + +When using that construct, it can sometimes be convenient to also use the +attribute @strong{Excluded_Source_Dirs}, which is also a list of paths. Each entry +specifies a directory whose immediate content, not including subdirs, is to +be excluded. It is also possible to exclude a complete directory subtree +using the "**" notation. + +@geindex Ignore_Source_Sub_Dirs (GNAT Project Manager) + +It is often desirable to remove, from the source directories, directory +subtrees rooted at some subdirectories. An example is the subdirectories +created by a Version Control System such as Subversion that creates directory +subtrees rooted at subdirectories ".svn". To do that, attribute +@strong{Ignore_Source_Sub_Dirs} can be used. It specifies the list of simple +file names for the roots of these undesirable directory subtrees. + +@c code-block: ada-project +@c +@c for Source_Dirs use ("./**"); +@c for Ignore_Source_Sub_Dirs use (".svn"); @end itemize -@noindent -The selected path is handled like a normal RTS path. +When applied to the simple example, and because we generally prefer to have +the project file at the toplevel directory rather than mixed with the sources, +we will create the following file + +@c code-block: ada-project +@c +@c build.gpr +@c project Build is +@c for Source_Dirs use ("common"); -- <<<< +@c end Build; + +Once source directories have been specified, one may need to indicate +source files of interest. By default, all source files present in the source +directories are considered by the project manager. When this is not desired, +it is possible to specify the list of sources to consider explicitly. +In such a case, only source file base names are indicated and not +their absolute or relative path names. The project manager is in charge of +locating the specified source files in the specified source directories. + + +@itemize * + +@item +By default, the project manager searches for all source files of all +specified languages in all the source directories. + +Since the project manager was initially developed for Ada environments, the +default language is usually Ada and the above project file is complete: it +defines without ambiguity the sources composing the project: that is to say, +all the sources in subdirectory "common" for the default language (Ada) using +the default naming convention. + +@geindex Languages (GNAT Project Manager) + +However, when compiling a multi-language application, or a pure C +application, the project manager must be told which languages are of +interest, which is done by setting the @strong{Languages} attribute to a list of +strings, each of which is the name of a language. Tools like +@emph{gnatmake} only know about Ada, while other tools like +@emph{gprbuild} know about many more languages such as C, C++, Fortran, +assembly and others can be added dynamically. + +@geindex Naming scheme (GNAT Project Manager) + +Even when using only Ada, the default naming might not be suitable. Indeed, +how does the project manager recognizes an "Ada file" from any other +file? Project files can describe the naming scheme used for source files, +and override the default (see @ref{14b,,Naming Schemes}). The default is the +standard GNAT extension (@code{.adb} for bodies and @code{.ads} for +specs), which is what is used in our example, explaining why no naming scheme +is explicitly specified. +See @ref{14b,,Naming Schemes}. + +@geindex Source_Files (GNAT Project Manager) + +@item +@cite{Source_Files}. +In some cases, source directories might contain files that should not be +included in a project. One can specify the explicit list of file names to +be considered through the @strong{Source_Files} attribute. +When this attribute is defined, instead of looking at every file in the +source directories, the project manager takes only those names into +consideration reports errors if they cannot be found in the source +directories or does not correspond to the naming scheme. + +@item +For various reasons, it is sometimes useful to have a project with no +sources (most of the time because the attributes defined in the project +file will be reused in other projects, as explained in +@ref{14e,,Organizing Projects into Subsystems}. To do this, the attribute +@emph{Source_Files} is set to the empty list, i.e. @cite{()}. Alternatively, +@emph{Source_Dirs} can be set to the empty list, with the same +result. + +@geindex Source_List_File (GNAT Project Manager) + +@item +@cite{Source_List_File}. +If there is a great number of files, it might be more convenient to use +the attribute @strong{Source_List_File}, which specifies the full path of a file. +This file must contain a list of source file names (one per line, no +directory information) that are searched as if they had been defined +through @emph{Source_Files}. Such a file can easily be created through +external tools. + +A warning is issued if both attributes @cite{Source_Files} and +@cite{Source_List_File} are given explicit values. In this case, the +attribute @cite{Source_Files} prevails. + +@geindex Excluded_Source_Files (GNAT Project Manager) + +@geindex Locally_Removed_Files (GNAT Project Manager) + +@geindex Excluded_Source_List_File (GNAT Project Manager) + +@item +@cite{Excluded_Source_Files}. +Specifying an explicit list of files is not always convenient.It might be +more convenient to use the default search rules with specific exceptions. +This can be done thanks to the attribute @strong{Excluded_Source_Files} +(or its synonym @strong{Locally_Removed_Files}). +Its value is the list of file names that should not be taken into account. +This attribute is often used when extending a project, +see @ref{14f,,Project Extension}. A similar attribute +@strong{Excluded_Source_List_File} plays the same +role but takes the name of file containing file names similarly to +@cite{Source_List_File}. +@end itemize -@end table +In most simple cases, such as the above example, the default source file search +behavior provides the expected result, and we do not need to add anything after +setting @cite{Source_Dirs}. The project manager automatically finds +@code{pack.ads}, @code{pack.adb}, and @code{proc.adb} as source files of the +project. + +Note that by default a warning is issued when a project has no sources attached +to it and this is not explicitly indicated in the project file. + +@node Duplicate Sources in Projects,Object and Exec Directory,Source Files and Directories,Building With Projects +@anchor{gnat_ugn/gnat_project_manager duplicate-sources-in-projects}@anchor{158}@anchor{gnat_ugn/gnat_project_manager id4}@anchor{159} +@subsection Duplicate Sources in Projects + + +If the order of the source directories is known statically, that is if +@cite{"/**"} is not used in the string list @cite{Source_Dirs}, then there may +be several files with the same name sitting in different directories of the +project. In this case, only the file in the first directory is considered as a +source of the project and the others are hidden. If @cite{"/**"} is used in the +string list @cite{Source_Dirs}, it is an error to have several files with the +same name in the same directory @cite{"/**"} subtree, since there would be an +ambiguity as to which one should be used. However, two files with the same name +may exist in two single directories or directory subtrees. In this case, the +one in the first directory or directory subtree is a source of the project. + +If there are two sources in different directories of the same @cite{"/**"} +subtree, one way to resolve the problem is to exclude the directory of the +file that should not be used as a source of the project. + +@node Object and Exec Directory,Main Subprograms,Duplicate Sources in Projects,Building With Projects +@anchor{gnat_ugn/gnat_project_manager object-and-exec-directory}@anchor{15a}@anchor{gnat_ugn/gnat_project_manager id5}@anchor{15b} +@subsection Object and Exec Directory + + +The next step when writing a project is to indicate where the compiler should +put the object files. In fact, the compiler and other tools might create +several different kind of files (for GNAT, there is the object file and the ALI +file for instance). One of the important concepts in projects is that most +tools may consider source directories as read-only and do not attempt to create +new or temporary files there. Instead, all files are created in the object +directory. It is of course not true for project-aware IDEs, whose purpose it is +to create the source files. + +@geindex Object_Dir (GNAT Project Manager) + +The object directory is specified through the @strong{Object_Dir} attribute. +Its value is the path to the object directory, either absolute or +relative to the directory containing the project file. This +directory must already exist and be readable and writable, although +some tools have a switch to create the directory if needed (See +the switch @cite{-p} for @emph{gnatmake} +and @emph{gprbuild}). + +If the attribute @cite{Object_Dir} is not specified, it defaults to +the project directory, that is the directory containing the project file. + +For our example, we can specify the object dir in this way: + +@c code-block: ada-project +@c +@c project Build is +@c for Source_Dirs use ("common"); +@c for Object_Dir use "obj"; -- <<<< +@c end Build; + +As mentioned earlier, there is a single object directory per project. As a +result, if you have an existing system where the object files are spread across +several directories, you can either move all of them into the same directory if +you want to build it with a single project file, or study the section on +subsystems (see @ref{14e,,Organizing Projects into Subsystems}) to see how each +separate object directory can be associated with one of the subsystems +constituting the application. + +When the @emph{linker} is called, it usually creates an executable. By +default, this executable is placed in the object directory of the project. It +might be convenient to store it in its own directory. + +@geindex Exec_Dir (GNAT Project Manager) + +This can be done through the @cite{Exec_Dir} attribute, which, like +@emph{Object_Dir} contains a single absolute or relative path and must point to +an existing and writable directory, unless you ask the tool to create it on +your behalf. When not specified, It defaults to the object directory and +therefore to the project file's directory if neither @emph{Object_Dir} nor +@emph{Exec_Dir} was specified. + +In the case of the example, let's place the executable in the root +of the hierarchy, ie the same directory as @code{build.gpr}. Hence +the project file is now + +@c code-block: ada-project +@c +@c project Build is +@c for Source_Dirs use ("common"); +@c for Object_Dir use "obj"; +@c for Exec_Dir use "."; -- <<<< +@c end Build; + +@node Main Subprograms,Tools Options in Project Files,Object and Exec Directory,Building With Projects +@anchor{gnat_ugn/gnat_project_manager id6}@anchor{15c}@anchor{gnat_ugn/gnat_project_manager main-subprograms}@anchor{15d} +@subsection Main Subprograms + + +In the previous section, executables were mentioned. The project manager needs +to be taught what they are. In a project file, an executable is indicated by +pointing to the source file of a main subprogram. In C this is the file that +contains the @cite{main} function, and in Ada the file that contains the main +unit. -@node Mode Switches for gnatmake -@section Mode Switches for @command{gnatmake} +There can be any number of such main files within a given project, and thus +several executables can be built in the context of a single project file. Of +course, one given executable might not (and in fact will not) need all the +source files referenced by the project. As opposed to other build environments +such as @emph{makefile}, one does not need to specify the list of +dependencies of each executable, the project-aware builder knows enough of the +semantics of the languages to build and link only the necessary elements. + +@geindex Main (GNAT Project Manager) + +The list of main files is specified via the @strong{Main} attribute. It contains +a list of file names (no directories). If a project defines this +attribute, it is not necessary to identify main files on the +command line when invoking a builder, and editors like +@emph{GPS} will be able to create extra menus to spawn or debug the +corresponding executables. + +@c code-block: ada-project +@c +@c project Build is +@c for Source_Dirs use ("common"); +@c for Object_Dir use "obj"; +@c for Exec_Dir use "."; +@c for Main use ("proc.adb"); -- <<<< +@c end Build; + +If this attribute is defined in the project, then spawning the builder +with a command such as + +@example +gprbuild -Pbuild +@end example + +automatically builds all the executables corresponding to the files +listed in the @emph{Main} attribute. It is possible to specify one +or more executables on the command line to build a subset of them. + +@node Tools Options in Project Files,Compiling with Project Files,Main Subprograms,Building With Projects +@anchor{gnat_ugn/gnat_project_manager tools-options-in-project-files}@anchor{15e}@anchor{gnat_ugn/gnat_project_manager id7}@anchor{15f} +@subsection Tools Options in Project Files + + +We now have a project file that fully describes our environment, and can be +used to build the application with a simple @emph{gprbuild} command as seen +in the previous section. In fact, the empty project we showed immediately at +the beginning (with no attribute at all) could already fulfill that need if it +was put in the @code{common} directory. + +Of course, we might want more control. This section shows you how to specify +the compilation switches that the various tools involved in the building of the +executable should use. + +@geindex command line length (GNAT Project Manager) + +Since source names and locations are described in the project file, it is not +necessary to use switches on the command line for this purpose (switches such +as -I for gcc). This removes a major source of command line length overflow. +Clearly, the builders will have to communicate this information one way or +another to the underlying compilers and tools they call but they usually use +response files for this and thus are not subject to command line overflows. + +Several tools participate to the creation of an executable: the compiler +produces object files from the source files; the binder (in the Ada case) +creates a "source" file that takes care, among other things, of elaboration +issues and global variable initialization; and the linker gathers everything +into a single executable that users can execute. All these tools are known to +the project manager and will be called with user defined switches from the +project files. However, we need to introduce a new project file concept to +express the switches to be used for any of the tools involved in the build. + +@geindex project file packages (GNAT Project Manager) + +A project file is subdivided into zero or more @strong{packages}, each of which +contains the attributes specific to one tool (or one set of tools). Project +files use an Ada-like syntax for packages. Package names permitted in project +files are restricted to a predefined set (see @ref{153,,Packages}), and the contents +of packages are limited to a small set of constructs and attributes +(see @ref{152,,Attributes}). + +Our example project file can be extended with the following empty packages. At +this stage, they could all be omitted since they are empty, but they show which +packages would be involved in the build process. + +@c code-block: ada-project +@c +@c project Build is +@c for Source_Dirs use ("common"); +@c for Object_Dir use "obj"; +@c for Exec_Dir use "."; +@c for Main use ("proc.adb"); +@c +@c package Builder is --<<< for gnatmake and gprbuild +@c end Builder; +@c +@c package Compiler is --<<< for the compiler +@c end Compiler; +@c +@c package Binder is --<<< for the binder +@c end Binder; +@c +@c package Linker is --<<< for the linker +@c end Linker; +@c end Build; + +Let's first examine the compiler switches. As stated in the initial description +of the example, we want to compile all files with @emph{-O2}. This is a +compiler switch, although it is usual, on the command line, to pass it to the +builder which then passes it to the compiler. It is recommended to use directly +the right package, which will make the setup easier to understand for other +people. + +Several attributes can be used to specify the switches: + +@geindex Default_Switches (GNAT Project Manager) + +@strong{Default_Switches}: -@noindent -The mode switches (referred to as @code{mode_switches}) allow the -inclusion of switches that are to be passed to the compiler itself, the -binder or the linker. The effect of a mode switch is to cause all -subsequent switches up to the end of the switch list, or up to the next -mode switch, to be interpreted as switches to be passed on to the -designated component of GNAT. +@quotation -@table @option -@c !sort! -@item -cargs @var{switches} -@cindex @option{-cargs} (@command{gnatmake}) -Compiler switches. Here @var{switches} is a list of switches -that are valid switches for @command{gcc}. They will be passed on to -all compile steps performed by @command{gnatmake}. - -@item -bargs @var{switches} -@cindex @option{-bargs} (@command{gnatmake}) -Binder switches. Here @var{switches} is a list of switches -that are valid switches for @code{gnatbind}. They will be passed on to -all bind steps performed by @command{gnatmake}. - -@item -largs @var{switches} -@cindex @option{-largs} (@command{gnatmake}) -Linker switches. Here @var{switches} is a list of switches -that are valid switches for @command{gnatlink}. They will be passed on to -all link steps performed by @command{gnatmake}. - -@item -margs @var{switches} -@cindex @option{-margs} (@command{gnatmake}) -Make switches. The switches are directly interpreted by @command{gnatmake}, -regardless of any previous occurrence of @option{-cargs}, @option{-bargs} -or @option{-largs}. -@end table - -@node Notes on the Command Line -@section Notes on the Command Line - -@noindent -This section contains some additional useful notes on the operation -of the @command{gnatmake} command. +This is the first mention in this manual of an @strong{indexed attribute}. When +this attribute is defined, one must supply an @emph{index} in the form of a +literal string. +In the case of @emph{Default_Switches}, the index is the name of the +language to which the switches apply (since a different compiler will +likely be used for each language, and each compiler has its own set of +switches). The value of the attribute is a list of switches. + +In this example, we want to compile all Ada source files with the switch +@emph{-O2}, and the resulting project file is as follows +(only the @cite{Compiler} package is shown): + +@c code-block: ada-project +@c +@c package Compiler is +@c for Default_Switches ("Ada") use ("-O2"); +@c end Compiler; +@end quotation -@itemize @bullet -@item -@cindex Recompilation, by @command{gnatmake} -If @command{gnatmake} finds no ALI files, it recompiles the main program -and all other units required by the main program. -This means that @command{gnatmake} -can be used for the initial compile, as well as during subsequent steps of -the development cycle. +@geindex Switches (GNAT Project Manager) -@item -If you enter @code{gnatmake @var{file}.adb}, where @file{@var{file}.adb} -is a subunit or body of a generic unit, @command{gnatmake} recompiles -@file{@var{file}.adb} (because it finds no ALI) and stops, issuing a -warning. +@strong{Switches}: -@item -In @command{gnatmake} the switch @option{-I} -is used to specify both source and -library file paths. Use @option{-aI} -instead if you just want to specify -source paths only and @option{-aO} -if you want to specify library paths -only. +@quotation -@item -@command{gnatmake} will ignore any files whose ALI file is write-protected. -This may conveniently be used to exclude standard libraries from -consideration and in particular it means that the use of the -@option{-f} switch will not recompile these files -unless @option{-a} is also specified. +In some cases, we might want to use specific switches +for one or more files. For instance, compiling @code{proc.adb} might not be +possible at high level of optimization because of a compiler issue. +In such a case, the @emph{Switches} +attribute (indexed on the file name) can be used and will override the +switches defined by @emph{Default_Switches}. Our project file would +become: + +@c code-block: ada-project +@c +@c +@c package Compiler is +@c for Default_Switches ("Ada") +@c use ("-O2"); +@c for Switches ("proc.adb") +@c use ("-O0"); +@c end Compiler; + +@cite{Switches} may take a pattern as an index, such as in: + +@c code-block: ada-project +@c +@c package Compiler is +@c for Default_Switches ("Ada") +@c use ("-O2"); +@c for Switches ("pkg*") +@c use ("-O0"); +@c end Compiler; + +Sources @code{pkg.adb} and @code{pkg-child.adb} would be compiled with -O0, +not -O2. + +@cite{Switches} can also be given a language name as index instead of a file +name in which case it has the same semantics as @emph{Default_Switches}. +However, indexes with wild cards are never valid for language name. +@end quotation -@item -@command{gnatmake} has been designed to make the use of Ada libraries -particularly convenient. Assume you have an Ada library organized -as follows: @i{obj-dir} contains the objects and ALI files for -of your Ada compilation units, -whereas @i{include-dir} contains the -specs of these units, but no bodies. Then to compile a unit -stored in @code{main.adb}, which uses this Ada library you would just type +@geindex Local_Configuration_Pragmas (GNAT Project Manager) -@smallexample -$ gnatmake -aI@var{include-dir} -aL@var{obj-dir} main -@end smallexample +@strong{Local_Configuration_Pragmas}: -@item -Using @command{gnatmake} along with the -@option{-m (minimal recompilation)} -switch provides a mechanism for avoiding unnecessary recompilations. Using -this switch, -you can update the comments/format of your -source files without having to recompile everything. Note, however, that -adding or deleting lines in a source files may render its debugging -info obsolete. If the file in question is a spec, the impact is rather -limited, as that debugging info will only be useful during the -elaboration phase of your program. For bodies the impact can be more -significant. In all events, your debugger will warn you if a source file -is more recent than the corresponding object, and alert you to the fact -that the debugging information may be out of date. +@quotation + +This attribute may specify the path +of a file containing configuration pragmas for use by the Ada compiler, +such as @cite{pragma Restrictions (No_Tasking)}. These pragmas will be +used for all the sources of the project. +@end quotation + +The switches for the other tools are defined in a similar manner through the +@strong{Default_Switches} and @strong{Switches} attributes, respectively in the +@emph{Builder} package (for @emph{gnatmake} and @emph{gprbuild}), +the @emph{Binder} package (binding Ada executables) and the @emph{Linker} +package (for linking executables). + +@node Compiling with Project Files,Executable File Names,Tools Options in Project Files,Building With Projects +@anchor{gnat_ugn/gnat_project_manager compiling-with-project-files}@anchor{160}@anchor{gnat_ugn/gnat_project_manager id8}@anchor{161} +@subsection Compiling with Project Files + + +Now that our project files are written, let's build our executable. +Here is the command we would use from the command line: + +@example +gnatmake -Pbuild +@end example + +This will automatically build the executables specified through the +@emph{Main} attribute: for each, it will compile or recompile the +sources for which the object file does not exist or is not up-to-date; it +will then run the binder; and finally run the linker to create the +executable itself. + +@emph{gnatmake} only knows how to handle Ada files. By using +@emph{gprbuild} as a builder, you could automatically manage C files the +same way: create the file @code{utils.c} in the @code{common} directory, +set the attribute @emph{Languages} to @cite{"(Ada@comma{} C)"}, and run + +@example +gprbuild -Pbuild +@end example + +Gprbuild knows how to recompile the C files and will +recompile them only if one of their dependencies has changed. No direct +indication on how to build the various elements is given in the +project file, which describes the project properties rather than a +set of actions to be executed. Here is the invocation of +@emph{gprbuild} when building a multi-language program: + +@example +$ gprbuild -Pbuild +gcc -c proc.adb +gcc -c pack.adb +gcc -c utils.c +gprbind proc +... +gcc proc.o -o proc +@end example + +Notice the three steps described earlier: + + +@itemize * + +@item +The first three gcc commands correspond to the compilation phase. + +@item +The gprbind command corresponds to the post-compilation phase. + +@item +The last gcc command corresponds to the final link. @end itemize -@node How gnatmake Works -@section How @command{gnatmake} Works +@geindex -v option (for GPRbuild) + +The default output of GPRbuild's execution is kept reasonably simple and easy +to understand. In particular, some of the less frequently used commands are not +shown, and some parameters are abbreviated. So it is not possible to rerun the +effect of the @emph{gprbuild} command by cut-and-pasting its output. +GPRbuild's option @cite{-v} provides a much more verbose output which includes, +among other information, more complete compilation, post-compilation and link +commands. + +@node Executable File Names,Avoid Duplication With Variables,Compiling with Project Files,Building With Projects +@anchor{gnat_ugn/gnat_project_manager executable-file-names}@anchor{162}@anchor{gnat_ugn/gnat_project_manager id9}@anchor{163} +@subsection Executable File Names + + +@geindex Executable (GNAT Project Manager) + +By default, the executable name corresponding to a main file is +computed from the main source file name. Through the attribute +@strong{Builder.Executable}, it is possible to change this default. + +For instance, instead of building @emph{proc} (or @emph{proc.exe} +on Windows), we could configure our project file to build "proc1" +(resp proc1.exe) with the following addition: + +@example +project Build is + ... -- same as before + package Builder is + for Executable ("proc.adb") use "proc1"; + end Builder +end Build; +@end example + +@geindex Executable_Suffix (GNAT Project Manager) + +Attribute @strong{Executable_Suffix}, when specified, may change the suffix +of the executable files, when no attribute @cite{Executable} applies: +its value replaces the platform-specific executable suffix. +The default executable suffix is empty on UNIX and ".exe" on Windows. + +It is also possible to change the name of the produced executable by using the +command line switch @emph{-o}. When several mains are defined in the project, +it is not possible to use the @emph{-o} switch and the only way to change the +names of the executable is provided by Attributes @cite{Executable} and +@cite{Executable_Suffix}. + +@node Avoid Duplication With Variables,Naming Schemes,Executable File Names,Building With Projects +@anchor{gnat_ugn/gnat_project_manager id10}@anchor{164}@anchor{gnat_ugn/gnat_project_manager avoid-duplication-with-variables}@anchor{165} +@subsection Avoid Duplication With Variables + + +To illustrate some other project capabilities, here is a slightly more complex +project using similar sources and a main program in C: + +@example +project C_Main is + for Languages use ("Ada", "C"); + for Source_Dirs use ("common"); + for Object_Dir use "obj"; + for Main use ("main.c"); + package Compiler is + C_Switches := ("-pedantic"); + for Default_Switches ("C") use C_Switches; + for Default_Switches ("Ada") use ("-gnaty"); + for Switches ("main.c") use C_Switches & ("-g"); + end Compiler; +end C_Main; +@end example + +This project has many similarities with the previous one. +As expected, its @cite{Main} attribute now refers to a C source. +The attribute @emph{Exec_Dir} is now omitted, thus the resulting +executable will be put in the directory @code{obj}. + +The most noticeable difference is the use of a variable in the +@emph{Compiler} package to store settings used in several attributes. +This avoids text duplication, and eases maintenance (a single place to +modify if we want to add new switches for C files). We will revisit +the use of variables in the context of scenarios (see @ref{14c,,Scenarios in Projects}). + +In this example, we see how the file @code{main.c} can be compiled with +the switches used for all the other C files, plus @emph{-g}. +In this specific situation the use of a variable could have been +replaced by a reference to the @cite{Default_Switches} attribute: + +@example +for Switches ("c_main.c") use Compiler'Default_Switches ("C") & ("-g"); +@end example + +Note the tick (@emph{'}) used to refer to attributes defined in a package. + +Here is the output of the GPRbuild command using this project: + +@example +$ gprbuild -Pc_main +gcc -c -pedantic -g main.c +gcc -c -gnaty proc.adb +gcc -c -gnaty pack.adb +gcc -c -pedantic utils.c +gprbind main.bexch +... +gcc main.o -o main +@end example -@noindent -Generally @command{gnatmake} automatically performs all necessary -recompilations and you don't need to worry about how it works. However, -it may be useful to have some basic understanding of the @command{gnatmake} -approach and in particular to understand how it uses the results of -previous compilations without incorrectly depending on them. +The default switches for Ada sources, +the default switches for C sources (in the compilation of @code{lib.c}), +and the specific switches for @code{main.c} have all been taken into +account. -First a definition: an object file is considered @dfn{up to date} if the -corresponding ALI file exists and if all the source files listed in the -dependency section of this ALI file have time stamps matching those in -the ALI file. This means that neither the source file itself nor any -files that it depends on have been modified, and hence there is no need -to recompile this file. +@node Naming Schemes,Installation,Avoid Duplication With Variables,Building With Projects +@anchor{gnat_ugn/gnat_project_manager id11}@anchor{166}@anchor{gnat_ugn/gnat_project_manager naming-schemes}@anchor{14b} +@subsection Naming Schemes -@command{gnatmake} works by first checking if the specified main unit is up -to date. If so, no compilations are required for the main unit. If not, -@command{gnatmake} compiles the main program to build a new ALI file that -reflects the latest sources. Then the ALI file of the main unit is -examined to find all the source files on which the main program depends, -and @command{gnatmake} recursively applies the above procedure on all these -files. -This process ensures that @command{gnatmake} only trusts the dependencies -in an existing ALI file if they are known to be correct. Otherwise it -always recompiles to determine a new, guaranteed accurate set of -dependencies. As a result the program is compiled ``upside down'' from what may -be more familiar as the required order of compilation in some other Ada -systems. In particular, clients are compiled before the units on which -they depend. The ability of GNAT to compile in any order is critical in -allowing an order of compilation to be chosen that guarantees that -@command{gnatmake} will recompute a correct set of new dependencies if -necessary. +Sometimes an Ada software system is ported from one compilation environment to +another (say GNAT), and the file are not named using the default GNAT +conventions. Instead of changing all the file names, which for a variety of +reasons might not be possible, you can define the relevant file naming scheme +in the @strong{Naming} package of your project file. -When invoking @command{gnatmake} with several @var{file_names}, if a unit is -imported by several of the executables, it will be recompiled at most once. +The naming scheme has two distinct goals for the project manager: it +allows finding of source files when searching in the source +directories, and given a source file name it makes it possible to guess +the associated language, and thus the compiler to use. -Note: when using non-standard naming conventions -(@pxref{Using Other File Names}), changing through a configuration pragmas -file the version of a source and invoking @command{gnatmake} to recompile may -have no effect, if the previous version of the source is still accessible -by @command{gnatmake}. It may be necessary to use the switch --f. +Note that the use by the Ada compiler of pragmas Source_File_Name is not +supported when using project files. You must use the features described in this +paragraph. You can however specify other configuration pragmas. -@node Examples of gnatmake Usage -@section Examples of @command{gnatmake} Usage +The following attributes can be defined in package @cite{Naming}: -@table @code -@item gnatmake hello.adb -Compile all files necessary to bind and link the main program -@file{hello.adb} (containing unit @code{Hello}) and bind and link the -resulting object files to generate an executable file @file{hello}. +@geindex Casing (GNAT Project Manager) -@item gnatmake main1 main2 main3 -Compile all files necessary to bind and link the main programs -@file{main1.adb} (containing unit @code{Main1}), @file{main2.adb} -(containing unit @code{Main2}) and @file{main3.adb} -(containing unit @code{Main3}) and bind and link the resulting object files -to generate three executable files @file{main1}, -@file{main2} -and @file{main3}. +@strong{Casing}: -@item gnatmake -q Main_Unit -cargs -O2 -bargs -l +@quotation -Compile all files necessary to bind and link the main program unit -@code{Main_Unit} (from file @file{main_unit.adb}). All compilations will -be done with optimization level 2 and the order of elaboration will be -listed by the binder. @command{gnatmake} will operate in quiet mode, not -displaying commands it is executing. -@end table +Its value must be one of @cite{"lowercase"} (the default if +unspecified), @cite{"uppercase"} or @cite{"mixedcase"}. It describes the +casing of file names with regards to the Ada unit name. Given an Ada unit +My_Unit, the file name will respectively be @code{my_unit.adb} (lowercase), +@code{MY_UNIT.ADB} (uppercase) or @code{My_Unit.adb} (mixedcase). +On Windows, file names are case insensitive, so this attribute is +irrelevant. +@end quotation -@c ************************* -@node Improving Performance -@chapter Improving Performance -@cindex Improving performance +@geindex Dot_Replacement (GNAT Project Manager) -@noindent -This chapter presents several topics related to program performance. -It first describes some of the tradeoffs that need to be considered -and some of the techniques for making your program run faster. -It then documents -@ifclear FSFEDITION -the @command{gnatelim} tool and -@end ifclear -unused subprogram/data -elimination feature, which can reduce the size of program executables. +@strong{Dot_Replacement}: -@ifnottex -@menu -* Performance Considerations:: -* Text_IO Suggestions:: -@ifclear FSFEDITION -* Reducing Size of Ada Executables with gnatelim:: -@end ifclear -* Reducing Size of Executables with unused subprogram/data elimination:: -@end menu -@end ifnottex +@quotation -@c ***************************** -@node Performance Considerations -@section Performance Considerations +This attribute specifies the string that should replace the "." in unit +names. Its default value is @cite{"-"} so that a unit +@cite{Parent.Child} is expected to be found in the file +@code{parent-child.adb}. The replacement string must satisfy the following +requirements to avoid ambiguities in the naming scheme: -@noindent -The GNAT system provides a number of options that allow a trade-off -between -@itemize @bullet -@item -performance of the generated code +@itemize * -@item -speed of compilation +@item +It must not be empty -@item -minimization of dependences and recompilation +@item +It cannot start or end with an alphanumeric character -@item -the degree of run-time checking. +@item +It cannot be a single underscore + +@item +It cannot start with an underscore followed by an alphanumeric + +@item +It cannot contain a dot @cite{'.'} except if the entire string is @cite{"."} @end itemize +@end quotation -@noindent -The defaults (if no options are selected) aim at improving the speed -of compilation and minimizing dependences, at the expense of performance -of the generated code: +@geindex Spec_Suffix (GNAT Project Manager) -@itemize @bullet -@item -no optimization +@geindex Specification_Suffix (GNAT Project Manager) -@item -no inlining of subprogram calls +@strong{Spec_Suffix} and @strong{Specification_Suffix}: -@item -all run-time checks enabled except overflow and elaboration checks +@quotation + +For Ada, these attributes give the suffix used in file names that contain +specifications. For other languages, they give the extension for files +that contain declaration (header files in C for instance). The attribute +is indexed on the language. +The two attributes are equivalent, but the latter is obsolescent. + +If the value of the attribute is the empty string, it indicates to the +Project Manager that the only specifications/header files for the language +are those specified with attributes @cite{Spec} or +@cite{Specification_Exceptions}. + +If @cite{Spec_Suffix ("Ada")} is not specified, then the default is +@cite{".ads"}. + +A non empty value must satisfy the following requirements: + + +@itemize * + +@item +It must include at least one dot + +@item +If @cite{Dot_Replacement} is a single dot, then it cannot include +more than one dot. @end itemize +@end quotation -@noindent -These options are suitable for most program development purposes. This -chapter describes how you can modify these choices, and also provides -some guidelines on debugging optimized code. +@geindex Body_Suffix (GNAT Project Manager) -@menu -* Controlling Run-Time Checks:: -* Use of Restrictions:: -* Optimization Levels:: -* Debugging Optimized Code:: -* Inlining of Subprograms:: -* Vectorization of loops:: -* Other Optimization Switches:: -* Optimization and Strict Aliasing:: -* Aliased Variables and Optimization:: -* Atomic Variables and Optimization:: -* Passive Task Optimization:: +@geindex Implementation_Suffix (GNAT Project Manager) -@end menu +@strong{Body_Suffix} and @strong{Implementation_Suffix}: -@node Controlling Run-Time Checks -@subsection Controlling Run-Time Checks +@quotation -@noindent -By default, GNAT generates all run-time checks, except integer overflow -checks, stack overflow checks, and checks for access before elaboration on -subprogram calls. The latter are not required in default mode, because all -necessary checking is done at compile time. -@cindex @option{-gnatp} (@command{gcc}) -@cindex @option{-gnato} (@command{gcc}) -Two gnat switches, @option{-gnatp} and @option{-gnato} allow this default to -be modified. @xref{Run-Time Checks}. +These attributes give the extension used for file names that contain +code (bodies in Ada). They are indexed on the language. The second +version is obsolescent and fully replaced by the first attribute. + +For each language of a project, one of these two attributes need to be +specified, either in the project itself or in the configuration project file. + +If the value of the attribute is the empty string, it indicates to the +Project Manager that the only source files for the language +are those specified with attributes @cite{Body} or +@cite{Implementation_Exceptions}. + +These attributes must satisfy the same requirements as @cite{Spec_Suffix}. +In addition, they must be different from any of the values in +@cite{Spec_Suffix}. +If @cite{Body_Suffix ("Ada")} is not specified, then the default is +@cite{".adb"}. + +If @cite{Body_Suffix ("Ada")} and @cite{Spec_Suffix ("Ada")} end with the +same string, then a file name that ends with the longest of these two +suffixes will be a body if the longest suffix is @cite{Body_Suffix ("Ada")} +or a spec if the longest suffix is @cite{Spec_Suffix ("Ada")}. + +If the suffix does not start with a '.', a file with a name exactly equal to +the suffix will also be part of the project (for instance if you define the +suffix as @cite{Makefile.in}, a file called @code{Makefile.in} will be part +of the project. This capability is usually not interesting when building. +However, it might become useful when a project is also used to +find the list of source files in an editor, like the GNAT Programming System +(GPS). +@end quotation -Our experience is that the default is suitable for most development -purposes. +@geindex Separate_Suffix (GNAT Project Manager) -We treat integer overflow specially because these -are quite expensive and in our experience are not as important as other -run-time checks in the development process. Note that division by zero -is not considered an overflow check, and divide by zero checks are -generated where required by default. +@strong{Separate_Suffix}: -Elaboration checks are off by default, and also not needed by default, since -GNAT uses a static elaboration analysis approach that avoids the need for -run-time checking. This manual contains a full chapter discussing the issue -of elaboration checks, and if the default is not satisfactory for your use, -you should read this chapter. +@quotation -For validity checks, the minimal checks required by the Ada Reference -Manual (for case statements and assignments to array elements) are on -by default. These can be suppressed by use of the @option{-gnatVn} switch. -Note that in Ada 83, there were no validity checks, so if the Ada 83 mode -is acceptable (or when comparing GNAT performance with an Ada 83 compiler), -it may be reasonable to routinely use @option{-gnatVn}. Validity checks -are also suppressed entirely if @option{-gnatp} is used. - -@cindex Overflow checks -@cindex Checks, overflow -@findex Suppress -@findex Unsuppress -@cindex pragma Suppress -@cindex pragma Unsuppress -Note that the setting of the switches controls the default setting of -the checks. They may be modified using either @code{pragma Suppress} (to -remove checks) or @code{pragma Unsuppress} (to add back suppressed -checks) in the program source. +This attribute is specific to Ada. It denotes the suffix used in file names +that contain separate bodies. If it is not specified, then it defaults to +same value as @cite{Body_Suffix ("Ada")}. -@node Use of Restrictions -@subsection Use of Restrictions +The value of this attribute cannot be the empty string. -@noindent -The use of pragma Restrictions allows you to control which features are -permitted in your program. Apart from the obvious point that if you avoid -relatively expensive features like finalization (enforceable by the use -of pragma Restrictions (No_Finalization), the use of this pragma does not -affect the generated code in most cases. +Otherwise, the same rules apply as for the +@cite{Body_Suffix} attribute. The only accepted index is "Ada". +@end quotation -One notable exception to this rule is that the possibility of task abort -results in some distributed overhead, particularly if finalization or -exception handlers are used. The reason is that certain sections of code -have to be marked as non-abortable. +@strong{Spec} or @strong{Specification}: -If you use neither the @code{abort} statement, nor asynchronous transfer -of control (@code{select @dots{} then abort}), then this distributed overhead -is removed, which may have a general positive effect in improving -overall performance. Especially code involving frequent use of tasking -constructs and controlled types will show much improved performance. -The relevant restrictions pragmas are +@quotation -@smallexample @c ada - @b{pragma} Restrictions (No_Abort_Statements); - @b{pragma} Restrictions (Max_Asynchronous_Select_Nesting => 0); -@end smallexample +@geindex Spec (GNAT Project Manager) -@noindent -It is recommended that these restriction pragmas be used if possible. Note -that this also means that you can write code without worrying about the -possibility of an immediate abort at any point. +@geindex Specification (GNAT Project Manager) -@node Optimization Levels -@subsection Optimization Levels -@cindex @option{-O} (@command{gcc}) +This attribute @cite{Spec} can be used to define the source file name for a +given Ada compilation unit's spec. The index is the literal name of the Ada +unit (case insensitive). The value is the literal base name of the file that +contains this unit's spec (case sensitive or insensitive depending on the +operating system). This attribute allows the definition of exceptions to the +general naming scheme, in case some files do not follow the usual +convention. -@noindent -Without any optimization option, -the compiler's goal is to reduce the cost of -compilation and to make debugging produce the expected results. -Statements are independent: if you stop the program with a breakpoint between -statements, you can then assign a new value to any variable or change -the program counter to any other statement in the subprogram and get exactly -the results you would expect from the source code. +When a source file contains several units, the relative position of the unit +can be indicated. The first unit in the file is at position 1 -Turning on optimization makes the compiler attempt to improve the -performance and/or code size at the expense of compilation time and -possibly the ability to debug the program. +@example +for Spec ("MyPack.MyChild") use "mypack.mychild.spec"; +for Spec ("top") use "foo.a" at 1; +for Spec ("foo") use "foo.a" at 2; +@end example +@end quotation -If you use multiple --O options, with or without level numbers, -the last such option is the one that is effective. +@geindex Body (GNAT Project Manager) -@noindent -The default is optimization off. This results in the fastest compile -times, but GNAT makes absolutely no attempt to optimize, and the -generated programs are considerably larger and slower than when -optimization is enabled. You can use the -@option{-O} switch (the permitted forms are @option{-O0}, @option{-O1} -@option{-O2}, @option{-O3}, and @option{-Os}) -to @command{gcc} to control the optimization level: +@geindex Implementation (GNAT Project Manager) -@table @option -@item -O0 -No optimization (the default); -generates unoptimized code but has -the fastest compilation time. +@strong{Body} or @strong{Implementation}: -Note that many other compilers do fairly extensive optimization -even if ``no optimization'' is specified. With gcc, it is -very unusual to use -O0 for production if -execution time is of any concern, since -O0 -really does mean no optimization at all. This difference between -gcc and other compilers should be kept in mind when doing -performance comparisons. +@quotation -@item -O1 -Moderate optimization; -optimizes reasonably well but does not -degrade compilation time significantly. +These attribute play the same role as @emph{Spec} for Ada bodies. +@end quotation -@item -O2 -Full optimization; -generates highly optimized code and has -the slowest compilation time. +@geindex Specification_Exceptions (GNAT Project Manager) -@item -O3 -Full optimization as in @option{-O2}; -also uses more aggressive automatic inlining of subprograms within a unit -(@pxref{Inlining of Subprograms}) and attempts to vectorize loops. +@geindex Implementation_Exceptions (GNAT Project Manager) -@item -Os -Optimize space usage (code and data) of resulting program. +@strong{Specification_Exceptions} and @strong{Implementation_Exceptions}: + +@quotation + +These attributes define exceptions to the naming scheme for languages +other than Ada. They are indexed on the language name, and contain +a list of file names respectively for headers and source code. +@end quotation + +For example, the following package models the Apex file naming rules: + +@example +package Naming is + for Casing use "lowercase"; + for Dot_Replacement use "."; + for Spec_Suffix ("Ada") use ".1.ada"; + for Body_Suffix ("Ada") use ".2.ada"; +end Naming; +@end example + +@node Installation,Distributed support,Naming Schemes,Building With Projects +@anchor{gnat_ugn/gnat_project_manager id12}@anchor{167}@anchor{gnat_ugn/gnat_project_manager installation}@anchor{168} +@subsection Installation + + +After building an application or a library it is often required to +install it into the development environment. For instance this step is +required if the library is to be used by another application. +The @emph{gprinstall} tool provides an easy way to install +libraries, executable or object code generated during the build. The +@strong{Install} package can be used to change the default locations. + +The following attributes can be defined in package @cite{Install}: + +@geindex Active (GNAT Project Manager) + + +@table @asis + +@item @strong{Active} + +Whether the project is to be installed, values are @cite{true} +(default) or @cite{false}. @end table -@noindent -Higher optimization levels perform more global transformations on the -program and apply more expensive analysis algorithms in order to generate -faster and more compact code. The price in compilation time, and the -resulting improvement in execution time, -both depend on the particular application and the hardware environment. -You should experiment to find the best level for your application. +@geindex Artifacts (GNAT Project Manager) -Since the precise set of optimizations done at each level will vary from -release to release (and sometime from target to target), it is best to think -of the optimization settings in general terms. -@xref{Optimize Options,, Options That Control Optimization, gcc, Using -the GNU Compiler Collection (GCC)}, for details about -the @option{-O} settings and a number of @option{-f} options that -individually enable or disable specific optimizations. +@strong{Artifacts} -Unlike some other compilation systems, @command{gcc} has -been tested extensively at all optimization levels. There are some bugs -which appear only with optimization turned on, but there have also been -bugs which show up only in @emph{unoptimized} code. Selecting a lower -level of optimization does not improve the reliability of the code -generator, which in practice is highly reliable at all optimization -levels. +@quotation -Note regarding the use of @option{-O3}: The use of this optimization level -is generally discouraged with GNAT, since it often results in larger -executables which may run more slowly. See further discussion of this point -in @ref{Inlining of Subprograms}. +An array attribute to declare a set of files not part of the sources +to be installed. The array discriminant is the directory where the +file is to be installed. If a relative directory then Prefix (see +below) is prepended. +@end quotation -@node Debugging Optimized Code -@subsection Debugging Optimized Code -@cindex Debugging optimized code -@cindex Optimization and debugging +@geindex Prefix (GNAT Project Manager) -@noindent -Although it is possible to do a reasonable amount of debugging at -nonzero optimization levels, -the higher the level the more likely that -source-level constructs will have been eliminated by optimization. -For example, if a loop is strength-reduced, the loop -control variable may be completely eliminated and thus cannot be -displayed in the debugger. -This can only happen at @option{-O2} or @option{-O3}. -Explicit temporary variables that you code might be eliminated at -level @option{-O1} or higher. +@strong{Prefix}: -The use of the @option{-g} switch, -@cindex @option{-g} (@command{gcc}) -which is needed for source-level debugging, -affects the size of the program executable on disk, -and indeed the debugging information can be quite large. -However, it has no effect on the generated code (and thus does not -degrade performance) +@quotation -Since the compiler generates debugging tables for a compilation unit before -it performs optimizations, the optimizing transformations may invalidate some -of the debugging data. You therefore need to anticipate certain -anomalous situations that may arise while debugging optimized code. -These are the most common cases: +Root directory for the installation. +@end quotation -@enumerate -@item -@i{The ``hopping Program Counter'':} Repeated @code{step} or @code{next} -commands show -the PC bouncing back and forth in the code. This may result from any of -the following optimizations: +@strong{Exec_Subdir} -@itemize @bullet -@item -@i{Common subexpression elimination:} using a single instance of code for a -quantity that the source computes several times. As a result you -may not be able to stop on what looks like a statement. +@quotation -@item -@i{Invariant code motion:} moving an expression that does not change within a -loop, to the beginning of the loop. +Subdirectory of @strong{Prefix} where executables are to be +installed. Default is @strong{bin}. +@end quotation -@item -@i{Instruction scheduling:} moving instructions so as to -overlap loads and stores (typically) with other code, or in -general to move computations of values closer to their uses. Often -this causes you to pass an assignment statement without the assignment -happening and then later bounce back to the statement when the -value is actually needed. Placing a breakpoint on a line of code -and then stepping over it may, therefore, not always cause all the -expected side-effects. -@end itemize +@strong{Lib_Subdir} -@item -@i{The ``big leap'':} More commonly known as @emph{cross-jumping}, in which -two identical pieces of code are merged and the program counter suddenly -jumps to a statement that is not supposed to be executed, simply because -it (and the code following) translates to the same thing as the code -that @emph{was} supposed to be executed. This effect is typically seen in -sequences that end in a jump, such as a @code{goto}, a @code{return}, or -a @code{break} in a C @code{switch} statement. +@quotation -@item -@i{The ``roving variable'':} The symptom is an unexpected value in a variable. -There are various reasons for this effect: +Subdirectory of @strong{Prefix} where directory with the library or object +files is to be installed. Default is @strong{lib}. +@end quotation -@itemize @bullet -@item -In a subprogram prologue, a parameter may not yet have been moved to its -``home''. +@strong{Sources_Subdir} -@item -A variable may be dead, and its register re-used. This is -probably the most common cause. +@quotation -@item -As mentioned above, the assignment of a value to a variable may -have been moved. +Subdirectory of @strong{Prefix} where directory with sources is to be +installed. Default is @strong{include}. +@end quotation -@item -A variable may be eliminated entirely by value propagation or -other means. In this case, GCC may incorrectly generate debugging -information for the variable -@end itemize +@strong{Project_Subdir} -@noindent -In general, when an unexpected value appears for a local variable or parameter -you should first ascertain if that value was actually computed by -your program, as opposed to being incorrectly reported by the debugger. -Record fields or -array elements in an object designated by an access value -are generally less of a problem, once you have ascertained that the access -value is sensible. -Typically, this means checking variables in the preceding code and in the -calling subprogram to verify that the value observed is explainable from other -values (one must apply the procedure recursively to those -other values); or re-running the code and stopping a little earlier -(perhaps before the call) and stepping to better see how the variable obtained -the value in question; or continuing to step @emph{from} the point of the -strange value to see if code motion had simply moved the variable's -assignments later. -@end enumerate +@quotation -@noindent -In light of such anomalies, a recommended technique is to use @option{-O0} -early in the software development cycle, when extensive debugging capabilities -are most needed, and then move to @option{-O1} and later @option{-O2} as -the debugger becomes less critical. -Whether to use the @option{-g} switch in the release version is -a release management issue. -Note that if you use @option{-g} you can then use the @command{strip} program -on the resulting executable, -which removes both debugging information and global symbols. +Subdirectory of @strong{Prefix} where the generated project file is to be +installed. Default is @strong{share/gpr}. +@end quotation -@node Inlining of Subprograms -@subsection Inlining of Subprograms +@strong{Mode} -@noindent -A call to a subprogram in the current unit is inlined if all the -following conditions are met: +@quotation -@itemize @bullet -@item -The optimization level is at least @option{-O1}. +The installation mode, it is either @strong{dev} (default) or @strong{usage}. +See @strong{gprbuild} user's guide for details. +@end quotation -@item -The called subprogram is suitable for inlining: It must be small enough -and not contain something that @command{gcc} cannot support in inlined -subprograms. +@strong{Install_Name} -@item -@cindex pragma Inline -@findex Inline -Any one of the following applies: @code{pragma Inline} is applied to the -subprogram and the @option{-gnatn} switch is specified; the -subprogram is local to the unit and called once from within it; the -subprogram is small and optimization level @option{-O2} is specified; -optimization level @option{-O3} is specified. -@end itemize +@quotation -@noindent -Calls to subprograms in @code{with}'ed units are normally not inlined. -To achieve actual inlining (that is, replacement of the call by the code -in the body of the subprogram), the following conditions must all be true: +Specify the name to use for recording the installation. The default is +the project name without the extension. +@end quotation -@itemize @bullet -@item -The optimization level is at least @option{-O1}. +@node Distributed support,,Installation,Building With Projects +@anchor{gnat_ugn/gnat_project_manager id13}@anchor{169}@anchor{gnat_ugn/gnat_project_manager distributed-support}@anchor{16a} +@subsection Distributed support -@item -The called subprogram is suitable for inlining: It must be small enough -and not contain something that @command{gcc} cannot support in inlined -subprograms. -@item -The call appears in a body (not in a package spec). +For large projects the compilation time can become a limitation in +the development cycle. To cope with that, GPRbuild supports +distributed compilation. -@item -There is a @code{pragma Inline} for the subprogram. +The following attributes can be defined in package @cite{Remote}: -@item -The @option{-gnatn} switch is used on the command line. +@geindex Root_Dir (GNAT Project Manager) + +@strong{Root_Dir}: + +@quotation + +Root directory of the project's sources. The default value is the +project's directory. +@end quotation + +@node Organizing Projects into Subsystems,Scenarios in Projects,Building With Projects,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager organizing-projects-into-subsystems}@anchor{14e}@anchor{gnat_ugn/gnat_project_manager id14}@anchor{16b} +@section Organizing Projects into Subsystems + + +A @strong{subsystem} is a coherent part of the complete system to be built. It is +represented by a set of sources and one single object directory. A system can +be composed of a single subsystem when it is simple as we have seen in the +first section. Complex systems are usually composed of several interdependent +subsystems. A subsystem is dependent on another subsystem if knowledge of the +other one is required to build it, and in particular if visibility on some of +the sources of this other subsystem is required. Each subsystem is usually +represented by its own project file. + +In this section, the previous example is being extended. Let's assume some +sources of our @cite{Build} project depend on other sources. +For instance, when building a graphical interface, it is usual to depend upon +a graphical library toolkit such as GtkAda. Furthermore, we also need +sources from a logging module we had previously written. + +@menu +* Project Dependencies:: +* Cyclic Project Dependencies:: +* Sharing Between Projects:: +* Global Attributes:: + +@end menu + +@node Project Dependencies,Cyclic Project Dependencies,,Organizing Projects into Subsystems +@anchor{gnat_ugn/gnat_project_manager project-dependencies}@anchor{16c}@anchor{gnat_ugn/gnat_project_manager id15}@anchor{16d} +@subsection Project Dependencies + + +GtkAda comes with its own project file (appropriately called +@code{gtkada.gpr}), and we will assume we have already built a project +called @code{logging.gpr} for the logging module. With the information provided +so far in @code{build.gpr}, building the application would fail with an error +indicating that the gtkada and logging units that are relied upon by the sources +of this project cannot be found. + +This is solved by adding the following @strong{with} clauses at the beginning of our +project: + +@example +with "gtkada.gpr"; +with "a/b/logging.gpr"; +project Build is + ... -- as before +end Build; +@end example + +@geindex Externally_Built (GNAT Project Manager) + +When such a project is compiled, @emph{gprbuild} will automatically check +the other projects and recompile their sources when needed. It will also +recompile the sources from @cite{Build} when needed, and finally create the +executable. In some cases, the implementation units needed to recompile a +project are not available, or come from some third party and you do not want to +recompile it yourself. In this case, set the attribute @strong{Externally_Built} to +"true", indicating to the builder that this project can be assumed to be +up-to-date, and should not be considered for recompilation. In Ada, if the +sources of this externally built project were compiled with another version of +the compiler or with incompatible options, the binder will issue an error. + +The project's @emph{with} clause has several effects. It provides source +visibility between projects during the compilation process. It also guarantees +that the necessary object files from @cite{Logging} and @cite{GtkAda} are +available when linking @cite{Build}. + +As can be seen in this example, the syntax for importing projects is similar +to the syntax for importing compilation units in Ada. However, project files +use literal strings instead of names, and the @emph{with} clause identifies +project files rather than packages. + +Each literal string after @emph{with} is the path +(absolute or relative) to a project file. The @cite{.gpr} extension is +optional, although we recommend adding it. If no extension is specified, +and no project file with the @code{.gpr} extension is found, then +the file is searched for exactly as written in the @emph{with} clause, +that is with no extension. + +As mentioned above, the path after a @emph{with} has to be a literal +string, and you cannot use concatenation, or lookup the value of external +variables to change the directories from which a project is loaded. +A solution if you need something like this is to use aggregate projects +(see @ref{16e,,Aggregate Projects}). + +@geindex project path (GNAT Project Manager) + +When a relative path or a base name is used, the +project files are searched relative to each of the directories in the +@strong{project path}. This path includes all the directories found with the +following algorithm, in this order; the first matching file is used: + + +@itemize * + +@item +First, the file is searched relative to the directory that contains the +current project file. + +@geindex GPR_PROJECT_PATH_FILE (GNAT Project Manager) + +@geindex GPR_PROJECT_PATH (GNAT Project Manager) + +@geindex ADA_PROJECT_PATH (GNAT Project Manager) + +@item +Then it is searched relative to all the directories specified in the +environment variables @strong{GPR_PROJECT_PATH_FILE}, +@strong{GPR_PROJECT_PATH} and @strong{ADA_PROJECT_PATH} (in that order) if they exist. +The value of @strong{GPR_PROJECT_PATH_FILE}, when defined, is the path name of +a text file that contains project directory path names, one per line. +@strong{GPR_PROJECT_PATH} and @strong{ADA_PROJECT_PATH}, when defined, contain +project directory path names separated by directory separators. +@strong{ADA_PROJECT_PATH} is used for compatibility, it is recommended to +use @strong{GPR_PROJECT_PATH_FILE} or @strong{GPR_PROJECT_PATH}. + +@item +Finally, it is searched relative to the default project directories. +Such directories depend on the tool used. The locations searched in the +specified order are: + + +@itemize * + +@item +@code{<prefix>/<target>/lib/gnat} +(for @emph{gnatmake} in all cases, and for @emph{gprbuild} if option +@emph{--target} is specified) + +@item +@code{<prefix>/<target>/share/gpr} +(for @emph{gnatmake} in all cases, and for @emph{gprbuild} if option +@emph{--target} is specified) + +@item +@code{<prefix>/share/gpr/} +(for @emph{gnatmake} and @emph{gprbuild}) + +@item +@code{<prefix>/lib/gnat/} +(for @emph{gnatmake} and @emph{gprbuild}) @end itemize -Even if all these conditions are met, it may not be possible for -the compiler to inline the call, due to the length of the body, -or features in the body that make it impossible for the compiler -to do the inlining. +In our example, @code{gtkada.gpr} is found in the predefined directory if +it was installed at the same root as GNAT. +@end itemize -Note that specifying the @option{-gnatn} switch causes additional -compilation dependencies. Consider the following: +Some tools also support extending the project path from the command line, +generally through the @emph{-aP}. You can see the value of the project +path by using the @emph{gnatls -v} command. + +Any symbolic link will be fully resolved in the directory of the +importing project file before the imported project file is examined. + +Any source file in the imported project can be used by the sources of the +importing project, transitively. +Thus if @cite{A} imports @cite{B}, which imports @cite{C}, the sources of +@cite{A} may depend on the sources of @cite{C}, even if @cite{A} does not +import @cite{C} explicitly. However, this is not recommended, because if +and when @cite{B} ceases to import @cite{C}, some sources in @cite{A} will +no longer compile. @emph{gprbuild} has a switch @emph{--no-indirect-imports} +that will report such indirect dependencies. -@smallexample @c ada @cartouche -@b{package} R @b{is} - @b{procedure} Q; - @b{pragma} Inline (Q); -@b{end} R; -@b{package} @b{body} R @b{is} - @dots{} -@b{end} R; - -@b{with} R; -@b{procedure} Main @b{is} -@b{begin} - @dots{} - R.Q; -@b{end} Main; +@quotation Note +One very important aspect of a project hierarchy is that +@strong{a given source can only belong to one project} (otherwise the project manager +would not know which settings apply to it and when to recompile it). It means +that different project files do not usually share source directories or +when they do, they need to specify precisely which project owns which sources +using attribute @cite{Source_Files} or equivalent. By contrast, 2 projects +can each own a source with the same base file name as long as they live in +different directories. The latter is not true for Ada Sources because of the +correlation between source files and Ada units. +@end quotation @end cartouche -@end smallexample - -@noindent -With the default behavior (no @option{-gnatn} switch specified), the -compilation of the @code{Main} procedure depends only on its own source, -@file{main.adb}, and the spec of the package in file @file{r.ads}. This -means that editing the body of @code{R} does not require recompiling -@code{Main}. - -On the other hand, the call @code{R.Q} is not inlined under these -circumstances. If the @option{-gnatn} switch is present when @code{Main} -is compiled, the call will be inlined if the body of @code{Q} is small -enough, but now @code{Main} depends on the body of @code{R} in -@file{r.adb} as well as on the spec. This means that if this body is edited, -the main program must be recompiled. Note that this extra dependency -occurs whether or not the call is in fact inlined by @command{gcc}. -The use of front end inlining with @option{-gnatN} generates similar -additional dependencies. +@node Cyclic Project Dependencies,Sharing Between Projects,Project Dependencies,Organizing Projects into Subsystems +@anchor{gnat_ugn/gnat_project_manager id16}@anchor{16f}@anchor{gnat_ugn/gnat_project_manager cyclic-project-dependencies}@anchor{170} +@subsection Cyclic Project Dependencies + + +Cyclic dependencies are mostly forbidden: +if @cite{A} imports @cite{B} (directly or indirectly) then @cite{B} +is not allowed to import @cite{A}. However, there are cases when cyclic +dependencies would be beneficial. For these cases, another form of import +between projects exists: the @strong{limited with}. A project @cite{A} that +imports a project @cite{B} with a straight @emph{with} may also be imported, +directly or indirectly, by @cite{B} through a @cite{limited with}. + +The difference between straight @emph{with} and @cite{limited with} is that +the name of a project imported with a @cite{limited with} cannot be used in the +project importing it. In particular, its packages cannot be renamed and +its variables cannot be referred to. + +@example +with "b.gpr"; +with "c.gpr"; +project A is + for Exec_Dir use B'Exec_Dir; -- ok +end A; + +limited with "a.gpr"; -- Cyclic dependency: A -> B -> A +project B is + for Exec_Dir use A'Exec_Dir; -- not ok +end B; + +with "d.gpr"; +project C is +end C; + +limited with "a.gpr"; -- Cyclic dependency: A -> C -> D -> A +project D is + for Exec_Dir use A'Exec_Dir; -- not ok +end D; +@end example + +@node Sharing Between Projects,Global Attributes,Cyclic Project Dependencies,Organizing Projects into Subsystems +@anchor{gnat_ugn/gnat_project_manager sharing-between-projects}@anchor{171}@anchor{gnat_ugn/gnat_project_manager id17}@anchor{172} +@subsection Sharing Between Projects + + +When building an application, it is common to have similar needs in several of +the projects corresponding to the subsystems under construction. For instance, +they will all have the same compilation switches. + +As seen before (see @ref{15e,,Tools Options in Project Files}), setting compilation +switches for all sources of a subsystem is simple: it is just a matter of +adding a @cite{Compiler.Default_Switches} attribute to each project files with +the same value. Of course, that means duplication of data, and both places need +to be changed in order to recompile the whole application with different +switches. It can become a real problem if there are many subsystems and thus +many project files to edit. + +There are two main approaches to avoiding this duplication: + + +@itemize * + +@item +Since @code{build.gpr} imports @code{logging.gpr}, we could change it +to reference the attribute in Logging, either through a package renaming, +or by referencing the attribute. The following example shows both cases: + +@example +project Logging is + package Compiler is + for Switches ("Ada") + use ("-O2"); + end Compiler; + package Binder is + for Switches ("Ada") + use ("-E"); + end Binder; +end Logging; + +with "logging.gpr"; +project Build is + package Compiler renames Logging.Compiler; + package Binder is + for Switches ("Ada") use Logging.Binder'Switches ("Ada"); + end Binder; +end Build; +@end example + +The solution used for @cite{Compiler} gets the same value for all +attributes of the package, but you cannot modify anything from the +package (adding extra switches or some exceptions). The second +version is more flexible, but more verbose. + +If you need to refer to the value of a variable in an imported +project, rather than an attribute, the syntax is similar but uses +a "." rather than an apostrophe. For instance: + +@example +with "imported"; +project Main is + Var1 := Imported.Var; +end Main; +@end example + +@item +The second approach is to define the switches in a third project. +That project is set up without any sources (so that, as opposed to +the first example, none of the project plays a special role), and +will only be used to define the attributes. Such a project is +typically called @code{shared.gpr}. + +@example +abstract project Shared is + for Source_Files use (); -- no sources + package Compiler is + for Switches ("Ada") + use ("-O2"); + end Compiler; +end Shared; + +with "shared.gpr"; +project Logging is + package Compiler renames Shared.Compiler; +end Logging; + +with "shared.gpr"; +project Build is + package Compiler renames Shared.Compiler; +end Build; +@end example + +As for the first example, we could have chosen to set the attributes +one by one rather than to rename a package. The reason we explicitly +indicate that @cite{Shared} has no sources is so that it can be created +in any directory and we are sure it shares no sources with @cite{Build} +or @cite{Logging}, which of course would be invalid. + +@geindex project qualifier (GNAT Project Manager) + +Note the additional use of the @strong{abstract} qualifier in @code{shared.gpr}. +This qualifier is optional, but helps convey the message that we do not +intend this project to have sources (see @ref{173,,Qualified Projects} for +more qualifiers). +@end itemize -@cindex @option{-fno-inline} (@command{gcc}) -Note: The @option{-fno-inline} switch -can be used to prevent -all inlining. This switch overrides all other conditions and ensures -that no inlining occurs. The extra dependences resulting from -@option{-gnatn} will still be active, even if -this switch is used to suppress the resulting inlining actions. +@node Global Attributes,,Sharing Between Projects,Organizing Projects into Subsystems +@anchor{gnat_ugn/gnat_project_manager global-attributes}@anchor{174}@anchor{gnat_ugn/gnat_project_manager id18}@anchor{175} +@subsection Global Attributes -@cindex @option{-fno-inline-functions} (@command{gcc}) -Note: The @option{-fno-inline-functions} switch can be used to prevent -automatic inlining of subprograms if @option{-O3} is used. -@cindex @option{-fno-inline-small-functions} (@command{gcc}) -Note: The @option{-fno-inline-small-functions} switch can be used to prevent -automatic inlining of small subprograms if @option{-O2} is used. +We have already seen many examples of attributes used to specify a special +option of one of the tools involved in the build process. Most of those +attributes are project specific. That it to say, they only affect the invocation +of tools on the sources of the project where they are defined. -@cindex @option{-fno-inline-functions-called-once} (@command{gcc}) -Note: The @option{-fno-inline-functions-called-once} switch -can be used to prevent inlining of subprograms local to the unit -and called once from within it if @option{-O1} is used. - -Note regarding the use of @option{-O3}: @option{-gnatn} is made up of two -sub-switches @option{-gnatn1} and @option{-gnatn2} that can be directly -specified in lieu of it, @option{-gnatn} being translated into one of them -based on the optimization level. With @option{-O2} or below, @option{-gnatn} -is equivalent to @option{-gnatn1} which activates pragma @code{Inline} with -moderate inlining across modules. With @option{-O3}, @option{-gnatn} is -equivalent to @option{-gnatn2} which activates pragma @code{Inline} with -full inlining across modules. If you have used pragma @code{Inline} in appropriate cases, then it is usually much better to use @option{-O2} and @option{-gnatn} and avoid the use of @option{-O3} which has the additional -effect of inlining subprograms you did not think should be inlined. We have -found that the use of @option{-O3} may slow down the compilation and increase -the code size by performing excessive inlining, leading to increased -instruction cache pressure from the increased code size and thus minor -performance improvements. So the bottom line here is that you should not -automatically assume that @option{-O3} is better than @option{-O2}, and -indeed you should use @option{-O3} only if tests show that it actually -improves performance for your program. +There are a few additional attributes that apply to all projects in a +hierarchy as long as they are defined on the "main" project. +The main project is the project explicitly mentioned on the command-line. +The project hierarchy is the "with"-closure of the main project. -@node Vectorization of loops -@subsection Vectorization of loops -@cindex Optimization Switches +Here is a list of commonly used global attributes: -You can take advantage of the auto-vectorizer present in the @command{gcc} -back end to vectorize loops with GNAT. The corresponding command line switch -is @option{-ftree-vectorize} but, as it is enabled by default at @option{-O3} -and other aggressive optimizations helpful for vectorization also are enabled -by default at this level, using @option{-O3} directly is recommended. +@geindex Global_Configuration_Pragmas (GNAT Project Manager) -You also need to make sure that the target architecture features a supported -SIMD instruction set. For example, for the x86 architecture, you should at -least specify @option{-msse2} to get significant vectorization (but you don't -need to specify it for x86-64 as it is part of the base 64-bit architecture). -Similarly, for the PowerPC architecture, you should specify @option{-maltivec}. +@strong{Builder.Global_Configuration_Pragmas}: -The preferred loop form for vectorization is the @code{for} iteration scheme. -Loops with a @code{while} iteration scheme can also be vectorized if they are -very simple, but the vectorizer will quickly give up otherwise. With either -iteration scheme, the flow of control must be straight, in particular no -@code{exit} statement may appear in the loop body. The loop may however -contain a single nested loop, if it can be vectorized when considered alone: +@quotation -@smallexample @c ada -@cartouche - A : @b{array} (1..4, 1..4) @b{of} Long_Float; - S : @b{array} (1..4) @b{of} Long_Float; - - @b{procedure} Sum @b{is} - @b{begin} - @b{for} I @b{in} A'Range(1) @b{loop} - @b{for} J @b{in} A'Range(2) @b{loop} - S (I) := S (I) + A (I, J); - @b{end} @b{loop}; - @b{end} @b{loop}; - @b{end} Sum; -@end cartouche -@end smallexample +This attribute points to a file that contains configuration pragmas +to use when building executables. These pragmas apply for all +executables built from this project hierarchy. As we have seen before, +additional pragmas can be specified on a per-project basis by setting the +@cite{Compiler.Local_Configuration_Pragmas} attribute. +@end quotation -The vectorizable operations depend on the targeted SIMD instruction set, but -the adding and some of the multiplying operators are generally supported, as -well as the logical operators for modular types. Note that, in the former -case, enabling overflow checks, for example with @option{-gnato}, totally -disables vectorization. The other checks are not supposed to have the same -definitive effect, although compiling with @option{-gnatp} might well reveal -cases where some checks do thwart vectorization. +@geindex Global_Compilation_Switches (GNAT Project Manager) -Type conversions may also prevent vectorization if they involve semantics that -are not directly supported by the code generator or the SIMD instruction set. -A typical example is direct conversion from floating-point to integer types. -The solution in this case is to use the following idiom: +@strong{Builder.Global_Compilation_Switches}: -@smallexample @c ada - Integer (S'Truncation (F)) -@end smallexample +@quotation -@noindent -if @code{S} is the subtype of floating-point object @code{F}. +This attribute is a list of compiler switches to use when compiling any +source file in the project hierarchy. These switches are used in addition +to the ones defined in the @cite{Compiler} package, which only apply to +the sources of the corresponding project. This attribute is indexed on +the name of the language. +@end quotation -In most cases, the vectorizable loops are loops that iterate over arrays. -All kinds of array types are supported, i.e. constrained array types with -static bounds: +Using such global capabilities is convenient. It can also lead to unexpected +behavior. Especially when several subsystems are shared among different main +projects and the different global attributes are not +compatible. Note that using aggregate projects can be a safer and more powerful +replacement to global attributes. -@smallexample @c ada - @b{type} Array_Type @b{is} @b{array} (1 .. 4) @b{of} Long_Float; -@end smallexample +@node Scenarios in Projects,Library Projects,Organizing Projects into Subsystems,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager id19}@anchor{176}@anchor{gnat_ugn/gnat_project_manager scenarios-in-projects}@anchor{14c} +@section Scenarios in Projects -@noindent -constrained array types with dynamic bounds: -@smallexample @c ada - @b{type} Array_Type @b{is} @b{array} (1 .. Q.N) @b{of} Long_Float; +Various aspects of the projects can be modified based on @strong{scenarios}. These +are user-defined modes that change the behavior of a project. Typical +examples are the setup of platform-specific compiler options, or the use of +a debug and a release mode (the former would activate the generation of debug +information, while the second will focus on improving code optimization). - @b{type} Array_Type @b{is} @b{array} (Q.K .. 4) @b{of} Long_Float; +Let's enhance our example to support debug and release modes. The issue is to +let the user choose what kind of system he is building: use @emph{-g} as +compiler switches in debug mode and @emph{-O2} in release mode. We will also +set up the projects so that we do not share the same object directory in both +modes; otherwise switching from one to the other might trigger more +recompilations than needed or mix objects from the two modes. - @b{type} Array_Type @b{is} @b{array} (Q.K .. Q.N) @b{of} Long_Float; -@end smallexample +One naive approach is to create two different project files, say +@code{build_debug.gpr} and @code{build_release.gpr}, that set the appropriate +attributes as explained in previous sections. This solution does not scale +well, because in the presence of multiple projects depending on each other, you +will also have to duplicate the complete hierarchy and adapt the project files +to point to the right copies. -@noindent -or unconstrained array types: +@geindex scenarios (GNAT Project Manager) -@smallexample @c ada - @b{type} Array_Type @b{is} @b{array} (Positive @b{range} <>) @b{of} Long_Float; -@end smallexample +Instead, project files support the notion of scenarios controlled +by external values. Such values can come from several sources (in decreasing +order of priority): -@noindent -The quality of the generated code decreases when the dynamic aspect of the -array type increases, the worst code being generated for unconstrained array -types. This is so because, the less information the compiler has about the -bounds of the array, the more fallback code it needs to generate in order to -fix things up at run time. +@geindex -X (usage with GNAT Project Manager) -It is possible to specify that a given loop should be subject to vectorization -preferably to other optimizations by means of pragma @code{Loop_Optimize}: -@smallexample @c ada - @b{pragma} Loop_Optimize (Vector); -@end smallexample +@table @asis -@noindent -placed immediately within the loop will convey the appropriate hint to the -compiler for this loop. +@item @strong{Command line}: -It is also possible to help the compiler generate better vectorized code -for a given loop by asserting that there are no loop-carried dependencies -in the loop. Consider for example the procedure: +When launching @emph{gnatmake} or @emph{gprbuild}, the user can pass +extra @emph{-X} switches to define the external value. In +our case, the command line might look like -@smallexample @c ada - @b{type} Arr @b{is} @b{array} (1 .. 4) @b{of} Long_Float; +@example +gnatmake -Pbuild.gpr -Xmode=debug +@end example - @b{procedure} Add (X, Y : @b{not} @b{null} @b{access} Arr; R : @b{not} @b{null} @b{access} Arr) @b{is} - @b{begin} - @b{for} I @b{in} Arr'Range @b{loop} - R(I) := X(I) + Y(I); - @b{end} @b{loop}; - @b{end}; -@end smallexample +or -@noindent -By default, the compiler cannot unconditionally vectorize the loop because -assigning to a component of the array designated by R in one iteration could -change the value read from the components of the array designated by X or Y -in a later iteration. As a result, the compiler will generate two versions -of the loop in the object code, one vectorized and the other not vectorized, -as well as a test to select the appropriate version at run time. This can -be overcome by another hint: +@example +gnatmake -Pbuild.gpr -Xmode=release +@end example -@smallexample @c ada - @b{pragma} Loop_Optimize (Ivdep); -@end smallexample +@item @strong{Environment variables}: -@noindent -placed immediately within the loop will tell the compiler that it can safely -omit the non-vectorized version of the loop as well as the run-time test. +When the external value does not come from the command line, it can come from +the value of environment variables of the appropriate name. +In our case, if an environment variable called "mode" +exists, its value will be taken into account. +@end table -@node Other Optimization Switches -@subsection Other Optimization Switches -@cindex Optimization Switches +@geindex external (GNAT Project Manager) + +@strong{External function second parameter}. + +We now need to get that value in the project. The general form is to use +the predefined function @strong{external} which returns the current value of +the external. For instance, we could set up the object directory to point to +either @code{obj/debug} or @code{obj/release} by changing our project to + +@example +project Build is + for Object_Dir use "obj/" & external ("mode", "debug"); + ... -- as before +end Build; +@end example + +The second parameter to @cite{external} is optional, and is the default +value to use if "mode" is not set from the command line or the environment. + +In order to set the switches according to the different scenarios, other +constructs have to be introduced such as typed variables and case constructions. + +@geindex typed variable (GNAT Project Manager) + +@geindex case construction (GNAT Project Manager) + +A @strong{typed variable} is a variable that +can take only a limited number of values, similar to an enumeration in Ada. +Such a variable can then be used in a @strong{case construction} and create conditional +sections in the project. The following example shows how this can be done: + +@example +project Build is + type Mode_Type is ("debug", "release"); -- all possible values + Mode : Mode_Type := external ("mode", "debug"); -- a typed variable + + package Compiler is + case Mode is + when "debug" => + for Switches ("Ada") + use ("-g"); + when "release" => + for Switches ("Ada") + use ("-O2"); + end case; + end Compiler; +end Build; +@end example + +The project has suddenly grown in size, but has become much more flexible. +@cite{Mode_Type} defines the only valid values for the @cite{mode} variable. If +any other value is read from the environment, an error is reported and the +project is considered as invalid. + +The @cite{Mode} variable is initialized with an external value +defaulting to @cite{"debug"}. This default could be omitted and that would +force the user to define the value. Finally, we can use a case construction to set the +switches depending on the scenario the user has chosen. + +Most aspects of the projects can depend on scenarios. The notable exception +are project dependencies (@emph{with} clauses), which cannot depend on a scenario. + +Scenarios work the same way with @strong{project hierarchies}: you can either +duplicate a variable similar to @cite{Mode} in each of the project (as long +as the first argument to @cite{external} is always the same and the type is +the same), or simply set the variable in the @code{shared.gpr} project +(see @ref{171,,Sharing Between Projects}). + +@node Library Projects,Project Extension,Scenarios in Projects,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager library-projects}@anchor{8a}@anchor{gnat_ugn/gnat_project_manager id20}@anchor{177} +@section Library Projects + + +So far, we have seen examples of projects that create executables. However, +it is also possible to create libraries instead. A @strong{library} is a specific +type of subsystem where, for convenience, objects are grouped together +using system-specific means such as archives or windows DLLs. + +Library projects provide a system- and language-independent way of building +both @strong{static} and @strong{dynamic} libraries. They also support the concept of +@strong{standalone libraries} (SAL) which offer two significant properties: the +elaboration (e.g. initialization) of the library is either automatic or +very simple; a change in the +implementation part of the library implies minimal post-compilation actions on +the complete system and potentially no action at all for the rest of the +system in the case of dynamic SALs. + +There is a restriction on shared library projects: by default, they are only +allowed to import other shared library projects. They are not allowed to +import non library projects or static library projects. + +The GNAT Project Manager takes complete care of the library build, rebuild and +installation tasks, including recompilation of the source files for which +objects do not exist or are not up to date, assembly of the library archive, and +installation of the library (i.e., copying associated source, object and +@code{ALI} files to the specified location). -Since @code{GNAT} uses the @command{gcc} back end, all the specialized -@command{gcc} optimization switches are potentially usable. These switches -have not been extensively tested with GNAT but can generally be expected -to work. Examples of switches in this category are @option{-funroll-loops} -and the various target-specific @option{-m} options (in particular, it has -been observed that @option{-march=xxx} can significantly improve performance -on appropriate machines). For full details of these switches, see -@ref{Submodel Options,, Hardware Models and Configurations, gcc, Using -the GNU Compiler Collection (GCC)}. +@menu +* Building Libraries:: +* Using Library Projects:: +* Stand-alone Library Projects:: +* Installing a library with project files:: -@node Optimization and Strict Aliasing -@subsection Optimization and Strict Aliasing -@cindex Aliasing -@cindex Strict Aliasing -@cindex No_Strict_Aliasing +@end menu -@noindent -The strong typing capabilities of Ada allow an optimizer to generate -efficient code in situations where other languages would be forced to -make worst case assumptions preventing such optimizations. Consider -the following example: +@node Building Libraries,Using Library Projects,,Library Projects +@anchor{gnat_ugn/gnat_project_manager id21}@anchor{178}@anchor{gnat_ugn/gnat_project_manager building-libraries}@anchor{179} +@subsection Building Libraries -@smallexample @c ada -@cartouche -@b{procedure} R @b{is} - @b{type} Int1 @b{is} @b{new} Integer; - @b{type} Int2 @b{is} @b{new} Integer; - @b{type} Int1A @b{is} @b{access} Int1; - @b{type} Int2A @b{is} @b{access} Int2; - Int1V : Int1A; - Int2V : Int2A; - @dots{} - -@b{begin} - @dots{} - @b{for} J @b{in} Data'Range @b{loop} - @b{if} Data (J) = Int1V.@b{all} @b{then} - Int2V.@b{all} := Int2V.@b{all} + 1; - @b{end} @b{if}; - @b{end} @b{loop}; - @dots{} -@b{end} R; -@end cartouche -@end smallexample - -@noindent -In this example, since the variable @code{Int1V} can only access objects -of type @code{Int1}, and @code{Int2V} can only access objects of type -@code{Int2}, there is no possibility that the assignment to -@code{Int2V.all} affects the value of @code{Int1V.all}. This means that -the compiler optimizer can "know" that the value @code{Int1V.all} is constant -for all iterations of the loop and avoid the extra memory reference -required to dereference it each time through the loop. -This kind of optimization, called strict aliasing analysis, is -triggered by specifying an optimization level of @option{-O2} or -higher or @option{-Os} and allows @code{GNAT} to generate more efficient code -when access values are involved. +Let's enhance our example and transform the @cite{logging} subsystem into a +library. In order to do so, a few changes need to be made to +@code{logging.gpr}. Some attributes need to be defined: at least +@cite{Library_Name} and @cite{Library_Dir}; in addition, some other attributes +can be used to specify specific aspects of the library. For readability, it is +also recommended (although not mandatory), to use the qualifier @cite{library} +in front of the @cite{project} keyword. -However, although this optimization is always correct in terms of -the formal semantics of the Ada Reference Manual, difficulties can -arise if features like @code{Unchecked_Conversion} are used to break -the typing system. Consider the following complete program example: +@geindex Library_Name (GNAT Project Manager) -@smallexample @c ada -@cartouche -@b{package} p1 @b{is} - @b{type} int1 @b{is} @b{new} integer; - @b{type} int2 @b{is} @b{new} integer; - @b{type} a1 @b{is} @b{access} int1; - @b{type} a2 @b{is} @b{access} int2; -@b{end} p1; - -@b{with} p1; @b{use} p1; -@b{package} p2 @b{is} - @b{function} to_a2 (Input : a1) @b{return} a2; -@b{end} p2; - -@b{with} Unchecked_Conversion; -@b{package} @b{body} p2 @b{is} - @b{function} to_a2 (Input : a1) @b{return} a2 @b{is} - @b{function} to_a2u @b{is} - @b{new} Unchecked_Conversion (a1, a2); - @b{begin} - @b{return} to_a2u (Input); - @b{end} to_a2; -@b{end} p2; - -@b{with} p2; @b{use} p2; -@b{with} p1; @b{use} p1; -@b{with} Text_IO; @b{use} Text_IO; -@b{procedure} m @b{is} - v1 : a1 := @b{new} int1; - v2 : a2 := to_a2 (v1); -@b{begin} - v1.@b{all} := 1; - v2.@b{all} := 0; - put_line (int1'image (v1.@b{all})); -@b{end}; -@end cartouche -@end smallexample +@strong{Library_Name}: -@noindent -This program prints out 0 in @option{-O0} or @option{-O1} -mode, but it prints out 1 in @option{-O2} mode. That's -because in strict aliasing mode, the compiler can and -does assume that the assignment to @code{v2.all} could not -affect the value of @code{v1.all}, since different types -are involved. +@quotation -This behavior is not a case of non-conformance with the standard, since -the Ada RM specifies that an unchecked conversion where the resulting -bit pattern is not a correct value of the target type can result in an -abnormal value and attempting to reference an abnormal value makes the -execution of a program erroneous. That's the case here since the result -does not point to an object of type @code{int2}. This means that the -effect is entirely unpredictable. +This attribute is the name of the library to be built. There is no +restriction on the name of a library imposed by the project manager, except +for stand-alone libraries whose names must follow the syntax of Ada +identifiers; however, there may be system-specific restrictions on the name. +In general, it is recommended to stick to alphanumeric characters (and +possibly single underscores) to help portability. +@end quotation -However, although that explanation may satisfy a language -lawyer, in practice an applications programmer expects an -unchecked conversion involving pointers to create true -aliases and the behavior of printing 1 seems plain wrong. -In this case, the strict aliasing optimization is unwelcome. +@geindex Library_Dir (GNAT Project Manager) -Indeed the compiler recognizes this possibility, and the -unchecked conversion generates a warning: +@strong{Library_Dir}: -@smallexample -p2.adb:5:07: warning: possible aliasing problem with type "a2" -p2.adb:5:07: warning: use -fno-strict-aliasing switch for references -p2.adb:5:07: warning: or use "pragma No_Strict_Aliasing (a2);" -@end smallexample +@quotation -@noindent -Unfortunately the problem is recognized when compiling the body of -package @code{p2}, but the actual "bad" code is generated while -compiling the body of @code{m} and this latter compilation does not see -the suspicious @code{Unchecked_Conversion}. +This attribute is the path (absolute or relative) of the directory where +the library is to be installed. In the process of building a library, +the sources are compiled, the object files end up in the explicit or +implicit @cite{Object_Dir} directory. When all sources of a library +are compiled, some of the compilation artifacts, including the library itself, +are copied to the library_dir directory. This directory must exist and be +writable. It must also be different from the object directory so that cleanup +activities in the Library_Dir do not affect recompilation needs. +@end quotation -As implied by the warning message, there are approaches you can use to -avoid the unwanted strict aliasing optimization in a case like this. +Here is the new version of @code{logging.gpr} that makes it a library: -One possibility is to simply avoid the use of @option{-O2}, but -that is a bit drastic, since it throws away a number of useful -optimizations that do not involve strict aliasing assumptions. +@example +library project Logging is -- "library" is optional + for Library_Name use "logging"; -- will create "liblogging.a" on Unix + for Object_Dir use "obj"; + for Library_Dir use "lib"; -- different from object_dir +end Logging; +@end example -A less drastic approach is to compile the program using the -option @option{-fno-strict-aliasing}. Actually it is only the -unit containing the dereferencing of the suspicious pointer -that needs to be compiled. So in this case, if we compile -unit @code{m} with this switch, then we get the expected -value of zero printed. Analyzing which units might need -the switch can be painful, so a more reasonable approach -is to compile the entire program with options @option{-O2} -and @option{-fno-strict-aliasing}. If the performance is -satisfactory with this combination of options, then the -advantage is that the entire issue of possible "wrong" -optimization due to strict aliasing is avoided. +Once the above two attributes are defined, the library project is valid and +is enough for building a library with default characteristics. +Other library-related attributes can be used to change the defaults: -To avoid the use of compiler switches, the configuration -pragma @code{No_Strict_Aliasing} with no parameters may be -used to specify that for all access types, the strict -aliasing optimization should be suppressed. +@geindex Library_Kind (GNAT Project Manager) -However, these approaches are still overkill, in that they causes -all manipulations of all access values to be deoptimized. A more -refined approach is to concentrate attention on the specific -access type identified as problematic. +@strong{Library_Kind}: -First, if a careful analysis of uses of the pointer shows -that there are no possible problematic references, then -the warning can be suppressed by bracketing the -instantiation of @code{Unchecked_Conversion} to turn -the warning off: +@quotation -@smallexample @c ada - @b{pragma} Warnings (Off); - @b{function} to_a2u @b{is} - @b{new} Unchecked_Conversion (a1, a2); - @b{pragma} Warnings (On); -@end smallexample +The value of this attribute must be either @cite{"static"}, @cite{"dynamic"} or +@cite{"relocatable"} (the latter is a synonym for dynamic). It indicates +which kind of library should be built (the default is to build a +static library, that is an archive of object files that can potentially +be linked into a static executable). When the library is set to be dynamic, +a separate image is created that will be loaded independently, usually +at the start of the main program execution. Support for dynamic libraries is +very platform specific, for instance on Windows it takes the form of a DLL +while on GNU/Linux, it is a dynamic elf image whose suffix is usually +@code{.so}. Library project files, on the other hand, can be written in +a platform independent way so that the same project file can be used to build +a library on different operating systems. + +If you need to build both a static and a dynamic library, it is recommended +to use two different object directories, since in some cases some extra code +needs to be generated for the latter. For such cases, one can either define +two different project files, or a single one that uses scenarios to indicate +the various kinds of library to be built and their corresponding object_dir. +@end quotation -@noindent -Of course that approach is not appropriate for this particular -example, since indeed there is a problematic reference. In this -case we can take one of two other approaches. +@geindex Library_ALI_Dir (GNAT Project Manager) -The first possibility is to move the instantiation of unchecked -conversion to the unit in which the type is declared. In -this example, we would move the instantiation of -@code{Unchecked_Conversion} from the body of package -@code{p2} to the spec of package @code{p1}. Now the -warning disappears. That's because any use of the -access type knows there is a suspicious unchecked -conversion, and the strict aliasing optimization -is automatically suppressed for the type. +@strong{Library_ALI_Dir}: -If it is not practical to move the unchecked conversion to the same unit -in which the destination access type is declared (perhaps because the -source type is not visible in that unit), you may use pragma -@code{No_Strict_Aliasing} for the type. This pragma must occur in the -same declarative sequence as the declaration of the access type: +@quotation -@smallexample @c ada - @b{type} a2 @b{is} @b{access} int2; - @b{pragma} No_Strict_Aliasing (a2); -@end smallexample +This attribute may be specified to indicate the directory where the ALI +files of the library are installed. By default, they are copied into the +@cite{Library_Dir} directory, but as for the executables where we have a +separate @cite{Exec_Dir} attribute, you might want to put them in a separate +directory since there can be hundreds of them. The same restrictions as for +the @cite{Library_Dir} attribute apply. +@end quotation -@noindent -Here again, the compiler now knows that the strict aliasing optimization -should be suppressed for any reference to type @code{a2} and the -expected behavior is obtained. +@geindex Library_Version (GNAT Project Manager) -Finally, note that although the compiler can generate warnings for -simple cases of unchecked conversions, there are tricker and more -indirect ways of creating type incorrect aliases which the compiler -cannot detect. Examples are the use of address overlays and unchecked -conversions involving composite types containing access types as -components. In such cases, no warnings are generated, but there can -still be aliasing problems. One safe coding practice is to forbid the -use of address clauses for type overlaying, and to allow unchecked -conversion only for primitive types. This is not really a significant -restriction since any possible desired effect can be achieved by -unchecked conversion of access values. +@strong{Library_Version}: -The aliasing analysis done in strict aliasing mode can certainly -have significant benefits. We have seen cases of large scale -application code where the time is increased by up to 5% by turning -this optimization off. If you have code that includes significant -usage of unchecked conversion, you might want to just stick with -@option{-O1} and avoid the entire issue. If you get adequate -performance at this level of optimization level, that's probably -the safest approach. If tests show that you really need higher -levels of optimization, then you can experiment with @option{-O2} -and @option{-O2 -fno-strict-aliasing} to see how much effect this -has on size and speed of the code. If you really need to use -@option{-O2} with strict aliasing in effect, then you should -review any uses of unchecked conversion of access types, -particularly if you are getting the warnings described above. +@quotation -@node Aliased Variables and Optimization -@subsection Aliased Variables and Optimization -@cindex Aliasing -There are scenarios in which programs may -use low level techniques to modify variables -that otherwise might be considered to be unassigned. For example, -a variable can be passed to a procedure by reference, which takes -the address of the parameter and uses the address to modify the -variable's value, even though it is passed as an IN parameter. -Consider the following example: +This attribute is platform dependent, and has no effect on Windows. +On Unix, it is used only for dynamic libraries as the internal +name of the library (the @cite{"soname"}). If the library file name (built +from the @cite{Library_Name}) is different from the @cite{Library_Version}, +then the library file will be a symbolic link to the actual file whose name +will be @cite{Library_Version}. This follows the usual installation schemes +for dynamic libraries on many Unix systems. + +@example +project Logging is + Version := "1"; + for Library_Dir use "lib"; + for Library_Name use "logging"; + for Library_Kind use "dynamic"; + for Library_Version use "liblogging.so." & Version; +end Logging; +@end example + +After the compilation, the directory @code{lib} will contain both a +@code{libdummy.so.1} library and a symbolic link to it called +@code{libdummy.so}. +@end quotation -@smallexample @c ada -@b{procedure} P @b{is} - Max_Length : @b{constant} Natural := 16; - @b{type} Char_Ptr @b{is} @b{access} @b{all} Character; +@geindex Library_GCC (GNAT Project Manager) - @b{procedure} Get_String(Buffer: Char_Ptr; Size : Integer); - @b{pragma} Import (C, Get_String, "get_string"); +@strong{Library_GCC}: - Name : @b{aliased} String (1 .. Max_Length) := (@b{others} => ' '); - Temp : Char_Ptr; +@quotation - @b{function} Addr (S : String) @b{return} Char_Ptr @b{is} - @b{function} To_Char_Ptr @b{is} - @b{new} Ada.Unchecked_Conversion (System.Address, Char_Ptr); - @b{begin} - @b{return} To_Char_Ptr (S (S'First)'Address); - @b{end}; +This attribute is the name of the tool to use instead of "gcc" to link shared +libraries. A common use of this attribute is to define a wrapper script that +accomplishes specific actions before calling gcc (which itself calls the +linker to build the library image). +@end quotation -@b{begin} - Temp := Addr (Name); - Get_String (Temp, Max_Length); -@b{end}; -@end smallexample +@geindex Library_Options (GNAT Project Manager) -@noindent -where Get_String is a C function that uses the address in Temp to -modify the variable @code{Name}. This code is dubious, and arguably -erroneous, and the compiler would be entitled to assume that -@code{Name} is never modified, and generate code accordingly. +@strong{Library_Options}: -However, in practice, this would cause some existing code that -seems to work with no optimization to start failing at high -levels of optimzization. +@quotation -What the compiler does for such cases is to assume that marking -a variable as aliased indicates that some "funny business" may -be going on. The optimizer recognizes the aliased keyword and -inhibits optimizations that assume the value cannot be assigned. -This means that the above example will in fact "work" reliably, -that is, it will produce the expected results. +This attribute may be used to specify additional switches (last switches) +when linking a shared library. -@node Atomic Variables and Optimization -@subsection Atomic Variables and Optimization -@cindex Atomic -There are two considerations with regard to performance when -atomic variables are used. +It may also be used to add foreign object files to a static library. +Each string in Library_Options is an absolute or relative path of an object +file. When a relative path, it is relative to the object directory. +@end quotation -First, the RM only guarantees that access to atomic variables -be atomic, it has nothing to say about how this is achieved, -though there is a strong implication that this should not be -achieved by explicit locking code. Indeed GNAT will never -generate any locking code for atomic variable access (it will -simply reject any attempt to make a variable or type atomic -if the atomic access cannot be achieved without such locking code). +@geindex Leading_Library_Options (GNAT Project Manager) -That being said, it is important to understand that you cannot -assume that the entire variable will always be accessed. Consider -this example: +@strong{Leading_Library_Options}: -@smallexample @c ada -@b{type} R @b{is} @b{record} - A,B,C,D : Character; -@b{end} @b{record}; -@b{for} R'Size @b{use} 32; -@b{for} R'Alignment @b{use} 4; +@quotation -RV : R; -@b{pragma} Atomic (RV); -X : Character; -... -X := RV.B; -@end smallexample +This attribute, that is taken into account only by @emph{gprbuild}, may be +used to specified leading options (first switches) when linking a shared +library. +@end quotation -@noindent -You cannot assume that the reference to @code{RV.B} -will read the entire 32-bit -variable with a single load instruction. It is perfectly legitimate if -the hardware allows it to do a byte read of just the B field. This read -is still atomic, which is all the RM requires. GNAT can and does take -advantage of this, depending on the architecture and optimization level. -Any assumption to the contrary is non-portable and risky. Even if you -examine the assembly language and see a full 32-bit load, this might -change in a future version of the compiler. +@geindex Linker_Options (GNAT Project Manager) -If your application requires that all accesses to @code{RV} in this -example be full 32-bit loads, you need to make a copy for the access -as in: +@strong{Linker.Linker_Options}: -@smallexample @c ada -@b{declare} - RV_Copy : @b{constant} R := RV; -@b{begin} - X := RV_Copy.B; -@b{end}; -@end smallexample +@quotation +This attribute specifies additional switches to be given to the linker when +linking an executable. It is ignored when defined in the main project and +taken into account in all other projects that are imported directly or +indirectly. These switches complement the @cite{Linker.Switches} +defined in the main project. This is useful when a particular subsystem +depends on an external library: adding this dependency as a +@cite{Linker_Options} in the project of the subsystem is more convenient than +adding it to all the @cite{Linker.Switches} of the main projects that depend +upon this subsystem. +@end quotation -@noindent -Now the reference to RV must read the whole variable. -Actually one can imagine some compiler which figures -out that the whole copy is not required (because only -the B field is actually accessed), but GNAT -certainly won't do that, and we don't know of any -compiler that would not handle this right, and the -above code will in practice work portably across -all architectures (that permit the Atomic declaration). +@node Using Library Projects,Stand-alone Library Projects,Building Libraries,Library Projects +@anchor{gnat_ugn/gnat_project_manager id22}@anchor{17a}@anchor{gnat_ugn/gnat_project_manager using-library-projects}@anchor{17b} +@subsection Using Library Projects + + +When the builder detects that a project file is a library project file, it +recompiles all sources of the project that need recompilation and rebuild the +library if any of the sources have been recompiled. It then groups all object +files into a single file, which is a shared or a static library. This library +can later on be linked with multiple executables. Note that the use +of shard libraries reduces the size of the final executable and can also reduce +the memory footprint at execution time when the library is shared among several +executables. + +It is also possible to build @strong{multi-language libraries}. When using +@emph{gprbuild} as a builder, multi-language library projects allow naturally +the creation of multi-language libraries . @emph{gnatmake}, does not try to +compile non Ada sources. However, when the project is multi-language, it will +automatically link all object files found in the object directory, whether or +not they were compiled from an Ada source file. This specific behavior does not +apply to Ada-only projects which only take into account the objects +corresponding to the sources of the project. + +A non-library project can import a library project. When the builder is invoked +on the former, the library of the latter is only rebuilt when absolutely +necessary. For instance, if a unit of the library is not up-to-date but none of +the executables need this unit, then the unit is not recompiled and the library +is not reassembled. For instance, let's assume in our example that logging has +the following sources: @code{log1.ads}, @code{log1.adb}, @code{log2.ads} and +@code{log2.adb}. If @code{log1.adb} has been modified, then the library +@code{liblogging} will be rebuilt when compiling all the sources of +@cite{Build} only if @code{proc.ads}, @code{pack.ads} or @code{pack.adb} +include a @cite{"with Log1"}. + +To ensure that all the sources in the @cite{Logging} library are +up to date, and that all the sources of @cite{Build} are also up to date, +the following two commands need to be used: + +@example +gnatmake -Plogging.gpr +gnatmake -Pbuild.gpr +@end example + +All @code{ALI} files will also be copied from the object directory to the +library directory. To build executables, @emph{gnatmake} will use the +library rather than the individual object files. + +Library projects can also be useful to describe a library that needs to be used +but, for some reason, cannot be rebuilt. For instance, it is the case when some +of the library sources are not available. Such library projects need to use the +@cite{Externally_Built} attribute as in the example below: + +@c code-block: ada-project +@c +@c library project Extern_Lib is +@c for Languages use ("Ada", "C"); +@c for Source_Dirs use ("lib_src"); +@c for Library_Dir use "lib2"; +@c for Library_Kind use "dynamic"; +@c for Library_Name use "l2"; +@c for Externally_Built use "true"; -- <<<< +@c end Extern_Lib; + +In the case of externally built libraries, the @cite{Object_Dir} +attribute does not need to be specified because it will never be +used. + +The main effect of using such an externally built library project is mostly to +affect the linker command in order to reference the desired library. It can +also be achieved by using @cite{Linker.Linker_Options} or @cite{Linker.Switches} +in the project corresponding to the subsystem needing this external library. +This latter method is more straightforward in simple cases but when several +subsystems depend upon the same external library, finding the proper place +for the @cite{Linker.Linker_Options} might not be easy and if it is +not placed properly, the final link command is likely to present ordering issues. +In such a situation, it is better to use the externally built library project +so that all other subsystems depending on it can declare this dependency thanks +to a project @emph{with} clause, which in turn will trigger the builder to find +the proper order of libraries in the final link command. + +@node Stand-alone Library Projects,Installing a library with project files,Using Library Projects,Library Projects +@anchor{gnat_ugn/gnat_project_manager id23}@anchor{17c}@anchor{gnat_ugn/gnat_project_manager stand-alone-library-projects}@anchor{97} +@subsection Stand-alone Library Projects + + +@geindex standalone libraries (usage with GNAT Project Manager) + +A @strong{stand-alone library} is a library that contains the necessary code to +elaborate the Ada units that are included in the library. A stand-alone +library is a convenient way to add an Ada subsystem to a more global system +whose main is not in Ada since it makes the elaboration of the Ada part mostly +transparent. However, stand-alone libraries are also useful when the main is in +Ada: they provide a means for minimizing relinking & redeployment of complex +systems when localized changes are made. + +The name of a stand-alone library, specified with attribute +@cite{Library_Name}, must have the syntax of an Ada identifier. + +The most prominent characteristic of a stand-alone library is that it offers a +distinction between interface units and implementation units. Only the former +are visible to units outside the library. A stand-alone library project is thus +characterised by a third attribute, usually @strong{Library_Interface}, in addition +to the two attributes that make a project a Library Project +(@cite{Library_Name} and @cite{Library_Dir}). This third attribute may also be +@strong{Interfaces}. @strong{Library_Interface} only works when the interface is in Ada +and takes a list of units as parameter. @strong{Interfaces} works for any supported +language and takes a list of sources as parameter. + +@geindex Library_Interface (GNAT Project Manager) + +@strong{Library_Interface}: -The second issue with atomic variables has to do with -the possible requirement of generating synchronization -code. For more details on this, consult the sections on -the pragmas Enable/Disable_Atomic_Synchronization in the -GNAT Reference Manual. If performance is critical, and -such synchronization code is not required, it may be -useful to disable it. +@quotation -@node Passive Task Optimization -@subsection Passive Task Optimization -@cindex Passive Task +This attribute defines an explicit subset of the units of the project. Units +from projects importing this library project may only "with" units whose +sources are listed in the @cite{Library_Interface}. Other sources are +considered implementation units. -A passive task is one which is sufficiently simple that -in theory a compiler could recognize it an implement it -efficiently without creating a new thread. The original design -of Ada 83 had in mind this kind of passive task optimization, but -only a few Ada 83 compilers attempted it. The problem was that -it was difficult to determine the exact conditions under which -the optimization was possible. The result is a very fragile -optimization where a very minor change in the program can -suddenly silently make a task non-optimizable. +@example +for Library_Dir use "lib"; +for Library_Name use "logging"; +for Library_Interface use ("lib1", "lib2"); -- unit names +@end example +@end quotation -With the revisiting of this issue in Ada 95, there was general -agreement that this approach was fundamentally flawed, and the -notion of protected types was introduced. When using protected -types, the restrictions are well defined, and you KNOW that the -operations will be optimized, and furthermore this optimized -performance is fully portable. +@strong{Interfaces} -Although it would theoretically be possible for GNAT to attempt to -do this optimization, but it really doesn't make sense in the -context of Ada 95, and none of the Ada 95 compilers implement -this optimization as far as we know. In particular GNAT never -attempts to perform this optimization. +@quotation -In any new Ada 95 code that is written, you should always -use protected types in place of tasks that might be able to -be optimized in this manner. -Of course this does not help if you have legacy Ada 83 code -that depends on this optimization, but it is unusual to encounter -a case where the performance gains from this optimization -are significant. +This attribute defines an explicit subset of the source files of a project. +Sources from projects importing this project, can only depend on sources from +this subset. This attribute can be used on non library projects. It can also +be used as a replacement for attribute @cite{Library_Interface}, in which +case, units have to be replaced by source files. For multi-language library +projects, it is the only way to make the project a Stand-Alone Library project +whose interface is not purely Ada. +@end quotation -Your program should work correctly without this optimization. If -you have performance problems, then the most practical -approach is to figure out exactly where these performance problems -arise, and update those particular tasks to be protected types. Note -that typically clients of the tasks who call entries, will not have -to be modified, only the task definition itself. +@geindex Library_Standalone (GNAT Project Manager) + +@strong{Library_Standalone}: + +@quotation +This attribute defines the kind of standalone library to +build. Values are either @cite{standard} (the default), @cite{no} or +@cite{encapsulated}. When @cite{standard} is used the code to elaborate and +finalize the library is embedded, when @cite{encapsulated} is used the +library can furthermore depend only on static libraries (including +the GNAT runtime). This attribute can be set to @cite{no} to make it clear +that the library should not be standalone in which case the +@cite{Library_Interface} should not defined. Note that this attribute +only applies to shared libraries, so @cite{Library_Kind} must be set +to @cite{dynamic}. + +@example +for Library_Dir use "lib"; +for Library_Name use "logging"; +for Library_Kind use "dynamic"; +for Library_Interface use ("lib1", "lib2"); -- unit names +for Library_Standalone use "encapsulated"; +@end example +@end quotation +In order to include the elaboration code in the stand-alone library, the binder +is invoked on the closure of the library units creating a package whose name +depends on the library name (b~logging.ads/b in the example). +This binder-generated package includes @strong{initialization} and @strong{finalization} +procedures whose names depend on the library name (@cite{logginginit} and +@cite{loggingfinal} in the example). The object corresponding to this package is +included in the library. -@node Text_IO Suggestions -@section @code{Text_IO} Suggestions -@cindex @code{Text_IO} and performance +@geindex Library_Auto_Init (GNAT Project Manager) -@noindent -The @code{Ada.Text_IO} package has fairly high overheads due in part to -the requirement of maintaining page and line counts. If performance -is critical, a recommendation is to use @code{Stream_IO} instead of -@code{Text_IO} for volume output, since this package has less overhead. +@strong{Library_Auto_Init}: -If @code{Text_IO} must be used, note that by default output to the standard -output and standard error files is unbuffered (this provides better -behavior when output statements are used for debugging, or if the -progress of a program is observed by tracking the output, e.g. by -using the Unix @command{tail -f} command to watch redirected output. +@quotation -If you are generating large volumes of output with @code{Text_IO} and -performance is an important factor, use a designated file instead -of the standard output file, or change the standard output file to -be buffered using @code{Interfaces.C_Streams.setvbuf}. +A dynamic stand-alone Library is automatically initialized +if automatic initialization of Stand-alone Libraries is supported on the +platform and if attribute @strong{Library_Auto_Init} is not specified or +is specified with the value "true". A static Stand-alone Library is never +automatically initialized. Specifying "false" for this attribute +prevents automatic initialization. + +When a non-automatically initialized stand-alone library is used in an +executable, its initialization procedure must be called before any service of +the library is used. When the main subprogram is in Ada, it may mean that the +initialization procedure has to be called during elaboration of another +package. +@end quotation +@geindex Library_Dir (GNAT Project Manager) -@ifclear FSFEDITION -@node Reducing Size of Ada Executables with gnatelim -@section Reducing Size of Ada Executables with @code{gnatelim} -@findex gnatelim +@strong{Library_Dir}: -@noindent -This section describes @command{gnatelim}, a tool which detects unused -subprograms and helps the compiler to create a smaller executable for your -program. +@quotation + +For a stand-alone library, only the @code{ALI} files of the interface units +(those that are listed in attribute @cite{Library_Interface}) are copied to +the library directory. As a consequence, only the interface units may be +imported from Ada units outside of the library. If other units are imported, +the binding phase will fail. +@end quotation + +@strong{Binder.Default_Switches}: + +@quotation + +When a stand-alone library is bound, the switches that are specified in +the attribute @strong{Binder.Default_Switches ("Ada")} are +used in the call to @emph{gnatbind}. +@end quotation + +@geindex Library_Src_Dir (GNAT Project Manager) + +@strong{Library_Src_Dir}: + +@quotation + +This attribute defines the location (absolute or relative to the project +directory) where the sources of the interface units are copied at +installation time. +These sources includes the specs of the interface units along with the +closure of sources necessary to compile them successfully. That may include +bodies and subunits, when pragmas @cite{Inline} are used, or when there are +generic units in specs. This directory cannot point to the object directory +or one of the source directories, but it can point to the library directory, +which is the default value for this attribute. +@end quotation + +@geindex Library_Symbol_Policy (GNAT Project Manager) + +@strong{Library_Symbol_Policy}: + +@quotation + +This attribute controls the export of symbols and, on some platforms (like +VMS) that have the notions of major and minor IDs built in the library +files, it controls the setting of these IDs. It is not supported on all +platforms (where it will just have no effect). It may have one of the +following values: + + +@itemize * + +@item +@cite{"autonomous"} or @cite{"default"}: exported symbols are not controlled + +@item +@cite{"compliant"}: if attribute @strong{Library_Reference_Symbol_File} +is not defined, then it is equivalent to policy "autonomous". If there +are exported symbols in the reference symbol file that are not in the +object files of the interfaces, the major ID of the library is increased. +If there are symbols in the object files of the interfaces that are not +in the reference symbol file, these symbols are put at the end of the list +in the newly created symbol file and the minor ID is increased. + +@item +@cite{"controlled"}: the attribute @strong{Library_Reference_Symbol_File} must be +defined. The library will fail to build if the exported symbols in the +object files of the interfaces do not match exactly the symbol in the +symbol file. + +@item +@cite{"restricted"}: The attribute @strong{Library_Symbol_File} must be defined. +The library will fail to build if there are symbols in the symbol file that +are not in the exported symbols of the object files of the interfaces. +Additional symbols in the object files are not added to the symbol file. + +@item +@cite{"direct"}: The attribute @strong{Library_Symbol_File} must be defined and +must designate an existing file in the object directory. This symbol file +is passed directly to the underlying linker without any symbol processing. +@end itemize +@end quotation + +@geindex Library_Reference_Symbol_File (GNAT Project Manager) + +@strong{Library_Reference_Symbol_File} + +@quotation + +This attribute may define the path name of a reference symbol file that is +read when the symbol policy is either "compliant" or "controlled", on +platforms that support symbol control, such as VMS, when building a +stand-alone library. The path may be an absolute path or a path relative +to the project directory. +@end quotation + +@geindex Library_Symbol_File (GNAT Project Manager) + +@strong{Library_Symbol_File} + +@quotation + +This attribute may define the name of the symbol file to be created when +building a stand-alone library when the symbol policy is either "compliant", +"controlled" or "restricted", on platforms that support symbol control, +such as VMS. When symbol policy is "direct", then a file with this name +must exist in the object directory. +@end quotation + +@node Installing a library with project files,,Stand-alone Library Projects,Library Projects +@anchor{gnat_ugn/gnat_project_manager installing-a-library-with-project-files}@anchor{8d}@anchor{gnat_ugn/gnat_project_manager id24}@anchor{17d} +@subsection Installing a library with project files + + +When using project files, a usable version of the library is created in the +directory specified by the @cite{Library_Dir} attribute of the library +project file. Thus no further action is needed in order to make use of +the libraries that are built as part of the general application build. + +You may want to install a library in a context different from where the library +is built. This situation arises with third party suppliers, who may want +to distribute a library in binary form where the user is not expected to be +able to recompile the library. The simplest option in this case is to provide +a project file slightly different from the one used to build the library, by +using the @cite{externally_built} attribute. See @ref{17b,,Using Library Projects} + +Another option is to use @emph{gprinstall} to install the library in a +different context than the build location. @emph{gprinstall} automatically +generates a project to use this library, and also copies the minimum set of +sources needed to use the library to the install location. +@ref{168,,Installation} + +@node Project Extension,Aggregate Projects,Library Projects,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager id25}@anchor{17e}@anchor{gnat_ugn/gnat_project_manager project-extension}@anchor{14f} +@section Project Extension + + +During development of a large system, it is sometimes necessary to use +modified versions of some of the source files, without changing the original +sources. This can be achieved through the @strong{project extension} facility. + +Suppose for instance that our example @cite{Build} project is built every night +for the whole team, in some shared directory. A developer usually needs to work +on a small part of the system, and might not want to have a copy of all the +sources and all the object files (mostly because that would require too much +disk space, time to recompile everything). He prefers to be able to override +some of the source files in his directory, while taking advantage of all the +object files generated at night. + +Another example can be taken from large software systems, where it is common to have +multiple implementations of a common interface; in Ada terms, multiple +versions of a package body for the same spec. For example, one implementation +might be safe for use in tasking programs, while another might be used only +in sequential applications. This can be modeled in GNAT using the concept +of @emph{project extension}. If one project (the 'child') @emph{extends} +another project (the 'parent') then by default all source files of the +parent project are inherited by the child, but the child project can +override any of the parent's source files with new versions, and can also +add new files or remove unnecessary ones. +This facility is the project analog of a type extension in +object-oriented programming. Project hierarchies are permitted (an extending +project may itself be extended), and a project that +extends a project can also import other projects. + +A third example is that of using project extensions to provide different +versions of the same system. For instance, assume that a @cite{Common} +project is used by two development branches. One of the branches has now +been frozen, and no further change can be done to it or to @cite{Common}. +However, the other development branch still needs evolution of @cite{Common}. +Project extensions provide a flexible solution to create a new version +of a subsystem while sharing and reusing as much as possible from the original +one. + +A project extension implicitly inherits all the sources and objects from the +project it extends. It is possible to create a new version of some of the +sources in one of the additional source directories of the extending +project. Those new versions hide the original versions. Adding new sources or +removing existing ones is also possible. Here is an example on how to extend +the project @cite{Build} from previous examples: + +@example +project Work extends "../bld/build.gpr" is +end Work; +@end example + +The project after @strong{extends} is the one being extended. As usual, it can be +specified using an absolute path, or a path relative to any of the directories +in the project path (see @ref{16c,,Project Dependencies}). This project does not +specify source or object directories, so the default values for these +attributes will be used that is to say the current directory (where project +@cite{Work} is placed). We can compile that project with + +@example +gprbuild -Pwork +@end example + +If no sources have been placed in the current directory, this command +won't do anything, since this project does not change the +sources it inherited from @cite{Build}, therefore all the object files +in @cite{Build} and its dependencies are still valid and are reused +automatically. + +Suppose we now want to supply an alternate version of @code{pack.adb} but use +the existing versions of @code{pack.ads} and @code{proc.adb}. We can create +the new file in Work's current directory (likely by copying the one from the +@cite{Build} project and making changes to it. If new packages are needed at +the same time, we simply create new files in the source directory of the +extending project. + +When we recompile, @emph{gprbuild} will now automatically recompile +this file (thus creating @code{pack.o} in the current directory) and +any file that depends on it (thus creating @code{proc.o}). Finally, the +executable is also linked locally. + +Note that we could have obtained the desired behavior using project import +rather than project inheritance. A @cite{base} project would contain the +sources for @code{pack.ads} and @code{proc.adb}, and @cite{Work} would +import @cite{base} and add @code{pack.adb}. In this scenario, @cite{base} +cannot contain the original version of @code{pack.adb} otherwise there would be +2 versions of the same unit in the closure of the project and this is not +allowed. Generally speaking, it is not recommended to put the spec and the +body of a unit in different projects since this affects their autonomy and +reusability. + +In a project file that extends another project, it is possible to +indicate that an inherited source is @strong{not part} of the sources of the +extending project. This is necessary sometimes when a package spec has +been overridden and no longer requires a body: in this case, it is +necessary to indicate that the inherited body is not part of the sources +of the project, otherwise there will be a compilation error +when compiling the spec. + +@geindex Excluded_Source_Files (GNAT Project Manager) + +@geindex Excluded_Source_List_File (GNAT Project Manager) + +For that purpose, the attribute @strong{Excluded_Source_Files} is used. +Its value is a list of file names. +It is also possible to use attribute @cite{Excluded_Source_List_File}. +Its value is the path of a text file containing one file name per +line. + +@example +project Work extends "../bld/build.gpr" is + for Source_Files use ("pack.ads"); + -- New spec of Pkg does not need a completion + for Excluded_Source_Files use ("pack.adb"); +end Work; +@end example + +All packages that are not declared in the extending project are inherited from +the project being extended, with their attributes, with the exception of +@cite{Linker'Linker_Options} which is never inherited. In particular, an +extending project retains all the switches specified in the project being +extended. + +At the project level, if they are not declared in the extending project, some +attributes are inherited from the project being extended. They are: +@cite{Languages}, @cite{Main} (for a root non library project) and +@cite{Library_Name} (for a project extending a library project). @menu -* About gnatelim:: -* Running gnatelim:: -* Processing Precompiled Libraries:: -* Correcting the List of Eliminate Pragmas:: -* Making Your Executables Smaller:: -* Summary of the gnatelim Usage Cycle:: +* Project Hierarchy Extension:: + @end menu -@node About gnatelim -@subsection About @code{gnatelim} - -@noindent -When a program shares a set of Ada -packages with other programs, it may happen that this program uses -only a fraction of the subprograms defined in these packages. The code -created for these unused subprograms increases the size of the executable. - -@code{gnatelim} tracks unused subprograms in an Ada program and -outputs a list of GNAT-specific pragmas @code{Eliminate} marking all the -subprograms that are declared but never called. By placing the list of -@code{Eliminate} pragmas in the GNAT configuration file @file{gnat.adc} and -recompiling your program, you may decrease the size of its executable, -because the compiler will not generate the code for 'eliminated' subprograms. -@xref{Pragma Eliminate,,, gnat_rm, GNAT Reference Manual}, for more -information about this pragma. - -@code{gnatelim} needs as its input data the name of the main subprogram. - -If a set of source files is specified as @code{gnatelim} arguments, it -treats these files as a complete set of sources making up a program to -analyse, and analyses only these sources. - -After a full successful build of the main subprogram @code{gnatelim} can be -called without specifying sources to analyse, in this case it computes -the source closure of the main unit from the @file{ALI} files. - -If the set of sources to be processed by @code{gnatelim} contains sources with -preprocessing directives -then the needed options should be provided to run preprocessor as a part of -the @command{gnatelim} call, and the generated set of pragmas @code{Eliminate} -will correspond to preprocessed sources. - -The following command will create the set of @file{ALI} files needed for -@code{gnatelim}: - -@smallexample -$ gnatmake -c Main_Prog -@end smallexample - -Note that @code{gnatelim} does not need object files. - -@node Running gnatelim -@subsection Running @code{gnatelim} - -@noindent -@code{gnatelim} has the following command-line interface: - -@smallexample -$ gnatelim [@var{switches}] -main=@var{main_unit_name} @{@var{filename}@} @r{[}-cargs @var{gcc_switches}@r{]} -@end smallexample - -@noindent -@var{main_unit_name} should be a name of a source file that contains the main -subprogram of a program (partition). - -Each @var{filename} is the name (including the extension) of a source -file to process. ``Wildcards'' are allowed, and -the file name may contain path information. - -@samp{@var{gcc_switches}} is a list of switches for -@command{gcc}. They will be passed on to all compiler invocations made by -@command{gnatelim} to generate the ASIS trees. Here you can provide -@option{-I} switches to form the source search path, -use the @option{-gnatec} switch to set the configuration file, -use the @option{-gnat05} switch if sources should be compiled in -Ada 2005 mode etc. - -@code{gnatelim} has the following switches: - -@table @option -@c !sort! -@item --version -@cindex @option{--version} @command{gnatelim} -Display Copyright and version, then exit disregarding all other options. +@node Project Hierarchy Extension,,,Project Extension +@anchor{gnat_ugn/gnat_project_manager project-hierarchy-extension}@anchor{17f}@anchor{gnat_ugn/gnat_project_manager id26}@anchor{180} +@subsection Project Hierarchy Extension -@item --help -@cindex @option{--help} @command{gnatelim} -Display usage, then exit disregarding all other options. -@item -P @var{file} -@cindex @option{-P} @command{gnatelim} -Indicates the name of the project file that describes the set of sources -to be processed. +One of the fundamental restrictions in project extension is the following: +@strong{A project is not allowed to import directly or indirectly at the same time an extending project and one of its ancestors}. -@item -X@var{name}=@var{value} -@cindex @option{-X} @command{gnatelim} -Indicates that external variable @var{name} in the argument project -has the value @var{value}. Has no effect if no project is specified as -tool argument. +For example, consider the following hierarchy of projects. -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gnatelim}) -Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). - -@item -files=@var{filename} -@cindex @option{-files} (@code{gnatelim}) -Take the argument source files from the specified file. This file should be an -ordinary text file containing file names separated by spaces or -line breaks. You can use this switch more than once in the same call to -@command{gnatelim}. You also can combine this switch with -an explicit list of files. - -@item -log -@cindex @option{-log} (@command{gnatelim}) -Duplicate all the output sent to @file{stderr} into a log file. The log file -is named @file{gnatelim.log} and is located in the current directory. - -@ignore -@item -log=@var{filename} -@cindex @option{-log} (@command{gnatelim}) -Duplicate all the output sent to @file{stderr} into a specified log file. -@end ignore - -@cindex @option{--no-elim-dispatch} (@command{gnatelim}) -@item --no-elim-dispatch -Do not generate pragmas for dispatching operations. - -@item --ignore=@var{filename} -@cindex @option{--ignore} (@command{gnatelim}) -Do not generate pragmas for subprograms declared in the sources -listed in a specified file - -@cindex @option{-o} (@command{gnatelim}) -@item -o=@var{report_file} -Put @command{gnatelim} output into a specified file. If this file already exists, -it is overridden. If this switch is not used, @command{gnatelim} outputs its results -into @file{stderr} - -@item -j@var{n} -@cindex @option{-j} (@command{gnatelim}) -Use @var{n} processes to carry out the tree creations (internal representations -of the argument sources). On a multiprocessor machine this speeds up processing -of big sets of argument sources. If @var{n} is 0, then the maximum number of -parallel tree creations is the number of core processors on the platform. - -@item -q -@cindex @option{-q} (@command{gnatelim}) -Quiet mode: by default @code{gnatelim} outputs to the standard error -stream the number of program units left to be processed. This option turns -this trace off. - -@cindex @option{-t} (@command{gnatelim}) -@item -t -Print out execution time. - -@item -v -@cindex @option{-v} (@command{gnatelim}) -Verbose mode: @code{gnatelim} version information is printed as Ada -comments to the standard output stream. Also, in addition to the number of -program units left @code{gnatelim} will output the name of the current unit -being processed. - -@item -wq -@cindex @option{-wq} (@command{gnatelim}) -Quiet warning mode - some warnings are suppressed. In particular warnings that -indicate that the analysed set of sources is incomplete to make up a -partition and that some subprogram bodies are missing are not generated. -@end table - -@noindent -Note: to invoke @command{gnatelim} with a project file, use the @code{gnat} -driver (see @ref{The GNAT Driver and Project Files}). - -@node Processing Precompiled Libraries -@subsection Processing Precompiled Libraries - -@noindent -If some program uses a precompiled Ada library, it can be processed by -@code{gnatelim} in a usual way. @code{gnatelim} will newer generate an -Eliminate pragma for a subprogram if the body of this subprogram has not -been analysed, this is a typical case for subprograms from precompiled -libraries. Switch @option{-wq} may be used to suppress -warnings about missing source files and non-analyzed subprogram bodies -that can be generated when processing precompiled Ada libraries. - -@node Correcting the List of Eliminate Pragmas -@subsection Correcting the List of Eliminate Pragmas - -@noindent -In some rare cases @code{gnatelim} may try to eliminate -subprograms that are actually called in the program. In this case, the -compiler will generate an error message of the form: - -@smallexample -main.adb:4:08: cannot reference subprogram "P" eliminated at elim.out:5 -@end smallexample - -@noindent -You will need to manually remove the wrong @code{Eliminate} pragmas from -the configuration file indicated in the error message. You should recompile -your program from scratch after that, because you need a consistent -configuration file(s) during the entire compilation. - -@node Making Your Executables Smaller -@subsection Making Your Executables Smaller - -@noindent -In order to get a smaller executable for your program you now have to -recompile the program completely with the configuration file containing -pragmas Eliminate generated by gnatelim. If these pragmas are placed in -@file{gnat.adc} file located in your current directory, just do: - -@smallexample -$ gnatmake -f main_prog -@end smallexample - -@noindent -(Use the @option{-f} option for @command{gnatmake} to -recompile everything -with the set of pragmas @code{Eliminate} that you have obtained with -@command{gnatelim}). - -Be aware that the set of @code{Eliminate} pragmas is specific to each -program. It is not recommended to merge sets of @code{Eliminate} -pragmas created for different programs in one configuration file. - -@node Summary of the gnatelim Usage Cycle -@subsection Summary of the @code{gnatelim} Usage Cycle - -@noindent -Here is a quick summary of the steps to be taken in order to reduce -the size of your executables with @code{gnatelim}. You may use -other GNAT options to control the optimization level, -to produce the debugging information, to set search path, etc. - -@enumerate -@item -Create a complete set of @file{ALI} files (if the program has not been -built already) +@example +a.gpr contains package A1 +b.gpr, imports a.gpr and contains B1, which depends on A1 +c.gpr, imports b.gpr and contains C1, which depends on B1 +@end example -@smallexample -$ gnatmake -c main_prog -@end smallexample +If we want to locally extend the packages @cite{A1} and @cite{C1}, we need to +create several extending projects: -@item -Generate a list of @code{Eliminate} pragmas in default configuration file -@file{gnat.adc} in the current directory -@smallexample -$ gnatelim main_prog >@r{[}>@r{]} gnat.adc -@end smallexample +@example +a_ext.gpr which extends a.gpr, and overrides A1 +b_ext.gpr which extends b.gpr and imports a_ext.gpr +c_ext.gpr which extends c.gpr, imports b_ext.gpr and overrides C1 +@end example -@item -Recompile the application +@example +project A_Ext extends "a.gpr" is + for Source_Files use ("a1.adb", "a1.ads"); +end A_Ext; -@smallexample -$ gnatmake -f main_prog -@end smallexample +with "a_ext.gpr"; +project B_Ext extends "b.gpr" is +end B_Ext; -@end enumerate -@end ifclear +with "b_ext.gpr"; +project C_Ext extends "c.gpr" is + for Source_Files use ("c1.adb"); +end C_Ext; +@end example -@node Reducing Size of Executables with unused subprogram/data elimination -@section Reducing Size of Executables with Unused Subprogram/Data Elimination -@findex unused subprogram/data elimination +The extension @code{b_ext.gpr} is required, even though we are not overriding +any of the sources of @code{b.gpr} because otherwise @code{c_expr.gpr} would +import @code{b.gpr} which itself knows nothing about @code{a_ext.gpr}. -@noindent -This section describes how you can eliminate unused subprograms and data from -your executable just by setting options at compilation time. +@geindex extends all (GNAT Project Manager) + +When extending a large system spanning multiple projects, it is often +inconvenient to extend every project in the hierarchy that is impacted by a +small change introduced in a low layer. In such cases, it is possible to create +an @strong{implicit extension} of an entire hierarchy using @strong{extends all} +relationship. + +When the project is extended using @cite{extends all} inheritance, all projects +that are imported by it, both directly and indirectly, are considered virtually +extended. That is, the project manager creates implicit projects +that extend every project in the hierarchy; all these implicit projects do not +control sources on their own and use the object directory of +the "extending all" project. + +It is possible to explicitly extend one or more projects in the hierarchy +in order to modify the sources. These extending projects must be imported by +the "extending all" project, which will replace the corresponding virtual +projects with the explicit ones. + +When building such a project hierarchy extension, the project manager will +ensure that both modified sources and sources in implicit extending projects +that depend on them are recompiled. + +Thus, in our example we could create the following projects instead: + +@example +a_ext.gpr, extends a.gpr and overrides A1 +c_ext.gpr, "extends all" c.gpr, imports a_ext.gpr and overrides C1 +@end example + +@example +project A_Ext extends "a.gpr" is + for Source_Files use ("a1.adb", "a1.ads"); +end A_Ext; + +with "a_ext.gpr"; +project C_Ext extends all "c.gpr" is + for Source_Files use ("c1.adb"); +end C_Ext; +@end example + +When building project @code{c_ext.gpr}, the entire modified project space is +considered for recompilation, including the sources of @code{b.gpr} that are +impacted by the changes in @cite{A1} and @cite{C1}. + +@node Aggregate Projects,Aggregate Library Projects,Project Extension,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager aggregate-projects}@anchor{16e}@anchor{gnat_ugn/gnat_project_manager id27}@anchor{181} +@section Aggregate Projects + + +Aggregate projects are an extension of the project paradigm, and are +meant to solve a few specific use cases that cannot be solved directly +using standard projects. This section will go over a few of these use +cases to try to explain what you can use aggregate projects for. @menu -* About unused subprogram/data elimination:: -* Compilation options:: -* Example of unused subprogram/data elimination:: +* Building all main programs from a single project tree:: +* Building a set of projects with a single command:: +* Define a build environment:: +* Performance improvements in builder:: +* Syntax of aggregate projects:: +* package Builder in aggregate projects:: + @end menu -@node About unused subprogram/data elimination -@subsection About unused subprogram/data elimination +@node Building all main programs from a single project tree,Building a set of projects with a single command,,Aggregate Projects +@anchor{gnat_ugn/gnat_project_manager id28}@anchor{182}@anchor{gnat_ugn/gnat_project_manager building-all-main-programs-from-a-single-project-tree}@anchor{183} +@subsection Building all main programs from a single project tree -@noindent -By default, an executable contains all code and data of its composing objects -(directly linked or coming from statically linked libraries), even data or code -never used by this executable. -This feature will allow you to eliminate such unused code from your -executable, making it smaller (in disk and in memory). +Most often, an application is organized into modules and submodules, +which are very conveniently represented as a project tree or graph +(the root project A @emph{with}s the projects for each modules (say B and C), +which in turn @emph{with} projects for submodules. -This functionality is available on all Linux platforms except for the IA-64 -architecture and on all cross platforms using the ELF binary file format. -In both cases GNU binutils version 2.16 or later are required to enable it. +Very often, modules will build their own executables (for testing +purposes for instance), or libraries (for easier reuse in various +contexts). -@node Compilation options -@subsection Compilation options +However, if you build your project through @emph{gnatmake} or +@emph{gprbuild}, using a syntax similar to + +@example +gprbuild -PA.gpr +@end example + +this will only rebuild the main programs of project A, not those of the +imported projects B and C. Therefore you have to spawn several +@emph{gnatmake} commands, one per project, to build all executables. +This is a little inconvenient, but more importantly is inefficient +because @emph{gnatmake} needs to do duplicate work to ensure that sources are +up-to-date, and cannot easily compile things in parallel when using +the -j switch. + +Also libraries are always rebuilt when building a project. + +You could therefore define an aggregate project Agg that groups A, B +and C. Then, when you build with + +@example +gprbuild -PAgg.gpr +@end example + +this will build all mains from A, B and C. + +@example +aggregate project Agg is + for Project_Files use ("a.gpr", "b.gpr", "c.gpr"); +end Agg; +@end example + +If B or C do not define any main program (through their Main +attribute), all their sources are built. When you do not group them +in the aggregate project, only those sources that are needed by A +will be built. + +If you add a main to a project P not already explicitly referenced in the +aggregate project, you will need to add "p.gpr" in the list of project +files for the aggregate project, or the main will not be built when +building the aggregate project. + +Aggregate projects are supported only with @emph{gprbuild}, not with +@emph{gnatmake}. + +@node Building a set of projects with a single command,Define a build environment,Building all main programs from a single project tree,Aggregate Projects +@anchor{gnat_ugn/gnat_project_manager building-a-set-of-projects-with-a-single-command}@anchor{184}@anchor{gnat_ugn/gnat_project_manager id29}@anchor{185} +@subsection Building a set of projects with a single command + + +One other case is when you have multiple applications and libraries +that are built independently from each other (but can be built in +parallel). For instance, you have a project tree rooted at A, and +another one (which might share some subprojects) rooted at B. + +Using only @emph{gprbuild}, you could do + +@example +gprbuild -PA.gpr +gprbuild -PB.gpr +@end example + +to build both. But again, @emph{gprbuild} has to do some duplicate work for +those files that are shared between the two, and cannot truly build +things in parallel efficiently. + +If the two projects are really independent, share no sources other +than through a common subproject, and have no source files with a +common basename, you could create a project C that imports A and +B. But these restrictions are often too strong, and one has to build +them independently. An aggregate project does not have these +limitations and can aggregate two project trees that have common +sources. + +This scenario is particularly useful in environments like VxWorks 653 +where the applications running in the multiple partitions can be built +in parallel through a single @emph{gprbuild} command. This also works nicely +with Annex E. + +@node Define a build environment,Performance improvements in builder,Building a set of projects with a single command,Aggregate Projects +@anchor{gnat_ugn/gnat_project_manager id30}@anchor{186}@anchor{gnat_ugn/gnat_project_manager define-a-build-environment}@anchor{187} +@subsection Define a build environment + + +The environment variables at the time you launch @emph{gprbuild} +will influence the view these tools have of the project +(PATH to find the compiler, ADA_PROJECT_PATH or GPR_PROJECT_PATH to find the +projects, environment variables that are referenced in project files +through the "external" built-in function, ...). Several command line switches +can be used to override those (-X or -aP), but on some systems and +with some projects, this might make the command line too long, and on +all systems often make it hard to read. + +An aggregate project can be used to set the environment for all +projects built through that aggregate. One of the nice aspects is that +you can put the aggregate project under configuration management, and +make sure all your user have a consistent environment when +building. The syntax looks like + +@example +aggregate project Agg is + for Project_Files use ("A.gpr", "B.gpr"); + for Project_Path use ("../dir1", "../dir1/dir2"); + for External ("BUILD") use "PRODUCTION"; + + package Builder is + for Switches ("Ada") use ("-q"); + end Builder; +end Agg; +@end example + +One of the often requested features in projects is to be able to +reference external variables in @emph{with} declarations, as in + +@example +with external("SETUP") & "path/prj.gpr"; -- ILLEGAL +project MyProject is + ... +end MyProject; +@end example -@noindent -The operation of eliminating the unused code and data from the final executable -is directly performed by the linker. +For various reasons, this is not allowed. But using aggregate projects provide +an elegant solution. For instance, you could use a project file like: -In order to do this, it has to work with objects compiled with the -following options: -@option{-ffunction-sections} @option{-fdata-sections}. -@cindex @option{-ffunction-sections} (@command{gcc}) -@cindex @option{-fdata-sections} (@command{gcc}) -These options are usable with C and Ada files. -They will place respectively each -function or data in a separate section in the resulting object file. +@example +aggregate project Agg is + for Project_Path use (external("SETUP") & "path"); + for Project_Files use ("myproject.gpr"); +end Agg; -Once the objects and static libraries are created with these options, the -linker can perform the dead code elimination. You can do this by setting -the @option{-Wl,--gc-sections} option to gcc command or in the -@option{-largs} section of @command{gnatmake}. This will perform a -garbage collection of code and data never referenced. +with "prj.gpr"; -- searched on Agg'Project_Path +project MyProject is + ... +end MyProject; +@end example -If the linker performs a partial link (@option{-r} linker option), then you -will need to provide the entry point using the @option{-e} / @option{--entry} -linker option. +@node Performance improvements in builder,Syntax of aggregate projects,Define a build environment,Aggregate Projects +@anchor{gnat_ugn/gnat_project_manager performance-improvements-in-builder}@anchor{188}@anchor{gnat_ugn/gnat_project_manager id31}@anchor{189} +@subsection Performance improvements in builder -Note that objects compiled without the @option{-ffunction-sections} and -@option{-fdata-sections} options can still be linked with the executable. -However, no dead code elimination will be performed on those objects (they will -be linked as is). -The GNAT static library is now compiled with -ffunction-sections and --fdata-sections on some platforms. This allows you to eliminate the unused code -and data of the GNAT library from your executable. +The loading of aggregate projects is optimized in @emph{gprbuild}, +so that all files are searched for only once on the disk +(thus reducing the number of system calls and contributing to faster +compilation times, especially on systems with sources on remote +servers). As part of the loading, @emph{gprbuild} +computes how and where a source file should be compiled, and even if it is +found several times in the aggregated projects it will be compiled only +once. -@node Example of unused subprogram/data elimination -@subsection Example of unused subprogram/data elimination +Since there is no ambiguity as to which switches should be used, files +can be compiled in parallel (through the usual -j switch) and this can +be done while maximizing the use of CPUs (compared to launching +multiple @emph{gprbuild} and @emph{gnatmake} commands in parallel). -@noindent -Here is a simple example: +@node Syntax of aggregate projects,package Builder in aggregate projects,Performance improvements in builder,Aggregate Projects +@anchor{gnat_ugn/gnat_project_manager id32}@anchor{18a}@anchor{gnat_ugn/gnat_project_manager syntax-of-aggregate-projects}@anchor{18b} +@subsection Syntax of aggregate projects -@smallexample @c ada -@b{with} Aux; -@b{procedure} Test @b{is} -@b{begin} - Aux.Used (10); -@b{end} Test; +An aggregate project follows the general syntax of project files. The +recommended extension is still @code{.gpr}. However, a special +@cite{aggregate} qualifier must be put before the keyword +@cite{project}. -@b{package} Aux @b{is} - Used_Data : Integer; - Unused_Data : Integer; +An aggregate project cannot @emph{with} any other project (standard or +aggregate), except an abstract project which can be used to share attribute +values. Also, aggregate projects cannot be extended or imported though a +@emph{with} clause by any other project. Building other aggregate projects from +an aggregate project is done through the Project_Files attribute (see below). - @b{procedure} Used (Data : Integer); - @b{procedure} Unused (Data : Integer); -@b{end} Aux; +An aggregate project does not have any source files directly (only +through other standard projects). Therefore a number of the standard +attributes and packages are forbidden in an aggregate project. Here is the +(non exhaustive) list: -@b{package} @b{body} Aux @b{is} - @b{procedure} Used (Data : Integer) @b{is} - @b{begin} - Used_Data := Data; - @b{end} Used; - @b{procedure} Unused (Data : Integer) @b{is} - @b{begin} - Unused_Data := Data; - @b{end} Unused; -@b{end} Aux; -@end smallexample +@itemize * -@noindent -@code{Unused} and @code{Unused_Data} are never referenced in this code -excerpt, and hence they may be safely removed from the final executable. +@item +Languages -@smallexample -$ gnatmake test +@item +Source_Files, Source_List_File and other attributes dealing with +list of sources. -$ nm test | grep used -020015f0 T aux__unused -02005d88 B aux__unused_data -020015cc T aux__used -02005d84 B aux__used_data +@item +Source_Dirs, Exec_Dir and Object_Dir -$ gnatmake test -cargs -fdata-sections -ffunction-sections \ - -largs -Wl,--gc-sections +@item +Library_Dir, Library_Name and other library-related attributes -$ nm test | grep used -02005350 T aux__used -0201ffe0 B aux__used_data -@end smallexample +@item +Main -@noindent -It can be observed that the procedure @code{Unused} and the object -@code{Unused_Data} are removed by the linker when using the -appropriate options. +@item +Roots -@c ******************************** -@node Renaming Files with gnatchop -@chapter Renaming Files with @code{gnatchop} -@findex gnatchop +@item +Externally_Built -@noindent -This chapter discusses how to handle files with multiple units by using -the @code{gnatchop} utility. This utility is also useful in renaming -files to meet the standard GNAT default file naming conventions. +@item +Inherit_Source_Path -@menu -* Handling Files with Multiple Units:: -* Operating gnatchop in Compilation Mode:: -* Command Line for gnatchop:: -* Switches for gnatchop:: -* Examples of gnatchop Usage:: -@end menu +@item +Excluded_Source_Dirs -@node Handling Files with Multiple Units -@section Handling Files with Multiple Units +@item +Locally_Removed_Files -@noindent -The basic compilation model of GNAT requires that a file submitted to the -compiler have only one unit and there be a strict correspondence -between the file name and the unit name. +@item +Excluded_Source_Files -The @code{gnatchop} utility allows both of these rules to be relaxed, -allowing GNAT to process files which contain multiple compilation units -and files with arbitrary file names. @code{gnatchop} -reads the specified file and generates one or more output files, -containing one unit per file. The unit and the file name correspond, -as required by GNAT. +@item +Excluded_Source_List_File -If you want to permanently restructure a set of ``foreign'' files so that -they match the GNAT rules, and do the remaining development using the -GNAT structure, you can simply use @command{gnatchop} once, generate the -new set of files and work with them from that point on. +@item +Interfaces +@end itemize -Alternatively, if you want to keep your files in the ``foreign'' format, -perhaps to maintain compatibility with some other Ada compilation -system, you can set up a procedure where you use @command{gnatchop} each -time you compile, regarding the source files that it writes as temporary -files that you throw away. +The only package that is authorized (albeit optional) is +Builder. Other packages (in particular Compiler, Binder and Linker) +are forbidden. -Note that if your file containing multiple units starts with a byte order -mark (BOM) specifying UTF-8 encoding, then the files generated by gnatchop -will each start with a copy of this BOM, meaning that they can be compiled -automatically in UTF-8 mode without needing to specify an explicit encoding. +The following three attributes can be used only in an aggregate project: -@node Operating gnatchop in Compilation Mode -@section Operating gnatchop in Compilation Mode +@geindex Project_Files (GNAT Project Manager) -@noindent -The basic function of @code{gnatchop} is to take a file with multiple units -and split it into separate files. The boundary between files is reasonably -clear, except for the issue of comments and pragmas. In default mode, the -rule is that any pragmas between units belong to the previous unit, except -that configuration pragmas always belong to the following unit. Any comments -belong to the following unit. These rules -almost always result in the right choice of -the split point without needing to mark it explicitly and most users will -find this default to be what they want. In this default mode it is incorrect to -submit a file containing only configuration pragmas, or one that ends in -configuration pragmas, to @code{gnatchop}. +@strong{Project_Files}: -However, using a special option to activate ``compilation mode'', -@code{gnatchop} -can perform another function, which is to provide exactly the semantics -required by the RM for handling of configuration pragmas in a compilation. -In the absence of configuration pragmas (at the main file level), this -option has no effect, but it causes such configuration pragmas to be handled -in a quite different manner. +@quotation -First, in compilation mode, if @code{gnatchop} is given a file that consists of -only configuration pragmas, then this file is appended to the -@file{gnat.adc} file in the current directory. This behavior provides -the required behavior described in the RM for the actions to be taken -on submitting such a file to the compiler, namely that these pragmas -should apply to all subsequent compilations in the same compilation -environment. Using GNAT, the current directory, possibly containing a -@file{gnat.adc} file is the representation -of a compilation environment. For more information on the -@file{gnat.adc} file, see @ref{Handling of Configuration Pragmas}. +This attribute is compulsory (or else we are not aggregating any project, +and thus not doing anything). It specifies a list of @code{.gpr} files +that are grouped in the aggregate. The list may be empty. The project +files can be either other aggregate projects, or standard projects. When +grouping standard projects, you can have both the root of a project tree +(and you do not need to specify all its imported projects), and any project +within the tree. + +Basically, the idea is to specify all those projects that have +main programs you want to build and link, or libraries you want to +build. You can even specify projects that do not use the Main +attribute nor the @cite{Library_*} attributes, and the result will be to +build all their source files (not just the ones needed by other +projects). + +The file can include paths (absolute or relative). Paths are relative to +the location of the aggregate project file itself (if you use a base name, +we expect to find the .gpr file in the same directory as the aggregate +project file). The environment variables @cite{ADA_PROJECT_PATH}, +@cite{GPR_PROJECT_PATH} and @cite{GPR_PROJECT_PATH_FILE} are not used to find +the project files. The extension @code{.gpr} is mandatory, since this attribute +contains file names, not project names. + +Paths can also include the @cite{"*"} and @cite{"**"} globbing patterns. The +latter indicates that any subdirectory (recursively) will be +searched for matching files. The latter (@cite{"**"}) can only occur at the +last position in the directory part (ie @cite{"a/**/*.gpr"} is supported, but +not @cite{"**/a/*.gpr"}). Starting the pattern with @cite{"**"} is equivalent +to starting with @cite{"./**"}. + +For now, the pattern @cite{"*"} is only allowed in the filename part, not +in the directory part. This is mostly for efficiency reasons to limit the +number of system calls that are needed. + +Here are a few valid examples: + +@example +for Project_Files use ("a.gpr", "subdir/b.gpr"); +-- two specific projects relative to the directory of agg.gpr + +for Project_Files use ("/.gpr"); +-- all projects recursively +@end example +@end quotation -Second, in compilation mode, if @code{gnatchop} -is given a file that starts with -configuration pragmas, and contains one or more units, then these -configuration pragmas are prepended to each of the chopped files. This -behavior provides the required behavior described in the RM for the -actions to be taken on compiling such a file, namely that the pragmas -apply to all units in the compilation, but not to subsequently compiled -units. +@geindex Project_Path (GNAT Project Manager) -Finally, if configuration pragmas appear between units, they are appended -to the previous unit. This results in the previous unit being illegal, -since the compiler does not accept configuration pragmas that follow -a unit. This provides the required RM behavior that forbids configuration -pragmas other than those preceding the first compilation unit of a -compilation. +@strong{Project_Path}: -For most purposes, @code{gnatchop} will be used in default mode. The -compilation mode described above is used only if you need exactly -accurate behavior with respect to compilations, and you have files -that contain multiple units and configuration pragmas. In this -circumstance the use of @code{gnatchop} with the compilation mode -switch provides the required behavior, and is for example the mode -in which GNAT processes the ACVC tests. +@quotation -@node Command Line for gnatchop -@section Command Line for @code{gnatchop} +This attribute can be used to specify a list of directories in +which to look for project files in @emph{with} declarations. -@noindent -The @code{gnatchop} command has the form: +When you specify a project in Project_Files (say @cite{x/y/a.gpr}), and +@cite{a.gpr} imports a project @cite{b.gpr}, only @cite{b.gpr} is searched in +the project path. @cite{a.gpr} must be exactly at +@cite{<dir of the aggregate>/x/y/a.gpr}. -@smallexample -@c $ gnatchop switches @var{file name} @r{[}@var{file name} @dots{}@r{]} -@c @ovar{directory} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatchop switches @var{file name} @r{[}@var{file name} @dots{}@r{]} - @r{[}@var{directory}@r{]} -@end smallexample +This attribute, however, does not affect the search for the aggregated +project files specified with @cite{Project_Files}. -@noindent -The only required argument is the file name of the file to be chopped. -There are no restrictions on the form of this file name. The file itself -contains one or more Ada units, in normal GNAT format, concatenated -together. As shown, more than one file may be presented to be chopped. +Each aggregate project has its own @cite{Project_Path} (that is if +@cite{agg1.gpr} includes @cite{agg2.gpr}, they can potentially both have a +different @cite{Project_Path}). -When run in default mode, @code{gnatchop} generates one output file in -the current directory for each unit in each of the files. +This project path is defined as the concatenation, in that order, of: -@var{directory}, if specified, gives the name of the directory to which -the output files will be written. If it is not specified, all files are -written to the current directory. -For example, given a -file called @file{hellofiles} containing +@itemize * -@smallexample @c ada -@group -@cartouche -@b{procedure} hello; +@item +the current directory; -@b{with} Text_IO; @b{use} Text_IO; -@b{procedure} hello @b{is} -@b{begin} - Put_Line ("Hello"); -@b{end} hello; -@end cartouche -@end group -@end smallexample +@item +followed by the command line -aP switches; -@noindent -the command +@item +then the directories from the GPR_PROJECT_PATH and ADA_PROJECT_PATH environment +variables; -@smallexample -$ gnatchop hellofiles -@end smallexample +@item +then the directories from the Project_Path attribute; -@noindent -generates two files in the current directory, one called -@file{hello.ads} containing the single line that is the procedure spec, -and the other called @file{hello.adb} containing the remaining text. The -original file is not affected. The generated files can be compiled in -the normal manner. +@item +and finally the predefined directories. +@end itemize -@noindent -When gnatchop is invoked on a file that is empty or that contains only empty -lines and/or comments, gnatchop will not fail, but will not produce any -new sources. +In the example above, agg2.gpr's project path is not influenced by +the attribute agg1'Project_Path, nor is agg1 influenced by +agg2'Project_Path. + +This can potentially lead to errors. Consider the following example: + +@c -- +@c -- +---------------+ +----------------+ +@c -- | Agg1.gpr |-=--includes--=-->| Agg2.gpr | +@c -- | 'project_path| | 'project_path | +@c -- | | | | +@c -- +---------------+ +----------------+ +@c -- : : +@c -- includes includes +@c -- : : +@c -- v v +@c -- +-------+ +---------+ +@c -- | P.gpr |<---------- withs --------| Q.gpr | +@c -- +-------+---------\ +---------+ +@c -- | | +@c -- withs | +@c -- | | +@c -- v v +@c -- +-------+ +---------+ +@c -- | R.gpr | | R'.gpr | +@c -- +-------+ +---------+ + +@image{project-manager-figure,,,,png} + +When looking for p.gpr, both aggregates find the same physical file on +the disk. However, it might happen that with their different project +paths, both aggregate projects would in fact find a different r.gpr. +Since we have a common project (p.gpr) "with"ing two different r.gpr, +this will be reported as an error by the builder. + +Directories are relative to the location of the aggregate project file. -For example, given a -file called @file{toto.txt} containing +Example: -@smallexample @c ada -@group -@cartouche ---@i{ Just a comment} -@end cartouche -@end group -@end smallexample +@example +for Project_Path use ("/usr/local/gpr", "gpr/"); +@end example +@end quotation -@noindent -the command +@geindex External (GNAT Project Manager) -@smallexample -$ gnatchop toto.txt -@end smallexample +@strong{External}: -@noindent -will not produce any new file and will result in the following warnings: +@quotation -@smallexample -toto.txt:1:01: warning: empty file, contains no compilation units -no compilation units found -no source files written -@end smallexample +This attribute can be used to set the value of environment +variables as retrieved through the @cite{external} function +in projects. It does not affect the environment variables +themselves (so for instance you cannot use it to change the value +of your PATH as seen from the spawned compiler). -@node Switches for gnatchop -@section Switches for @code{gnatchop} +This attribute affects the external values as seen in the rest of +the aggregate project, and in the aggregated projects. -@noindent -@command{gnatchop} recognizes the following switches: +The exact value of external a variable comes from one of three +sources (each level overrides the previous levels): -@table @option -@c !sort! -@item --version -@cindex @option{--version} @command{gnatchop} -Display Copyright and version, then exit disregarding all other options. +@itemize * -@item --help -@cindex @option{--help} @command{gnatchop} -If @option{--version} was not used, display usage, then exit disregarding -all other options. +@item +An External attribute in aggregate project, for instance +@cite{for External ("BUILD_MODE") use "DEBUG"}; -@item -c -@cindex @option{-c} (@code{gnatchop}) -Causes @code{gnatchop} to operate in compilation mode, in which -configuration pragmas are handled according to strict RM rules. See -previous section for a full description of this mode. +@item +Environment variables. +These override the value given by the attribute, so that +users can override the value set in the (presumably shared +with others team members) aggregate project. -@item -gnat@var{xxx} -This passes the given @option{-gnat@var{xxx}} switch to @code{gnat} which is -used to parse the given file. Not all @var{xxx} options make sense, -but for example, the use of @option{-gnati2} allows @code{gnatchop} to -process a source file that uses Latin-2 coding for identifiers. +@item +The -X command line switch to @emph{gprbuild}. +This always takes precedence. +@end itemize -@item -h -Causes @code{gnatchop} to generate a brief help summary to the standard -output file showing usage information. +This attribute is only taken into account in the main aggregate +project (i.e. the one specified on the command line to @emph{gprbuild}), +and ignored in other aggregate projects. It is invalid +in standard projects. +The goal is to have a consistent value in all +projects that are built through the aggregate, which would not +be the case in the diamond case: A groups the aggregate +projects B and C, which both (either directly or indirectly) +build the project P. If B and C could set different values for +the environment variables, we would have two different views of +P, which in particular might impact the list of source files in P. +@end quotation -@item -k@var{mm} -@cindex @option{-k} (@code{gnatchop}) -Limit generated file names to the specified number @code{mm} -of characters. -This is useful if the -resulting set of files is required to be interoperable with systems -which limit the length of file names. -No space is allowed between the @option{-k} and the numeric value. The numeric -value may be omitted in which case a default of @option{-k8}, -suitable for use -with DOS-like file systems, is used. If no @option{-k} switch -is present then -there is no limit on the length of file names. +@node package Builder in aggregate projects,,Syntax of aggregate projects,Aggregate Projects +@anchor{gnat_ugn/gnat_project_manager package-builder-in-aggregate-projects}@anchor{18c}@anchor{gnat_ugn/gnat_project_manager id33}@anchor{18d} +@subsection package Builder in aggregate projects -@item -p -@cindex @option{-p} (@code{gnatchop}) -Causes the file modification time stamp of the input file to be -preserved and used for the time stamp of the output file(s). This may be -useful for preserving coherency of time stamps in an environment where -@code{gnatchop} is used as part of a standard build process. -@item -q -@cindex @option{-q} (@code{gnatchop}) -Causes output of informational messages indicating the set of generated -files to be suppressed. Warnings and error messages are unaffected. +As mentioned above, only the package Builder can be specified in +an aggregate project. In this package, only the following attributes +are valid: -@item -r -@cindex @option{-r} (@code{gnatchop}) -@findex Source_Reference -Generate @code{Source_Reference} pragmas. Use this switch if the output -files are regarded as temporary and development is to be done in terms -of the original unchopped file. This switch causes -@code{Source_Reference} pragmas to be inserted into each of the -generated files to refers back to the original file name and line number. -The result is that all error messages refer back to the original -unchopped file. -In addition, the debugging information placed into the object file (when -the @option{-g} switch of @command{gcc} or @command{gnatmake} is -specified) -also refers back to this original file so that tools like profilers and -debuggers will give information in terms of the original unchopped file. +@geindex Switches (GNAT Project Manager) -If the original file to be chopped itself contains -a @code{Source_Reference} -pragma referencing a third file, then gnatchop respects -this pragma, and the generated @code{Source_Reference} pragmas -in the chopped file refer to the original file, with appropriate -line numbers. This is particularly useful when @code{gnatchop} -is used in conjunction with @code{gnatprep} to compile files that -contain preprocessing statements and multiple units. +@strong{Switches}: -@item -v -@cindex @option{-v} (@code{gnatchop}) -Causes @code{gnatchop} to operate in verbose mode. The version -number and copyright notice are output, as well as exact copies of -the gnat1 commands spawned to obtain the chop control information. +@quotation -@item -w -@cindex @option{-w} (@code{gnatchop}) -Overwrite existing file names. Normally @code{gnatchop} regards it as a -fatal error if there is already a file with the same name as a -file it would otherwise output, in other words if the files to be -chopped contain duplicated units. This switch bypasses this -check, and causes all but the last instance of such duplicated -units to be skipped. +This attribute gives the list of switches to use for @emph{gprbuild}. +Because no mains can be specified for aggregate projects, the only possible +index for attribute @cite{Switches} is @cite{others}. All other indexes will +be ignored. -@item --GCC=@var{xxxx} -@cindex @option{--GCC=} (@code{gnatchop}) -Specify the path of the GNAT parser to be used. When this switch is used, -no attempt is made to add the prefix to the GNAT parser executable. -@end table +Example: -@node Examples of gnatchop Usage -@section Examples of @code{gnatchop} Usage +@example +for Switches (others) use ("-v", "-k", "-j8"); +@end example -@table @code -@item gnatchop -w hello_s.ada prerelease/files +These switches are only read from the main aggregate project (the +one passed on the command line), and ignored in all other aggregate +projects or projects. -Chops the source file @file{hello_s.ada}. The output files will be -placed in the directory @file{prerelease/files}, -overwriting any -files with matching names in that directory (no files in the current -directory are modified). +It can only contain builder switches, not compiler switches. +@end quotation -@item gnatchop archive -Chops the source file @file{archive} -into the current directory. One -useful application of @code{gnatchop} is in sending sets of sources -around, for example in email messages. The required sources are simply -concatenated (for example, using a Unix @code{cat} -command), and then -@command{gnatchop} is used at the other end to reconstitute the original -file names. +@geindex Global_Compilation_Switches (GNAT Project Manager) -@item gnatchop file1 file2 file3 direc -Chops all units in files @file{file1}, @file{file2}, @file{file3}, placing -the resulting files in the directory @file{direc}. Note that if any units -occur more than once anywhere within this set of files, an error message -is generated, and no files are written. To override this check, use the -@option{-w} switch, -in which case the last occurrence in the last file will -be the one that is output, and earlier duplicate occurrences for a given -unit will be skipped. -@end table +@strong{Global_Compilation_Switches} + +@quotation + +This attribute gives the list of compiler switches for the various +languages. For instance, + +@example +for Global_Compilation_Switches ("Ada") use ("O1", "-g"); +for Global_Compilation_Switches ("C") use ("-O2"); +@end example + +This attribute is only taken into account in the aggregate project +specified on the command line, not in other aggregate projects. + +In the projects grouped by that aggregate, the attribute +Builder.Global_Compilation_Switches is also ignored. However, the +attribute Compiler.Default_Switches will be taken into account (but +that of the aggregate have higher priority). The attribute +Compiler.Switches is also taken into account and can be used to +override the switches for a specific file. As a result, it always +has priority. + +The rules are meant to avoid ambiguities when compiling. For +instance, aggregate project Agg groups the projects A and B, that +both depend on C. Here is an extra for all of these projects: + +@example +aggregate project Agg is + for Project_Files use ("a.gpr", "b.gpr"); + package Builder is + for Global_Compilation_Switches ("Ada") use ("-O2"); + end Builder; +end Agg; + +with "c.gpr"; +project A is + package Builder is + for Global_Compilation_Switches ("Ada") use ("-O1"); + -- ignored + end Builder; + + package Compiler is + for Default_Switches ("Ada") + use ("-O1", "-g"); + for Switches ("a_file1.adb") + use ("-O0"); + end Compiler; +end A; + +with "c.gpr"; +project B is + package Compiler is + for Default_Switches ("Ada") use ("-O0"); + end Compiler; +end B; + +project C is + package Compiler is + for Default_Switches ("Ada") + use ("-O3", + "-gnatn"); + for Switches ("c_file1.adb") + use ("-O0", "-g"); + end Compiler; +end C; +@end example + +then the following switches are used: + + +@itemize * + +@item +all files from project A except a_file1.adb are compiled +with "-O2 -g", since the aggregate project has priority. + +@item +the file a_file1.adb is compiled with +"-O0", since the Compiler.Switches has priority + +@item +all files from project B are compiled with +"-O2", since the aggregate project has priority + +@item +all files from C are compiled with "-O2 -gnatn", except for +c_file1.adb which is compiled with "-O0 -g" +@end itemize + +Even though C is seen through two paths (through A and through +B), the switches used by the compiler are unambiguous. +@end quotation + +@geindex Global_Configuration_Pragmas (GNAT Project Manager) + +@strong{Global_Configuration_Pragmas} + +@quotation + +This attribute can be used to specify a file containing +configuration pragmas, to be passed to the Ada compiler. Since we +ignore the package Builder in other aggregate projects and projects, +only those pragmas defined in the main aggregate project will be +taken into account. + +Projects can locally add to those by using the +@cite{Compiler.Local_Configuration_Pragmas} attribute if they need. +@end quotation + +@geindex Global_Config_File (GNAT Project Manager) + +@strong{Global_Config_File} + +@quotation + +This attribute, indexed with a language name, can be used to specify a config +when compiling sources of the language. For Ada, these files are configuration +pragmas files. +@end quotation -@node Configuration Pragmas -@chapter Configuration Pragmas -@cindex Configuration pragmas -@cindex Pragmas, configuration +For projects that are built through the aggregate, the package Builder +is ignored, except for the Executable attribute which specifies the +name of the executables resulting from the link of the main programs, and +for the Executable_Suffix. + +@node Aggregate Library Projects,Project File Reference,Aggregate Projects,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager id34}@anchor{18e}@anchor{gnat_ugn/gnat_project_manager aggregate-library-projects}@anchor{18f} +@section Aggregate Library Projects + + +Aggregate library projects make it possible to build a single library +using object files built using other standard or library +projects. This gives the flexibility to describe an application as +having multiple modules (a GUI, database access, ...) using different +project files (so possibly built with different compiler options) and +yet create a single library (static or relocatable) out of the +corresponding object files. @menu -* Handling of Configuration Pragmas:: -* The Configuration Pragmas Files:: +* Building aggregate library projects:: +* Syntax of aggregate library projects:: + @end menu -@noindent -Configuration pragmas include those pragmas described as -such in the Ada Reference Manual, as well as -implementation-dependent pragmas that are configuration pragmas. -@xref{Implementation Defined Pragmas,,, gnat_rm, GNAT Reference Manual}, -for details on these additional GNAT-specific configuration pragmas. -Most notably, the pragma @code{Source_File_Name}, which allows -specifying non-default names for source files, is a configuration -pragma. The following is a complete list of configuration pragmas -recognized by GNAT: +@node Building aggregate library projects,Syntax of aggregate library projects,,Aggregate Library Projects +@anchor{gnat_ugn/gnat_project_manager building-aggregate-library-projects}@anchor{190}@anchor{gnat_ugn/gnat_project_manager id35}@anchor{191} +@subsection Building aggregate library projects -@smallexample - Ada_83 - Ada_95 - Ada_05 - Ada_2005 - Ada_12 - Ada_2012 - Allow_Integer_Address - Annotate - Assertion_Policy - Assume_No_Invalid_Values - C_Pass_By_Copy - Check_Name - Check_Policy - Compile_Time_Error - Compile_Time_Warning - Compiler_Unit - Component_Alignment - Convention_Identifier - Debug_Policy - Detect_Blocking - Default_Storage_Pool - Discard_Names - Elaboration_Checks - Eliminate - Extend_System - Extensions_Allowed - External_Name_Casing - Fast_Math - Favor_Top_Level - Float_Representation - Implicit_Packing - Initialize_Scalars - Interrupt_State - License - Locking_Policy - Long_Float - No_Run_Time - No_Strict_Aliasing - Normalize_Scalars - Optimize_Alignment - Persistent_BSS - Polling - Priority_Specific_Dispatching - Profile - Profile_Warnings - Propagate_Exceptions - Queuing_Policy - Ravenscar - Restricted_Run_Time - Restrictions - Restrictions_Warnings - Reviewable - Short_Circuit_And_Or - Source_File_Name - Source_File_Name_Project - SPARK_Mode - Style_Checks - Suppress - Suppress_Exception_Locations - Task_Dispatching_Policy - Universal_Data - Unsuppress - Use_VADS_Size - Validity_Checks - Warnings - Wide_Character_Encoding -@end smallexample - -@node Handling of Configuration Pragmas -@section Handling of Configuration Pragmas -Configuration pragmas may either appear at the start of a compilation -unit, or they can appear in a configuration pragma file to apply to -all compilations performed in a given compilation environment. +For example, we can define an aggregate project Agg that groups A, B +and C: -GNAT also provides the @code{gnatchop} utility to provide an automatic -way to handle configuration pragmas following the semantics for -compilations (that is, files with multiple units), described in the RM. -See @ref{Operating gnatchop in Compilation Mode} for details. -However, for most purposes, it will be more convenient to edit the -@file{gnat.adc} file that contains configuration pragmas directly, -as described in the following section. +@example +aggregate library project Agg is + for Project_Files use ("a.gpr", "b.gpr", "c.gpr"); + for Library_Name use ("agg"); + for Library_Dir use ("lagg"); +end Agg; +@end example -In the case of @code{Restrictions} pragmas appearing as configuration -pragmas in individual compilation units, the exact handling depends on -the type of restriction. +Then, when you build with: -Restrictions that require partition-wide consistency (like -@code{No_Tasking}) are -recognized wherever they appear -and can be freely inherited, e.g. from a with'ed unit to the with'ing -unit. This makes sense since the binder will in any case insist on seeing -consistent use, so any unit not conforming to any restrictions that are -anywhere in the partition will be rejected, and you might as well find -that out at compile time rather than at bind time. +@example +gprbuild agg.gpr +@end example -For restrictions that do not require partition-wide consistency, e.g. -SPARK or No_Implementation_Attributes, in general the restriction applies -only to the unit in which the pragma appears, and not to any other units. +This will build all units from projects A, B and C and will create a +static library named @code{libagg.a} in the @code{lagg} +directory. An aggregate library project has the same set of +restriction as a standard library project. -The exception is No_Elaboration_Code which always applies to the entire -object file from a compilation, i.e. to the body, spec, and all subunits. -This restriction can be specified in a configuration pragma file, or it -can be on the body and/or the spec (in eithe case it applies to all the -relevant units). It can appear on a subunit only if it has previously -appeared in the body of spec. +Note that a shared aggregate library project cannot aggregate a +static library project. In platforms where a compiler option is +required to create relocatable object files, a Builder package in the +aggregate library project may be used: -@node The Configuration Pragmas Files -@section The Configuration Pragmas Files -@cindex @file{gnat.adc} +@example +aggregate library project Agg is + for Project_Files use ("a.gpr", "b.gpr", "c.gpr"); + for Library_Name use ("agg"); + for Library_Dir use ("lagg"); + for Library_Kind use "relocatable"; -@noindent -In GNAT a compilation environment is defined by the current -directory at the time that a compile command is given. This current -directory is searched for a file whose name is @file{gnat.adc}. If -this file is present, it is expected to contain one or more -configuration pragmas that will be applied to the current compilation. -However, if the switch @option{-gnatA} is used, @file{gnat.adc} is not -considered. When taken into account, @file{gnat.adc} is added to the -dependencies, so that if @file{gnat.adc} is modified later, an invocation of -@command{gnatmake} will recompile the source. + package Builder is + for Global_Compilation_Switches ("Ada") use ("-fPIC"); + end Builder; +end Agg; +@end example -Configuration pragmas may be entered into the @file{gnat.adc} file -either by running @code{gnatchop} on a source file that consists only of -configuration pragmas, or more conveniently by direct editing of the -@file{gnat.adc} file, which is a standard format source file. +With the above aggregate library Builder package, the @cite{-fPIC} +option will be passed to the compiler when building any source code +from projects @code{a.gpr}, @code{b.gpr} and @code{c.gpr}. -In addition to @file{gnat.adc}, additional files containing configuration -pragmas may be applied to the current compilation using the switch -@option{-gnatec=}@var{path}. @var{path} must designate an existing file that -contains only configuration pragmas. These configuration pragmas are -in addition to those found in @file{gnat.adc} (provided @file{gnat.adc} -is present and switch @option{-gnatA} is not used). +@node Syntax of aggregate library projects,,Building aggregate library projects,Aggregate Library Projects +@anchor{gnat_ugn/gnat_project_manager syntax-of-aggregate-library-projects}@anchor{192}@anchor{gnat_ugn/gnat_project_manager id36}@anchor{193} +@subsection Syntax of aggregate library projects -It is allowable to specify several switches @option{-gnatec=}, all of which -will be taken into account. -Files containing configuration pragmas specified with switches -@option{-gnatec=} are added to the dependencies, unless they are -temporary files. A file is considered temporary if its name ends in -@file{.tmp} or @file{.TMP}. Certain tools follow this naming -convention because they pass information to @command{gcc} via -temporary files that are immediately deleted; it doesn't make sense to -depend on a file that no longer exists. Such tools include -@command{gprbuild}, @command{gnatmake}, and @command{gnatcheck}. +An aggregate library project follows the general syntax of project +files. The recommended extension is still @code{.gpr}. However, a special +@cite{aggregate library} qualifier must be put before the keyword +@cite{project}. -If you are using project file, a separate mechanism is provided using -project attributes, see @ref{Specifying Configuration Pragmas} for more -details. +An aggregate library project cannot @emph{with} any other project +(standard or aggregate), except an abstract project which can be used +to share attribute values. + +An aggregate library project does not have any source files directly (only +through other standard projects). Therefore a number of the standard +attributes and packages are forbidden in an aggregate library +project. Here is the (non exhaustive) list: -@node Handling Arbitrary File Naming Conventions with gnatname -@chapter Handling Arbitrary File Naming Conventions with @code{gnatname} -@cindex Arbitrary File Naming Conventions +@itemize * + +@item +Languages + +@item +Source_Files, Source_List_File and other attributes dealing with +list of sources. + +@item +Source_Dirs, Exec_Dir and Object_Dir + +@item +Main + +@item +Roots + +@item +Externally_Built + +@item +Inherit_Source_Path + +@item +Excluded_Source_Dirs + +@item +Locally_Removed_Files + +@item +Excluded_Source_Files + +@item +Excluded_Source_List_File + +@item +Interfaces +@end itemize + +The only package that is authorized (albeit optional) is Builder. + +The Project_Files attribute (See @ref{16e,,Aggregate Projects}) is used to +described the aggregated projects whose object files have to be +included into the aggregate library. The environment variables +@cite{ADA_PROJECT_PATH}, @cite{GPR_PROJECT_PATH} and +@cite{GPR_PROJECT_PATH_FILE} are not used to find the project files. + +@node Project File Reference,,Aggregate Library Projects,GNAT Project Manager +@anchor{gnat_ugn/gnat_project_manager id37}@anchor{194}@anchor{gnat_ugn/gnat_project_manager project-file-reference}@anchor{14d} +@section Project File Reference + + +This section describes the syntactic structure of project files, the various +constructs that can be used. Finally, it ends with a summary of all available +attributes. @menu -* Arbitrary File Naming Conventions:: -* Running gnatname:: -* Switches for gnatname:: -* Examples of gnatname Usage:: +* Project Declaration:: +* Qualified Projects:: +* Declarations:: +* Packages:: +* Expressions:: +* External Values:: +* Typed String Declaration:: +* Variables:: +* Case Constructions:: +* Attributes:: + @end menu -@node Arbitrary File Naming Conventions -@section Arbitrary File Naming Conventions +@node Project Declaration,Qualified Projects,,Project File Reference +@anchor{gnat_ugn/gnat_project_manager id38}@anchor{195}@anchor{gnat_ugn/gnat_project_manager project-declaration}@anchor{196} +@subsection Project Declaration + + +Project files have an Ada-like syntax. The minimal project file is: + +@example +project Empty is +end Empty; +@end example + +The identifier @cite{Empty} is the name of the project. +This project name must be present after the reserved +word @cite{end} at the end of the project file, followed by a semi-colon. + +@strong{Identifiers} (i.e., the user-defined names such as project or variable names) +have the same syntax as Ada identifiers: they must start with a letter, +and be followed by zero or more letters, digits or underscore characters; +it is also illegal to have two underscores next to each other. Identifiers +are always case-insensitive ("Name" is the same as "name"). + +@example +simple_name ::= identifier +name ::= simple_name @{ . simple_name @} +@end example + +@strong{Strings} are used for values of attributes or as indexes for these +attributes. They are in general case sensitive, except when noted +otherwise (in particular, strings representing file names will be case +insensitive on some systems, so that "file.adb" and "File.adb" both +represent the same file). + +@strong{Reserved words} are the same as for standard Ada 95, and cannot +be used for identifiers. In particular, the following words are currently +used in project files, but others could be added later on. In bold are the +extra reserved words in project files: +@code{all}, @code{at}, @code{case}, @code{end}, @code{for}, @code{is}, @code{limited}, +@code{null}, @code{others}, @code{package}, @code{renames}, @code{type}, @code{use}, @code{when}, +@code{with}, @strong{extends}, @strong{external}, @strong{project}. + +@strong{Comments} in project files have the same syntax as in Ada, two consecutive +hyphens through the end of the line. + +A project may be an @strong{independent project}, entirely defined by a single +project file. Any source file in an independent project depends only +on the predefined library and other source files in the same project. +But a project may also depend on other projects, either by importing them +through @strong{with clauses}, or by @strong{extending} at most one other project. Both +types of dependency can be used in the same project. + +A path name denotes a project file. It can be absolute or relative. +An absolute path name includes a sequence of directories, in the syntax of +the host operating system, that identifies uniquely the project file in the +file system. A relative path name identifies the project file, relative +to the directory that contains the current project, or relative to a +directory listed in the environment variables ADA_PROJECT_PATH and +GPR_PROJECT_PATH. Path names are case sensitive if file names in the host +operating system are case sensitive. As a special case, the directory +separator can always be "/" even on Windows systems, so that project files +can be made portable across architectures. +The syntax of the environment variables ADA_PROJECT_PATH and +GPR_PROJECT_PATH is a list of directory names separated by colons on UNIX and +semicolons on Windows. + +A given project name can appear only once in a context clause. + +It is illegal for a project imported by a context clause to refer, directly +or indirectly, to the project in which this context clause appears (the +dependency graph cannot contain cycles), except when one of the with clauses +in the cycle is a @strong{limited with}. + +@example +with "other_project.gpr"; +project My_Project extends "extended.gpr" is +end My_Project; +@end example + +These dependencies form a @strong{directed graph}, potentially cyclic when using +@strong{limited with}. The subgraph reflecting the @strong{extends} relations is a tree. + +A project's @strong{immediate sources} are the source files directly defined by +that project, either implicitly by residing in the project source directories, +or explicitly through any of the source-related attributes. +More generally, a project's @strong{sources} are the immediate sources of the +project together with the immediate sources (unless overridden) of any project +on which it depends directly or indirectly. + +A @strong{project hierarchy} can be created, where projects are children of +other projects. The name of such a child project must be @cite{Parent.Child}, +where @cite{Parent} is the name of the parent project. In particular, this +makes all @emph{with} clauses of the parent project automatically visible +in the child project. + +@example +project ::= context_clause project_declaration + +context_clause ::= @{with_clause@} +with_clause ::= *with* path_name @{ , path_name @} ; +path_name ::= string_literal + +project_declaration ::= simple_project_declaration | project_extension +simple_project_declaration ::= + project <project_>name is + @{declarative_item@} + end <project_>simple_name; +@end example + +@node Qualified Projects,Declarations,Project Declaration,Project File Reference +@anchor{gnat_ugn/gnat_project_manager qualified-projects}@anchor{173}@anchor{gnat_ugn/gnat_project_manager id39}@anchor{197} +@subsection Qualified Projects + + +Before the reserved @cite{project}, there may be one or two @strong{qualifiers}, that +is identifiers or reserved words, to qualify the project. +The current list of qualifiers is: -@noindent -The GNAT compiler must be able to know the source file name of a compilation -unit. When using the standard GNAT default file naming conventions -(@code{.ads} for specs, @code{.adb} for bodies), the GNAT compiler -does not need additional information. -@noindent -When the source file names do not follow the standard GNAT default file naming -conventions, the GNAT compiler must be given additional information through -a configuration pragmas file (@pxref{Configuration Pragmas}) -or a project file. -When the non-standard file naming conventions are well-defined, -a small number of pragmas @code{Source_File_Name} specifying a naming pattern -(@pxref{Alternative File Naming Schemes}) may be sufficient. However, -if the file naming conventions are irregular or arbitrary, a number -of pragma @code{Source_File_Name} for individual compilation units -must be defined. -To help maintain the correspondence between compilation unit names and -source file names within the compiler, -GNAT provides a tool @code{gnatname} to generate the required pragmas for a -set of files. +@table @asis -@node Running gnatname -@section Running @code{gnatname} +@item @strong{abstract}: -@noindent -The usual form of the @code{gnatname} command is +Qualifies a project with no sources. +Such a project must either have no declaration of attributes @cite{Source_Dirs}, +@cite{Source_Files}, @cite{Languages} or @cite{Source_List_File}, or one of +@cite{Source_Dirs}, @cite{Source_Files}, or @cite{Languages} must be declared +as empty. If it extends another project, the project it extends must also be a +qualified abstract project. -@smallexample -@c $ gnatname @ovar{switches} @var{naming_pattern} @ovar{naming_patterns} -@c @r{[}--and @ovar{switches} @var{naming_pattern} @ovar{naming_patterns}@r{]} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatname @r{[}@var{switches}@r{]} @var{naming_pattern} @r{[}@var{naming_patterns}@r{]} - @r{[}--and @r{[}@var{switches}@r{]} @var{naming_pattern} @r{[}@var{naming_patterns}@r{]}@r{]} -@end smallexample +@item @strong{standard}: -@noindent -All of the arguments are optional. If invoked without any argument, -@code{gnatname} will display its usage. +A standard project is a non library project with sources. +This is the default (implicit) qualifier. -@noindent -When used with at least one naming pattern, @code{gnatname} will attempt to -find all the compilation units in files that follow at least one of the -naming patterns. To find these compilation units, -@code{gnatname} will use the GNAT compiler in syntax-check-only mode on all -regular files. +@item @strong{aggregate}: -@noindent -One or several Naming Patterns may be given as arguments to @code{gnatname}. -Each Naming Pattern is enclosed between double quotes (or single -quotes on Windows). -A Naming Pattern is a regular expression similar to the wildcard patterns -used in file names by the Unix shells or the DOS prompt. +A project whose sources are aggregated from other project files. -@noindent -@code{gnatname} may be called with several sections of directories/patterns. -Sections are separated by switch @code{--and}. In each section, there must be -at least one pattern. If no directory is specified in a section, the current -directory (or the project directory is @code{-P} is used) is implied. -The options other that the directory switches and the patterns apply globally -even if they are in different sections. +@item @strong{aggregate library}: -@noindent -Examples of Naming Patterns are +A library whose sources are aggregated from other project +or library project files. -@smallexample - "*.[12].ada" - "*.ad[sb]*" - "body_*" "spec_*" -@end smallexample +@item @strong{library}: -@noindent -For a more complete description of the syntax of Naming Patterns, -see the second kind of regular expressions described in @file{g-regexp.ads} -(the ``Glob'' regular expressions). +A library project must declare both attributes +Library_Name` and @cite{Library_Dir}. -@noindent -When invoked with no switch @code{-P}, @code{gnatname} will create a -configuration pragmas file @file{gnat.adc} in the current working directory, -with pragmas @code{Source_File_Name} for each file that contains a valid Ada -unit. +@item @strong{configuration}: -@node Switches for gnatname -@section Switches for @code{gnatname} +A configuration project cannot be in a project tree. +It describes compilers and other tools to @emph{gprbuild}. +@end table -@noindent -Switches for @code{gnatname} must precede any specified Naming Pattern. +@node Declarations,Packages,Qualified Projects,Project File Reference +@anchor{gnat_ugn/gnat_project_manager declarations}@anchor{198}@anchor{gnat_ugn/gnat_project_manager id40}@anchor{199} +@subsection Declarations -@noindent -You may specify any of the following switches to @code{gnatname}: -@table @option -@c !sort! +Declarations introduce new entities that denote types, variables, attributes, +and packages. Some declarations can only appear immediately within a project +declaration. Others can appear within a project or within a package. -@item --version -@cindex @option{--version} @command{gnatname} -Display Copyright and version, then exit disregarding all other options. +@example +declarative_item ::= simple_declarative_item + | typed_string_declaration + | package_declaration -@item --help -@cindex @option{--help} @command{gnatname} -If @option{--version} was not used, display usage, then exit disregarding -all other options. +simple_declarative_item ::= variable_declaration + | typed_variable_declaration + | attribute_declaration + | case_construction + | empty_declaration -@item --subdirs=<dir> -Real object, library or exec directories are subdirectories <dir> of the -specified ones. +empty_declaration ::= *null* ; +@end example -@item --no-backup -Do not create a backup copy of an existing project file. +An empty declaration is allowed anywhere a declaration is allowed. It has +no effect. -@item --and -Start another section of directories/patterns. +@node Packages,Expressions,Declarations,Project File Reference +@anchor{gnat_ugn/gnat_project_manager packages}@anchor{153}@anchor{gnat_ugn/gnat_project_manager id41}@anchor{19a} +@subsection Packages -@item -c@file{file} -@cindex @option{-c} (@code{gnatname}) -Create a configuration pragmas file @file{file} (instead of the default -@file{gnat.adc}). -There may be zero, one or more space between @option{-c} and -@file{file}. -@file{file} may include directory information. @file{file} must be -writable. There may be only one switch @option{-c}. -When a switch @option{-c} is -specified, no switch @option{-P} may be specified (see below). - -@item -d@file{dir} -@cindex @option{-d} (@code{gnatname}) -Look for source files in directory @file{dir}. There may be zero, one or more -spaces between @option{-d} and @file{dir}. -@file{dir} may end with @code{/**}, that is it may be of the form -@code{root_dir/**}. In this case, the directory @code{root_dir} and all of its -subdirectories, recursively, have to be searched for sources. -When a switch @option{-d} -is specified, the current working directory will not be searched for source -files, unless it is explicitly specified with a @option{-d} -or @option{-D} switch. -Several switches @option{-d} may be specified. -If @file{dir} is a relative path, it is relative to the directory of -the configuration pragmas file specified with switch -@option{-c}, -or to the directory of the project file specified with switch -@option{-P} or, -if neither switch @option{-c} -nor switch @option{-P} are specified, it is relative to the -current working directory. The directory -specified with switch @option{-d} must exist and be readable. - -@item -D@file{file} -@cindex @option{-D} (@code{gnatname}) -Look for source files in all directories listed in text file @file{file}. -There may be zero, one or more spaces between @option{-D} -and @file{file}. -@file{file} must be an existing, readable text file. -Each nonempty line in @file{file} must be a directory. -Specifying switch @option{-D} is equivalent to specifying as many -switches @option{-d} as there are nonempty lines in -@file{file}. - -@item -eL -Follow symbolic links when processing project files. -@item -f@file{pattern} -@cindex @option{-f} (@code{gnatname}) -Foreign patterns. Using this switch, it is possible to add sources of languages -other than Ada to the list of sources of a project file. -It is only useful if a -P switch is used. -For example, -@smallexample -gnatname -Pprj -f"*.c" "*.ada" -@end smallexample -@noindent -will look for Ada units in all files with the @file{.ada} extension, -and will add to the list of file for project @file{prj.gpr} the C files -with extension @file{.c}. - -@item -h -@cindex @option{-h} (@code{gnatname}) -Output usage (help) information. The output is written to @file{stdout}. - -@item -P@file{proj} -@cindex @option{-P} (@code{gnatname}) -Create or update project file @file{proj}. There may be zero, one or more space -between @option{-P} and @file{proj}. @file{proj} may include directory -information. @file{proj} must be writable. -There may be only one switch @option{-P}. -When a switch @option{-P} is specified, -no switch @option{-c} may be specified. -On all platforms, except on VMS, when @code{gnatname} is invoked for an -existing project file <proj>.gpr, a backup copy of the project file is created -in the project directory with file name <proj>.gpr.saved_x. 'x' is the first -non negative number that makes this backup copy a new file. +A project file may contain @strong{packages}, that group attributes (typically +all the attributes that are used by one of the GNAT tools). -@item -v -@cindex @option{-v} (@code{gnatname}) -Verbose mode. Output detailed explanation of behavior to @file{stdout}. -This includes name of the file written, the name of the directories to search -and, for each file in those directories whose name matches at least one of -the Naming Patterns, an indication of whether the file contains a unit, -and if so the name of the unit. +A package with a given name may only appear once in a project file. +The following packages are currently supported in project files +(See @ref{152,,Attributes} for the list of attributes that each can contain). -@item -v -v -@cindex @option{-v -v} (@code{gnatname}) -Very Verbose mode. In addition to the output produced in verbose mode, -for each file in the searched directories whose name matches none of -the Naming Patterns, an indication is given that there is no match. -@item -x@file{pattern} -@cindex @option{-x} (@code{gnatname}) -Excluded patterns. Using this switch, it is possible to exclude some files -that would match the name patterns. For example, -@smallexample -gnatname -x "*_nt.ada" "*.ada" -@end smallexample -@noindent -will look for Ada units in all files with the @file{.ada} extension, -except those whose names end with @file{_nt.ada}. +@table @asis + +@item @emph{Binder} + +This package specifies characteristics useful when invoking the binder either +directly via the @emph{gnat} driver or when using a builder such as +@emph{gnatmake} or @emph{gprbuild}. See @ref{15d,,Main Subprograms}. + +@item @emph{Builder} +This package specifies the compilation options used when building an +executable or a library for a project. Most of the options should be +set in one of @cite{Compiler}, @cite{Binder} or @cite{Linker} packages, +but there are some general options that should be defined in this +package. See @ref{15d,,Main Subprograms}, and @ref{162,,Executable File Names} in +particular. @end table -@node Examples of gnatname Usage -@section Examples of @code{gnatname} Usage -@smallexample -$ gnatname -c /home/me/names.adc -d sources "[a-z]*.ada*" -@end smallexample +@table @asis -@noindent -In this example, the directory @file{/home/me} must already exist -and be writable. In addition, the directory -@file{/home/me/sources} (specified by -@option{-d sources}) must exist and be readable. +@item @emph{Clean} -Note the optional spaces after @option{-c} and @option{-d}. +This package specifies the options used when cleaning a project or a project +tree using the tools @emph{gnatclean} or @emph{gprclean}. -@smallexample -$ gnatname -P/home/me/proj -x "*_nt_body.ada" - -dsources -dsources/plus -Dcommon_dirs.txt "body_*" "spec_*" -@end smallexample +@item @emph{Compiler} -Note that several switches @option{-d} may be used, -even in conjunction with one or several switches -@option{-D}. Several Naming Patterns and one excluded pattern -are used in this example. +This package specifies the compilation options used by the compiler for +each languages. See @ref{15e,,Tools Options in Project Files}. + +@item @emph{Cross_Reference} + +This package specifies the options used when calling the library tool +@emph{gnatxref} via the @emph{gnat} driver. Its attributes +@strong{Default_Switches} and @strong{Switches} have the same semantics as for the +package @cite{Builder}. +@end table -@c ***************************************** -@c * G N A T P r o j e c t M a n a g e r * -@c ***************************************** -@c ------ macros for projects.texi -@c These macros are needed when building the gprbuild documentation, but -@c should have no effect in the gnat user's guide -@macro CODESAMPLE{TXT} -@smallexample -@group -\TXT\ -@end group -@end smallexample -@end macro +@table @asis -@macro PROJECTFILE{TXT} -@CODESAMPLE{\TXT\} -@end macro +@item @emph{Finder} -@c simulates a newline when in a @CODESAMPLE -@macro NL{} -@end macro +This package specifies the options used when calling the search tool +@emph{gnatfind} via the @emph{gnat} driver. Its attributes +@strong{Default_Switches} and @strong{Switches} have the same semantics as for the +package @cite{Builder}. -@macro TIP{TXT} -@quotation -@noindent -\TXT\ -@end quotation -@end macro +@item @emph{Gnatls} -@macro TIPHTML{TXT} -\TXT\ -@end macro +This package specifies the options to use when invoking @emph{gnatls} +via the @emph{gnat} driver. +@end table -@macro IMPORTANT{TXT} -@quotation -@noindent -\TXT\ -@end quotation -@end macro -@macro NOTE{TXT} +@table @asis + +@item @emph{IDE} + +This package specifies the options used when starting an integrated +development environment, for instance @emph{GPS} or @emph{Gnatbench}. + +@item @emph{Install} + +This package specifies the options used when installing a project +with @emph{gprinstall}. See @ref{168,,Installation}. + +@item @emph{Linker} + +This package specifies the options used by the linker. +See @ref{15d,,Main Subprograms}. +@end table + + + +@table @asis + +@item @emph{Naming} + @quotation -@noindent -\TXT\ + +This package specifies the naming conventions that apply +to the source files in a project. In particular, these conventions are +used to automatically find all source files in the source directories, +or given a file name to find out its language for proper processing. +See @ref{14b,,Naming Schemes}. @end quotation -@end macro -@include projects.texi +@c only: PRO or GPL +@c +@c *Pretty_Printer* +@c This package specifies the options used when calling the formatting tool +@c *gnatpp* via the *gnat* driver. Its attributes +@c **Default_Switches** and **Switches** have the same semantics as for the +@c package `Builder`. -@c --------------------------------------------- -@c Tools Supporting Project Files -@c --------------------------------------------- +@item @emph{Remote} -@node Tools Supporting Project Files -@chapter Tools Supporting Project Files +This package is used by @emph{gprbuild} to describe how distributed +compilation should be done. -@noindent +@item @emph{Stack} -@menu -* gnatmake and Project Files:: -* The GNAT Driver and Project Files:: -@end menu +This package specifies the options used when calling the tool +@emph{gnatstack} via the @emph{gnat} driver. Its attributes +@strong{Default_Switches} and @strong{Switches} have the same semantics as for the +package @cite{Builder}. -@c --------------------------------------------- -@node gnatmake and Project Files -@section gnatmake and Project Files -@c --------------------------------------------- +@item @emph{Synchronize} -@noindent -This section covers several topics related to @command{gnatmake} and -project files: defining switches for @command{gnatmake} -and for the tools that it invokes; specifying configuration pragmas; -the use of the @code{Main} attribute; building and rebuilding library project -files. +This package specifies the options used when calling the tool +@emph{gnatsync} via the @emph{gnat} driver. +@end table -@menu -* Switches Related to Project Files:: -* Switches and Project Files:: -* Specifying Configuration Pragmas:: -* Project Files and Main Subprograms:: -* Library Project Files:: -@end menu +In its simplest form, a package may be empty: + +@example +project Simple is + package Builder is + end Builder; +end Simple; +@end example + +A package may contain @strong{attribute declarations}, +@strong{variable declarations} and @strong{case constructions}, as will be +described below. + +When there is ambiguity between a project name and a package name, +the name always designates the project. To avoid possible confusion, it is +always a good idea to avoid naming a project with one of the +names allowed for packages or any name that starts with @cite{gnat}. + +A package can also be defined by a @strong{renaming declaration}. The new package +renames a package declared in a different project file, and has the same +attributes as the package it renames. The name of the renamed package +must be the same as the name of the renaming package. The project must +contain a package declaration with this name, and the project +must appear in the context clause of the current project, or be its parent +project. It is not possible to add or override attributes to the renaming +project. If you need to do so, you should use an @strong{extending declaration} +(see below). + +Packages that are renamed in other project files often come from project files +that have no sources: they are just used as templates. Any modification in the +template will be reflected automatically in all the project files that rename +a package from the template. This is a very common way to share settings +between projects. + +Finally, a package can also be defined by an @strong{extending declaration}. This is +similar to a @strong{renaming declaration}, except that it is possible to add or +override attributes. + +@example +package_declaration ::= package_spec | package_renaming | package_extension +package_spec ::= + package <package_>simple_name is + @{simple_declarative_item@} + end package_identifier ; +package_renaming ::== + package <package_>simple_name renames <project_>simple_name.package_identifier ; +package_extension ::== + package <package_>simple_name extends <project_>simple_name.package_identifier is + @{simple_declarative_item@} + end package_identifier ; +@end example + +@node Expressions,External Values,Packages,Project File Reference +@anchor{gnat_ugn/gnat_project_manager expressions}@anchor{19b}@anchor{gnat_ugn/gnat_project_manager id42}@anchor{19c} +@subsection Expressions + + +An expression is any value that can be assigned to an attribute or a +variable. It is either a literal value, or a construct requiring runtime +computation by the project manager. In a project file, the computed value of +an expression is either a string or a list of strings. + +A string value is one of: + + +@itemize * + +@item +A literal string, for instance @cite{"comm/my_proj.gpr"} + +@item +The name of a variable that evaluates to a string (see @ref{155,,Variables}) + +@item +The name of an attribute that evaluates to a string (see @ref{152,,Attributes}) + +@item +An external reference (see @ref{154,,External Values}) + +@item +A concatenation of the above, as in @cite{"prefix_" & Var}. +@end itemize -@c --------------------------------------------- -@node Switches Related to Project Files -@subsection Switches Related to Project Files -@c --------------------------------------------- +A list of strings is one of the following: -@noindent -The following switches are used by GNAT tools that support project files: -@table @option +@itemize * -@item -P@var{project} -@cindex @option{-P} (any project-aware tool) -Indicates the name of a project file. This project file will be parsed with -the verbosity indicated by @option{-vP@emph{x}}, -if any, and using the external references indicated -by @option{-X} switches, if any. -There may zero, one or more spaces between @option{-P} and @var{project}. +@item +A parenthesized comma-separated list of zero or more string expressions, for +instance @cite{(File_Name@comma{} "gnat.adc"@comma{} File_Name & ".orig")} or @cite{()}. -There must be only one @option{-P} switch on the command line. +@item +The name of a variable that evaluates to a list of strings -Since the Project Manager parses the project file only after all the switches -on the command line are checked, the order of the switches -@option{-P}, -@option{-vP@emph{x}} -or @option{-X} is not significant. +@item +The name of an attribute that evaluates to a list of strings -@item -X@var{name=value} -@cindex @option{-X} (any project-aware tool) -Indicates that external variable @var{name} has the value @var{value}. -The Project Manager will use this value for occurrences of -@code{external(name)} when parsing the project file. +@item +A concatenation of a list of strings and a string (as defined above), for +instance @cite{("A"@comma{} "B") & "C"} -If @var{name} or @var{value} includes a space, then @var{name=value} should be -put between quotes. -@smallexample - -XOS=NT - -X"user=John Doe" -@end smallexample +@item +A concatenation of two lists of strings +@end itemize -Several @option{-X} switches can be used simultaneously. -If several @option{-X} switches specify the same -@var{name}, only the last one is used. +The following is the grammar for expressions + +@example +string_literal ::= "@{string_element@}" -- Same as Ada +string_expression ::= string_literal + | *variable_*name + | external_value + | attribute_reference + | ( string_expression @{ & string_expression @} ) +string_list ::= ( string_expression @{ , string_expression @} ) + | *string_variable*_name + | *string_*attribute_reference +term ::= string_expression | string_list +expression ::= term @{ & term @} -- Concatenation +@end example -An external variable specified with a @option{-X} switch -takes precedence over the value of the same name in the environment. +Concatenation involves strings and list of strings. As soon as a list of +strings is involved, the result of the concatenation is a list of strings. The +following Ada declarations show the existing operators: -@item -vP@emph{x} -@cindex @option{-vP} (any project-aware tool) -Indicates the verbosity of the parsing of GNAT project files. +@example +function "&" (X : String; Y : String) return String; +function "&" (X : String_List; Y : String) return String_List; +function "&" (X : String_List; Y : String_List) return String_List; +@end example -@option{-vP0} means Default; -@option{-vP1} means Medium; -@option{-vP2} means High. +Here are some specific examples: +@example +List := () & File_Name; -- One string in this list +List2 := List & (File_Name & ".orig"); -- Two strings +Big_List := List & Lists2; -- Three strings +Illegal := "gnat.adc" & List2; -- Illegal, must start with list +@end example -The default is Default: no output for syntactically correct -project files. -If several @option{-vP@emph{x}} switches are present, -only the last one is used. +@node External Values,Typed String Declaration,Expressions,Project File Reference +@anchor{gnat_ugn/gnat_project_manager external-values}@anchor{154}@anchor{gnat_ugn/gnat_project_manager id43}@anchor{19d} +@subsection External Values -@item -aP<dir> -@cindex @option{-aP} (any project-aware tool) -Add directory <dir> at the beginning of the project search path, in order, -after the current working directory. -@item -eL -@cindex @option{-eL} (any project-aware tool) -Follow all symbolic links when processing project files. +An external value is an expression whose value is obtained from the command +that invoked the processing of the current project file (typically a +@emph{gnatmake} or @emph{gprbuild} command). -@item --subdirs=<subdir> -@cindex @option{--subdirs=} (gnatmake and gnatclean) -This switch is recognized by @command{gnatmake} and @command{gnatclean}. It -indicate that the real directories (except the source directories) are the -subdirectories <subdir> of the directories specified in the project files. -This applies in particular to object directories, library directories and -exec directories. If the subdirectories do not exist, they are created -automatically. +There are two kinds of external values, one that returns a single string, and +one that returns a string list. + +The syntax of a single string external value is: -@end table +@example +external_value ::= *external* ( string_literal [, string_literal] ) +@end example -@c --------------------------------------------- -@node Switches and Project Files -@subsection Switches and Project Files -@c --------------------------------------------- +The first string_literal is the string to be used on the command line or +in the environment to specify the external value. The second string_literal, +if present, is the default to use if there is no specification for this +external value either on the command line or in the environment. -@noindent +Typically, the external value will either exist in the +environment variables +or be specified on the command line through the +@code{-X@emph{vbl}=@emph{value}} switch. If both +are specified, then the command line value is used, so that a user can more +easily override the value. + +The function @cite{external} always returns a string. It is an error if the +value was not found in the environment and no default was specified in the +call to @cite{external}. + +An external reference may be part of a string expression or of a string +list expression, and can therefore appear in a variable declaration or +an attribute declaration. + +Most of the time, this construct is used to initialize typed variables, which +are then used in @strong{case} constructions to control the value assigned to +attributes in various scenarios. Thus such variables are often called +@strong{scenario variables}. + +The syntax for a string list external value is: + +@example +external_value ::= *external_as_list* ( string_literal , string_literal ) +@end example + +The first string_literal is the string to be used on the command line or +in the environment to specify the external value. The second string_literal is +the separator between each component of the string list. + +If the external value does not exist in the environment or on the command line, +the result is an empty list. This is also the case, if the separator is an +empty string or if the external value is only one separator. + +Any separator at the beginning or at the end of the external value is +discarded. Then, if there is no separator in the external value, the result is +a string list with only one string. Otherwise, any string between the beginning +and the first separator, between two consecutive separators and between the +last separator and the end are components of the string list. + +@example +*external_as_list* ("SWITCHES", ",") +@end example + +If the external value is "-O2,-g", +the result is ("-O2", "-g"). -For each of the packages @code{Builder}, @code{Compiler}, @code{Binder}, and -@code{Linker}, you can specify a @code{Default_Switches} -attribute, a @code{Switches} attribute, or both; -as their names imply, these switch-related -attributes affect the switches that are used for each of these GNAT -components when -@command{gnatmake} is invoked. As will be explained below, these -component-specific switches precede -the switches provided on the @command{gnatmake} command line. +If the external value is ",-O2,-g,", +the result is also ("-O2", "-g"). -The @code{Default_Switches} attribute is an attribute -indexed by language name (case insensitive) whose value is a string list. -For example: +if the external value is "-gnatv", +the result is ("-gnatv"). -@smallexample @c projectfile -@group -@b{package} Compiler @b{is} - @b{for} Default_Switches ("Ada") - @b{use} ("-gnaty", - "-v"); -@b{end} Compiler; -@end group -@end smallexample +If the external value is ",,", the result is (""). -@noindent -The @code{Switches} attribute is indexed on a file name (which may or may -not be case sensitive, depending -on the operating system) whose value is a string list. For example: +If the external value is ",", the result is (), the empty string list. -@smallexample @c projectfile -@group -@b{package} Builder @b{is} - @b{for} Switches ("main1.adb") - @b{use} ("-O2"); - @b{for} Switches ("main2.adb") - @b{use} ("-g"); -@b{end} Builder; -@end group -@end smallexample - -@noindent -For the @code{Builder} package, the file names must designate source files -for main subprograms. For the @code{Binder} and @code{Linker} packages, the -file names must designate @file{ALI} or source files for main subprograms. -In each case just the file name without an explicit extension is acceptable. +@node Typed String Declaration,Variables,External Values,Project File Reference +@anchor{gnat_ugn/gnat_project_manager id44}@anchor{19e}@anchor{gnat_ugn/gnat_project_manager typed-string-declaration}@anchor{19f} +@subsection Typed String Declaration -For each tool used in a program build (@command{gnatmake}, the compiler, the -binder, and the linker), the corresponding package @dfn{contributes} a set of -switches for each file on which the tool is invoked, based on the -switch-related attributes defined in the package. -In particular, the switches -that each of these packages contributes for a given file @var{f} comprise: -@itemize @bullet -@item the value of attribute @code{Switches (@var{f})}, - if it is specified in the package for the given file, -@item otherwise, the value of @code{Default_Switches ("Ada")}, - if it is specified in the package. +A @strong{type declaration} introduces a discrete set of string literals. +If a string variable is declared to have this type, its value +is restricted to the given set of literals. These are the only named +types in project files. A string type may only be declared at the project +level, not inside a package. -@end itemize +@example +typed_string_declaration ::= + *type* *<typed_string_>*_simple_name *is* ( string_literal @{, string_literal@} ); +@end example -@noindent -If neither of these attributes is defined in the package, then the package does -not contribute any switches for the given file. +The string literals in the list are case sensitive and must all be different. +They may include any graphic characters allowed in Ada, including spaces. +Here is an example of a string type declaration: -When @command{gnatmake} is invoked on a file, the switches comprise -two sets, in the following order: those contributed for the file -by the @code{Builder} package; -and the switches passed on the command line. +@example +type OS is ("NT", "nt", "Unix", "GNU/Linux", "other OS"); +@end example -When @command{gnatmake} invokes a tool (compiler, binder, linker) on a file, -the switches passed to the tool comprise three sets, -in the following order: +Variables of a string type are called @strong{typed variables}; all other +variables are called @strong{untyped variables}. Typed variables are +particularly useful in @cite{case} constructions, to support conditional +attribute declarations. (See @ref{1a0,,Case Constructions}). -@enumerate -@item -the applicable switches contributed for the file -by the @code{Builder} package in the project file supplied on the command line; +A string type may be referenced by its name if it has been declared in the same +project file, or by an expanded name whose prefix is the name of the project +in which it is declared. -@item -those contributed for the file by the package (in the relevant project file -- -see below) corresponding to the tool; and +@node Variables,Case Constructions,Typed String Declaration,Project File Reference +@anchor{gnat_ugn/gnat_project_manager variables}@anchor{155}@anchor{gnat_ugn/gnat_project_manager id45}@anchor{1a1} +@subsection Variables -@item -the applicable switches passed on the command line. -@end enumerate -The term @emph{applicable switches} reflects the fact that -@command{gnatmake} switches may or may not be passed to individual -tools, depending on the individual switch. +@strong{Variables} store values (strings or list of strings) and can appear +as part of an expression. The declaration of a variable creates the +variable and assigns the value of the expression to it. The name of the +variable is available immediately after the assignment symbol, if you +need to reuse its old value to compute the new value. Before the completion +of its first declaration, the value of a variable defaults to the empty +string (""). -@command{gnatmake} may invoke the compiler on source files from different -projects. The Project Manager will use the appropriate project file to -determine the @code{Compiler} package for each source file being compiled. -Likewise for the @code{Binder} and @code{Linker} packages. +A @strong{typed} variable can be used as part of a @strong{case} expression to +compute the value, but it can only be declared once in the project file, +so that all case constructions see the same value for the variable. This +provides more consistency and makes the project easier to understand. +The syntax for its declaration is identical to the Ada syntax for an +object declaration. In effect, a typed variable acts as a constant. -As an example, consider the following package in a project file: +An @strong{untyped} variable can be declared and overridden multiple times +within the same project. It is declared implicitly through an Ada +assignment. The first declaration establishes the kind of the variable +(string or list of strings) and successive declarations must respect +the initial kind. Assignments are executed in the order in which they +appear, so the new value replaces the old one and any subsequent reference +to the variable uses the new value. -@smallexample @c projectfile -@group -@b{project} Proj1 @b{is} - @b{package} Compiler @b{is} - @b{for} Default_Switches ("Ada") - @b{use} ("-g"); - @b{for} Switches ("a.adb") - @b{use} ("-O1"); - @b{for} Switches ("b.adb") - @b{use} ("-O2", - "-gnaty"); - @b{end} Compiler; -@b{end} Proj1; -@end group -@end smallexample - -@noindent -If @command{gnatmake} is invoked with this project file, and it needs to -compile, say, the files @file{a.adb}, @file{b.adb}, and @file{c.adb}, then -@file{a.adb} will be compiled with the switch -@option{-O1}, -@file{b.adb} with switches -@option{-O2} -and @option{-gnaty}, -and @file{c.adb} with @option{-g}. +A variable may be declared at the project file level, or within a package. -The following example illustrates the ordering of the switches -contributed by different packages: +@example +typed_variable_declaration ::= + *<typed_variable_>*simple_name : *<typed_string_>*name := string_expression; -@smallexample @c projectfile -@group -@b{project} Proj2 @b{is} - @b{package} Builder @b{is} - @b{for} Switches ("main.adb") - @b{use} ("-g", - "-O1", - "-f"); - @b{end} Builder; -@end group - -@group - @b{package} Compiler @b{is} - @b{for} Switches ("main.adb") - @b{use} ("-O2"); - @b{end} Compiler; -@b{end} Proj2; -@end group -@end smallexample - -@noindent -If you issue the command: +variable_declaration ::= *<variable_>*simple_name := expression; +@end example -@smallexample - gnatmake -Pproj2 -O0 main -@end smallexample +Here are some examples of variable declarations: -@noindent -then the compiler will be invoked on @file{main.adb} with the following -sequence of switches +@example +This_OS : OS := external ("OS"); -- a typed variable declaration +That_OS := "GNU/Linux"; -- an untyped variable declaration -@smallexample - -g -O1 -O2 -O0 -@end smallexample +Name := "readme.txt"; +Save_Name := Name & ".saved"; -@noindent -with the last @option{-O} -switch having precedence over the earlier ones; -several other switches -(such as @option{-c}) are added implicitly. +Empty_List := (); +List_With_One_Element := ("-gnaty"); +List_With_Two_Elements := List_With_One_Element & "-gnatg"; +Long_List := ("main.ada", "pack1_.ada", "pack1.ada", "pack2_.ada"); +@end example -The switches -@option{-g} -and @option{-O1} are contributed by package -@code{Builder}, @option{-O2} is contributed -by the package @code{Compiler} -and @option{-O0} comes from the command line. +A @strong{variable reference} may take several forms: -The @option{-g} -switch will also be passed in the invocation of -@command{Gnatlink.} -A final example illustrates switch contributions from packages in different -project files: +@itemize * -@smallexample @c projectfile -@group -@b{project} Proj3 @b{is} - @b{for} Source_Files @b{use} ("pack.ads", "pack.adb"); - @b{package} Compiler @b{is} - @b{for} Default_Switches ("Ada") - @b{use} ("-gnata"); - @b{end} Compiler; -@b{end} Proj3; -@end group - -@group -@b{with} "Proj3"; -@b{project} Proj4 @b{is} - @b{for} Source_Files @b{use} ("foo_main.adb", "bar_main.adb"); - @b{package} Builder @b{is} - @b{for} Switches ("foo_main.adb") - @b{use} ("-s", - "-g"); - @b{end} Builder; -@b{end} Proj4; -@end group - -@group ---@i{ Ada source file:} -@b{with} Pack; -@b{procedure} Foo_Main @b{is} - @dots{} -@b{end} Foo_Main; -@end group -@end smallexample - -@noindent -If the command is -@smallexample -gnatmake -PProj4 foo_main.adb -cargs -gnato -@end smallexample - -@noindent -then the switches passed to the compiler for @file{foo_main.adb} are -@option{-g} (contributed by the package @code{Proj4.Builder}) and -@option{-gnato} (passed on the command line). -When the imported package @code{Pack} is compiled, the switches used -are @option{-g} from @code{Proj4.Builder}, -@option{-gnata} (contributed from package @code{Proj3.Compiler}, -and @option{-gnato} from the command line. - -When using @command{gnatmake} with project files, some switches or -arguments may be expressed as relative paths. As the working directory where -compilation occurs may change, these relative paths are converted to absolute -paths. For the switches found in a project file, the relative paths -are relative to the project file directory, for the switches on the command -line, they are relative to the directory where @command{gnatmake} is invoked. -The switches for which this occurs are: --I, --A, --L, --aO, --aL, --aI, as well as all arguments that are not switches (arguments to -switch --o, object files specified in package @code{Linker} or after --largs on the command line). The exception to this rule is the switch ---RTS= for which a relative path argument is never converted. +@item +The simple variable name, for a variable in the current package (if any) +or in the current project -@c --------------------------------------------- -@node Specifying Configuration Pragmas -@subsection Specifying Configuration Pragmas -@c --------------------------------------------- +@item +An expanded name, whose prefix is a context name. +@end itemize -@noindent -When using @command{gnatmake} with project files, if there exists a file -@file{gnat.adc} that contains configuration pragmas, this file will be -ignored. +A @strong{context} may be one of the following: -Configuration pragmas can be defined by means of the following attributes in -project files: @code{Global_Configuration_Pragmas} in package @code{Builder} -and @code{Local_Configuration_Pragmas} in package @code{Compiler}. -Both these attributes are single string attributes. Their values is the path -name of a file containing configuration pragmas. If a path name is relative, -then it is relative to the project directory of the project file where the -attribute is defined. +@itemize * -When compiling a source, the configuration pragmas used are, in order, -those listed in the file designated by attribute -@code{Global_Configuration_Pragmas} in package @code{Builder} of the main -project file, if it is specified, and those listed in the file designated by -attribute @code{Local_Configuration_Pragmas} in package @code{Compiler} of -the project file of the source, if it exists. +@item +The name of an existing package in the current project -@c --------------------------------------------- -@node Project Files and Main Subprograms -@subsection Project Files and Main Subprograms -@c --------------------------------------------- +@item +The name of an imported project of the current project -@noindent -When using a project file, you can invoke @command{gnatmake} -with one or several main subprograms, by specifying their source files on the -command line. +@item +The name of an ancestor project (i.e., a project extended by the current +project, either directly or indirectly) -@smallexample - gnatmake -Pprj main1.adb main2.adb main3.adb -@end smallexample +@item +An expanded name whose prefix is an imported/parent project name, and +whose selector is a package name in that project. +@end itemize -@noindent -Each of these needs to be a source file of the same project, except -when the switch -u is used. +@node Case Constructions,Attributes,Variables,Project File Reference +@anchor{gnat_ugn/gnat_project_manager id46}@anchor{1a2}@anchor{gnat_ugn/gnat_project_manager case-constructions}@anchor{1a0} +@subsection Case Constructions + + +A @strong{case} construction is used in a project file to effect conditional +behavior. Through this construction, you can set the value of attributes +and variables depending on the value previously assigned to a typed +variable. + +All choices in a choice list must be distinct. Unlike Ada, the choice +lists of all alternatives do not need to include all values of the type. +An @cite{others} choice must appear last in the list of alternatives. + +The syntax of a @cite{case} construction is based on the Ada case construction +(although the @cite{null} declaration for empty alternatives is optional). + +The case expression must be a string variable, either typed or not, whose value +is often given by an external reference (see @ref{154,,External Values}). + +Each alternative starts with the reserved word @cite{when}, either a list of +literal strings separated by the @cite{"|"} character or the reserved word +@cite{others}, and the @cite{"=>"} token. +When the case expression is a typed string variable, each literal string must +belong to the string type that is the type of the case variable. +After each @cite{=>}, there are zero or more declarations. The only +declarations allowed in a case construction are other case constructions, +attribute declarations and variable declarations. String type declarations and +package declarations are not allowed. Variable declarations are restricted to +variables that have already been declared before the case construction. + +@example +case_construction ::= + *case* *<variable_>*name *is* @{case_item@} *end case* ; + +case_item ::= + *when* discrete_choice_list => + @{case_declaration + | attribute_declaration + | variable_declaration + | empty_declaration@} + +discrete_choice_list ::= string_literal @{| string_literal@} | *others* +@end example + +Here is a typical example, with a typed string variable: + +@example +project MyProj is + type OS_Type is ("GNU/Linux", "Unix", "NT", "VMS"); + OS : OS_Type := external ("OS", "GNU/Linux"); + + package Compiler is + case OS is + when "GNU/Linux" | "Unix" => + for Switches ("Ada") + use ("-gnath"); + when "NT" => + for Switches ("Ada") + use ("-gnatP"); + when others => + null; + end case; + end Compiler; +end MyProj; +@end example + +@node Attributes,,Case Constructions,Project File Reference +@anchor{gnat_ugn/gnat_project_manager id47}@anchor{1a3}@anchor{gnat_ugn/gnat_project_manager attributes}@anchor{152} +@subsection Attributes + + +A project (and its packages) may have @strong{attributes} that define +the project's properties. Some attributes have values that are strings; +others have values that are string lists. + +@example +attribute_declaration ::= + simple_attribute_declaration | indexed_attribute_declaration + +simple_attribute_declaration ::= *for* attribute_designator *use* expression ; + +indexed_attribute_declaration ::= + *for* *<indexed_attribute_>*simple_name ( string_literal) *use* expression ; + +attribute_designator ::= + *<simple_attribute_>*simple_name + | *<indexed_attribute_>*simple_name ( string_literal ) +@end example + +There are two categories of attributes: @strong{simple attributes} +and @strong{indexed attributes}. +Each simple attribute has a default value: the empty string (for string +attributes) and the empty list (for string list attributes). +An attribute declaration defines a new value for an attribute, and overrides +the previous value. The syntax of a simple attribute declaration is similar to +that of an attribute definition clause in Ada. + +Some attributes are indexed. These attributes are mappings whose +domain is a set of strings. They are declared one association +at a time, by specifying a point in the domain and the corresponding image +of the attribute. +Like untyped variables and simple attributes, indexed attributes +may be declared several times. Each declaration supplies a new value for the +attribute, and replaces the previous setting. + +Here are some examples of attribute declarations: + +@example +-- simple attributes +for Object_Dir use "objects"; +for Source_Dirs use ("units", "test/drivers"); + +-- indexed attributes +for Body ("main") use "Main.ada"; +for Switches ("main.ada") + use ("-v", "-gnatv"); +for Switches ("main.ada") use Builder'Switches ("main.ada") & "-g"; + +-- indexed attributes copy (from package Builder in project Default) +-- The package name must always be specified, even if it is the current +-- package. +for Default_Switches use Default.Builder'Default_Switches; +@end example + +Attributes references may appear anywhere in expressions, and are used +to retrieve the value previously assigned to the attribute. If an attribute +has not been set in a given package or project, its value defaults to the +empty string or the empty list, with some exceptions. + +@example +attribute_reference ::= + attribute_prefix ' *<simple_attribute>_*simple_name [ (string_literal) ] +attribute_prefix ::= *project* + | *<project_>*simple_name + | package_identifier + | *<project_>*simple_name . package_identifier +@end example + +Examples are: + +@example +<project>'Object_Dir +Naming'Dot_Replacement +Imported_Project'Source_Dirs +Imported_Project.Naming'Casing +Builder'Default_Switches ("Ada") +@end example + +The exceptions to the empty defaults are: + + +@itemize * + +@item +Object_Dir: default is "." + +@item +Exec_Dir: default is 'Object_Dir, that is the value of attribute +Object_Dir in the same project, declared or defaulted. + +@item +Source_Dirs: default is (".") +@end itemize -When -u is not used, all the mains need to be sources of the -same project, one of the project in the tree rooted at the project specified -on the command line. The package @code{Builder} of this common project, the -"main project" is the one that is considered by @command{gnatmake}. +The prefix of an attribute may be: -When -u is used, the specified source files may be in projects -imported directly or indirectly by the project specified on the command line. -Note that if such a source file is not part of the project specified on the -command line, the switches found in package @code{Builder} of the -project specified on the command line, if any, that are transmitted -to the compiler will still be used, not those found in the project file of -the source file. -When using a project file, you can also invoke @command{gnatmake} without -explicitly specifying any main, and the effect depends on whether you have -defined the @code{Main} attribute. This attribute has a string list value, -where each element in the list is the name of a source file (the file -extension is optional) that contains a unit that can be a main subprogram. +@itemize * -If the @code{Main} attribute is defined in a project file as a non-empty -string list and the switch @option{-u} is not used on the command -line, then invoking @command{gnatmake} with this project file but without any -main on the command line is equivalent to invoking @command{gnatmake} with all -the file names in the @code{Main} attribute on the command line. +@item +@cite{project} for an attribute of the current project -Example: -@smallexample @c projectfile -@group - @b{project} Prj @b{is} - @b{for} Main @b{use} ("main1.adb", "main2.adb", "main3.adb"); - @b{end} Prj; -@end group -@end smallexample - -@noindent -With this project file, @code{"gnatmake -Pprj"} -is equivalent to -@code{"gnatmake -Pprj main1.adb main2.adb main3.adb"}. +@item +The name of an existing package of the current project -When the project attribute @code{Main} is not specified, or is specified -as an empty string list, or when the switch @option{-u} is used on the command -line, then invoking @command{gnatmake} with no main on the command line will -result in all immediate sources of the project file being checked, and -potentially recompiled. Depending on the presence of the switch @option{-u}, -sources from other project files on which the immediate sources of the main -project file depend are also checked and potentially recompiled. In other -words, the @option{-u} switch is applied to all of the immediate sources of the -main project file. +@item +The name of an imported project -When no main is specified on the command line and attribute @code{Main} exists -and includes several mains, or when several mains are specified on the -command line, the default switches in package @code{Builder} will -be used for all mains, even if there are specific switches -specified for one or several mains. +@item +The name of a parent project that is extended by the current project -But the switches from package @code{Binder} or @code{Linker} will be -the specific switches for each main, if they are specified. +@item +An expanded name whose prefix is imported/parent project name, +and whose selector is a package name +@end itemize -@c --------------------------------------------- -@node Library Project Files -@subsection Library Project Files -@c --------------------------------------------- +In the following sections, all predefined attributes are succinctly described, +first the project level attributes, that is those attributes that are not in a +package, then the attributes in the different packages. -@noindent -When @command{gnatmake} is invoked with a main project file that is a library -project file, it is not allowed to specify one or more mains on the command -line. +It is possible for different tools to dynamically create new packages with +attributes, or new attributes in predefined packages. These attributes are +not documented here. + +The attributes under Configuration headings are usually found only in +configuration project files. + +The characteristics of each attribute are indicated as follows: + + +@itemize * + +@item +@strong{Type of value} + +The value of an attribute may be a single string, indicated by the word +"single", or a string list, indicated by the word "list". + +@item +@strong{Read-only} + +When the attribute is read-only, that is when it is not allowed to declare +the attribute, this is indicated by the words "read-only". + +@item +@strong{Optional index} + +If it is allowed in the value of the attribute (both single and list) to have +an optional index, this is indicated by the words "optional index". + +@item +@strong{Indexed attribute} + +When it is an indexed attribute, this is indicated by the word "indexed". + +@item +@strong{Case-sensitivity of the index} + +For an indexed attribute, if the index is case-insensitive, this is indicated +by the words "case-insensitive index". -When a library project file is specified, switches -b and --l have special meanings. +@item +@strong{File name index} -@itemize @bullet -@item -b is only allowed for stand-alone libraries. It indicates - to @command{gnatmake} that @command{gnatbind} should be invoked for the - library. +For an indexed attribute, when the index is a file name, this is indicated by +the words "file name index". The index may or may not be case-sensitive, +depending on the platform. -@item -l may be used for all library projects. It indicates - to @command{gnatmake} that the binder generated file should be compiled - (in the case of a stand-alone library) and that the library should be built. +@item +@strong{others allowed in index} + +For an indexed attribute, if it is allowed to use @strong{others} as the index, +this is indicated by the words "others allowed". + +When @strong{others} is used as the index of an indexed attribute, the value of +the attribute indexed by @strong{others} is used when no other index would apply. @end itemize -@c --------------------------------------------- -@node The GNAT Driver and Project Files -@section The GNAT Driver and Project Files -@c --------------------------------------------- +@menu +* Project Level Attributes:: +* Package Binder Attributes:: +* Package Builder Attributes:: +* Package Clean Attributes:: +* Package Compiler Attributes:: +* Package Cross_Reference Attributes:: +* Package Finder Attributes:: +* Package gnatls Attributes:: +* Package IDE Attributes:: +* Package Install Attributes:: +* Package Linker Attributes:: +* Package Naming Attributes:: +* Package Remote Attributes:: +* Package Stack Attributes:: +* Package Synchronize Attributes:: -@noindent -A number of GNAT tools, other than @command{gnatmake} -can benefit from project files: -(@command{gnatbind}, -@ifclear FSFEDITION -@command{gnatcheck}, -@end ifclear -@command{gnatclean}, -@ifclear FSFEDITION -@command{gnatelim}, -@end ifclear -@command{gnatfind}, -@command{gnatlink}, -@command{gnatls}, -@ifclear FSFEDITION -@command{gnatmetric}, -@command{gnatpp}, -@command{gnatstub}, -@end ifclear -and @command{gnatxref}). However, none of these tools can be invoked -directly with a project file switch (@option{-P}). -They must be invoked through the @command{gnat} driver. - -The @command{gnat} driver is a wrapper that accepts a number of commands and -calls the corresponding tool. It was designed initially for VMS platforms (to -convert VMS qualifiers to Unix-style switches), but it is now available on all -GNAT platforms. +@end menu -On non-VMS platforms, the @command{gnat} driver accepts the following commands -(case insensitive): +@node Project Level Attributes,Package Binder Attributes,,Attributes +@anchor{gnat_ugn/gnat_project_manager project-level-attributes}@anchor{1a4}@anchor{gnat_ugn/gnat_project_manager id48}@anchor{1a5} +@subsubsection Project Level Attributes + + + +@itemize * + +@item +@strong{General} + + +@itemize * -@itemize @bullet -@item BIND to invoke @command{gnatbind} -@item CHOP to invoke @command{gnatchop} -@item CLEAN to invoke @command{gnatclean} -@item COMP or COMPILE to invoke the compiler -@ifclear FSFEDITION -@item ELIM to invoke @command{gnatelim} -@end ifclear -@item FIND to invoke @command{gnatfind} -@item KR or KRUNCH to invoke @command{gnatkr} -@item LINK to invoke @command{gnatlink} -@item LS or LIST to invoke @command{gnatls} -@item MAKE to invoke @command{gnatmake} -@item NAME to invoke @command{gnatname} -@item PREP or PREPROCESS to invoke @command{gnatprep} -@ifclear FSFEDITION -@item PP or PRETTY to invoke @command{gnatpp} -@item METRIC to invoke @command{gnatmetric} -@item STUB to invoke @command{gnatstub} -@end ifclear -@item XREF to invoke @command{gnatxref} +@item +@strong{Name}: single, read-only +The name of the project. + +@item +@strong{Project_Dir}: single, read-only + +The path name of the project directory. + +@item +@strong{Main}: list, optional index + +The list of main sources for the executables. + +@item +@strong{Languages}: list + +The list of languages of the sources of the project. + +@item +@strong{Roots}: list, indexed, file name index + +The index is the file name of an executable source. Indicates the list of units +from the main project that need to be bound and linked with their closures +with the executable. The index is either a file name, a language name or "*". +The roots for an executable source are those in @strong{Roots} with an index that +is the executable source file name, if declared. Otherwise, they are those in +@strong{Roots} with an index that is the language name of the executable source, +if present. Otherwise, they are those in @strong{Roots ("*")}, if declared. If none +of these three possibilities are declared, then there are no roots for the +executable source. + +@item +@strong{Externally_Built}: single + +Indicates if the project is externally built. +Only case-insensitive values allowed are "true" and "false", the default. @end itemize -@noindent -(note that the compiler is invoked using the command -@command{gnatmake -f -u -c}). +@item +@strong{Directories} -On non-VMS platforms, between @command{gnat} and the command, two -special switches may be used: -@itemize @bullet -@item @command{-v} to display the invocation of the tool. -@item @command{-dn} to prevent the @command{gnat} driver from removing - the temporary files it has created. These temporary files are - configuration files and temporary file list files. +@itemize * + +@item +@strong{Object_Dir}: single + +Indicates the object directory for the project. + +@item +@strong{Exec_Dir}: single + +Indicates the exec directory for the project, that is the directory where the +executables are. + +@item +@strong{Source_Dirs}: list +The list of source directories of the project. + +@item +@strong{Inherit_Source_Path}: list, indexed, case-insensitive index + +Index is a language name. Value is a list of language names. Indicates that +in the source search path of the index language the source directories of +the languages in the list should be included. + +Example: + +@example +for Inherit_Source_Path ("C++") use ("C"); +@end example + +@item +@strong{Exclude_Source_Dirs}: list + +The list of directories that are included in Source_Dirs but are not source +directories of the project. + +@item +@strong{Ignore_Source_Sub_Dirs}: list + +Value is a list of simple names for subdirectories that are removed from the +list of source directories, including theur subdirectories. @end itemize -@noindent -The command may be followed by switches and arguments for the invoked -tool. +@item +@strong{Source Files} -@smallexample - gnat bind -C main.ali - gnat ls -a main - gnat chop foo.txt -@end smallexample -@noindent -Switches may also be put in text files, one switch per line, and the text -files may be specified with their path name preceded by '@@'. +@itemize * -@smallexample - gnat bind @@args.txt main.ali -@end smallexample - -@noindent -In addition, for commands BIND, COMP or COMPILE, FIND, -@ifclear FSFEDITION -ELIM, -@end ifclear -LS or LIST, LINK, -@ifclear FSFEDITION -METRIC, -PP or PRETTY, -STUB, -@end ifclear -and XREF, the project file related switches -(@option{-P}, -@option{-X} and -@option{-vPx}) may be used in addition to -the switches of the invoking tool. - -@ifclear FSFEDITION -When GNAT PP or GNAT PRETTY is used with a project file, but with no source -specified on the command line, it invokes @command{gnatpp} with all -the immediate sources of the specified project file. -@end ifclear - -@ifclear FSFEDITION -When GNAT METRIC is used with a project file, but with no source -specified on the command line, it invokes @command{gnatmetric} -with all the immediate sources of the specified project file and with -@option{-d} with the parameter pointing to the object directory -of the project. -@end ifclear - -@ifclear FSFEDITION -In addition, when GNAT PP, GNAT PRETTY or GNAT METRIC is used with -a project file, no source is specified on the command line and -switch -U is specified on the command line, then -the underlying tool (gnatpp or -gnatmetric) is invoked for all sources of all projects, -not only for the immediate sources of the main project. -(-U stands for Universal or Union of the project files of the project tree) -@end ifclear +@item +@strong{Source_Files}: list -For each of the following commands, there is optionally a corresponding -package in the main project. +Value is a list of source file simple names. + +@item +@strong{Locally_Removed_Files}: list -@itemize @bullet -@item package @code{Binder} for command BIND (invoking @code{gnatbind}) +Obsolescent. Equivalent to Excluded_Source_Files. -@ifclear FSFEDITION -@item package @code{Check} for command CHECK (invoking - @code{gnatcheck}) -@end ifclear +@item +@strong{Excluded_Source_Files}: list -@item package @code{Compiler} for command COMP or COMPILE (invoking the compiler) +Value is a list of simple file names that are not sources of the project. +Allows to remove sources that are inherited or found in the source directories +and that match the naming scheme. -@item package @code{Cross_Reference} for command XREF (invoking - @code{gnatxref}) +@item +@strong{Source_List_File}: single -@ifclear FSFEDITION -@item package @code{Eliminate} for command ELIM (invoking - @code{gnatelim}) -@end ifclear +Value is a text file name that contains a list of source file simple names, +one on each line. -@item package @code{Finder} for command FIND (invoking @code{gnatfind}) +@item +@strong{Excluded_Source_List_File}: single -@item package @code{Gnatls} for command LS or LIST (invoking @code{gnatls}) +Value is a text file name that contains a list of file simple names that +are not sources of the project. -@ifclear FSFEDITION -@item package @code{Gnatstub} for command STUB - (invoking @code{gnatstub}) -@end ifclear +@item +@strong{Interfaces}: list -@item package @code{Linker} for command LINK (invoking @code{gnatlink}) +Value is a list of file names that constitutes the interfaces of the project. +@end itemize + +@item +@strong{Aggregate Projects} + + +@itemize * -@ifclear FSFEDITION -@item package @code{Check} for command CHECK - (invoking @code{gnatcheck}) -@end ifclear +@item +@strong{Project_Files}: list -@ifclear FSFEDITION -@item package @code{Metrics} for command METRIC - (invoking @code{gnatmetric}) -@end ifclear +Value is the list of aggregated projects. -@ifclear FSFEDITION -@item package @code{Pretty_Printer} for command PP or PRETTY - (invoking @code{gnatpp}) -@end ifclear +@item +@strong{Project_Path}: list +Value is a list of directories that are added to the project search path when +looking for the aggregated projects. + +@item +@strong{External}: single, indexed + +Index is the name of an external reference. Value is the value of the +external reference to be used when parsing the aggregated projects. @end itemize -@noindent -Package @code{Gnatls} has a unique attribute @code{Switches}, -a simple variable with a string list value. It contains switches -for the invocation of @code{gnatls}. - -@smallexample @c projectfile -@group -@b{project} Proj1 @b{is} - @b{package} gnatls @b{is} - @b{for} Switches - @b{use} ("-a", - "-v"); - @b{end} gnatls; -@b{end} Proj1; -@end group -@end smallexample +@item +@strong{Libraries} -@noindent -All other packages have two attribute @code{Switches} and -@code{Default_Switches}. -@code{Switches} is an indexed attribute, indexed by the -source file name, that has a string list value: the switches to be -used when the tool corresponding to the package is invoked for the specific -source file. +@itemize * -@code{Default_Switches} is an attribute, -indexed by the programming language that has a string list value. -@code{Default_Switches ("Ada")} contains the -switches for the invocation of the tool corresponding -to the package, except if a specific @code{Switches} attribute -is specified for the source file. +@item +@strong{Library_Dir}: single -@smallexample @c projectfile -@group -@b{project} Proj @b{is} +Value is the name of the library directory. This attribute needs to be +declared for each library project. - @b{for} Source_Dirs @b{use} ("**"); +@item +@strong{Library_Name}: single - @b{package} gnatls @b{is} - @b{for} Switches @b{use} - ("-a", - "-v"); - @b{end} gnatls; -@end group -@group +Value is the name of the library. This attribute needs to be declared or +inherited for each library project. - @b{package} Compiler @b{is} - @b{for} Default_Switches ("Ada") - @b{use} ("-gnatv", - "-gnatwa"); - @b{end} Binder; -@end group -@group +@item +@strong{Library_Kind}: single - @b{package} Binder @b{is} - @b{for} Default_Switches ("Ada") - @b{use} ("-C", - "-e"); - @b{end} Binder; -@end group -@group - - @b{package} Linker @b{is} - @b{for} Default_Switches ("Ada") - @b{use} ("-C"); - @b{for} Switches ("main.adb") - @b{use} ("-C", - "-v", - "-v"); - @b{end} Linker; -@end group -@group +Specifies the kind of library: static library (archive) or shared library. +Case-insensitive values must be one of "static" for archives (the default) or +"dynamic" or "relocatable" for shared libraries. - @b{package} Finder @b{is} - @b{for} Default_Switches ("Ada") - @b{use} ("-a", - "-f"); - @b{end} Finder; -@end group -@group +@item +@strong{Library_Version}: single - @b{package} Cross_Reference @b{is} - @b{for} Default_Switches ("Ada") - @b{use} ("-a", - "-f", - "-d", - "-u"); - @b{end} Cross_Reference; -@b{end} Proj; -@end group -@end smallexample +Value is the name of the library file. -@noindent -With the above project file, commands such as +@item +@strong{Library_Interface}: list -@smallexample - gnat comp -Pproj main - gnat ls -Pproj main - gnat xref -Pproj main - gnat bind -Pproj main.ali - gnat link -Pproj main.ali -@end smallexample +Value is the list of unit names that constitutes the interfaces +of a Stand-Alone Library project. -@noindent -will set up the environment properly and invoke the tool with the switches -found in the package corresponding to the tool: -@code{Default_Switches ("Ada")} for all tools, -except @code{Switches ("main.adb")} -for @code{gnatlink}. -@ifclear FSFEDITION -It is also possible to invoke some of the tools, -(@code{gnatcheck}, -@code{gnatmetric}, -and @code{gnatpp}) -on a set of project units thanks to the combination of the switches -@option{-P}, @option{-U} and possibly the main unit when one is interested -in its closure. For instance, -@smallexample -gnat metric -Pproj -@end smallexample - -@noindent -will compute the metrics for all the immediate units of project -@code{proj}. -@smallexample -gnat metric -Pproj -U -@end smallexample - -@noindent -will compute the metrics for all the units of the closure of projects -rooted at @code{proj}. -@smallexample -gnat metric -Pproj -U main_unit -@end smallexample - -@noindent -will compute the metrics for the closure of units rooted at -@code{main_unit}. This last possibility relies implicitly -on @command{gnatbind}'s option @option{-R}. But if the argument files for the -tool invoked by the @command{gnat} driver are explicitly specified -either directly or through the tool @option{-files} option, then the tool -is called only for these explicitly specified files. -@end ifclear - -@c ***************************************** -@c * Cross-referencing tools -@c ***************************************** - -@node The Cross-Referencing Tools gnatxref and gnatfind -@chapter The Cross-Referencing Tools @code{gnatxref} and @code{gnatfind} -@findex gnatxref -@findex gnatfind - -@noindent -The compiler generates cross-referencing information (unless -you set the @samp{-gnatx} switch), which are saved in the @file{.ali} files. -This information indicates where in the source each entity is declared and -referenced. Note that entities in package Standard are not included, but -entities in all other predefined units are included in the output. +@item +@strong{Library_Standalone}: single -Before using any of these two tools, you need to compile successfully your -application, so that GNAT gets a chance to generate the cross-referencing -information. +Specifies if a Stand-Alone Library (SAL) is encapsulated or not. +Only authorized case-insensitive values are "standard" for non encapsulated +SALs, "encapsulated" for encapsulated SALs or "no" for non SAL library project. -The two tools @code{gnatxref} and @code{gnatfind} take advantage of this -information to provide the user with the capability to easily locate the -declaration and references to an entity. These tools are quite similar, -the difference being that @code{gnatfind} is intended for locating -definitions and/or references to a specified entity or entities, whereas -@code{gnatxref} is oriented to generating a full report of all -cross-references. +@item +@strong{Library_Encapsulated_Options}: list -To use these tools, you must not compile your application using the -@option{-gnatx} switch on the @command{gnatmake} command line -(@pxref{The GNAT Make Program gnatmake}). Otherwise, cross-referencing -information will not be generated. +Value is a list of options that need to be used when linking an encapsulated +Stand-Alone Library. -Note: to invoke @code{gnatxref} or @code{gnatfind} with a project file, -use the @code{gnat} driver (see @ref{The GNAT Driver and Project Files}). +@item +@strong{Library_Encapsulated_Supported}: single -@menu -* Switches for gnatxref:: -* Switches for gnatfind:: -* Project Files for gnatxref and gnatfind:: -* Regular Expressions in gnatfind and gnatxref:: -* Examples of gnatxref Usage:: -* Examples of gnatfind Usage:: -@end menu +Indicates if encapsulated Stand-Alone Libraries are supported. Only +authorized case-insensitive values are "true" and "false" (the default). -@node Switches for gnatxref -@section @code{gnatxref} Switches +@item +@strong{Library_Auto_Init}: single -@noindent -The command invocation for @code{gnatxref} is: -@smallexample -@c $ gnatxref @ovar{switches} @var{sourcefile1} @r{[}@var{sourcefile2} @dots{}@r{]} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatxref @r{[}@var{switches}@r{]} @var{sourcefile1} @r{[}@var{sourcefile2} @dots{}@r{]} -@end smallexample +Indicates if a Stand-Alone Library is auto-initialized. Only authorized +case-insentive values are "true" and "false". -@noindent -where +@item +@strong{Leading_Library_Options}: list -@table @var -@item sourcefile1 -@itemx sourcefile2 -identifies the source files for which a report is to be generated. The -``with''ed units will be processed too. You must provide at least one file. +Value is a list of options that are to be used at the beginning of +the command line when linking a shared library. -These file names are considered to be regular expressions, so for instance -specifying @file{source*.adb} is the same as giving every file in the current -directory whose name starts with @file{source} and whose extension is -@file{adb}. +@item +@strong{Library_Options}: list -You shouldn't specify any directory name, just base names. @command{gnatxref} -and @command{gnatfind} will be able to locate these files by themselves using -the source path. If you specify directories, no result is produced. +Value is a list of options that are to be used when linking a shared library. -@end table +@item +@strong{Library_Rpath_Options}: list, indexed, case-insensitive index -@noindent -The switches can be: -@table @option -@c !sort! -@item --version -@cindex @option{--version} @command{gnatxref} -Display Copyright and version, then exit disregarding all other options. +Index is a language name. Value is a list of options for an invocation of the +compiler of the language. This invocation is done for a shared library project +with sources of the language. The output of the invocation is the path name +of a shared library file. The directory name is to be put in the run path +option switch when linking the shared library for the project. -@item --help -@cindex @option{--help} @command{gnatxref} -If @option{--version} was not used, display usage, then exit disregarding -all other options. +@item +@strong{Library_Src_Dir}: single -@item -a -@cindex @option{-a} (@command{gnatxref}) -If this switch is present, @code{gnatfind} and @code{gnatxref} will parse -the read-only files found in the library search path. Otherwise, these files -will be ignored. This option can be used to protect Gnat sources or your own -libraries from being parsed, thus making @code{gnatfind} and @code{gnatxref} -much faster, and their output much smaller. Read-only here refers to access -or permissions status in the file system for the current user. +Value is the name of the directory where copies of the sources of the +interfaces of a Stand-Alone Library are to be copied. -@item -aIDIR -@cindex @option{-aIDIR} (@command{gnatxref}) -When looking for source files also look in directory DIR. The order in which -source file search is undertaken is the same as for @command{gnatmake}. +@item +@strong{Library_ALI_Dir}: single -@item -aODIR -@cindex @option{-aODIR} (@command{gnatxref}) -When searching for library and object files, look in directory -DIR. The order in which library files are searched is the same as for -@command{gnatmake}. +Value is the name of the directory where the ALI files of the interfaces +of a Stand-Alone Library are to be copied. When this attribute is not declared, +the directory is the library directory. -@item -nostdinc -@cindex @option{-nostdinc} (@command{gnatxref}) -Do not look for sources in the system default directory. +@item +@strong{Library_gcc}: single -@item -nostdlib -@cindex @option{-nostdlib} (@command{gnatxref}) -Do not look for library files in the system default directory. +Obsolescent attribute. Specify the linker driver used to link a shared library. +Use instead attribute Linker'Driver. -@item --ext=@var{extension} -@cindex @option{--ext} (@command{gnatxref}) -Specify an alternate ali file extension. The default is @code{ali} and other -extensions (e.g. @code{gli} for C/C++ sources when using @option{-fdump-xref}) -may be specified via this switch. Note that if this switch overrides the -default, which means that only the new extension will be considered. +@item +@strong{Library_Symbol_File}: single -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gnatxref}) -Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). +Value is the name of the library symbol file. -@item -d -@cindex @option{-d} (@command{gnatxref}) -If this switch is set @code{gnatxref} will output the parent type -reference for each matching derived types. +@item +@strong{Library_Symbol_Policy}: single -@item -f -@cindex @option{-f} (@command{gnatxref}) -If this switch is set, the output file names will be preceded by their -directory (if the file was found in the search path). If this switch is -not set, the directory will not be printed. +Indicates the symbol policy kind. Only authorized case-insensitive values are +"autonomous", "default", "compliant", "controlled" or "direct". -@item -g -@cindex @option{-g} (@command{gnatxref}) -If this switch is set, information is output only for library-level -entities, ignoring local entities. The use of this switch may accelerate -@code{gnatfind} and @code{gnatxref}. +@item +@strong{Library_Reference_Symbol_File}: single -@item -IDIR -@cindex @option{-IDIR} (@command{gnatxref}) -Equivalent to @samp{-aODIR -aIDIR}. +Value is the name of the reference symbol file. +@end itemize -@item -pFILE -@cindex @option{-pFILE} (@command{gnatxref}) -Specify a project file to use @xref{GNAT Project Manager}. -If you need to use the @file{.gpr} -project files, you should use gnatxref through the GNAT driver -(@command{gnat xref -Pproject}). +@item +@strong{Configuration - General} -By default, @code{gnatxref} and @code{gnatfind} will try to locate a -project file in the current directory. -If a project file is either specified or found by the tools, then the content -of the source directory and object directory lines are added as if they -had been specified respectively by @samp{-aI} -and @samp{-aO}. -@item -u -Output only unused symbols. This may be really useful if you give your -main compilation unit on the command line, as @code{gnatxref} will then -display every unused entity and 'with'ed package. +@itemize * -@item -v -Instead of producing the default output, @code{gnatxref} will generate a -@file{tags} file that can be used by vi. For examples how to use this -feature, see @ref{Examples of gnatxref Usage}. The tags file is output -to the standard output, thus you will have to redirect it to a file. +@item +@strong{Default_Language}: single -@end table +Value is the case-insensitive name of the language of a project when attribute +Languages is not specified. -@noindent -All these switches may be in any order on the command line, and may even -appear after the file names. They need not be separated by spaces, thus -you can say @samp{gnatxref -ag} instead of -@samp{gnatxref -a -g}. +@item +@strong{Run_Path_Option}: list -@node Switches for gnatfind -@section @code{gnatfind} Switches +Value is the list of switches to be used when specifying the run path option +in an executable. -@noindent -The command line for @code{gnatfind} is: +@item +@strong{Run_Path_Origin}: single -@smallexample -@c $ gnatfind @ovar{switches} @var{pattern}@r{[}:@var{sourcefile}@r{[}:@var{line}@r{[}:@var{column}@r{]]]} -@c @r{[}@var{file1} @var{file2} @dots{}] -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatfind @r{[}@var{switches}@r{]} @var{pattern}@r{[}:@var{sourcefile}@r{[}:@var{line}@r{[}:@var{column}@r{]]]} - @r{[}@var{file1} @var{file2} @dots{}@r{]} -@end smallexample +Value is the the string that may replace the path name of the executable +directory in the run path options. -@noindent -where +@item +@strong{Separate_Run_Path_Options}: single -@table @var -@item pattern -An entity will be output only if it matches the regular expression found -in @var{pattern}, see @ref{Regular Expressions in gnatfind and gnatxref}. +Indicates if there may be several run path options specified when linking an +executable. Only authorized case-insensitive values are "true" or "false" (the +default). -Omitting the pattern is equivalent to specifying @samp{*}, which -will match any entity. Note that if you do not provide a pattern, you -have to provide both a sourcefile and a line. +@item +@strong{Toolchain_Version}: single, indexed, case-insensitive index -Entity names are given in Latin-1, with uppercase/lowercase equivalence -for matching purposes. At the current time there is no support for -8-bit codes other than Latin-1, or for wide characters in identifiers. +Index is a language name. Specify the version of a toolchain for a language. -@item sourcefile -@code{gnatfind} will look for references, bodies or declarations -of symbols referenced in @file{@var{sourcefile}}, at line @var{line} -and column @var{column}. See @ref{Examples of gnatfind Usage} -for syntax examples. +@item +@strong{Toolchain_Description}: single, indexed, case-insensitive index -@item line -is a decimal integer identifying the line number containing -the reference to the entity (or entities) to be located. +Obsolescent. No longer used. -@item column -is a decimal integer identifying the exact location on the -line of the first character of the identifier for the -entity reference. Columns are numbered from 1. +@item +@strong{Object_Generated}: single, indexed, case-insensitive index -@item file1 file2 @dots{} -The search will be restricted to these source files. If none are given, then -the search will be done for every library file in the search path. -These file must appear only after the pattern or sourcefile. +Index is a language name. Indicates if invoking the compiler for a language +produces an object file. Only authorized case-insensitive values are "false" +and "true" (the default). -These file names are considered to be regular expressions, so for instance -specifying @file{source*.adb} is the same as giving every file in the current -directory whose name starts with @file{source} and whose extension is -@file{adb}. +@item +@strong{Objects_Linked}: single, indexed, case-insensitive index -The location of the spec of the entity will always be displayed, even if it -isn't in one of @file{@var{file1}}, @file{@var{file2}},@enddots{} The -occurrences of the entity in the separate units of the ones given on the -command line will also be displayed. +Index is a language name. Indicates if the object files created by the compiler +for a language need to be linked in the executable. Only authorized +case-insensitive values are "false" and "true" (the default). -Note that if you specify at least one file in this part, @code{gnatfind} may -sometimes not be able to find the body of the subprograms. +@item +@strong{Target}: single -@end table +Value is the name of the target platform. Taken into account only in the main +project. -@noindent -At least one of 'sourcefile' or 'pattern' has to be present on -the command line. +@item +@strong{Runtime}: single, indexed, case-insensitive index -The following switches are available: -@table @option -@c !sort! +Index is a language name. Indicates the runtime directory that is to be used +when using the compiler of the language. Taken into account only in the main +project. +@end itemize -@cindex @option{--version} @command{gnatfind} -Display Copyright and version, then exit disregarding all other options. +@item +@strong{Configuration - Libraries} -@item --help -@cindex @option{--help} @command{gnatfind} -If @option{--version} was not used, display usage, then exit disregarding -all other options. -@item -a -@cindex @option{-a} (@command{gnatfind}) -If this switch is present, @code{gnatfind} and @code{gnatxref} will parse -the read-only files found in the library search path. Otherwise, these files -will be ignored. This option can be used to protect Gnat sources or your own -libraries from being parsed, thus making @code{gnatfind} and @code{gnatxref} -much faster, and their output much smaller. Read-only here refers to access -or permission status in the file system for the current user. +@itemize * -@item -aIDIR -@cindex @option{-aIDIR} (@command{gnatfind}) -When looking for source files also look in directory DIR. The order in which -source file search is undertaken is the same as for @command{gnatmake}. +@item +@strong{Library_Builder}: single -@item -aODIR -@cindex @option{-aODIR} (@command{gnatfind}) -When searching for library and object files, look in directory -DIR. The order in which library files are searched is the same as for -@command{gnatmake}. +Value is the path name of the application that is to be used to build +libraries. Usually the path name of "gprlib". -@item -nostdinc -@cindex @option{-nostdinc} (@command{gnatfind}) -Do not look for sources in the system default directory. +@item +@strong{Library_Support}: single -@item -nostdlib -@cindex @option{-nostdlib} (@command{gnatfind}) -Do not look for library files in the system default directory. +Indicates the level of support of libraries. Only authorized case-insensitive +values are "static_only", "full" or "none" (the default). +@end itemize -@item --ext=@var{extension} -@cindex @option{--ext} (@command{gnatfind}) -Specify an alternate ali file extension. The default is @code{ali} and other -extensions (e.g. @code{gli} for C/C++ sources when using @option{-fdump-xref}) -may be specified via this switch. Note that if this switch overrides the -default, which means that only the new extension will be considered. +@item +@strong{Configuration - Archives} -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gnatfind}) -Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). -@item -d -@cindex @option{-d} (@code{gnatfind}) -If this switch is set, then @code{gnatfind} will output the parent type -reference for each matching derived types. +@itemize * -@item -e -@cindex @option{-e} (@command{gnatfind}) -By default, @code{gnatfind} accept the simple regular expression set for -@samp{pattern}. If this switch is set, then the pattern will be -considered as full Unix-style regular expression. +@item +@strong{Archive_Builder}: list -@item -f -@cindex @option{-f} (@command{gnatfind}) -If this switch is set, the output file names will be preceded by their -directory (if the file was found in the search path). If this switch is -not set, the directory will not be printed. +Value is the name of the application to be used to create a static library +(archive), followed by the options to be used. -@item -g -@cindex @option{-g} (@command{gnatfind}) -If this switch is set, information is output only for library-level -entities, ignoring local entities. The use of this switch may accelerate -@code{gnatfind} and @code{gnatxref}. +@item +@strong{Archive_Builder_Append_Option}: list -@item -IDIR -@cindex @option{-IDIR} (@command{gnatfind}) -Equivalent to @samp{-aODIR -aIDIR}. +Value is the list of options to be used when invoking the archive builder +to add project files into an archive. -@item -pFILE -@cindex @option{-pFILE} (@command{gnatfind}) -Specify a project file (@pxref{GNAT Project Manager}) to use. -By default, @code{gnatxref} and @code{gnatfind} will try to locate a -project file in the current directory. +@item +@strong{Archive_Indexer}: list -If a project file is either specified or found by the tools, then the content -of the source directory and object directory lines are added as if they -had been specified respectively by @samp{-aI} and -@samp{-aO}. +Value is the name of the archive indexer, followed by the required options. -@item -r -@cindex @option{-r} (@command{gnatfind}) -By default, @code{gnatfind} will output only the information about the -declaration, body or type completion of the entities. If this switch is -set, the @code{gnatfind} will locate every reference to the entities in -the files specified on the command line (or in every file in the search -path if no file is given on the command line). +@item +@strong{Archive_Suffix}: single -@item -s -@cindex @option{-s} (@command{gnatfind}) -If this switch is set, then @code{gnatfind} will output the content -of the Ada source file lines were the entity was found. +Value is the extension of archives. When not declared, the extension is ".a". -@item -t -@cindex @option{-t} (@command{gnatfind}) -If this switch is set, then @code{gnatfind} will output the type hierarchy for -the specified type. It act like -d option but recursively from parent -type to parent type. When this switch is set it is not possible to -specify more than one file. +@item +@strong{Library_Partial_Linker}: list -@end table +Value is the name of the partial linker executable, followed by the required +options. +@end itemize -@noindent -All these switches may be in any order on the command line, and may even -appear after the file names. They need not be separated by spaces, thus -you can say @samp{gnatxref -ag} instead of -@samp{gnatxref -a -g}. +@item +@strong{Configuration - Shared Libraries} -As stated previously, gnatfind will search in every directory in the -search path. You can force it to look only in the current directory if -you specify @code{*} at the end of the command line. -@node Project Files for gnatxref and gnatfind -@section Project Files for @command{gnatxref} and @command{gnatfind} +@itemize * -@noindent -Project files allow a programmer to specify how to compile its -application, where to find sources, etc. These files are used -primarily by GPS, but they can also be used -by the two tools -@code{gnatxref} and @code{gnatfind}. +@item +@strong{Shared_Library_Prefix}: single -A project file name must end with @file{.gpr}. If a single one is -present in the current directory, then @code{gnatxref} and @code{gnatfind} will -extract the information from it. If multiple project files are found, none of -them is read, and you have to use the @samp{-p} switch to specify the one -you want to use. +Value is the prefix in the name of shared library files. When not declared, +the prefix is "lib". -The following lines can be included, even though most of them have default -values which can be used in most cases. -The lines can be entered in any order in the file. -Except for @file{src_dir} and @file{obj_dir}, you can only have one instance of -each line. If you have multiple instances, only the last one is taken into -account. +@item +@strong{Shared_Library_Suffix}: single -@table @code -@item src_dir=DIR -[default: @code{"./"}] -specifies a directory where to look for source files. Multiple @code{src_dir} -lines can be specified and they will be searched in the order they -are specified. +Value is the the extension of the name of shared library files. When not +declared, the extension is ".so". -@item obj_dir=DIR -[default: @code{"./"}] -specifies a directory where to look for object and library files. Multiple -@code{obj_dir} lines can be specified, and they will be searched in the order -they are specified +@item +@strong{Symbolic_Link_Supported}: single -@item comp_opt=SWITCHES -[default: @code{""}] -creates a variable which can be referred to subsequently by using -the @code{$@{comp_opt@}} notation. This is intended to store the default -switches given to @command{gnatmake} and @command{gcc}. +Indicates if symbolic links are supported on the platform. Only authorized +case-insensitive values are "true" and "false" (the default). -@item bind_opt=SWITCHES -[default: @code{""}] -creates a variable which can be referred to subsequently by using -the @samp{$@{bind_opt@}} notation. This is intended to store the default -switches given to @command{gnatbind}. +@item +@strong{Library_Major_Minor_Id_Supported}: single -@item link_opt=SWITCHES -[default: @code{""}] -creates a variable which can be referred to subsequently by using -the @samp{$@{link_opt@}} notation. This is intended to store the default -switches given to @command{gnatlink}. +Indicates if major and minor ids for shared library names are supported on +the platform. Only authorized case-insensitive values are "true" and "false" +(the default). -@item main=EXECUTABLE -[default: @code{""}] -specifies the name of the executable for the application. This variable can -be referred to in the following lines by using the @samp{$@{main@}} notation. +@item +@strong{Library_Auto_Init_Supported}: single -@item comp_cmd=COMMAND -[default: @code{"gcc -c -I$@{src_dir@} -g -gnatq"}] -specifies the command used to compile a single file in the application. +Indicates if auto-initialization of Stand-Alone Libraries is supported. Only +authorized case-insensitive values are "true" and "false" (the default). -@item make_cmd=COMMAND -[default: @code{"gnatmake $@{main@} -aI$@{src_dir@} --aO$@{obj_dir@} -g -gnatq -cargs $@{comp_opt@} --bargs $@{bind_opt@} -largs $@{link_opt@}"}] -specifies the command used to recompile the whole application. +@item +@strong{Shared_Library_Minimum_Switches}: list -@item run_cmd=COMMAND -[default: @code{"$@{main@}"}] -specifies the command used to run the application. +Value is the list of required switches when linking a shared library. -@item debug_cmd=COMMAND -[default: @code{"gdb $@{main@}"}] -specifies the command used to debug the application +@item +@strong{Library_Version_Switches}: list -@end table +Value is the list of switches to specify a internal name for a shared library. -@noindent -@command{gnatxref} and @command{gnatfind} only take into account the -@code{src_dir} and @code{obj_dir} lines, and ignore the others. +@item +@strong{Library_Install_Name_Option}: single -@node Regular Expressions in gnatfind and gnatxref -@section Regular Expressions in @code{gnatfind} and @code{gnatxref} +Value is the name of the option that needs to be used, concatenated with the +path name of the library file, when linking a shared library. -@noindent -As specified in the section about @command{gnatfind}, the pattern can be a -regular expression. Actually, there are to set of regular expressions -which are recognized by the program: +@item +@strong{Runtime_Library_Dir}: single, indexed, case-insensitive index -@table @code -@item globbing patterns -These are the most usual regular expression. They are the same that you -generally used in a Unix shell command line, or in a DOS session. +Index is a language name. Value is the path name of the directory where the +runtime libraries are located. -Here is a more formal grammar: -@smallexample -@group -@iftex -@leftskip=.5cm -@end iftex -regexp ::= term -term ::= elmt -- matches elmt -term ::= elmt elmt -- concatenation (elmt then elmt) -term ::= * -- any string of 0 or more characters -term ::= ? -- matches any character -term ::= [char @{char@}] -- matches any character listed -term ::= [char - char] -- matches any character in range -@end group -@end smallexample +@item +@strong{Runtime_Source_Dir}: single, indexed, case-insensitive index -@item full regular expression -The second set of regular expressions is much more powerful. This is the -type of regular expressions recognized by utilities such a @file{grep}. +Index is a language name. Value is the path name of the directory where the +sources of runtime libraries are located. +@end itemize +@end itemize -The following is the form of a regular expression, expressed in Ada -reference manual style BNF is as follows +@node Package Binder Attributes,Package Builder Attributes,Project Level Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager package-binder-attributes}@anchor{1a6}@anchor{gnat_ugn/gnat_project_manager id49}@anchor{1a7} +@subsubsection Package Binder Attributes -@smallexample -@iftex -@leftskip=.5cm -@end iftex -@group -regexp ::= term @{| term@} -- alternation (term or term @dots{}) -term ::= item @{item@} -- concatenation (item then item) -item ::= elmt -- match elmt -item ::= elmt * -- zero or more elmt's -item ::= elmt + -- one or more elmt's -item ::= elmt ? -- matches elmt or nothing -@end group -@group -elmt ::= nschar -- matches given character -elmt ::= [nschar @{nschar@}] -- matches any character listed -elmt ::= [^ nschar @{nschar@}] -- matches any character not listed -elmt ::= [char - char] -- matches chars in given range -elmt ::= \ char -- matches given character -elmt ::= . -- matches any single character -elmt ::= ( regexp ) -- parens used for grouping +@itemize * -char ::= any character, including special characters -nschar ::= any character except ()[].*+?^ -@end group -@end smallexample +@item +@strong{General} -Following are a few examples: -@table @samp -@item abcde|fghi -will match any of the two strings @samp{abcde} and @samp{fghi}, +@itemize * -@item abc*d -will match any string like @samp{abd}, @samp{abcd}, @samp{abccd}, -@samp{abcccd}, and so on, +@item +@strong{Default_Switches}: list, indexed, case-insensitive index -@item [a-z]+ -will match any string which has only lowercase characters in it (and at -least one character. +Index is a language name. Value is the list of switches to be used when binding +code of the language, if there is no applicable attribute Switches. -@end table -@end table +@item +@strong{Switches}: list, optional index, indexed, +case-insensitive index, others allowed -@node Examples of gnatxref Usage -@section Examples of @code{gnatxref} Usage +Index is either a language name or a source file name. Value is the list of +switches to be used when binding code. Index is either the source file name +of the executable to be bound or the language name of the code to be bound. +@end itemize -@subsection General Usage +@item +@strong{Configuration - Binding} -@noindent -For the following examples, we will consider the following units: -@smallexample @c ada -@group -@cartouche -main.ads: -1: @b{with} Bar; -2: @b{package} Main @b{is} -3: @b{procedure} Foo (B : @b{in} Integer); -4: C : Integer; -5: @b{private} -6: D : Integer; -7: @b{end} Main; +@itemize * -main.adb: -1: @b{package} @b{body} Main @b{is} -2: @b{procedure} Foo (B : @b{in} Integer) @b{is} -3: @b{begin} -4: C := B; -5: D := B; -6: Bar.Print (B); -7: Bar.Print (C); -8: @b{end} Foo; -9: @b{end} Main; +@item +@strong{Driver}: single, indexed, case-insensitive index -bar.ads: -1: @b{package} Bar @b{is} -2: @b{procedure} Print (B : Integer); -3: @b{end} bar; -@end cartouche -@end group -@end smallexample +Index is a language name. Value is the name of the application to be used when +binding code of the language. -@table @code +@item +@strong{Required_Switches}: list, indexed, case-insensitive index -@noindent -The first thing to do is to recompile your application (for instance, in -that case just by doing a @samp{gnatmake main}, so that GNAT generates -the cross-referencing information. -You can then issue any of the following commands: +Index is a language name. Value is the list of the required switches to be +used when binding code of the language. -@item gnatxref main.adb -@code{gnatxref} generates cross-reference information for main.adb -and every unit 'with'ed by main.adb. +@item +@strong{Prefix}: single, indexed, case-insensitive index -The output would be: -@smallexample -@iftex -@leftskip=0cm -@end iftex -B Type: Integer - Decl: bar.ads 2:22 -B Type: Integer - Decl: main.ads 3:20 - Body: main.adb 2:20 - Ref: main.adb 4:13 5:13 6:19 -Bar Type: Unit - Decl: bar.ads 1:9 - Ref: main.adb 6:8 7:8 - main.ads 1:6 -C Type: Integer - Decl: main.ads 4:5 - Modi: main.adb 4:8 - Ref: main.adb 7:19 -D Type: Integer - Decl: main.ads 6:5 - Modi: main.adb 5:8 -Foo Type: Unit - Decl: main.ads 3:15 - Body: main.adb 2:15 -Main Type: Unit - Decl: main.ads 2:9 - Body: main.adb 1:14 -Print Type: Unit - Decl: bar.ads 2:15 - Ref: main.adb 6:12 7:12 -@end smallexample +Index is a language name. Value is a prefix to be used for the binder exchange +file name for the language. Used to have different binder exchange file names +when binding different languages. -@noindent -that is the entity @code{Main} is declared in main.ads, line 2, column 9, -its body is in main.adb, line 1, column 14 and is not referenced any where. +@item +@strong{Objects_Path}: single,indexed, case-insensitive index -The entity @code{Print} is declared in bar.ads, line 2, column 15 and it -is referenced in main.adb, line 6 column 12 and line 7 column 12. +Index is a language name. Value is the name of the environment variable that +contains the path for the object directories. -@item gnatxref package1.adb package2.ads -@code{gnatxref} will generates cross-reference information for -package1.adb, package2.ads and any other package 'with'ed by any -of these. +@item +@strong{Object_Path_File}: single,indexed, case-insensitive index -@end table +Index is a language name. Value is the name of the environment variable. The +value of the environment variable is the path name of a text file that +contains the list of object directories. +@end itemize +@end itemize -@subsection Using gnatxref with vi +@node Package Builder Attributes,Package Clean Attributes,Package Binder Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager package-builder-attributes}@anchor{1a8}@anchor{gnat_ugn/gnat_project_manager id50}@anchor{1a9} +@subsubsection Package Builder Attributes -@code{gnatxref} can generate a tags file output, which can be used -directly from @command{vi}. Note that the standard version of @command{vi} -will not work properly with overloaded symbols. Consider using another -free implementation of @command{vi}, such as @command{vim}. -@smallexample -$ gnatxref -v gnatfind.adb > tags -@end smallexample -@noindent -will generate the tags file for @code{gnatfind} itself (if the sources -are in the search path!). +@itemize * -From @command{vi}, you can then use the command @samp{:tag @var{entity}} -(replacing @var{entity} by whatever you are looking for), and vi will -display a new file with the corresponding declaration of entity. +@item +@strong{Default_Switches}: list, indexed, case-insensitive index -@node Examples of gnatfind Usage -@section Examples of @code{gnatfind} Usage +Index is a language name. Value is the list of builder switches to be used when +building an executable of the language, if there is no applicable attribute +Switches. -@table @code +@item +@strong{Switches}: list, optional index, indexed, case-insensitive index, +others allowed -@item gnatfind -f xyz:main.adb -Find declarations for all entities xyz referenced at least once in -main.adb. The references are search in every library file in the search -path. +Index is either a language name or a source file name. Value is the list of +builder switches to be used when building an executable. Index is either the +source file name of the executable to be built or its language name. -The directories will be printed as well (as the @samp{-f} -switch is set) +@item +@strong{Global_Compilation_Switches}: list, optional index, indexed, +case-insensitive index -The output will look like: -@smallexample -directory/main.ads:106:14: xyz <= declaration -directory/main.adb:24:10: xyz <= body -directory/foo.ads:45:23: xyz <= declaration -@end smallexample +Index is either a language name or a source file name. Value is the list of +compilation switches to be used when building an executable. Index is either +the source file name of the executable to be built or its language name. -@noindent -that is to say, one of the entities xyz found in main.adb is declared at -line 12 of main.ads (and its body is in main.adb), and another one is -declared at line 45 of foo.ads +@item +@strong{Executable}: single, indexed, case-insensitive index -@item gnatfind -fs xyz:main.adb -This is the same command as the previous one, instead @code{gnatfind} will -display the content of the Ada source file lines. +Index is an executable source file name. Value is the simple file name of the +executable to be built. -The output will look like: +@item +@strong{Executable_Suffix}: single -@smallexample -directory/main.ads:106:14: xyz <= declaration - procedure xyz; -directory/main.adb:24:10: xyz <= body - procedure xyz is -directory/foo.ads:45:23: xyz <= declaration - xyz : Integer; -@end smallexample +Value is the extension of the file names of executable. When not specified, +the extension is the default extension of executables on the platform. -@noindent -This can make it easier to find exactly the location your are looking -for. +@item +@strong{Global_Configuration_Pragmas}: single -@item gnatfind -r "*x*":main.ads:123 foo.adb -Find references to all entities containing an x that are -referenced on line 123 of main.ads. -The references will be searched only in main.ads and foo.adb. +Value is the file name of a configuration pragmas file that is specified to +the Ada compiler when compiling any Ada source in the project tree. -@item gnatfind main.ads:123 -Find declarations and bodies for all entities that are referenced on -line 123 of main.ads. +@item +@strong{Global_Config_File}: single, indexed, case-insensitive index -This is the same as @code{gnatfind "*":main.adb:123}. +Index is a language name. Value is the file name of a configuration file that +is specified to the compiler when compiling any source of the language in the +project tree. +@end itemize -@item gnatfind mydir/main.adb:123:45 -Find the declaration for the entity referenced at column 45 in -line 123 of file main.adb in directory mydir. Note that it -is usual to omit the identifier name when the column is given, -since the column position identifies a unique reference. -The column has to be the beginning of the identifier, and should not -point to any character in the middle of the identifier. +@node Package Clean Attributes,Package Compiler Attributes,Package Builder Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager package-clean-attributes}@anchor{1aa}@anchor{gnat_ugn/gnat_project_manager id52}@anchor{1ab} +@subsubsection Package Clean Attributes -@end table -@ifclear FSFEDITION -@c ********************************* -@node The GNAT Pretty-Printer gnatpp -@chapter The GNAT Pretty-Printer @command{gnatpp} -@findex gnatpp -@cindex Pretty-Printer -@menu -* Switches for gnatpp:: -* Formatting Rules:: -@end menu +@itemize * -@noindent -The @command{gnatpp} tool is an ASIS-based utility -for source reformatting / pretty-printing. -It takes an Ada source file as input and generates a reformatted -version as output. -You can specify various style directives via switches; e.g., -identifier case conventions, rules of indentation, and comment layout. - -Note: A newly-redesigned set of formatting algorithms used by gnatpp -is now available. -To invoke the old formatting algorithms, use the @option{--pp-old} switch. -Support for @option{--pp-old} will be removed in some future version. - -To produce a reformatted file, @command{gnatpp} invokes the Ada -compiler and generates and uses the ASIS tree for the input source; -thus the input must be legal Ada code, and the tool should have all the -information needed to compile the input source. To provide this information, -you may specify as a tool parameter the project file the input source belongs to -(or you may call @command{gnatpp} -through the @command{gnat} driver (see @ref{The GNAT Driver and -Project Files}). Another possibility is to specify the source search -path and needed configuration files in @option{-cargs} section of @command{gnatpp} -call, see the description of the @command{gnatpp} switches below. - -@command{gnatpp} cannot process sources that contain -preprocessing directives. - -The @command{gnatpp} command has the form - -@smallexample -@c $ gnatpp @ovar{switches} @var{filename} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatpp @r{[}@var{switches}@r{]} @var{filename} @r{[}-cargs @var{gcc_switches}@r{]} -@end smallexample - -@noindent -where -@itemize @bullet -@item -@var{switches} is an optional sequence of switches defining such properties as -the formatting rules, the source search path, and the destination for the -output source file +@item +@strong{Switches}: list -@item -@var{filename} is the name (including the extension) of the source file to -reformat; wildcards or several file names on the same gnatpp command are -allowed. The file name may contain path information; it does not have to -follow the GNAT file naming rules +Value is a list of switches to be used by the cleaning application. -@item -@samp{@var{gcc_switches}} is a list of switches for -@command{gcc}. They will be passed on to all compiler invocations made by -@command{gnatpp} to generate the ASIS trees. Here you can provide -@option{-I} switches to form the source search path, -use the @option{-gnatec} switch to set the configuration file, etc. +@item +@strong{Source_Artifact_Extensions}: list, indexed, case-insensitive index + +Index is a language names. Value is the list of extensions for file names +derived from object file names that need to be cleaned in the object +directory of the project. + +@item +@strong{Object_Artifact_Extensions}: list, indexed, case-insensitive index + +Index is a language names. Value is the list of extensions for file names +derived from source file names that need to be cleaned in the object +directory of the project. + +@item +@strong{Artifacts_In_Object_Dir}: single + +Value is a list of file names expressed as regular expressions that are to be +deleted by gprclean in the object directory of the project. + +@item +@strong{Artifacts_In_Exec_Dir}: single + +Value is list of file names expressed as regular expressions that are to be +deleted by gprclean in the exec directory of the main project. @end itemize -@node Switches for gnatpp -@section Switches for @command{gnatpp} +@node Package Compiler Attributes,Package Cross_Reference Attributes,Package Clean Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager id53}@anchor{1ac}@anchor{gnat_ugn/gnat_project_manager package-compiler-attributes}@anchor{1ad} +@subsubsection Package Compiler Attributes -@noindent -The following subsections describe the various switches accepted by -@command{gnatpp}, organized by category. -You specify a switch by supplying a name and generally also a value. -In many cases the values for a switch with a given name are incompatible with -each other -(for example the switch that controls the casing of a reserved word may have -exactly one value: upper case, lower case, or -mixed case) and thus exactly one such switch can be in effect for an -invocation of @command{gnatpp}. -If more than one is supplied, the last one is used. -However, some values for the same switch are mutually compatible. -You may supply several such switches to @command{gnatpp}, but then -each must be specified in full, with both the name and the value. -Abbreviated forms (the name appearing once, followed by each value) are -not permitted. +@itemize * -@menu -* Alignment Control:: -* Casing Control:: -* General Text Layout Control:: -* Other Formatting Options:: -* Setting the Source Search Path:: -* Output File Control:: -* Other gnatpp Switches:: -@end menu +@item +@strong{General} -@node Alignment Control -@subsection Alignment Control -@cindex Alignment control in @command{gnatpp} -@noindent -Programs can be easier to read if certain constructs are vertically aligned. -By default alignment of the following constructs is set ON: -@code{:} in declarations, @code{:=} in initializations in declarations -@code{:=} in assignment statements, @code{=>} in associations, and -@code{at} keywords in the component clauses in record -representation clauses. +@itemize * -@table @option -@cindex @option{-A@var{n}} (@command{gnatpp}) +@item +@strong{Default_Switches}: list, indexed, case-insensitive index -@item -A0 -Set alignment to OFF +Index is a language name. Value is a list of switches to be used when invoking +the compiler for the language for a source of the project, if there is no +applicable attribute Switches. -@item -A1 -Set alignment to ON -@end table +@item +@strong{Switches}: list, optional index, indexed, case-insensitive index, +others allowed -@node Casing Control -@subsection Casing Control -@cindex Casing control in @command{gnatpp} +Index is a source file name or a language name. Value is the list of switches +to be used when invoking the compiler for the source or for its language. -@noindent -@command{gnatpp} allows you to specify the casing for reserved words, -pragma names, attribute designators and identifiers. -For identifiers you may define a -general rule for name casing but also override this rule -via a set of dictionary files. +@item +@strong{Local_Configuration_Pragmas}: single -Three types of casing are supported: lower case, upper case, and mixed case. -``Mixed case'' means that the first letter, and also each letter immediately -following an underscore, are converted to their uppercase forms; -all the other letters are converted to their lowercase forms. +Value is the file name of a configuration pragmas file that is specified to +the Ada compiler when compiling any Ada source in the project. -@table @option -@cindex @option{-a@var{x}} (@command{gnatpp}) -@item -aL -Attribute designators are lower case - -@item -aU -Attribute designators are upper case - -@item -aM -Attribute designators are mixed case (this is the default) - -@cindex @option{-k@var{x}} (@command{gnatpp}) -@item -kL -Keywords (technically, these are known in Ada as @emph{reserved words}) are -lower case (this is the default) - -@item -kU -Keywords are upper case - -@cindex @option{-n@var{x}} (@command{gnatpp}) -@item -nD -Name casing for defining occurrences are as they appear in the source file -(this is the default) - -@item -nU -Names are in upper case - -@item -nL -Names are in lower case - -@item -nM -Names are in mixed case - -@cindex @option{-ne@var{x}} (@command{gnatpp}) -@item -neD -Enumeration literal casing for defining occurrences are as they appear in the -source file. Overrides -n casing setting. - -@item -neU -Enumeration literals are in upper case. Overrides -n casing -setting. - -@item -neL -Enumeration literals are in lower case. Overrides -n casing -setting. - -@item -neM -Enumeration literals are in mixed case. Overrides -n casing -setting. - -@cindex @option{-nt@var{x}} (@command{gnatpp}) -@item -neD -Names introduced by type and subtype declarations are always -cased as they appear in the declaration in the source file. -Overrides -n casing setting. - -@item -ntU -Names introduced by type and subtype declarations are always in -upper case. Overrides -n casing setting. - -@item -ntL -Names introduced by type and subtype declarations are always in -lower case. Overrides -n casing setting. - -@item -ntM -Names introduced by type and subtype declarations are always in -mixed case. Overrides -n casing setting. - -@item -nnU -Names introduced by number declarations are always in -upper case. Overrides -n casing setting. - -@item -nnL -Names introduced by number declarations are always in -lower case. Overrides -n casing setting. - -@item -nnM -Names introduced by number declarations are always in -mixed case. Overrides -n casing setting. - -@cindex @option{-p@var{x}} (@command{gnatpp}) -@item -pL -Pragma names are lower case - -@item -pU -Pragma names are upper case - -@item -pM -Pragma names are mixed case (this is the default) - -@item -D@var{file} -@cindex @option{-D} (@command{gnatpp}) -Use @var{file} as a @emph{dictionary file} that defines -the casing for a set of specified names, -thereby overriding the effect on these names by -any explicit or implicit --n switch. -To supply more than one dictionary file, -use several @option{-D} switches. - -@noindent -@option{gnatpp} implicitly uses a @emph{default dictionary file} -to define the casing for the Ada predefined names and -the names declared in the GNAT libraries. - -@item -D- -@cindex @option{-D-} (@command{gnatpp}) -Do not use the default dictionary file; -instead, use the casing -defined by a @option{-n} switch and any explicit -dictionary file(s) -@end table - -@noindent -The structure of a dictionary file, and details on the conventions -used in the default dictionary file, are defined in @ref{Name Casing}. - -The @option{-D-} and -@option{-D@var{file}} switches are mutually -compatible. - -@noindent -This group of @command{gnatpp} switches controls the layout of comments and -complex syntactic constructs. See @ref{Formatting Comments} for details -on their effect. - -@table @option -@cindex @option{-c@var{n}} (@command{gnatpp}) -@item -c0 -All comments remain unchanged. - -@item -c1 -GNAT-style comment line indentation. -This is the default. - -@item -c3 -GNAT-style comment beginning. - -@item -c4 -Fill comment blocks. - -@item -c5 -Keep unchanged special form comments. -This is the default. - -@item --comments-only -@cindex @option{--comments-only} @command{gnatpp} -Format just the comments. - -@cindex @option{--no-separate-is} (@command{gnatpp}) -@item --no-separate-is -Do not place the keyword @code{is} on a separate line in a subprogram body in -case if the spec occupies more than one line. - -@cindex @option{--separate-loop-then} (@command{gnatpp}) -@item --separate-loop-then -Place the keyword @code{loop} in FOR and WHILE loop statements and the -keyword @code{then} in IF statements on a separate line. - -@cindex @option{--no-separate-loop-then} (@command{gnatpp}) -@item --no-separate-loop-then -Do not place the keyword @code{loop} in FOR and WHILE loop statements and the -keyword @code{then} in IF statements on a separate line. This option is -incompatible with @option{--separate-loop-then} option. - -@cindex @option{--use-on-new-line} (@command{gnatpp}) -@item --use-on-new-line -Start each USE clause in a context clause from a separate line. - -@cindex @option{--insert-blank-lines} (@command{gnatpp}) -@item --insert-blank-lines -Insert blank lines where appropriate (between bodies and other large -constructs). - -@cindex @option{--preserve-blank-lines} (@command{gnatpp}) -@item --preserve-blank-lines -Preserve blank lines in the input. By default, gnatpp will squeeze -multiple blank lines down to one. - -@end table - -@noindent -The @option{-c} switches are compatible with one another, except that -the @option{-c0} switch disables all other comment formatting -switches. +@item +@strong{Local_Config_File}: single, indexed, case-insensitive index + +Index is a language name. Value is the file name of a configuration file that +is specified to the compiler when compiling any source of the language in the +project. +@end itemize + +@item +@strong{Configuration - Compiling} + + +@itemize * + +@item +@strong{Driver}: single, indexed, case-insensitive index + +Index is a language name. Value is the name of the executable for the compiler +of the language. + +@item +@strong{Language_Kind}: single, indexed, case-insensitive index + +Index is a language name. Indicates the kind of the language, either file based +or unit based. Only authorized case-insensitive values are "unit_based" and +"file_based" (the default). + +@item +@strong{Dependency_Kind}: single, indexed, case-insensitive index + +Index is a language name. Indicates how the dependencies are handled for the +language. Only authorized case-insensitive values are "makefile", "ali_file", +"ali_closure" or "none" (the default). + +@item +@strong{Required_Switches}: list, indexed, case-insensitive index + +Equivalent to attribute Leading_Required_Switches. + +@item +@strong{Leading_Required_Switches}: list, indexed, case-insensitive index + +Index is a language name. Value is the list of the minimum switches to be used +at the beginning of the command line when invoking the compiler for the +language. + +@item +@strong{Trailing_Required_Switches}: list, indexed, case-insensitive index + +Index is a language name. Value is the list of the minimum switches to be used +at the end of the command line when invoking the compiler for the language. + +@item +@strong{PIC_Option}: list, indexed, case-insensitive index + +Index is a language name. Value is the list of switches to be used when +compiling a source of the language when the project is a shared library +project. + +@item +@strong{Path_Syntax}: single, indexed, case-insensitive index + +Index is a language name. Value is the kind of path syntax to be used when +invoking the compiler for the language. Only authorized case-insensitive +values are "canonical" and "host" (the default). +@item +@strong{Source_File_Switches}: single, indexed, case-insensitive index -@node General Text Layout Control -@subsection General Text Layout Control +Index is a language name. Value is a list of switches to be used just before +the path name of the source to compile when invoking the compiler for a source +of the language. -@noindent -These switches allow control over line length and indentation. +@item +@strong{Object_File_Suffix}: single, indexed, case-insensitive index -@table @option -@item -M@var{nnn} -@cindex @option{-M} (@command{gnatpp}) -Maximum line length, @var{nnn} from 32@dots{}256, the default value is 79 - -@item -i@var{nnn} -@cindex @option{-i} (@command{gnatpp}) -Indentation level, @var{nnn} from 1@dots{}9, the default value is 3 - -@item -cl@var{nnn} -@cindex @option{-cl} (@command{gnatpp}) -Indentation level for continuation lines (relative to the line being -continued), @var{nnn} from 1@dots{}9. -The default -value is one less than the (normal) indentation level, unless the -indentation is set to 1 (in which case the default value for continuation -line indentation is also 1) -@end table - -@node Other Formatting Options -@subsection Other Formatting Options - -@noindent -These switches control other formatting not listed above. - -@table @option -@item --decimal-grouping=@var{n} -@cindex @option{--decimal-grouping} @command{gnatpp} -Put underscores in decimal literals (numeric literals without a base) -every @var{n} characters. If a literal already has one or more -underscores, it is not modified. For example, with -@code{--decimal-grouping=3}, @code{1000000} will be changed to -@code{1_000_000}. - -@item --based-grouping=@var{n} -@cindex @option{--based-grouping} @command{gnatpp} -Same as @code{--decimal-grouping}, but for based literals. For -example, with @code{--based-grouping=4}, @code{16#0001FFFE#} will be -changed to @code{16#0001_FFFE#}. - -@item --split-line-before-op -@cindex @option{--split-line-before-op} (@command{gnatpp}) -If it is necessary to split a line at a binary operator, by default -the line is split after the operator. With this option, it is split -before the operator. - -@item --RM-style-spacing -@cindex @option{--RM-style-spacing} (@command{gnatpp}) -Do not insert an extra blank before various occurrences of -`(' and `:'. This also turns off alignment. - -@item -ff -@cindex @option{-ff} (@command{gnatpp}) -Insert a Form Feed character after a pragma Page. - -@item --call_threshold=@var{nnn} -@cindex @option{--call_threshold} (@command{gnatpp}) -If the number of parameter associations is greater than @var{nnn} and if at -least one association uses named notation, start each association from -a new line. If @var{nnn} is 0, no check for the number of associations -is made; this is the default. - -@item --par_threshold=@var{nnn} -@cindex @option{--par_threshold} (@command{gnatpp}) -If the number of parameter specifications is greater than @var{nnn} -(or equal to @var{nnn} in case of a function), start each specification from -a new line. This feature is disabled by default. -@end table - -@node Setting the Source Search Path -@subsection Setting the Source Search Path - -@noindent -To define the search path for the input source file, @command{gnatpp} -uses the same switches as the GNAT compiler, with the same effects: - -@table @option -@item -I@var{dir} -@cindex @option{-I} (@command{gnatpp}) - -@item -I- -@cindex @option{-I-} (@command{gnatpp}) - -@item -gnatec=@var{path} -@cindex @option{-gnatec} (@command{gnatpp}) - -@end table - -@node Output File Control -@subsection Output File Control - -@noindent -By default the output is sent to a file whose name is obtained by appending -the @file{.pp} suffix to the name of the input file. -If the file with this name already exists, it is overwritten. -Thus if the input file is @file{my_ada_proc.adb} then -@command{gnatpp} will produce @file{my_ada_proc.adb.pp} -as output file. -The output may be redirected by the following switches: - -@table @option -@item --output-dir=@var{dir} -@cindex @option{--output-dir} (@command{gnatpp}) -Generate output file in directory @file{dir} with the same name as the input -file. If @file{dir} is the same as the directory containing the input file, -the input file is not processed; use @option{-rnb} -if you want to update the input file in place. - -@item -pipe -@cindex @option{-pipe} (@command{gnatpp}) -Send the output to @code{Standard_Output} - -@item -o @var{output_file} -@cindex @option{-o} (@code{gnatpp}) -Write the output into @var{output_file}. -If @var{output_file} already exists, @command{gnatpp} terminates without -reading or processing the input file. - -@item -of @var{output_file} -@cindex @option{-of} (@command{gnatpp}) -Write the output into @var{output_file}, overwriting the existing file -(if one is present). - -@item -r -@cindex @option{-r} (@command{gnatpp}) -Replace the input source file with the reformatted output, and copy the -original input source into the file whose name is obtained by appending the -@file{.npp} suffix to the name of the input file. -If a file with this name already exists, @command{gnatpp} terminates without -reading or processing the input file. - -@item -rf -@cindex @option{-rf} (@code{gnatpp}) -Like @option{-r} except that if the file with the specified name -already exists, it is overwritten. - -@item -rnb -@cindex @option{-rnb} (@command{gnatpp}) -Replace the input source file with the reformatted output without -creating any backup copy of the input source. - -@item --eol=@var{xxx} -@cindex @option{--eol} (@code{gnatpp}) -Specifies the line-ending style of the reformatted output file. The @var{xxx} -string specified with the switch may be: -@itemize @bullet -@item ``@option{dos}'' MS DOS style, lines end with CR LF characters -@item ``@option{crlf}'' -the same as @option{dos} -@item ``@option{unix}'' UNIX style, lines end with LF character -@item ``@option{lf}'' -the same as @option{unix} +Index is a language name. Value is the extension of the object files created +by the compiler of the language. When not specified, the extension is the +default one for the platform. + +@item +@strong{Object_File_Switches}: list, indexed, case-insensitive index + +Index is a language name. Value is the list of switches to be used by the +compiler of the language to specify the path name of the object file. When not +specified, the switch used is "-o". + +@item +@strong{Multi_Unit_Switches}: list, indexed, case-insensitive index + +Index is a language name. Value is the list of switches to be used to compile +a unit in a multi unit source of the language. The index of the unit in the +source is concatenated with the last switches in the list. + +@item +@strong{Multi_Unit_Object_Separator}: single, indexed, case-insensitive index + +Index is a language name. Value is the string to be used in the object file +name before the index of the unit, when compiling a unit in a multi unit source +of the language. @end itemize -@item -W@var{e} -@cindex @option{-W} (@command{gnatpp}) -Specify the wide character encoding method for the input and output files. -@var{e} is one of the following: +@item +@strong{Configuration - Mapping Files} -@itemize @bullet -@item h -Hex encoding +@itemize * -@item u -Upper half encoding +@item +@strong{Mapping_File_Switches}: list, indexed, case-insensitive index -@item s -Shift/JIS encoding +Index is a language name. Value is the list of switches to be used to specify +a mapping file when invoking the compiler for a source of the language. -@item e -EUC encoding +@item +@strong{Mapping_Spec_Suffix}: single, indexed, case-insensitive index -@item 8 -UTF-8 encoding +Index is a language name. Value is the suffix to be used in a mapping file +to indicate that the source is a spec. -@item b -Brackets encoding (default value) +@item +@strong{Mapping_Body_Suffix}: single, indexed, case-insensitive index + +Index is a language name. Value is the suffix to be used in a mapping file +to indicate that the source is a body. @end itemize -@end table +@item +@strong{Configuration - Config Files} -@noindent -Options @option{-o} and -@option{-of} are allowed only if the call to gnatpp -contains only one file to reformat. -Option -@option{--eol} -and -@option{-W} -cannot be used together -with @option{-pipe} option. - -@node Other gnatpp Switches -@subsection Other @code{gnatpp} Switches - -@noindent -The additional @command{gnatpp} switches are defined in this subsection. - -@table @option -@item --version -@cindex @option{--version} @command{gnatpp} -Display copyright and version, then exit disregarding all other options. - -@item --help -@cindex @option{--help} @command{gnatpp} -Display usage, then exit disregarding all other options. - -@item -P @var{file} -@cindex @option{-P} @command{gnatpp} -Indicates the name of the project file that describes the set of sources -to be processed. The exact set of argument sources depends on other options -specified; see below. - -@item -U -@cindex @option{-U} @command{gnatpp} -If a project file is specified and no argument source is explicitly -specified (either directly or by means of @option{-files} option), process -all the units of the closure of the argument project. Otherwise this option -has no effect. - -@item -U @var{main_unit} -If a project file is specified and no argument source is explicitly -specified (either directly or by means of @option{-files} option), process -the closure of units rooted at @var{main_unit}. Otherwise this option -has no effect. - -@item -X@var{name}=@var{value} -@cindex @option{-X} @command{gnatpp} -Indicates that external variable @var{name} in the argument project -has the value @var{value}. Has no effect if no project is specified as -tool argument. - -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gnatpp}) -Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). - -@item --incremental -@cindex @option{--incremental} @command{gnatpp} -Incremental processing on a per-file basis. Source files are only -processed if they have been modified, or if files they depend on have -been modified. This is similar to the way gnatmake/gprbuild only -compiles files that need to be recompiled. A project file is required -in this mode, and the gnat driver (as in @command{gnat pretty}) is not -supported. - -@item --pp-off=@var{xxx} -@cindex @option{--pp-off} @command{gnatpp} -Use @code{--xxx} as the command to turn off pretty printing, instead -of the default @code{--!pp off}. - -@item --pp-on=@var{xxx} -@cindex @option{--pp-on} @command{gnatpp} -Use @code{--xxx} as the command to turn pretty printing back on, instead -of the default @code{--!pp on}. - -@item --pp-old -@cindex @option{--pp-old} @command{gnatpp} -Use the old formatting algorithms. - -@item -files @var{filename} -@cindex @option{-files} (@code{gnatpp}) -Take the argument source files from the specified file. This file should be an -ordinary text file containing file names separated by spaces or -line breaks. You can use this switch more than once in the same call to -@command{gnatpp}. You also can combine this switch with an explicit list of -files. -@item -j@var{n} -@cindex @option{-j} (@command{gnatpp}) -Without @option{--incremental}, use @var{n} processes to carry out the -tree creations (internal representations of the argument sources). On -a multiprocessor machine this speeds up processing of big sets of -argument sources. If @var{n} is 0, then the maximum number of parallel -tree creations is the number of core processors on the platform. This -option cannot be used together with @option{-r}, -@option{-rf} or -@option{-rnb} option. +@itemize * -With @option{--incremental}, use @var{n} @command{gnatpp} processes to -perform pretty-printing in parallel. @var{n} = 0 means the same as -above. In this case, @option{-r}, -@option{-rf} or -@option{-rnb} options are allowed. +@item +@strong{Config_File_Switches}: list: single, indexed, case-insensitive index -@cindex @option{-t} (@command{gnatpp}) -@item -t -Print out execution time. +Index is a language name. Value is the list of switches to specify to the +compiler of the language a configuration file. -@item -v -@cindex @option{-v} (@command{gnatpp}) -Verbose mode +@item +@strong{Config_Body_File_Name}: single, indexed, case-insensitive index -@item -q -@cindex @option{-q} (@command{gnatpp}) -Quiet mode -@end table +Index is a language name. Value is the template to be used to indicate a +configuration specific to a body of the language in a configuration +file. -@noindent -If a project file is specified and no argument source is explicitly -specified (either directly or by means of @option{-files} option), and no -@option{-U} is specified, then the set of processed sources is -all the immediate units of the argument project. +@item +@strong{Config_Body_File_Name_Index}: single, indexed, case-insensitive index +Index is a language name. Value is the template to be used to indicate a +configuration specific to the body a unit in a multi unit source of the +language in a configuration file. -@node Formatting Rules -@section Formatting Rules +@item +@strong{Config_Body_File_Name_Pattern}: single, indexed, +case-insensitive index -@noindent -The following subsections show how @command{gnatpp} treats white space, -comments, program layout, and name casing. -They provide detailed descriptions of the switches shown above. +Index is a language name. Value is the template to be used to indicate a +configuration for all bodies of the languages in a configuration file. -@menu -* Disabling Pretty Printing:: -* White Space and Empty Lines:: -* Formatting Comments:: -* Name Casing:: -@end menu +@item +@strong{Config_Spec_File_Name}: single, indexed, case-insensitive index -@node Disabling Pretty Printing -@subsection Disabling Pretty Printing +Index is a language name. Value is the template to be used to indicate a +configuration specific to a spec of the language in a configuration +file. -@noindent -Pretty printing is highly heuristic in nature, and sometimes doesn't -do exactly what you want. If you wish to format a certain region of -code by hand, you can turn off pretty printing in that region by -surrounding it with special comments that start with @code{--!pp off} -and @code{--!pp on}. The text in that region will then be reproduced -verbatim in the output with no formatting. +@item +@strong{Config_Spec_File_Name_Index}: single, indexed, case-insensitive index -To disable pretty printing for the whole file, put @code{--!pp off} at -the top, with no following @code{--!pp on}. +Index is a language name. Value is the template to be used to indicate a +configuration specific to the spec a unit in a multi unit source of the +language in a configuration file. -The comments must appear on a line by themselves, with nothing -preceding except spaces. The initial text of the comment must be -exactly @code{--!pp off} or @code{--!pp on} (case sensitive), but may -be followed by arbitrary additional text. For example: +@item +@strong{Config_Spec_File_Name_Pattern}: single, indexed, +case-insensitive index -@smallexample @c ada -@cartouche -@b{package} Interrupts @b{is} - --@i{!pp off -- turn off pretty printing so "Interrupt_Kind" lines up} - @b{type} Interrupt_Kind @b{is} - (Asynchronous_Interrupt_Kind, - Synchronous_Interrupt_Kind, - Green_Interrupt_Kind); - --@i{!pp on -- reenable pretty printing} +Index is a language name. Value is the template to be used to indicate a +configuration for all specs of the languages in a configuration file. - ... -@end cartouche -@end smallexample - -You can specify different comment strings using the @code{--pp-off} -and @code{--pp-on} switches. For example, if you say @code{gnatpp ---pp-off=' pp-' *.ad?} then gnatpp will recognize comments of the form -@code{-- pp-} instead of @code{--!pp off} for disabling pretty -printing. Note that the leading @code{--} of the comment is not -included in the argument to these switches. - -@node White Space and Empty Lines -@subsection White Space and Empty Lines - -@noindent -@command{gnatpp} does not have an option to control space characters. -It will add or remove spaces according to the style illustrated by the -examples in the @cite{Ada Reference Manual}. -The output file will contain no lines with trailing white space. - -By default, a sequence of one or more blank lines in the input is -converted to a single blank line in the output; multiple blank lines -are squeezed down to one. -The @option{--preserve-blank-lines} option -turns off the squeezing; each blank line in the input is copied -to the output. -The @option{--insert-blank-lines} option -causes additional blank lines to be inserted if not already -present in the input (e.g. between bodies). - -@node Formatting Comments -@subsection Formatting Comments - -@noindent -Comments in Ada code are of two kinds: -@itemize @bullet -@item -a @emph{whole-line comment}, which appears by itself (possibly preceded by -white space) on a line +@item +@strong{Config_File_Unique}: single, indexed, case-insensitive index -@item -an @emph{end-of-line comment}, which follows some other Ada code on -the same line. +Index is a language name. Indicates if there should be only one configuration +file specified to the compiler of the language. Only authorized +case-insensitive values are "true" and "false" (the default). @end itemize -@noindent -A whole-line comment is indented according to the surrounding code, -with some exceptions. -Comments that start in column 1 are kept there. -If possible, comments are not moved so far to the right that the maximum -line length is exceeded. -The @option{-c0} option -turns off comment formatting. -Special-form comments such as SPARK-style @code{--#...} are left alone. - -For an end-of-line comment, @command{gnatpp} tries to leave the same -number of spaces between the end of the preceding Ada code and the -beginning of the comment as appear in the original source. - -@noindent -The @option{-c3} switch -(GNAT style comment beginning) has the following -effect: - -@itemize @bullet -@item -For each whole-line comment that does not end with two hyphens, -@command{gnatpp} inserts spaces if necessary after the starting two hyphens -to ensure that there are at least two spaces between these hyphens and the -first non-blank character of the comment. +@item +@strong{Configuration - Dependencies} + + +@itemize * + +@item +@strong{Dependency_Switches}: list, indexed, case-insensitive index + +Index is a language name. Value is the list of switches to be used to specify +to the compiler the dependency file when the dependency kind of the language is +file based, and when Dependency_Driver is not specified for the language. + +@item +@strong{Dependency_Driver}: list, indexed, case-insensitive index + +Index is a language name. Value is the name of the executable to be used to +create the dependency file for a source of the language, followed by the +required switches. @end itemize -@noindent -The @option{-c4} switch specifies that -whole-line comments that form a paragraph will be filled in typical -word processor style (that is, moving words between lines to make the -lines other than the last similar in length ). - -@noindent -The @option{--comments-only} switch specifies that only the comments -are formatted; the rest of the program text is left alone. The -comments are formatted according to the -c3 and -c4 switches; other -formatting switches are ignored. For example, @option{--comments-only --c4} means to fill comment paragraphs, and do nothing else. Likewise, -@option{--comments-only -c3} ensures comments start with at least two -spaces after @code{--}, and @option{--comments-only -c3 -c4} does -both. If @option{--comments-only} is given without @option{-c3} or -@option{-c4}, then gnatpp doesn't format anything. - -@node Name Casing -@subsection Name Casing - -@noindent -@command{gnatpp} always converts the usage occurrence of a (simple) name to -the same casing as the corresponding defining identifier. - -You control the casing for defining occurrences via the -@option{-n} switch. -With @option{-nD} (``as declared'', which is the default), -defining occurrences appear exactly as in the source file -where they are declared. -The other values for this switch --- -@option{-nU}, -@option{-nL}, -@option{-nM} --- -result in -upper, lower, or mixed case, respectively. -If @command{gnatpp} changes the casing of a defining -occurrence, it analogously changes the casing of all the -usage occurrences of this name. - -If the defining occurrence of a name is not in the source compilation unit -currently being processed by @command{gnatpp}, the casing of each reference to -this name is changed according to the value of the @option{-n} -switch (subject to the dictionary file mechanism described below). -Thus @command{gnatpp} acts as though the @option{-n} switch -had affected the -casing for the defining occurrence of the name. - -The options -@option{-a@var{x}}, -@option{-k@var{x}}, -@option{-ne@var{x}}, -@option{-nt@var{x}}, -@option{-nn@var{x}}, and -@option{-p@var{x}} -allow finer-grained control over casing for -attributes, keywords, enumeration literals, -types, named numbers and pragmas, respectively. -@option{-nt@var{x}} covers subtypes and -task and protected bodies as well. - -Some names may need to be spelled with casing conventions that are not -covered by the upper-, lower-, and mixed-case transformations. -You can arrange correct casing by placing such names in a -@emph{dictionary file}, -and then supplying a @option{-D} switch. -The casing of names from dictionary files overrides -any @option{-n} switch. - -To handle the casing of Ada predefined names and the names from GNAT libraries, -@command{gnatpp} assumes a default dictionary file. -The name of each predefined entity is spelled with the same casing as is used -for the entity in the @cite{Ada Reference Manual} (usually mixed case). -The name of each entity in the GNAT libraries is spelled with the same casing -as is used in the declaration of that entity. - -The @w{@option{-D-}} switch suppresses the use of -the default dictionary file. Instead, the casing for predefined and -GNAT-defined names will be established by the -@option{-n} switch or explicit dictionary files. For -example, by default the names @code{Ada.Text_IO} and -@code{GNAT.OS_Lib} will appear as just shown, even in the presence of -a @option{-nU} switch. To ensure that even -such names are rendered in uppercase, additionally supply the -@w{@option{-D-}} switch (or else place these names -in upper case in a dictionary file). - -A dictionary file is a plain text file; each line in this file can be -either a blank line (containing only space characters), an Ada comment -line, or the specification of exactly one @emph{casing schema}. - -A casing schema is a string that has the following syntax: - -@smallexample -@cartouche - @var{casing_schema} ::= @var{identifier} | *@var{simple_identifier}* +@item +@strong{Configuration - Search Paths} - @var{simple_identifier} ::= @var{letter}@{@var{letter_or_digit}@} -@end cartouche -@end smallexample -@noindent -(See @cite{Ada Reference Manual}, Section 2.3) for the definition of the -@var{identifier} lexical element and the @var{letter_or_digit} category.) +@itemize * -The casing schema string can be followed by white space and/or an Ada-style -comment; any amount of white space is allowed before the string. +@item +@strong{Include_Switches}: list, indexed, case-insensitive index -If a dictionary file is passed as -the value of a @option{-D@var{file}} switch -then for every -simple name and every identifier, @command{gnatpp} checks if the dictionary -defines the casing for the name or for some of its parts (the term ``subword'' -is used below to denote the part of a name which is delimited by ``_'' or by -the beginning or end of the word and which does not contain any ``_'' inside): +Index is a language name. Value is the list of switches to specify to the +compiler of the language to indicate a directory to look for sources. -@itemize @bullet -@item -if the whole name is in the dictionary, @command{gnatpp} uses for this name -the casing defined by the dictionary; no subwords are checked for this word +@item +@strong{Include_Path}: single, indexed, case-insensitive index -@item -for every subword @command{gnatpp} checks if the dictionary contains the -corresponding string of the form @code{*@var{simple_identifier}*}, -and if it does, the casing of this @var{simple_identifier} is used -for this subword +Index is a language name. Value is the name of an environment variable that +contains the path of all the directories that the compiler of the language +may search for sources. -@item -if the whole name does not contain any ``_'' inside, and if for this name -the dictionary contains two entries - one of the form @var{identifier}, -and another - of the form *@var{simple_identifier}*, then the first one -is applied to define the casing of this name +@item +@strong{Include_Path_File}: single, indexed, case-insensitive index -@item -if more than one dictionary file is passed as @command{gnatpp} switches, each -dictionary adds new casing exceptions and overrides all the existing casing -exceptions set by the previous dictionaries +Index is a language name. Value is the name of an environment variable the +value of which is the path name of a text file that contains the directories +that the compiler of the language may search for sources. -@item -when @command{gnatpp} checks if the word or subword is in the dictionary, -this check is not case sensitive +@item +@strong{Object_Path_Switches}: list, indexed, case-insensitive index + +Index is a language name. Value is the list of switches to specify to the +compiler of the language the name of a text file that contains the list of +object directories. When this attribute is not declared, the text file is +not created. +@end itemize @end itemize -@noindent -For example, suppose we have the following source to reformat: +@node Package Cross_Reference Attributes,Package Finder Attributes,Package Compiler Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager id54}@anchor{1ae}@anchor{gnat_ugn/gnat_project_manager package-cross-reference-attributes}@anchor{1af} +@subsubsection Package Cross_Reference Attributes -@smallexample @c ada -@cartouche -@b{procedure} test @b{is} - name1 : integer := 1; - name4_name3_name2 : integer := 2; - name2_name3_name4 : Boolean; - name1_var : Float; -@b{begin} - name2_name3_name4 := name4_name3_name2 > name1; -@b{end}; -@end cartouche -@end smallexample -@noindent -And suppose we have two dictionaries: -@smallexample -@cartouche -@i{dict1:} - NAME1 - *NaMe3* - *Name1* -@end cartouche +@itemize * -@cartouche -@i{dict2:} - *NAME3* -@end cartouche -@end smallexample +@item +@strong{Default_Switches}: list, indexed, case-insensitive index -@noindent -If @command{gnatpp} is called with the following switches: +Index is a language name. Value is a list of switches to be used when invoking +@cite{gnatxref} for a source of the language, if there is no applicable +attribute Switches. -@smallexample -@command{gnatpp -nM -D dict1 -D dict2 test.adb} -@end smallexample +@item +@strong{Switches}: list, optional index, indexed, case-insensitive index, +others allowed -@noindent -then we will get the following name casing in the @command{gnatpp} output: +Index is a source file name. Value is the list of switches to be used when +invoking @cite{gnatxref} for the source. +@end itemize -@smallexample @c ada -@cartouche -@b{procedure} Test @b{is} - NAME1 : Integer := 1; - Name4_NAME3_Name2 : Integer := 2; - Name2_NAME3_Name4 : Boolean; - Name1_Var : Float; -@b{begin} - Name2_NAME3_Name4 := Name4_NAME3_Name2 > NAME1; -@b{end} Test; -@end cartouche -@end smallexample -@end ifclear -@ifclear FSFEDITION -@c ********************************* -@node The Ada-to-XML converter gnat2xml -@chapter The Ada-to-XML converter @command{gnat2xml} -@findex gnat2xml -@cindex XML generation +@node Package Finder Attributes,Package gnatls Attributes,Package Cross_Reference Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager id56}@anchor{1b0}@anchor{gnat_ugn/gnat_project_manager package-finder-attributes}@anchor{1b1} +@subsubsection Package Finder Attributes -@noindent -The @command{gnat2xml} tool is an ASIS-based utility that converts -Ada source code into XML. -@menu -* Switches for gnat2xml:: -* Other Programs:: -* Structure of the XML:: -* Generating Representation Clauses:: -@end menu -@node Switches for gnat2xml -@section Switches for @command{gnat2xml} +@itemize * + +@item +@strong{Default_Switches}: list, indexed, case-insensitive index + +Index is a language name. Value is a list of switches to be used when invoking +@cite{gnatfind} for a source of the language, if there is no applicable +attribute Switches. -@noindent -@command{gnat2xml} takes Ada source code as input, and produces XML -that conforms to the schema. +@item +@strong{Switches}: list, optional index, indexed, case-insensitive index, +others allowed -Usage: +Index is a source file name. Value is the list of switches to be used when +invoking @cite{gnatfind} for the source. +@end itemize -@smallexample -gnat2xml [options] filenames [-files filename] [-cargs gcc_switches] -@end smallexample +@node Package gnatls Attributes,Package IDE Attributes,Package Finder Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager package-gnatls-attributes}@anchor{1b2}@anchor{gnat_ugn/gnat_project_manager id57}@anchor{1b3} +@subsubsection Package gnatls Attributes -@noindent -options: -@smallexample --h ---help -- generate usage information and quit, ignoring all other options ---version -- print version and quit, ignoring all other options --P @file{file} -- indicates the name of the project file that describes - the set of sources to be processed. The exact set of argument - sources depends on other options specified, see below. --U -- if a project file is specified and no argument source is explicitly - specified, process all the units of the closure of the argument project. - Otherwise this option has no effect. +@itemize * --U @var{main_unit} -- if a project file is specified and no argument source - is explicitly specified (either directly or by means of @option{-files} - option), process the closure of units rooted at @var{main_unit}. - Otherwise this option has no effect. +@item +@strong{Switches}: list --X@var{name}=@var{value} -- indicates that external variable @var{name} in - the argument project has the value @var{value}. Has no effect if no - project is specified as tool argument. +Value is a list of switches to be used when invoking @cite{gnatls}. +@end itemize ---RTS=@var{rts-path} -- Specifies the default location of the runtime - library. Same meaning as the equivalent @command{gnatmake} flag - (@pxref{Switches for gnatmake}). ---incremental -- incremental processing on a per-file basis. Source files are - only processed if they have been modified, or if files they depend - on have been modified. This is similar to the way gnatmake/gprbuild - only compiles files that need to be recompiled. A project file - is required in this mode. +@node Package IDE Attributes,Package Install Attributes,Package gnatls Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager id58}@anchor{1b4}@anchor{gnat_ugn/gnat_project_manager package-ide-attributes}@anchor{1b5} +@subsubsection Package IDE Attributes --j@var{n} -- In @option{--incremental} mode, use @var{n} @command{gnat2xml} - processes to perform XML generation in parallel. If @var{n} is 0, then - the maximum number of parallel tree creations is the number of core - processors on the platform. ---output-dir=@var{dir} -- generate one .xml file for each Ada source file, in - directory @file{dir}. (Default is to generate the XML to standard - output.) --I <include-dir> - directories to search for dependencies - You can also set the ADA_INCLUDE_PATH environment variable for this. +@itemize * ---compact -- debugging version, with interspersed source, and a more - compact representation of "sloc". This version does not conform - to any schema. +@item +@strong{Default_Switches}: list, indexed ---rep-clauses -- generate representation clauses (see ``Generating - Representation Clauses'' below). +Index is the name of an external tool that the GNAT Programming System (GPS) +is supporting. Value is a list of switches to use when invoking that tool. --files=filename - the name of a text file containing a list - of Ada source files to process +@item +@strong{Remote_Host}: single --q -- quiet --v -- verbose +Value is a string that designates the remote host in a cross-compilation +environment, to be used for remote compilation and debugging. This attribute +should not be specified when running on the local machine. --cargs ... -- options to pass to gcc -@end smallexample +@item +@strong{Program_Host}: single -@noindent -If a project file is specified and no argument source is explicitly -specified, and no @option{-U} is specified, then the set of processed -sources is all the immediate units of the argument project. +Value is a string that specifies the name of IP address of the embedded target +in a cross-compilation environment, on which the program should execute. -Example: +@item +@strong{Communication_Protocol}: single -@smallexample -gnat2xml -v -output-dir=xml-files *.ad[sb] -@end smallexample - -@noindent -The above will create *.xml files in the @file{xml-files} subdirectory. -For example, if there is an Ada package Mumble.Dumble, whose spec and -body source code lives in mumble-dumble.ads and mumble-dumble.adb, -the above will produce xml-files/mumble-dumble.ads.xml and -xml-files/mumble-dumble.adb.xml. - -@node Other Programs -@section Other Programs - -@noindent -The distribution includes two other programs that are related to -@command{gnat2xml}: - -@command{gnat2xsd} is the schema generator, which generates the schema -to standard output, based on the structure of Ada as encoded by -ASIS. You don't need to run @command{gnat2xsd} in order to use -@command{gnat2xml}. To generate the schema, type: - -@smallexample -gnat2xsd > ada-schema.xsd -@end smallexample - -@noindent -@command{gnat2xml} generates XML files that will validate against -@file{ada-schema.xsd}. - -@command{xml2gnat} is a back-translator that translates the XML back -into Ada source code. The Ada generated by @command{xml2gnat} has -identical semantics to the original Ada code passed to -@command{gnat2xml}. It is not textually identical, however --- for -example, no attempt is made to preserve the original indentation. - -@node Structure of the XML -@section Structure of the XML - -@noindent -The primary documentation for the structure of the XML generated by -@command{gnat2xml} is the schema (see @command{gnat2xsd} above). The -following documentation gives additional details needed to understand -the schema and therefore the XML. - -The elements listed under Defining Occurrences, Usage Occurrences, and -Other Elements represent the syntactic structure of the Ada program. -Element names are given in lower case, with the corresponding element -type Capitalized_Like_This. The element and element type names are -derived directly from the ASIS enumeration type Flat_Element_Kinds, -declared in Asis.Extensions.Flat_Kinds, with the leading ``An_'' or ``A_'' -removed. For example, the ASIS enumeration literal -An_Assignment_Statement corresponds to the XML element -assignment_statement of XML type Assignment_Statement. - -To understand the details of the schema and the corresponding XML, it is -necessary to understand the ASIS standard, as well as the GNAT-specific -extension to ASIS. - -A defining occurrence is an identifier (or character literal or operator -symbol) declared by a declaration. A usage occurrence is an identifier -(or ...) that references such a declared entity. For example, in: - -@smallexample -type T is range 1..10; -X, Y : constant T := 1; -@end smallexample - -@noindent -The first ``T'' is the defining occurrence of a type. The ``X'' is the -defining occurrence of a constant, as is the ``Y'', and the second ``T'' is -a usage occurrence referring to the defining occurrence of T. - -Each element has a 'sloc' (source location), and subelements for each -syntactic subtree, reflecting the Ada grammar as implemented by ASIS. -The types of subelements are as defined in the ASIS standard. For -example, for the right-hand side of an assignment_statement we have -the following comment in asis-statements.ads: - -@smallexample ------------------------------------------------------------------------------- --- 18.3 function Assignment_Expression ------------------------------------------------------------------------------- - - function Assignment_Expression - (Statement : Asis.Statement) - return Asis.Expression; - ------------------------------------------------------------------------------- -... --- Returns the expression from the right hand side of the assignment. -... --- Returns Element_Kinds: --- An_Expression -@end smallexample +Value is the name of the protocol to use to communicate with the target +in a cross-compilation environment, for example @cite{"wtx"} or +@cite{"vxworks"}. -@noindent -The corresponding sub-element of type Assignment_Statement is: +@item +@strong{Compiler_Command}: single, indexed, case-insensitive index -@smallexample -<xsd:element name="assignment_expression_q" type="Expression_Class"/> -@end smallexample +Index is a language Name. Value is a string that denotes the command to be +used to invoke the compiler. The value of @cite{Compiler_Command ("Ada")} is +expected to be compatible with @emph{gnatmake}, in particular in +the handling of switches. -@noindent -where Expression_Class is defined by an xsd:choice of all the -various kinds of expression. +@item +@strong{Debugger_Command}: single -The 'sloc' of each element indicates the starting and ending line and -column numbers. Column numbers are character counts; that is, a tab -counts as 1, not as however many spaces it might expand to. +Value is a string that specifies the name of the debugger to be used, such as +gdb, powerpc-wrs-vxworks-gdb or gdb-4. -Subelements of type Element have names ending in ``_q'' (for ASIS -``Query''), and those of type Element_List end in ``_ql'' (``Query returning -List''). +@item +@strong{gnatlist}: single -Some subelements are ``Boolean''. For example, Private_Type_Definition -has has_abstract_q and has_limited_q, to indicate whether those -keywords are present, as in @code{type T is abstract limited -private;}. False is represented by a Nil_Element. True is represented -by an element type specific to that query (for example, Abstract and -Limited). +Value is a string that specifies the name of the @emph{gnatls} utility +to be used to retrieve information about the predefined path; for example, +@cite{"gnatls"}, @cite{"powerpc-wrs-vxworks-gnatls"}. -The root of the tree is a Compilation_Unit, with attributes: +@item +@strong{VCS_Kind}: single -@itemize @bullet -@item -unit_kind, unit_class, and unit_origin. These are strings that match the -enumeration literals of types Unit_Kinds, Unit_Classes, and Unit_Origins -in package Asis. +Value is a string used to specify the Version Control System (VCS) to be used +for this project, for example "Subversion", "ClearCase". If the +value is set to "Auto", the IDE will try to detect the actual VCS used +on the list of supported ones. -@item -unit_full_name is the full expanded name of the unit, starting from a -root library unit. So for @code{package P.Q.R is ...}, -@code{unit_full_name="P.Q.R"}. Same for @code{separate (P.Q) package R is ...}. +@item +@strong{VCS_File_Check}: single -@item -def_name is the same as unit_full_name for library units; for subunits, -it is just the simple name. +Value is a string that specifies the command used by the VCS to check +the validity of a file, either when the user explicitly asks for a check, +or as a sanity check before doing the check-in. -@item -source_file is the name of the Ada source file. For example, for -the spec of @code{P.Q.R}, @code{source_file="p-q-r.ads"}. This allows one to -interpret the source locations --- the ``sloc'' of all elements -within this Compilation_Unit refers to line and column numbers -within the named file. +@item +@strong{VCS_Log_Check}: single + +Value is a string that specifies the command used by the VCS to check +the validity of a log file. + +@item +@strong{Documentation_Dir}: single + +Value is the directory used to generate the documentation of source code. @end itemize -@noindent -Defining occurrences have these attributes: +@node Package Install Attributes,Package Linker Attributes,Package IDE Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager package-install-attributes}@anchor{1b6}@anchor{gnat_ugn/gnat_project_manager id59}@anchor{1b7} +@subsubsection Package Install Attributes -@itemize @bullet -@item -def_name is the simple name of the declared entity, as written in the Ada -source code. -@item -def is a unique URI of the form: - ada://kind/fully/qualified/name +@itemize * -where: +@item +@strong{Artifacts}: list, indexed - kind indicates the kind of Ada entity being declared (see below), and +An array attribute to declare a set of files not part of the sources +to be installed. The array discriminant is the directory where the +file is to be installed. If a relative directory then Prefix (see +below) is prepended. - fully/qualified/name, is the fully qualified name of the Ada - entity, with each of ``fully'', ``qualified'', and ``name'' being - mangled for uniqueness. We do not document the mangling - algorithm, which is subject to change; we just guarantee that the - names are unique in the face of overloading. +@item +@strong{Prefix}: single -@item -type is the type of the declared object, or @code{null} for -declarations of things other than objects. +Value is the install destination directory. + +@item +@strong{Sources_Subdir}: single + +Value is the sources directory or subdirectory of Prefix. + +@item +@strong{Exec_Subdir}: single + +Value is the executables directory or subdirectory of Prefix. + +@item +@strong{Lib_Subdir}: single + +Value is library directory or subdirectory of Prefix. + +@item +@strong{Project_Subdir}: single + +Value is the project directory or subdirectory of Prefix. + +@item +@strong{Active}: single + +Indicates that the project is to be installed or not. Case-insensitive value +"false" means that the project is not to be installed, all other values mean +that the project is to be installed. + +@item +@strong{Mode}: single + +Value is the installation mode, it is either @strong{dev} (default) or @strong{usage}. + +@item +@strong{Install_Name}: single + +Specify the name to use for recording the installation. The default is +the project name without the extension. @end itemize -@noindent -Usage occurrences have these attributes: +@node Package Linker Attributes,Package Naming Attributes,Package Install Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager id60}@anchor{1b8}@anchor{gnat_ugn/gnat_project_manager package-linker-attributes}@anchor{1b9} +@subsubsection Package Linker Attributes -@itemize @bullet -@item -ref_name is the same as the def_name of the corresponding defining -occurrence. This attribute is not of much use, because of -overloading; use ref for lookups, instead. -@item -ref is the same as the def of the corresponding defining -occurrence. + +@itemize * + +@item +@strong{General} + + +@itemize * + +@item +@strong{Required_Switches}: list + +Value is a list of switches that are required when invoking the linker to link +an executable. + +@item +@strong{Default_Switches}: list, indexed, case-insensitive index + +Index is a language name. Value is a list of switches for the linker when +linking an executable for a main source of the language, when there is no +applicable Switches. + +@item +@strong{Leading_Switches}: list, optional index, indexed, +case-insensitive index, others allowed + +Index is a source file name or a language name. Value is the list of switches +to be used at the beginning of the command line when invoking the linker to +build an executable for the source or for its language. + +@item +@strong{Switches}: list, optional index, indexed, case-insensitive index, +others allowed + +Index is a source file name or a language name. Value is the list of switches +to be used when invoking the linker to build an executable for the source or +for its language. + +@item +@strong{Trailing_Switches}: list, optional index, indexed, +case-insensitive index, others allowed + +Index is a source file name or a language name. Value is the list of switches +to be used at the end of the command line when invoking the linker to +build an executable for the source or for its language. These switches may +override the Required_Switches. + +@item +@strong{Linker_Options}: list + +Value is a list of switches/options that are to be added when linking an +executable from a project importing the current project directly or indirectly. +Linker_Options are not used when linking an executable from the current +project. + +@item +@strong{Map_File_Option}: single + +Value is the switch to specify the map file name that the linker needs to +create. @end itemize -@noindent -In summary, @code{def_name} and @code{ref_name} are as in the source -code of the declaration, possibly overloaded, whereas @code{def} and -@code{ref} are unique-ified. +@item +@strong{Configuration - Linking} -Literal elements have this attribute: -@itemize @bullet -@item -lit_val is the value of the literal as written in the source text, -appropriately escaped (e.g. @code{"} ---> @code{"}). This applies -only to numeric and string literals. Enumeration literals in Ada are -not really "literals" in the usual sense; they are usage occurrences, -and have ref_name and ref as described above. Note also that string -literals used as operator symbols are treated as defining or usage -occurrences, not as literals. +@itemize * + +@item +@strong{Driver}: single + +Value is the name of the linker executable. @end itemize -@noindent -Elements that can syntactically represent names and expressions (which -includes usage occurrences, plus function calls and so forth) have this -attribute: +@item +@strong{Configuration - Response Files} -@itemize @bullet -@item -type. If the element represents an expression or the name of an object, -'type' is the 'def' for the defining occurrence of the type of that -expression or name. Names of other kinds of entities, such as package -names and type names, do not have a type in Ada; these have type="null" -in the XML. + +@itemize * + +@item +@strong{Max_Command_Line_Length}: single + +Value is the maximum number of character in the command line when invoking +the linker to link an executable. + +@item +@strong{Response_File_Format}: single + +Indicates the kind of response file to create when the length of the linking +command line is too large. Only authorized case-insensitive values are "none", +"gnu", "object_list", "gcc_gnu", "gcc_option_list" and "gcc_object_list". + +@item +@strong{Response_File_Switches}: list + +Value is the list of switches to specify a response file to the linker. +@end itemize @end itemize -@noindent -Pragma elements have this attribute: +@c only PRO or GPL +@c +@c .. _Package_Metrics_Attribute: +@c +@c Package Metrics Attribute +@c ^^^^^^^^^^^^^^^^^^^^^^^^^ +@c +@c * **Default_Switches**: list, indexed, case-insensitive index +@c +@c Index is a language name. Value is a list of switches to be used when invoking +@c `gnatmetric` for a source of the language, if there is no applicable +@c attribute Switches. +@c +@c * **Switches**: list, optional index, indexed, case-insensitive index, +@c others allowed +@c +@c Index is a source file name. Value is the list of switches to be used when +@c invoking `gnatmetric` for the source. -@itemize @bullet -@item -pragma_name is the name of the pragma. For language-defined pragmas, the -pragma name is redundant with the element kind (for example, an -assert_pragma element necessarily has pragma_name="Assert"). However, all -implementation-defined pragmas are lumped together in ASIS as a single -element kind (for example, the GNAT-specific pragma Unreferenced is -represented by an implementation_defined_pragma element with -pragma_name="Unreferenced"). +@node Package Naming Attributes,Package Remote Attributes,Package Linker Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager package-naming-attributes}@anchor{1ba}@anchor{gnat_ugn/gnat_project_manager id61}@anchor{1bb} +@subsubsection Package Naming Attributes + + + +@itemize * + +@item +@strong{Specification_Suffix}: single, indexed, case-insensitive index + +Equivalent to attribute Spec_Suffix. + +@item +@strong{Spec_Suffix}: single, indexed, case-insensitive index + +Index is a language name. Value is the extension of file names for specs of +the language. + +@item +@strong{Implementation_Suffix}: single, indexed, case-insensitive index + +Equivalent to attribute Body_Suffix. + +@item +@strong{Body_Suffix}: single, indexed, case-insensitive index + +Index is a language name. Value is the extension of file names for bodies of +the language. + +@item +@strong{Separate_Suffix}: single + +Value is the extension of file names for subunits of Ada. + +@item +@strong{Casing}: single + +Indicates the casing of sources of the Ada language. Only authorized +case-insensitive values are "lowercase", "uppercase" and "mixedcase". + +@item +@strong{Dot_Replacement}: single + +Value is the string that replace the dot of unit names in the source file names +of the Ada language. + +@item +@strong{Specification}: single, optional index, indexed, +case-insensitive index + +Equivalent to attribute Spec. + +@item +@strong{Spec}: single, optional index, indexed, case-insensitive index + +Index is a unit name. Value is the file name of the spec of the unit. + +@item +@strong{Implementation}: single, optional index, indexed, +case-insensitive index + +Equivalent to attribute Body. + +@item +@strong{Body}: single, optional index, indexed, case-insensitive index + +Index is a unit name. Value is the file name of the body of the unit. + +@item +@strong{Specification_Exceptions}: list, indexed, case-insensitive index + +Index is a language name. Value is a list of specs for the language that do not +necessarily follow the naming scheme for the language and that may or may not +be found in the source directories of the project. + +@item +@strong{Implementation_Exceptions}: list, indexed, case-insensitive index + +Index is a language name. Value is a list of bodies for the language that do not +necessarily follow the naming scheme for the language and that may or may not +be found in the source directories of the project. @end itemize -@noindent -Defining occurrences of formal parameters and generic formal objects have this -attribute: -@itemize @bullet -@item -mode indicates that the parameter is of mode 'in', 'in out', or 'out'. +@node Package Remote Attributes,Package Stack Attributes,Package Naming Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager package-remote-attributes}@anchor{1bc}@anchor{gnat_ugn/gnat_project_manager id63}@anchor{1bd} +@subsubsection Package Remote Attributes + + + +@itemize * + +@item +@strong{Included_Patterns}: list + +If this attribute is defined it sets the patterns to +synchronized from the master to the slaves. It is exclusive +with Excluded_Patterns, that is it is an error to define +both. + +@item +@strong{Included_Artifact_Patterns}: list + +If this attribute is defined it sets the patterns of compilation +artifacts to synchronized from the slaves to the build master. +This attribute replace the default hard-coded patterns. + +@item +@strong{Excluded_Patterns}: list + +Set of patterns to ignore when synchronizing sources from the build +master to the slaves. A set of predefined patterns are supported +(e.g. *.o, *.ali, *.exe, etc.), this attributes make it possible to +add some more patterns. + +@item +@strong{Root_Dir}: single + +Value is the root directory used by the slave machines. @end itemize -@noindent -All elements other than Not_An_Element have this attribute: +@node Package Stack Attributes,Package Synchronize Attributes,Package Remote Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager id64}@anchor{1be}@anchor{gnat_ugn/gnat_project_manager package-stack-attributes}@anchor{1bf} +@subsubsection Package Stack Attributes -@itemize @bullet -@item -checks is a comma-separated list of run-time checks that are needed -for that element. The possible checks are: do_accessibility_check, -do_discriminant_check,do_division_check,do_length_check, -do_overflow_check,do_range_check,do_storage_check,do_tag_check. + + +@itemize * + +@item +@strong{Switches}: list + +Value is the list of switches to be used when invoking @cite{gnatstack}. @end itemize -@noindent -The "kind" part of the "def" and "ref" attributes is taken from the ASIS -enumeration type Flat_Declaration_Kinds, declared in -Asis.Extensions.Flat_Kinds, with the leading "An_" or "A_" removed, and -any trailing "_Declaration" or "_Specification" removed. Thus, the -possible kinds are as follows: - -@smallexample -ordinary_type -task_type -protected_type -incomplete_type -tagged_incomplete_type -private_type -private_extension -subtype -variable -constant -deferred_constant -single_task -single_protected -integer_number -real_number -enumeration_literal -discriminant -component -loop_parameter -generalized_iterator -element_iterator -procedure -function -parameter -procedure_body -function_body -return_variable -return_constant -null_procedure -expression_function -package -package_body -object_renaming -exception_renaming -package_renaming -procedure_renaming -function_renaming -generic_package_renaming -generic_procedure_renaming -generic_function_renaming -task_body -protected_body -entry -entry_body -entry_index -procedure_body_stub -function_body_stub -package_body_stub -task_body_stub -protected_body_stub -exception -choice_parameter -generic_procedure -generic_function -generic_package -package_instantiation -procedure_instantiation -function_instantiation -formal_object -formal_type -formal_incomplete_type -formal_procedure -formal_function -formal_package -formal_package_declaration_with_box -@end smallexample - -@node Generating Representation Clauses -@section Generating Representation Clauses - -@noindent -If the @option{--rep-clauses} switch is given, @command{gnat2xml} will -generate representation clauses for certain types showing the -representation chosen by the compiler. The information is produced by -the ASIS ``Data Decomposition'' facility --- see the -@code{Asis.Data_Decomposition} package for details. - -Not all types are supported. For example, @code{Type_Model_Kind} must -be @code{A_Simple_Static_Model}. Types declared within generic units -have no representation. The clauses that are generated include -@code{attribute_definition_clauses} for @code{Size} and -@code{Component_Size}, as well as -@code{record_representation_clauses}. - -There is no guarantee that the generated representation clauses could -have actually come from legal Ada code; Ada has some restrictions that -are not necessarily obeyed by the generated clauses. - -The representation clauses are surrounded by comment elements to -indicate that they are automatically generated, something like this: - -@smallexample -<comment text="--gen+"> -... -<attribute_definition_clause> -... -<comment text="--gen-"> -... -@end smallexample +@node Package Synchronize Attributes,,Package Stack Attributes,Attributes +@anchor{gnat_ugn/gnat_project_manager package-synchronize-attributes}@anchor{1c0} +@subsubsection Package Synchronize Attributes -@end ifclear -@ifclear FSFEDITION -@c ********************************* -@node The GNAT Metrics Tool gnatmetric -@chapter The GNAT Metrics Tool @command{gnatmetric} -@findex gnatmetric -@cindex Metric tool -@noindent -The @command{gnatmetric} tool is an ASIS-based utility -for computing various program metrics. -It takes an Ada source file as input and generates a file containing the -metrics data as output. Various switches control which -metrics are computed and output. +@itemize * -@menu -* Switches for gnatmetric:: -@end menu +@item +@strong{Default_Switches}: list, indexed, case-insensitive index -To compute program metrics, @command{gnatmetric} invokes the Ada -compiler and generates and uses the ASIS tree for the input source; -thus the input must be legal Ada code, and the tool should have all the -information needed to compile the input source. To provide this information, -you may specify as a tool parameter the project file the input source belongs to -(or you may call @command{gnatmetric} -through the @command{gnat} driver (see @ref{The GNAT Driver and -Project Files}). Another possibility is to specify the source search -path and needed configuration files in @option{-cargs} section of @command{gnatmetric} -call, see the description of the @command{gnatmetric} switches below. - -If the set of sources to be processed by @code{gnatmetric} contains sources with -preprocessing directives -then the needed options should be provided to run preprocessor as a part of -the @command{gnatmetric} call, and the computed metrics -will correspond to preprocessed sources. - - -The @command{gnatmetric} command has the form - -@smallexample -@c $ gnatmetric @ovar{switches} @{@var{filename}@} @r{[}-cargs @var{gcc_switches}@r{]} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatmetric @r{[}@var{switches}@r{]} @{@var{filename}@} @r{[}-cargs @var{gcc_switches}@r{]} -@end smallexample - -@noindent -where -@itemize @bullet -@item -@var{switches} specify the metrics to compute and define the destination for -the output +Index is a language name. Value is a list of switches to be used when invoking +@cite{gnatsync} for a source of the language, if there is no applicable +attribute Switches. -@item -Each @var{filename} is the name (including the extension) of a source -file to process. ``Wildcards'' are allowed, and -the file name may contain path information. -If no @var{filename} is supplied, then the @var{switches} list must contain -at least one -@option{-files} switch (@pxref{Other gnatmetric Switches}). -Including both a @option{-files} switch and one or more -@var{filename} arguments is permitted. +@item +@strong{Switches}: list, optional index, indexed, case-insensitive index, +others allowed -@item -@samp{@var{gcc_switches}} is a list of switches for -@command{gcc}. They will be passed on to all compiler invocations made by -@command{gnatmetric} to generate the ASIS trees. Here you can provide -@option{-I} switches to form the source search path, -and use the @option{-gnatec} switch to set the configuration file, -use the @option{-gnat05} switch if sources should be compiled in -Ada 2005 mode etc. +Index is a source file name. Value is the list of switches to be used when +invoking @cite{gnatsync} for the source. @end itemize -@node Switches for gnatmetric -@section Switches for @command{gnatmetric} +@node Tools Supporting Project Files,GNAT Utility Programs,GNAT Project Manager,Top +@anchor{gnat_ugn/tools_supporting_project_files doc}@anchor{1c1}@anchor{gnat_ugn/tools_supporting_project_files tools-supporting-project-files}@anchor{c}@anchor{gnat_ugn/tools_supporting_project_files id1}@anchor{1c2} +@chapter Tools Supporting Project Files + -@noindent -The following subsections describe the various switches accepted by -@command{gnatmetric}, organized by category. +This section describes how project files can be used in conjunction with a number of +GNAT tools. @menu -* Output Files Control:: -* Disable Metrics For Local Units:: -* Specifying a set of metrics to compute:: -* Other gnatmetric Switches:: -@ignore -* Generate project-wide metrics:: -@end ignore +* gnatmake and Project Files:: +* The GNAT Driver and Project Files:: + @end menu -@node Output Files Control -@subsection Output File Control -@cindex Output file control in @command{gnatmetric} - -@noindent -@command{gnatmetric} has two output formats. It can generate a -textual (human-readable) form, and also XML. By default only textual -output is generated. - -When generating the output in textual form, @command{gnatmetric} creates -for each Ada source file a corresponding text file -containing the computed metrics, except for the case when the set of metrics -specified by gnatmetric parameters consists only of metrics that are computed -for the whole set of analyzed sources, but not for each Ada source. -By default, the name of the file containing metric information for a source -is obtained by appending the @file{.metrix} suffix to the -name of the input source file. If not otherwise specified and no project file -is specified as @command{gnatmetric} option this file is placed in the same -directory as where the source file is located. If @command{gnatmetric} has a -project file as its parameter, it places all the generated files in the -object directory of the project (or in the project source directory if the -project does not define an objects directory), if @option{--subdirs} option -is specified, the files are placed in the subrirectory of this directory -specified by this option. - -All the output information generated in XML format is placed in a single -file. By default the name of this file is @file{metrix.xml}. -If not otherwise specified and if no project file is specified -as @command{gnatmetric} option this file is placed in the -current directory. - -Some of the computed metrics are summed over the units passed to -@command{gnatmetric}; for example, the total number of lines of code. -By default this information is sent to @file{stdout}, but a file -can be specified with the @option{-og} switch. - -The following switches control the @command{gnatmetric} output: - -@table @option -@cindex @option{-x} (@command{gnatmetric}) -@item -x -Generate the XML output - -@cindex @option{-xs} (@command{gnatmetric}) -@item -xs -Generate the XML output and the XML schema file that describes the structure -of the XML metric report, this schema is assigned to the XML file. The schema -file has the same name as the XML output file with @file{.xml} suffix replaced -with @file{.xsd} - -@cindex @option{-nt} (@command{gnatmetric}) -@item -nt -Do not generate the output in text form (implies @option{-x}) - -@cindex @option{-d} (@command{gnatmetric}) -@item -d @var{output_dir} -Put text files with detailed metrics into @var{output_dir} - -@cindex @option{-o} (@command{gnatmetric}) -@item -o @var{file_suffix} -Use @var{file_suffix}, instead of @file{.metrix} -in the name of the output file. - -@cindex @option{-og} (@command{gnatmetric}) -@item -og @var{file_name} -Put global metrics into @var{file_name} - -@cindex @option{-ox} (@command{gnatmetric}) -@item -ox @var{file_name} -Put the XML output into @var{file_name} (also implies @option{-x}) - -@cindex @option{-sfn} (@command{gnatmetric}) -@item -sfn -Use ``short'' source file names in the output. (The @command{gnatmetric} -output includes the name(s) of the Ada source file(s) from which the metrics -are computed. By default each name includes the absolute path. The -@option{-sfn} switch causes @command{gnatmetric} -to exclude all directory information from the file names that are output.) - -@end table - -@node Disable Metrics For Local Units -@subsection Disable Metrics For Local Units -@cindex Disable Metrics For Local Units in @command{gnatmetric} - -@noindent -@command{gnatmetric} relies on the GNAT compilation model @minus{} -one compilation -unit per one source file. It computes line metrics for the whole source -file, and it also computes syntax -and complexity metrics for the file's outermost unit. - -By default, @command{gnatmetric} will also compute all metrics for certain -kinds of locally declared program units: - -@itemize @bullet -@item -subprogram (and generic subprogram) bodies; +@node gnatmake and Project Files,The GNAT Driver and Project Files,,Tools Supporting Project Files +@anchor{gnat_ugn/tools_supporting_project_files id2}@anchor{1c3}@anchor{gnat_ugn/tools_supporting_project_files gnatmake-and-project-files}@anchor{e1} +@section gnatmake and Project Files -@item -package (and generic package) specs and bodies; -@item -task object and type specifications and bodies; +This section covers several topics related to @emph{gnatmake} and +project files: defining switches for @emph{gnatmake} +and for the tools that it invokes; specifying configuration pragmas; +the use of the @cite{Main} attribute; building and rebuilding library project +files. -@item -protected object and type specifications and bodies. -@end itemize +@menu +* Switches Related to Project Files:: +* Switches and Project Files:: +* Specifying Configuration Pragmas:: +* Project Files and Main Subprograms:: +* Library Project Files:: + +@end menu + +@node Switches Related to Project Files,Switches and Project Files,,gnatmake and Project Files +@anchor{gnat_ugn/tools_supporting_project_files switches-related-to-project-files}@anchor{e3}@anchor{gnat_ugn/tools_supporting_project_files id3}@anchor{1c4} +@subsection Switches Related to Project Files + + +The following switches are used by GNAT tools that support project files: + +@quotation + +@geindex -P (any project-aware tool) +@end quotation -@noindent -These kinds of entities will be referred to as -@emph{eligible local program units}, or simply @emph{eligible local units}, -@cindex Eligible local unit (for @command{gnatmetric}) -in the discussion below. -Note that a subprogram declaration, generic instantiation, -or renaming declaration only receives metrics -computation when it appear as the outermost entity -in a source file. +@table @asis -Suppression of metrics computation for eligible local units can be -obtained via the following switch: +@item @code{-P@emph{project}} -@table @option -@cindex @option{-nolocal} (@command{gnatmetric}) -@item -nolocal -Do not compute detailed metrics for eligible local program units +Indicates the name of a project file. This project file will be parsed with +the verbosity indicated by @emph{-vP*x*}, +if any, and using the external references indicated +by @emph{-X} switches, if any. +There may zero, one or more spaces between @emph{-P} and @cite{project}. +There must be only one @emph{-P} switch on the command line. + +Since the Project Manager parses the project file only after all the switches +on the command line are checked, the order of the switches +@emph{-P}, +@emph{-vP*x*} +or @emph{-X} is not significant. + +@geindex -X (any project-aware tool) + +@item @code{-X@emph{name}=@emph{value}} + +Indicates that external variable @cite{name} has the value @cite{value}. +The Project Manager will use this value for occurrences of +@cite{external(name)} when parsing the project file. + +If @cite{name} or @cite{value} includes a space, then @cite{name=value} should be +put between quotes. + +@example +-XOS=NT +-X"user=John Doe" +@end example + +Several @emph{-X} switches can be used simultaneously. +If several @emph{-X} switches specify the same +@cite{name}, only the last one is used. + +An external variable specified with a @emph{-X} switch +takes precedence over the value of the same name in the environment. + +@geindex -vP (any project-aware tool) + +@item @code{-vP@emph{x}} + +Indicates the verbosity of the parsing of GNAT project files. + +@emph{-vP0} means Default; +@emph{-vP1} means Medium; +@emph{-vP2} means High. + +The default is Default: no output for syntactically correct +project files. +If several @emph{-vP*x*} switches are present, +only the last one is used. + +@geindex -aP (any project-aware tool) + +@item @code{-aP@emph{dir}} + +Add directory @cite{dir} at the beginning of the project search path, in order, +after the current working directory. + +@geindex -eL (any project-aware tool) + +@item @code{-eL} + +Follow all symbolic links when processing project files. + +@geindex --subdirs= (gnatmake and gnatclean) + +@item @code{--subdirs=@emph{subdir}} + +This switch is recognized by @emph{gnatmake} and @emph{gnatclean}. It +indicate that the real directories (except the source directories) are the +subdirectories @cite{subdir} of the directories specified in the project files. +This applies in particular to object directories, library directories and +exec directories. If the subdirectories do not exist, they are created +automatically. @end table -@node Specifying a set of metrics to compute -@subsection Specifying a set of metrics to compute +@node Switches and Project Files,Specifying Configuration Pragmas,Switches Related to Project Files,gnatmake and Project Files +@anchor{gnat_ugn/tools_supporting_project_files id4}@anchor{1c5}@anchor{gnat_ugn/tools_supporting_project_files switches-and-project-files}@anchor{1c6} +@subsection Switches and Project Files -@noindent -By default all the metrics are computed and reported. The switches -described in this subsection allow you to control, on an individual -basis, whether metrics are computed and -reported. If at least one positive metric -switch is specified (that is, a switch that defines that a given -metric or set of metrics is to be computed), then only -explicitly specified metrics are reported. -@menu -* Line Metrics Control:: -* Syntax Metrics Control:: -* Complexity Metrics Control:: -* Coupling Metrics Control:: -@end menu +For each of the packages @cite{Builder}, @cite{Compiler}, @cite{Binder}, and +@cite{Linker}, you can specify a @cite{Default_Switches} +attribute, a @cite{Switches} attribute, or both; +as their names imply, these switch-related +attributes affect the switches that are used for each of these GNAT +components when +@emph{gnatmake} is invoked. As will be explained below, these +component-specific switches precede +the switches provided on the @emph{gnatmake} command line. -@node Line Metrics Control -@subsubsection Line Metrics Control -@cindex Line metrics control in @command{gnatmetric} +The @cite{Default_Switches} attribute is an attribute +indexed by language name (case insensitive) whose value is a string list. +For example: -@noindent -For any (legal) source file, and for each of its -eligible local program units, @command{gnatmetric} computes the following -metrics: +@quotation -@itemize @bullet -@item -the total number of lines; +@example +package Compiler is + for Default_Switches ("Ada") + use ("-gnaty", + "-v"); +end Compiler; +@end example +@end quotation -@item -the total number of code lines (i.e., non-blank lines that are not comments) +The @cite{Switches} attribute is indexed on a file name (which may or may +not be case sensitive, depending +on the operating system) whose value is a string list. For example: -@item -the number of comment lines +@quotation -@item -the number of code lines containing end-of-line comments; +@example +package Builder is + for Switches ("main1.adb") + use ("-O2"); + for Switches ("main2.adb") + use ("-g"); +end Builder; +@end example +@end quotation -@item -the comment percentage: the ratio between the number of lines that contain -comments and the number of all non-blank lines, expressed as a percentage; +For the @cite{Builder} package, the file names must designate source files +for main subprograms. For the @cite{Binder} and @cite{Linker} packages, the +file names must designate @code{ALI} or source files for main subprograms. +In each case just the file name without an explicit extension is acceptable. -@item -the number of empty lines and lines containing only space characters and/or -format effectors (blank lines) +For each tool used in a program build (@emph{gnatmake}, the compiler, the +binder, and the linker), the corresponding package @@dfn@{contributes@} a set of +switches for each file on which the tool is invoked, based on the +switch-related attributes defined in the package. +In particular, the switches +that each of these packages contributes for a given file @cite{f} comprise: -@item -the average number of code lines in subprogram bodies, task bodies, entry -bodies and statement sequences in package bodies (this metric is only computed -across the whole set of the analyzed units) +@itemize * + +@item +the value of attribute @cite{Switches (`f})`, +if it is specified in the package for the given file, + +@item +otherwise, the value of @cite{Default_Switches ("Ada")}, +if it is specified in the package. @end itemize -@noindent -@command{gnatmetric} sums the values of the line metrics for all the -files being processed and then generates the cumulative results. The tool -also computes for all the files being processed the average number of code -lines in bodies. +If neither of these attributes is defined in the package, then the package does +not contribute any switches for the given file. -You can use the following switches to select the specific line metrics -to be computed and reported. +When @emph{gnatmake} is invoked on a file, the switches comprise +two sets, in the following order: those contributed for the file +by the @cite{Builder} package; +and the switches passed on the command line. -@table @option -@cindex @option{--lines@var{x}} (@command{gnatmetric}) +When @emph{gnatmake} invokes a tool (compiler, binder, linker) on a file, +the switches passed to the tool comprise three sets, +in the following order: -@cindex @option{--no-lines@var{x}} -@item --lines-all -Report all the line metrics +@itemize * -@item --no-lines-all -Do not report any of line metrics +@item +the applicable switches contributed for the file +by the @cite{Builder} package in the project file supplied on the command line; -@item --lines -Report the number of all lines +@item +those contributed for the file by the package (in the relevant project file -- +see below) corresponding to the tool; and -@item --no-lines -Do not report the number of all lines +@item +the applicable switches passed on the command line. +@end itemize -@item --lines-code -Report the number of code lines +The term @emph{applicable switches} reflects the fact that +@emph{gnatmake} switches may or may not be passed to individual +tools, depending on the individual switch. -@item --no-lines-code -Do not report the number of code lines +@emph{gnatmake} may invoke the compiler on source files from different +projects. The Project Manager will use the appropriate project file to +determine the @cite{Compiler} package for each source file being compiled. +Likewise for the @cite{Binder} and @cite{Linker} packages. -@item --lines-comment -Report the number of comment lines +As an example, consider the following package in a project file: -@item --no-lines-comment -Do not report the number of comment lines +@quotation -@item --lines-eol-comment -Report the number of code lines containing -end-of-line comments +@example +project Proj1 is + package Compiler is + for Default_Switches ("Ada") + use ("-g"); + for Switches ("a.adb") + use ("-O1"); + for Switches ("b.adb") + use ("-O2", + "-gnaty"); + end Compiler; +end Proj1; +@end example +@end quotation -@item --no-lines-eol-comment -Do not report the number of code lines containing -end-of-line comments +If @emph{gnatmake} is invoked with this project file, and it needs to +compile, say, the files @code{a.adb}, @code{b.adb}, and @code{c.adb}, then +@code{a.adb} will be compiled with the switch @emph{-O1}, +@code{b.adb} with switches @emph{-O2} and @emph{-gnaty}, +and @code{c.adb} with @emph{-g}. -@item --lines-ratio -Report the comment percentage in the program text +The following example illustrates the ordering of the switches +contributed by different packages: -@item --no-lines-ratio -Do not report the comment percentage in the program text +@quotation -@item --lines-blank -Report the number of blank lines +@example +project Proj2 is + package Builder is + for Switches ("main.adb") + use ("-g", + "-O1", + "-f"); + end Builder; + + package Compiler is + for Switches ("main.adb") + use ("-O2"); + end Compiler; +end Proj2; +@end example +@end quotation -@item --no-lines-blank -Do not report the number of blank lines +If you issue the command: -@item --lines-average -Report the average number of code lines in subprogram bodies, task bodies, -entry bodies and statement sequences in package bodies. The metric is computed -and reported for the whole set of processed Ada sources only. +@quotation -@item --no-lines-average -Do not report the average number of code lines in subprogram bodies, -task bodies, entry bodies and statement sequences in package bodies. +@example +$ gnatmake -Pproj2 -O0 main +@end example +@end quotation -@end table +then the compiler will be invoked on @code{main.adb} with the following +sequence of switches -@node Syntax Metrics Control -@subsubsection Syntax Metrics Control -@cindex Syntax metrics control in @command{gnatmetric} +@quotation -@noindent -@command{gnatmetric} computes various syntactic metrics for the -outermost unit and for each eligible local unit: +@example +-g -O1 -O2 -O0 +@end example +@end quotation -@table @emph -@item LSLOC (``Logical Source Lines Of Code'') -The total number of declarations and the total number of statements. Note -that the definition of declarations is the one given in the reference -manual: +with the last @emph{-O} +switch having precedence over the earlier ones; +several other switches +(such as @emph{-c}) are added implicitly. -@noindent -``Each of the following is defined to be a declaration: any basic_declaration; -an enumeration_literal_specification; a discriminant_specification; -a component_declaration; a loop_parameter_specification; a -parameter_specification; a subprogram_body; an entry_declaration; -an entry_index_specification; a choice_parameter_specification; -a generic_formal_parameter_declaration.'' +The switches @emph{-g} +and @emph{-O1} are contributed by package +@cite{Builder}, @emph{-O2} is contributed +by the package @cite{Compiler} +and @emph{-O0} comes from the command line. -This means for example that each enumeration literal adds one to the count, -as well as each subprogram parameter. +The @emph{-g} switch will also be passed in the invocation of +@emph{Gnatlink.} -Thus the results from this metric will be significantly greater than might -be expected from a naive view of counting semicolons. +A final example illustrates switch contributions from packages in different +project files: -@item Maximal static nesting level of inner program units -According to -@cite{Ada Reference Manual}, 10.1(1), ``A program unit is either a -package, a task unit, a protected unit, a -protected entry, a generic unit, or an explicitly declared subprogram other -than an enumeration literal.'' +@quotation -@item Maximal nesting level of composite syntactic constructs -This corresponds to the notion of the -maximum nesting level in the GNAT built-in style checks -(@pxref{Style Checking}) -@end table +@example +project Proj3 is + for Source_Files use ("pack.ads", "pack.adb"); + package Compiler is + for Default_Switches ("Ada") + use ("-gnata"); + end Compiler; +end Proj3; + +with "Proj3"; +project Proj4 is + for Source_Files use ("foo_main.adb", "bar_main.adb"); + package Builder is + for Switches ("foo_main.adb") + use ("-s", + "-g"); + end Builder; +end Proj4; +@end example + +@example +-- Ada source file: +with Pack; +procedure Foo_Main is + ... +end Foo_Main; +@end example +@end quotation -@noindent -For the outermost unit in the file, @command{gnatmetric} additionally computes -the following metrics: +If the command is -@table @emph -@item Public subprograms -This metric is computed for package specs. It is the -number of subprograms and generic subprograms declared in the visible -part (including the visible part of nested packages, protected objects, and -protected types). +@quotation -@item All subprograms -This metric is computed for bodies and subunits. The -metric is equal to a total number of subprogram bodies in the compilation -unit. -Neither generic instantiations nor renamings-as-a-body nor body stubs -are counted. Any subprogram body is counted, independently of its nesting -level and enclosing constructs. Generic bodies and bodies of protected -subprograms are counted in the same way as ``usual'' subprogram bodies. - -@item Public types -This metric is computed for package specs and -generic package declarations. It is the total number of types -that can be referenced from outside this compilation unit, plus the -number of types from all the visible parts of all the visible generic -packages. Generic formal types are not counted. Only types, not subtypes, -are included. - -@noindent -Along with the total number of public types, the following -types are counted and reported separately: - -@itemize @bullet -@item -Abstract types +@example +$ gnatmake -PProj4 foo_main.adb -cargs -gnato +@end example +@end quotation -@item -Root tagged types (abstract, non-abstract, private, non-private). Type -extensions are @emph{not} counted +then the switches passed to the compiler for @code{foo_main.adb} are +@emph{-g} (contributed by the package @cite{Proj4.Builder}) and +@emph{-gnato} (passed on the command line). +When the imported package @cite{Pack} is compiled, the switches used +are @emph{-g} from @cite{Proj4.Builder}, +@emph{-gnata} (contributed from package @cite{Proj3.Compiler}, +and @emph{-gnato} from the command line. -@item -Private types (including private extensions) +When using @emph{gnatmake} with project files, some switches or +arguments may be expressed as relative paths. As the working directory where +compilation occurs may change, these relative paths are converted to absolute +paths. For the switches found in a project file, the relative paths +are relative to the project file directory, for the switches on the command +line, they are relative to the directory where @emph{gnatmake} is invoked. +The switches for which this occurs are: +-I, +-A, +-L, +-aO, +-aL, +-aI, as well as all arguments that are not switches (arguments to +switch +-o, object files specified in package @cite{Linker} or after +-largs on the command line). The exception to this rule is the switch +--RTS= for which a relative path argument is never converted. -@item -Task types +@node Specifying Configuration Pragmas,Project Files and Main Subprograms,Switches and Project Files,gnatmake and Project Files +@anchor{gnat_ugn/tools_supporting_project_files id5}@anchor{1c7}@anchor{gnat_ugn/tools_supporting_project_files specifying-configuration-pragmas}@anchor{7d} +@subsection Specifying Configuration Pragmas -@item -Protected types +When using @emph{gnatmake} with project files, if there exists a file +@code{gnat.adc} that contains configuration pragmas, this file will be +ignored. + +Configuration pragmas can be defined by means of the following attributes in +project files: @cite{Global_Configuration_Pragmas} in package @cite{Builder} +and @cite{Local_Configuration_Pragmas} in package @cite{Compiler}. + +Both these attributes are single string attributes. Their values is the path +name of a file containing configuration pragmas. If a path name is relative, +then it is relative to the project directory of the project file where the +attribute is defined. + +When compiling a source, the configuration pragmas used are, in order, +those listed in the file designated by attribute +@cite{Global_Configuration_Pragmas} in package @cite{Builder} of the main +project file, if it is specified, and those listed in the file designated by +attribute @cite{Local_Configuration_Pragmas} in package @cite{Compiler} of +the project file of the source, if it exists. + +@node Project Files and Main Subprograms,Library Project Files,Specifying Configuration Pragmas,gnatmake and Project Files +@anchor{gnat_ugn/tools_supporting_project_files id6}@anchor{1c8}@anchor{gnat_ugn/tools_supporting_project_files project-files-and-main-subprograms}@anchor{e2} +@subsection Project Files and Main Subprograms + + +When using a project file, you can invoke @emph{gnatmake} +with one or several main subprograms, by specifying their source files on the +command line. + +@quotation + +@example +$ gnatmake -Pprj main1.adb main2.adb main3.adb +@end example +@end quotation + +Each of these needs to be a source file of the same project, except +when the switch @cite{-u} is used. + +When @cite{-u} is not used, all the mains need to be sources of the +same project, one of the project in the tree rooted at the project specified +on the command line. The package @cite{Builder} of this common project, the +"main project" is the one that is considered by @emph{gnatmake}. + +When @cite{-u} is used, the specified source files may be in projects +imported directly or indirectly by the project specified on the command line. +Note that if such a source file is not part of the project specified on the +command line, the switches found in package @cite{Builder} of the +project specified on the command line, if any, that are transmitted +to the compiler will still be used, not those found in the project file of +the source file. + +When using a project file, you can also invoke @emph{gnatmake} without +explicitly specifying any main, and the effect depends on whether you have +defined the @cite{Main} attribute. This attribute has a string list value, +where each element in the list is the name of a source file (the file +extension is optional) that contains a unit that can be a main subprogram. + +If the @cite{Main} attribute is defined in a project file as a non-empty +string list and the switch @emph{-u} is not used on the command +line, then invoking @emph{gnatmake} with this project file but without any +main on the command line is equivalent to invoking @emph{gnatmake} with all +the file names in the @cite{Main} attribute on the command line. + +Example: + +@quotation + +@example +project Prj is + for Main use ("main1.adb", "main2.adb", "main3.adb"); +end Prj; +@end example +@end quotation + +With this project file, @cite{"gnatmake -Pprj"} +is equivalent to +@cite{"gnatmake -Pprj main1.adb main2.adb main3.adb"}. + +When the project attribute @cite{Main} is not specified, or is specified +as an empty string list, or when the switch @emph{-u} is used on the command +line, then invoking @emph{gnatmake} with no main on the command line will +result in all immediate sources of the project file being checked, and +potentially recompiled. Depending on the presence of the switch @emph{-u}, +sources from other project files on which the immediate sources of the main +project file depend are also checked and potentially recompiled. In other +words, the @emph{-u} switch is applied to all of the immediate sources of the +main project file. + +When no main is specified on the command line and attribute @cite{Main} exists +and includes several mains, or when several mains are specified on the +command line, the default switches in package @cite{Builder} will +be used for all mains, even if there are specific switches +specified for one or several mains. + +But the switches from package @cite{Binder} or @cite{Linker} will be +the specific switches for each main, if they are specified. + +@node Library Project Files,,Project Files and Main Subprograms,gnatmake and Project Files +@anchor{gnat_ugn/tools_supporting_project_files id7}@anchor{1c9}@anchor{gnat_ugn/tools_supporting_project_files library-project-files}@anchor{1ca} +@subsection Library Project Files + + +When @emph{gnatmake} is invoked with a main project file that is a library +project file, it is not allowed to specify one or more mains on the command +line. + +When a library project file is specified, switches @cite{-b} and +@cite{-l} have special meanings. + + +@itemize * + +@item +@cite{-b} is only allowed for stand-alone libraries. It indicates +to @emph{gnatmake} that @emph{gnatbind} should be invoked for the +library. + +@item +@cite{-l} may be used for all library projects. It indicates +to @emph{gnatmake} that the binder generated file should be compiled +(in the case of a stand-alone library) and that the library should be built. @end itemize -@item All types -This metric is computed for any compilation unit. It is equal to the total -number of the declarations of different types given in the compilation unit. -The private and the corresponding full type declaration are counted as one -type declaration. Incomplete type declarations and generic formal types -are not counted. -No distinction is made among different kinds of types (abstract, -private etc.); the total number of types is computed and reported. +@node The GNAT Driver and Project Files,,gnatmake and Project Files,Tools Supporting Project Files +@anchor{gnat_ugn/tools_supporting_project_files id8}@anchor{1cb}@anchor{gnat_ugn/tools_supporting_project_files the-gnat-driver-and-project-files}@anchor{11f} +@section The GNAT Driver and Project Files -@end table -@noindent -By default, all the syntax metrics are computed and reported. You can use the -following switches to select specific syntax metrics. +A number of GNAT tools beyond @emph{gnatmake} +can benefit from project files: -@table @option -@cindex @option{--syntax@var{x}} (@command{gnatmetric}) -@cindex @option{--no-syntax@var{x}} (@command{gnatmetric}) +@itemize * -@item --syntax-all -Report all the syntax metrics +@item +@emph{gnatbind} -@item --no-syntax-all -Do not report any of syntax metrics +@item +@emph{gnatclean} -@item --declarations -Report the total number of declarations +@item +@emph{gnatfind} -@item --no-declarations -Do not report the total number of declarations +@item +@emph{gnatlink} -@item --statements -Report the total number of statements +@item +@emph{gnatls} -@item --no-statements -Do not report the total number of statements +@item +@emph{gnatxref} +@end itemize -@item --public-subprograms -Report the number of public subprograms in a compilation unit +However, none of these tools can be invoked +directly with a project file switch (@emph{-P}). +They must be invoked through the @emph{gnat} driver. -@item --no-public-subprograms -Do not report the number of public subprograms in a compilation unit +The @emph{gnat} driver is a wrapper that accepts a number of commands and +calls the corresponding tool. It was designed initially for VMS platforms (to +convert VMS qualifiers to Unix-style switches), but it is now available on all +GNAT platforms. -@item --all-subprograms -Report the number of all the subprograms in a compilation unit +On non-VMS platforms, the @emph{gnat} driver accepts the following commands +(case insensitive): -@item --no-all-subprograms -Do not report the number of all the subprograms in a compilation unit -@item --public-types -Report the number of public types in a compilation unit -@item --no-public-types -Do not report the number of public types in a compilation unit +@itemize * -@item --all-types -Report the number of all the types in a compilation unit +@item +BIND to invoke @emph{gnatbind} -@item --no-all-types -Do not report the number of all the types in a compilation unit +@item +CHOP to invoke @emph{gnatchop} -@item --unit-nesting -Report the maximal program unit nesting level +@item +CLEAN to invoke @emph{gnatclean} -@item --no-unit-nesting -Do not report the maximal program unit nesting level +@item +COMP or COMPILE to invoke the compiler -@item --construct-nesting -Report the maximal construct nesting level +@item +FIND to invoke @emph{gnatfind} -@item --no-construct-nesting -Do not report the maximal construct nesting level +@item +KR or KRUNCH to invoke @emph{gnatkr} -@end table +@item +LINK to invoke @emph{gnatlink} -@node Complexity Metrics Control -@subsubsection Complexity Metrics Control -@cindex Complexity metrics control in @command{gnatmetric} +@item +LS or LIST to invoke @emph{gnatls} -@noindent -For a program unit that is an executable body (a subprogram body (including -generic bodies), task body, entry body or a package body containing -its own statement sequence) @command{gnatmetric} computes the following -complexity metrics: +@item +MAKE to invoke @emph{gnatmake} -@itemize @bullet -@item -McCabe cyclomatic complexity; +@item +NAME to invoke @emph{gnatname} -@item -McCabe essential complexity; +@item +PREP or PREPROCESS to invoke @emph{gnatprep} -@item -maximal loop nesting level; +@item +XREF to invoke @emph{gnatxref} +@end itemize -@item -extra exit points (for subprograms); +Note that the command +@emph{gnatmake -c -f -u} is used to invoke the compiler. + +On non-VMS platforms, between @emph{gnat} and the command, two +special switches may be used: + + +@itemize * + +@item +@emph{-v} to display the invocation of the tool. + +@item +@emph{-dn} to prevent the @emph{gnat} driver from removing +the temporary files it has created. These temporary files are +configuration files and temporary file list files. @end itemize -@noindent -The McCabe cyclomatic complexity metric is defined -in @url{http://www.mccabe.com/pdf/mccabe-nist235r.pdf} +The command may be followed by switches and arguments for the invoked +tool. -According to McCabe, both control statements and short-circuit control forms -should be taken into account when computing cyclomatic complexity. -For Ada 2012 we have also take into account conditional expressions -and quantified expressions. For each body, we compute three metric values: +@quotation -@itemize @bullet -@item -the complexity introduced by control -statements only, without taking into account short-circuit forms -(referred as @code{statement complexity} in @command{gnatmetric} output), +@example +$ gnat bind -C main.ali +$ gnat ls -a main +$ gnat chop foo.txt +@end example +@end quotation -@item -the complexity introduced by short-circuit control forms only -(referred as @code{expression complexity} in @command{gnatmetric} output), and +Switches may also be put in text files, one switch per line, and the text +files may be specified with their path name preceded by '@@'. -@item -the total -cyclomatic complexity, which is the sum of these two values -(referred as @code{cyclomatic complexity} in @command{gnatmetric} output). +@quotation + +@example +$ gnat bind @@args.txt main.ali +@end example +@end quotation + +In addition, for the following commands the project file related switches +(@emph{-P}, @emph{-X} and @emph{-vPx}) may be used in addition to +the switches of the invoking tool: + + + +@itemize * + +@item +BIND + +@item +COMP or COMPILE + +@item +FIND + +@item +LS or LIST + +@item +LINK + +@item +XREF @end itemize -@noindent - -The cyclomatic complexity is also computed for Ada 2012 expression functions. -An expression function cannot have statements as its components, so only one -metric value is computed as a cyclomatic complexity of an expression function. - -The origin of cyclomatic complexity metric is the need to estimate the number -of independent paths in the control flow graph that in turn gives the number -of tests needed to satisfy paths coverage testing completeness criterion. -Considered from the testing point of view, a static Ada @code{loop} (that is, -the @code{loop} statement having static subtype in loop parameter -specification) does not add to cyclomatic complexity. By providing -@option{--no-static-loop} option a user -may specify that such loops should not be counted when computing the -cyclomatic complexity metric - -The Ada essential complexity metric is a McCabe cyclomatic complexity metric -counted for the code that is reduced by excluding all the pure structural Ada -control statements. An compound statement is considered as a non-structural -if it contains a @code{raise} or @code{return} statement as it subcomponent, -or if it contains a @code{goto} statement that transfers the control outside -the operator. A selective accept statement with @code{terminate} alternative -is considered as non-structural statement. When computing this metric, -@code{exit} statements are treated in the same way as @code{goto} -statements unless @option{-ne} option is specified. - -The Ada essential complexity metric defined here is intended to quantify -the extent to which the software is unstructured. It is adapted from -the McCabe essential complexity metric defined in -@url{http://www.mccabe.com/pdf/mccabe-nist235r.pdf} but is modified to be more -suitable for typical Ada usage. For example, short circuit forms -are not penalized as unstructured in the Ada essential complexity metric. - -When computing cyclomatic and essential complexity, @command{gnatmetric} skips -the code in the exception handlers and in all the nested program units. The -code of assertions and predicates (that is, subprogram preconditions and -postconditions, subtype predicates and type invariants) is also skipped. - -By default, all the complexity metrics are computed and reported. -For more fine-grained control you can use -the following switches: - -@table @option -@cindex @option{-complexity@var{x}} (@command{gnatmetric}) - -@cindex @option{--no-complexity@var{x}} - -@item --complexity-all -Report all the complexity metrics - -@item --no-complexity-all -Do not report any of complexity metrics - -@item --complexity-cyclomatic -Report the McCabe Cyclomatic Complexity - -@item --no-complexity-cyclomatic -Do not report the McCabe Cyclomatic Complexity - -@item --complexity-essential -Report the Essential Complexity - -@item --no-complexity-essential -Do not report the Essential Complexity - -@item --loop-nesting -Report maximal loop nesting level - -@item --no-loop-nesting -Do not report maximal loop nesting level - -@item --complexity-average -Report the average McCabe Cyclomatic Complexity for all the subprogram bodies, -task bodies, entry bodies and statement sequences in package bodies. -The metric is computed and reported for whole set of processed Ada sources -only. -@item --no-complexity-average -Do not report the average McCabe Cyclomatic Complexity for all the subprogram -bodies, task bodies, entry bodies and statement sequences in package bodies +For each of the following commands, there is optionally a corresponding +package in the main project. -@cindex @option{-ne} (@command{gnatmetric}) -@item -ne -Do not consider @code{exit} statements as @code{goto}s when -computing Essential Complexity -@cindex @option{--no-static-loop} (@command{gnatmetric}) -@item --no-static-loop -Do not consider static loops when computing cyclomatic complexity -@item --extra-exit-points -Report the extra exit points for subprogram bodies. As an exit point, this -metric counts @code{return} statements and raise statements in case when the -raised exception is not handled in the same body. In case of a function this -metric subtracts 1 from the number of exit points, because a function body -must contain at least one @code{return} statement. +@itemize * -@item --no-extra-exit-points -Do not report the extra exit points for subprogram bodies -@end table +@item +package @cite{Binder} for command BIND (invoking @cite{gnatbind}) +@item +package @cite{Compiler} for command COMP or COMPILE (invoking the compiler) -@node Coupling Metrics Control -@subsubsection Coupling Metrics Control -@cindex Coupling metrics control in @command{gnatmetric} +@item +package @cite{Cross_Reference} for command XREF (invoking @cite{gnatxref}) -@noindent -@cindex Coupling metrics (in @command{gnatmetric}) -Coupling metrics measure the dependencies between a given entity and other -entities in the program. This information is useful since high coupling -may signal potential issues with maintainability as the program evolves. +@item +package @cite{Finder} for command FIND (invoking @cite{gnatfind}) -@command{gnatmetric} computes the following coupling metrics: +@item +package @cite{Gnatls} for command LS or LIST (invoking @cite{gnatls}) -@itemize @bullet +@item +package @cite{Linker} for command LINK (invoking @cite{gnatlink}) +@end itemize -@item -@emph{object-oriented coupling}, for classes in traditional object-oriented -sense; +Package @cite{Gnatls} has a unique attribute @cite{Switches}, +a simple variable with a string list value. It contains switches +for the invocation of @cite{gnatls}. -@item -@emph{unit coupling}, for all the program units making up a program; +@quotation -@item -@emph{control coupling}, reflecting dependencies between a unit and -other units that contain subprograms. +@example +project Proj1 is + package gnatls is + for Switches + use ("-a", + "-v"); + end gnatls; +end Proj1; +@end example +@end quotation + +All other packages have two attribute @cite{Switches} and +@cite{Default_Switches}. + +@cite{Switches} is an indexed attribute, indexed by the +source file name, that has a string list value: the switches to be +used when the tool corresponding to the package is invoked for the specific +source file. + +@cite{Default_Switches} is an attribute, +indexed by the programming language that has a string list value. +@cite{Default_Switches ("Ada")} contains the +switches for the invocation of the tool corresponding +to the package, except if a specific @cite{Switches} attribute +is specified for the source file. + +@quotation + +@example +project Proj is + + for Source_Dirs use (""); + + package gnatls is + for Switches use + ("-a", + "-v"); + end gnatls; + + package Compiler is + for Default_Switches ("Ada") + use ("-gnatv", + "-gnatwa"); + end Binder; + + package Binder is + for Default_Switches ("Ada") + use ("-C", + "-e"); + end Binder; + + package Linker is + for Default_Switches ("Ada") + use ("-C"); + for Switches ("main.adb") + use ("-C", + "-v", + "-v"); + end Linker; + + package Finder is + for Default_Switches ("Ada") + use ("-a", + "-f"); + end Finder; + + package Cross_Reference is + for Default_Switches ("Ada") + use ("-a", + "-f", + "-d", + "-u"); + end Cross_Reference; +end Proj; +@end example +@end quotation + +With the above project file, commands such as + +@quotation + +@example +$ gnat comp -Pproj main +$ gnat ls -Pproj main +$ gnat xref -Pproj main +$ gnat bind -Pproj main.ali +$ gnat link -Pproj main.ali +@end example +@end quotation + +will set up the environment properly and invoke the tool with the switches +found in the package corresponding to the tool: +@cite{Default_Switches ("Ada")} for all tools, +except @cite{Switches ("main.adb")} +for @cite{gnatlink}. + + +@node GNAT Utility Programs,GNAT and Program Execution,Tools Supporting Project Files,Top +@anchor{gnat_ugn/gnat_utility_programs doc}@anchor{1cc}@anchor{gnat_ugn/gnat_utility_programs gnat-utility-programs}@anchor{d}@anchor{gnat_ugn/gnat_utility_programs id1}@anchor{1cd} +@chapter GNAT Utility Programs + + +This chapter describes a number of utility programs: + + + +@itemize * + +@item +@ref{22,,The File Cleanup Utility gnatclean} + +@item +@ref{23,,The GNAT Library Browser gnatls} + +@item +@ref{24,,The Cross-Referencing Tools gnatxref and gnatfind} + +@item +@ref{25,,The Ada to HTML Converter gnathtml} @end itemize -@noindent -Two kinds of coupling metrics are computed: - -@itemize @bullet -@item fan-out coupling (``efferent coupling''): -@cindex fan-out coupling -@cindex efferent coupling -the number of entities the given entity depends upon. This metric -reflects how the given entity depends on the changes in the -``external world''. - -@item fan-in coupling (``afferent'' coupling): -@cindex fan-in coupling -@cindex afferent coupling -the number of entities that depend on a given entity. -This metric reflects how the ``external world'' depends on the changes in a -given entity. +Other GNAT utilities are described elsewhere in this manual: + + +@itemize * + +@item +@ref{5b,,Handling Arbitrary File Naming Conventions with gnatname} + +@item +@ref{65,,File Name Krunching with gnatkr} + +@item +@ref{38,,Renaming Files with gnatchop} + +@item +@ref{19,,Preprocessing with gnatprep} @end itemize -@noindent -Object-oriented coupling metrics measure the dependencies -between a given class (or a group of classes) and the other classes in the -program. In this subsection the term ``class'' is used in its traditional -object-oriented programming sense (an instantiable module that contains data -and/or method members). A @emph{category} (of classes) is a group of closely -related classes that are reused and/or modified together. - -A class @code{K}'s fan-out coupling is the number of classes -that @code{K} depends upon. -A category's fan-out coupling is the number of classes outside the -category that the classes inside the category depend upon. - -A class @code{K}'s fan-in coupling is the number of classes -that depend upon @code{K}. -A category's fan-in coupling is the number of classes outside the -category that depend on classes belonging to the category. - -Ada's object-oriented paradigm separates the instantiable entity -(type) from the module (package), so the definition of the coupling -metrics for Ada maps the class and class category notions -onto Ada constructs. - -For the coupling metrics, several kinds of modules that define a tagged type -or an interface type -- library packages, library generic packages, and -library generic package instantiations -- are considered to be classes. -A category consists of a library package (or -a library generic package) that defines a tagged or an interface type, -together with all its descendant (generic) packages that define tagged -or interface types. Thus a -category is an Ada hierarchy of library-level program units. Class -coupling in Ada is referred to as ``tagged coupling'', and category coupling -is referred to as ``hierarchy coupling''. - -For any package serving as a class, its body and subunits (if any) are -considered together with its spec when computing dependencies, and coupling -metrics are reported for spec units only. Dependencies between classes -mean Ada semantic dependencies. For object-oriented coupling -metrics, only dependencies on units treated as classes are -considered. - -Similarly, for unit and control coupling an entity is considered to be the -conceptual construct consisting of the entity's specification, body, and -any subunits (transitively). -@command{gnatmetric} computes -the dependencies of all these units as a whole, but -metrics are only reported for spec -units (or for a subprogram body unit in case if there is no -separate spec for the given subprogram). - -For unit coupling, dependencies are computed between all kinds of program -units. For control coupling, the dependencies of a given unit are limited to -those units that define subprograms. Thus control fan-out coupling is reported -for all units, but control fan-in coupling is only reported for units -that define subprograms. - -The following simple example illustrates the difference between unit coupling -and control coupling metrics: - -@smallexample @c ada -@group -@b{package} Lib_1 @b{is} - @b{function} F_1 (I : Integer) @b{return} Integer; -@b{end} Lib_1; -@end group - -@group -@b{package} Lib_2 @b{is} - @b{type} T_2 @b{is} @b{new} Integer; -@b{end} Lib_2; -@end group - -@group -@b{package} @b{body} Lib_1 @b{is} - @b{function} F_1 (I : Integer) @b{return} Integer @b{is} - @b{begin} - @b{return} I + 1; - @b{end} F_1; -@b{end} Lib_1; -@end group - -@group -@b{with} Lib_2; @b{use} Lib_2; -@b{package} Pack @b{is} - Var : T_2; - @b{function} Fun (I : Integer) @b{return} Integer; -@b{end} Pack; -@end group - -@group -@b{with} Lib_1; @b{use} Lib_1; -@b{package} @b{body} Pack @b{is} - @b{function} Fun (I : Integer) @b{return} Integer @b{is} - @b{begin} - @b{return} F_1 (I); - @b{end} Fun; -@b{end} Pack; -@end group -@end smallexample - -@noindent -If we apply @command{gnatmetric} with the @option{--coupling-all} option to -these units, the result will be: - -@smallexample -@group -Coupling metrics: -================= - Unit Lib_1 (C:\customers\662\L406-007\lib_1.ads) - control fan-out coupling : 0 - control fan-in coupling : 1 - unit fan-out coupling : 0 - unit fan-in coupling : 1 -@end group - -@group - Unit Pack (C:\customers\662\L406-007\pack.ads) - control fan-out coupling : 1 - control fan-in coupling : 0 - unit fan-out coupling : 2 - unit fan-in coupling : 0 -@end group - -@group - Unit Lib_2 (C:\customers\662\L406-007\lib_2.ads) - control fan-out coupling : 0 - unit fan-out coupling : 0 - unit fan-in coupling : 1 -@end group -@end smallexample - -@noindent -The result does not contain values for object-oriented -coupling because none of the argument units contains a tagged type and -therefore none of these units can be treated as a class. - -The @code{Pack} package (spec and body) depends on two -units -- @code{Lib_1} @code{and Lib_2} -- and so its unit fan-out coupling -is 2. Since nothing depends on it, its unit fan-in coupling is 0, as -is its control fan-in coupling. Only one of the units @code{Pack} depends -upon defines a subprogram, so its control fan-out coupling is 1. - -@code{Lib_2} depends on nothing, so its fan-out metrics are 0. It does -not define any subprograms, so it has no control fan-in metric. -One unit (@code{Pack}) depends on it , so its unit fan-in coupling is 1. - -@code{Lib_1} is similar to @code{Lib_2}, but it does define a subprogram. -Its control fan-in coupling is 1 (because there is one unit -depending on it). - -When computing coupling metrics, @command{gnatmetric} counts only -dependencies between units that are arguments of the @command{gnatmetric} -invocation. Coupling metrics are program-wide (or project-wide) metrics, so -you should invoke @command{gnatmetric} for -the complete set of sources comprising your program. This can be done -by invoking @command{gnatmetric} with the corresponding project file -and with the @option{-U} option. - -By default, all the coupling metrics are disabled. You can use the following -switches to specify the coupling metrics to be computed and reported: - -@table @option - -@cindex @option{--tagged-coupling@var{x}} (@command{gnatmetric}) -@cindex @option{--hierarchy-coupling@var{x}} (@command{gnatmetric}) -@cindex @option{--unit-coupling@var{x}} (@command{gnatmetric}) -@cindex @option{--control-coupling@var{x}} (@command{gnatmetric}) - - -@item --coupling-all -Report all the coupling metrics - -@item --tagged-coupling-out -Report tagged (class) fan-out coupling - -@item --tagged-coupling-in -Report tagged (class) fan-in coupling - -@item --hierarchy-coupling-out -Report hierarchy (category) fan-out coupling - -@item --hierarchy-coupling-in -Report hierarchy (category) fan-in coupling - -@item --unit-coupling-out -Report unit fan-out coupling - -@item --unit-coupling-in -Report unit fan-in coupling - -@item --control-coupling-out -Report control fan-out coupling - -@item --control-coupling-in -Report control fan-in coupling -@end table - -@node Other gnatmetric Switches -@subsection Other @code{gnatmetric} Switches +@menu +* The File Cleanup Utility gnatclean:: +* The GNAT Library Browser gnatls:: +* The Cross-Referencing Tools gnatxref and gnatfind:: +* The Ada to HTML Converter gnathtml:: -@noindent -Additional @command{gnatmetric} switches are as follows: - -@table @option -@item --version -@cindex @option{--version} @command{gnatmetric} -Display Copyright and version, then exit disregarding all other options. +@end menu + +@node The File Cleanup Utility gnatclean,The GNAT Library Browser gnatls,,GNAT Utility Programs +@anchor{gnat_ugn/gnat_utility_programs id2}@anchor{1ce}@anchor{gnat_ugn/gnat_utility_programs the-file-cleanup-utility-gnatclean}@anchor{22} +@section The File Cleanup Utility @emph{gnatclean} + + +@geindex File cleanup tool + +@geindex gnatclean + +@cite{gnatclean} is a tool that allows the deletion of files produced by the +compiler, binder and linker, including ALI files, object files, tree files, +expanded source files, library files, interface copy source files, binder +generated files and executable files. -@item --help -@cindex @option{--help} @command{gnatmetric} -Display usage, then exit disregarding all other options. - -@item -P @var{file} -@cindex @option{-P} @command{gnatmetric} -Indicates the name of the project file that describes the set of sources -to be processed. The exact set of argument sources depends on other options -specified, see below. - -@item -U -@cindex @option{-U} @command{gnatmetric} -If a project file is specified and no argument source is explicitly -specified (either directly or by means of @option{-files} option), process -all the units of the closure of the argument project. Otherwise this option -has no effect. - -@item -U @var{main_unit} -If a project file is specified and no argument source is explicitly -specified (either directly or by means of @option{-files} option), process -the closure of units rooted at @var{main_unit}. Otherwise this option -has no effect. - -@item -X@var{name}=@var{value} -@cindex @option{-X} @command{gnatmetric} -Indicates that external variable @var{name} in the argument project -has the value @var{value}. Has no effect if no project is specified as -tool argument. - -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gnatmetric}) -Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). - -@item --subdirs=@var{dir} -@cindex @option{--subdirs=@var{dir}} @command{gnatmetric} -Use the specified subdirectory of the project objects file (or of the -project file directory if the project does not specify an object directory) -for tool output files. Has no effect if no project is specified as -tool argument r if @option{--no_objects_dir} is specified. - -@item --no_objects_dir -@cindex @option{--no_objects_dir} @command{gnatmetric} -Place all the result files into the current directory instead of -project objects directory. This corresponds to the @command{gnatcheck} -behavior when it is called with the project file from the -GNAT driver. Has no effect if no project is specified. - -@item -files @var{filename} -@cindex @option{-files} (@code{gnatmetric}) -Take the argument source files from the specified file. This file should be an -ordinary text file containing file names separated by spaces or -line breaks. You can use this switch more than once in the same call to -@command{gnatmetric}. You also can combine this switch with -an explicit list of files. - -@item -j@var{n} -@cindex @option{-j} (@command{gnatmetric}) -Use @var{n} processes to carry out the tree creations (internal representations -of the argument sources). On a multiprocessor machine this speeds up processing -of big sets of argument sources. If @var{n} is 0, then the maximum number of -parallel tree creations is the number of core processors on the platform. - -@cindex @option{-t} (@command{gnatmetric}) -@item -t -Print out execution time. - -@item -v -@cindex @option{-v} (@command{gnatmetric}) -Verbose mode; -@command{gnatmetric} generates version information and then -a trace of sources being processed. - -@item -q -@cindex @option{-q} (@command{gnatmetric}) -Quiet mode. -@end table - -@noindent -If a project file is specified and no argument source is explicitly -specified (either directly or by means of @option{-files} option), and no -@option{-U} is specified, then the set of processed sources is -all the immediate units of the argument project. - - -@ignore -@node Generate project-wide metrics -@subsection Generate project-wide metrics - -In order to compute metrics on all units of a given project, you can use -the @command{gnat} driver along with the @option{-P} option: -@smallexample - gnat metric -Pproj -@end smallexample - -@noindent -If the project @code{proj} depends upon other projects, you can compute -the metrics on the project closure using the @option{-U} option: -@smallexample - gnat metric -Pproj -U -@end smallexample - -@noindent -Finally, if not all the units are relevant to a particular main -program in the project closure, you can generate metrics for the set -of units needed to create a given main program (unit closure) using -the @option{-U} option followed by the name of the main unit: -@smallexample - gnat metric -Pproj -U main -@end smallexample -@end ignore -@end ifclear - - -@c *********************************** -@node File Name Krunching with gnatkr -@chapter File Name Krunching with @code{gnatkr} -@findex gnatkr - -@noindent -This chapter discusses the method used by the compiler to shorten -the default file names chosen for Ada units so that they do not -exceed the maximum length permitted. It also describes the -@code{gnatkr} utility that can be used to determine the result of -applying this shortening. @menu -* About gnatkr:: -* Using gnatkr:: -* Krunching Method:: -* Examples of gnatkr Usage:: +* Running gnatclean:: +* Switches for gnatclean:: + @end menu -@node About gnatkr -@section About @code{gnatkr} +@node Running gnatclean,Switches for gnatclean,,The File Cleanup Utility gnatclean +@anchor{gnat_ugn/gnat_utility_programs running-gnatclean}@anchor{1cf}@anchor{gnat_ugn/gnat_utility_programs id3}@anchor{1d0} +@subsection Running @cite{gnatclean} -@noindent -The default file naming rule in GNAT -is that the file name must be derived from -the unit name. The exact default rule is as follows: -@itemize @bullet -@item -Take the unit name and replace all dots by hyphens. -@item -If such a replacement occurs in the -second character position of a name, and the first character is -@samp{a}, @samp{g}, @samp{s}, or @samp{i}, -then replace the dot by the character -@samp{~} (tilde) -instead of a minus. -@end itemize -The reason for this exception is to avoid clashes -with the standard names for children of System, Ada, Interfaces, -and GNAT, which use the prefixes -@samp{s-}, @samp{a-}, @samp{i-}, and @samp{g-}, -respectively. -The @option{-gnatk@var{nn}} -switch of the compiler activates a ``krunching'' -circuit that limits file names to nn characters (where nn is a decimal -integer). For example, using OpenVMS, -where the maximum file name length is -39, the value of nn is usually set to 39, but if you want to generate -a set of files that would be usable if ported to a system with some -different maximum file length, then a different value can be specified. -The default value of 39 for OpenVMS need not be specified. - -The @code{gnatkr} utility can be used to determine the krunched name for -a given file, when krunched to a specified maximum length. +The @cite{gnatclean} command has the form: -@node Using gnatkr -@section Using @code{gnatkr} +@quotation -@noindent -The @code{gnatkr} command has the form +@example +$ gnatclean switches `names` +@end example +@end quotation -@smallexample -@c $ gnatkr @var{name} @ovar{length} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatkr @var{name} @r{[}@var{length}@r{]} -@end smallexample +where @cite{names} is a list of source file names. Suffixes @code{.ads} and +@code{adb} may be omitted. If a project file is specified using switch +@code{-P}, then @cite{names} may be completely omitted. +In normal mode, @cite{gnatclean} delete the files produced by the compiler and, +if switch @cite{-c} is not specified, by the binder and +the linker. In informative-only mode, specified by switch +@cite{-n}, the list of files that would have been deleted in +normal mode is listed, but no file is actually deleted. -@noindent -@var{name} is the uncrunched file name, derived from the name of the unit -in the standard manner described in the previous section (i.e., in particular -all dots are replaced by hyphens). The file name may or may not have an -extension (defined as a suffix of the form period followed by arbitrary -characters other than period). If an extension is present then it will -be preserved in the output. For example, when krunching @file{hellofile.ads} -to eight characters, the result will be hellofil.ads. +@node Switches for gnatclean,,Running gnatclean,The File Cleanup Utility gnatclean +@anchor{gnat_ugn/gnat_utility_programs id4}@anchor{1d1}@anchor{gnat_ugn/gnat_utility_programs switches-for-gnatclean}@anchor{1d2} +@subsection Switches for @cite{gnatclean} -Note: for compatibility with previous versions of @code{gnatkr} dots may -appear in the name instead of hyphens, but the last dot will always be -taken as the start of an extension. So if @code{gnatkr} is given an argument -such as @file{Hello.World.adb} it will be treated exactly as if the first -period had been a hyphen, and for example krunching to eight characters -gives the result @file{hellworl.adb}. -Note that the result is always all lower case (except on OpenVMS where it is -all upper case). Characters of the other case are folded as required. +@cite{gnatclean} recognizes the following switches: -@var{length} represents the length of the krunched name. The default -when no argument is given is 8 characters. A length of zero stands for -unlimited, in other words do not chop except for system files where the -implied crunching length is always eight characters. +@geindex --version (gnatclean) -@noindent -The output is the krunched name. The output has an extension only if the -original argument was a file name with an extension. -@node Krunching Method -@section Krunching Method +@table @asis -@noindent -The initial file name is determined by the name of the unit that the file -contains. The name is formed by taking the full expanded name of the -unit and replacing the separating dots with hyphens and -using lowercase -for all letters, except that a hyphen in the second character position is -replaced by a tilde if the first character is -@samp{a}, @samp{i}, @samp{g}, or @samp{s}. -The extension is @code{.ads} for a -spec and @code{.adb} for a body. -Krunching does not affect the extension, but the file name is shortened to -the specified length by following these rules: +@item @code{--version} -@itemize @bullet -@item -The name is divided into segments separated by hyphens, tildes or -underscores and all hyphens, tildes, and underscores are -eliminated. If this leaves the name short enough, we are done. +Display Copyright and version, then exit disregarding all other options. +@end table -@item -If the name is too long, the longest segment is located (left-most -if there are two of equal length), and shortened by dropping -its last character. This is repeated until the name is short enough. +@geindex --help (gnatclean) -As an example, consider the krunching of @*@file{our-strings-wide_fixed.adb} -to fit the name into 8 characters as required by some operating systems. -@smallexample -our-strings-wide_fixed 22 -our strings wide fixed 19 -our string wide fixed 18 -our strin wide fixed 17 -our stri wide fixed 16 -our stri wide fixe 15 -our str wide fixe 14 -our str wid fixe 13 -our str wid fix 12 -ou str wid fix 11 -ou st wid fix 10 -ou st wi fix 9 -ou st wi fi 8 -Final file name: oustwifi.adb -@end smallexample +@table @asis -@item -The file names for all predefined units are always krunched to eight -characters. The krunching of these predefined units uses the following -special prefix replacements: +@item @code{--help} -@table @file -@item ada- -replaced by @file{a-} +If @emph{--version} was not used, display usage, then exit disregarding +all other options. + +@item @code{--subdirs=@emph{subdir}} -@item gnat- -replaced by @file{g-} +Actual object directory of each project file is the subdirectory subdir of the +object directory specified or defaulted in the project file. -@item interfaces- -replaced by @file{i-} +@item @code{--unchecked-shared-lib-imports} -@item system- -replaced by @file{s-} +By default, shared library projects are not allowed to import static library +projects. When this switch is used on the command line, this restriction is +relaxed. @end table -These system files have a hyphen in the second character position. That -is why normal user files replace such a character with a -tilde, to -avoid confusion with system file names. +@geindex -c (gnatclean) -As an example of this special rule, consider -@*@file{ada-strings-wide_fixed.adb}, which gets krunched as follows: -@smallexample -ada-strings-wide_fixed 22 -a- strings wide fixed 18 -a- string wide fixed 17 -a- strin wide fixed 16 -a- stri wide fixed 15 -a- stri wide fixe 14 -a- str wide fixe 13 -a- str wid fixe 12 -a- str wid fix 11 -a- st wid fix 10 -a- st wi fix 9 -a- st wi fi 8 -Final file name: a-stwifi.adb -@end smallexample -@end itemize +@table @asis -Of course no file shortening algorithm can guarantee uniqueness over all -possible unit names, and if file name krunching is used then it is your -responsibility to ensure that no name clashes occur. The utility -program @code{gnatkr} is supplied for conveniently determining the -krunched name of a file. +@item @code{-c} -@node Examples of gnatkr Usage -@section Examples of @code{gnatkr} Usage +Only attempt to delete the files produced by the compiler, not those produced +by the binder or the linker. The files that are not to be deleted are library +files, interface copy files, binder generated files and executable files. +@end table -@smallexample -@iftex -@leftskip=0cm -@end iftex -$ gnatkr very_long_unit_name.ads --> velounna.ads -$ gnatkr grandparent-parent-child.ads --> grparchi.ads -$ gnatkr Grandparent.Parent.Child.ads --> grparchi.ads -$ gnatkr grandparent-parent-child --> grparchi -$ gnatkr very_long_unit_name.ads/count=6 --> vlunna.ads -$ gnatkr very_long_unit_name.ads/count=0 --> very_long_unit_name.ads -@end smallexample +@geindex -D (gnatclean) -@node Preprocessing with gnatprep -@chapter Preprocessing with @code{gnatprep} -@findex gnatprep -@noindent -This chapter discusses how to use GNAT's @code{gnatprep} utility for simple -preprocessing. -Although designed for use with GNAT, @code{gnatprep} does not depend on any -special GNAT features. -For further discussion of conditional compilation in general, see -@ref{Conditional Compilation}. +@table @asis -@menu -* Preprocessing Symbols:: -* Using gnatprep:: -* Switches for gnatprep:: -* Form of Definitions File:: -* Form of Input Text for gnatprep:: -@end menu +@item @code{-D @emph{dir}} -@node Preprocessing Symbols -@section Preprocessing Symbols +Indicate that ALI and object files should normally be found in directory @cite{dir}. +@end table -@noindent -Preprocessing symbols are defined in definition files and referred to in -sources to be preprocessed. A Preprocessing symbol is an identifier, following -normal Ada (case-insensitive) rules for its syntax, with the restriction that -all characters need to be in the ASCII set (no accented letters). +@geindex -F (gnatclean) -@node Using gnatprep -@section Using @code{gnatprep} -@noindent -To call @code{gnatprep} use +@table @asis -@smallexample -@c $ gnatprep @ovar{switches} @var{infile} @var{outfile} @ovar{deffile} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatprep @r{[}@var{switches}@r{]} @var{infile} @var{outfile} @r{[}@var{deffile}@r{]} -@end smallexample +@item @code{-F} -@noindent -where -@table @var -@item switches -is an optional sequence of switches as described in the next section. +When using project files, if some errors or warnings are detected during +parsing and verbose mode is not in effect (no use of switch +-v), then error lines start with the full path name of the project +file, rather than its simple file name. +@end table -@item infile -is the full name of the input file, which is an Ada source -file containing preprocessor directives. +@geindex -h (gnatclean) -@item outfile -is the full name of the output file, which is an Ada source -in standard Ada form. When used with GNAT, this file name will -normally have an ads or adb suffix. -@item deffile -is the full name of a text file containing definitions of -preprocessing symbols to be referenced by the preprocessor. This argument is -optional, and can be replaced by the use of the @option{-D} switch. +@table @asis + +@item @code{-h} +Output a message explaining the usage of @cite{gnatclean}. @end table -@node Switches for gnatprep -@section Switches for @code{gnatprep} +@geindex -n (gnatclean) -@table @option -@c !sort! -@item -b -@cindex @option{-b} (@command{gnatprep}) -Causes both preprocessor lines and the lines deleted by -preprocessing to be replaced by blank lines in the output source file, -preserving line numbers in the output file. +@table @asis -@item -c -@cindex @option{-c} (@command{gnatprep}) -Causes both preprocessor lines and the lines deleted -by preprocessing to be retained in the output source as comments marked -with the special string @code{"--! "}. This option will result in line numbers -being preserved in the output file. +@item @code{-n} -@item -C -@cindex @option{-C} (@command{gnatprep}) -Causes comments to be scanned. Normally comments are ignored by gnatprep. -If this option is specified, then comments are scanned and any $symbol -substitutions performed as in program text. This is particularly useful -when structured comments are used (e.g., when writing programs in the -SPARK dialect of Ada). Note that this switch is not available when -doing integrated preprocessing (it would be useless in this context -since comments are ignored by the compiler in any case). +Informative-only mode. Do not delete any files. Output the list of the files +that would have been deleted if this switch was not specified. +@end table -@item -Dsymbol=value -@cindex @option{-D} (@command{gnatprep}) -Defines a new preprocessing symbol, associated with value. If no value is given -on the command line, then symbol is considered to be @code{True}. This switch -can be used in place of a definition file. +@geindex -P (gnatclean) -@item -r -@cindex @option{-r} (@command{gnatprep}) -Causes a @code{Source_Reference} pragma to be generated that -references the original input file, so that error messages will use -the file name of this original file. The use of this switch implies -that preprocessor lines are not to be removed from the file, so its -use will force @option{-b} mode if -@option{-c} -has not been specified explicitly. +@table @asis -Note that if the file to be preprocessed contains multiple units, then -it will be necessary to @code{gnatchop} the output file from -@code{gnatprep}. If a @code{Source_Reference} pragma is present -in the preprocessed file, it will be respected by -@code{gnatchop -r} -so that the final chopped files will correctly refer to the original -input source file for @code{gnatprep}. +@item @code{-P@emph{project}} -@item -s -@cindex @option{-s} (@command{gnatprep}) -Causes a sorted list of symbol names and values to be -listed on the standard output file. +Use project file @cite{project}. Only one such switch can be used. +When cleaning a project file, the files produced by the compilation of the +immediate sources or inherited sources of the project files are to be +deleted. This is not depending on the presence or not of executable names +on the command line. +@end table -@item -u -@cindex @option{-u} (@command{gnatprep}) -Causes undefined symbols to be treated as having the value FALSE in the context -of a preprocessor test. In the absence of this option, an undefined symbol in -a @code{#if} or @code{#elsif} test will be treated as an error. +@geindex -q (gnatclean) + + +@table @asis + +@item @code{-q} +Quiet output. If there are no errors, do not output anything, except in +verbose mode (switch -v) or in informative-only mode +(switch -n). @end table -@noindent -Note: if neither @option{-b} nor @option{-c} is present, -then preprocessor lines and -deleted lines are completely removed from the output, unless -r is -specified, in which case -b is assumed. +@geindex -r (gnatclean) -@node Form of Definitions File -@section Form of Definitions File -@noindent -The definitions file contains lines of the form +@table @asis -@smallexample -symbol := value -@end smallexample +@item @code{-r} -@noindent -where symbol is a preprocessing symbol, and value is one of the following: +When a project file is specified (using switch -P), +clean all imported and extended project files, recursively. If this switch +is not specified, only the files related to the main project file are to be +deleted. This switch has no effect if no project file is specified. +@end table -@itemize @bullet -@item -Empty, corresponding to a null substitution -@item -A string literal using normal Ada syntax -@item -Any sequence of characters from the set -(letters, digits, period, underline). -@end itemize +@geindex -v (gnatclean) -@noindent -Comment lines may also appear in the definitions file, starting with -the usual @code{--}, -and comments may be added to the definitions lines. -@node Form of Input Text for gnatprep -@section Form of Input Text for @code{gnatprep} +@table @asis -@noindent -The input text may contain preprocessor conditional inclusion lines, -as well as general symbol substitution sequences. +@item @code{-v} -The preprocessor conditional inclusion commands have the form +Verbose mode. +@end table -@smallexample -@group -@cartouche -#if @i{expression} @r{[}then@r{]} - lines -#elsif @i{expression} @r{[}then@r{]} - lines -#elsif @i{expression} @r{[}then@r{]} - lines -@dots{} -#else - lines -#end if; -@end cartouche -@end group -@end smallexample - -@noindent -In this example, @i{expression} is defined by the following grammar: -@smallexample -@i{expression} ::= <symbol> -@i{expression} ::= <symbol> = "<value>" -@i{expression} ::= <symbol> = <symbol> -@i{expression} ::= <symbol> = <integer> -@i{expression} ::= <symbol> > <integer> -@i{expression} ::= <symbol> >= <integer> -@i{expression} ::= <symbol> < <integer> -@i{expression} ::= <symbol> <= <integer> -@i{expression} ::= <symbol> 'Defined -@i{expression} ::= not @i{expression} -@i{expression} ::= @i{expression} and @i{expression} -@i{expression} ::= @i{expression} or @i{expression} -@i{expression} ::= @i{expression} and then @i{expression} -@i{expression} ::= @i{expression} or else @i{expression} -@i{expression} ::= ( @i{expression} ) -@end smallexample - -The following restriction exists: it is not allowed to have "and" or "or" -following "not" in the same expression without parentheses. For example, this -is not allowed: +@geindex -vP (gnatclean) -@smallexample - not X or Y -@end smallexample -This should be one of the following: +@table @asis -@smallexample - (not X) or Y - not (X or Y) -@end smallexample +@item @code{-vP@emph{x}} -@noindent -For the first test (@i{expression} ::= <symbol>) the symbol must have -either the value true or false, that is to say the right-hand of the -symbol definition must be one of the (case-insensitive) literals -@code{True} or @code{False}. If the value is true, then the -corresponding lines are included, and if the value is false, they are -excluded. +Indicates the verbosity of the parsing of GNAT project files. +@ref{e3,,Switches Related to Project Files}. +@end table -When comparing a symbol to an integer, the integer is any non negative -literal integer as defined in the Ada Reference Manual, such as 3, 16#FF# or -2#11#. The symbol value must also be a non negative integer. Integer values -in the range 0 .. 2**31-1 are supported. +@geindex -X (gnatclean) -The test (@i{expression} ::= <symbol> @code{'Defined}) is true only if -the symbol has been defined in the definition file or by a @option{-D} -switch on the command line. Otherwise, the test is false. -The equality tests are case insensitive, as are all the preprocessor lines. +@table @asis -If the symbol referenced is not defined in the symbol definitions file, -then the effect depends on whether or not switch @option{-u} -is specified. If so, then the symbol is treated as if it had the value -false and the test fails. If this switch is not specified, then -it is an error to reference an undefined symbol. It is also an error to -reference a symbol that is defined with a value other than @code{True} -or @code{False}. +@item @code{-X@emph{name}=@emph{value}} -The use of the @code{not} operator inverts the sense of this logical test. -The @code{not} operator cannot be combined with the @code{or} or @code{and} -operators, without parentheses. For example, "if not X or Y then" is not -allowed, but "if (not X) or Y then" and "if not (X or Y) then" are. +Indicates that external variable @cite{name} has the value @cite{value}. +The Project Manager will use this value for occurrences of +@cite{external(name)} when parsing the project file. +@ref{e3,,Switches Related to Project Files}. +@end table -The @code{then} keyword is optional as shown +@geindex -aO (gnatclean) -The @code{#} must be the first non-blank character on a line, but -otherwise the format is free form. Spaces or tabs may appear between -the @code{#} and the keyword. The keywords and the symbols are case -insensitive as in normal Ada code. Comments may be used on a -preprocessor line, but other than that, no other tokens may appear on a -preprocessor line. Any number of @code{elsif} clauses can be present, -including none at all. The @code{else} is optional, as in Ada. -The @code{#} marking the start of a preprocessor line must be the first -non-blank character on the line, i.e., it must be preceded only by -spaces or horizontal tabs. +@table @asis -Symbol substitution outside of preprocessor lines is obtained by using -the sequence +@item @code{-aO@emph{dir}} -@smallexample -$symbol -@end smallexample +When searching for ALI and object files, look in directory @cite{dir}. +@end table -@noindent -anywhere within a source line, except in a comment or within a -string literal. The identifier -following the @code{$} must match one of the symbols defined in the symbol -definition file, and the result is to substitute the value of the -symbol in place of @code{$symbol} in the output file. +@geindex -I (gnatclean) -Note that although the substitution of strings within a string literal -is not possible, it is possible to have a symbol whose defined value is -a string literal. So instead of setting XYZ to @code{hello} and writing: -@smallexample -Header : String := "$XYZ"; -@end smallexample +@table @asis -@noindent -you should set XYZ to @code{"hello"} and write: +@item @code{-I@emph{dir}} -@smallexample -Header : String := $XYZ; -@end smallexample +Equivalent to @code{-aO@emph{dir}}. +@end table -@noindent -and then the substitution will occur as desired. +@geindex -I- (gnatclean) + +@geindex Source files +@geindex suppressing search -@node The GNAT Library Browser gnatls -@chapter The GNAT Library Browser @code{gnatls} -@findex gnatls -@cindex Library browser -@noindent -@code{gnatls} is a tool that outputs information about compiled +@table @asis + +@item @code{-I-} + +Do not look for ALI or object files in the directory +where @cite{gnatclean} was invoked. +@end table + +@node The GNAT Library Browser gnatls,The Cross-Referencing Tools gnatxref and gnatfind,The File Cleanup Utility gnatclean,GNAT Utility Programs +@anchor{gnat_ugn/gnat_utility_programs the-gnat-library-browser-gnatls}@anchor{23}@anchor{gnat_ugn/gnat_utility_programs id5}@anchor{1d3} +@section The GNAT Library Browser @cite{gnatls} + + +@geindex Library browser + +@c index: ! gnatls + +@cite{gnatls} is a tool that outputs information about compiled units. It gives the relationship between objects, unit names and source files. It can also be used to check the source dependencies of a unit as well as various characteristics. -Note: to invoke @code{gnatls} with a project file, use the @code{gnat} -driver (see @ref{The GNAT Driver and Project Files}). +Note: to invoke @cite{gnatls} with a project file, use the @cite{gnat} +driver (see @ref{11f,,The GNAT Driver and Project Files}). @menu -* Running gnatls:: -* Switches for gnatls:: -* Examples of gnatls Usage:: +* Running gnatls:: +* Switches for gnatls:: +* Example of gnatls Usage:: + @end menu -@node Running gnatls -@section Running @code{gnatls} +@node Running gnatls,Switches for gnatls,,The GNAT Library Browser gnatls +@anchor{gnat_ugn/gnat_utility_programs id6}@anchor{1d4}@anchor{gnat_ugn/gnat_utility_programs running-gnatls}@anchor{1d5} +@subsection Running @cite{gnatls} + -@noindent -The @code{gnatls} command has the form +The @cite{gnatls} command has the form -@smallexample -$ gnatls switches @var{object_or_ali_file} -@end smallexample +@quotation -@noindent -The main argument is the list of object or @file{ali} files -(@pxref{The Ada Library Information Files}) +@example +$ gnatls switches `object_or_ali_file` +@end example +@end quotation + +The main argument is the list of object or @code{ali} files +(see @ref{44,,The Ada Library Information Files}) for which information is requested. -In normal mode, without additional option, @code{gnatls} produces a +In normal mode, without additional option, @cite{gnatls} produces a four-column listing. Each line represents information for a specific object. The first column gives the full path of the object, the second column gives the name of the principal unit in this object, the third @@ -16618,7 +23404,9 @@ column gives the status of the source and the fourth column gives the full path of the source representing this unit. Here is a simple example of use: -@smallexample +@quotation + +@example $ gnatls *.o ./demo1.o demo1 DIF demo1.adb ./demo2.o demo2 OK demo2.adb @@ -16628,156 +23416,241 @@ $ gnatls *.o ./tef.o tef DIF tef.adb ./text_io_example.o text_io_example OK text_io_example.adb ./tgef.o tgef DIF tgef.adb -@end smallexample +@end example +@end quotation -@noindent The first line can be interpreted as follows: the main unit which is contained in -object file @file{demo1.o} is demo1, whose main source is in -@file{demo1.adb}. Furthermore, the version of the source used for the +object file @code{demo1.o} is demo1, whose main source is in +@code{demo1.adb}. Furthermore, the version of the source used for the compilation of demo1 has been modified (DIF). Each source file has a status qualifier which can be: -@table @code -@item OK (unchanged) + +@table @asis + +@item @emph{OK (unchanged)} + The version of the source file used for the compilation of the specified unit corresponds exactly to the actual source file. -@item MOK (slightly modified) +@item @emph{MOK (slightly modified)} + The version of the source file used for the compilation of the specified unit differs from the actual source file but not enough to require recompilation. If you use gnatmake with the qualifier -@option{-m (minimal recompilation)}, a file marked +@emph{-m (minimal recompilation)}, a file marked MOK will not be recompiled. -@item DIF (modified) +@item @emph{DIF (modified)} + No version of the source found on the path corresponds to the source used to build this object. -@item ??? (file not found) +@item @emph{??? (file not found)} + No source file was found for this unit. -@item HID (hidden, unchanged version not first on PATH) +@item @emph{HID (hidden, unchanged version not first on PATH)} + The version of the source that corresponds exactly to the source used for compilation has been found on the path but it is hidden by another version of the same source that has been modified. - @end table -@node Switches for gnatls -@section Switches for @code{gnatls} +@node Switches for gnatls,Example of gnatls Usage,Running gnatls,The GNAT Library Browser gnatls +@anchor{gnat_ugn/gnat_utility_programs id7}@anchor{1d6}@anchor{gnat_ugn/gnat_utility_programs switches-for-gnatls}@anchor{1d7} +@subsection Switches for @cite{gnatls} + + +@cite{gnatls} recognizes the following switches: + +@geindex --version (gnatls) -@noindent -@code{gnatls} recognizes the following switches: -@table @option -@c !sort! -@cindex @option{--version} @command{gnatls} +@table @asis + +@item @code{--version} + Display Copyright and version, then exit disregarding all other options. +@end table + +@geindex --help (gnatls) + + +@table @asis -@item --help -@cindex @option{--help} @command{gnatls} -If @option{--version} was not used, display usage, then exit disregarding +@item @code{*--help} + +If @emph{--version} was not used, display usage, then exit disregarding all other options. +@end table + +@geindex -a (gnatls) + + +@table @asis + +@item @code{-a} -@item -a -@cindex @option{-a} (@code{gnatls}) Consider all units, including those of the predefined Ada library. -Especially useful with @option{-d}. +Especially useful with @emph{-d}. +@end table + +@geindex -d (gnatls) + + +@table @asis + +@item @code{-d} -@item -d -@cindex @option{-d} (@code{gnatls}) List sources from which specified units depend on. +@end table + +@geindex -h (gnatls) + + +@table @asis + +@item @code{-h} -@item -h -@cindex @option{-h} (@code{gnatls}) Output the list of options. +@end table + +@geindex -o (gnatls) + + +@table @asis + +@item @code{-o} -@item -o -@cindex @option{-o} (@code{gnatls}) Only output information about object files. +@end table + +@geindex -s (gnatls) + + +@table @asis + +@item @code{-s} -@item -s -@cindex @option{-s} (@code{gnatls}) Only output information about source files. +@end table + +@geindex -u (gnatls) + + +@table @asis + +@item @code{-u} -@item -u -@cindex @option{-u} (@code{gnatls}) Only output information about compilation units. +@end table + +@geindex -files (gnatls) + -@item -files=@var{file} -@cindex @option{-files} (@code{gnatls}) -Take as arguments the files listed in text file @var{file}. -Text file @var{file} may contain empty lines that are ignored. +@table @asis + +@item @code{-files=@emph{file}} + +Take as arguments the files listed in text file @cite{file}. +Text file @cite{file} may contain empty lines that are ignored. Each nonempty line should contain the name of an existing file. Several such switches may be specified simultaneously. +@end table + +@geindex -aO (gnatls) + +@geindex -aI (gnatls) + +@geindex -I (gnatls) + +@geindex -I- (gnatls) + + +@table @asis + +@item @code{-aO@emph{dir}}, @code{-aI@emph{dir}}, @code{-I@emph{dir}}, @code{-I-}, @code{-nostdinc} + +Source path manipulation. Same meaning as the equivalent @emph{gnatmake} +flags (@ref{df,,Switches for gnatmake}). +@end table + +@geindex -aP (gnatls) + + +@table @asis + +@item @code{-aP@emph{dir}} + +Add @cite{dir} at the beginning of the project search dir. +@end table + +@geindex --RTS (gnatls) + + +@table @asis + +@item @code{--RTS=@emph{rts-path}`} -@item -aO@var{dir} -@itemx -aI@var{dir} -@itemx -I@var{dir} -@itemx -I- -@itemx -nostdinc -@cindex @option{-aO} (@code{gnatls}) -@cindex @option{-aI} (@code{gnatls}) -@cindex @option{-I} (@code{gnatls}) -@cindex @option{-I-} (@code{gnatls}) -Source path manipulation. Same meaning as the equivalent @command{gnatmake} -flags (@pxref{Switches for gnatmake}). - -@item -aP@var{dir} -@cindex @option{-aP} (@code{gnatls}) -Add @var{dir} at the beginning of the project search dir. - -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@code{gnatls}) Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). +equivalent @emph{gnatmake} flag (@ref{df,,Switches for gnatmake}). +@end table + +@geindex -v (gnatls) + + +@table @asis + +@item @code{-v} -@item -v -@cindex @option{-v} (@code{gnatls}) Verbose mode. Output the complete source, object and project paths. Do not use the default column layout but instead use long format giving as much as information possible on each requested units, including special characteristics such as: -@table @code -@item Preelaborable -The unit is preelaborable in the Ada sense. -@item No_Elab_Code -No elaboration code has been produced by the compiler for this unit. +@itemize * -@item Pure -The unit is pure in the Ada sense. +@item +@emph{Preelaborable}: The unit is preelaborable in the Ada sense. -@item Elaborate_Body -The unit contains a pragma Elaborate_Body. +@item +@emph{No_Elab_Code}: No elaboration code has been produced by the compiler for this unit. -@item Remote_Types -The unit contains a pragma Remote_Types. +@item +@emph{Pure}: The unit is pure in the Ada sense. -@item Shared_Passive -The unit contains a pragma Shared_Passive. +@item +@emph{Elaborate_Body}: The unit contains a pragma Elaborate_Body. -@item Predefined -This unit is part of the predefined environment and cannot be modified -by the user. +@item +@emph{Remote_Types}: The unit contains a pragma Remote_Types. -@item Remote_Call_Interface -The unit contains a pragma Remote_Call_Interface. +@item +@emph{Shared_Passive}: The unit contains a pragma Shared_Passive. -@end table +@item +@emph{Predefined}: This unit is part of the predefined environment and cannot be modified +by the user. +@item +@emph{Remote_Call_Interface}: The unit contains a pragma Remote_Call_Interface. +@end itemize @end table -@node Examples of gnatls Usage -@section Example of @code{gnatls} Usage +@node Example of gnatls Usage,,Switches for gnatls,The GNAT Library Browser gnatls +@anchor{gnat_ugn/gnat_utility_programs id8}@anchor{1d8}@anchor{gnat_ugn/gnat_utility_programs example-of-gnatls-usage}@anchor{1d9} +@subsection Example of @cite{gnatls} Usage + -@noindent Example of using the verbose switch. Note how the source and object paths are affected by the -I switch. -@smallexample +@quotation + +@example $ gnatls -v -I.. demo1.o GNATLS 5.03w (20041123-34) @@ -16803,15 +23676,17 @@ Project Search Path: Kind => subprogram body Flags => No_Elab_Code Source => demo1.adb modified -@end smallexample +@end example +@end quotation -@noindent The following is an example of use of the dependency list. Note the use of the -s switch which gives a straight list of source files. This can be useful for building specialized scripts. -@smallexample +@quotation + +@example $ gnatls -d demo2.o ./demo2.o demo2 OK demo2.adb OK gen_list.ads @@ -16842,3990 +23717,1370 @@ instr.ads /home/comar/local/adainclude/s-tasoli.ads /home/comar/local/adainclude/s-unstyp.ads /home/comar/local/adainclude/unchconv.ads -@end smallexample - - -@node Cleaning Up with gnatclean -@chapter Cleaning Up with @code{gnatclean} -@findex gnatclean -@cindex Cleaning tool - -@noindent -@code{gnatclean} is a tool that allows the deletion of files produced by the -compiler, binder and linker, including ALI files, object files, tree files, -expanded source files, library files, interface copy source files, binder -generated files and executable files. - -@menu -* Running gnatclean:: -* Switches for gnatclean:: -@c * Examples of gnatclean Usage:: -@end menu - -@node Running gnatclean -@section Running @code{gnatclean} - -@noindent -The @code{gnatclean} command has the form: - -@smallexample -$ gnatclean switches @var{names} -@end smallexample - -@noindent -@var{names} is a list of source file names. Suffixes @code{.ads} and -@code{adb} may be omitted. If a project file is specified using switch -@code{-P}, then @var{names} may be completely omitted. - -@noindent -In normal mode, @code{gnatclean} delete the files produced by the compiler and, -if switch @code{-c} is not specified, by the binder and -the linker. In informative-only mode, specified by switch -@code{-n}, the list of files that would have been deleted in -normal mode is listed, but no file is actually deleted. - -@node Switches for gnatclean -@section Switches for @code{gnatclean} - -@noindent -@code{gnatclean} recognizes the following switches: - -@table @option -@c !sort! -@cindex @option{--version} @command{gnatclean} -Display Copyright and version, then exit disregarding all other options. - -@item --help -@cindex @option{--help} @command{gnatclean} -If @option{--version} was not used, display usage, then exit disregarding -all other options. - -@item --subdirs=subdir -Actual object directory of each project file is the subdirectory subdir of the -object directory specified or defaulted in the project file. - -@item --unchecked-shared-lib-imports -By default, shared library projects are not allowed to import static library -projects. When this switch is used on the command line, this restriction is -relaxed. - -@item -c -@cindex @option{-c} (@code{gnatclean}) -Only attempt to delete the files produced by the compiler, not those produced -by the binder or the linker. The files that are not to be deleted are library -files, interface copy files, binder generated files and executable files. - -@item -D @var{dir} -@cindex @option{-D} (@code{gnatclean}) -Indicate that ALI and object files should normally be found in directory -@var{dir}. - -@item -F -@cindex @option{-F} (@code{gnatclean}) -When using project files, if some errors or warnings are detected during -parsing and verbose mode is not in effect (no use of switch --v), then error lines start with the full path name of the project -file, rather than its simple file name. - -@item -h -@cindex @option{-h} (@code{gnatclean}) -Output a message explaining the usage of @code{gnatclean}. - -@item -n -@cindex @option{-n} (@code{gnatclean}) -Informative-only mode. Do not delete any files. Output the list of the files -that would have been deleted if this switch was not specified. - -@item -P@var{project} -@cindex @option{-P} (@code{gnatclean}) -Use project file @var{project}. Only one such switch can be used. -When cleaning a project file, the files produced by the compilation of the -immediate sources or inherited sources of the project files are to be -deleted. This is not depending on the presence or not of executable names -on the command line. - -@item -q -@cindex @option{-q} (@code{gnatclean}) -Quiet output. If there are no errors, do not output anything, except in -verbose mode (switch -v) or in informative-only mode -(switch -n). - -@item -r -@cindex @option{-r} (@code{gnatclean}) -When a project file is specified (using switch -P), -clean all imported and extended project files, recursively. If this switch -is not specified, only the files related to the main project file are to be -deleted. This switch has no effect if no project file is specified. - -@item -v -@cindex @option{-v} (@code{gnatclean}) -Verbose mode. +@end example +@end quotation -@item -vP@emph{x} -@cindex @option{-vP} (@code{gnatclean}) -Indicates the verbosity of the parsing of GNAT project files. -@xref{Switches Related to Project Files}. +@node The Cross-Referencing Tools gnatxref and gnatfind,The Ada to HTML Converter gnathtml,The GNAT Library Browser gnatls,GNAT Utility Programs +@anchor{gnat_ugn/gnat_utility_programs the-cross-referencing-tools-gnatxref-and-gnatfind}@anchor{24}@anchor{gnat_ugn/gnat_utility_programs id9}@anchor{1da} +@section The Cross-Referencing Tools @cite{gnatxref} and @cite{gnatfind} -@item -X@var{name=value} -@cindex @option{-X} (@code{gnatclean}) -Indicates that external variable @var{name} has the value @var{value}. -The Project Manager will use this value for occurrences of -@code{external(name)} when parsing the project file. -@xref{Switches Related to Project Files}. -@item -aO@var{dir} -@cindex @option{-aO} (@code{gnatclean}) -When searching for ALI and object files, look in directory -@var{dir}. +@geindex gnatxref -@item -I@var{dir} -@cindex @option{-I} (@code{gnatclean}) -Equivalent to @option{-aO@var{dir}}. +@geindex gnatfind -@item -I- -@cindex @option{-I-} (@code{gnatclean}) -@cindex Source files, suppressing search -Do not look for ALI or object files in the directory -where @code{gnatclean} was invoked. +The compiler generates cross-referencing information (unless +you set the @code{-gnatx} switch), which are saved in the @code{.ali} files. +This information indicates where in the source each entity is declared and +referenced. Note that entities in package Standard are not included, but +entities in all other predefined units are included in the output. -@end table +Before using any of these two tools, you need to compile successfully your +application, so that GNAT gets a chance to generate the cross-referencing +information. -@c @node Examples of gnatclean Usage -@c @section Examples of @code{gnatclean} Usage +The two tools @cite{gnatxref} and @cite{gnatfind} take advantage of this +information to provide the user with the capability to easily locate the +declaration and references to an entity. These tools are quite similar, +the difference being that @cite{gnatfind} is intended for locating +definitions and/or references to a specified entity or entities, whereas +@cite{gnatxref} is oriented to generating a full report of all +cross-references. -@node GNAT and Libraries -@chapter GNAT and Libraries -@cindex Library, building, installing, using +To use these tools, you must not compile your application using the +@emph{-gnatx} switch on the @emph{gnatmake} command line +(see @ref{1d,,Building with gnatmake}). Otherwise, cross-referencing +information will not be generated. -@noindent -This chapter describes how to build and use libraries with GNAT, and also shows -how to recompile the GNAT run-time library. You should be familiar with the -Project Manager facility (@pxref{GNAT Project Manager}) before reading this -chapter. +Note: to invoke @cite{gnatxref} or @cite{gnatfind} with a project file, +use the @cite{gnat} driver (see @ref{11f,,The GNAT Driver and Project Files}). @menu -* Introduction to Libraries in GNAT:: -* General Ada Libraries:: -* Stand-alone Ada Libraries:: -* Rebuilding the GNAT Run-Time Library:: -@end menu +* gnatxref Switches:: +* gnatfind Switches:: +* Project Files for gnatxref and gnatfind:: +* Regular Expressions in gnatfind and gnatxref:: +* Examples of gnatxref Usage:: +* Examples of gnatfind Usage:: -@node Introduction to Libraries in GNAT -@section Introduction to Libraries in GNAT +@end menu -@noindent -A library is, conceptually, a collection of objects which does not have its -own main thread of execution, but rather provides certain services to the -applications that use it. A library can be either statically linked with the -application, in which case its code is directly included in the application, -or, on platforms that support it, be dynamically linked, in which case -its code is shared by all applications making use of this library. +@node gnatxref Switches,gnatfind Switches,,The Cross-Referencing Tools gnatxref and gnatfind +@anchor{gnat_ugn/gnat_utility_programs id10}@anchor{1db}@anchor{gnat_ugn/gnat_utility_programs gnatxref-switches}@anchor{1dc} +@subsection @cite{gnatxref} Switches -GNAT supports both types of libraries. -In the static case, the compiled code can be provided in different ways. The -simplest approach is to provide directly the set of objects resulting from -compilation of the library source files. Alternatively, you can group the -objects into an archive using whatever commands are provided by the operating -system. For the latter case, the objects are grouped into a shared library. -In the GNAT environment, a library has three types of components: -@itemize @bullet -@item -Source files. -@item -@file{ALI} files. -@xref{The Ada Library Information Files}. -@item -Object files, an archive or a shared library. -@end itemize +The command invocation for @cite{gnatxref} is: -@noindent -A GNAT library may expose all its source files, which is useful for -documentation purposes. Alternatively, it may expose only the units needed by -an external user to make use of the library. That is to say, the specs -reflecting the library services along with all the units needed to compile -those specs, which can include generic bodies or any body implementing an -inlined routine. In the case of @emph{stand-alone libraries} those exposed -units are called @emph{interface units} (@pxref{Stand-alone Ada Libraries}). +@quotation -All compilation units comprising an application, including those in a library, -need to be elaborated in an order partially defined by Ada's semantics. GNAT -computes the elaboration order from the @file{ALI} files and this is why they -constitute a mandatory part of GNAT libraries. -@emph{Stand-alone libraries} are the exception to this rule because a specific -library elaboration routine is produced independently of the application(s) -using the library. +@example +$ gnatxref [`switches`] `sourcefile1` [`sourcefile2` ...] +@end example +@end quotation -@node General Ada Libraries -@section General Ada Libraries +where -@menu -* Building a library:: -* Installing a library:: -* Using a library:: -@end menu -@node Building a library -@subsection Building a library +@table @asis -@noindent -The easiest way to build a library is to use the Project Manager, -which supports a special type of project called a @emph{Library Project} -(@pxref{Library Projects}). +@item @emph{sourcefile1} [, @emph{sourcefile2} ...] -A project is considered a library project, when two project-level attributes -are defined in it: @code{Library_Name} and @code{Library_Dir}. In order to -control different aspects of library configuration, additional optional -project-level attributes can be specified: -@table @code -@item Library_Kind -This attribute controls whether the library is to be static or dynamic +identify the source files for which a report is to be generated. The +'with'ed units will be processed too. You must provide at least one file. -@item Library_Version -This attribute specifies the library version; this value is used -during dynamic linking of shared libraries to determine if the currently -installed versions of the binaries are compatible. +These file names are considered to be regular expressions, so for instance +specifying @code{source*.adb} is the same as giving every file in the current +directory whose name starts with @code{source} and whose extension is +@code{adb}. -@item Library_Options -@item Library_GCC -These attributes specify additional low-level options to be used during -library generation, and redefine the actual application used to generate -library. +You shouldn't specify any directory name, just base names. @emph{gnatxref} +and @emph{gnatfind} will be able to locate these files by themselves using +the source path. If you specify directories, no result is produced. @end table -@noindent -The GNAT Project Manager takes full care of the library maintenance task, -including recompilation of the source files for which objects do not exist -or are not up to date, assembly of the library archive, and installation of -the library (i.e., copying associated source, object and @file{ALI} files -to the specified location). - -Here is a simple library project file: -@smallexample @c ada -project My_Lib @b{is} - @b{for} Source_Dirs @b{use} ("src1", "src2"); - @b{for} Object_Dir @b{use} "obj"; - @b{for} Library_Name @b{use} "mylib"; - @b{for} Library_Dir @b{use} "lib"; - @b{for} Library_Kind @b{use} "dynamic"; -@b{end} My_lib; -@end smallexample - -@noindent -and the compilation command to build and install the library: - -@smallexample @c ada - $ gnatmake -Pmy_lib -@end smallexample - -@noindent -It is not entirely trivial to perform manually all the steps required to -produce a library. We recommend that you use the GNAT Project Manager -for this task. In special cases where this is not desired, the necessary -steps are discussed below. +The following switches are available for @emph{gnatxref}: -There are various possibilities for compiling the units that make up the -library: for example with a Makefile (@pxref{Using the GNU make Utility}) or -with a conventional script. For simple libraries, it is also possible to create -a dummy main program which depends upon all the packages that comprise the -interface of the library. This dummy main program can then be given to -@command{gnatmake}, which will ensure that all necessary objects are built. +@geindex --version (gnatxref) -After this task is accomplished, you should follow the standard procedure -of the underlying operating system to produce the static or shared library. -Here is an example of such a dummy program: -@smallexample @c ada -@group -@b{with} My_Lib.Service1; -@b{with} My_Lib.Service2; -@b{with} My_Lib.Service3; -@b{procedure} My_Lib_Dummy @b{is} -@b{begin} - @b{null}; -@b{end}; -@end group -@end smallexample - -@noindent -Here are the generic commands that will build an archive or a shared library. +@table @asis -@smallexample -# compiling the library -$ gnatmake -c my_lib_dummy.adb +@item @code{-version} -# we don't need the dummy object itself -$ rm my_lib_dummy.o my_lib_dummy.ali +Display Copyright and version, then exit disregarding all other options. +@end table -# create an archive with the remaining objects -$ ar rc libmy_lib.a *.o -# some systems may require "ranlib" to be run as well +@geindex --help (gnatxref) -# or create a shared library -$ gcc -shared -o libmy_lib.so *.o -# some systems may require the code to have been compiled with -fPIC -# remove the object files that are now in the library -$ rm *.o +@table @asis -# Make the ALI files read-only so that gnatmake will not try to -# regenerate the objects that are in the library -$ chmod -w *.ali -@end smallexample +@item @code{-help} -@noindent -Please note that the library must have a name of the form @file{lib@var{xxx}.a} -or @file{lib@var{xxx}.so} (or @file{lib@var{xxx}.dll} on Windows) in order to -be accessed by the directive @option{-l@var{xxx}} at link time. +If @emph{--version} was not used, display usage, then exit disregarding +all other options. +@end table -@node Installing a library -@subsection Installing a library -@cindex @code{ADA_PROJECT_PATH} -@cindex @code{GPR_PROJECT_PATH} +@geindex -a (gnatxref) -@noindent -If you use project files, library installation is part of the library build -process (@pxref{Installing a library with project files}). -When project files are not an option, it is also possible, but not recommended, -to install the library so that the sources needed to use the library are on the -Ada source path and the ALI files & libraries be on the Ada Object path (see -@ref{Search Paths and the Run-Time Library (RTL)}. Alternatively, the system -administrator can place general-purpose libraries in the default compiler -paths, by specifying the libraries' location in the configuration files -@file{ada_source_path} and @file{ada_object_path}. These configuration files -must be located in the GNAT installation tree at the same place as the gcc spec -file. The location of the gcc spec file can be determined as follows: -@smallexample -$ gcc -v -@end smallexample +@table @asis -@noindent -The configuration files mentioned above have a simple format: each line -must contain one unique directory name. -Those names are added to the corresponding path -in their order of appearance in the file. The names can be either absolute -or relative; in the latter case, they are relative to where theses files -are located. +@item @code{a} -The files @file{ada_source_path} and @file{ada_object_path} might not be -present in a -GNAT installation, in which case, GNAT will look for its run-time library in -the directories @file{adainclude} (for the sources) and @file{adalib} (for the -objects and @file{ALI} files). When the files exist, the compiler does not -look in @file{adainclude} and @file{adalib}, and thus the -@file{ada_source_path} file -must contain the location for the GNAT run-time sources (which can simply -be @file{adainclude}). In the same way, the @file{ada_object_path} file must -contain the location for the GNAT run-time objects (which can simply -be @file{adalib}). +If this switch is present, @cite{gnatfind} and @cite{gnatxref} will parse +the read-only files found in the library search path. Otherwise, these files +will be ignored. This option can be used to protect Gnat sources or your own +libraries from being parsed, thus making @cite{gnatfind} and @cite{gnatxref} +much faster, and their output much smaller. Read-only here refers to access +or permissions status in the file system for the current user. +@end table -You can also specify a new default path to the run-time library at compilation -time with the switch @option{--RTS=rts-path}. You can thus choose / change -the run-time library you want your program to be compiled with. This switch is -recognized by @command{gcc}, @command{gnatmake}, @command{gnatbind}, -@command{gnatls}, @command{gnatfind} and @command{gnatxref}. +@geindex -aIDIR (gnatxref) -It is possible to install a library before or after the standard GNAT -library, by reordering the lines in the configuration files. In general, a -library must be installed before the GNAT library if it redefines -any part of it. -@node Using a library -@subsection Using a library +@table @asis -@noindent Once again, the project facility greatly simplifies the use of -libraries. In this context, using a library is just a matter of adding a -@code{with} clause in the user project. For instance, to make use of the -library @code{My_Lib} shown in examples in earlier sections, you can -write: +@item @code{aI@emph{DIR}} -@smallexample @c projectfile -@b{with} "my_lib"; -@b{project} My_Proj @b{is} - @dots{} -@b{end} My_Proj; -@end smallexample +When looking for source files also look in directory DIR. The order in which +source file search is undertaken is the same as for @emph{gnatmake}. +@end table -Even if you have a third-party, non-Ada library, you can still use GNAT's -Project Manager facility to provide a wrapper for it. For example, the -following project, when @code{with}ed by your main project, will link with the -third-party library @file{liba.a}: - -@smallexample @c projectfile -@group -@b{project} Liba @b{is} - @b{for} Externally_Built @b{use} "true"; - @b{for} Source_Files @b{use} (); - @b{for} Library_Dir @b{use} "lib"; - @b{for} Library_Name @b{use} "a"; - @b{for} Library_Kind @b{use} "static"; -@b{end} Liba; -@end group -@end smallexample -This is an alternative to the use of @code{pragma Linker_Options}. It is -especially interesting in the context of systems with several interdependent -static libraries where finding a proper linker order is not easy and best be -left to the tools having visibility over project dependence information. +@geindex -aODIR (gnatxref) -@noindent -In order to use an Ada library manually, you need to make sure that this -library is on both your source and object path -(see @ref{Search Paths and the Run-Time Library (RTL)} -and @ref{Search Paths for gnatbind}). Furthermore, when the objects are grouped -in an archive or a shared library, you need to specify the desired -library at link time. -For example, you can use the library @file{mylib} installed in -@file{/dir/my_lib_src} and @file{/dir/my_lib_obj} with the following commands: +@table @asis -@smallexample -$ gnatmake -aI/dir/my_lib_src -aO/dir/my_lib_obj my_appl \ - -largs -lmy_lib -@end smallexample +@item @code{aO@emph{DIR}} -@noindent -This can be expressed more simply: -@smallexample -$ gnatmake my_appl -@end smallexample -@noindent -when the following conditions are met: -@itemize @bullet -@item -@file{/dir/my_lib_src} has been added by the user to the environment -variable @env{ADA_INCLUDE_PATH}, or by the administrator to the file -@file{ada_source_path} -@item -@file{/dir/my_lib_obj} has been added by the user to the environment -variable @env{ADA_OBJECTS_PATH}, or by the administrator to the file -@file{ada_object_path} -@item -a pragma @code{Linker_Options} has been added to one of the sources. -For example: +When searching for library and object files, look in directory +DIR. The order in which library files are searched is the same as for +@emph{gnatmake}. +@end table -@smallexample @c ada -@b{pragma} Linker_Options ("-lmy_lib"); -@end smallexample -@end itemize +@geindex -nostdinc (gnatxref) -Note that you may also load a library dynamically at -run time given its filename, as illustrated in the GNAT @file{plugins} example -in the directory @file{share/examples/gnat/plugins} within the GNAT -install area. -@node Stand-alone Ada Libraries -@section Stand-alone Ada Libraries -@cindex Stand-alone library, building, using +@table @asis -@menu -* Introduction to Stand-alone Libraries:: -* Building a Stand-alone Library:: -* Creating a Stand-alone Library to be used in a non-Ada context:: -* Restrictions in Stand-alone Libraries:: -@end menu +@item @code{nostdinc} -@node Introduction to Stand-alone Libraries -@subsection Introduction to Stand-alone Libraries +Do not look for sources in the system default directory. +@end table -@noindent -A Stand-alone Library (abbreviated ``SAL'') is a library that contains the -necessary code to -elaborate the Ada units that are included in the library. In contrast with -an ordinary library, which consists of all sources, objects and @file{ALI} -files of the -library, a SAL may specify a restricted subset of compilation units -to serve as a library interface. In this case, the fully -self-sufficient set of files will normally consist of an objects -archive, the sources of interface units' specs, and the @file{ALI} -files of interface units. -If an interface spec contains a generic unit or an inlined subprogram, -the body's -source must also be provided; if the units that must be provided in the source -form depend on other units, the source and @file{ALI} files of those must -also be provided. +@geindex -nostdlib (gnatxref) -The main purpose of a SAL is to minimize the recompilation overhead of client -applications when a new version of the library is installed. Specifically, -if the interface sources have not changed, client applications do not need to -be recompiled. If, furthermore, a SAL is provided in the shared form and its -version, controlled by @code{Library_Version} attribute, is not changed, -then the clients do not need to be relinked. -SALs also allow the library providers to minimize the amount of library source -text exposed to the clients. Such ``information hiding'' might be useful or -necessary for various reasons. +@table @asis -Stand-alone libraries are also well suited to be used in an executable whose -main routine is not written in Ada. +@item @code{nostdlib} -@node Building a Stand-alone Library -@subsection Building a Stand-alone Library +Do not look for library files in the system default directory. +@end table -@noindent -GNAT's Project facility provides a simple way of building and installing -stand-alone libraries; see @ref{Stand-alone Library Projects}. -To be a Stand-alone Library Project, in addition to the two attributes -that make a project a Library Project (@code{Library_Name} and -@code{Library_Dir}; see @ref{Library Projects}), the attribute -@code{Library_Interface} must be defined. For example: - -@smallexample @c projectfile -@group - @b{for} Library_Dir @b{use} "lib_dir"; - @b{for} Library_Name @b{use} "dummy"; - @b{for} Library_Interface @b{use} ("int1", "int1.child"); -@end group -@end smallexample - -@noindent -Attribute @code{Library_Interface} has a non-empty string list value, -each string in the list designating a unit contained in an immediate source -of the project file. +@geindex --ext (gnatxref) -When a Stand-alone Library is built, first the binder is invoked to build -a package whose name depends on the library name -(@file{b~dummy.ads/b} in the example above). -This binder-generated package includes initialization and -finalization procedures whose -names depend on the library name (@code{dummyinit} and @code{dummyfinal} -in the example -above). The object corresponding to this package is included in the library. -You must ensure timely (e.g., prior to any use of interfaces in the SAL) -calling of these procedures if a static SAL is built, or if a shared SAL -is built -with the project-level attribute @code{Library_Auto_Init} set to -@code{"false"}. +@table @asis -For a Stand-Alone Library, only the @file{ALI} files of the Interface Units -(those that are listed in attribute @code{Library_Interface}) are copied to -the Library Directory. As a consequence, only the Interface Units may be -imported from Ada units outside of the library. If other units are imported, -the binding phase will fail. +@item @code{-ext=@emph{extension}} -@noindent -It is also possible to build an encapsulated library where not only -the code to elaborate and finalize the library is embedded but also -ensuring that the library is linked only against static -libraries. So an encapsulated library only depends on system -libraries, all other code, including the GNAT runtime, is embedded. To -build an encapsulated library the attribute -@code{Library_Standalone} must be set to @code{encapsulated}: - -@smallexample @c projectfile -@group - @b{for} Library_Dir @b{use} "lib_dir"; - @b{for} Library_Name @b{use} "dummy"; - @b{for} Library_Kind @b{use} "dynamic"; - @b{for} Library_Interface @b{use} ("int1", "int1.child"); - @b{for} Library_Standalone @b{use} "encapsulated"; -@end group -@end smallexample - -@noindent -The default value for this attribute is @code{standard} in which case -a stand-alone library is built. +Specify an alternate ali file extension. The default is @cite{ali} and other +extensions (e.g. @cite{gli} for C/C++ sources when using @emph{-fdump-xref}) +may be specified via this switch. Note that if this switch overrides the +default, which means that only the new extension will be considered. +@end table -The attribute @code{Library_Src_Dir} may be specified for a -Stand-Alone Library. @code{Library_Src_Dir} is a simple attribute that has a -single string value. Its value must be the path (absolute or relative to the -project directory) of an existing directory. This directory cannot be the -object directory or one of the source directories, but it can be the same as -the library directory. The sources of the Interface -Units of the library that are needed by an Ada client of the library will be -copied to the designated directory, called the Interface Copy directory. -These sources include the specs of the Interface Units, but they may also -include bodies and subunits, when pragmas @code{Inline} or @code{Inline_Always} -are used, or when there is a generic unit in the spec. Before the sources -are copied to the Interface Copy directory, an attempt is made to delete all -files in the Interface Copy directory. +@geindex --RTS (gnatxref) -Building stand-alone libraries by hand is somewhat tedious, but for those -occasions when it is necessary here are the steps that you need to perform: -@itemize @bullet -@item -Compile all library sources. -@item -Invoke the binder with the switch @option{-n} (No Ada main program), -with all the @file{ALI} files of the interfaces, and -with the switch @option{-L} to give specific names to the @code{init} -and @code{final} procedures. For example: -@smallexample - gnatbind -n int1.ali int2.ali -Lsal1 -@end smallexample +@table @asis -@item -Compile the binder generated file: -@smallexample - gcc -c b~int2.adb -@end smallexample +@item @code{-RTS=@emph{rts-path}} -@item -Link the dynamic library with all the necessary object files, -indicating to the linker the names of the @code{init} (and possibly -@code{final}) procedures for automatic initialization (and finalization). -The built library should be placed in a directory different from -the object directory. +Specifies the default location of the runtime library. Same meaning as the +equivalent @emph{gnatmake} flag (@ref{df,,Switches for gnatmake}). +@end table -@item -Copy the @code{ALI} files of the interface to the library directory, -add in this copy an indication that it is an interface to a SAL -(i.e., add a word @option{SL} on the line in the @file{ALI} file that starts -with letter ``P'') and make the modified copy of the @file{ALI} file -read-only. -@end itemize +@geindex -d (gnatxref) -@noindent -Using SALs is not different from using other libraries -(see @ref{Using a library}). -@node Creating a Stand-alone Library to be used in a non-Ada context -@subsection Creating a Stand-alone Library to be used in a non-Ada context +@table @asis -@noindent -It is easy to adapt the SAL build procedure discussed above for use of a SAL in -a non-Ada context. +@item @code{d} -The only extra step required is to ensure that library interface subprograms -are compatible with the main program, by means of @code{pragma Export} -or @code{pragma Convention}. +If this switch is set @cite{gnatxref} will output the parent type +reference for each matching derived types. +@end table -Here is an example of simple library interface for use with C main program: +@geindex -f (gnatxref) -@smallexample @c ada -@b{package} My_Package @b{is} - @b{procedure} Do_Something; - @b{pragma} Export (C, Do_Something, "do_something"); +@table @asis - @b{procedure} Do_Something_Else; - @b{pragma} Export (C, Do_Something_Else, "do_something_else"); +@item @code{f} -@b{end} My_Package; -@end smallexample +If this switch is set, the output file names will be preceded by their +directory (if the file was found in the search path). If this switch is +not set, the directory will not be printed. +@end table -@noindent -On the foreign language side, you must provide a ``foreign'' view of the -library interface; remember that it should contain elaboration routines in -addition to interface subprograms. +@geindex -g (gnatxref) -The example below shows the content of @code{mylib_interface.h} (note -that there is no rule for the naming of this file, any name can be used) -@smallexample -/* the library elaboration procedure */ -extern void mylibinit (void); -/* the library finalization procedure */ -extern void mylibfinal (void); +@table @asis -/* the interface exported by the library */ -extern void do_something (void); -extern void do_something_else (void); -@end smallexample +@item @code{g} -@noindent -Libraries built as explained above can be used from any program, provided -that the elaboration procedures (named @code{mylibinit} in the previous -example) are called before the library services are used. Any number of -libraries can be used simultaneously, as long as the elaboration -procedure of each library is called. +If this switch is set, information is output only for library-level +entities, ignoring local entities. The use of this switch may accelerate +@cite{gnatfind} and @cite{gnatxref}. +@end table -Below is an example of a C program that uses the @code{mylib} library. +@geindex -IDIR (gnatxref) -@smallexample -#include "mylib_interface.h" -int -main (void) -@{ - /* First, elaborate the library before using it */ - mylibinit (); +@table @asis - /* Main program, using the library exported entities */ - do_something (); - do_something_else (); +@item @code{I@emph{DIR}} - /* Library finalization at the end of the program */ - mylibfinal (); - return 0; -@} -@end smallexample +Equivalent to @code{-aODIR -aIDIR}. +@end table -@noindent -Note that invoking any library finalization procedure generated by -@code{gnatbind} shuts down the Ada run-time environment. -Consequently, the -finalization of all Ada libraries must be performed at the end of the program. -No call to these libraries or to the Ada run-time library should be made -after the finalization phase. +@geindex -pFILE (gnatxref) -@noindent -Note also that special care must be taken with multi-tasks -applications. The initialization and finalization routines are not -protected against concurrent access. If such requirement is needed it -must be ensured at the application level using a specific operating -system services like a mutex or a critical-section. -@node Restrictions in Stand-alone Libraries -@subsection Restrictions in Stand-alone Libraries +@table @asis -@noindent -The pragmas listed below should be used with caution inside libraries, -as they can create incompatibilities with other Ada libraries: -@itemize @bullet -@item pragma @code{Locking_Policy} -@item pragma @code{Partition_Elaboration_Policy} -@item pragma @code{Queuing_Policy} -@item pragma @code{Task_Dispatching_Policy} -@item pragma @code{Unreserve_All_Interrupts} -@end itemize +@item @code{p@emph{FILE}} -@noindent -When using a library that contains such pragmas, the user must make sure -that all libraries use the same pragmas with the same values. Otherwise, -@code{Program_Error} will -be raised during the elaboration of the conflicting -libraries. The usage of these pragmas and its consequences for the user -should therefore be well documented. +Specify a project file to use @ref{b,,GNAT Project Manager}. +If you need to use the @code{.gpr} +project files, you should use gnatxref through the GNAT driver +(@emph{gnat xref -Pproject}). -Similarly, the traceback in the exception occurrence mechanism should be -enabled or disabled in a consistent manner across all libraries. -Otherwise, Program_Error will be raised during the elaboration of the -conflicting libraries. +By default, @cite{gnatxref} and @cite{gnatfind} will try to locate a +project file in the current directory. -If the @code{Version} or @code{Body_Version} -attributes are used inside a library, then you need to -perform a @code{gnatbind} step that specifies all @file{ALI} files in all -libraries, so that version identifiers can be properly computed. -In practice these attributes are rarely used, so this is unlikely -to be a consideration. +If a project file is either specified or found by the tools, then the content +of the source directory and object directory lines are added as if they +had been specified respectively by @code{-aI} +and @code{-aO}. -@node Rebuilding the GNAT Run-Time Library -@section Rebuilding the GNAT Run-Time Library -@cindex GNAT Run-Time Library, rebuilding -@cindex Building the GNAT Run-Time Library -@cindex Rebuilding the GNAT Run-Time Library -@cindex Run-Time Library, rebuilding +@item @code{u} -@noindent -It may be useful to recompile the GNAT library in various contexts, the -most important one being the use of partition-wide configuration pragmas -such as @code{Normalize_Scalars}. A special Makefile called -@code{Makefile.adalib} is provided to that effect and can be found in -the directory containing the GNAT library. The location of this -directory depends on the way the GNAT environment has been installed and can -be determined by means of the command: +Output only unused symbols. This may be really useful if you give your +main compilation unit on the command line, as @cite{gnatxref} will then +display every unused entity and 'with'ed package. -@smallexample -$ gnatls -v -@end smallexample +@item @code{v} -@noindent -The last entry in the object search path usually contains the -gnat library. This Makefile contains its own documentation and in -particular the set of instructions needed to rebuild a new library and -to use it. +Instead of producing the default output, @cite{gnatxref} will generate a +@code{tags} file that can be used by vi. For examples how to use this +feature, see @ref{1dd,,Examples of gnatxref Usage}. The tags file is output +to the standard output, thus you will have to redirect it to a file. +@end table -@node Using the GNU make Utility -@chapter Using the GNU @code{make} Utility -@findex make +All these switches may be in any order on the command line, and may even +appear after the file names. They need not be separated by spaces, thus +you can say @code{gnatxref -ag} instead of @code{gnatxref -a -g}. -@noindent -This chapter offers some examples of makefiles that solve specific -problems. It does not explain how to write a makefile (@pxref{Top,, GNU -make, make, GNU @code{make}}), nor does it try to replace the -@command{gnatmake} utility (@pxref{The GNAT Make Program gnatmake}). +@node gnatfind Switches,Project Files for gnatxref and gnatfind,gnatxref Switches,The Cross-Referencing Tools gnatxref and gnatfind +@anchor{gnat_ugn/gnat_utility_programs id11}@anchor{1de}@anchor{gnat_ugn/gnat_utility_programs gnatfind-switches}@anchor{1df} +@subsection @cite{gnatfind} Switches -All the examples in this section are specific to the GNU version of -make. Although @command{make} is a standard utility, and the basic language -is the same, these examples use some advanced features found only in -@code{GNU make}. -@menu -* Using gnatmake in a Makefile:: -* Automatically Creating a List of Directories:: -* Generating the Command Line Switches:: -* Overcoming Command Line Length Limits:: -@end menu +The command invocation for @cite{gnatfind} is: -@node Using gnatmake in a Makefile -@section Using gnatmake in a Makefile -@findex makefile -@cindex GNU make +@quotation -@noindent -Complex project organizations can be handled in a very powerful way by -using GNU make combined with gnatmake. For instance, here is a Makefile -which allows you to build each subsystem of a big project into a separate -shared library. Such a makefile allows you to significantly reduce the link -time of very big applications while maintaining full coherence at -each step of the build process. +@example +$ gnatfind [`switches`] `pattern`[:`sourcefile`[:`line`[:`column`]]] + [`file1` `file2` ...] +@end example +@end quotation -The list of dependencies are handled automatically by -@command{gnatmake}. The Makefile is simply used to call gnatmake in each of -the appropriate directories. +with the following iterpretation of the command arguments: -Note that you should also read the example on how to automatically -create the list of directories -(@pxref{Automatically Creating a List of Directories}) -which might help you in case your project has a lot of subdirectories. -@smallexample -@iftex -@leftskip=0cm -@font@heightrm=cmr8 -@heightrm -@end iftex -## This Makefile is intended to be used with the following directory -## configuration: -## - The sources are split into a series of csc (computer software components) -## Each of these csc is put in its own directory. -## Their name are referenced by the directory names. -## They will be compiled into shared library (although this would also work -## with static libraries -## - The main program (and possibly other packages that do not belong to any -## csc is put in the top level directory (where the Makefile is). -## toplevel_dir __ first_csc (sources) __ lib (will contain the library) -## \_ second_csc (sources) __ lib (will contain the library) -## \_ @dots{} -## Although this Makefile is build for shared library, it is easy to modify -## to build partial link objects instead (modify the lines with -shared and -## gnatlink below) -## -## With this makefile, you can change any file in the system or add any new -## file, and everything will be recompiled correctly (only the relevant shared -## objects will be recompiled, and the main program will be re-linked). +@table @asis -# The list of computer software component for your project. This might be -# generated automatically. -CSC_LIST=aa bb cc +@item @emph{pattern} -# Name of the main program (no extension) -MAIN=main +An entity will be output only if it matches the regular expression found +in @cite{pattern}, see @ref{1e0,,Regular Expressions in gnatfind and gnatxref}. -# If we need to build objects with -fPIC, uncomment the following line -#NEED_FPIC=-fPIC +Omitting the pattern is equivalent to specifying @code{*}, which +will match any entity. Note that if you do not provide a pattern, you +have to provide both a sourcefile and a line. -# The following variable should give the directory containing libgnat.so -# You can get this directory through 'gnatls -v'. This is usually the last -# directory in the Object_Path. -GLIB=@dots{} +Entity names are given in Latin-1, with uppercase/lowercase equivalence +for matching purposes. At the current time there is no support for +8-bit codes other than Latin-1, or for wide characters in identifiers. -# The directories for the libraries -# (This macro expands the list of CSC to the list of shared libraries, you -# could simply use the expanded form: -# LIB_DIR=aa/lib/libaa.so bb/lib/libbb.so cc/lib/libcc.so -LIB_DIR=$@{foreach dir,$@{CSC_LIST@},$@{dir@}/lib/lib$@{dir@}.so@} +@item @emph{sourcefile} -$@{MAIN@}: objects $@{LIB_DIR@} - gnatbind $@{MAIN@} $@{CSC_LIST:%=-aO%/lib@} -shared - gnatlink $@{MAIN@} $@{CSC_LIST:%=-l%@} +@cite{gnatfind} will look for references, bodies or declarations +of symbols referenced in @code{sourcefile}, at line @cite{line} +and column @cite{column}. See @ref{1e1,,Examples of gnatfind Usage} +for syntax examples. -objects:: - # recompile the sources - gnatmake -c -i $@{MAIN@}.adb $@{NEED_FPIC@} $@{CSC_LIST:%=-I%@} +@item @emph{line} -# Note: In a future version of GNAT, the following commands will be simplified -# by a new tool, gnatmlib -$@{LIB_DIR@}: - mkdir -p $@{dir $@@ @} - cd $@{dir $@@ @} && gcc -shared -o $@{notdir $@@ @} ../*.o -L$@{GLIB@} -lgnat - cd $@{dir $@@ @} && cp -f ../*.ali . +A decimal integer identifying the line number containing +the reference to the entity (or entities) to be located. -# The dependencies for the modules -# Note that we have to force the expansion of *.o, since in some cases -# make won't be able to do it itself. -aa/lib/libaa.so: $@{wildcard aa/*.o@} -bb/lib/libbb.so: $@{wildcard bb/*.o@} -cc/lib/libcc.so: $@{wildcard cc/*.o@} +@item @emph{column} -# Make sure all of the shared libraries are in the path before starting the -# program -run:: - LD_LIBRARY_PATH=`pwd`/aa/lib:`pwd`/bb/lib:`pwd`/cc/lib ./$@{MAIN@} +A decimal integer identifying the exact location on the +line of the first character of the identifier for the +entity reference. Columns are numbered from 1. -clean:: - $@{RM@} -rf $@{CSC_LIST:%=%/lib@} - $@{RM@} $@{CSC_LIST:%=%/*.ali@} - $@{RM@} $@{CSC_LIST:%=%/*.o@} - $@{RM@} *.o *.ali $@{MAIN@} -@end smallexample +@item @emph{file1 file2 ...} -@node Automatically Creating a List of Directories -@section Automatically Creating a List of Directories +The search will be restricted to these source files. If none are given, then +the search will be conducted for every library file in the search path. +These files must appear only after the pattern or sourcefile. -@noindent -In most makefiles, you will have to specify a list of directories, and -store it in a variable. For small projects, it is often easier to -specify each of them by hand, since you then have full control over what -is the proper order for these directories, which ones should be -included. +These file names are considered to be regular expressions, so for instance +specifying @code{source*.adb} is the same as giving every file in the current +directory whose name starts with @code{source} and whose extension is +@code{adb}. -However, in larger projects, which might involve hundreds of -subdirectories, it might be more convenient to generate this list -automatically. +The location of the spec of the entity will always be displayed, even if it +isn't in one of @code{file1}, @code{file2}, ... The +occurrences of the entity in the separate units of the ones given on the +command line will also be displayed. -The example below presents two methods. The first one, although less -general, gives you more control over the list. It involves wildcard -characters, that are automatically expanded by @command{make}. Its -shortcoming is that you need to explicitly specify some of the -organization of your project, such as for instance the directory tree -depth, whether some directories are found in a separate tree, @enddots{} +Note that if you specify at least one file in this part, @cite{gnatfind} may +sometimes not be able to find the body of the subprograms. +@end table -The second method is the most general one. It requires an external -program, called @command{find}, which is standard on all Unix systems. All -the directories found under a given root directory will be added to the -list. +At least one of 'sourcefile' or 'pattern' has to be present on +the command line. -@smallexample -@iftex -@leftskip=0cm -@font@heightrm=cmr8 -@heightrm -@end iftex -# The examples below are based on the following directory hierarchy: -# All the directories can contain any number of files -# ROOT_DIRECTORY -> a -> aa -> aaa -# -> ab -# -> ac -# -> b -> ba -> baa -# -> bb -# -> bc -# This Makefile creates a variable called DIRS, that can be reused any time -# you need this list (see the other examples in this section) +The following switches are available: -# The root of your project's directory hierarchy -ROOT_DIRECTORY=. +@geindex --version (gnatfind) -#### -# First method: specify explicitly the list of directories -# This allows you to specify any subset of all the directories you need. -#### -DIRS := a/aa/ a/ab/ b/ba/ +@table @asis -#### -# Second method: use wildcards -# Note that the argument(s) to wildcard below should end with a '/'. -# Since wildcards also return file names, we have to filter them out -# to avoid duplicate directory names. -# We thus use make's @code{dir} and @code{sort} functions. -# It sets DIRs to the following value (note that the directories aaa and baa -# are not given, unless you change the arguments to wildcard). -# DIRS= ./a/a/ ./b/ ./a/aa/ ./a/ab/ ./a/ac/ ./b/ba/ ./b/bb/ ./b/bc/ -#### +@item @code{--version} -DIRS := $@{sort $@{dir $@{wildcard $@{ROOT_DIRECTORY@}/*/ - $@{ROOT_DIRECTORY@}/*/*/@}@}@} +Display Copyright and version, then exit disregarding all other options. +@end table -#### -# Third method: use an external program -# This command is much faster if run on local disks, avoiding NFS slowdowns. -# This is the most complete command: it sets DIRs to the following value: -# DIRS= ./a ./a/aa ./a/aa/aaa ./a/ab ./a/ac ./b ./b/ba ./b/ba/baa ./b/bb ./b/bc -#### +@geindex --help (gnatfind) -DIRS := $@{shell find $@{ROOT_DIRECTORY@} -type d -print@} -@end smallexample +@table @asis -@node Generating the Command Line Switches -@section Generating the Command Line Switches +@item @code{-help} -@noindent -Once you have created the list of directories as explained in the -previous section (@pxref{Automatically Creating a List of Directories}), -you can easily generate the command line arguments to pass to gnatmake. +If @emph{--version} was not used, display usage, then exit disregarding +all other options. +@end table -For the sake of completeness, this example assumes that the source path -is not the same as the object path, and that you have two separate lists -of directories. +@geindex -a (gnatfind) -@smallexample -# see "Automatically creating a list of directories" to create -# these variables -SOURCE_DIRS= -OBJECT_DIRS= -GNATMAKE_SWITCHES := $@{patsubst %,-aI%,$@{SOURCE_DIRS@}@} -GNATMAKE_SWITCHES += $@{patsubst %,-aO%,$@{OBJECT_DIRS@}@} +@table @asis -all: - gnatmake $@{GNATMAKE_SWITCHES@} main_unit -@end smallexample +@item @code{a} -@node Overcoming Command Line Length Limits -@section Overcoming Command Line Length Limits +If this switch is present, @cite{gnatfind} and @cite{gnatxref} will parse +the read-only files found in the library search path. Otherwise, these files +will be ignored. This option can be used to protect Gnat sources or your own +libraries from being parsed, thus making @cite{gnatfind} and @cite{gnatxref} +much faster, and their output much smaller. Read-only here refers to access +or permission status in the file system for the current user. +@end table -@noindent -One problem that might be encountered on big projects is that many -operating systems limit the length of the command line. It is thus hard to give -gnatmake the list of source and object directories. +@geindex -aIDIR (gnatfind) -This example shows how you can set up environment variables, which will -make @command{gnatmake} behave exactly as if the directories had been -specified on the command line, but have a much higher length limit (or -even none on most systems). -It assumes that you have created a list of directories in your Makefile, -using one of the methods presented in -@ref{Automatically Creating a List of Directories}. -For the sake of completeness, we assume that the object -path (where the ALI files are found) is different from the sources patch. +@table @asis -Note a small trick in the Makefile below: for efficiency reasons, we -create two temporary variables (SOURCE_LIST and OBJECT_LIST), that are -expanded immediately by @code{make}. This way we overcome the standard -make behavior which is to expand the variables only when they are -actually used. +@item @code{aI@emph{DIR}} -On Windows, if you are using the standard Windows command shell, you must -replace colons with semicolons in the assignments to these variables. +When looking for source files also look in directory DIR. The order in which +source file search is undertaken is the same as for @emph{gnatmake}. +@end table -@smallexample -@iftex -@leftskip=0cm -@font@heightrm=cmr8 -@heightrm -@end iftex -# In this example, we create both ADA_INCLUDE_PATH and ADA_OBJECTS_PATH. -# This is the same thing as putting the -I arguments on the command line. -# (the equivalent of using -aI on the command line would be to define -# only ADA_INCLUDE_PATH, the equivalent of -aO is ADA_OBJECTS_PATH). -# You can of course have different values for these variables. -# -# Note also that we need to keep the previous values of these variables, since -# they might have been set before running 'make' to specify where the GNAT -# library is installed. +@geindex -aODIR (gnatfind) -# see "Automatically creating a list of directories" to create these -# variables -SOURCE_DIRS= -OBJECT_DIRS= -empty:= -space:=$@{empty@} $@{empty@} -SOURCE_LIST := $@{subst $@{space@},:,$@{SOURCE_DIRS@}@} -OBJECT_LIST := $@{subst $@{space@},:,$@{OBJECT_DIRS@}@} -ADA_INCLUDE_PATH += $@{SOURCE_LIST@} -ADA_OBJECTS_PATH += $@{OBJECT_LIST@} -export ADA_INCLUDE_PATH -export ADA_OBJECTS_PATH +@table @asis -all: - gnatmake main_unit -@end smallexample +@item @code{aO@emph{DIR}} -@node Memory Management Issues -@chapter Memory Management Issues +When searching for library and object files, look in directory +DIR. The order in which library files are searched is the same as for +@emph{gnatmake}. +@end table -@noindent -This chapter describes some useful memory pools provided in the GNAT library -and in particular the GNAT Debug Pool facility, which can be used to detect -incorrect uses of access values (including ``dangling references''). -@ifclear FSFEDITION -It also describes the @command{gnatmem} tool, which can be used to track down -``memory leaks''. -@end ifclear +@geindex -nostdinc (gnatfind) -@menu -* Some Useful Memory Pools:: -* The GNAT Debug Pool Facility:: -@ifclear FSFEDITION -* The gnatmem Tool:: -@end ifclear -@end menu -@node Some Useful Memory Pools -@section Some Useful Memory Pools -@findex Memory Pool -@cindex storage, pool +@table @asis -@noindent -The @code{System.Pool_Global} package offers the Unbounded_No_Reclaim_Pool -storage pool. Allocations use the standard system call @code{malloc} while -deallocations use the standard system call @code{free}. No reclamation is -performed when the pool goes out of scope. For performance reasons, the -standard default Ada allocators/deallocators do not use any explicit storage -pools but if they did, they could use this storage pool without any change in -behavior. That is why this storage pool is used when the user -manages to make the default implicit allocator explicit as in this example: -@smallexample @c ada - @b{type} T1 @b{is} @b{access} Something; - --@i{ no Storage pool is defined for T2} - @b{type} T2 @b{is} @b{access} Something_Else; - @b{for} T2'Storage_Pool @b{use} T1'Storage_Pool; - --@i{ the above is equivalent to} - @b{for} T2'Storage_Pool @b{use} System.Pool_Global.Global_Pool_Object; -@end smallexample - -@noindent -The @code{System.Pool_Local} package offers the Unbounded_Reclaim_Pool storage -pool. The allocation strategy is similar to @code{Pool_Local}'s -except that the all -storage allocated with this pool is reclaimed when the pool object goes out of -scope. This pool provides a explicit mechanism similar to the implicit one -provided by several Ada 83 compilers for allocations performed through a local -access type and whose purpose was to reclaim memory when exiting the -scope of a given local access. As an example, the following program does not -leak memory even though it does not perform explicit deallocation: +@item @code{nostdinc} -@smallexample @c ada -@b{with} System.Pool_Local; -@b{procedure} Pooloc1 @b{is} - @b{procedure} Internal @b{is} - @b{type} A @b{is} @b{access} Integer; - X : System.Pool_Local.Unbounded_Reclaim_Pool; - @b{for} A'Storage_Pool @b{use} X; - v : A; - @b{begin} - @b{for} I @b{in} 1 .. 50 @b{loop} - v := @b{new} Integer; - @b{end} @b{loop}; - @b{end} Internal; -@b{begin} - @b{for} I @b{in} 1 .. 100 @b{loop} - Internal; - @b{end} @b{loop}; -@b{end} Pooloc1; -@end smallexample +Do not look for sources in the system default directory. +@end table -@noindent -The @code{System.Pool_Size} package implements the Stack_Bounded_Pool used when -@code{Storage_Size} is specified for an access type. -The whole storage for the pool is -allocated at once, usually on the stack at the point where the access type is -elaborated. It is automatically reclaimed when exiting the scope where the -access type is defined. This package is not intended to be used directly by the -user and it is implicitly used for each such declaration: +@geindex -nostdlib (gnatfind) -@smallexample @c ada - @b{type} T1 @b{is} @b{access} Something; - @b{for} T1'Storage_Size @b{use} 10_000; -@end smallexample -@node The GNAT Debug Pool Facility -@section The GNAT Debug Pool Facility -@findex Debug Pool -@cindex storage, pool, memory corruption +@table @asis -@noindent -The use of unchecked deallocation and unchecked conversion can easily -lead to incorrect memory references. The problems generated by such -references are usually difficult to tackle because the symptoms can be -very remote from the origin of the problem. In such cases, it is -very helpful to detect the problem as early as possible. This is the -purpose of the Storage Pool provided by @code{GNAT.Debug_Pools}. +@item @code{nostdlib} -In order to use the GNAT specific debugging pool, the user must -associate a debug pool object with each of the access types that may be -related to suspected memory problems. See Ada Reference Manual 13.11. -@smallexample @c ada -@b{type} Ptr @b{is} @b{access} Some_Type; -Pool : GNAT.Debug_Pools.Debug_Pool; -@b{for} Ptr'Storage_Pool @b{use} Pool; -@end smallexample +Do not look for library files in the system default directory. +@end table -@noindent -@code{GNAT.Debug_Pools} is derived from a GNAT-specific kind of -pool: the @code{Checked_Pool}. Such pools, like standard Ada storage pools, -allow the user to redefine allocation and deallocation strategies. They -also provide a checkpoint for each dereference, through the use of -the primitive operation @code{Dereference} which is implicitly called at -each dereference of an access value. +@geindex --ext (gnatfind) -Once an access type has been associated with a debug pool, operations on -values of the type may raise four distinct exceptions, -which correspond to four potential kinds of memory corruption: -@itemize @bullet -@item -@code{GNAT.Debug_Pools.Accessing_Not_Allocated_Storage} -@item -@code{GNAT.Debug_Pools.Accessing_Deallocated_Storage} -@item -@code{GNAT.Debug_Pools.Freeing_Not_Allocated_Storage} -@item -@code{GNAT.Debug_Pools.Freeing_Deallocated_Storage } -@end itemize -@noindent -For types associated with a Debug_Pool, dynamic allocation is performed using -the standard GNAT allocation routine. References to all allocated chunks of -memory are kept in an internal dictionary. Several deallocation strategies are -provided, whereupon the user can choose to release the memory to the system, -keep it allocated for further invalid access checks, or fill it with an easily -recognizable pattern for debug sessions. The memory pattern is the old IBM -hexadecimal convention: @code{16#DEADBEEF#}. +@table @asis -See the documentation in the file g-debpoo.ads for more information on the -various strategies. +@item @code{-ext=@emph{extension}} -Upon each dereference, a check is made that the access value denotes a -properly allocated memory location. Here is a complete example of use of -@code{Debug_Pools}, that includes typical instances of memory corruption: -@smallexample @c ada -@iftex -@leftskip=0cm -@end iftex -@b{with} Gnat.Io; @b{use} Gnat.Io; -@b{with} Unchecked_Deallocation; -@b{with} Unchecked_Conversion; -@b{with} GNAT.Debug_Pools; -@b{with} System.Storage_Elements; -@b{with} Ada.Exceptions; @b{use} Ada.Exceptions; -@b{procedure} Debug_Pool_Test @b{is} - - @b{type} T @b{is} @b{access} Integer; - @b{type} U @b{is} @b{access} @b{all} T; +Specify an alternate ali file extension. The default is @cite{ali} and other +extensions (e.g. @cite{gli} for C/C++ sources when using @emph{-fdump-xref}) +may be specified via this switch. Note that if this switch overrides the +default, which means that only the new extension will be considered. +@end table - P : GNAT.Debug_Pools.Debug_Pool; - @b{for} T'Storage_Pool @b{use} P; +@geindex --RTS (gnatfind) - @b{procedure} Free @b{is} @b{new} Unchecked_Deallocation (Integer, T); - @b{function} UC @b{is} @b{new} Unchecked_Conversion (U, T); - A, B : @b{aliased} T; - @b{procedure} Info @b{is} @b{new} GNAT.Debug_Pools.Print_Info(Put_Line); +@table @asis -@b{begin} - Info (P); - A := @b{new} Integer; - B := @b{new} Integer; - B := A; - Info (P); - Free (A); - @b{begin} - Put_Line (Integer'Image(B.@b{all})); - @b{exception} - @b{when} E : @b{others} => Put_Line ("raised: " & Exception_Name (E)); - @b{end}; - @b{begin} - Free (B); - @b{exception} - @b{when} E : @b{others} => Put_Line ("raised: " & Exception_Name (E)); - @b{end}; - B := UC(A'Access); - @b{begin} - Put_Line (Integer'Image(B.@b{all})); - @b{exception} - @b{when} E : @b{others} => Put_Line ("raised: " & Exception_Name (E)); - @b{end}; - @b{begin} - Free (B); - @b{exception} - @b{when} E : @b{others} => Put_Line ("raised: " & Exception_Name (E)); - @b{end}; - Info (P); -@b{end} Debug_Pool_Test; -@end smallexample +@item @code{-RTS=@emph{rts-path}} -@noindent -The debug pool mechanism provides the following precise diagnostics on the -execution of this erroneous program: -@smallexample -Debug Pool info: - Total allocated bytes : 0 - Total deallocated bytes : 0 - Current Water Mark: 0 - High Water Mark: 0 +Specifies the default location of the runtime library. Same meaning as the +equivalent @emph{gnatmake} flag (@ref{df,,Switches for gnatmake}). +@end table -Debug Pool info: - Total allocated bytes : 8 - Total deallocated bytes : 0 - Current Water Mark: 8 - High Water Mark: 8 +@geindex -d (gnatfind) -raised: GNAT.DEBUG_POOLS.ACCESSING_DEALLOCATED_STORAGE -raised: GNAT.DEBUG_POOLS.FREEING_DEALLOCATED_STORAGE -raised: GNAT.DEBUG_POOLS.ACCESSING_NOT_ALLOCATED_STORAGE -raised: GNAT.DEBUG_POOLS.FREEING_NOT_ALLOCATED_STORAGE -Debug Pool info: - Total allocated bytes : 8 - Total deallocated bytes : 4 - Current Water Mark: 4 - High Water Mark: 8 -@end smallexample - -@ifclear FSFEDITION -@node The gnatmem Tool -@section The @command{gnatmem} Tool -@findex gnatmem - -@noindent -The @code{gnatmem} utility monitors dynamic allocation and -deallocation activity in a program, and displays information about -incorrect deallocations and possible sources of memory leaks. -It is designed to work in association with a static runtime library -only and in this context provides three types of information: -@itemize @bullet -@item -General information concerning memory management, such as the total -number of allocations and deallocations, the amount of allocated -memory and the high water mark, i.e.@: the largest amount of allocated -memory in the course of program execution. -@item -Backtraces for all incorrect deallocations, that is to say deallocations -which do not correspond to a valid allocation. +@table @asis -@item -Information on each allocation that is potentially the origin of a memory -leak. -@end itemize +@item @code{d} -@menu -* Running gnatmem:: -* Switches for gnatmem:: -* Example of gnatmem Usage:: -@end menu +If this switch is set, then @cite{gnatfind} will output the parent type +reference for each matching derived types. +@end table -@node Running gnatmem -@subsection Running @code{gnatmem} - -@noindent -@code{gnatmem} makes use of the output created by the special version of -allocation and deallocation routines that record call information. This allows -it to obtain accurate dynamic memory usage history at a minimal cost to the -execution speed. Note however, that @code{gnatmem} is not supported on all -platforms (currently, it is supported on AIX, HP-UX, GNU/Linux, Solaris and -Windows NT/2000/XP (x86). - -@noindent -The @code{gnatmem} command has the form - -@smallexample -@c $ gnatmem @ovar{switches} user_program -@c Expanding @ovar macro inline (explanation in macro def comments) - $ gnatmem @r{[}@var{switches}@r{]} @var{user_program} -@end smallexample - -@noindent -The program must have been linked with the instrumented version of the -allocation and deallocation routines. This is done by linking with the -@file{libgmem.a} library. For correct symbolic backtrace information, -the user program should be compiled with debugging options -(see @ref{Switches for gcc}). For example to build @file{my_program}: - -@smallexample -$ gnatmake -g my_program -largs -lgmem -@end smallexample - -@noindent -As library @file{libgmem.a} contains an alternate body for package -@code{System.Memory}, @file{s-memory.adb} should not be compiled and linked -when an executable is linked with library @file{libgmem.a}. It is then not -recommended to use @command{gnatmake} with switch @option{-a}. - -@noindent -When @file{my_program} is executed, the file @file{gmem.out} is produced. -This file contains information about all allocations and deallocations -performed by the program. It is produced by the instrumented allocations and -deallocations routines and will be used by @code{gnatmem}. - -In order to produce symbolic backtrace information for allocations and -deallocations performed by the GNAT run-time library, you need to use a -version of that library that has been compiled with the @option{-g} switch -(see @ref{Rebuilding the GNAT Run-Time Library}). - -Gnatmem must be supplied with the @file{gmem.out} file and the executable to -examine. If the location of @file{gmem.out} file was not explicitly supplied by -@option{-i} switch, gnatmem will assume that this file can be found in the -current directory. For example, after you have executed @file{my_program}, -@file{gmem.out} can be analyzed by @code{gnatmem} using the command: - -@smallexample -$ gnatmem my_program -@end smallexample - -@noindent -This will produce the output with the following format: - -*************** debut cc -@smallexample -$ gnatmem my_program - -Global information ------------------- - Total number of allocations : 45 - Total number of deallocations : 6 - Final Water Mark (non freed mem) : 11.29 Kilobytes - High Water Mark : 11.40 Kilobytes - -. -. -. -Allocation Root # 2 -------------------- - Number of non freed allocations : 11 - Final Water Mark (non freed mem) : 1.16 Kilobytes - High Water Mark : 1.27 Kilobytes - Backtrace : - my_program.adb:23 my_program.alloc -. -. -. -@end smallexample - -The first block of output gives general information. In this case, the -Ada construct ``@code{@b{new}}'' was executed 45 times, and only 6 calls to an -Unchecked_Deallocation routine occurred. - -@noindent -Subsequent paragraphs display information on all allocation roots. -An allocation root is a specific point in the execution of the program -that generates some dynamic allocation, such as a ``@code{@b{new}}'' -construct. This root is represented by an execution backtrace (or subprogram -call stack). By default the backtrace depth for allocations roots is 1, so -that a root corresponds exactly to a source location. The backtrace can -be made deeper, to make the root more specific. - -@node Switches for gnatmem -@subsection Switches for @code{gnatmem} - -@noindent -@code{gnatmem} recognizes the following switches: - -@table @option - -@item -q -@cindex @option{-q} (@code{gnatmem}) -Quiet. Gives the minimum output needed to identify the origin of the -memory leaks. Omits statistical information. - -@item @var{N} -@cindex @var{N} (@code{gnatmem}) -N is an integer literal (usually between 1 and 10) which controls the -depth of the backtraces defining allocation root. The default value for -N is 1. The deeper the backtrace, the more precise the localization of -the root. Note that the total number of roots can depend on this -parameter. This parameter must be specified @emph{before} the name of the -executable to be analyzed, to avoid ambiguity. - -@item -b n -@cindex @option{-b} (@code{gnatmem}) -This switch has the same effect as just depth parameter. - -@item -i @var{file} -@cindex @option{-i} (@code{gnatmem}) -Do the @code{gnatmem} processing starting from @file{file}, rather than -@file{gmem.out} in the current directory. - -@item -m n -@cindex @option{-m} (@code{gnatmem}) -This switch causes @code{gnatmem} to mask the allocation roots that have less -than n leaks. The default value is 1. Specifying the value of 0 will allow -examination of even the roots that did not result in leaks. - -@item -s order -@cindex @option{-s} (@code{gnatmem}) -This switch causes @code{gnatmem} to sort the allocation roots according to the -specified order of sort criteria, each identified by a single letter. The -currently supported criteria are @code{n, h, w} standing respectively for -number of unfreed allocations, high watermark, and final watermark -corresponding to a specific root. The default order is @code{nwh}. - -@item -t -@cindex @option{-t} (@code{gnatmem}) -This switch causes memory allocated size to be always output in bytes. -Default @code{gnatmem} behavior is to show memory sizes less then 1 kilobyte -in bytes, from 1 kilobyte till 1 megabyte in kilobytes and the rest in -megabytes. - -@end table - -@node Example of gnatmem Usage -@subsection Example of @code{gnatmem} Usage - -@noindent -The following example shows the use of @code{gnatmem} -on a simple memory-leaking program. -Suppose that we have the following Ada program: - -@smallexample @c ada -@group -@cartouche -@b{with} Unchecked_Deallocation; -@b{procedure} Test_Gm @b{is} - - @b{type} T @b{is} @b{array} (1..1000) @b{of} Integer; - @b{type} Ptr @b{is} @b{access} T; - @b{procedure} Free @b{is} @b{new} Unchecked_Deallocation (T, Ptr); - A : Ptr; - - @b{procedure} My_Alloc @b{is} - @b{begin} - A := @b{new} T; - @b{end} My_Alloc; - - @b{procedure} My_DeAlloc @b{is} - B : Ptr := A; - @b{begin} - Free (B); - @b{end} My_DeAlloc; - -@b{begin} - My_Alloc; - @b{for} I @b{in} 1 .. 5 @b{loop} - @b{for} J @b{in} I .. 5 @b{loop} - My_Alloc; - @b{end} @b{loop}; - My_Dealloc; - @b{end} @b{loop}; -@b{end}; -@end cartouche -@end group -@end smallexample - -@noindent -The program needs to be compiled with debugging option and linked with -@code{gmem} library: - -@smallexample -$ gnatmake -g test_gm -largs -lgmem -@end smallexample - -@noindent -Then we execute the program as usual: - -@smallexample -$ test_gm -@end smallexample - -@noindent -Then @code{gnatmem} is invoked simply with -@smallexample -$ gnatmem test_gm -@end smallexample - -@noindent -which produces the following output (result may vary on different platforms): - -@smallexample -Global information ------------------- - Total number of allocations : 18 - Total number of deallocations : 5 - Final Water Mark (non freed mem) : 53.00 Kilobytes - High Water Mark : 56.90 Kilobytes - -Allocation Root # 1 -------------------- - Number of non freed allocations : 11 - Final Water Mark (non freed mem) : 42.97 Kilobytes - High Water Mark : 46.88 Kilobytes - Backtrace : - test_gm.adb:11 test_gm.my_alloc - -Allocation Root # 2 -------------------- - Number of non freed allocations : 1 - Final Water Mark (non freed mem) : 10.02 Kilobytes - High Water Mark : 10.02 Kilobytes - Backtrace : - s-secsta.adb:81 system.secondary_stack.ss_init - -Allocation Root # 3 -------------------- - Number of non freed allocations : 1 - Final Water Mark (non freed mem) : 12 Bytes - High Water Mark : 12 Bytes - Backtrace : - s-secsta.adb:181 system.secondary_stack.ss_init -@end smallexample - -@noindent -Note that the GNAT run time contains itself a certain number of -allocations that have no corresponding deallocation, -as shown here for root #2 and root -#3. This is a normal behavior when the number of non-freed allocations -is one, it allocates dynamic data structures that the run time needs for -the complete lifetime of the program. Note also that there is only one -allocation root in the user program with a single line back trace: -test_gm.adb:11 test_gm.my_alloc, whereas a careful analysis of the -program shows that 'My_Alloc' is called at 2 different points in the -source (line 21 and line 24). If those two allocation roots need to be -distinguished, the backtrace depth parameter can be used: - -@smallexample -$ gnatmem 3 test_gm -@end smallexample - -@noindent -which will give the following output: - -@smallexample -Global information ------------------- - Total number of allocations : 18 - Total number of deallocations : 5 - Final Water Mark (non freed mem) : 53.00 Kilobytes - High Water Mark : 56.90 Kilobytes - -Allocation Root # 1 -------------------- - Number of non freed allocations : 10 - Final Water Mark (non freed mem) : 39.06 Kilobytes - High Water Mark : 42.97 Kilobytes - Backtrace : - test_gm.adb:11 test_gm.my_alloc - test_gm.adb:24 test_gm - b_test_gm.c:52 main - -Allocation Root # 2 -------------------- - Number of non freed allocations : 1 - Final Water Mark (non freed mem) : 10.02 Kilobytes - High Water Mark : 10.02 Kilobytes - Backtrace : - s-secsta.adb:81 system.secondary_stack.ss_init - s-secsta.adb:283 <system__secondary_stack___elabb> - b_test_gm.c:33 adainit - -Allocation Root # 3 -------------------- - Number of non freed allocations : 1 - Final Water Mark (non freed mem) : 3.91 Kilobytes - High Water Mark : 3.91 Kilobytes - Backtrace : - test_gm.adb:11 test_gm.my_alloc - test_gm.adb:21 test_gm - b_test_gm.c:52 main - -Allocation Root # 4 -------------------- - Number of non freed allocations : 1 - Final Water Mark (non freed mem) : 12 Bytes - High Water Mark : 12 Bytes - Backtrace : - s-secsta.adb:181 system.secondary_stack.ss_init - s-secsta.adb:283 <system__secondary_stack___elabb> - b_test_gm.c:33 adainit -@end smallexample - -@noindent -The allocation root #1 of the first example has been split in 2 roots #1 -and #3 thanks to the more precise associated backtrace. -@end ifclear - -@node Stack Related Facilities -@chapter Stack Related Facilities - -@noindent -This chapter describes some useful tools associated with stack -checking and analysis. In -particular, it deals with dynamic and static stack usage measurements. +@geindex -e (gnatfind) -@menu -* Stack Overflow Checking:: -* Static Stack Usage Analysis:: -* Dynamic Stack Usage Analysis:: -@end menu -@node Stack Overflow Checking -@section Stack Overflow Checking -@cindex Stack Overflow Checking -@cindex -fstack-check +@table @asis -@noindent -For most operating systems, @command{gcc} does not perform stack overflow -checking by default. This means that if the main environment task or -some other task exceeds the available stack space, then unpredictable -behavior will occur. Most native systems offer some level of protection by -adding a guard page at the end of each task stack. This mechanism is usually -not enough for dealing properly with stack overflow situations because -a large local variable could ``jump'' above the guard page. -Furthermore, when the -guard page is hit, there may not be any space left on the stack for executing -the exception propagation code. Enabling stack checking avoids -such situations. +@item @code{e} -To activate stack checking, compile all units with the gcc option -@option{-fstack-check}. For example: +By default, @cite{gnatfind} accept the simple regular expression set for +@cite{pattern}. If this switch is set, then the pattern will be +considered as full Unix-style regular expression. +@end table -@smallexample -gcc -c -fstack-check package1.adb -@end smallexample +@geindex -f (gnatfind) -@noindent -Units compiled with this option will generate extra instructions to check -that any use of the stack (for procedure calls or for declaring local -variables in declare blocks) does not exceed the available stack space. -If the space is exceeded, then a @code{Storage_Error} exception is raised. -For declared tasks, the stack size is controlled by the size -given in an applicable @code{Storage_Size} pragma or by the value specified -at bind time with @option{-d} (@pxref{Switches for gnatbind}) or is set to -the default size as defined in the GNAT runtime otherwise. +@table @asis -For the environment task, the stack size depends on -system defaults and is unknown to the compiler. Stack checking -may still work correctly if a fixed -size stack is allocated, but this cannot be guaranteed. -To ensure that a clean exception is signalled for stack -overflow, set the environment variable -@env{GNAT_STACK_LIMIT} to indicate the maximum -stack area that can be used, as in: -@cindex GNAT_STACK_LIMIT +@item @code{f} -@smallexample -SET GNAT_STACK_LIMIT 1600 -@end smallexample +If this switch is set, the output file names will be preceded by their +directory (if the file was found in the search path). If this switch is +not set, the directory will not be printed. +@end table -@noindent -The limit is given in kilobytes, so the above declaration would -set the stack limit of the environment task to 1.6 megabytes. -Note that the only purpose of this usage is to limit the amount -of stack used by the environment task. If it is necessary to -increase the amount of stack for the environment task, then this -is an operating systems issue, and must be addressed with the -appropriate operating systems commands. +@geindex -g (gnatfind) -@node Static Stack Usage Analysis -@section Static Stack Usage Analysis -@cindex Static Stack Usage Analysis -@cindex -fstack-usage -@noindent -A unit compiled with @option{-fstack-usage} will generate an extra file -that specifies -the maximum amount of stack used, on a per-function basis. -The file has the same -basename as the target object file with a @file{.su} extension. -Each line of this file is made up of three fields: +@table @asis -@itemize -@item -The name of the function. -@item -A number of bytes. -@item -One or more qualifiers: @code{static}, @code{dynamic}, @code{bounded}. -@end itemize +@item @code{g} -The second field corresponds to the size of the known part of the function -frame. +If this switch is set, information is output only for library-level +entities, ignoring local entities. The use of this switch may accelerate +@cite{gnatfind} and @cite{gnatxref}. +@end table -The qualifier @code{static} means that the function frame size -is purely static. -It usually means that all local variables have a static size. -In this case, the second field is a reliable measure of the function stack -utilization. +@geindex -IDIR (gnatfind) -The qualifier @code{dynamic} means that the function frame size is not static. -It happens mainly when some local variables have a dynamic size. When this -qualifier appears alone, the second field is not a reliable measure -of the function stack analysis. When it is qualified with @code{bounded}, it -means that the second field is a reliable maximum of the function stack -utilization. -A unit compiled with @option{-Wstack-usage} will issue a warning for each -subprogram whose stack usage might be larger than the specified amount of -bytes. The wording is in keeping with the qualifier documented above. +@table @asis -@node Dynamic Stack Usage Analysis -@section Dynamic Stack Usage Analysis +@item @code{I@emph{DIR}} -@noindent -It is possible to measure the maximum amount of stack used by a task, by -adding a switch to @command{gnatbind}, as: +Equivalent to @code{-aODIR -aIDIR}. +@end table -@smallexample -$ gnatbind -u0 file -@end smallexample +@geindex -pFILE (gnatfind) -@noindent -With this option, at each task termination, its stack usage is output on -@file{stderr}. -It is not always convenient to output the stack usage when the program -is still running. Hence, it is possible to delay this output until program -termination. for a given number of tasks specified as the argument of the -@option{-u} option. For instance: -@smallexample -$ gnatbind -u100 file -@end smallexample +@table @asis -@noindent -will buffer the stack usage information of the first 100 tasks to terminate and -output this info at program termination. Results are displayed in four -columns: +@item @code{p@emph{FILE}} -@noindent -Index | Task Name | Stack Size | Stack Usage +Specify a project file (@ref{b,,GNAT Project Manager}) to use. +By default, @cite{gnatxref} and @cite{gnatfind} will try to locate a +project file in the current directory. -@noindent -where: +If a project file is either specified or found by the tools, then the content +of the source directory and object directory lines are added as if they +had been specified respectively by @code{-aI} and +@code{-aO}. +@end table -@table @emph -@item Index -is a number associated with each task. +@geindex -r (gnatfind) -@item Task Name -is the name of the task analyzed. -@item Stack Size -is the maximum size for the stack. +@table @asis -@item Stack Usage -is the measure done by the stack analyzer. In order to prevent overflow, the stack -is not entirely analyzed, and it's not possible to know exactly how -much has actually been used. +@item @code{r} +By default, @cite{gnatfind} will output only the information about the +declaration, body or type completion of the entities. If this switch is +set, the @cite{gnatfind} will locate every reference to the entities in +the files specified on the command line (or in every file in the search +path if no file is given on the command line). @end table -@noindent -The environment task stack, e.g., the stack that contains the main unit, is -only processed when the environment variable GNAT_STACK_LIMIT is set. - -@noindent -The package @code{GNAT.Task_Stack_Usage} provides facilities to get -stack usage reports at run-time. See its body for the details. - -@ifclear FSFEDITION -@c ********************************* -@c * GNATCHECK * -@c ********************************* -@node Verifying Properties with gnatcheck -@chapter Verifying Properties with @command{gnatcheck} -@findex gnatcheck -@cindex @command{gnatcheck} - -@noindent -The @command{gnatcheck} tool is an ASIS-based utility that checks properties -of Ada source files according to a given set of semantic rules. -@cindex ASIS - -In order to check compliance with a given rule, @command{gnatcheck} has to -semantically analyze the Ada sources. -Therefore, checks can only be performed on -legal Ada units. Moreover, when a unit depends semantically upon units located -outside the current directory, the source search path has to be provided when -calling @command{gnatcheck}, either through a specified project file or -through @command{gnatcheck} switches. - -For full details, refer to @cite{GNATcheck Reference Manual} document. -@end ifclear - -@ifclear FSFEDITION -@c ********************************* -@node Creating Sample Bodies with gnatstub -@chapter Creating Sample Bodies with @command{gnatstub} -@findex gnatstub - -@noindent -@command{gnatstub} creates empty but compilable bodies -for library unit declarations and empty but compilable -subunit for body stubs. - -To create a body or a subunit, @command{gnatstub} invokes the Ada -compiler and generates and uses the ASIS tree for the input source; -thus the input must be legal Ada code, and the tool should have all the -information needed to compile the input source. To provide this information, -you may specify as a tool parameter the project file the input source belongs to -(or you may call @command{gnatstub} -through the @command{gnat} driver (see @ref{The GNAT Driver and -Project Files}). Another possibility is to specify the source search -path and needed configuration files in @option{-cargs} section of @command{gnatstub} -call, see the description of the @command{gnatstub} switches below. - -If the @command{gnatstub} argument source contains preprocessing directives -then the needed options should be provided to run preprocessor as a part of -the @command{gnatstub} call, and the generated body stub will correspond to -the preprocessed source. - -By default, all the program unit bodies generated by @code{gnatstub} -raise the predefined @code{Program_Error} exception, which will catch -accidental calls of generated stubs. This behavior can be changed with -option @option{--no-exception} (see below). +@geindex -s (gnatfind) -@menu -* Running gnatstub:: -* Switches for gnatstub:: -@end menu -@node Running gnatstub -@section Running @command{gnatstub} +@table @asis -@noindent -@command{gnatstub} has a command-line interface of the form: +@item @code{s} -@smallexample -@c $ gnatstub @ovar{switches} @var{filename} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatstub @r{[}@var{switches}@r{]} @var{filename} @r{[}-cargs @var{gcc_switches}@r{]} -@end smallexample +If this switch is set, then @cite{gnatfind} will output the content +of the Ada source file lines were the entity was found. +@end table -@noindent -where -@table @var -@item filename -is the name of the source file that contains a library unit declaration -for which a body must be created or a library unit body for which subunits -must be created for the body stubs declared in this body. -The file name may contain the path information. -If the name does not follow GNAT file naming conventions and a set -of seitches does not contain a project file that defines naming -conventions, the name of the body file must -be provided -explicitly as the value of the @option{-o@var{body-name}} option. -If the file name follows the GNAT file naming -conventions and the name of the body file is not provided, -@command{gnatstub} -takes the naming conventions for the generated source from the -project file provided as a parameter of @option{-P} switch if any, -or creates the name file to generate using the standard GNAT -naming conventions. - -@item @samp{@var{gcc_switches}} is a list of switches for -@command{gcc}. They will be passed on to all compiler invocations made by -@command{gnatstub} to generate the ASIS trees. Here you can provide -@option{-I} switches to form the source search path, -use the @option{-gnatec} switch to set the configuration file, -use the @option{-gnat05} switch if sources should be compiled in -Ada 2005 mode etc. - -@item switches -is an optional sequence of switches as described in the next section -@end table - -@node Switches for gnatstub -@section Switches for @command{gnatstub} - -@table @option -@c !sort! - -@item --version -@cindex @option{--version} @command{gnatstub} -Display Copyright and version, then exit disregarding all other options. +@geindex -t (gnatfind) -@item --help -@cindex @option{--help} @command{gnatstub} -Display usage, then exit disregarding all other options. -@item -P @var{file} -@cindex @option{-P} @command{gnatstub} -Indicates the name of the project file that describes the set of sources -to be processed. +@table @asis -@item -X@var{name}=@var{value} -@cindex @option{-X} @command{gnatstub} -Indicates that external variable @var{name} in the argument project -has the value @var{value}. Has no effect if no project is specified as -tool argument. +@item @code{t} -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gnatstub}) -Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). - -@item --subunits -@cindex @option{--subunits} (@command{gnatstub}) -Generate subunits for body stubs. If this switch is specified, -@command{gnatstub} expects a library unit body as an agrument file, -otherwise a library unit declaration is expected. If a body stub -already has a corresponding subunit, @command{gnatstub} does not -generate anything for it. - -@item -f -@cindex @option{-f} (@command{gnatstub}) -If the destination directory already contains a file with the name of the -body file -for the argument spec file, replace it with the generated body stub. -This switch cannot be used together with @option{--subunits}. - -@item -hs -@cindex @option{-hs} (@command{gnatstub}) -Put the comment header (i.e., all the comments preceding the -compilation unit) from the source of the library unit declaration -into the body stub. - -@item -hg -@cindex @option{-hg} (@command{gnatstub}) -Put a sample comment header into the body stub. - -@item --header-file=@var{filename} -@cindex @option{--header-file} (@command{gnatstub}) -Use the content of the file as the comment header for a generated body stub. - -@item -IDIR -@cindex @option{-IDIR} (@command{gnatstub}) -@itemx -I- -@cindex @option{-I-} (@command{gnatstub}) -These switches have the same meaning as in calls to -@command{gcc}. -They define the source search path in the call to -@command{gcc} issued -by @command{gnatstub} to compile an argument source file. - -@item -gnatec@var{PATH} -@cindex @option{-gnatec} (@command{gnatstub}) -This switch has the same meaning as in calls to @command{gcc}. -It defines the additional configuration file to be passed to the call to -@command{gcc} issued -by @command{gnatstub} to compile an argument source file. - -@item -gnatyM@var{n} -@cindex @option{-gnatyM} (@command{gnatstub}) -(@var{n} is a non-negative integer). Set the maximum line length that is -allowed in a source file. The default is 79. The maximum value that can be -specified is 32767. Note that in the special case of configuration -pragma files, the maximum is always 32767 regardless of whether or -not this switch appears. - -@item -gnaty@var{n} -@cindex @option{-gnaty} (@command{gnatstub}) -(@var{n} is a non-negative integer from 1 to 9). Set the indentation level in -the generated body sample to @var{n}. -The default indentation is 3. - -@item -gnatyo -@cindex @option{-gnatyo} (@command{gnatstub}) -Order local bodies alphabetically. (By default local bodies are ordered -in the same way as the corresponding local specs in the argument spec file.) - -@item -i@var{n} -@cindex @option{-i} (@command{gnatstub}) -Same as @option{-gnaty@var{n}} - -@item -k -@cindex @option{-k} (@command{gnatstub}) -Do not remove the tree file (i.e., the snapshot of the compiler internal -structures used by @command{gnatstub}) after creating the body stub. - -@item -l@var{n} -@cindex @option{-l} (@command{gnatstub}) -Same as @option{-gnatyM@var{n}} - -@item --no-exception -@cindex @option{--no-exception} (@command{gnatstub}) -Avoid raising PROGRAM_ERROR in the generated bodies of program unit stubs. -This is not always possible for function stubs. - -@item --no-local-header -@cindex @option{--no-local-header} (@command{gnatstub}) -Do not place local comment header with unit name before body stub for a -unit. +If this switch is set, then @cite{gnatfind} will output the type hierarchy for +the specified type. It act like -d option but recursively from parent +type to parent type. When this switch is set it is not possible to +specify more than one file. +@end table -@item -o @var{body-name} -@cindex @option{-o} (@command{gnatstub}) -Body file name. This should be set if the argument file name does not -follow -the GNAT file naming -conventions. If this switch is omitted the default name for the body will be -obtained -from the argument file name according to the GNAT file naming conventions. +All these switches may be in any order on the command line, and may even +appear after the file names. They need not be separated by spaces, thus +you can say @code{gnatxref -ag} instead of +@code{gnatxref -a -g}. -@item --dir=@var{dir-name} -@cindex @option{--dir} (@command{gnatstub}) -The path to the directory to place the generated files into. -If this switch is not set, the generated library unit body is -placed in the current directory, and generated sununits - -in the directory where the argument body is located. +As stated previously, gnatfind will search in every directory in the +search path. You can force it to look only in the current directory if +you specify @cite{*} at the end of the command line. -@item -W@var{e} -@cindex @option{-W} (@command{gnatstub}) -Specify the wide character encoding method for the output body file. -@var{e} is one of the following: +@node Project Files for gnatxref and gnatfind,Regular Expressions in gnatfind and gnatxref,gnatfind Switches,The Cross-Referencing Tools gnatxref and gnatfind +@anchor{gnat_ugn/gnat_utility_programs project-files-for-gnatxref-and-gnatfind}@anchor{1e2}@anchor{gnat_ugn/gnat_utility_programs id12}@anchor{1e3} +@subsection Project Files for @emph{gnatxref} and @emph{gnatfind} -@itemize @bullet -@item h -Hex encoding +Project files allow a programmer to specify how to compile its +application, where to find sources, etc. These files are used +primarily by GPS, but they can also be used +by the two tools @cite{gnatxref} and @cite{gnatfind}. -@item u -Upper half encoding +A project file name must end with @code{.gpr}. If a single one is +present in the current directory, then @cite{gnatxref} and @cite{gnatfind} will +extract the information from it. If multiple project files are found, none of +them is read, and you have to use the @code{-p} switch to specify the one +you want to use. -@item s -Shift/JIS encoding +The following lines can be included, even though most of them have default +values which can be used in most cases. +The lines can be entered in any order in the file. +Except for @code{src_dir} and @code{obj_dir}, you can only have one instance of +each line. If you have multiple instances, only the last one is taken into +account. -@item e -EUC encoding -@item 8 -UTF-8 encoding +@itemize * -@item b -Brackets encoding (default value) -@end itemize +@item -@item -q -@cindex @option{-q} (@command{gnatstub}) -Quiet mode: do not generate a confirmation when a body is -successfully created, and do not generate a message when a body is not -required for an -argument unit. - -@item -r -@cindex @option{-r} (@command{gnatstub}) -Reuse the tree file (if it exists) instead of creating it. Instead of -creating the tree file for the library unit declaration, @command{gnatstub} -tries to find it in the current directory and use it for creating -a body. If the tree file is not found, no body is created. This option -also implies @option{-k}, whether or not -the latter is set explicitly. - -@item -t -@cindex @option{-t} (@command{gnatstub}) -Overwrite the existing tree file. If the current directory already -contains the file which, according to the GNAT file naming rules should -be considered as a tree file for the argument source file, -@command{gnatstub} -will refuse to create the tree file needed to create a sample body -unless this option is set. - -@item -v -@cindex @option{-v} (@command{gnatstub}) -Verbose mode: generate version information. - -@end table -@end ifclear - -@ifclear FSFEDITION -@c ********************************* -@node Creating Unit Tests with gnattest -@chapter Creating Unit Tests with @command{gnattest} -@findex gnattest - -@noindent -@command{gnattest} is an ASIS-based utility that creates unit-test skeletons -as well as a test driver infrastructure (harness). @command{gnattest} creates -a skeleton for each visible subprogram in the packages under consideration when -they do not exist already. - -The user can choose to generate a single test driver -that will run all individual tests, or separate test drivers for each test. The -second option allows much greater flexibility in test execution environment, -allows to benefit from parallel tests execution to increase performance, and -provides stubbing support. - -@command{gnattest} also has a mode of operation where it acts as the test -aggregator when multiple test executables must be run, in particular when -the separate test drivers were generated. In this mode it handles individual -tests execution and upon completion reports the summary results of the test -run. - -In order to process source files from a project, @command{gnattest} has to -semantically analyze the sources. Therefore, test skeletons can only be -generated for legal Ada units. If a unit is dependent on other units, -those units should be among the source files of the project or of other projects -imported by this one. - -Generated skeletons and harnesses are based on the AUnit testing framework. -AUnit is an Ada adaptation of the xxxUnit testing frameworks, similar to JUnit -for Java or CppUnit for C++. While it is advised that gnattest users read -the AUnit manual, deep knowledge of AUnit is not necessary for using gnattest. -For correct operation of @command{gnattest}, AUnit should be installed and -aunit.gpr must be on the project path. This happens automatically when Aunit -is installed at its default location. +@table @asis -@menu -* Running gnattest:: -* Switches for gnattest in framework generation mode:: -* Switches for gnattest in tests execution mode:: -* Project Attributes for gnattest:: -* Simple Example:: -* Setting Up and Tearing Down the Testing Environment:: -* Regenerating Tests:: -* Default Test Behavior:: -* Testing Primitive Operations of Tagged Types:: -* Testing Inheritance:: -* Tagged Types Substitutability Testing:: -* Testing with Contracts:: -* Additional Tests:: -* Individual Test Drivers:: -* Stubbing:: -* Putting Tests under Version Control:: -* Support for other platforms/run-times:: -* Current Limitations:: -@end menu +@item @emph{src_dir=DIR} -@node Running gnattest -@section Running @command{gnattest} +[default: @cite{"./"}]. +Specifies a directory where to look for source files. Multiple @cite{src_dir} +lines can be specified and they will be searched in the order they +are specified. +@end table -@noindent -@b{In the framework generation mode}, @command{gnattest} has a command-line -interface of the form +@item -@smallexample -@c $ gnattest @var{-Pprojname} @ovar{switches} @ovar{filename} @ovar{directory} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnattest @var{-Pprojname} @r{[}@var{--harness-dir=dirname}@r{]} @r{[}@var{switches}@r{]} @r{[}@var{filename}@r{]} @r{[}-cargs @var{gcc_switches}@r{]} -@end smallexample +@table @asis -@noindent -where -@table @var +@item @emph{obj_dir=DIR} -@item -Pprojname -specifies the project defining the location of source files. When no -file names are provided on the command line, all sources in the project -are used as input. This switch is required. +[default: @cite{"./"}]. +Specifies a directory where to look for object and library files. Multiple +@cite{obj_dir} lines can be specified, and they will be searched in the order +they are specified +@end table -@item filename -is the name of the source file containing the library unit package declaration -for which a test package will be created. The file name may be given with a -path. +@item -@item @samp{@var{gcc_switches}} -is a list of switches for -@command{gcc}. These switches will be passed on to all compiler invocations -made by @command{gnattest} to generate a set of ASIS trees. Here you can provide -@option{-I} switches to form the source search path, -use the @option{-gnatec} switch to set the configuration file, -use the @option{-gnat05} switch if sources should be compiled in -Ada 2005 mode, etc. +@table @asis -@item switches -is an optional sequence of switches as described in the next section. +@item @emph{comp_opt=SWITCHES} +[default: @cite{""}]. +Creates a variable which can be referred to subsequently by using +the @cite{$@{comp_opt@}} notation. This is intended to store the default +switches given to @emph{gnatmake} and @emph{gcc}. @end table -@command{gnattest} results can be found in two different places. +@item -@itemize @bullet -@item automatic harness: -the harness code, which is located by default in "gnattest/harness" directory -that is created in the object directory of corresponding project file. All of -this code is generated completely automatically and can be destroyed and -regenerated at will. It is not recommended to modify this code manually, since -it could easily be overridden by mistake. The entry point in the harness code is -the project file named @command{test_driver.gpr}. Tests can be compiled and run -using a command such as: - -@smallexample -gnatmake -P<harness-dir>/test_driver -test_runner -@end smallexample +@table @asis -Note that you might need to specify the necessary values of scenario variables -when you are not using the AUnit defaults. +@item @emph{bind_opt=SWITCHES} -@item actual unit test skeletons: -a test skeleton for each visible subprogram is created in a separate file, if it -doesn't exist already. By default, those separate test files are located in a -"gnattest/tests" directory that is created in the object directory of -corresponding project file. For example, if a source file my_unit.ads in -directory src contains a visible subprogram Proc, then the corresponding unit -test will be found in file src/tests/my_unit-test_data-tests.adb and will be -called Test_Proc_<code>. <code> is a signature encoding used to differentiate -test names in case of overloading. +[default: @cite{""}]. +Creates a variable which can be referred to subsequently by using +the @code{$@emph{bind_opt}} notation. This is intended to store the default +switches given to @emph{gnatbind}. +@end table -Note that if the project already has both my_unit.ads and my_unit-test_data.ads, -this will cause a name conflict with the generated test package. -@end itemize +@item +@table @asis -@noindent -@b{In the tests execution mode mode}, @command{gnattest} has a command-line -interface of the form +@item @emph{link_opt=SWITCHES} -@smallexample -@c $ gnattest @var{-Pprojname} @ovar{switches} @ovar{filename} @ovar{directory} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnattest @var{test_drivers.list} @r{[}@var{switches}@r{]} -@end smallexample +[default: @cite{""}]. +Creates a variable which can be referred to subsequently by using +the @code{$@emph{link_opt}} notation. This is intended to store the default +switches given to @emph{gnatlink}. +@end table -@noindent -where -@table @var +@item -@item test_drivers.list -is the name of the text file containing the list of executables to treat as -test drivers. This file is automatically generated by gnattest, but can be -hand-edited to add or remove tests. This switch is required. +@table @asis -@item switches -is an optional sequence of switches as described below. +@item @emph{main=EXECUTABLE} +[default: @cite{""}]. +Specifies the name of the executable for the application. This variable can +be referred to in the following lines by using the @code{@emph{$@{main}} notation. @end table +@item -@node Switches for gnattest in framework generation mode -@section Switches for @command{gnattest} in framework generation mode - -@table @option -@c !sort! +@table @asis -@item -q -@cindex @option{-q} (@command{gnattest}) -Quiet mode: suppresses noncritical output messages. +@item @emph{comp_cmd=COMMAND} -@item -v -@cindex @option{-v} (@command{gnattest}) -Verbose mode: generates version information if specified by itself on the -command line. If specified via GNATtest_Switches, produces output -about the execution of the tool. +[default: @cite{"gcc -c -I$@{src_dir@} -g -gnatq"}]. +Specifies the command used to compile a single file in the application. +@end table -@item -r -@cindex @option{-r} (@command{gnattest}) -Recursively considers all sources from all projects. +@item +@table @asis -@item -X@var{name=value} -@cindex @option{-X} (@command{gnattest}) -Indicate that external variable @var{name} has the value @var{value}. +@item @emph{make_cmd=COMMAND} -@item --RTS=@var{rts-path} -@cindex @option{--RTS} (@command{gnattest}) -Specifies the default location of the runtime library. Same meaning as the -equivalent @command{gnatmake} flag (@pxref{Switches for gnatmake}). - - -@item --additional-tests=@var{projname} -@cindex @option{--additional-tests} (@command{gnattest}) -Sources described in @var{projname} are considered potential additional -manual tests to be added to the test suite. - -@item --harness-only -@cindex @option{--harness-only} (@command{gnattest}) -When this option is given, @command{gnattest} creates a harness for all -sources, treating them as test packages. - -@item --separate-drivers -@cindex @option{--separate-drivers} (@command{gnattest}) -Generates a separate test driver for each test, rather than a single -executable incorporating all tests. - -@item --stub -@cindex @option{--stub} (@command{gnattest}) -Generates the testing framework that uses subsystem stubbing to isolate the -code under test. - - -@item --harness-dir=@var{dirname} -@cindex @option{--harness-dir} (@command{gnattest}) -Specifies the directory that will hold the harness packages and project file -for the test driver. If the @var{dirname} is a relative path, it is considered -relative to the object directory of the project file. - -@item --tests-dir=@var{dirname} -@cindex @option{--tests-dir} (@command{gnattest}) -All test packages are placed in the @var{dirname} directory. -If the @var{dirname} is a relative path, it is considered relative to the object -directory of the project file. When all sources from all projects are taken -recursively from all projects, @var{dirname} directories are created for each -project in their object directories and test packages are placed accordingly. - -@item --subdir=@var{dirname} -@cindex @option{--subdir} (@command{gnattest}) -Test packages are placed in a subdirectory of the corresponding source -directory, with the name @var{dirname}. Thus, each set of unit tests is located -in a subdirectory of the code under test. If the sources are in separate -directories, each source directory has a test subdirectory named @var{dirname}. - -@item --tests-root=@var{dirname} -@cindex @option{--tests-root} (@command{gnattest}) -The hierarchy of source directories, if any, is recreated in the @var{dirname} -directory, with test packages placed in directories corresponding to those -of the sources. -If the @var{dirname} is a relative path, it is considered relative to the object -directory of the project file. When projects are considered recursively, -directory hierarchies of tested sources are -recreated for each project in their object directories and test packages are -placed accordingly. - -@item --stubs-dir=@var{dirname} -@cindex @option{--stubs-dir} (@command{gnattest}) -The hierarchy of directories containing stubbed units is recreated in -the @var{dirname} directory, with stubs placed in directories corresponding to -projects they are derived from. -If the @var{dirname} is a relative path, it is considered relative to the object -directory of the project file. When projects are considered recursively, -directory hierarchies of stubs are -recreated for each project in their object directories and test packages are -placed accordingly. - - -@item --validate-type-extensions -@cindex @option{--validate-type-extensions} (@command{gnattest}) -Enables substitution check: run all tests from all parents in order -to check substitutability in accordance with LSP. - -@item --skeleton-default=@var{val} -@cindex @option{--skeleton-default} (@command{gnattest}) -Specifies the default behavior of generated skeletons. @var{val} can be either -"fail" or "pass", "fail" being the default. - -@item --passed-tests=@var{val} -@cindex @option{--passed-tests} (@command{gnattest}) -Specifies whether or not passed tests should be shown. @var{val} can be either -"show" or "hide", "show" being the default. - -@item --exit-status=@var{val} -@cindex @option{--exit-status} (@command{gnattest}) -Specifies whether or not generated test driver should return failure exit -status if at least one test fails or crashes. @var{val} can be either -"on" or "off", "off" being the default. - -@item --omit-sloc -@cindex @option{--omit-sloc} (@command{gnattest}) -Suppresses comment line containing file name and line number of corresponding -subprograms in test skeletons. - -@item --no-command-line -@cindex @option{--no-command-line} (@command{gnattest}) -Don't add command line support to test driver. Note that regardless of this -switch, @command{gnattest} will automatically refrain from adding command -line support if it detects that the selected run-time doesn't provide -this capability. - - -@item --separates -@cindex @option{--separates} (@command{gnattest}) -Bodies of all test routines are generated as separates. Note that this mode is -kept for compatibility reasons only and it is not advised to use it due to -possible problems with hash in names of test skeletons when using an -inconsistent casing. Separate test skeletons can be incorporated to monolith -test package with improved hash being used by using @option{--transition} -switch. +[default: @cite{"gnatmake $@{main@} -aI$@{src_dir@} -aO$@{obj_dir@} -g -gnatq -cargs $@{comp_opt@} -bargs $@{bind_opt@} -largs $@{link_opt@}"}]. +Specifies the command used to recompile the whole application. +@end table +@item -@item --transition -@cindex @option{--transition} (@command{gnattest}) -This allows transition from separate test routines to monolith test packages. -All matching test routines are overwritten with contents of corresponding -separates. Note that if separate test routines had any manually added with -clauses they will be moved to the test package body as is and have to be moved -by hand. +@table @asis -@item --test-duration -@cindex @option{--test-duration} (@command{gnattest}) -Adds time measurements for each test in generated test driver. +@item @emph{run_cmd=COMMAND} +[default: @cite{"$@{main@}"}]. +Specifies the command used to run the application. @end table -@option{--tests_root}, @option{--subdir} and @option{--tests-dir} switches are -mutually exclusive. +@item +@table @asis -@node Switches for gnattest in tests execution mode -@section Switches for @command{gnattest} in tests execution mode - -@table @option -@c !sort! +@item @emph{debug_cmd=COMMAND} -@item --passed-tests=@var{val} -@cindex @option{--passed-tests} (@command{gnattest}) -Specifies whether or not passed tests should be shown. @var{val} can be either -"show" or "hide", "show" being the default. +[default: @cite{"gdb $@{main@}"}]. +Specifies the command used to debug the application +@end table +@end itemize -@item --queues=@var{n}, -j@var{n} -@cindex @option{--queues} (@command{gnattest}) -@cindex @option{-j} (@command{gnattest}) -Runs @var{n} tests in parallel (default is 1). +@emph{gnatxref} and @emph{gnatfind} only take into account the +@cite{src_dir} and @cite{obj_dir} lines, and ignore the others. -@end table +@node Regular Expressions in gnatfind and gnatxref,Examples of gnatxref Usage,Project Files for gnatxref and gnatfind,The Cross-Referencing Tools gnatxref and gnatfind +@anchor{gnat_ugn/gnat_utility_programs id13}@anchor{1e4}@anchor{gnat_ugn/gnat_utility_programs regular-expressions-in-gnatfind-and-gnatxref}@anchor{1e0} +@subsection Regular Expressions in @cite{gnatfind} and @cite{gnatxref} -@node Project Attributes for gnattest -@section Project Attributes for @command{gnattest} +As specified in the section about @emph{gnatfind}, the pattern can be a +regular expression. Two kinds of regular expressions +are recognized: -@noindent -Most of the command-line options can also be passed to the tool by adding -special attributes to the project file. Those attributes should be put in -package gnattest. Here is the list of attributes: +@itemize * -@itemize @bullet +@item -@item Tests_Root -is used to select the same output mode as with the --tests-root option. -This attribute cannot be used together with Subdir or Tests_Dir. +@table @asis -@item Subdir -is used to select the same output mode as with the --subdir option. -This attribute cannot be used together with Tests_Root or Tests_Dir. +@item @emph{Globbing pattern} -@item Tests_Dir -is used to select the same output mode as with the --tests-dir option. -This attribute cannot be used together with Subdir or Tests_Root. +These are the most common regular expression. They are the same as are +generally used in a Unix shell command line, or in a DOS session. -@item Harness_Dir -is used to specify the directory in which to place harness packages and project -file for the test driver, otherwise specified by --harness-dir. +Here is a more formal grammar: -@item Additional_Tests -is used to specify the project file, otherwise given by ---additional-tests switch. +@example +regexp ::= term +term ::= elmt -- matches elmt +term ::= elmt elmt -- concatenation (elmt then elmt) +term ::= * -- any string of 0 or more characters +term ::= ? -- matches any character +term ::= [char @{char@}] -- matches any character listed +term ::= [char - char] -- matches any character in range +@end example +@end table -@item Skeletons_Default -is used to specify the default behaviour of test skeletons, otherwise -specified by --skeleton-default option. The value of this attribute -should be either "pass" or "fail". +@item -@end itemize +@table @asis -Each of those attributes can be overridden from the command line if needed. -Other @command{gnattest} switches can also be passed via the project -file as an attribute list called GNATtest_Switches. +@item @emph{Full regular expression} -@node Simple Example -@section Simple Example +The second set of regular expressions is much more powerful. This is the +type of regular expressions recognized by utilities such as @code{grep}. -@noindent +The following is the form of a regular expression, expressed in same BNF +style as is found in the Ada Reference Manual: -Let's take a very simple example using the first @command{gnattest} example -located in: +@example +regexp ::= term @{| term@} -- alternation (term or term ...) -@smallexample -<install_prefix>/share/examples/gnattest/simple -@end smallexample +term ::= item @{item@} -- concatenation (item then item) -This project contains a simple package containing one subprogram. By running gnattest: +item ::= elmt -- match elmt +item ::= elmt * -- zero or more elmt's +item ::= elmt + -- one or more elmt's +item ::= elmt ? -- matches elmt or nothing -@smallexample -$ gnattest --harness-dir=driver -Psimple.gpr -@end smallexample +elmt ::= nschar -- matches given character +elmt ::= [nschar @{nschar@}] -- matches any character listed +elmt ::= [^ nschar @{nschar@}] -- matches any character not listed +elmt ::= [char - char] -- matches chars in given range +elmt ::= \\ char -- matches given character +elmt ::= . -- matches any single character +elmt ::= ( regexp ) -- parens used for grouping -a test driver is created in directory "driver". It can be compiled and run: +char ::= any character, including special characters +nschar ::= any character except ()[].*+?^ +@end example -@smallexample -$ cd obj/driver -$ gnatmake -Ptest_driver -$ test_runner -@end smallexample +Here are a few examples: -One failed test with diagnosis "test not implemented" is reported. -Since no special output option was specified, the test package Simple.Tests -is located in: +@quotation -@smallexample -<install_prefix>/share/examples/gnattest/simple/obj/gnattest/tests -@end smallexample -For each package containing visible subprograms, a child test package is -generated. It contains one test routine per tested subprogram. Each -declaration of a test subprogram has a comment specifying which tested -subprogram it corresponds to. Bodies of test routines are placed in test package -bodies and are surrounded by special comment sections. Those comment sections -should not be removed or modified in order for gnattest to be able to regenerate -test packages and keep already written tests in place. -The test routine Test_Inc_5eaee3 located at simple-test_data-tests.adb contains -a single statement: a call to procedure Assert. It has two arguments: -the Boolean expression we want to check and the diagnosis message to display if -the condition is false. +@table @asis -That is where actual testing code should be written after a proper setup. -An actual check can be performed by replacing the Assert call with: +@item @code{abcde|fghi} -@smallexample @c ada -Assert (Inc (1) = 2, "wrong incrementation"); -@end smallexample +will match any of the two strings @code{abcde} and @code{fghi}, -After recompiling and running the test driver, one successfully passed test -is reported. +@item @code{abc*d} -@node Setting Up and Tearing Down the Testing Environment -@section Setting Up and Tearing Down the Testing Environment +will match any string like @code{abd}, @code{abcd}, @code{abccd}, +@code{abcccd}, and so on, -@noindent +@item @code{[a-z]+} -Besides test routines themselves, each test package has a parent package -Test_Data that has two procedures: Set_Up and Tear_Down. This package is never -overwritten by the tool. Set_Up is called before each test routine of the -package and Tear_Down is called after each test routine. Those two procedures -can be used to perform necessary initialization and finalization, -memory allocation, etc. Test type declared in Test_Data package is parent type -for the test type of test package and can have user-defined components whose -values can be set by Set_Up routine and used in test routines afterwards. +will match any string which has only lowercase characters in it (and at +least one character. +@end table +@end quotation +@end table +@end itemize -@node Regenerating Tests -@section Regenerating Tests +@node Examples of gnatxref Usage,Examples of gnatfind Usage,Regular Expressions in gnatfind and gnatxref,The Cross-Referencing Tools gnatxref and gnatfind +@anchor{gnat_ugn/gnat_utility_programs examples-of-gnatxref-usage}@anchor{1dd}@anchor{gnat_ugn/gnat_utility_programs id14}@anchor{1e5} +@subsection Examples of @cite{gnatxref} Usage -@noindent -Bodies of test routines and test_data packages are never overridden after they -have been created once. As long as the name of the subprogram, full expanded Ada -names, and the order of its parameters is the same, and comment sections are -intact the old test routine will fit in its place and no test skeleton will be -generated for the subprogram. +@menu +* General Usage:: +* Using gnatxref with vi:: -This can be demonstrated with the previous example. By uncommenting declaration -and body of function Dec in simple.ads and simple.adb, running -@command{gnattest} on the project, and then running the test driver: +@end menu -@smallexample -gnattest --harness-dir=driver -Psimple.gpr -cd obj/driver -gnatmake -Ptest_driver -test_runner -@end smallexample +@node General Usage,Using gnatxref with vi,,Examples of gnatxref Usage +@anchor{gnat_ugn/gnat_utility_programs general-usage}@anchor{1e6} +@subsubsection General Usage -the old test is not replaced with a stub, nor is it lost, but a new test -skeleton is created for function Dec. -The only way of regenerating tests skeletons is to remove the previously created -tests together with corresponding comment sections. +For the following examples, we will consider the following units: -@node Default Test Behavior -@section Default Test Behavior +@quotation -@noindent +@example +main.ads: +1: with Bar; +2: package Main is +3: procedure Foo (B : in Integer); +4: C : Integer; +5: private +6: D : Integer; +7: end Main; -The generated test driver can treat unimplemented tests in two ways: -either count them all as failed (this is useful to see which tests are still -left to implement) or as passed (to sort out unimplemented ones from those -actually failing). - -The test driver accepts a switch to specify this behavior: ---skeleton-default=val, where val is either "pass" or "fail" (exactly as for -@command{gnattest}). - -The default behavior of the test driver is set with the same switch -as passed to gnattest when generating the test driver. - -Passing it to the driver generated on the first example: - -@smallexample -test_runner --skeleton-default=pass -@end smallexample - -makes both tests pass, even the unimplemented one. - -@node Testing Primitive Operations of Tagged Types -@section Testing Primitive Operations of Tagged Types - -@noindent - -Creation of test skeletons for primitive operations of tagged types entails -a number of features. Test routines for all primitives of a given tagged type -are placed in a separate child package named according to the tagged type. For -example, if you have tagged type T in package P, all tests for primitives -of T will be in P.T_Test_Data.T_Tests. - -Consider running gnattest on the second example (note: actual tests for this -example already exist, so there's no need to worry if the tool reports that -no new stubs were generated): - -@smallexample -cd <install_prefix>/share/examples/gnattest/tagged_rec -gnattest --harness-dir=driver -Ptagged_rec.gpr -@end smallexample - -Taking a closer look at the test type declared in the test package -Speed1.Controller_Test_Data is necessary. It is declared in: - -@smallexample -<install_prefix>/share/examples/gnattest/tagged_rec/obj/gnattest/tests -@end smallexample - -Test types are direct or indirect descendants of -AUnit.Test_Fixtures.Test_Fixture type. In the case of nonprimitive tested -subprograms, the user doesn't need to be concerned with them. However, -when generating test packages for primitive operations, there are some things -the user needs to know. - -Type Test_Controller has components that allow assignment of various -derivations of type Controller. And if you look at the specification of -package Speed2.Auto_Controller, you will see that Test_Auto_Controller -actually derives from Test_Controller rather than AUnit type Test_Fixture. -Thus, test types mirror the hierarchy of tested types. - -The Set_Up procedure of Test_Data package corresponding to a test package -of primitive operations of type T assigns to Fixture a reference to an -object of that exact type T. Notice, however, that if the tagged type has -discriminants, the Set_Up only has a commented template for setting -up the fixture, since filling the discriminant with actual value is up -to the user. - -The knowledge of the structure of test types allows additional testing -without additional effort. Those possibilities are described below. - -@node Testing Inheritance -@section Testing Inheritance - -@noindent - -Since the test type hierarchy mimics the hierarchy of tested types, the -inheritance of tests takes place. An example of such inheritance can be -seen by running the test driver generated for the second example. As previously -mentioned, actual tests are already written for this example. - -@smallexample -cd obj/driver -gnatmake -Ptest_driver -test_runner -@end smallexample - -There are 6 passed tests while there are only 5 testable subprograms. The test -routine for function Speed has been inherited and run against objects of the -derived type. - -@node Tagged Types Substitutability Testing -@section Tagged Types Substitutability Testing - -@noindent - -Tagged Types Substitutability Testing is a way of verifying the global type -consistency by testing. Global type consistency is a principle stating that if -S is a subtype of T (in Ada, S is a derived type of tagged type T), -then objects of type T may be replaced with objects of type S (that is, -objects of type S may be substituted for objects of type T), without -altering any of the desirable properties of the program. When the properties -of the program are expressed in the form of subprogram preconditions and -postconditions (let's call them pre and post), the principle is formulated as -relations between the pre and post of primitive operations and the pre and post -of their derived operations. The pre of a derived operation should not be -stronger than the original pre, and the post of the derived operation should -not be weaker than the original post. Those relations ensure that verifying if -a dispatching call is safe can be done just by using the pre and post of the -root operation. - -Verifying global type consistency by testing consists of running all the unit -tests associated with the primitives of a given tagged type with objects of its -derived types. - -In the example used in the previous section, there was clearly a violation of -type consistency. The overriding primitive Adjust_Speed in package Speed2 -removes the functionality of the overridden primitive and thus doesn't respect -the consistency principle. -Gnattest has a special option to run overridden parent tests against objects -of the type which have overriding primitives: - -@smallexample -gnattest --harness-dir=driver --validate-type-extensions -Ptagged_rec.gpr -cd obj/driver -gnatmake -Ptest_driver -test_runner -@end smallexample - -While all the tests pass by themselves, the parent test for Adjust_Speed fails -against objects of the derived type. - -Non-overridden tests are already inherited for derived test types, so the ---validate-type-extensions enables the application of overriden tests to objects -of derived types. - -@node Testing with Contracts -@section Testing with Contracts - -@noindent - -@command{gnattest} supports pragmas Precondition, Postcondition, and Test_Case, -as well as corresponding aspects. -Test routines are generated, one per each Test_Case associated with a tested -subprogram. Those test routines have special wrappers for tested functions -that have composition of pre- and postcondition of the subprogram with -"requires" and "ensures" of the Test_Case (depending on the mode, pre and post -either count for Nominal mode or do not count for Robustness mode). - -The third example demonstrates how this works: - -@smallexample -cd <install_prefix>/share/examples/gnattest/contracts -gnattest --harness-dir=driver -Pcontracts.gpr -@end smallexample - -Putting actual checks within the range of the contract does not cause any -error reports. For example, for the test routine which corresponds to -test case 1: - -@smallexample @c ada -Assert (Sqrt (9.0) = 3.0, "wrong sqrt"); -@end smallexample - -and for the test routine corresponding to test case 2: - -@smallexample @c ada -Assert (Sqrt (-5.0) = -1.0, "wrong error indication"); -@end smallexample - -are acceptable: - -@smallexample -cd obj/driver -gnatmake -Ptest_driver -test_runner -@end smallexample - -However, by changing 9.0 to 25.0 and 3.0 to 5.0, for example, you can get -a precondition violation for test case one. Also, by using any otherwise -correct but positive pair of numbers in the second test routine, you can also -get a precondition violation. Postconditions are checked and reported -the same way. - -@node Additional Tests -@section Additional Tests - -@noindent -@command{gnattest} can add user-written tests to the main suite of the test -driver. @command{gnattest} traverses the given packages and searches for test -routines. All procedures with a single in out parameter of a type which is -derived from AUnit.Test_Fixtures.Test_Fixture and that are declared in package -specifications are added to the suites and are then executed by the test driver. -(Set_Up and Tear_Down are filtered out.) - -An example illustrates two ways of creating test harnesses for user-written -tests. Directory additional_tests contains an AUnit-based test driver written -by hand. - -@smallexample -<install_prefix>/share/examples/gnattest/additional_tests/ -@end smallexample - -To create a test driver for already-written tests, use the --harness-only -option: +main.adb: +1: package body Main is +2: procedure Foo (B : in Integer) is +3: begin +4: C := B; +5: D := B; +6: Bar.Print (B); +7: Bar.Print (C); +8: end Foo; +9: end Main; -@smallexample -gnattest -Padditional/harness/harness.gpr --harness-dir=harness_only \ - --harness-only -gnatmake -Pharness_only/test_driver.gpr -harness_only/test_runner -@end smallexample - -Additional tests can also be executed together with generated tests: - -@smallexample -gnattest -Psimple.gpr --additional-tests=additional/harness/harness.gpr \ - --harness-dir=mixing -gnatmake -Pmixing/test_driver.gpr -mixing/test_runner -@end smallexample - - -@node Individual Test Drivers -@section Individual Test Drivers - -@noindent -By default, @command{gnattest} generates a monolithic test driver that -aggregates the individual tests into a single executable. It is also possible -to generate separate executables for each test, by passing the switch -@option{--separate-drivers}. This approach scales better for large testing -campaigns, especially involving target architectures with limited resources -typical for embedded development. It can also provide a major performance -benefit on multi-core systems by allowing simultaneous execution of multiple -tests. - -@command{gnattest} can take charge of executing the individual tests; for this, -instead of passing a project file, a text file containing the list of -executables can be passed. Such a file is automatically generated by gnattest -under the name @option{test_drivers.list}, but it can be -hand-edited to add or remove tests, or replaced. The individual tests can -also be executed standalone, or from any user-defined scripted framework. - - -@node Stubbing -@section Stubbing - -@noindent -Depending on the testing campaign, it is sometimes necessary to isolate the -part of the algorithm under test from its dependencies. This is accomplished -via @emph{stubbing}, i.e. replacing the subprograms that are called from the -subprogram under test by stand-in subprograms that match the profiles of the -original ones, but simply return predetermined values required by the test -scenario. - -This mode of test harness generation is activated by the switch @option{--stub}. - -The implementation approach chosen by @command{gnattest} is as follows. -For each package under consideration all the packages it is directly depending -on are stubbed, excluding the generic packages and package instantiations. -The stubs are shared for each package under test. The specs of packages to stub -remain intact, while their bodies are replaced, and hide the original bodies by -means of extending projects. Also, for each stubbed -package, a child package with setter routines for each subprogram declaration -is created. These setters are meant to be used to set the behaviour of -stubbed subprograms from within test cases. - -Note that subprograms belonging to the same package as the subprogram under -test are not stubbed. This guarantees that the sources being tested are -exactly the sources used for production, which is an important property for -establishing the traceability between the testing campaign and production code. - -Due to the nature of stubbing process, this mode implies the switch -@option{--separate-drivers}, i.e. an individual test driver (with the -corresponding hierarchy of extending projects) is generated for each test. - -@quotation Note -Developing a stubs-based testing campaign requires -good understanding of the infrastructure created by @command{gnattest} for -this purpose. We recommend following the stubbing tutorials provided -under @file{<install_prefix>/share/examples/gnattest/stubbing*} before -attempting to use this powerful feature. +bar.ads: +1: package Bar is +2: procedure Print (B : Integer); +3: end bar; +@end example @end quotation -@node Putting Tests under Version Control -@section Putting Tests under Version Control +The first thing to do is to recompile your application (for instance, in +that case just by doing a @code{gnatmake main}, so that GNAT generates +the cross-referencing information. +You can then issue any of the following commands: -@noindent -As has been stated earlier, @command{gnattest} generates two different types -of code, test skeletons and harness. The harness is generated completely -automatically each time, does not require manual changes and therefore should -not be put under version control. -It makes sense to put under version control files containing test data packages, -both specs and bodies, and files containing bodies of test packages. Note that -test package specs are also generated automatically each time and should not be -put under version control. -Option @option{--omit-sloc} may be usefull when putting test packages under VCS. +@quotation -@node Support for other platforms/run-times -@section Support for other platforms/run-times -@noindent -@command{gnattest} can be used to generate the test harness for platforms -and run-time libraries others than the default native target with the -default full run-time. For example, when using a limited run-time library -such as Zero FootPrint (ZFP), a simplified harness is generated. +@itemize * -Two variables are used to tell the underlying AUnit framework how to generate -the test harness: @code{PLATFORM}, which identifies the target, and -@code{RUNTIME}, used to determine the run-time library for which the harness -is generated. Corresponding prefix should also be used when calling -@command{gnattest} for non-native targets. For example, the following options -are used to generate the AUnit test harness for a PowerPC ELF target using -the ZFP run-time library: +@item +@code{gnatxref main.adb} +@cite{gnatxref} generates cross-reference information for main.adb +and every unit 'with'ed by main.adb. -@smallexample -powerpc-elf-gnattest -Psimple.gpr -XPLATFORM=powerpc-elf -XRUNTIME=zfp -@end smallexample +The output would be: -@node Current Limitations -@section Current Limitations +@quotation -@noindent +@example +B Type: Integer + Decl: bar.ads 2:22 +B Type: Integer + Decl: main.ads 3:20 + Body: main.adb 2:20 + Ref: main.adb 4:13 5:13 6:19 +Bar Type: Unit + Decl: bar.ads 1:9 + Ref: main.adb 6:8 7:8 + main.ads 1:6 +C Type: Integer + Decl: main.ads 4:5 + Modi: main.adb 4:8 + Ref: main.adb 7:19 +D Type: Integer + Decl: main.ads 6:5 + Modi: main.adb 5:8 +Foo Type: Unit + Decl: main.ads 3:15 + Body: main.adb 2:15 +Main Type: Unit + Decl: main.ads 2:9 + Body: main.adb 1:14 +Print Type: Unit + Decl: bar.ads 2:15 + Ref: main.adb 6:12 7:12 +@end example +@end quotation -The tool currently does not support following features: +This shows that the entity @cite{Main} is declared in main.ads, line 2, column 9, +its body is in main.adb, line 1, column 14 and is not referenced any where. -@itemize @bullet -@item generic tests for nested generic packages and their instantiations -@item tests for protected subprograms and entries +The entity @cite{Print} is declared in bar.ads, line 2, column 15 and it +is referenced in main.adb, line 6 column 12 and line 7 column 12. +@item +@code{gnatxref package1.adb package2.ads} +@cite{gnatxref} will generates cross-reference information for +package1.adb, package2.ads and any other package 'with'ed by any +of these. @end itemize -@end ifclear +@end quotation +@node Using gnatxref with vi,,General Usage,Examples of gnatxref Usage +@anchor{gnat_ugn/gnat_utility_programs using-gnatxref-with-vi}@anchor{1e7} +@subsubsection Using gnatxref with vi -@c ********************************* -@node Performing Dimensionality Analysis in GNAT -@chapter Performing Dimensionality Analysis in GNAT -@cindex Dimensionality analysis -@noindent -The GNAT compiler now supports dimensionality checking. The user can -specify physical units for objects, and the compiler will verify that uses -of these objects are compatible with their dimensions, in a fashion that is -familiar to engineering practice. The dimensions of algebraic expressions -(including powers with static exponents) are computed from their constituents. +@cite{gnatxref} can generate a tags file output, which can be used +directly from @emph{vi}. Note that the standard version of @emph{vi} +will not work properly with overloaded symbols. Consider using another +free implementation of @emph{vi}, such as @emph{vim}. -This feature depends on Ada 2012 aspect specifications, and is available from -version 7.0.1 of GNAT onwards. -The GNAT-specific aspect @code{Dimension_System} -@cindex @code{Dimension_System} aspect -allows you to define a system of units; the aspect @code{Dimension} -@cindex @code{Dimension} aspect -then allows the user to declare dimensioned quantities within a given system. -(These aspects are described in the @i{Implementation Defined Aspects} -chapter of the @i{GNAT Reference Manual}). +@quotation -The major advantage of this model is that it does not require the declaration of -multiple operators for all possible combinations of types: it is only necessary -to use the proper subtypes in object declarations. +@example +$ gnatxref -v gnatfind.adb > tags +@end example +@end quotation -The simplest way to impose dimensionality checking on a computation is to make -use of the package @code{System.Dim.Mks}, -@cindex @code{System.Dim.Mks} package (GNAT library) -which is part of the GNAT library. This -package defines a floating-point type @code{MKS_Type}, -@cindex @code{MKS_Type} type -for which a sequence of -dimension names are specified, together with their conventional abbreviations. -The following should be read together with the full specification of the -package, in file @file{s-dimmks.ads}. -@cindex @file{s-dimmks.ads} file - -@smallexample @c ada -@group - @b{type} Mks_Type @b{is} @b{new} Long_Long_Float - @b{with} - Dimension_System => ( - (Unit_Name => Meter, Unit_Symbol => 'm', Dim_Symbol => 'L'), - (Unit_Name => Kilogram, Unit_Symbol => "kg", Dim_Symbol => 'M'), - (Unit_Name => Second, Unit_Symbol => 's', Dim_Symbol => 'T'), - (Unit_Name => Ampere, Unit_Symbol => 'A', Dim_Symbol => 'I'), - (Unit_Name => Kelvin, Unit_Symbol => 'K', Dim_Symbol => "Theta"), - (Unit_Name => Mole, Unit_Symbol => "mol", Dim_Symbol => 'N'), - (Unit_Name => Candela, Unit_Symbol => "cd", Dim_Symbol => 'J')); -@end group -@end smallexample - -@noindent -The package then defines a series of subtypes that correspond to these -conventional units. For example: +The following command will generate the tags file for @cite{gnatfind} itself +(if the sources are in the search path!): -@smallexample @c ada -@group - @b{subtype} Length @b{is} Mks_Type - @b{with} - Dimension => (Symbol => 'm', Meter => 1, @b{others} => 0); -@end group -@end smallexample +@quotation -@noindent -and similarly for @code{Mass}, @code{Time}, @code{Electric_Current}, -@code{Thermodynamic_Temperature}, @code{Amount_Of_Substance}, and -@code{Luminous_Intensity} (the standard set of units of the SI system). +@example +$ gnatxref -v gnatfind.adb > tags +@end example +@end quotation -The package also defines conventional names for values of each unit, for -example: +From @emph{vi}, you can then use the command @code{:tag @emph{entity}} +(replacing @cite{entity} by whatever you are looking for), and vi will +display a new file with the corresponding declaration of entity. -@smallexample @c ada -@group - m : @b{constant} Length := 1.0; - kg : @b{constant} Mass := 1.0; - s : @b{constant} Time := 1.0; - A : @b{constant} Electric_Current := 1.0; -@end group -@end smallexample +@node Examples of gnatfind Usage,,Examples of gnatxref Usage,The Cross-Referencing Tools gnatxref and gnatfind +@anchor{gnat_ugn/gnat_utility_programs id15}@anchor{1e8}@anchor{gnat_ugn/gnat_utility_programs examples-of-gnatfind-usage}@anchor{1e1} +@subsection Examples of @cite{gnatfind} Usage -@noindent -as well as useful multiples of these units: -@smallexample @c ada -@group - cm : @b{constant} Length := 1.0E-02; - g : @b{constant} Mass := 1.0E-03; - min : @b{constant} Time := 60.0; - day : @b{constant} Time := 60.0 * 24.0 * min; - ... -@end group -@end smallexample -@noindent -Using this package, you can then define a derived unit by -providing the aspect that -specifies its dimensions within the MKS system, as well as the string to -be used for output of a value of that unit: +@itemize * -@smallexample @c ada -@group - @b{subtype} Acceleration @b{is} Mks_Type - @b{with} Dimension => ("m/sec^2", - Meter => 1, - Second => -2, - @b{others} => 0); -@end group -@end smallexample - -@noindent -Here is a complete example of use: +@item +@code{gnatfind -f xyz:main.adb} +Find declarations for all entities xyz referenced at least once in +main.adb. The references are search in every library file in the search +path. -@smallexample @c ada -@group -@b{with} System.Dim.MKS; @b{use} System.Dim.Mks; -@b{with} System.Dim.Mks_IO; @b{use} System.Dim.Mks_IO; -@b{with} Text_IO; @b{use} Text_IO; -@b{procedure} Free_Fall @b{is} - @b{subtype} Acceleration @b{is} Mks_Type - @b{with} Dimension => ("m/sec^2", 1, 0, -2, @b{others} => 0); - G : @b{constant} acceleration := 9.81 * m / (s ** 2); - T : Time := 10.0*s; - Distance : Length; -@end group -@group -@b{begin} - Put ("Gravitational constant: "); - Put (G, Aft => 2, Exp => 0); Put_Line (""); - Distance := 0.5 * G * T ** 2; - Put ("distance travelled in 10 seconds of free fall "); - Put (Distance, Aft => 2, Exp => 0); - Put_Line (""); -@b{end} Free_Fall; -@end group -@end smallexample +The directories will be printed as well (as the @code{-f} +switch is set) -@noindent -Execution of this program yields: -@smallexample -@group -Gravitational constant: 9.81 m/sec^2 -distance travelled in 10 seconds of free fall 490.50 m -@end group -@end smallexample +The output will look like: -@noindent -However, incorrect assignments such as: +@quotation -@smallexample @c ada -@group - Distance := 5.0; - Distance := 5.0 * kg: -@end group -@end smallexample +@example +directory/main.ads:106:14: xyz <= declaration +directory/main.adb:24:10: xyz <= body +directory/foo.ads:45:23: xyz <= declaration +@end example +@end quotation -@noindent -are rejected with the following diagnoses: +I.e., one of the entities xyz found in main.adb is declared at +line 12 of main.ads (and its body is in main.adb), and another one is +declared at line 45 of foo.ads -@smallexample -@group - Distance := 5.0; - >>> dimensions mismatch in assignment - >>> left-hand side has dimension [L] - >>> right-hand side is dimensionless -@end group - -@group - Distance := 5.0 * kg: - >>> dimensions mismatch in assignment - >>> left-hand side has dimension [L] - >>> right-hand side has dimension [M] -@end group -@end smallexample - -@noindent -The dimensions of an expression are properly displayed, even if there is -no explicit subtype for it. If we add to the program: +@item +@code{gnatfind -fs xyz:main.adb} +This is the same command as the previous one, but @cite{gnatfind} will +display the content of the Ada source file lines. -@smallexample @c ada -@group - Put ("Final velocity: "); - Put (G * T, Aft =>2, Exp =>0); - Put_Line (""); -@end group -@end smallexample +The output will look like: -@noindent -then the output includes: -@smallexample - Final velocity: 98.10 m.s**(-1) -@end smallexample +@example +directory/main.ads:106:14: xyz <= declaration + procedure xyz; +directory/main.adb:24:10: xyz <= body + procedure xyz is +directory/foo.ads:45:23: xyz <= declaration + xyz : Integer; +@end example +This can make it easier to find exactly the location your are looking +for. -@c ********************************* -@node Generating Ada Bindings for C and C++ headers -@chapter Generating Ada Bindings for C and C++ headers -@findex binding +@item +@code{gnatfind -r "*x*":main.ads:123 foo.adb} +Find references to all entities containing an x that are +referenced on line 123 of main.ads. +The references will be searched only in main.ads and foo.adb. -@noindent -GNAT now comes with a binding generator for C and C++ headers which is -intended to do 95% of the tedious work of generating Ada specs from C -or C++ header files. +@item +@code{gnatfind main.ads:123} +Find declarations and bodies for all entities that are referenced on +line 123 of main.ads. -Note that this capability is not intended to generate 100% correct Ada specs, -and will is some cases require manual adjustments, although it can often -be used out of the box in practice. +This is the same as @code{gnatfind "*":main.adb:123`} -Some of the known limitations include: +@item +@code{gnatfind mydir/main.adb:123:45} +Find the declaration for the entity referenced at column 45 in +line 123 of file main.adb in directory mydir. Note that it +is usual to omit the identifier name when the column is given, +since the column position identifies a unique reference. -@itemize @bullet -@item only very simple character constant macros are translated into Ada -constants. Function macros (macros with arguments) are partially translated -as comments, to be completed manually if needed. -@item some extensions (e.g. vector types) are not supported -@item pointers to pointers or complex structures are mapped to System.Address -@item identifiers with identical name (except casing) will generate compilation - errors (e.g. @code{shm_get} vs @code{SHM_GET}). +The column has to be the beginning of the identifier, and should not +point to any character in the middle of the identifier. @end itemize -The code generated is using the Ada 2005 syntax, which makes it -easier to interface with other languages than previous versions of Ada. - -@menu -* Running the binding generator:: -* Generating bindings for C++ headers:: -* Switches:: -@end menu - -@node Running the binding generator -@section Running the binding generator - -@noindent -The binding generator is part of the @command{gcc} compiler and can be -invoked via the @option{-fdump-ada-spec} switch, which will generate Ada -spec files for the header files specified on the command line, and all -header files needed by these files transitively. For example: - -@smallexample -$ g++ -c -fdump-ada-spec -C /usr/include/time.h -$ gcc -c -gnat05 *.ads -@end smallexample - -will generate, under GNU/Linux, the following files: @file{time_h.ads}, -@file{bits_time_h.ads}, @file{stddef_h.ads}, @file{bits_types_h.ads} which -correspond to the files @file{/usr/include/time.h}, -@file{/usr/include/bits/time.h}, etc@dots{}, and will then compile in Ada 2005 -mode these Ada specs. - -The @code{-C} switch tells @command{gcc} to extract comments from headers, -and will attempt to generate corresponding Ada comments. +@node The Ada to HTML Converter gnathtml,,The Cross-Referencing Tools gnatxref and gnatfind,GNAT Utility Programs +@anchor{gnat_ugn/gnat_utility_programs the-ada-to-html-converter-gnathtml}@anchor{25}@anchor{gnat_ugn/gnat_utility_programs id16}@anchor{1e9} +@section The Ada to HTML Converter @cite{gnathtml} -If you want to generate a single Ada file and not the transitive closure, you -can use instead the @option{-fdump-ada-spec-slim} switch. -You can optionally specify a parent unit, of which all generated units will -be children, using @code{-fada-spec-parent=}@var{unit}. +@geindex gnathtml -Note that we recommend when possible to use the @command{g++} driver to -generate bindings, even for most C headers, since this will in general -generate better Ada specs. For generating bindings for C++ headers, it is -mandatory to use the @command{g++} command, or @command{gcc -x c++} which -is equivalent in this case. If @command{g++} cannot work on your C headers -because of incompatibilities between C and C++, then you can fallback to -@command{gcc} instead. +@emph{gnathtml} is a Perl script that allows Ada source files to be browsed using +standard Web browsers. For installation information, see @ref{1ea,,Installing gnathtml}. -For an example of better bindings generated from the C++ front-end, -the name of the parameters (when available) are actually ignored by the C -front-end. Consider the following C header: - -@smallexample -extern void foo (int variable); -@end smallexample - -with the C front-end, @code{variable} is ignored, and the above is handled as: +Ada reserved keywords are highlighted in a bold font and Ada comments in +a blue font. Unless your program was compiled with the gcc @emph{-gnatx} +switch to suppress the generation of cross-referencing information, user +defined variables and types will appear in a different color; you will +be able to click on any identifier and go to its declaration. -@smallexample -extern void foo (int); -@end smallexample +@menu +* Invoking gnathtml:: +* Installing gnathtml:: -generating a generic: +@end menu -@smallexample -procedure foo (param1 : int); -@end smallexample +@node Invoking gnathtml,Installing gnathtml,,The Ada to HTML Converter gnathtml +@anchor{gnat_ugn/gnat_utility_programs invoking-gnathtml}@anchor{1eb}@anchor{gnat_ugn/gnat_utility_programs id17}@anchor{1ec} +@subsection Invoking @emph{gnathtml} -with the C++ front-end, the name is available, and we generate: -@smallexample -procedure foo (variable : int); -@end smallexample +The command line is as follows: -In some cases, the generated bindings will be more complete or more meaningful -when defining some macros, which you can do via the @option{-D} switch. This -is for example the case with @file{Xlib.h} under GNU/Linux: +@quotation -@smallexample -g++ -c -fdump-ada-spec -DXLIB_ILLEGAL_ACCESS -C /usr/include/X11/Xlib.h -@end smallexample +@example +$ perl gnathtml.pl [`switches`] `ada-files` +@end example +@end quotation -The above will generate more complete bindings than a straight call without -the @option{-DXLIB_ILLEGAL_ACCESS} switch. +You can specify as many Ada files as you want. @cite{gnathtml} will generate +an html file for every ada file, and a global file called @code{index.htm}. +This file is an index of every identifier defined in the files. -In other cases, it is not possible to parse a header file in a stand-alone -manner, because other include files need to be included first. In this -case, the solution is to create a small header file including the needed -@code{#include} and possible @code{#define} directives. For example, to -generate Ada bindings for @file{readline/readline.h}, you need to first -include @file{stdio.h}, so you can create a file with the following two -lines in e.g. @file{readline1.h}: +The following switches are available: -@smallexample -#include <stdio.h> -#include <readline/readline.h> -@end smallexample +@geindex -83 (gnathtml) -and then generate Ada bindings from this file: -@smallexample -$ g++ -c -fdump-ada-spec readline1.h -@end smallexample +@table @asis -@node Generating bindings for C++ headers -@section Generating bindings for C++ headers +@item @code{83} -@noindent -Generating bindings for C++ headers is done using the same options, always -with the @command{g++} compiler. +Only the Ada 83 subset of keywords will be highlighted. +@end table -In this mode, C++ classes will be mapped to Ada tagged types, constructors -will be mapped using the @code{CPP_Constructor} pragma, and when possible, -multiple inheritance of abstract classes will be mapped to Ada interfaces -(@xref{Interfacing to C++,,,gnat_rm, GNAT Reference Manual}, for additional -information on interfacing to C++). +@geindex -cc (gnathtml) -For example, given the following C++ header file: -@smallexample -@group -@cartouche -class Carnivore @{ -public: - virtual int Number_Of_Teeth () = 0; -@}; +@table @asis -class Domestic @{ -public: - virtual void Set_Owner (char* Name) = 0; -@}; +@item @code{cc @emph{color}} -class Animal @{ -public: - int Age_Count; - virtual void Set_Age (int New_Age); -@}; +This option allows you to change the color used for comments. The default +value is green. The color argument can be any name accepted by html. +@end table -class Dog : Animal, Carnivore, Domestic @{ - public: - int Tooth_Count; - char *Owner; +@geindex -d (gnathtml) - virtual int Number_Of_Teeth (); - virtual void Set_Owner (char* Name); - Dog(); -@}; -@end cartouche -@end group -@end smallexample +@table @asis -The corresponding Ada code is generated: +@item @code{d} -@smallexample @c ada -@group -@cartouche - @b{package} Class_Carnivore @b{is} - @b{type} Carnivore @b{is} @b{limited} interface; - @b{pragma} Import (CPP, Carnivore); - - @b{function} Number_Of_Teeth (this : @b{access} Carnivore) @b{return} int @b{is} @b{abstract}; - @b{end}; - @b{use} Class_Carnivore; - - @b{package} Class_Domestic @b{is} - @b{type} Domestic @b{is} @b{limited} interface; - @b{pragma} Import (CPP, Domestic); - - @b{procedure} Set_Owner - (this : @b{access} Domestic; - Name : Interfaces.C.Strings.chars_ptr) @b{is} @b{abstract}; - @b{end}; - @b{use} Class_Domestic; - - @b{package} Class_Animal @b{is} - @b{type} Animal @b{is} @b{tagged} @b{limited} @b{record} - Age_Count : @b{aliased} int; - @b{end} @b{record}; - @b{pragma} Import (CPP, Animal); - - @b{procedure} Set_Age (this : @b{access} Animal; New_Age : int); - @b{pragma} Import (CPP, Set_Age, "_ZN6Animal7Set_AgeEi"); - @b{end}; - @b{use} Class_Animal; - - @b{package} Class_Dog @b{is} - @b{type} Dog @b{is} @b{new} Animal @b{and} Carnivore @b{and} Domestic @b{with} @b{record} - Tooth_Count : @b{aliased} int; - Owner : Interfaces.C.Strings.chars_ptr; - @b{end} @b{record}; - @b{pragma} Import (CPP, Dog); - - @b{function} Number_Of_Teeth (this : @b{access} Dog) @b{return} int; - @b{pragma} Import (CPP, Number_Of_Teeth, "_ZN3Dog15Number_Of_TeethEv"); - - @b{procedure} Set_Owner - (this : @b{access} Dog; Name : Interfaces.C.Strings.chars_ptr); - @b{pragma} Import (CPP, Set_Owner, "_ZN3Dog9Set_OwnerEPc"); - - @b{function} New_Dog @b{return} Dog; - @b{pragma} CPP_Constructor (New_Dog); - @b{pragma} Import (CPP, New_Dog, "_ZN3DogC1Ev"); - @b{end}; - @b{use} Class_Dog; -@end cartouche -@end group -@end smallexample +If the Ada files depend on some other files (for instance through +@cite{with} clauses, the latter files will also be converted to html. +Only the files in the user project will be converted to html, not the files +in the run-time library itself. +@end table -@node Switches -@section Switches +@geindex -D (gnathtml) -@table @option -@item -fdump-ada-spec -@cindex @option{-fdump-ada-spec} (@command{gcc}) -Generate Ada spec files for the given header files transitively (including -all header files that these headers depend upon). -@item -fdump-ada-spec-slim -@cindex @option{-fdump-ada-spec-slim} (@command{gcc}) -Generate Ada spec files for the header files specified on the command line -only. +@table @asis -@item -fada-spec-parent=@var{unit} -@cindex -fada-spec-parent (@command{gcc}) -Specifies that all files generated by @option{-fdump-ada-spec*} are -to be child units of the specified parent unit. +@item @code{D} -@item -C -@cindex @option{-C} (@command{gcc}) -Extract comments from headers and generate Ada comments in the Ada spec files. +This command is the same as @emph{-d} above, but @emph{gnathtml} will +also look for files in the run-time library, and generate html files for them. @end table -@node Other Utility Programs -@chapter Other Utility Programs - -@noindent -This chapter discusses some other utility programs available in the Ada -environment. - -@menu -* Using Other Utility Programs with GNAT:: -* The External Symbol Naming Scheme of GNAT:: -* Converting Ada Files to html with gnathtml:: -* Installing gnathtml:: -@end menu - -@node Using Other Utility Programs with GNAT -@section Using Other Utility Programs with GNAT - -@noindent -The object files generated by GNAT are in standard system format and in -particular the debugging information uses this format. This means -programs generated by GNAT can be used with existing utilities that -depend on these formats. +@geindex -ext (gnathtml) -In general, any utility program that works with C will also often work with -Ada programs generated by GNAT. This includes software utilities such as -gprof (a profiling program), @code{gdb} (the FSF debugger), and utilities such -as Purify. -@node The External Symbol Naming Scheme of GNAT -@section The External Symbol Naming Scheme of GNAT +@table @asis -@noindent -In order to interpret the output from GNAT, when using tools that are -originally intended for use with other languages, it is useful to -understand the conventions used to generate link names from the Ada -entity names. +@item @code{ext @emph{extension}} -All link names are in all lowercase letters. With the exception of library -procedure names, the mechanism used is simply to use the full expanded -Ada name with dots replaced by double underscores. For example, suppose -we have the following package spec: +This option allows you to change the extension of the generated HTML files. +If you do not specify an extension, it will default to @code{htm}. +@end table -@smallexample @c ada -@group -@cartouche -@b{package} QRS @b{is} - MN : Integer; -@b{end} QRS; -@end cartouche -@end group -@end smallexample +@geindex -f (gnathtml) -@noindent -The variable @code{MN} has a full expanded Ada name of @code{QRS.MN}, so -the corresponding link name is @code{qrs__mn}. -@findex Export -Of course if a @code{pragma Export} is used this may be overridden: -@smallexample @c ada -@group -@cartouche -@b{package} Exports @b{is} - Var1 : Integer; - @b{pragma} Export (Var1, C, External_Name => "var1_name"); - Var2 : Integer; - @b{pragma} Export (Var2, C, Link_Name => "var2_link_name"); -@b{end} Exports; -@end cartouche -@end group -@end smallexample +@table @asis -@noindent -In this case, the link name for @var{Var1} is whatever link name the -C compiler would assign for the C function @var{var1_name}. This typically -would be either @var{var1_name} or @var{_var1_name}, depending on operating -system conventions, but other possibilities exist. The link name for -@var{Var2} is @var{var2_link_name}, and this is not operating system -dependent. +@item @code{f} -@findex _main -One exception occurs for library level procedures. A potential ambiguity -arises between the required name @code{_main} for the C main program, -and the name we would otherwise assign to an Ada library level procedure -called @code{Main} (which might well not be the main program). +By default, gnathtml will generate html links only for global entities +('with'ed units, global variables and types,...). If you specify +@emph{-f} on the command line, then links will be generated for local +entities too. +@end table -To avoid this ambiguity, we attach the prefix @code{_ada_} to such -names. So if we have a library level procedure such as +@geindex -l (gnathtml) -@smallexample @c ada -@group -@cartouche -@b{procedure} Hello (S : String); -@end cartouche -@end group -@end smallexample -@noindent -the external name of this procedure will be @var{_ada_hello}. +@table @asis +@item @code{l @emph{number}} -@node Converting Ada Files to html with gnathtml -@section Converting Ada Files to HTML with @code{gnathtml} +If this switch is provided and @cite{number} is not 0, then +@cite{gnathtml} will number the html files every @cite{number} line. +@end table -@noindent -This @code{Perl} script allows Ada source files to be browsed using -standard Web browsers. For installation procedure, see the section -@xref{Installing gnathtml}. +@geindex -I (gnathtml) -Ada reserved keywords are highlighted in a bold font and Ada comments in -a blue font. Unless your program was compiled with the gcc @option{-gnatx} -switch to suppress the generation of cross-referencing information, user -defined variables and types will appear in a different color; you will -be able to click on any identifier and go to its declaration. -The command line is as follow: -@smallexample -@c $ perl gnathtml.pl @ovar{switches} @var{ada-files} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ perl gnathtml.pl @r{[}@var{switches}@r{]} @var{ada-files} -@end smallexample +@table @asis -@noindent -You can pass it as many Ada files as you want. @code{gnathtml} will generate -an html file for every ada file, and a global file called @file{index.htm}. -This file is an index of every identifier defined in the files. +@item @code{I @emph{dir}} -The available switches are the following ones: +Specify a directory to search for library files (@code{.ALI} files) and +source files. You can provide several -I switches on the command line, +and the directories will be parsed in the order of the command line. +@end table -@table @option -@item -83 -@cindex @option{-83} (@code{gnathtml}) -Only the Ada 83 subset of keywords will be highlighted. +@geindex -o (gnathtml) -@item -cc @var{color} -@cindex @option{-cc} (@code{gnathtml}) -This option allows you to change the color used for comments. The default -value is green. The color argument can be any name accepted by html. -@item -d -@cindex @option{-d} (@code{gnathtml}) -If the Ada files depend on some other files (for instance through -@code{with} clauses, the latter files will also be converted to html. -Only the files in the user project will be converted to html, not the files -in the run-time library itself. +@table @asis -@item -D -@cindex @option{-D} (@code{gnathtml}) -This command is the same as @option{-d} above, but @command{gnathtml} will -also look for files in the run-time library, and generate html files for them. +@item @code{o @emph{dir}} -@item -ext @var{extension} -@cindex @option{-ext} (@code{gnathtml}) -This option allows you to change the extension of the generated HTML files. -If you do not specify an extension, it will default to @file{htm}. +Specify the output directory for html files. By default, gnathtml will +saved the generated html files in a subdirectory named @code{html/}. +@end table -@item -f -@cindex @option{-f} (@code{gnathtml}) -By default, gnathtml will generate html links only for global entities -('with'ed units, global variables and types,@dots{}). If you specify -@option{-f} on the command line, then links will be generated for local -entities too. +@geindex -p (gnathtml) -@item -l @var{number} -@cindex @option{-l} (@code{gnathtml}) -If this switch is provided and @var{number} is not 0, then -@code{gnathtml} will number the html files every @var{number} line. -@item -I @var{dir} -@cindex @option{-I} (@code{gnathtml}) -Specify a directory to search for library files (@file{.ALI} files) and -source files. You can provide several -I switches on the command line, -and the directories will be parsed in the order of the command line. +@table @asis -@item -o @var{dir} -@cindex @option{-o} (@code{gnathtml}) -Specify the output directory for html files. By default, gnathtml will -saved the generated html files in a subdirectory named @file{html/}. +@item @code{p @emph{file}} -@item -p @var{file} -@cindex @option{-p} (@code{gnathtml}) If you are using Emacs and the most recent Emacs Ada mode, which provides a full Integrated Development Environment for compiling, checking, -running and debugging applications, you may use @file{.gpr} files +running and debugging applications, you may use @code{.gpr} files to give the directories where Emacs can find sources and object files. Using this switch, you can tell gnathtml to use these files. This allows you to get an html version of your application, even if it is spread over multiple directories. +@end table + +@geindex -sc (gnathtml) + + +@table @asis + +@item @code{sc @emph{color}} -@item -sc @var{color} -@cindex @option{-sc} (@code{gnathtml}) This switch allows you to change the color used for symbol definitions. The default value is red. The color argument can be any name accepted by html. +@end table + +@geindex -t (gnathtml) + + +@table @asis + +@item @code{t @emph{file}} -@item -t @var{file} -@cindex @option{-t} (@code{gnathtml}) This switch provides the name of a file. This file contains a list of file names to be converted, and the effect is exactly as though they had appeared explicitly on the command line. This is the recommended way to work around the command line length limit on some systems. - @end table -@node Installing gnathtml -@section Installing @code{gnathtml} - -@noindent -@code{Perl} needs to be installed on your machine to run this script. -@code{Perl} is freely available for almost every architecture and -Operating System via the Internet. +@node Installing gnathtml,,Invoking gnathtml,The Ada to HTML Converter gnathtml +@anchor{gnat_ugn/gnat_utility_programs installing-gnathtml}@anchor{1ea}@anchor{gnat_ugn/gnat_utility_programs id18}@anchor{1ed} +@subsection Installing @cite{gnathtml} -On Unix systems, you may want to modify the first line of the script -@code{gnathtml}, to explicitly tell the Operating system where Perl -is. The syntax of this line is: -@smallexample -#!full_path_name_to_perl -@end smallexample - -@noindent -Alternatively, you may run the script using the following command line: -@smallexample -@c $ perl gnathtml.pl @ovar{switches} @var{files} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ perl gnathtml.pl @r{[}@var{switches}@r{]} @var{files} -@end smallexample +@cite{Perl} needs to be installed on your machine to run this script. +@cite{Perl} is freely available for almost every architecture and +operating system via the Internet. +On Unix systems, you may want to modify the first line of the script +@cite{gnathtml}, to explicitly specify where Perl +is located. The syntax of this line is: -@c ****************************** -@node Code Coverage and Profiling -@chapter Code Coverage and Profiling -@cindex Code Coverage -@cindex Profiling +@quotation -@noindent -This chapter describes how to use @code{gcov} - coverage testing tool - and -@code{gprof} - profiler tool - on your Ada programs. +@example +#!full_path_name_to_perl +@end example +@end quotation -@menu -* Code Coverage of Ada Programs with gcov:: -* Profiling an Ada Program with gprof:: -@end menu +Alternatively, you may run the script using the following command line: -@node Code Coverage of Ada Programs with gcov -@section Code Coverage of Ada Programs with gcov -@cindex gcov -@cindex -fprofile-arcs -@cindex -ftest-coverage -@cindex -coverage -@cindex Code Coverage +@quotation -@noindent -@code{gcov} is a test coverage program: it analyzes the execution of a given -program on selected tests, to help you determine the portions of the program -that are still untested. +@example +$ perl gnathtml.pl [`switches`] `files` +@end example +@end quotation -@code{gcov} is part of the GCC suite, and is described in detail in the GCC -User's Guide. You can refer to this documentation for a more complete -description. +@c -- +---------------------------------------------------------------------+ -This chapter provides a quick startup guide, and -details some Gnat-specific features. +@c -- | The following sections are present only in the PRO and GPL editions | -@menu -* Quick startup guide:: -* Gnat specifics:: -@end menu +@c -- +---------------------------------------------------------------------+ -@node Quick startup guide -@subsection Quick startup guide -In order to perform coverage analysis of a program using @code{gcov}, 3 -steps are needed: -@itemize @bullet -@item -Code instrumentation during the compilation process -@item -Execution of the instrumented program -@item -Execution of the @code{gcov} tool to generate the result. -@end itemize -The code instrumentation needed by gcov is created at the object level: -The source code is not modified in any way, because the instrumentation code is -inserted by gcc during the compilation process. To compile your code with code -coverage activated, you need to recompile your whole project using the -switches -@code{-fprofile-arcs} and @code{-ftest-coverage}, and link it using -@code{-fprofile-arcs}. -@smallexample -$ gnatmake -P my_project.gpr -f -cargs -fprofile-arcs -ftest-coverage \ - -largs -fprofile-arcs -@end smallexample -This compilation process will create @file{.gcno} files together with -the usual object files. -Once the program is compiled with coverage instrumentation, you can -run it as many times as needed - on portions of a test suite for -example. The first execution will produce @file{.gcda} files at the -same location as the @file{.gcno} files. The following executions -will update those files, so that a cumulative result of the covered -portions of the program is generated. +@c -- Example: A |withing| unit has a |with| clause, it |withs| a |withed| unit -Finally, you need to call the @code{gcov} tool. The different options of -@code{gcov} are available in the GCC User's Guide, section 'Invoking gcov'. +@node GNAT and Program Execution,Platform-Specific Information,GNAT Utility Programs,Top +@anchor{gnat_ugn/gnat_and_program_execution gnat-and-program-execution}@anchor{e}@anchor{gnat_ugn/gnat_and_program_execution doc}@anchor{1ee}@anchor{gnat_ugn/gnat_and_program_execution id1}@anchor{1ef} +@chapter GNAT and Program Execution -This will create annotated source files with a @file{.gcov} extension: -@file{my_main.adb} file will be analysed in @file{my_main.adb.gcov}. -@node Gnat specifics -@subsection Gnat specifics +This chapter covers several topics: -Because Ada semantics, portions of the source code may be shared among -several object files. This is the case for example when generics are -involved, when inlining is active or when declarations generate initialisation -calls. In order to take -into account this shared code, you need to call @code{gcov} on all -source files of the tested program at once. -The list of source files might exceed the system's maximum command line -length. In order to bypass this limitation, a new mechanism has been -implemented in @code{gcov}: you can now list all your project's files into a -text file, and provide this file to gcov as a parameter, preceded by a @@ -(e.g. @samp{gcov @@mysrclist.txt}). +@itemize * -Note that on AIX compiling a static library with @code{-fprofile-arcs} is -not supported as there can be unresolved symbols during the final link. +@item +@ref{1f0,,Running and Debugging Ada Programs} -@node Profiling an Ada Program with gprof -@section Profiling an Ada Program with gprof -@cindex gprof -@cindex -pg -@cindex Profiling +@item +@ref{1f1,,Code Coverage and Profiling} -@noindent -This section is not meant to be an exhaustive documentation of @code{gprof}. -Full documentation for it can be found in the GNU Profiler User's Guide -documentation that is part of this GNAT distribution. +@item +@ref{1f2,,Improving Performance} -Profiling a program helps determine the parts of a program that are executed -most often, and are therefore the most time-consuming. +@item +@ref{1f3,,Overflow Check Handling in GNAT} -@code{gprof} is the standard GNU profiling tool; it has been enhanced to -better handle Ada programs and multitasking. -It is currently supported on the following platforms -@itemize @bullet -@item -linux x86/x86_64 -@item -solaris sparc/sparc64/x86 -@item -windows x86 -@end itemize +@item +@ref{1f4,,Performing Dimensionality Analysis in GNAT} -@noindent -In order to profile a program using @code{gprof}, 3 steps are needed: +@item +@ref{1f5,,Stack Related Facilities} -@itemize @bullet -@item -Code instrumentation, requiring a full recompilation of the project with the -proper switches. -@item -Execution of the program under the analysis conditions, i.e. with the desired -input. -@item -Analysis of the results using the @code{gprof} tool. +@item +@ref{1f6,,Memory Management Issues} @end itemize -@noindent -The following sections detail the different steps, and indicate how -to interpret the results: @menu -* Compilation for profiling:: -* Program execution:: -* Running gprof:: -* Interpretation of profiling results:: -@end menu - -@node Compilation for profiling -@subsection Compilation for profiling -@cindex -pg -@cindex Profiling +* Running and Debugging Ada Programs:: +* Code Coverage and Profiling:: +* Improving Performance:: +* Overflow Check Handling in GNAT:: +* Performing Dimensionality Analysis in GNAT:: +* Stack Related Facilities:: +* Memory Management Issues:: -In order to profile a program the first step is to tell the compiler -to generate the necessary profiling information. The compiler switch to be used -is @code{-pg}, which must be added to other compilation switches. This -switch needs to be specified both during compilation and link stages, and can -be specified once when using gnatmake: - -@smallexample -gnatmake -f -pg -P my_project -@end smallexample - -@noindent -Note that only the objects that were compiled with the @samp{-pg} switch will -be profiled; if you need to profile your whole project, use the @samp{-f} -gnatmake switch to force full recompilation. - -@node Program execution -@subsection Program execution - -@noindent -Once the program has been compiled for profiling, you can run it as usual. - -The only constraint imposed by profiling is that the program must terminate -normally. An interrupted program (via a Ctrl-C, kill, etc.) will not be -properly analyzed. - -Once the program completes execution, a data file called @file{gmon.out} is -generated in the directory where the program was launched from. If this file -already exists, it will be overwritten. - -@node Running gprof -@subsection Running gprof - -@noindent -The @code{gprof} tool is called as follow: - -@smallexample -gprof my_prog gmon.out -@end smallexample - -@noindent -or simpler: - -@smallexample -gprof my_prog -@end smallexample - -@noindent -The complete form of the gprof command line is the following: - -@smallexample -gprof [switches] [executable [data-file]] -@end smallexample - -@noindent -@code{gprof} supports numerous switch. The order of these -switch does not matter. The full list of options can be found in -the GNU Profiler User's Guide documentation that comes with this documentation. - -The following is the subset of those switches that is most relevant: - -@table @option - -@item --demangle[=@var{style}] -@itemx --no-demangle -@cindex @option{--demangle} (@code{gprof}) -These options control whether symbol names should be demangled when -printing output. The default is to demangle C++ symbols. The -@code{--no-demangle} option may be used to turn off demangling. Different -compilers have different mangling styles. The optional demangling style -argument can be used to choose an appropriate demangling style for your -compiler, in particular Ada symbols generated by GNAT can be demangled using -@code{--demangle=gnat}. - -@item -e @var{function_name} -@cindex @option{-e} (@code{gprof}) -The @samp{-e @var{function}} option tells @code{gprof} not to print -information about the function @var{function_name} (and its -children@dots{}) in the call graph. The function will still be listed -as a child of any functions that call it, but its index number will be -shown as @samp{[not printed]}. More than one @samp{-e} option may be -given; only one @var{function_name} may be indicated with each @samp{-e} -option. - -@item -E @var{function_name} -@cindex @option{-E} (@code{gprof}) -The @code{-E @var{function}} option works like the @code{-e} option, but -execution time spent in the function (and children who were not called from -anywhere else), will not be used to compute the percentages-of-time for -the call graph. More than one @samp{-E} option may be given; only one -@var{function_name} may be indicated with each @samp{-E} option. - -@item -f @var{function_name} -@cindex @option{-f} (@code{gprof}) -The @samp{-f @var{function}} option causes @code{gprof} to limit the -call graph to the function @var{function_name} and its children (and -their children@dots{}). More than one @samp{-f} option may be given; -only one @var{function_name} may be indicated with each @samp{-f} -option. - -@item -F @var{function_name} -@cindex @option{-F} (@code{gprof}) -The @samp{-F @var{function}} option works like the @code{-f} option, but -only time spent in the function and its children (and their -children@dots{}) will be used to determine total-time and -percentages-of-time for the call graph. More than one @samp{-F} option -may be given; only one @var{function_name} may be indicated with each -@samp{-F} option. The @samp{-F} option overrides the @samp{-E} option. - -@end table - -@node Interpretation of profiling results -@subsection Interpretation of profiling results +@end menu -@noindent +@node Running and Debugging Ada Programs,Code Coverage and Profiling,,GNAT and Program Execution +@anchor{gnat_ugn/gnat_and_program_execution id2}@anchor{1f0}@anchor{gnat_ugn/gnat_and_program_execution running-and-debugging-ada-programs}@anchor{26} +@section Running and Debugging Ada Programs -The results of the profiling analysis are represented by two arrays: the -'flat profile' and the 'call graph'. Full documentation of those outputs -can be found in the GNU Profiler User's Guide. -The flat profile shows the time spent in each function of the program, and how -many time it has been called. This allows you to locate easily the most -time-consuming functions. +@geindex Debugging -The call graph shows, for each subprogram, the subprograms that call it, -and the subprograms that it calls. It also provides an estimate of the time -spent in each of those callers/called subprograms. +This section discusses how to debug Ada programs. -@c ****************************** -@node Running and Debugging Ada Programs -@chapter Running and Debugging Ada Programs -@cindex Debugging +An incorrect Ada program may be handled in three ways by the GNAT compiler: -@noindent -This chapter discusses how to debug Ada programs. -An incorrect Ada program may be handled in three ways by the GNAT compiler: +@itemize * -@enumerate -@item +@item The illegality may be a violation of the static semantics of Ada. In that case GNAT diagnoses the constructs in the program that are illegal. It is then a straightforward matter for the user to modify those parts of the program. -@item +@item The illegality may be a violation of the dynamic semantics of Ada. In that case the program compiles and executes, but may generate incorrect results, or may terminate abnormally with some exception. -@item +@item When presented with a program that contains convoluted errors, GNAT itself may terminate abnormally without providing full diagnostics on the incorrect user program. -@end enumerate +@end itemize + +@geindex Debugger + +@geindex gdb @menu -* The GNAT Debugger GDB:: -* Running GDB:: -* Introduction to GDB Commands:: -* Using Ada Expressions:: -* Calling User-Defined Subprograms:: -* Using the Next Command in a Function:: -* Ada Exceptions:: -* Ada Tasks:: -* Debugging Generic Units:: -* Remote Debugging with gdbserver:: -* GNAT Abnormal Termination or Failure to Terminate:: -* Naming Conventions for GNAT Source Files:: -* Getting Internal Debugging Information:: -* Stack Traceback:: +* The GNAT Debugger GDB:: +* Running GDB:: +* Introduction to GDB Commands:: +* Using Ada Expressions:: +* Calling User-Defined Subprograms:: +* Using the next Command in a Function:: +* Stopping When Ada Exceptions Are Raised:: +* Ada Tasks:: +* Debugging Generic Units:: +* Remote Debugging with gdbserver:: +* GNAT Abnormal Termination or Failure to Terminate:: +* Naming Conventions for GNAT Source Files:: +* Getting Internal Debugging Information:: +* Stack Traceback:: + @end menu -@cindex Debugger -@findex gdb +@node The GNAT Debugger GDB,Running GDB,,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution the-gnat-debugger-gdb}@anchor{1f7}@anchor{gnat_ugn/gnat_and_program_execution id3}@anchor{1f8} +@subsection The GNAT Debugger GDB -@node The GNAT Debugger GDB -@section The GNAT Debugger GDB -@noindent -@code{GDB} is a general purpose, platform-independent debugger that -can be used to debug mixed-language programs compiled with @command{gcc}, +@cite{GDB} is a general purpose, platform-independent debugger that +can be used to debug mixed-language programs compiled with @emph{gcc}, and in particular is capable of debugging Ada programs compiled with -GNAT. The latest versions of @code{GDB} are Ada-aware and can handle +GNAT. The latest versions of @cite{GDB} are Ada-aware and can handle complex Ada data structures. -@xref{Top,, Debugging with GDB, gdb, Debugging with GDB}, -for full details on the usage of @code{GDB}, including a section on +See @cite{Debugging with GDB}, +for full details on the usage of @cite{GDB}, including a section on its usage on programs. This manual should be consulted for full details. The section that follows is a brief introduction to the -philosophy and use of @code{GDB}. +philosophy and use of @cite{GDB}. When GNAT programs are compiled, the compiler optionally writes debugging information into the generated object file, including information on @@ -20834,7 +25089,7 @@ separate from the generated code. It makes the object files considerably larger, but it does not add to the size of the actual executable that will be loaded into memory, and has no impact on run-time performance. The generation of debug information is triggered by the use of the --g switch in the @command{gcc} or @command{gnatmake} command +-g switch in the @emph{gcc} or @emph{gnatmake} command used to carry out the compilations. It is important to emphasize that the use of these options does not change the generated code. @@ -20846,7 +25101,7 @@ details about Ada types and variables to be encoded into these standard C formats. Details of this encoding scheme may be found in the file exp_dbug.ads in the GNAT source distribution. However, the details of this encoding are, in general, of no interest to a user, -since @code{GDB} automatically performs the necessary decoding. +since @cite{GDB} automatically performs the necessary decoding. When a program is bound and linked, the debugging information is collected from the object files, and stored in the executable image of @@ -20856,219 +25111,315 @@ the executable program itself. Furthermore, if this program is run in the normal manner, it runs exactly as if the debug information were not present, and takes no more actual memory. -However, if the program is run under control of @code{GDB}, the +However, if the program is run under control of @cite{GDB}, the debugger is activated. The image of the program is loaded, at which point it is ready to run. If a run command is given, then the program -will run exactly as it would have if @code{GDB} were not present. This -is a crucial part of the @code{GDB} design philosophy. @code{GDB} is +will run exactly as it would have if @cite{GDB} were not present. This +is a crucial part of the @cite{GDB} design philosophy. @cite{GDB} is entirely non-intrusive until a breakpoint is encountered. If no breakpoint is ever hit, the program will run exactly as it would if no -debugger were present. When a breakpoint is hit, @code{GDB} accesses +debugger were present. When a breakpoint is hit, @cite{GDB} accesses the debugging information and can respond to user commands to inspect variables, and more generally to report on the state of execution. -@c ************** -@node Running GDB -@section Running GDB +@node Running GDB,Introduction to GDB Commands,The GNAT Debugger GDB,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution id4}@anchor{1f9}@anchor{gnat_ugn/gnat_and_program_execution running-gdb}@anchor{1fa} +@subsection Running GDB + -@noindent This section describes how to initiate the debugger. -@c The above sentence is really just filler, but it was otherwise -@c clumsy to get the first paragraph nonindented given the conditional -@c nature of the description -The debugger can be launched from a @code{GPS} menu or +The debugger can be launched from a @cite{GPS} menu or directly from the command line. The description below covers the latter use. -All the commands shown can be used in the @code{GPS} debug console window, +All the commands shown can be used in the @cite{GPS} debug console window, but there are usually more GUI-based ways to achieve the same effect. -The command to run @code{GDB} is +The command to run @cite{GDB} is + +@quotation -@smallexample +@example $ gdb program -@end smallexample +@end example +@end quotation -@noindent -where @code{program} is the name of the executable file. This +where @cite{program} is the name of the executable file. This activates the debugger and results in a prompt for debugger commands. -The simplest command is simply @code{run}, which causes the program to run +The simplest command is simply @cite{run}, which causes the program to run exactly as if the debugger were not present. The following section -describes some of the additional commands that can be given to @code{GDB}. +describes some of the additional commands that can be given to @cite{GDB}. -@c ******************************* -@node Introduction to GDB Commands -@section Introduction to GDB Commands +@node Introduction to GDB Commands,Using Ada Expressions,Running GDB,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution introduction-to-gdb-commands}@anchor{1fb}@anchor{gnat_ugn/gnat_and_program_execution id5}@anchor{1fc} +@subsection Introduction to GDB Commands -@noindent -@code{GDB} contains a large repertoire of commands. @xref{Top,, -Debugging with GDB, gdb, Debugging with GDB}, -for extensive documentation on the use + +@cite{GDB} contains a large repertoire of commands. +See @cite{Debugging with GDB} for extensive documentation on the use of these commands, together with examples of their use. Furthermore, -the command @command{help} invoked from within GDB activates a simple help +the command @emph{help} invoked from within GDB activates a simple help facility which summarizes the available commands and their options. In this section we summarize a few of the most commonly -used commands to give an idea of what @code{GDB} is about. You should create +used commands to give an idea of what @cite{GDB} is about. You should create a simple program with debugging information and experiment with the use of -these @code{GDB} commands on the program as you read through the +these @cite{GDB} commands on the program as you read through the following section. -@table @code -@item set args @var{arguments} -The @var{arguments} list above is a list of arguments to be passed to + +@itemize * + +@item + +@table @asis + +@item @emph{set args `arguments`} + +The @cite{arguments} list above is a list of arguments to be passed to the program on a subsequent run command, just as though the arguments -had been entered on a normal invocation of the program. The @code{set args} +had been entered on a normal invocation of the program. The @cite{set args} command is not needed if the program does not require arguments. +@end table -@item run -The @code{run} command causes execution of the program to start from +@item + +@table @asis + +@item @emph{run} + +The @cite{run} command causes execution of the program to start from the beginning. If the program is already running, that is to say if you are currently positioned at a breakpoint, then a prompt will ask for confirmation that you want to abandon the current execution and restart. +@end table + +@item + +@table @asis + +@item @emph{breakpoint `location`} -@item breakpoint @var{location} The breakpoint command sets a breakpoint, that is to say a point at which -execution will halt and @code{GDB} will await further -commands. @var{location} is -either a line number within a file, given in the format @code{file:linenumber}, +execution will halt and @cite{GDB} will await further +commands. @cite{location} is +either a line number within a file, given in the format @cite{file:linenumber}, or it is the name of a subprogram. If you request that a breakpoint be set on a subprogram that is overloaded, a prompt will ask you to specify on which of those subprograms you want to breakpoint. You can also specify that all of them should be breakpointed. If the program is run and execution encounters the breakpoint, then the program -stops and @code{GDB} signals that the breakpoint was encountered by +stops and @cite{GDB} signals that the breakpoint was encountered by printing the line of code before which the program is halted. +@end table + +@item + +@table @asis + +@item @emph{catch exception `name`} -@item catch exception @var{name} This command causes the program execution to stop whenever exception -@var{name} is raised. If @var{name} is omitted, then the execution is +@cite{name} is raised. If @cite{name} is omitted, then the execution is suspended when any exception is raised. +@end table + +@item + +@table @asis + +@item @emph{print `expression`} -@item print @var{expression} This will print the value of the given expression. Most simple -Ada expression formats are properly handled by @code{GDB}, so the expression +Ada expression formats are properly handled by @cite{GDB}, so the expression can contain function calls, variables, operators, and attribute references. +@end table + +@item + +@table @asis + +@item @emph{continue} -@item continue Continues execution following a breakpoint, until the next breakpoint or the termination of the program. +@end table + +@item + +@table @asis + +@item @emph{step} -@item step Executes a single line after a breakpoint. If the next statement is a subprogram call, execution continues into (the first statement of) the called subprogram. +@end table + +@item + +@table @asis + +@item @emph{next} -@item next Executes a single line. If this line is a subprogram call, executes and returns from the call. +@end table + +@item + +@table @asis + +@item @emph{list} -@item list Lists a few lines around the current source location. In practice, it is usually more convenient to have a separate edit window open with the relevant source file displayed. Successive applications of this command print subsequent lines. The command can be given an argument which is a line number, in which case it displays a few lines around the specified one. +@end table + +@item + +@table @asis + +@item @emph{backtrace} -@item backtrace Displays a backtrace of the call chain. This command is typically used after a breakpoint has occurred, to examine the sequence of calls that leads to the current breakpoint. The display includes one line for each activation record (frame) corresponding to an active subprogram. +@end table + +@item + +@table @asis + +@item @emph{up} -@item up -At a breakpoint, @code{GDB} can display the values of variables local -to the current frame. The command @code{up} can be used to +At a breakpoint, @cite{GDB} can display the values of variables local +to the current frame. The command @cite{up} can be used to examine the contents of other active frames, by moving the focus up the stack, that is to say from callee to caller, one frame at a time. +@end table + +@item + +@table @asis -@item down -Moves the focus of @code{GDB} down from the frame currently being +@item @emph{down} + +Moves the focus of @cite{GDB} down from the frame currently being examined to the frame of its callee (the reverse of the previous command), +@end table + +@item + +@table @asis + +@item @emph{frame `n`} -@item frame @var{n} Inspect the frame with the given number. The value 0 denotes the frame of the current breakpoint, that is to say the top of the call stack. +@end table + +@item + +@table @asis + +@item @emph{kill} -@item kill Kills the child process in which the program is running under GDB. This may be useful for several purposes: -@itemize @bullet -@item + + +@itemize * + +@item It allows you to recompile and relink your program, since on many systems you cannot regenerate an executable file while it is running in a process. -@item + +@item You can run your program outside the debugger, on systems that do not permit executing a program outside GDB while breakpoints are set within GDB. -@item + +@item It allows you to debug a core dump rather than a running process. @end itemize @end table +@end itemize -@noindent The above list is a very short introduction to the commands that -@code{GDB} provides. Important additional capabilities, including conditional +@cite{GDB} provides. Important additional capabilities, including conditional breakpoints, the ability to execute command sequences on a breakpoint, the ability to debug at the machine instruction level and many other -features are described in detail in @ref{Top,, Debugging with GDB, gdb, -Debugging with GDB}. Note that most commands can be abbreviated +features are described in detail in @cite{Debugging with GDB}. +Note that most commands can be abbreviated (for example, c for continue, bt for backtrace). -@node Using Ada Expressions -@section Using Ada Expressions -@cindex Ada expressions +@node Using Ada Expressions,Calling User-Defined Subprograms,Introduction to GDB Commands,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution id6}@anchor{1fd}@anchor{gnat_ugn/gnat_and_program_execution using-ada-expressions}@anchor{1fe} +@subsection Using Ada Expressions -@noindent -@code{GDB} supports a fairly large subset of Ada expression syntax, with some + +@geindex Ada expressions (in gdb) + +@cite{GDB} supports a fairly large subset of Ada expression syntax, with some extensions. The philosophy behind the design of this subset is -@itemize @bullet -@item -That @code{GDB} should provide basic literals and access to operations for +@quotation + + +@itemize * + +@item +That @cite{GDB} should provide basic literals and access to operations for arithmetic, dereferencing, field selection, indexing, and subprogram calls, leaving more sophisticated computations to subprograms written into the -program (which therefore may be called from @code{GDB}). +program (which therefore may be called from @cite{GDB}). -@item +@item That type safety and strict adherence to Ada language restrictions -are not particularly important to the @code{GDB} user. +are not particularly relevant in a debugging context. -@item -That brevity is important to the @code{GDB} user. +@item +That brevity is important to the @cite{GDB} user. @end itemize +@end quotation -@noindent Thus, for brevity, the debugger acts as if there were -implicit @code{with} and @code{use} clauses in effect for all user-written +implicit @cite{with} and @cite{use} clauses in effect for all user-written packages, thus making it unnecessary to fully qualify most names with their packages, regardless of context. Where this causes ambiguity, -@code{GDB} asks the user's intent. +@cite{GDB} asks the user's intent. -For details on the supported Ada syntax, see @ref{Top,, Debugging with -GDB, gdb, Debugging with GDB}. +For details on the supported Ada syntax, see @cite{Debugging with GDB}. -@node Calling User-Defined Subprograms -@section Calling User-Defined Subprograms +@node Calling User-Defined Subprograms,Using the next Command in a Function,Using Ada Expressions,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution id7}@anchor{1ff}@anchor{gnat_ugn/gnat_and_program_execution calling-user-defined-subprograms}@anchor{200} +@subsection Calling User-Defined Subprograms -@noindent -An important capability of @code{GDB} is the ability to call user-defined + +An important capability of @cite{GDB} is the ability to call user-defined subprograms while debugging. This is achieved simply by entering a subprogram call statement in the form: -@smallexample +@quotation + +@example call subprogram-name (parameters) -@end smallexample +@end example +@end quotation -@noindent -The keyword @code{call} can be omitted in the normal case where the -@code{subprogram-name} does not coincide with any of the predefined -@code{GDB} commands. +The keyword @cite{call} can be omitted in the normal case where the +@cite{subprogram-name} does not coincide with any of the predefined +@cite{GDB} commands. The effect is to invoke the given subprogram, passing it the list of parameters that is supplied. The parameters can be expressions and can include variables from the program being debugged. The subprogram must be defined -at the library level within your program, and @code{GDB} will call the +at the library level within your program, and @cite{GDB} will call the subprogram within the environment of your program execution (which means that the subprogram is free to access or even modify variables within your program). @@ -21078,7 +25429,7 @@ debugging routines that are tailored to particular data structures in your program. Such debugging routines can be written to provide a suitably high-level description of an abstract type, rather than a low-level dump of its physical layout. After all, the standard -@code{GDB print} command only knows the physical layout of your +@cite{GDB print} command only knows the physical layout of your types, not their abstract meaning. Debugging routines can provide information at the desired semantic level and are thus enormously useful. @@ -21086,7 +25437,7 @@ For example, when debugging GNAT itself, it is crucial to have access to the contents of the tree nodes used to represent the program internally. But tree nodes are represented simply by an integer value (which in turn is an index into a table of nodes). -Using the @code{print} command on a tree node would simply print this integer +Using the @cite{print} command on a tree node would simply print this integer value, which is not very useful. But the PN routine (defined in file treepr.adb in the GNAT sources) takes a tree node as input, and displays a useful high level representation of the tree node, which includes the @@ -21103,181 +25454,237 @@ address the array elements. In such a case, instead of trying to print the elements directly from GDB, you can write a callable procedure that prints the elements in the desired format. -@node Using the Next Command in a Function -@section Using the Next Command in a Function +@node Using the next Command in a Function,Stopping When Ada Exceptions Are Raised,Calling User-Defined Subprograms,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution using-the-next-command-in-a-function}@anchor{201}@anchor{gnat_ugn/gnat_and_program_execution id8}@anchor{202} +@subsection Using the @emph{next} Command in a Function -@noindent -When you use the @code{next} command in a function, the current source + +When you use the @cite{next} command in a function, the current source location will advance to the next statement as usual. A special case -arises in the case of a @code{return} statement. +arises in the case of a @cite{return} statement. -Part of the code for a return statement is the ``epilogue'' of the function. +Part of the code for a return statement is the 'epilogue' of the function. This is the code that returns to the caller. There is only one copy of this epilogue code, and it is typically associated with the last return statement in the function if there is more than one return. In some implementations, this epilogue is associated with the first statement of the function. -The result is that if you use the @code{next} command from a return +The result is that if you use the @cite{next} command from a return statement that is not the last return statement of the function you may see a strange apparent jump to the last return statement or to the start of the function. You should simply ignore this odd jump. The value returned is always that from the first return statement that was stepped through. -@node Ada Exceptions -@section Stopping when Ada Exceptions are Raised -@cindex Exceptions +@node Stopping When Ada Exceptions Are Raised,Ada Tasks,Using the next Command in a Function,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution stopping-when-ada-exceptions-are-raised}@anchor{203}@anchor{gnat_ugn/gnat_and_program_execution id9}@anchor{204} +@subsection Stopping When Ada Exceptions Are Raised + + +@geindex Exceptions (in gdb) -@noindent You can set catchpoints that stop the program execution when your program raises selected exceptions. -@table @code -@item catch exception + +@itemize * + +@item + +@table @asis + +@item @emph{catch exception} + Set a catchpoint that stops execution whenever (any task in the) program raises any exception. +@end table + +@item + +@table @asis + +@item @emph{catch exception `name`} -@item catch exception @var{name} Set a catchpoint that stops execution whenever (any task in the) program -raises the exception @var{name}. +raises the exception @cite{name}. +@end table + +@item + +@table @asis + +@item @emph{catch exception unhandled} -@item catch exception unhandled Set a catchpoint that stops executing whenever (any task in the) program raises an exception for which there is no handler. +@end table + +@item + +@table @asis + +@item @emph{info exceptions}, @emph{info exceptions `regexp`} -@item info exceptions -@itemx info exceptions @var{regexp} -The @code{info exceptions} command permits the user to examine all defined -exceptions within Ada programs. With a regular expression, @var{regexp}, as -argument, prints out only those exceptions whose name matches @var{regexp}. +The @cite{info exceptions} command permits the user to examine all defined +exceptions within Ada programs. With a regular expression, @cite{regexp}, as +argument, prints out only those exceptions whose name matches @cite{regexp}. @end table +@end itemize + +@geindex Tasks (in gdb) -@node Ada Tasks -@section Ada Tasks -@cindex Tasks +@node Ada Tasks,Debugging Generic Units,Stopping When Ada Exceptions Are Raised,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution ada-tasks}@anchor{205}@anchor{gnat_ugn/gnat_and_program_execution id10}@anchor{206} +@subsection Ada Tasks -@noindent -@code{GDB} allows the following task-related commands: -@table @code -@item info tasks +@cite{GDB} allows the following task-related commands: + + +@itemize * + +@item + +@table @asis + +@item @emph{info tasks} + This command shows a list of current Ada tasks, as in the following example: -@smallexample -@iftex -@leftskip=0cm -@end iftex +@example (gdb) info tasks ID TID P-ID Thread Pri State Name 1 8088000 0 807e000 15 Child Activation Wait main_task 2 80a4000 1 80ae000 15 Accept/Select Wait b 3 809a800 1 80a4800 15 Child Activation Wait a * 4 80ae800 3 80b8000 15 Running c -@end smallexample +@end example -@noindent In this listing, the asterisk before the first task indicates it to be the currently running task. The first column lists the task ID that is used to refer to tasks in the following commands. +@end table +@end itemize + +@geindex Breakpoints and tasks + + +@itemize * -@item break @var{linespec} task @var{taskid} -@itemx break @var{linespec} task @var{taskid} if @dots{} -@cindex Breakpoints and tasks -These commands are like the @code{break @dots{} thread @dots{}}. -@var{linespec} specifies source lines. +@item +@emph{break `linespec` task `taskid`}, @emph{break `linespec` task `taskid` if ...} -Use the qualifier @samp{task @var{taskid}} with a breakpoint command -to specify that you only want @code{GDB} to stop the program when a -particular Ada task reaches this breakpoint. @var{taskid} is one of the -numeric task identifiers assigned by @code{GDB}, shown in the first -column of the @samp{info tasks} display. +@quotation + +These commands are like the @cite{break ... thread ...}. +@cite{linespec} specifies source lines. -If you do not specify @samp{task @var{taskid}} when you set a +Use the qualifier @code{task @emph{taskid}} with a breakpoint command +to specify that you only want @cite{GDB} to stop the program when a +particular Ada task reaches this breakpoint. @cite{taskid} is one of the +numeric task identifiers assigned by @cite{GDB}, shown in the first +column of the @code{info tasks} display. + +If you do not specify @code{task @emph{taskid}} when you set a breakpoint, the breakpoint applies to @emph{all} tasks of your program. -You can use the @code{task} qualifier on conditional breakpoints as -well; in this case, place @samp{task @var{taskid}} before the -breakpoint condition (before the @code{if}). +You can use the @cite{task} qualifier on conditional breakpoints as +well; in this case, place @code{task @emph{taskid}} before the +breakpoint condition (before the @cite{if}). +@end quotation +@end itemize + +@geindex Task switching (in gdb) + + +@itemize * -@item task @var{taskno} -@cindex Task switching +@item +@emph{task `taskno`} -This command allows switching to the task referred by @var{taskno}. In +@quotation + +This command allows switching to the task referred by @cite{taskno}. In particular, this allows browsing of the backtrace of the specified task. It is advisable to switch back to the original task before continuing execution otherwise the scheduling of the program may be perturbed. -@end table +@end quotation +@end itemize -@noindent For more detailed information on the tasking support, -see @ref{Top,, Debugging with GDB, gdb, Debugging with GDB}. +see @cite{Debugging with GDB}. + +@geindex Debugging Generic Units + +@geindex Generics + +@node Debugging Generic Units,Remote Debugging with gdbserver,Ada Tasks,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution debugging-generic-units}@anchor{207}@anchor{gnat_ugn/gnat_and_program_execution id11}@anchor{208} +@subsection Debugging Generic Units -@node Debugging Generic Units -@section Debugging Generic Units -@cindex Debugging Generic Units -@cindex Generics -@noindent GNAT always uses code expansion for generic instantiation. This means that each time an instantiation occurs, a complete copy of the original code is made, with appropriate substitutions of formals by actuals. It is not possible to refer to the original generic entities in -@code{GDB}, but it is always possible to debug a particular instance of +@cite{GDB}, but it is always possible to debug a particular instance of a generic, by using the appropriate expanded names. For example, if we have -@smallexample @c ada -@group -@cartouche -@b{procedure} g @b{is} +@quotation - @b{generic} @b{package} k @b{is} - @b{procedure} kp (v1 : @b{in} @b{out} integer); - @b{end} k; +@example +procedure g is - @b{package} @b{body} k @b{is} - @b{procedure} kp (v1 : @b{in} @b{out} integer) @b{is} - @b{begin} + generic package k is + procedure kp (v1 : in out integer); + end k; + + package body k is + procedure kp (v1 : in out integer) is + begin v1 := v1 + 1; - @b{end} kp; - @b{end} k; + end kp; + end k; - @b{package} k1 @b{is} @b{new} k; - @b{package} k2 @b{is} @b{new} k; + package k1 is new k; + package k2 is new k; var : integer := 1; -@b{begin} +begin k1.kp (var); k2.kp (var); k1.kp (var); k2.kp (var); -@b{end}; -@end cartouche -@end group -@end smallexample +end; +@end example +@end quotation -@noindent Then to break on a call to procedure kp in the k2 instance, simply use the command: -@smallexample +@quotation + +@example (gdb) break g.k2.kp -@end smallexample +@end example +@end quotation -@noindent When the breakpoint occurs, you can step through the code of the instance in the normal manner and examine the values of local variables, as for other units. -@node Remote Debugging with gdbserver -@section Remote Debugging with gdbserver -@cindex Remote Debugging with gdbserver +@geindex Remote Debugging with gdbserver + +@node Remote Debugging with gdbserver,GNAT Abnormal Termination or Failure to Terminate,Debugging Generic Units,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution remote-debugging-with-gdbserver}@anchor{209}@anchor{gnat_ugn/gnat_and_program_execution id12}@anchor{20a} +@subsection Remote Debugging with gdbserver + -@noindent On platforms where gdbserver is supported, it is possible to use this tool to debug your application remotely. This can be useful in situations where the program needs to be run on a target host that is different @@ -21290,18 +25697,23 @@ at its entry point, waiting for a debugger to connect to it. The following commands starts an application and tells gdbserver to wait for a connection with the debugger on localhost port 4444. -@smallexample +@quotation + +@example $ gdbserver localhost:4444 program Process program created; pid = 5685 Listening on port 4444 -@end smallexample +@end example +@end quotation Once gdbserver has started listening, we can tell the debugger to establish a connection with this gdbserver, and then start the same debugging session as if the program was being debugged on the same host, directly under the control of GDB. -@smallexample +@quotation + +@example $ gdb program (gdb) target remote targethost:4444 Remote debugging using targethost:4444 @@ -21313,21 +25725,24 @@ Continuing. Breakpoint 1, foo () at foo.adb:4 4 end foo; -@end smallexample +@end example +@end quotation It is also possible to use gdbserver to attach to an already running program, in which case the execution of that program is simply suspended until the connection between the debugger and gdbserver is established. -For more information on how to use gdbserver, @ref{Top, Server, Using -the gdbserver Program, gdb, Debugging with GDB}. @value{EDITION} provides support -for gdbserver on x86-linux, x86-windows and x86_64-linux. +For more information on how to use gdbserver, see the @emph{Using the gdbserver Program} +section in @cite{Debugging with GDB}. +GNAT provides support for gdbserver on x86-linux, x86-windows and x86_64-linux. + +@geindex Abnormal Termination or Failure to Terminate + +@node GNAT Abnormal Termination or Failure to Terminate,Naming Conventions for GNAT Source Files,Remote Debugging with gdbserver,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution gnat-abnormal-termination-or-failure-to-terminate}@anchor{20b}@anchor{gnat_ugn/gnat_and_program_execution id13}@anchor{20c} +@subsection GNAT Abnormal Termination or Failure to Terminate -@node GNAT Abnormal Termination or Failure to Terminate -@section GNAT Abnormal Termination or Failure to Terminate -@cindex GNAT Abnormal Termination or Failure to Terminate -@noindent When presented with programs that contain serious errors in syntax or semantics, GNAT may on rare occasions experience problems in operation, such @@ -21342,127 +25757,141 @@ The following strategies are presented in increasing order of difficulty, corresponding to your experience in using GNAT and your familiarity with compiler internals. -@enumerate -@item -Run @command{gcc} with the @option{-gnatf}. This first + +@itemize * + +@item +Run @emph{gcc} with the @emph{-gnatf}. This first switch causes all errors on a given line to be reported. In its absence, only the first error on a line is displayed. -The @option{-gnatdO} switch causes errors to be displayed as soon as they +The @emph{-gnatdO} switch causes errors to be displayed as soon as they are encountered, rather than after compilation is terminated. If GNAT terminates prematurely or goes into an infinite loop, the last error message displayed may help to pinpoint the culprit. -@item -Run @command{gcc} with the @option{-v (verbose)} switch. In this -mode, @command{gcc} produces ongoing information about the progress of the +@item +Run @emph{gcc} with the @emph{-v (verbose)} switch. In this +mode, @emph{gcc} produces ongoing information about the progress of the compilation and provides the name of each procedure as code is generated. This switch allows you to find which Ada procedure was being compiled when it encountered a code generation problem. +@end itemize -@item -@cindex @option{-gnatdc} switch -Run @command{gcc} with the @option{-gnatdc} switch. This is a GNAT specific -switch that does for the front-end what @option{-v} does +@geindex -gnatdc switch + + +@itemize * + +@item +Run @emph{gcc} with the @emph{-gnatdc} switch. This is a GNAT specific +switch that does for the front-end what @emph{-v} does for the back end. The system prints the name of each unit, either a compilation unit or nested unit, as it is being analyzed. -@item + +@item Finally, you can start -@code{gdb} directly on the @code{gnat1} executable. @code{gnat1} is the +@cite{gdb} directly on the @cite{gnat1} executable. @cite{gnat1} is the front-end of GNAT, and can be run independently (normally it is just -called from @command{gcc}). You can use @code{gdb} on @code{gnat1} as you -would on a C program (but @pxref{The GNAT Debugger GDB} for caveats). The -@code{where} command is the first line of attack; the variable -@code{lineno} (seen by @code{print lineno}), used by the second phase of -@code{gnat1} and by the @command{gcc} backend, indicates the source line at -which the execution stopped, and @code{input_file name} indicates the name of +called from @emph{gcc}). You can use @cite{gdb} on @cite{gnat1} as you +would on a C program (but @ref{1f7,,The GNAT Debugger GDB} for caveats). The +@cite{where} command is the first line of attack; the variable +@cite{lineno} (seen by @cite{print lineno}), used by the second phase of +@cite{gnat1} and by the @emph{gcc} backend, indicates the source line at +which the execution stopped, and @cite{input_file name} indicates the name of the source file. -@end enumerate +@end itemize + +@node Naming Conventions for GNAT Source Files,Getting Internal Debugging Information,GNAT Abnormal Termination or Failure to Terminate,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution naming-conventions-for-gnat-source-files}@anchor{20d}@anchor{gnat_ugn/gnat_and_program_execution id14}@anchor{20e} +@subsection Naming Conventions for GNAT Source Files -@node Naming Conventions for GNAT Source Files -@section Naming Conventions for GNAT Source Files -@noindent In order to examine the workings of the GNAT system, the following brief description of its organization may be helpful: -@itemize @bullet -@item -Files with prefix @file{sc} contain the lexical scanner. -@item -All files prefixed with @file{par} are components of the parser. The +@itemize * + +@item +Files with prefix @code{sc} contain the lexical scanner. + +@item +All files prefixed with @code{par} are components of the parser. The numbers correspond to chapters of the Ada Reference Manual. For example, -parsing of select statements can be found in @file{par-ch9.adb}. +parsing of select statements can be found in @code{par-ch9.adb}. -@item -All files prefixed with @file{sem} perform semantic analysis. The +@item +All files prefixed with @code{sem} perform semantic analysis. The numbers correspond to chapters of the Ada standard. For example, all -issues involving context clauses can be found in @file{sem_ch10.adb}. In +issues involving context clauses can be found in @code{sem_ch10.adb}. In addition, some features of the language require sufficient special processing to justify their own semantic files: sem_aggr for aggregates, sem_disp for dynamic dispatching, etc. -@item -All files prefixed with @file{exp} perform normalization and +@item +All files prefixed with @code{exp} perform normalization and expansion of the intermediate representation (abstract syntax tree, or AST). these files use the same numbering scheme as the parser and semantics files. For example, the construction of record initialization procedures is done in -@file{exp_ch3.adb}. +@code{exp_ch3.adb}. -@item -The files prefixed with @file{bind} implement the binder, which +@item +The files prefixed with @code{bind} implement the binder, which verifies the consistency of the compilation, determines an order of elaboration, and generates the bind file. -@item -The files @file{atree.ads} and @file{atree.adb} detail the low-level +@item +The files @code{atree.ads} and @code{atree.adb} detail the low-level data structures used by the front-end. -@item -The files @file{sinfo.ads} and @file{sinfo.adb} detail the structure of +@item +The files @code{sinfo.ads} and @code{sinfo.adb} detail the structure of the abstract syntax tree as produced by the parser. -@item -The files @file{einfo.ads} and @file{einfo.adb} detail the attributes of +@item +The files @code{einfo.ads} and @code{einfo.adb} detail the attributes of all entities, computed during semantic analysis. -@item +@item Library management issues are dealt with in files with prefix -@file{lib}. +@code{lib}. -@item -@findex Ada -@cindex Annex A -Ada files with the prefix @file{a-} are children of @code{Ada}, as +@geindex Annex A (in Ada Reference Manual) + +@item +Ada files with the prefix @code{a-} are children of @cite{Ada}, as defined in Annex A. -@item -@findex Interfaces -@cindex Annex B -Files with prefix @file{i-} are children of @code{Interfaces}, as +@geindex Annex B (in Ada reference Manual) + +@item +Files with prefix @code{i-} are children of @cite{Interfaces}, as defined in Annex B. -@item -@findex System -Files with prefix @file{s-} are children of @code{System}. This includes +@geindex System (package in Ada Reference Manual) + +@item +Files with prefix @code{s-} are children of @cite{System}. This includes both language-defined children and GNAT run-time routines. -@item -@findex GNAT -Files with prefix @file{g-} are children of @code{GNAT}. These are useful +@geindex GNAT (package) + +@item +Files with prefix @code{g-} are children of @cite{GNAT}. These are useful general-purpose packages, fully documented in their specs. All -the other @file{.c} files are modifications of common @command{gcc} files. +the other @code{.c} files are modifications of common @emph{gcc} files. @end itemize -@node Getting Internal Debugging Information -@section Getting Internal Debugging Information +@node Getting Internal Debugging Information,Stack Traceback,Naming Conventions for GNAT Source Files,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution id15}@anchor{20f}@anchor{gnat_ugn/gnat_and_program_execution getting-internal-debugging-information}@anchor{210} +@subsection Getting Internal Debugging Information + -@noindent Most compilers have internal debugging switches and modes. GNAT does also, except GNAT internal debugging switches and modes are not secret. A summary and full description of all the compiler and binder -debug flags are in the file @file{debug.adb}. You must obtain the +debug flags are in the file @code{debug.adb}. You must obtain the sources of the compiler to see the full detailed effects of these flags. The switches that print the source of the program (reconstructed from @@ -21476,17 +25905,21 @@ For example, constraint checks are indicated, complex aggregates are replaced with loops and assignments, and tasking primitives are replaced with run-time calls. -@node Stack Traceback -@section Stack Traceback -@cindex traceback -@cindex stack traceback -@cindex stack unwinding +@geindex traceback + +@geindex stack traceback + +@geindex stack unwinding + +@node Stack Traceback,,Getting Internal Debugging Information,Running and Debugging Ada Programs +@anchor{gnat_ugn/gnat_and_program_execution stack-traceback}@anchor{211}@anchor{gnat_ugn/gnat_and_program_execution id16}@anchor{212} +@subsection Stack Traceback + -@noindent Traceback is a mechanism to display the sequence of subprogram calls that leads to a specified execution point in a program. Often (but not always) the execution point is an instruction at which an exception has been raised. -This mechanism is also known as @i{stack unwinding} because it obtains +This mechanism is also known as @emph{stack unwinding} because it obtains its information by scanning the run-time stack and recovering the activation records of all active subprograms. Stack unwinding is one of the most important tools for program debugging. @@ -21498,59 +25931,56 @@ from which we want to obtain the traceback. Note that there is no runtime performance penalty when stack traceback is enabled, and no exception is raised during program execution. +@geindex traceback +@geindex non-symbolic + @menu -* Non-Symbolic Traceback:: -* Symbolic Traceback:: +* Non-Symbolic Traceback:: +* Symbolic Traceback:: + @end menu -@node Non-Symbolic Traceback -@subsection Non-Symbolic Traceback -@cindex traceback, non-symbolic +@node Non-Symbolic Traceback,Symbolic Traceback,,Stack Traceback +@anchor{gnat_ugn/gnat_and_program_execution non-symbolic-traceback}@anchor{213}@anchor{gnat_ugn/gnat_and_program_execution id17}@anchor{214} +@subsubsection Non-Symbolic Traceback + -@noindent Note: this feature is not supported on all platforms. See -@file{GNAT.Traceback spec in g-traceb.ads} for a complete list of supported -platforms. +@code{GNAT.Traceback} spec in @code{g-traceb.ads} +for a complete list of supported platforms. -@menu -* Tracebacks From an Unhandled Exception:: -* Tracebacks From Exception Occurrences (non-symbolic):: -* Tracebacks From Anywhere in a Program (non-symbolic):: -@end menu +@subsubheading Tracebacks From an Unhandled Exception -@node Tracebacks From an Unhandled Exception -@subsubsection Tracebacks From an Unhandled Exception -@noindent A runtime non-symbolic traceback is a list of addresses of call instructions. -To enable this feature you must use the @option{-E} -@code{gnatbind}'s option. With this option a stack traceback is stored as part +To enable this feature you must use the @emph{-E} +@cite{gnatbind}'s option. With this option a stack traceback is stored as part of exception information. You can retrieve this information using the -@code{addr2line} tool. +@cite{addr2line} tool. Here is a simple example: -@smallexample @c ada -@cartouche -@b{procedure} STB @b{is} +@quotation + +@example +procedure STB is - @b{procedure} P1 @b{is} - @b{begin} - @b{raise} Constraint_Error; - @b{end} P1; + procedure P1 is + begin + raise Constraint_Error; + end P1; - @b{procedure} P2 @b{is} - @b{begin} + procedure P2 is + begin P1; - @b{end} P2; + end P2; -@b{begin} +begin P2; -@b{end} STB; -@end cartouche -@end smallexample +end STB; +@end example -@smallexample +@example $ gnatmake stb -bargs -E $ stb @@ -21559,17 +25989,19 @@ Exception name: CONSTRAINT_ERROR Message: stb.adb:5 Call stack traceback locations: 0x401373 0x40138b 0x40139c 0x401335 0x4011c4 0x4011f1 0x77e892a4 -@end smallexample +@end example +@end quotation -@noindent As we see the traceback lists a sequence of addresses for the unhandled -exception @code{CONSTRAINT_ERROR} raised in procedure P1. It is easy to +exception @cite{CONSTRAINT_ERROR} raised in procedure P1. It is easy to guess that this exception come from procedure P1. To translate these addresses into the source lines where the calls appear, the -@code{addr2line} tool, described below, is invaluable. The use of this tool +@cite{addr2line} tool, described below, is invaluable. The use of this tool requires the program to be compiled with debug information. -@smallexample +@quotation + +@example $ gnatmake -g stb -bargs -E $ stb @@ -21586,24 +26018,40 @@ $ addr2line --exe=stb 0x401373 0x40138b 0x40139c 0x401335 0x4011c4 0040138B at d:/stb/stb.adb:10 0040139C at d:/stb/stb.adb:14 00401335 at d:/stb/b~stb.adb:104 -004011C4 at /build/@dots{}/crt1.c:200 -004011F1 at /build/@dots{}/crt1.c:222 +004011C4 at /build/.../crt1.c:200 +004011F1 at /build/.../crt1.c:222 77E892A4 in ?? at ??:0 -@end smallexample +@end example +@end quotation + +The @cite{addr2line} tool has several other useful options: + +@quotation + + +@multitable {xxxxxxxxxxxxxxxxxxxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item -@noindent -The @code{addr2line} tool has several other useful options: +@code{--functions} + +@tab -@table @code -@item --functions to get the function name corresponding to any location -@item --demangle=gnat -to use the gnat decoding mode for the function names. Note that -for binutils version 2.9.x the option is simply @option{--demangle}. -@end table +@item + +@code{--demangle=gnat} -@smallexample +@tab + +to use the gnat decoding mode for the function names. +Note that for binutils version 2.9.x the option is +simply @code{--demangle}. + +@end multitable + + +@example $ addr2line --exe=stb --functions --demangle=gnat 0x401373 0x40138b 0x40139c 0x401335 0x4011c4 0x4011f1 @@ -21611,33 +26059,40 @@ $ addr2line --exe=stb --functions --demangle=gnat 0x401373 0x40138b 0040138B in stb.p2 at d:/stb/stb.adb:10 0040139C in stb at d:/stb/stb.adb:14 00401335 in main at d:/stb/b~stb.adb:104 -004011C4 in <__mingw_CRTStartup> at /build/@dots{}/crt1.c:200 -004011F1 in <mainCRTStartup> at /build/@dots{}/crt1.c:222 -@end smallexample +004011C4 in <__mingw_CRTStartup> at /build/.../crt1.c:200 +004011F1 in <mainCRTStartup> at /build/.../crt1.c:222 +@end example +@end quotation -@noindent From this traceback we can see that the exception was raised in -@file{stb.adb} at line 5, which was reached from a procedure call in -@file{stb.adb} at line 10, and so on. The @file{b~std.adb} is the binder file, +@code{stb.adb} at line 5, which was reached from a procedure call in +@code{stb.adb} at line 10, and so on. The @code{b~std.adb} is the binder file, which contains the call to the main program. -@xref{Running gnatbind}. The remaining entries are assorted runtime routines, +@ref{120,,Running gnatbind}. The remaining entries are assorted runtime routines, and the output will vary from platform to platform. -It is also possible to use @code{GDB} with these traceback addresses to debug +It is also possible to use @cite{GDB} with these traceback addresses to debug the program. For example, we can break at a given code location, as reported in the stack traceback: -@smallexample +@quotation + +@example $ gdb -nw stb -@noindent +@end example +@end quotation + Furthermore, this feature is not implemented inside Windows DLL. Only the non-symbolic traceback is reported in this case. +@quotation + +@example (gdb) break *0x401373 Breakpoint 1 at 0x401373: file stb.adb, line 5. -@end smallexample +@end example +@end quotation -@noindent It is important to note that the stack traceback addresses do not change when debug information is included. This is particularly useful because it makes it possible to release software without debug information (to @@ -21645,180 +26100,184 @@ minimize object size), get a field report that includes a stack traceback whenever an internal bug occurs, and then be able to retrieve the sequence of calls with the same program compiled with debug information. -@node Tracebacks From Exception Occurrences (non-symbolic) -@subsubsection Tracebacks From Exception Occurrences +@subsubheading Tracebacks From Exception Occurrences + -@noindent -Non-symbolic tracebacks are obtained by using the @option{-E} binder argument. +Non-symbolic tracebacks are obtained by using the @emph{-E} binder argument. The stack traceback is attached to the exception information string, and can be retrieved in an exception handler within the Ada program, by means of the -Ada facilities defined in @code{Ada.Exceptions}. Here is a simple example: +Ada facilities defined in @cite{Ada.Exceptions}. Here is a simple example: + +@quotation -@smallexample @c ada -@b{with} Ada.Text_IO; -@b{with} Ada.Exceptions; +@example +with Ada.Text_IO; +with Ada.Exceptions; -@b{procedure} STB @b{is} +procedure STB is - @b{use} Ada; - @b{use} Ada.Exceptions; + use Ada; + use Ada.Exceptions; - @b{procedure} P1 @b{is} + procedure P1 is K : Positive := 1; - @b{begin} + begin K := K - 1; - @b{exception} - @b{when} E : @b{others} => + exception + when E : others => Text_IO.Put_Line (Exception_Information (E)); - @b{end} P1; + end P1; - @b{procedure} P2 @b{is} - @b{begin} + procedure P2 is + begin P1; - @b{end} P2; + end P2; -@b{begin} +begin P2; -@b{end} STB; -@end smallexample +end STB; +@end example +@end quotation -@noindent This program will output: -@smallexample +@quotation + +@example $ stb Exception name: CONSTRAINT_ERROR Message: stb.adb:12 Call stack traceback locations: 0x4015e4 0x401633 0x401644 0x401461 0x4011c4 0x4011f1 0x77e892a4 -@end smallexample +@end example +@end quotation + +@subsubheading Tracebacks From Anywhere in a Program -@node Tracebacks From Anywhere in a Program (non-symbolic) -@subsubsection Tracebacks From Anywhere in a Program -@noindent It is also possible to retrieve a stack traceback from anywhere in a program. For this you need to -use the @code{GNAT.Traceback} API. This package includes a procedure called -@code{Call_Chain} that computes a complete stack traceback, as well as useful +use the @cite{GNAT.Traceback} API. This package includes a procedure called +@cite{Call_Chain} that computes a complete stack traceback, as well as useful display procedures described below. It is not necessary to use the -@option{-E gnatbind} option in this case, because the stack traceback mechanism +@emph{-E gnatbind} option in this case, because the stack traceback mechanism is invoked explicitly. -@noindent In the following example we compute a traceback at a specific location in -the program, and we display it using @code{GNAT.Debug_Utilities.Image} to +the program, and we display it using @cite{GNAT.Debug_Utilities.Image} to convert addresses to strings: -@smallexample @c ada -@b{with} Ada.Text_IO; -@b{with} GNAT.Traceback; -@b{with} GNAT.Debug_Utilities; +@quotation + +@example +with Ada.Text_IO; +with GNAT.Traceback; +with GNAT.Debug_Utilities; -@b{procedure} STB @b{is} +procedure STB is - @b{use} Ada; - @b{use} GNAT; - @b{use} GNAT.Traceback; + use Ada; + use GNAT; + use GNAT.Traceback; - @b{procedure} P1 @b{is} + procedure P1 is TB : Tracebacks_Array (1 .. 10); - --@i{ We are asking for a maximum of 10 stack frames.} + -- We are asking for a maximum of 10 stack frames. Len : Natural; - --@i{ Len will receive the actual number of stack frames returned.} - @b{begin} + -- Len will receive the actual number of stack frames returned. + begin Call_Chain (TB, Len); Text_IO.Put ("In STB.P1 : "); - @b{for} K @b{in} 1 .. Len @b{loop} + for K in 1 .. Len loop Text_IO.Put (Debug_Utilities.Image (TB (K))); Text_IO.Put (' '); - @b{end} @b{loop}; + end loop; Text_IO.New_Line; - @b{end} P1; + end P1; - @b{procedure} P2 @b{is} - @b{begin} + procedure P2 is + begin P1; - @b{end} P2; + end P2; -@b{begin} +begin P2; -@b{end} STB; -@end smallexample +end STB; +@end example -@smallexample +@example $ gnatmake -g stb $ stb In STB.P1 : 16#0040_F1E4# 16#0040_14F2# 16#0040_170B# 16#0040_171C# 16#0040_1461# 16#0040_11C4# 16#0040_11F1# 16#77E8_92A4# -@end smallexample +@end example +@end quotation -@noindent -You can then get further information by invoking the @code{addr2line} +You can then get further information by invoking the @cite{addr2line} tool as described earlier (note that the hexadecimal addresses -need to be specified in C format, with a leading ``0x''). +need to be specified in C format, with a leading '0x'). + +@geindex traceback +@geindex symbolic + +@node Symbolic Traceback,,Non-Symbolic Traceback,Stack Traceback +@anchor{gnat_ugn/gnat_and_program_execution id18}@anchor{215}@anchor{gnat_ugn/gnat_and_program_execution symbolic-traceback}@anchor{216} +@subsubsection Symbolic Traceback -@node Symbolic Traceback -@subsection Symbolic Traceback -@cindex traceback, symbolic -@noindent A symbolic traceback is a stack traceback in which procedure names are associated with each code location. -@noindent Note that this feature is not supported on all platforms. See -@file{GNAT.Traceback.Symbolic spec in g-trasym.ads} for a complete +@code{GNAT.Traceback.Symbolic} spec in @code{g-trasym.ads} for a complete list of currently supported platforms. -@noindent Note that the symbolic traceback requires that the program be compiled with debug information. If it is not compiled with debug information only the non-symbolic information will be valid. -@menu -* Tracebacks From Exception Occurrences (symbolic):: -* Tracebacks From Anywhere in a Program (symbolic):: -@end menu +@subsubheading Tracebacks From Exception Occurrences + + +Here is an example: -@node Tracebacks From Exception Occurrences (symbolic) -@subsubsection Tracebacks From Exception Occurrences +@quotation -@smallexample @c ada -@b{with} Ada.Text_IO; -@b{with} GNAT.Traceback.Symbolic; +@example +with Ada.Text_IO; +with GNAT.Traceback.Symbolic; -@b{procedure} STB @b{is} +procedure STB is - @b{procedure} P1 @b{is} - @b{begin} - @b{raise} Constraint_Error; - @b{end} P1; + procedure P1 is + begin + raise Constraint_Error; + end P1; - @b{procedure} P2 @b{is} - @b{begin} + procedure P2 is + begin P1; - @b{end} P2; + end P2; - @b{procedure} P3 @b{is} - @b{begin} + procedure P3 is + begin P2; - @b{end} P3; + end P3; -@b{begin} +begin P3; -@b{exception} - @b{when} E : @b{others} => +exception + when E : others => Ada.Text_IO.Put_Line (GNAT.Traceback.Symbolic.Symbolic_Traceback (E)); -@b{end} STB; -@end smallexample +end STB; +@end example -@smallexample +@example $ gnatmake -g .\stb -bargs -E $ stb @@ -21830,102 +26289,3015 @@ $ stb 004011C4 in __mingw_CRTStartup at crt1.c:200 004011F1 in mainCRTStartup at crt1.c:222 77E892A4 in ?? at ??:0 -@end smallexample +@end example +@end quotation -@noindent -In the above example the ``.\'' syntax in the @command{gnatmake} command -is currently required by @command{addr2line} for files that are in +In the above example the @code{.\} syntax in the @emph{gnatmake} command +is currently required by @emph{addr2line} for files that are in the current working directory. Moreover, the exact sequence of linker options may vary from platform to platform. -The above @option{-largs} section is for Windows platforms. By contrast, -under Unix there is no need for the @option{-largs} section. +The above @emph{-largs} section is for Windows platforms. By contrast, +under Unix there is no need for the @emph{-largs} section. Differences across platforms are due to details of linker implementation. -@node Tracebacks From Anywhere in a Program (symbolic) -@subsubsection Tracebacks From Anywhere in a Program +@subsubheading Tracebacks From Anywhere in a Program + -@noindent It is possible to get a symbolic stack traceback from anywhere in a program, just as for non-symbolic tracebacks. The first step is to obtain a non-symbolic -traceback, and then call @code{Symbolic_Traceback} to compute the symbolic +traceback, and then call @cite{Symbolic_Traceback} to compute the symbolic information. Here is an example: -@smallexample @c ada -@b{with} Ada.Text_IO; -@b{with} GNAT.Traceback; -@b{with} GNAT.Traceback.Symbolic; +@quotation + +@example +with Ada.Text_IO; +with GNAT.Traceback; +with GNAT.Traceback.Symbolic; -@b{procedure} STB @b{is} +procedure STB is - @b{use} Ada; - @b{use} GNAT.Traceback; - @b{use} GNAT.Traceback.Symbolic; + use Ada; + use GNAT.Traceback; + use GNAT.Traceback.Symbolic; - @b{procedure} P1 @b{is} + procedure P1 is TB : Tracebacks_Array (1 .. 10); - --@i{ We are asking for a maximum of 10 stack frames.} + -- We are asking for a maximum of 10 stack frames. Len : Natural; - --@i{ Len will receive the actual number of stack frames returned.} - @b{begin} + -- Len will receive the actual number of stack frames returned. + begin Call_Chain (TB, Len); Text_IO.Put_Line (Symbolic_Traceback (TB (1 .. Len))); - @b{end} P1; + end P1; - @b{procedure} P2 @b{is} - @b{begin} + procedure P2 is + begin P1; - @b{end} P2; + end P2; -@b{begin} +begin P2; -@b{end} STB; -@end smallexample +end STB; +@end example +@end quotation + +@geindex Code Coverage + +@geindex Profiling + +@node Code Coverage and Profiling,Improving Performance,Running and Debugging Ada Programs,GNAT and Program Execution +@anchor{gnat_ugn/gnat_and_program_execution id19}@anchor{1f1}@anchor{gnat_ugn/gnat_and_program_execution code-coverage-and-profiling}@anchor{27} +@section Code Coverage and Profiling + + +This section describes how to use the @cite{gcov} coverage testing tool and +the @cite{gprof} profiler tool on Ada programs. + +@geindex gcov + +@menu +* Code Coverage of Ada Programs with gcov:: +* Profiling an Ada Program with gprof:: + +@end menu + +@node Code Coverage of Ada Programs with gcov,Profiling an Ada Program with gprof,,Code Coverage and Profiling +@anchor{gnat_ugn/gnat_and_program_execution id20}@anchor{217}@anchor{gnat_ugn/gnat_and_program_execution code-coverage-of-ada-programs-with-gcov}@anchor{218} +@subsection Code Coverage of Ada Programs with gcov + + +@cite{gcov} is a test coverage program: it analyzes the execution of a given +program on selected tests, to help you determine the portions of the program +that are still untested. + +@cite{gcov} is part of the GCC suite, and is described in detail in the GCC +User's Guide. You can refer to this documentation for a more complete +description. + +This chapter provides a quick startup guide, and +details some GNAT-specific features. + +@menu +* Quick startup guide:: +* GNAT specifics:: + +@end menu + +@node Quick startup guide,GNAT specifics,,Code Coverage of Ada Programs with gcov +@anchor{gnat_ugn/gnat_and_program_execution id21}@anchor{219}@anchor{gnat_ugn/gnat_and_program_execution quick-startup-guide}@anchor{21a} +@subsubsection Quick startup guide + + +In order to perform coverage analysis of a program using @cite{gcov}, several +steps are needed: + + +@enumerate + +@item +Instrument the code during the compilation process, + +@item +Execute the instrumented program, and + +@item +Invoke the @cite{gcov} tool to generate the coverage results. +@end enumerate + +@geindex -fprofile-arcs (gcc) + +@geindex -ftest-coverage (gcc + +@geindex -fprofile-arcs (gnatbind) + +The code instrumentation needed by gcov is created at the object level. +The source code is not modified in any way, because the instrumentation code is +inserted by gcc during the compilation process. To compile your code with code +coverage activated, you need to recompile your whole project using the +switches +@cite{-fprofile-arcs} and @cite{-ftest-coverage}, and link it using +@cite{-fprofile-arcs}. + +@quotation + +@example +$ gnatmake -P my_project.gpr -f -cargs -fprofile-arcs -ftest-coverage \\ + -largs -fprofile-arcs +@end example +@end quotation + +This compilation process will create @code{.gcno} files together with +the usual object files. + +Once the program is compiled with coverage instrumentation, you can +run it as many times as needed -- on portions of a test suite for +example. The first execution will produce @code{.gcda} files at the +same location as the @code{.gcno} files. Subsequent executions +will update those files, so that a cumulative result of the covered +portions of the program is generated. + +Finally, you need to call the @cite{gcov} tool. The different options of +@cite{gcov} are described in the GCC User's Guide, section 'Invoking gcov'. + +This will create annotated source files with a @code{.gcov} extension: +@code{my_main.adb} file will be analyzed in @code{my_main.adb.gcov}. + +@node GNAT specifics,,Quick startup guide,Code Coverage of Ada Programs with gcov +@anchor{gnat_ugn/gnat_and_program_execution gnat-specifics}@anchor{21b}@anchor{gnat_ugn/gnat_and_program_execution id22}@anchor{21c} +@subsubsection GNAT specifics + + +Because of Ada semantics, portions of the source code may be shared among +several object files. This is the case for example when generics are +involved, when inlining is active or when declarations generate initialisation +calls. In order to take +into account this shared code, you need to call @cite{gcov} on all +source files of the tested program at once. + +The list of source files might exceed the system's maximum command line +length. In order to bypass this limitation, a new mechanism has been +implemented in @cite{gcov}: you can now list all your project's files into a +text file, and provide this file to gcov as a parameter, preceded by a @code{@@} +(e.g. @code{gcov @@mysrclist.txt}). + +Note that on AIX compiling a static library with @cite{-fprofile-arcs} is +not supported as there can be unresolved symbols during the final link. + +@geindex gprof + +@geindex Profiling + +@node Profiling an Ada Program with gprof,,Code Coverage of Ada Programs with gcov,Code Coverage and Profiling +@anchor{gnat_ugn/gnat_and_program_execution profiling-an-ada-program-with-gprof}@anchor{21d}@anchor{gnat_ugn/gnat_and_program_execution id23}@anchor{21e} +@subsection Profiling an Ada Program with gprof + + +This section is not meant to be an exhaustive documentation of @cite{gprof}. +Full documentation for it can be found in the @cite{GNU Profiler User's Guide} +documentation that is part of this GNAT distribution. + +Profiling a program helps determine the parts of a program that are executed +most often, and are therefore the most time-consuming. + +@cite{gprof} is the standard GNU profiling tool; it has been enhanced to +better handle Ada programs and multitasking. +It is currently supported on the following platforms + + +@itemize * + +@item +linux x86/x86_64 + +@item +solaris sparc/sparc64/x86 + +@item +windows x86 +@end itemize + +In order to profile a program using @cite{gprof}, several steps are needed: + + +@enumerate + +@item +Instrument the code, which requires a full recompilation of the project with the +proper switches. + +@item +Execute the program under the analysis conditions, i.e. with the desired +input. + +@item +Analyze the results using the @cite{gprof} tool. +@end enumerate + +The following sections detail the different steps, and indicate how +to interpret the results. + +@menu +* Compilation for profiling:: +* Program execution:: +* Running gprof:: +* Interpretation of profiling results:: + +@end menu + +@node Compilation for profiling,Program execution,,Profiling an Ada Program with gprof +@anchor{gnat_ugn/gnat_and_program_execution id24}@anchor{21f}@anchor{gnat_ugn/gnat_and_program_execution compilation-for-profiling}@anchor{220} +@subsubsection Compilation for profiling + + +@geindex -pg (gcc) +@geindex for profiling + +@geindex -pg (gnatlink) +@geindex for profiling + +In order to profile a program the first step is to tell the compiler +to generate the necessary profiling information. The compiler switch to be used +is @code{-pg}, which must be added to other compilation switches. This +switch needs to be specified both during compilation and link stages, and can +be specified once when using gnatmake: + +@quotation + +@example +$ gnatmake -f -pg -P my_project +@end example +@end quotation + +Note that only the objects that were compiled with the @code{-pg} switch will +be profiled; if you need to profile your whole project, use the @code{-f} +gnatmake switch to force full recompilation. + +@node Program execution,Running gprof,Compilation for profiling,Profiling an Ada Program with gprof +@anchor{gnat_ugn/gnat_and_program_execution program-execution}@anchor{221}@anchor{gnat_ugn/gnat_and_program_execution id25}@anchor{222} +@subsubsection Program execution + + +Once the program has been compiled for profiling, you can run it as usual. + +The only constraint imposed by profiling is that the program must terminate +normally. An interrupted program (via a Ctrl-C, kill, etc.) will not be +properly analyzed. + +Once the program completes execution, a data file called @code{gmon.out} is +generated in the directory where the program was launched from. If this file +already exists, it will be overwritten. + +@node Running gprof,Interpretation of profiling results,Program execution,Profiling an Ada Program with gprof +@anchor{gnat_ugn/gnat_and_program_execution running-gprof}@anchor{223}@anchor{gnat_ugn/gnat_and_program_execution id26}@anchor{224} +@subsubsection Running gprof + + +The @cite{gprof} tool is called as follow: + +@quotation + +@example +$ gprof my_prog gmon.out +@end example +@end quotation + +or simply: + +@quotation + +@example +$ gprof my_prog +@end example +@end quotation + +The complete form of the gprof command line is the following: + +@quotation + +@example +$ gprof [switches] [executable [data-file]] +@end example +@end quotation + +@cite{gprof} supports numerous switches. The order of these +switch does not matter. The full list of options can be found in +the GNU Profiler User's Guide documentation that comes with this documentation. + +The following is the subset of those switches that is most relevant: + +@geindex --demangle (gprof) + + +@table @asis + +@item @code{--demangle[=@emph{style}]}, @code{--no-demangle} + +These options control whether symbol names should be demangled when +printing output. The default is to demangle C++ symbols. The +@code{--no-demangle} option may be used to turn off demangling. Different +compilers have different mangling styles. The optional demangling style +argument can be used to choose an appropriate demangling style for your +compiler, in particular Ada symbols generated by GNAT can be demangled using +@code{--demangle=gnat}. +@end table + +@geindex -e (gprof) + + +@table @asis + +@item @code{-e @emph{function_name}} + +The @code{-e @emph{function}} option tells @cite{gprof} not to print +information about the function @cite{function_name} (and its +children...) in the call graph. The function will still be listed +as a child of any functions that call it, but its index number will be +shown as @code{[not printed]}. More than one @code{-e} option may be +given; only one @cite{function_name} may be indicated with each @code{-e} +option. +@end table + +@geindex -E (gprof) + + +@table @asis + +@item @code{-E @emph{function_name}} + +The @code{-E @emph{function}} option works like the @code{-e} option, but +execution time spent in the function (and children who were not called from +anywhere else), will not be used to compute the percentages-of-time for +the call graph. More than one @code{-E} option may be given; only one +@cite{function_name} may be indicated with each @code{-E} option. +@end table + +@geindex -f (gprof) + + +@table @asis + +@item @code{-f @emph{function_name}} + +The @code{-f @emph{function}} option causes @cite{gprof} to limit the +call graph to the function @cite{function_name} and its children (and +their children...). More than one @code{-f} option may be given; +only one @cite{function_name} may be indicated with each @code{-f} +option. +@end table + +@geindex -F (gprof) + + +@table @asis + +@item @code{-F @emph{function_name}} + +The @code{-F @emph{function}} option works like the @code{-f} option, but +only time spent in the function and its children (and their +children...) will be used to determine total-time and +percentages-of-time for the call graph. More than one @code{-F} option +may be given; only one @cite{function_name} may be indicated with each +@code{-F} option. The @code{-F} option overrides the @code{-E} option. +@end table + +@node Interpretation of profiling results,,Running gprof,Profiling an Ada Program with gprof +@anchor{gnat_ugn/gnat_and_program_execution id27}@anchor{225}@anchor{gnat_ugn/gnat_and_program_execution interpretation-of-profiling-results}@anchor{226} +@subsubsection Interpretation of profiling results + + +The results of the profiling analysis are represented by two arrays: the +'flat profile' and the 'call graph'. Full documentation of those outputs +can be found in the GNU Profiler User's Guide. + +The flat profile shows the time spent in each function of the program, and how +many time it has been called. This allows you to locate easily the most +time-consuming functions. + +The call graph shows, for each subprogram, the subprograms that call it, +and the subprograms that it calls. It also provides an estimate of the time +spent in each of those callers/called subprograms. + +@node Improving Performance,Overflow Check Handling in GNAT,Code Coverage and Profiling,GNAT and Program Execution +@anchor{gnat_ugn/gnat_and_program_execution improving-performance}@anchor{28}@anchor{gnat_ugn/gnat_and_program_execution id28}@anchor{1f2} +@section Improving Performance + + +@geindex Improving performance + +This section presents several topics related to program performance. +It first describes some of the tradeoffs that need to be considered +and some of the techniques for making your program run faster. + + +It then documents the unused subprogram/data elimination feature, +which can reduce the size of program executables. + +@menu +* Performance Considerations:: +* Text_IO Suggestions:: +* Reducing Size of Executables with Unused Subprogram/Data Elimination:: + +@end menu + +@node Performance Considerations,Text_IO Suggestions,,Improving Performance +@anchor{gnat_ugn/gnat_and_program_execution id29}@anchor{227}@anchor{gnat_ugn/gnat_and_program_execution performance-considerations}@anchor{228} +@subsection Performance Considerations + + +The GNAT system provides a number of options that allow a trade-off +between + + +@itemize * + +@item +performance of the generated code + +@item +speed of compilation + +@item +minimization of dependences and recompilation + +@item +the degree of run-time checking. +@end itemize + +The defaults (if no options are selected) aim at improving the speed +of compilation and minimizing dependences, at the expense of performance +of the generated code: + + +@itemize * + +@item +no optimization + +@item +no inlining of subprogram calls + +@item +all run-time checks enabled except overflow and elaboration checks +@end itemize + +These options are suitable for most program development purposes. This +section describes how you can modify these choices, and also provides +some guidelines on debugging optimized code. + +@menu +* Controlling Run-Time Checks:: +* Use of Restrictions:: +* Optimization Levels:: +* Debugging Optimized Code:: +* Inlining of Subprograms:: +* Floating_Point_Operations:: +* Vectorization of loops:: +* Other Optimization Switches:: +* Optimization and Strict Aliasing:: +* Aliased Variables and Optimization:: +* Atomic Variables and Optimization:: +* Passive Task Optimization:: + +@end menu + +@node Controlling Run-Time Checks,Use of Restrictions,,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution controlling-run-time-checks}@anchor{229}@anchor{gnat_ugn/gnat_and_program_execution id30}@anchor{22a} +@subsubsection Controlling Run-Time Checks + + +By default, GNAT generates all run-time checks, except integer overflow +checks, stack overflow checks, and checks for access before elaboration on +subprogram calls. The latter are not required in default mode, because all +necessary checking is done at compile time. + +@geindex -gnatp (gcc) + +@geindex -gnato (gcc) + +Two gnat switches, @emph{-gnatp} and @emph{-gnato} allow this default to +be modified. See @ref{fe,,Run-Time Checks}. + +Our experience is that the default is suitable for most development +purposes. + +We treat integer overflow specially because these +are quite expensive and in our experience are not as important as other +run-time checks in the development process. Note that division by zero +is not considered an overflow check, and divide by zero checks are +generated where required by default. + +Elaboration checks are off by default, and also not needed by default, since +GNAT uses a static elaboration analysis approach that avoids the need for +run-time checking. This manual contains a full chapter discussing the issue +of elaboration checks, and if the default is not satisfactory for your use, +you should read this chapter. + +For validity checks, the minimal checks required by the Ada Reference +Manual (for case statements and assignments to array elements) are on +by default. These can be suppressed by use of the @emph{-gnatVn} switch. +Note that in Ada 83, there were no validity checks, so if the Ada 83 mode +is acceptable (or when comparing GNAT performance with an Ada 83 compiler), +it may be reasonable to routinely use @emph{-gnatVn}. Validity checks +are also suppressed entirely if @emph{-gnatp} is used. + +@geindex Overflow checks + +@geindex Checks +@geindex overflow + +@geindex Suppress + +@geindex Unsuppress + +@geindex pragma Suppress + +@geindex pragma Unsuppress + +Note that the setting of the switches controls the default setting of +the checks. They may be modified using either @cite{pragma Suppress} (to +remove checks) or @cite{pragma Unsuppress} (to add back suppressed +checks) in the program source. + +@node Use of Restrictions,Optimization Levels,Controlling Run-Time Checks,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution use-of-restrictions}@anchor{22b}@anchor{gnat_ugn/gnat_and_program_execution id31}@anchor{22c} +@subsubsection Use of Restrictions + + +The use of pragma Restrictions allows you to control which features are +permitted in your program. Apart from the obvious point that if you avoid +relatively expensive features like finalization (enforceable by the use +of pragma Restrictions (No_Finalization), the use of this pragma does not +affect the generated code in most cases. + +One notable exception to this rule is that the possibility of task abort +results in some distributed overhead, particularly if finalization or +exception handlers are used. The reason is that certain sections of code +have to be marked as non-abortable. + +If you use neither the @cite{abort} statement, nor asynchronous transfer +of control (@cite{select ... then abort}), then this distributed overhead +is removed, which may have a general positive effect in improving +overall performance. Especially code involving frequent use of tasking +constructs and controlled types will show much improved performance. +The relevant restrictions pragmas are + +@quotation + +@example +pragma Restrictions (No_Abort_Statements); +pragma Restrictions (Max_Asynchronous_Select_Nesting => 0); +@end example +@end quotation + +It is recommended that these restriction pragmas be used if possible. Note +that this also means that you can write code without worrying about the +possibility of an immediate abort at any point. + +@node Optimization Levels,Debugging Optimized Code,Use of Restrictions,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution id32}@anchor{22d}@anchor{gnat_ugn/gnat_and_program_execution optimization-levels}@anchor{101} +@subsubsection Optimization Levels + + +@geindex -O (gcc) + +Without any optimization option, +the compiler's goal is to reduce the cost of +compilation and to make debugging produce the expected results. +Statements are independent: if you stop the program with a breakpoint between +statements, you can then assign a new value to any variable or change +the program counter to any other statement in the subprogram and get exactly +the results you would expect from the source code. + +Turning on optimization makes the compiler attempt to improve the +performance and/or code size at the expense of compilation time and +possibly the ability to debug the program. + +If you use multiple +-O options, with or without level numbers, +the last such option is the one that is effective. + +The default is optimization off. This results in the fastest compile +times, but GNAT makes absolutely no attempt to optimize, and the +generated programs are considerably larger and slower than when +optimization is enabled. You can use the +@emph{-O} switch (the permitted forms are @emph{-O0}, @emph{-O1} +@emph{-O2}, @emph{-O3}, and @emph{-Os}) +to @emph{gcc} to control the optimization level: + + +@itemize * + +@item + +@table @asis + +@item @emph{-O0} + +No optimization (the default); +generates unoptimized code but has +the fastest compilation time. + +Note that many other compilers do fairly extensive optimization +even if 'no optimization' is specified. With gcc, it is +very unusual to use -O0 for production if +execution time is of any concern, since -O0 +really does mean no optimization at all. This difference between +gcc and other compilers should be kept in mind when doing +performance comparisons. +@end table + +@item + +@table @asis + +@item @emph{-O1} + +Moderate optimization; +optimizes reasonably well but does not +degrade compilation time significantly. +@end table + +@item + +@table @asis + +@item @emph{-O2} + +Full optimization; +generates highly optimized code and has +the slowest compilation time. +@end table + +@item + +@table @asis + +@item @emph{-O3} + +Full optimization as in @emph{-O2}; +also uses more aggressive automatic inlining of subprograms within a unit +(@ref{114,,Inlining of Subprograms}) and attempts to vectorize loops. +@end table + +@item + +@table @asis + +@item @emph{-Os} + +Optimize space usage (code and data) of resulting program. +@end table +@end itemize + +Higher optimization levels perform more global transformations on the +program and apply more expensive analysis algorithms in order to generate +faster and more compact code. The price in compilation time, and the +resulting improvement in execution time, +both depend on the particular application and the hardware environment. +You should experiment to find the best level for your application. + +Since the precise set of optimizations done at each level will vary from +release to release (and sometime from target to target), it is best to think +of the optimization settings in general terms. +See the @emph{Options That Control Optimization} section in +@cite{Using the GNU Compiler Collection (GCC)} +for details about +the @emph{-O} settings and a number of @emph{-f} options that +individually enable or disable specific optimizations. + +Unlike some other compilation systems, @emph{gcc} has +been tested extensively at all optimization levels. There are some bugs +which appear only with optimization turned on, but there have also been +bugs which show up only in @emph{unoptimized} code. Selecting a lower +level of optimization does not improve the reliability of the code +generator, which in practice is highly reliable at all optimization +levels. + +Note regarding the use of @emph{-O3}: The use of this optimization level +is generally discouraged with GNAT, since it often results in larger +executables which may run more slowly. See further discussion of this point +in @ref{114,,Inlining of Subprograms}. + +@node Debugging Optimized Code,Inlining of Subprograms,Optimization Levels,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution id33}@anchor{22e}@anchor{gnat_ugn/gnat_and_program_execution debugging-optimized-code}@anchor{22f} +@subsubsection Debugging Optimized Code + + +@geindex Debugging optimized code + +@geindex Optimization and debugging + +Although it is possible to do a reasonable amount of debugging at +nonzero optimization levels, +the higher the level the more likely that +source-level constructs will have been eliminated by optimization. +For example, if a loop is strength-reduced, the loop +control variable may be completely eliminated and thus cannot be +displayed in the debugger. +This can only happen at @emph{-O2} or @emph{-O3}. +Explicit temporary variables that you code might be eliminated at +level @emph{-O1} or higher. + +@geindex -g (gcc) + +The use of the @emph{-g} switch, +which is needed for source-level debugging, +affects the size of the program executable on disk, +and indeed the debugging information can be quite large. +However, it has no effect on the generated code (and thus does not +degrade performance) + +Since the compiler generates debugging tables for a compilation unit before +it performs optimizations, the optimizing transformations may invalidate some +of the debugging data. You therefore need to anticipate certain +anomalous situations that may arise while debugging optimized code. +These are the most common cases: + + +@itemize * + +@item +@emph{The 'hopping Program Counter':} Repeated @cite{step} or @cite{next} +commands show +the PC bouncing back and forth in the code. This may result from any of +the following optimizations: + + +@itemize - + +@item +@emph{Common subexpression elimination:} using a single instance of code for a +quantity that the source computes several times. As a result you +may not be able to stop on what looks like a statement. + +@item +@emph{Invariant code motion:} moving an expression that does not change within a +loop, to the beginning of the loop. + +@item +@emph{Instruction scheduling:} moving instructions so as to +overlap loads and stores (typically) with other code, or in +general to move computations of values closer to their uses. Often +this causes you to pass an assignment statement without the assignment +happening and then later bounce back to the statement when the +value is actually needed. Placing a breakpoint on a line of code +and then stepping over it may, therefore, not always cause all the +expected side-effects. +@end itemize + +@item +@emph{The 'big leap':} More commonly known as @emph{cross-jumping}, in which +two identical pieces of code are merged and the program counter suddenly +jumps to a statement that is not supposed to be executed, simply because +it (and the code following) translates to the same thing as the code +that @emph{was} supposed to be executed. This effect is typically seen in +sequences that end in a jump, such as a @cite{goto}, a @cite{return}, or +a @cite{break} in a C @cite{switch} statement. + +@item +@emph{The 'roving variable':} The symptom is an unexpected value in a variable. +There are various reasons for this effect: + + +@itemize - + +@item +In a subprogram prologue, a parameter may not yet have been moved to its +'home'. + +@item +A variable may be dead, and its register re-used. This is +probably the most common cause. + +@item +As mentioned above, the assignment of a value to a variable may +have been moved. + +@item +A variable may be eliminated entirely by value propagation or +other means. In this case, GCC may incorrectly generate debugging +information for the variable +@end itemize + +In general, when an unexpected value appears for a local variable or parameter +you should first ascertain if that value was actually computed by +your program, as opposed to being incorrectly reported by the debugger. +Record fields or +array elements in an object designated by an access value +are generally less of a problem, once you have ascertained that the access +value is sensible. +Typically, this means checking variables in the preceding code and in the +calling subprogram to verify that the value observed is explainable from other +values (one must apply the procedure recursively to those +other values); or re-running the code and stopping a little earlier +(perhaps before the call) and stepping to better see how the variable obtained +the value in question; or continuing to step @emph{from} the point of the +strange value to see if code motion had simply moved the variable's +assignments later. +@end itemize + +In light of such anomalies, a recommended technique is to use @emph{-O0} +early in the software development cycle, when extensive debugging capabilities +are most needed, and then move to @emph{-O1} and later @emph{-O2} as +the debugger becomes less critical. +Whether to use the @emph{-g} switch in the release version is +a release management issue. +Note that if you use @emph{-g} you can then use the @emph{strip} program +on the resulting executable, +which removes both debugging information and global symbols. + +@node Inlining of Subprograms,Floating_Point_Operations,Debugging Optimized Code,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution id34}@anchor{230}@anchor{gnat_ugn/gnat_and_program_execution inlining-of-subprograms}@anchor{114} +@subsubsection Inlining of Subprograms + + +A call to a subprogram in the current unit is inlined if all the +following conditions are met: + + +@itemize * + +@item +The optimization level is at least @emph{-O1}. + +@item +The called subprogram is suitable for inlining: It must be small enough +and not contain something that @emph{gcc} cannot support in inlined +subprograms. + +@geindex pragma Inline + +@geindex Inline + +@item +Any one of the following applies: @cite{pragma Inline} is applied to the +subprogram and the @emph{-gnatn} switch is specified; the +subprogram is local to the unit and called once from within it; the +subprogram is small and optimization level @emph{-O2} is specified; +optimization level @emph{-O3} is specified. +@end itemize + +Calls to subprograms in @emph{with}ed units are normally not inlined. +To achieve actual inlining (that is, replacement of the call by the code +in the body of the subprogram), the following conditions must all be true: + + +@itemize * + +@item +The optimization level is at least @emph{-O1}. + +@item +The called subprogram is suitable for inlining: It must be small enough +and not contain something that @emph{gcc} cannot support in inlined +subprograms. + +@item +The call appears in a body (not in a package spec). + +@item +There is a @cite{pragma Inline} for the subprogram. + +@item +The @emph{-gnatn} switch is used on the command line. +@end itemize + +Even if all these conditions are met, it may not be possible for +the compiler to inline the call, due to the length of the body, +or features in the body that make it impossible for the compiler +to do the inlining. + +Note that specifying the @emph{-gnatn} switch causes additional +compilation dependencies. Consider the following: + +@quotation + +@example +package R is + procedure Q; + pragma Inline (Q); +end R; +package body R is + ... +end R; + +with R; +procedure Main is +begin + ... + R.Q; +end Main; +@end example +@end quotation + +With the default behavior (no @emph{-gnatn} switch specified), the +compilation of the @cite{Main} procedure depends only on its own source, +@code{main.adb}, and the spec of the package in file @code{r.ads}. This +means that editing the body of @cite{R} does not require recompiling +@cite{Main}. + +On the other hand, the call @cite{R.Q} is not inlined under these +circumstances. If the @emph{-gnatn} switch is present when @cite{Main} +is compiled, the call will be inlined if the body of @cite{Q} is small +enough, but now @cite{Main} depends on the body of @cite{R} in +@code{r.adb} as well as on the spec. This means that if this body is edited, +the main program must be recompiled. Note that this extra dependency +occurs whether or not the call is in fact inlined by @emph{gcc}. + +The use of front end inlining with @emph{-gnatN} generates similar +additional dependencies. + +@geindex -fno-inline (gcc) + +Note: The @emph{-fno-inline} switch overrides all other conditions and ensures that +no inlining occurs, unless requested with pragma Inline_Always for gcc +back-ends. The extra dependences resulting from @emph{-gnatn} will still be active, +even if this switch is used to suppress the resulting inlining actions. + +@geindex -fno-inline-functions (gcc) + +Note: The @emph{-fno-inline-functions} switch can be used to prevent +automatic inlining of subprograms if @emph{-O3} is used. + +@geindex -fno-inline-small-functions (gcc) + +Note: The @emph{-fno-inline-small-functions} switch can be used to prevent +automatic inlining of small subprograms if @emph{-O2} is used. + +@geindex -fno-inline-functions-called-once (gcc) + +Note: The @emph{-fno-inline-functions-called-once} switch +can be used to prevent inlining of subprograms local to the unit +and called once from within it if @emph{-O1} is used. + +Note regarding the use of @emph{-O3}: @emph{-gnatn} is made up of two +sub-switches @emph{-gnatn1} and @emph{-gnatn2} that can be directly +specified in lieu of it, @emph{-gnatn} being translated into one of them +based on the optimization level. With @emph{-O2} or below, @emph{-gnatn} +is equivalent to @emph{-gnatn1} which activates pragma @cite{Inline} with +moderate inlining across modules. With @emph{-O3}, @emph{-gnatn} is +equivalent to @emph{-gnatn2} which activates pragma @cite{Inline} with +full inlining across modules. If you have used pragma @cite{Inline} in +appropriate cases, then it is usually much better to use @emph{-O2} +and @emph{-gnatn} and avoid the use of @emph{-O3} which has the additional +effect of inlining subprograms you did not think should be inlined. We have +found that the use of @emph{-O3} may slow down the compilation and increase +the code size by performing excessive inlining, leading to increased +instruction cache pressure from the increased code size and thus minor +performance improvements. So the bottom line here is that you should not +automatically assume that @emph{-O3} is better than @emph{-O2}, and +indeed you should use @emph{-O3} only if tests show that it actually +improves performance for your program. + +@node Floating_Point_Operations,Vectorization of loops,Inlining of Subprograms,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution floating-point-operations}@anchor{231}@anchor{gnat_ugn/gnat_and_program_execution id35}@anchor{232} +@subsubsection Floating_Point_Operations + + +@geindex Floating-Point Operations + +On almost all targets, GNAT maps Float and Long_Float to the 32-bit and +64-bit standard IEEE floating-point representations, and operations will +use standard IEEE arithmetic as provided by the processor. On most, but +not all, architectures, the attribute Machine_Overflows is False for these +types, meaning that the semantics of overflow is implementation-defined. +In the case of GNAT, these semantics correspond to the normal IEEE +treatment of infinities and NaN (not a number) values. For example, +1.0 / 0.0 yields plus infinitiy and 0.0 / 0.0 yields a NaN. By +avoiding explicit overflow checks, the performance is greatly improved +on many targets. However, if required, floating-point overflow can be +enabled by the use of the pragma Check_Float_Overflow. + +Another consideration that applies specifically to x86 32-bit +architectures is which form of floating-point arithmetic is used. +By default the operations use the old style x86 floating-point, +which implements an 80-bit extended precision form (on these +architectures the type Long_Long_Float corresponds to that form). +In addition, generation of efficient code in this mode means that +the extended precision form will be used for intermediate results. +This may be helpful in improving the final precision of a complex +expression. However it means that the results obtained on the x86 +will be different from those on other architectures, and for some +algorithms, the extra intermediate precision can be detrimental. + +In addition to this old-style floating-point, all modern x86 chips +implement an alternative floating-point operation model referred +to as SSE2. In this model there is no extended form, and furthermore +execution performance is significantly enhanced. To force GNAT to use +this more modern form, use both of the switches: + +@quotation + +-msse2 -mfpmath=sse +@end quotation + +A unit compiled with these switches will automatically use the more +efficient SSE2 instruction set for Float and Long_Float operations. +Note that the ABI has the same form for both floating-point models, +so it is permissible to mix units compiled with and without these +switches. + +@node Vectorization of loops,Other Optimization Switches,Floating_Point_Operations,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution id36}@anchor{233}@anchor{gnat_ugn/gnat_and_program_execution vectorization-of-loops}@anchor{234} +@subsubsection Vectorization of loops + + +@geindex Optimization Switches + +You can take advantage of the auto-vectorizer present in the @emph{gcc} +back end to vectorize loops with GNAT. The corresponding command line switch +is @emph{-ftree-vectorize} but, as it is enabled by default at @emph{-O3} +and other aggressive optimizations helpful for vectorization also are enabled +by default at this level, using @emph{-O3} directly is recommended. + +You also need to make sure that the target architecture features a supported +SIMD instruction set. For example, for the x86 architecture, you should at +least specify @emph{-msse2} to get significant vectorization (but you don't +need to specify it for x86-64 as it is part of the base 64-bit architecture). +Similarly, for the PowerPC architecture, you should specify @emph{-maltivec}. + +The preferred loop form for vectorization is the @cite{for} iteration scheme. +Loops with a @cite{while} iteration scheme can also be vectorized if they are +very simple, but the vectorizer will quickly give up otherwise. With either +iteration scheme, the flow of control must be straight, in particular no +@cite{exit} statement may appear in the loop body. The loop may however +contain a single nested loop, if it can be vectorized when considered alone: + +@quotation + +@example +A : array (1..4, 1..4) of Long_Float; +S : array (1..4) of Long_Float; + +procedure Sum is +begin + for I in A'Range(1) loop + for J in A'Range(2) loop + S (I) := S (I) + A (I, J); + end loop; + end loop; +end Sum; +@end example +@end quotation + +The vectorizable operations depend on the targeted SIMD instruction set, but +the adding and some of the multiplying operators are generally supported, as +well as the logical operators for modular types. Note that, in the former +case, enabling overflow checks, for example with @emph{-gnato}, totally +disables vectorization. The other checks are not supposed to have the same +definitive effect, although compiling with @emph{-gnatp} might well reveal +cases where some checks do thwart vectorization. + +Type conversions may also prevent vectorization if they involve semantics that +are not directly supported by the code generator or the SIMD instruction set. +A typical example is direct conversion from floating-point to integer types. +The solution in this case is to use the following idiom: + +@quotation + +@example +Integer (S'Truncation (F)) +@end example +@end quotation + +if @cite{S} is the subtype of floating-point object @cite{F}. + +In most cases, the vectorizable loops are loops that iterate over arrays. +All kinds of array types are supported, i.e. constrained array types with +static bounds: + +@quotation + +@example +type Array_Type is array (1 .. 4) of Long_Float; +@end example +@end quotation + +constrained array types with dynamic bounds: + +@quotation + +@example +type Array_Type is array (1 .. Q.N) of Long_Float; + +type Array_Type is array (Q.K .. 4) of Long_Float; + +type Array_Type is array (Q.K .. Q.N) of Long_Float; +@end example +@end quotation + +or unconstrained array types: + +@quotation + +@example +type Array_Type is array (Positive range <>) of Long_Float; +@end example +@end quotation + +The quality of the generated code decreases when the dynamic aspect of the +array type increases, the worst code being generated for unconstrained array +types. This is so because, the less information the compiler has about the +bounds of the array, the more fallback code it needs to generate in order to +fix things up at run time. + +It is possible to specify that a given loop should be subject to vectorization +preferably to other optimizations by means of pragma @cite{Loop_Optimize}: + +@quotation + +@example +pragma Loop_Optimize (Vector); +@end example +@end quotation + +placed immediately within the loop will convey the appropriate hint to the +compiler for this loop. + +It is also possible to help the compiler generate better vectorized code +for a given loop by asserting that there are no loop-carried dependencies +in the loop. Consider for example the procedure: + +@quotation + +@example +type Arr is array (1 .. 4) of Long_Float; + +procedure Add (X, Y : not null access Arr; R : not null access Arr) is +begin + for I in Arr'Range loop + R(I) := X(I) + Y(I); + end loop; +end; +@end example +@end quotation + +By default, the compiler cannot unconditionally vectorize the loop because +assigning to a component of the array designated by R in one iteration could +change the value read from the components of the array designated by X or Y +in a later iteration. As a result, the compiler will generate two versions +of the loop in the object code, one vectorized and the other not vectorized, +as well as a test to select the appropriate version at run time. This can +be overcome by another hint: + +@quotation + +@example +pragma Loop_Optimize (Ivdep); +@end example +@end quotation + +placed immediately within the loop will tell the compiler that it can safely +omit the non-vectorized version of the loop as well as the run-time test. + +@node Other Optimization Switches,Optimization and Strict Aliasing,Vectorization of loops,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution id37}@anchor{235}@anchor{gnat_ugn/gnat_and_program_execution other-optimization-switches}@anchor{236} +@subsubsection Other Optimization Switches + + +@geindex Optimization Switches + +Since @cite{GNAT} uses the @emph{gcc} back end, all the specialized +@emph{gcc} optimization switches are potentially usable. These switches +have not been extensively tested with GNAT but can generally be expected +to work. Examples of switches in this category are @emph{-funroll-loops} +and the various target-specific @emph{-m} options (in particular, it has +been observed that @emph{-march=xxx} can significantly improve performance +on appropriate machines). For full details of these switches, see +the @cite{Submodel Options} section in the @cite{Hardware Models and Configurations} +chapter of @cite{Using the GNU Compiler Collection (GCC)}. + +@node Optimization and Strict Aliasing,Aliased Variables and Optimization,Other Optimization Switches,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution optimization-and-strict-aliasing}@anchor{f8}@anchor{gnat_ugn/gnat_and_program_execution id38}@anchor{237} +@subsubsection Optimization and Strict Aliasing + + +@geindex Aliasing + +@geindex Strict Aliasing + +@geindex No_Strict_Aliasing + +The strong typing capabilities of Ada allow an optimizer to generate +efficient code in situations where other languages would be forced to +make worst case assumptions preventing such optimizations. Consider +the following example: + +@quotation + +@example +procedure R is + type Int1 is new Integer; + type Int2 is new Integer; + type Int1A is access Int1; + type Int2A is access Int2; + Int1V : Int1A; + Int2V : Int2A; + ... + +begin + ... + for J in Data'Range loop + if Data (J) = Int1V.all then + Int2V.all := Int2V.all + 1; + end if; + end loop; + ... +end R; +@end example +@end quotation + +In this example, since the variable @cite{Int1V} can only access objects +of type @cite{Int1}, and @cite{Int2V} can only access objects of type +@cite{Int2}, there is no possibility that the assignment to +@cite{Int2V.all} affects the value of @cite{Int1V.all}. This means that +the compiler optimizer can "know" that the value @cite{Int1V.all} is constant +for all iterations of the loop and avoid the extra memory reference +required to dereference it each time through the loop. + +This kind of optimization, called strict aliasing analysis, is +triggered by specifying an optimization level of @emph{-O2} or +higher or @emph{-Os} and allows @cite{GNAT} to generate more efficient code +when access values are involved. + +However, although this optimization is always correct in terms of +the formal semantics of the Ada Reference Manual, difficulties can +arise if features like @cite{Unchecked_Conversion} are used to break +the typing system. Consider the following complete program example: + +@quotation + +@example +package p1 is + type int1 is new integer; + type int2 is new integer; + type a1 is access int1; + type a2 is access int2; +end p1; + +with p1; use p1; +package p2 is + function to_a2 (Input : a1) return a2; +end p2; + +with Unchecked_Conversion; +package body p2 is + function to_a2 (Input : a1) return a2 is + function to_a2u is + new Unchecked_Conversion (a1, a2); + begin + return to_a2u (Input); + end to_a2; +end p2; + +with p2; use p2; +with p1; use p1; +with Text_IO; use Text_IO; +procedure m is + v1 : a1 := new int1; + v2 : a2 := to_a2 (v1); +begin + v1.all := 1; + v2.all := 0; + put_line (int1'image (v1.all)); +end; +@end example +@end quotation + +This program prints out 0 in @emph{-O0} or @emph{-O1} +mode, but it prints out 1 in @emph{-O2} mode. That's +because in strict aliasing mode, the compiler can and +does assume that the assignment to @cite{v2.all} could not +affect the value of @cite{v1.all}, since different types +are involved. + +This behavior is not a case of non-conformance with the standard, since +the Ada RM specifies that an unchecked conversion where the resulting +bit pattern is not a correct value of the target type can result in an +abnormal value and attempting to reference an abnormal value makes the +execution of a program erroneous. That's the case here since the result +does not point to an object of type @cite{int2}. This means that the +effect is entirely unpredictable. + +However, although that explanation may satisfy a language +lawyer, in practice an applications programmer expects an +unchecked conversion involving pointers to create true +aliases and the behavior of printing 1 seems plain wrong. +In this case, the strict aliasing optimization is unwelcome. + +Indeed the compiler recognizes this possibility, and the +unchecked conversion generates a warning: + +@quotation + +@example +p2.adb:5:07: warning: possible aliasing problem with type "a2" +p2.adb:5:07: warning: use -fno-strict-aliasing switch for references +p2.adb:5:07: warning: or use "pragma No_Strict_Aliasing (a2);" +@end example +@end quotation + +Unfortunately the problem is recognized when compiling the body of +package @cite{p2}, but the actual "bad" code is generated while +compiling the body of @cite{m} and this latter compilation does not see +the suspicious @cite{Unchecked_Conversion}. + +As implied by the warning message, there are approaches you can use to +avoid the unwanted strict aliasing optimization in a case like this. + +One possibility is to simply avoid the use of @emph{-O2}, but +that is a bit drastic, since it throws away a number of useful +optimizations that do not involve strict aliasing assumptions. + +A less drastic approach is to compile the program using the +option @emph{-fno-strict-aliasing}. Actually it is only the +unit containing the dereferencing of the suspicious pointer +that needs to be compiled. So in this case, if we compile +unit @cite{m} with this switch, then we get the expected +value of zero printed. Analyzing which units might need +the switch can be painful, so a more reasonable approach +is to compile the entire program with options @emph{-O2} +and @emph{-fno-strict-aliasing}. If the performance is +satisfactory with this combination of options, then the +advantage is that the entire issue of possible "wrong" +optimization due to strict aliasing is avoided. + +To avoid the use of compiler switches, the configuration +pragma @cite{No_Strict_Aliasing} with no parameters may be +used to specify that for all access types, the strict +aliasing optimization should be suppressed. + +However, these approaches are still overkill, in that they causes +all manipulations of all access values to be deoptimized. A more +refined approach is to concentrate attention on the specific +access type identified as problematic. + +First, if a careful analysis of uses of the pointer shows +that there are no possible problematic references, then +the warning can be suppressed by bracketing the +instantiation of @cite{Unchecked_Conversion} to turn +the warning off: + +@quotation + +@example +pragma Warnings (Off); +function to_a2u is + new Unchecked_Conversion (a1, a2); +pragma Warnings (On); +@end example +@end quotation + +Of course that approach is not appropriate for this particular +example, since indeed there is a problematic reference. In this +case we can take one of two other approaches. + +The first possibility is to move the instantiation of unchecked +conversion to the unit in which the type is declared. In +this example, we would move the instantiation of +@cite{Unchecked_Conversion} from the body of package +@cite{p2} to the spec of package @cite{p1}. Now the +warning disappears. That's because any use of the +access type knows there is a suspicious unchecked +conversion, and the strict aliasing optimization +is automatically suppressed for the type. + +If it is not practical to move the unchecked conversion to the same unit +in which the destination access type is declared (perhaps because the +source type is not visible in that unit), you may use pragma +@cite{No_Strict_Aliasing} for the type. This pragma must occur in the +same declarative sequence as the declaration of the access type: + +@quotation + +@example +type a2 is access int2; +pragma No_Strict_Aliasing (a2); +@end example +@end quotation + +Here again, the compiler now knows that the strict aliasing optimization +should be suppressed for any reference to type @cite{a2} and the +expected behavior is obtained. + +Finally, note that although the compiler can generate warnings for +simple cases of unchecked conversions, there are tricker and more +indirect ways of creating type incorrect aliases which the compiler +cannot detect. Examples are the use of address overlays and unchecked +conversions involving composite types containing access types as +components. In such cases, no warnings are generated, but there can +still be aliasing problems. One safe coding practice is to forbid the +use of address clauses for type overlaying, and to allow unchecked +conversion only for primitive types. This is not really a significant +restriction since any possible desired effect can be achieved by +unchecked conversion of access values. + +The aliasing analysis done in strict aliasing mode can certainly +have significant benefits. We have seen cases of large scale +application code where the time is increased by up to 5% by turning +this optimization off. If you have code that includes significant +usage of unchecked conversion, you might want to just stick with +@emph{-O1} and avoid the entire issue. If you get adequate +performance at this level of optimization level, that's probably +the safest approach. If tests show that you really need higher +levels of optimization, then you can experiment with @emph{-O2} +and @emph{-O2 -fno-strict-aliasing} to see how much effect this +has on size and speed of the code. If you really need to use +@emph{-O2} with strict aliasing in effect, then you should +review any uses of unchecked conversion of access types, +particularly if you are getting the warnings described above. + +@node Aliased Variables and Optimization,Atomic Variables and Optimization,Optimization and Strict Aliasing,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution aliased-variables-and-optimization}@anchor{238}@anchor{gnat_ugn/gnat_and_program_execution id39}@anchor{239} +@subsubsection Aliased Variables and Optimization + + +@geindex Aliasing + +There are scenarios in which programs may +use low level techniques to modify variables +that otherwise might be considered to be unassigned. For example, +a variable can be passed to a procedure by reference, which takes +the address of the parameter and uses the address to modify the +variable's value, even though it is passed as an IN parameter. +Consider the following example: + +@quotation + +@example +procedure P is + Max_Length : constant Natural := 16; + type Char_Ptr is access all Character; + + procedure Get_String(Buffer: Char_Ptr; Size : Integer); + pragma Import (C, Get_String, "get_string"); + + Name : aliased String (1 .. Max_Length) := (others => ' '); + Temp : Char_Ptr; + + function Addr (S : String) return Char_Ptr is + function To_Char_Ptr is + new Ada.Unchecked_Conversion (System.Address, Char_Ptr); + begin + return To_Char_Ptr (S (S'First)'Address); + end; + +begin + Temp := Addr (Name); + Get_String (Temp, Max_Length); +end; +@end example +@end quotation + +where Get_String is a C function that uses the address in Temp to +modify the variable @cite{Name}. This code is dubious, and arguably +erroneous, and the compiler would be entitled to assume that +@cite{Name} is never modified, and generate code accordingly. + +However, in practice, this would cause some existing code that +seems to work with no optimization to start failing at high +levels of optimzization. + +What the compiler does for such cases is to assume that marking +a variable as aliased indicates that some "funny business" may +be going on. The optimizer recognizes the aliased keyword and +inhibits optimizations that assume the value cannot be assigned. +This means that the above example will in fact "work" reliably, +that is, it will produce the expected results. + +@node Atomic Variables and Optimization,Passive Task Optimization,Aliased Variables and Optimization,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution atomic-variables-and-optimization}@anchor{23a}@anchor{gnat_ugn/gnat_and_program_execution id40}@anchor{23b} +@subsubsection Atomic Variables and Optimization + + +@geindex Atomic + +There are two considerations with regard to performance when +atomic variables are used. + +First, the RM only guarantees that access to atomic variables +be atomic, it has nothing to say about how this is achieved, +though there is a strong implication that this should not be +achieved by explicit locking code. Indeed GNAT will never +generate any locking code for atomic variable access (it will +simply reject any attempt to make a variable or type atomic +if the atomic access cannot be achieved without such locking code). + +That being said, it is important to understand that you cannot +assume that the entire variable will always be accessed. Consider +this example: + +@quotation + +@example +type R is record + A,B,C,D : Character; +end record; +for R'Size use 32; +for R'Alignment use 4; + +RV : R; +pragma Atomic (RV); +X : Character; +... +X := RV.B; +@end example +@end quotation + +You cannot assume that the reference to @cite{RV.B} +will read the entire 32-bit +variable with a single load instruction. It is perfectly legitimate if +the hardware allows it to do a byte read of just the B field. This read +is still atomic, which is all the RM requires. GNAT can and does take +advantage of this, depending on the architecture and optimization level. +Any assumption to the contrary is non-portable and risky. Even if you +examine the assembly language and see a full 32-bit load, this might +change in a future version of the compiler. + +If your application requires that all accesses to @cite{RV} in this +example be full 32-bit loads, you need to make a copy for the access +as in: + +@quotation + +@example +declare + RV_Copy : constant R := RV; +begin + X := RV_Copy.B; +end; +@end example +@end quotation + +Now the reference to RV must read the whole variable. +Actually one can imagine some compiler which figures +out that the whole copy is not required (because only +the B field is actually accessed), but GNAT +certainly won't do that, and we don't know of any +compiler that would not handle this right, and the +above code will in practice work portably across +all architectures (that permit the Atomic declaration). + +The second issue with atomic variables has to do with +the possible requirement of generating synchronization +code. For more details on this, consult the sections on +the pragmas Enable/Disable_Atomic_Synchronization in the +GNAT Reference Manual. If performance is critical, and +such synchronization code is not required, it may be +useful to disable it. + +@node Passive Task Optimization,,Atomic Variables and Optimization,Performance Considerations +@anchor{gnat_ugn/gnat_and_program_execution id41}@anchor{23c}@anchor{gnat_ugn/gnat_and_program_execution passive-task-optimization}@anchor{23d} +@subsubsection Passive Task Optimization + + +@geindex Passive Task + +A passive task is one which is sufficiently simple that +in theory a compiler could recognize it an implement it +efficiently without creating a new thread. The original design +of Ada 83 had in mind this kind of passive task optimization, but +only a few Ada 83 compilers attempted it. The problem was that +it was difficult to determine the exact conditions under which +the optimization was possible. The result is a very fragile +optimization where a very minor change in the program can +suddenly silently make a task non-optimizable. + +With the revisiting of this issue in Ada 95, there was general +agreement that this approach was fundamentally flawed, and the +notion of protected types was introduced. When using protected +types, the restrictions are well defined, and you KNOW that the +operations will be optimized, and furthermore this optimized +performance is fully portable. + +Although it would theoretically be possible for GNAT to attempt to +do this optimization, but it really doesn't make sense in the +context of Ada 95, and none of the Ada 95 compilers implement +this optimization as far as we know. In particular GNAT never +attempts to perform this optimization. + +In any new Ada 95 code that is written, you should always +use protected types in place of tasks that might be able to +be optimized in this manner. +Of course this does not help if you have legacy Ada 83 code +that depends on this optimization, but it is unusual to encounter +a case where the performance gains from this optimization +are significant. + +Your program should work correctly without this optimization. If +you have performance problems, then the most practical +approach is to figure out exactly where these performance problems +arise, and update those particular tasks to be protected types. Note +that typically clients of the tasks who call entries, will not have +to be modified, only the task definition itself. + +@node Text_IO Suggestions,Reducing Size of Executables with Unused Subprogram/Data Elimination,Performance Considerations,Improving Performance +@anchor{gnat_ugn/gnat_and_program_execution text-io-suggestions}@anchor{23e}@anchor{gnat_ugn/gnat_and_program_execution id42}@anchor{23f} +@subsection @cite{Text_IO} Suggestions + + +@geindex Text_IO and performance + +The @cite{Ada.Text_IO} package has fairly high overheads due in part to +the requirement of maintaining page and line counts. If performance +is critical, a recommendation is to use @cite{Stream_IO} instead of +@cite{Text_IO} for volume output, since this package has less overhead. + +If @cite{Text_IO} must be used, note that by default output to the standard +output and standard error files is unbuffered (this provides better +behavior when output statements are used for debugging, or if the +progress of a program is observed by tracking the output, e.g. by +using the Unix @emph{tail -f} command to watch redirected output. + +If you are generating large volumes of output with @cite{Text_IO} and +performance is an important factor, use a designated file instead +of the standard output file, or change the standard output file to +be buffered using @cite{Interfaces.C_Streams.setvbuf}. + +@node Reducing Size of Executables with Unused Subprogram/Data Elimination,,Text_IO Suggestions,Improving Performance +@anchor{gnat_ugn/gnat_and_program_execution id43}@anchor{240}@anchor{gnat_ugn/gnat_and_program_execution reducing-size-of-executables-with-unused-subprogram-data-elimination}@anchor{241} +@subsection Reducing Size of Executables with Unused Subprogram/Data Elimination + + +@geindex Uunused subprogram/data elimination + +This section describes how you can eliminate unused subprograms and data from +your executable just by setting options at compilation time. + +@menu +* About unused subprogram/data elimination:: +* Compilation options:: +* Example of unused subprogram/data elimination:: + +@end menu + +@node About unused subprogram/data elimination,Compilation options,,Reducing Size of Executables with Unused Subprogram/Data Elimination +@anchor{gnat_ugn/gnat_and_program_execution id44}@anchor{242}@anchor{gnat_ugn/gnat_and_program_execution about-unused-subprogram-data-elimination}@anchor{243} +@subsubsection About unused subprogram/data elimination + + +By default, an executable contains all code and data of its composing objects +(directly linked or coming from statically linked libraries), even data or code +never used by this executable. + +This feature will allow you to eliminate such unused code from your +executable, making it smaller (in disk and in memory). + +This functionality is available on all Linux platforms except for the IA-64 +architecture and on all cross platforms using the ELF binary file format. +In both cases GNU binutils version 2.16 or later are required to enable it. + +@node Compilation options,Example of unused subprogram/data elimination,About unused subprogram/data elimination,Reducing Size of Executables with Unused Subprogram/Data Elimination +@anchor{gnat_ugn/gnat_and_program_execution id45}@anchor{244}@anchor{gnat_ugn/gnat_and_program_execution compilation-options}@anchor{245} +@subsubsection Compilation options + + +The operation of eliminating the unused code and data from the final executable +is directly performed by the linker. + +@geindex -ffunction-sections (gcc) + +@geindex -fdata-sections (gcc) + +In order to do this, it has to work with objects compiled with the +following options: +@emph{-ffunction-sections} @emph{-fdata-sections}. + +These options are usable with C and Ada files. +They will place respectively each +function or data in a separate section in the resulting object file. + +Once the objects and static libraries are created with these options, the +linker can perform the dead code elimination. You can do this by setting +the @emph{-Wl,--gc-sections} option to gcc command or in the +@emph{-largs} section of @emph{gnatmake}. This will perform a +garbage collection of code and data never referenced. + +If the linker performs a partial link (@emph{-r} linker option), then you +will need to provide the entry point using the @emph{-e} / @emph{--entry} +linker option. + +Note that objects compiled without the @emph{-ffunction-sections} and +@emph{-fdata-sections} options can still be linked with the executable. +However, no dead code elimination will be performed on those objects (they will +be linked as is). + +The GNAT static library is now compiled with -ffunction-sections and +-fdata-sections on some platforms. This allows you to eliminate the unused code +and data of the GNAT library from your executable. + +@node Example of unused subprogram/data elimination,,Compilation options,Reducing Size of Executables with Unused Subprogram/Data Elimination +@anchor{gnat_ugn/gnat_and_program_execution id46}@anchor{246}@anchor{gnat_ugn/gnat_and_program_execution example-of-unused-subprogram-data-elimination}@anchor{247} +@subsubsection Example of unused subprogram/data elimination + + +Here is a simple example: + +@quotation + +@example +with Aux; + +procedure Test is +begin + Aux.Used (10); +end Test; + +package Aux is + Used_Data : Integer; + Unused_Data : Integer; + + procedure Used (Data : Integer); + procedure Unused (Data : Integer); +end Aux; + +package body Aux is + procedure Used (Data : Integer) is + begin + Used_Data := Data; + end Used; + + procedure Unused (Data : Integer) is + begin + Unused_Data := Data; + end Unused; +end Aux; +@end example +@end quotation + +@cite{Unused} and @cite{Unused_Data} are never referenced in this code +excerpt, and hence they may be safely removed from the final executable. + +@quotation + +@example +$ gnatmake test + +$ nm test | grep used +020015f0 T aux__unused +02005d88 B aux__unused_data +020015cc T aux__used +02005d84 B aux__used_data + +$ gnatmake test -cargs -fdata-sections -ffunction-sections \\ + -largs -Wl,--gc-sections + +$ nm test | grep used +02005350 T aux__used +0201ffe0 B aux__used_data +@end example +@end quotation + +It can be observed that the procedure @cite{Unused} and the object +@cite{Unused_Data} are removed by the linker when using the +appropriate options. + +@geindex Overflow checks + +@geindex Checks (overflow) + + +@node Overflow Check Handling in GNAT,Performing Dimensionality Analysis in GNAT,Improving Performance,GNAT and Program Execution +@anchor{gnat_ugn/gnat_and_program_execution id54}@anchor{1f3}@anchor{gnat_ugn/gnat_and_program_execution overflow-check-handling-in-gnat}@anchor{29} +@section Overflow Check Handling in GNAT + + +This section explains how to control the handling of overflow checks. + +@menu +* Background:: +* Overflow Checking Modes in GNAT:: +* Specifying the Desired Mode:: +* Default Settings:: +* Implementation Notes:: + +@end menu + +@node Background,Overflow Checking Modes in GNAT,,Overflow Check Handling in GNAT +@anchor{gnat_ugn/gnat_and_program_execution id55}@anchor{248}@anchor{gnat_ugn/gnat_and_program_execution background}@anchor{249} +@subsection Background + + +Overflow checks are checks that the compiler may make to ensure +that intermediate results are not out of range. For example: + +@quotation + +@example +A : Integer; +... +A := A + 1; +@end example +@end quotation + +If @cite{A} has the value @cite{Integer'Last}, then the addition may cause +overflow since the result is out of range of the type @cite{Integer}. +In this case @cite{Constraint_Error} will be raised if checks are +enabled. + +A trickier situation arises in examples like the following: + +@quotation + +@example +A, C : Integer; +... +A := (A + 1) + C; +@end example +@end quotation + +where @cite{A} is @cite{Integer'Last} and @cite{C} is @cite{-1}. +Now the final result of the expression on the right hand side is +@cite{Integer'Last} which is in range, but the question arises whether the +intermediate addition of @cite{(A + 1)} raises an overflow error. + +The (perhaps surprising) answer is that the Ada language +definition does not answer this question. Instead it leaves +it up to the implementation to do one of two things if overflow +checks are enabled. + + +@itemize * + +@item +raise an exception (@cite{Constraint_Error}), or + +@item +yield the correct mathematical result which is then used in +subsequent operations. +@end itemize + +If the compiler chooses the first approach, then the assignment of this +example will indeed raise @cite{Constraint_Error} if overflow checking is +enabled, or result in erroneous execution if overflow checks are suppressed. + +But if the compiler +chooses the second approach, then it can perform both additions yielding +the correct mathematical result, which is in range, so no exception +will be raised, and the right result is obtained, regardless of whether +overflow checks are suppressed. + +Note that in the first example an +exception will be raised in either case, since if the compiler +gives the correct mathematical result for the addition, it will +be out of range of the target type of the assignment, and thus +fails the range check. + +This lack of specified behavior in the handling of overflow for +intermediate results is a source of non-portability, and can thus +be problematic when programs are ported. Most typically this arises +in a situation where the original compiler did not raise an exception, +and then the application is moved to a compiler where the check is +performed on the intermediate result and an unexpected exception is +raised. + +Furthermore, when using Ada 2012's preconditions and other +assertion forms, another issue arises. Consider: + +@quotation + +@example +procedure P (A, B : Integer) with + Pre => A + B <= Integer'Last; +@end example +@end quotation + +One often wants to regard arithmetic in a context like this from +a mathematical point of view. So for example, if the two actual parameters +for a call to @cite{P} are both @cite{Integer'Last}, then +the precondition should be regarded as False. If we are executing +in a mode with run-time checks enabled for preconditions, then we would +like this precondition to fail, rather than raising an exception +because of the intermediate overflow. + +However, the language definition leaves the specification of +whether the above condition fails (raising @cite{Assert_Error}) or +causes an intermediate overflow (raising @cite{Constraint_Error}) +up to the implementation. + +The situation is worse in a case such as the following: + +@quotation + +@example +procedure Q (A, B, C : Integer) with + Pre => A + B + C <= Integer'Last; +@end example +@end quotation + +Consider the call + +@quotation + +@example +Q (A => Integer'Last, B => 1, C => -1); +@end example +@end quotation + +From a mathematical point of view the precondition +is True, but at run time we may (but are not guaranteed to) get an +exception raised because of the intermediate overflow (and we really +would prefer this precondition to be considered True at run time). + +@node Overflow Checking Modes in GNAT,Specifying the Desired Mode,Background,Overflow Check Handling in GNAT +@anchor{gnat_ugn/gnat_and_program_execution id56}@anchor{24a}@anchor{gnat_ugn/gnat_and_program_execution overflow-checking-modes-in-gnat}@anchor{24b} +@subsection Overflow Checking Modes in GNAT + + +To deal with the portability issue, and with the problem of +mathematical versus run-time interpretation of the expressions in +assertions, GNAT provides comprehensive control over the handling +of intermediate overflow. GNAT can operate in three modes, and +furthemore, permits separate selection of operating modes for +the expressions within assertions (here the term 'assertions' +is used in the technical sense, which includes preconditions and so forth) +and for expressions appearing outside assertions. + +The three modes are: + + +@itemize * + +@item +@emph{Use base type for intermediate operations} (@cite{STRICT}) + +In this mode, all intermediate results for predefined arithmetic +operators are computed using the base type, and the result must +be in range of the base type. If this is not the +case then either an exception is raised (if overflow checks are +enabled) or the execution is erroneous (if overflow checks are suppressed). +This is the normal default mode. + +@item +@emph{Most intermediate overflows avoided} (@cite{MINIMIZED}) + +In this mode, the compiler attempts to avoid intermediate overflows by +using a larger integer type, typically @cite{Long_Long_Integer}, +as the type in which arithmetic is +performed for predefined arithmetic operators. This may be slightly more +expensive at +run time (compared to suppressing intermediate overflow checks), though +the cost is negligible on modern 64-bit machines. For the examples given +earlier, no intermediate overflows would have resulted in exceptions, +since the intermediate results are all in the range of +@cite{Long_Long_Integer} (typically 64-bits on nearly all implementations +of GNAT). In addition, if checks are enabled, this reduces the number of +checks that must be made, so this choice may actually result in an +improvement in space and time behavior. + +However, there are cases where @cite{Long_Long_Integer} is not large +enough, consider the following example: + +@quotation + +@example +procedure R (A, B, C, D : Integer) with + Pre => (A**2 * B**2) / (C**2 * D**2) <= 10; +@end example +@end quotation + +where @cite{A} = @cite{B} = @cite{C} = @cite{D} = @cite{Integer'Last}. +Now the intermediate results are +out of the range of @cite{Long_Long_Integer} even though the final result +is in range and the precondition is True (from a mathematical point +of view). In such a case, operating in this mode, an overflow occurs +for the intermediate computation (which is why this mode +says @emph{most} intermediate overflows are avoided). In this case, +an exception is raised if overflow checks are enabled, and the +execution is erroneous if overflow checks are suppressed. + +@item +@emph{All intermediate overflows avoided} (@cite{ELIMINATED}) + +In this mode, the compiler avoids all intermediate overflows +by using arbitrary precision arithmetic as required. In this +mode, the above example with @cite{A**2 * B**2} would +not cause intermediate overflow, because the intermediate result +would be evaluated using sufficient precision, and the result +of evaluating the precondition would be True. + +This mode has the advantage of avoiding any intermediate +overflows, but at the expense of significant run-time overhead, +including the use of a library (included automatically in this +mode) for multiple-precision arithmetic. + +This mode provides cleaner semantics for assertions, since now +the run-time behavior emulates true arithmetic behavior for the +predefined arithmetic operators, meaning that there is never a +conflict between the mathematical view of the assertion, and its +run-time behavior. + +Note that in this mode, the behavior is unaffected by whether or +not overflow checks are suppressed, since overflow does not occur. +It is possible for gigantic intermediate expressions to raise +@cite{Storage_Error} as a result of attempting to compute the +results of such expressions (e.g. @cite{Integer'Last ** Integer'Last}) +but overflow is impossible. +@end itemize + +Note that these modes apply only to the evaluation of predefined +arithmetic, membership, and comparison operators for signed integer +aritmetic. + +For fixed-point arithmetic, checks can be suppressed. But if checks +are enabled +then fixed-point values are always checked for overflow against the +base type for intermediate expressions (that is such checks always +operate in the equivalent of @cite{STRICT} mode). + +For floating-point, on nearly all architectures, @cite{Machine_Overflows} +is False, and IEEE infinities are generated, so overflow exceptions +are never raised. If you want to avoid infinities, and check that +final results of expressions are in range, then you can declare a +constrained floating-point type, and range checks will be carried +out in the normal manner (with infinite values always failing all +range checks). + +@node Specifying the Desired Mode,Default Settings,Overflow Checking Modes in GNAT,Overflow Check Handling in GNAT +@anchor{gnat_ugn/gnat_and_program_execution specifying-the-desired-mode}@anchor{fd}@anchor{gnat_ugn/gnat_and_program_execution id57}@anchor{24c} +@subsection Specifying the Desired Mode + + +@geindex pragma Overflow_Mode + +The desired mode of for handling intermediate overflow can be specified using +either the @cite{Overflow_Mode} pragma or an equivalent compiler switch. +The pragma has the form + +@quotation + +@example +pragma Overflow_Mode ([General =>] MODE [, [Assertions =>] MODE]); +@end example +@end quotation + +where @cite{MODE} is one of + + +@itemize * + +@item +@cite{STRICT}: intermediate overflows checked (using base type) + +@item +@cite{MINIMIZED}: minimize intermediate overflows + +@item +@cite{ELIMINATED}: eliminate intermediate overflows +@end itemize + +The case is ignored, so @cite{MINIMIZED}, @cite{Minimized} and +@cite{minimized} all have the same effect. + +If only the @cite{General} parameter is present, then the given @cite{MODE} +applies +to expressions both within and outside assertions. If both arguments +are present, then @cite{General} applies to expressions outside assertions, +and @cite{Assertions} applies to expressions within assertions. For example: + +@quotation + +@example +pragma Overflow_Mode + (General => Minimized, Assertions => Eliminated); +@end example +@end quotation + +specifies that general expressions outside assertions be evaluated +in 'minimize intermediate overflows' mode, and expressions within +assertions be evaluated in 'eliminate intermediate overflows' mode. +This is often a reasonable choice, avoiding excessive overhead +outside assertions, but assuring a high degree of portability +when importing code from another compiler, while incurring +the extra overhead for assertion expressions to ensure that +the behavior at run time matches the expected mathematical +behavior. + +The @cite{Overflow_Mode} pragma has the same scoping and placement +rules as pragma @cite{Suppress}, so it can occur either as a +configuration pragma, specifying a default for the whole +program, or in a declarative scope, where it applies to the +remaining declarations and statements in that scope. + +Note that pragma @cite{Overflow_Mode} does not affect whether +overflow checks are enabled or suppressed. It only controls the +method used to compute intermediate values. To control whether +overflow checking is enabled or suppressed, use pragma @cite{Suppress} +or @cite{Unsuppress} in the usual manner + +@geindex -gnato? (gcc) + +@geindex -gnato?? (gcc) + +Additionally, a compiler switch @emph{-gnato?} or @emph{-gnato??} +can be used to control the checking mode default (which can be subsequently +overridden using pragmas). + +Here @code{?} is one of the digits @code{1} through @code{3}: + +@quotation + + +@multitable {xxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item + +@code{1} + +@tab + +use base type for intermediate operations (@cite{STRICT}) + +@item + +@code{2} + +@tab + +minimize intermediate overflows (@cite{MINIMIZED}) + +@item + +@code{3} + +@tab + +eliminate intermediate overflows (@cite{ELIMINATED}) + +@end multitable + +@end quotation + +As with the pragma, if only one digit appears then it applies to all +cases; if two digits are given, then the first applies outside +assertions, and the second within assertions. Thus the equivalent +of the example pragma above would be +@emph{-gnato23}. + +If no digits follow the @emph{-gnato}, then it is equivalent to +@emph{-gnato11}, +causing all intermediate operations to be computed using the base +type (@cite{STRICT} mode). + +In addition to setting the mode used for computation of intermediate +results, the @cite{-gnato} switch also enables overflow checking (which +is suppressed by default). It thus combines the effect of using +a pragma @cite{Overflow_Mode} and pragma @cite{Unsuppress}. + +@node Default Settings,Implementation Notes,Specifying the Desired Mode,Overflow Check Handling in GNAT +@anchor{gnat_ugn/gnat_and_program_execution id58}@anchor{24d}@anchor{gnat_ugn/gnat_and_program_execution default-settings}@anchor{24e} +@subsection Default Settings + + +The default mode for overflow checks is + +@quotation + +@example +General => Strict +@end example +@end quotation + +which causes all computations both inside and outside assertions to use +the base type. In addition overflow checks are suppressed. + +This retains compatibility with previous versions of +GNAT which suppressed overflow checks by default and always +used the base type for computation of intermediate results. + +The switch @emph{-gnato} (with no digits following) is equivalent to +.. index:: -gnato (gcc) + +@quotation + +@example +General => Strict +@end example +@end quotation + +which causes overflow checking of all intermediate overflows +both inside and outside assertions against the base type. +This provides compatibility +with this switch as implemented in previous versions of GNAT. + +The pragma @cite{Suppress (Overflow_Check)} disables overflow +checking, but it has no effect on the method used for computing +intermediate results. + +The pragma @cite{Unsuppress (Overflow_Check)} enables overflow +checking, but it has no effect on the method used for computing +intermediate results. + +@node Implementation Notes,,Default Settings,Overflow Check Handling in GNAT +@anchor{gnat_ugn/gnat_and_program_execution implementation-notes}@anchor{24f}@anchor{gnat_ugn/gnat_and_program_execution id59}@anchor{250} +@subsection Implementation Notes + + +In practice on typical 64-bit machines, the @cite{MINIMIZED} mode is +reasonably efficient, and can be generally used. It also helps +to ensure compatibility with code imported from some other +compiler to GNAT. + +Setting all intermediate overflows checking (@cite{CHECKED} mode) +makes sense if you want to +make sure that your code is compatible with any other possible +Ada implementation. This may be useful in ensuring portability +for code that is to be exported to some other compiler than GNAT. + +The Ada standard allows the reassociation of expressions at +the same precedence level if no parentheses are present. For +example, @cite{A+B+C} parses as though it were @cite{(A+B)+C}, but +the compiler can reintepret this as @cite{A+(B+C)}, possibly +introducing or eliminating an overflow exception. The GNAT +compiler never takes advantage of this freedom, and the +expression @cite{A+B+C} will be evaluated as @cite{(A+B)+C}. +If you need the other order, you can write the parentheses +explicitly @cite{A+(B+C)} and GNAT will respect this order. + +The use of @cite{ELIMINATED} mode will cause the compiler to +automatically include an appropriate arbitrary precision +integer arithmetic package. The compiler will make calls +to this package, though only in cases where it cannot be +sure that @cite{Long_Long_Integer} is sufficient to guard against +intermediate overflows. This package does not use dynamic +alllocation, but it does use the secondary stack, so an +appropriate secondary stack package must be present (this +is always true for standard full Ada, but may require +specific steps for restricted run times such as ZFP). + +Although @cite{ELIMINATED} mode causes expressions to use arbitrary +precision arithmetic, avoiding overflow, the final result +must be in an appropriate range. This is true even if the +final result is of type @cite{[Long_[Long_]]Integer'Base}, which +still has the same bounds as its associated constrained +type at run-time. + +Currently, the @cite{ELIMINATED} mode is only available on target +platforms for which @cite{Long_Long_Integer} is 64-bits (nearly all GNAT +platforms). + +@node Performing Dimensionality Analysis in GNAT,Stack Related Facilities,Overflow Check Handling in GNAT,GNAT and Program Execution +@anchor{gnat_ugn/gnat_and_program_execution performing-dimensionality-analysis-in-gnat}@anchor{2a}@anchor{gnat_ugn/gnat_and_program_execution id60}@anchor{1f4} +@section Performing Dimensionality Analysis in GNAT + + +@geindex Dimensionality analysis + +The GNAT compiler supports dimensionality checking. The user can +specify physical units for objects, and the compiler will verify that uses +of these objects are compatible with their dimensions, in a fashion that is +familiar to engineering practice. The dimensions of algebraic expressions +(including powers with static exponents) are computed from their constituents. + +@geindex Dimension_System aspect + +@geindex Dimension aspect + +This feature depends on Ada 2012 aspect specifications, and is available from +version 7.0.1 of GNAT onwards. +The GNAT-specific aspect @cite{Dimension_System} +allows you to define a system of units; the aspect @cite{Dimension} +then allows the user to declare dimensioned quantities within a given system. +(These aspects are described in the @emph{Implementation Defined Aspects} +chapter of the @emph{GNAT Reference Manual}). + +The major advantage of this model is that it does not require the declaration of +multiple operators for all possible combinations of types: it is only necessary +to use the proper subtypes in object declarations. + +@geindex System.Dim.Mks package (GNAT library) + +@geindex MKS_Type type + +The simplest way to impose dimensionality checking on a computation is to make +use of the package @cite{System.Dim.Mks}, +which is part of the GNAT library. This +package defines a floating-point type @cite{MKS_Type}, +for which a sequence of +dimension names are specified, together with their conventional abbreviations. +The following should be read together with the full specification of the +package, in file @code{s-dimmks.ads}. + +@quotation + +@geindex s-dimmks.ads file + +@example +type Mks_Type is new Long_Long_Float + with + Dimension_System => ( + (Unit_Name => Meter, Unit_Symbol => 'm', Dim_Symbol => 'L'), + (Unit_Name => Kilogram, Unit_Symbol => "kg", Dim_Symbol => 'M'), + (Unit_Name => Second, Unit_Symbol => 's', Dim_Symbol => 'T'), + (Unit_Name => Ampere, Unit_Symbol => 'A', Dim_Symbol => 'I'), + (Unit_Name => Kelvin, Unit_Symbol => 'K', Dim_Symbol => "Theta"), + (Unit_Name => Mole, Unit_Symbol => "mol", Dim_Symbol => 'N'), + (Unit_Name => Candela, Unit_Symbol => "cd", Dim_Symbol => 'J')); +@end example +@end quotation + +The package then defines a series of subtypes that correspond to these +conventional units. For example: + +@quotation + +@example +subtype Length is Mks_Type + with + Dimension => (Symbol => 'm', Meter => 1, others => 0); +@end example +@end quotation + +and similarly for @cite{Mass}, @cite{Time}, @cite{Electric_Current}, +@cite{Thermodynamic_Temperature}, @cite{Amount_Of_Substance}, and +@cite{Luminous_Intensity} (the standard set of units of the SI system). + +The package also defines conventional names for values of each unit, for +example: + +@quotation + +@c code-block":: ada +@c +@c m : constant Length := 1.0; +@c kg : constant Mass := 1.0; +@c s : constant Time := 1.0; +@c A : constant Electric_Current := 1.0; +@end quotation + +as well as useful multiples of these units: + +@quotation + +@example + cm : constant Length := 1.0E-02; + g : constant Mass := 1.0E-03; + min : constant Time := 60.0; + day : constant Time := 60.0 * 24.0 * min; +... +@end example +@end quotation + +Using this package, you can then define a derived unit by +providing the aspect that +specifies its dimensions within the MKS system, as well as the string to +be used for output of a value of that unit: + +@quotation + +@example +subtype Acceleration is Mks_Type + with Dimension => ("m/sec^2", + Meter => 1, + Second => -2, + others => 0); +@end example +@end quotation + +Here is a complete example of use: + +@quotation + +@example +with System.Dim.MKS; use System.Dim.Mks; +with System.Dim.Mks_IO; use System.Dim.Mks_IO; +with Text_IO; use Text_IO; +procedure Free_Fall is + subtype Acceleration is Mks_Type + with Dimension => ("m/sec^2", 1, 0, -2, others => 0); + G : constant acceleration := 9.81 * m / (s ** 2); + T : Time := 10.0*s; + Distance : Length; + +begin + Put ("Gravitational constant: "); + Put (G, Aft => 2, Exp => 0); Put_Line (""); + Distance := 0.5 * G * T ** 2; + Put ("distance travelled in 10 seconds of free fall "); + Put (Distance, Aft => 2, Exp => 0); + Put_Line (""); +end Free_Fall; +@end example +@end quotation + +Execution of this program yields: + +@quotation + +@example +Gravitational constant: 9.81 m/sec^2 +distance travelled in 10 seconds of free fall 490.50 m +@end example +@end quotation + +However, incorrect assignments such as: + +@quotation + +@example +Distance := 5.0; +Distance := 5.0 * kg: +@end example +@end quotation + +are rejected with the following diagnoses: + +@quotation + +@example +Distance := 5.0; + >>> dimensions mismatch in assignment + >>> left-hand side has dimension [L] + >>> right-hand side is dimensionless + +Distance := 5.0 * kg: + >>> dimensions mismatch in assignment + >>> left-hand side has dimension [L] + >>> right-hand side has dimension [M] +@end example +@end quotation + +The dimensions of an expression are properly displayed, even if there is +no explicit subtype for it. If we add to the program: + +@quotation + +@example +Put ("Final velocity: "); +Put (G * T, Aft =>2, Exp =>0); +Put_Line (""); +@end example +@end quotation + +then the output includes: + +@quotation + +@example +Final velocity: 98.10 m.s**(-1) +@end example +@end quotation + +@node Stack Related Facilities,Memory Management Issues,Performing Dimensionality Analysis in GNAT,GNAT and Program Execution +@anchor{gnat_ugn/gnat_and_program_execution id61}@anchor{1f5}@anchor{gnat_ugn/gnat_and_program_execution stack-related-facilities}@anchor{2b} +@section Stack Related Facilities + + +This section describes some useful tools associated with stack +checking and analysis. In +particular, it deals with dynamic and static stack usage measurements. + +@menu +* Stack Overflow Checking:: +* Static Stack Usage Analysis:: +* Dynamic Stack Usage Analysis:: + +@end menu + +@node Stack Overflow Checking,Static Stack Usage Analysis,,Stack Related Facilities +@anchor{gnat_ugn/gnat_and_program_execution id62}@anchor{251}@anchor{gnat_ugn/gnat_and_program_execution stack-overflow-checking}@anchor{f9} +@subsection Stack Overflow Checking + + +@geindex Stack Overflow Checking + +@geindex -fstack-check (gcc) + +For most operating systems, @emph{gcc} does not perform stack overflow +checking by default. This means that if the main environment task or +some other task exceeds the available stack space, then unpredictable +behavior will occur. Most native systems offer some level of protection by +adding a guard page at the end of each task stack. This mechanism is usually +not enough for dealing properly with stack overflow situations because +a large local variable could "jump" above the guard page. +Furthermore, when the +guard page is hit, there may not be any space left on the stack for executing +the exception propagation code. Enabling stack checking avoids +such situations. + +To activate stack checking, compile all units with the gcc option +@cite{-fstack-check}. For example: + +@quotation + +@example +$ gcc -c -fstack-check package1.adb +@end example +@end quotation + +Units compiled with this option will generate extra instructions to check +that any use of the stack (for procedure calls or for declaring local +variables in declare blocks) does not exceed the available stack space. +If the space is exceeded, then a @cite{Storage_Error} exception is raised. + +For declared tasks, the stack size is controlled by the size +given in an applicable @cite{Storage_Size} pragma or by the value specified +at bind time with @code{-d} (@ref{123,,Switches for gnatbind}) or is set to +the default size as defined in the GNAT runtime otherwise. + +@geindex GNAT_STACK_LIMIT + +For the environment task, the stack size depends on +system defaults and is unknown to the compiler. Stack checking +may still work correctly if a fixed +size stack is allocated, but this cannot be guaranteed. +To ensure that a clean exception is signalled for stack +overflow, set the environment variable +@geindex GNAT_STACK_LIMIT +@geindex environment variable; GNAT_STACK_LIMIT +@code{GNAT_STACK_LIMIT} to indicate the maximum +stack area that can be used, as in: + +@quotation + +@example +$ SET GNAT_STACK_LIMIT 1600 +@end example +@end quotation + +The limit is given in kilobytes, so the above declaration would +set the stack limit of the environment task to 1.6 megabytes. +Note that the only purpose of this usage is to limit the amount +of stack used by the environment task. If it is necessary to +increase the amount of stack for the environment task, then this +is an operating systems issue, and must be addressed with the +appropriate operating systems commands. + +@node Static Stack Usage Analysis,Dynamic Stack Usage Analysis,Stack Overflow Checking,Stack Related Facilities +@anchor{gnat_ugn/gnat_and_program_execution static-stack-usage-analysis}@anchor{fa}@anchor{gnat_ugn/gnat_and_program_execution id63}@anchor{252} +@subsection Static Stack Usage Analysis + + +@geindex Static Stack Usage Analysis + +@geindex -fstack-usage + +A unit compiled with @code{-fstack-usage} will generate an extra file +that specifies +the maximum amount of stack used, on a per-function basis. +The file has the same +basename as the target object file with a @code{.su} extension. +Each line of this file is made up of three fields: + + +@itemize * + +@item +The name of the function. + +@item +A number of bytes. + +@item +One or more qualifiers: @cite{static}, @cite{dynamic}, @cite{bounded}. +@end itemize + +The second field corresponds to the size of the known part of the function +frame. + +The qualifier @cite{static} means that the function frame size +is purely static. +It usually means that all local variables have a static size. +In this case, the second field is a reliable measure of the function stack +utilization. + +The qualifier @cite{dynamic} means that the function frame size is not static. +It happens mainly when some local variables have a dynamic size. When this +qualifier appears alone, the second field is not a reliable measure +of the function stack analysis. When it is qualified with @cite{bounded}, it +means that the second field is a reliable maximum of the function stack +utilization. + +A unit compiled with @code{-Wstack-usage} will issue a warning for each +subprogram whose stack usage might be larger than the specified amount of +bytes. The wording is in keeping with the qualifier documented above. + +@node Dynamic Stack Usage Analysis,,Static Stack Usage Analysis,Stack Related Facilities +@anchor{gnat_ugn/gnat_and_program_execution id64}@anchor{253}@anchor{gnat_ugn/gnat_and_program_execution dynamic-stack-usage-analysis}@anchor{125} +@subsection Dynamic Stack Usage Analysis + + +It is possible to measure the maximum amount of stack used by a task, by +adding a switch to @emph{gnatbind}, as: + +@quotation + +@example +$ gnatbind -u0 file +@end example +@end quotation + +With this option, at each task termination, its stack usage is output on +@code{stderr}. +It is not always convenient to output the stack usage when the program +is still running. Hence, it is possible to delay this output until program +termination. for a given number of tasks specified as the argument of the +@code{-u} option. For instance: + +@quotation + +@example +$ gnatbind -u100 file +@end example +@end quotation + +will buffer the stack usage information of the first 100 tasks to terminate and +output this info at program termination. Results are displayed in four +columns: + +@quotation + +@example +Index | Task Name | Stack Size | Stack Usage +@end example +@end quotation + +where: + + +@itemize * + +@item +@emph{Index} is a number associated with each task. + +@item +@emph{Task Name} is the name of the task analyzed. + +@item +@emph{Stack Size} is the maximum size for the stack. + +@item +@emph{Stack Usage} is the measure done by the stack analyzer. +In order to prevent overflow, the stack +is not entirely analyzed, and it's not possible to know exactly how +much has actually been used. +@end itemize + +The environment task stack, e.g., the stack that contains the main unit, is +only processed when the environment variable GNAT_STACK_LIMIT is set. + +The package @cite{GNAT.Task_Stack_Usage} provides facilities to get +stack usage reports at run-time. See its body for the details. + +@node Memory Management Issues,,Stack Related Facilities,GNAT and Program Execution +@anchor{gnat_ugn/gnat_and_program_execution id65}@anchor{1f6}@anchor{gnat_ugn/gnat_and_program_execution memory-management-issues}@anchor{2c} +@section Memory Management Issues + + +This section describes some useful memory pools provided in the GNAT library +and in particular the GNAT Debug Pool facility, which can be used to detect +incorrect uses of access values (including 'dangling references'). + + +@menu +* Some Useful Memory Pools:: +* The GNAT Debug Pool Facility:: + +@end menu + +@node Some Useful Memory Pools,The GNAT Debug Pool Facility,,Memory Management Issues +@anchor{gnat_ugn/gnat_and_program_execution id66}@anchor{254}@anchor{gnat_ugn/gnat_and_program_execution some-useful-memory-pools}@anchor{255} +@subsection Some Useful Memory Pools + + +@geindex Memory Pool + +@geindex storage +@geindex pool + +The @cite{System.Pool_Global} package offers the Unbounded_No_Reclaim_Pool +storage pool. Allocations use the standard system call @cite{malloc} while +deallocations use the standard system call @cite{free}. No reclamation is +performed when the pool goes out of scope. For performance reasons, the +standard default Ada allocators/deallocators do not use any explicit storage +pools but if they did, they could use this storage pool without any change in +behavior. That is why this storage pool is used when the user +manages to make the default implicit allocator explicit as in this example: + +@quotation + +@example +type T1 is access Something; + -- no Storage pool is defined for T2 + +type T2 is access Something_Else; +for T2'Storage_Pool use T1'Storage_Pool; +-- the above is equivalent to +for T2'Storage_Pool use System.Pool_Global.Global_Pool_Object; +@end example +@end quotation + +The @cite{System.Pool_Local} package offers the Unbounded_Reclaim_Pool storage +pool. The allocation strategy is similar to @cite{Pool_Local}'s +except that the all +storage allocated with this pool is reclaimed when the pool object goes out of +scope. This pool provides a explicit mechanism similar to the implicit one +provided by several Ada 83 compilers for allocations performed through a local +access type and whose purpose was to reclaim memory when exiting the +scope of a given local access. As an example, the following program does not +leak memory even though it does not perform explicit deallocation: + +@quotation + +@example +with System.Pool_Local; +procedure Pooloc1 is + procedure Internal is + type A is access Integer; + X : System.Pool_Local.Unbounded_Reclaim_Pool; + for A'Storage_Pool use X; + v : A; + begin + for I in 1 .. 50 loop + v := new Integer; + end loop; + end Internal; +begin + for I in 1 .. 100 loop + Internal; + end loop; +end Pooloc1; +@end example +@end quotation + +The @cite{System.Pool_Size} package implements the Stack_Bounded_Pool used when +@cite{Storage_Size} is specified for an access type. +The whole storage for the pool is +allocated at once, usually on the stack at the point where the access type is +elaborated. It is automatically reclaimed when exiting the scope where the +access type is defined. This package is not intended to be used directly by the +user and it is implicitly used for each such declaration: + +@quotation + +@example +type T1 is access Something; +for T1'Storage_Size use 10_000; +@end example +@end quotation + +@node The GNAT Debug Pool Facility,,Some Useful Memory Pools,Memory Management Issues +@anchor{gnat_ugn/gnat_and_program_execution id67}@anchor{256}@anchor{gnat_ugn/gnat_and_program_execution the-gnat-debug-pool-facility}@anchor{257} +@subsection The GNAT Debug Pool Facility + + +@geindex Debug Pool + +@geindex storage +@geindex pool +@geindex memory corruption + +The use of unchecked deallocation and unchecked conversion can easily +lead to incorrect memory references. The problems generated by such +references are usually difficult to tackle because the symptoms can be +very remote from the origin of the problem. In such cases, it is +very helpful to detect the problem as early as possible. This is the +purpose of the Storage Pool provided by @cite{GNAT.Debug_Pools}. + +In order to use the GNAT specific debugging pool, the user must +associate a debug pool object with each of the access types that may be +related to suspected memory problems. See Ada Reference Manual 13.11. + +@quotation + +@example +type Ptr is access Some_Type; +Pool : GNAT.Debug_Pools.Debug_Pool; +for Ptr'Storage_Pool use Pool; +@end example +@end quotation + +@cite{GNAT.Debug_Pools} is derived from a GNAT-specific kind of +pool: the @cite{Checked_Pool}. Such pools, like standard Ada storage pools, +allow the user to redefine allocation and deallocation strategies. They +also provide a checkpoint for each dereference, through the use of +the primitive operation @cite{Dereference} which is implicitly called at +each dereference of an access value. + +Once an access type has been associated with a debug pool, operations on +values of the type may raise four distinct exceptions, +which correspond to four potential kinds of memory corruption: + + +@itemize * + +@item +@cite{GNAT.Debug_Pools.Accessing_Not_Allocated_Storage} + +@item +@cite{GNAT.Debug_Pools.Accessing_Deallocated_Storage} + +@item +@cite{GNAT.Debug_Pools.Freeing_Not_Allocated_Storage} + +@item +@cite{GNAT.Debug_Pools.Freeing_Deallocated_Storage} +@end itemize + +For types associated with a Debug_Pool, dynamic allocation is performed using +the standard GNAT allocation routine. References to all allocated chunks of +memory are kept in an internal dictionary. Several deallocation strategies are +provided, whereupon the user can choose to release the memory to the system, +keep it allocated for further invalid access checks, or fill it with an easily +recognizable pattern for debug sessions. The memory pattern is the old IBM +hexadecimal convention: @cite{16#DEADBEEF#}. + +See the documentation in the file g-debpoo.ads for more information on the +various strategies. + +Upon each dereference, a check is made that the access value denotes a +properly allocated memory location. Here is a complete example of use of +@cite{Debug_Pools}, that includes typical instances of memory corruption: + +@quotation + +@example +with Gnat.Io; use Gnat.Io; +with Unchecked_Deallocation; +with Unchecked_Conversion; +with GNAT.Debug_Pools; +with System.Storage_Elements; +with Ada.Exceptions; use Ada.Exceptions; +procedure Debug_Pool_Test is + + type T is access Integer; + type U is access all T; + + P : GNAT.Debug_Pools.Debug_Pool; + for T'Storage_Pool use P; -@c ****************************** + procedure Free is new Unchecked_Deallocation (Integer, T); + function UC is new Unchecked_Conversion (U, T); + A, B : aliased T; -@c ************************************** -@node Platform-Specific Information for the Run-Time Libraries -@appendix Platform-Specific Information for the Run-Time Libraries -@cindex Tasking and threads libraries -@cindex Threads libraries and tasking -@cindex Run-time libraries (platform-specific information) + procedure Info is new GNAT.Debug_Pools.Print_Info(Put_Line); + +begin + Info (P); + A := new Integer; + B := new Integer; + B := A; + Info (P); + Free (A); + begin + Put_Line (Integer'Image(B.all)); + exception + when E : others => Put_Line ("raised: " & Exception_Name (E)); + end; + begin + Free (B); + exception + when E : others => Put_Line ("raised: " & Exception_Name (E)); + end; + B := UC(A'Access); + begin + Put_Line (Integer'Image(B.all)); + exception + when E : others => Put_Line ("raised: " & Exception_Name (E)); + end; + begin + Free (B); + exception + when E : others => Put_Line ("raised: " & Exception_Name (E)); + end; + Info (P); +end Debug_Pool_Test; +@end example +@end quotation + +The debug pool mechanism provides the following precise diagnostics on the +execution of this erroneous program: + +@quotation + +@example +Debug Pool info: + Total allocated bytes : 0 + Total deallocated bytes : 0 + Current Water Mark: 0 + High Water Mark: 0 + +Debug Pool info: + Total allocated bytes : 8 + Total deallocated bytes : 0 + Current Water Mark: 8 + High Water Mark: 8 + +raised: GNAT.DEBUG_POOLS.ACCESSING_DEALLOCATED_STORAGE +raised: GNAT.DEBUG_POOLS.FREEING_DEALLOCATED_STORAGE +raised: GNAT.DEBUG_POOLS.ACCESSING_NOT_ALLOCATED_STORAGE +raised: GNAT.DEBUG_POOLS.FREEING_NOT_ALLOCATED_STORAGE +Debug Pool info: + Total allocated bytes : 8 + Total deallocated bytes : 4 + Current Water Mark: 4 + High Water Mark: 8 +@end example +@end quotation + + +@c -- Non-breaking space in running text +@c -- E.g. Ada |nbsp| 95 + +@node Platform-Specific Information,Example of Binder Output File,GNAT and Program Execution,Top +@anchor{gnat_ugn/platform_specific_information platform-specific-information}@anchor{f}@anchor{gnat_ugn/platform_specific_information doc}@anchor{258}@anchor{gnat_ugn/platform_specific_information id1}@anchor{259} +@chapter Platform-Specific Information + + +This appendix contains information relating to the implementation +of run-time libraries on various platforms and also covers +topics related to the GNAT implementation on Windows and Mac OS. + +@menu +* Run-Time Libraries:: +* Specifying a Run-Time Library:: +* Microsoft Windows Topics:: +* Mac OS Topics:: + +@end menu + +@node Run-Time Libraries,Specifying a Run-Time Library,,Platform-Specific Information +@anchor{gnat_ugn/platform_specific_information id2}@anchor{25a}@anchor{gnat_ugn/platform_specific_information run-time-libraries}@anchor{2d} +@section Run-Time Libraries + + +@geindex Tasking and threads libraries + +@geindex Threads libraries and tasking + +@geindex Run-time libraries (platform-specific information) -@noindent The GNAT run-time implementation may vary with respect to both the underlying threads library and the exception handling scheme. For threads support, one or more of the following are supplied: -@itemize @bullet -@item @b{native threads library}, a binding to the thread package from + + +@itemize * + +@item +@strong{native threads library}, a binding to the thread package from the underlying operating system -@item @b{pthreads library} (Sparc Solaris only), a binding to the Solaris +@item +@strong{pthreads library} (Sparc Solaris only), a binding to the Solaris POSIX thread package @end itemize -@noindent For exception handling, either or both of two models are supplied: -@itemize @bullet -@item @b{Zero-Cost Exceptions} (``ZCX''),@footnote{ -Most programs should experience a substantial speed improvement by -being compiled with a ZCX run-time. -This is especially true for -tasking applications or applications with many exception handlers.} -@cindex Zero-Cost Exceptions -@cindex ZCX (Zero-Cost Exceptions) + +@quotation + +@geindex Zero-Cost Exceptions + +@geindex ZCX (Zero-Cost Exceptions) +@end quotation + + +@itemize * + +@item +@strong{Zero-Cost Exceptions} ("ZCX"), which uses binder-generated tables that -are interrogated at run time to locate a handler +are interrogated at run time to locate a handler. + +@geindex setjmp/longjmp Exception Model -@item @b{setjmp / longjmp} (``SJLJ''), -@cindex setjmp/longjmp Exception Model -@cindex SJLJ (setjmp/longjmp Exception Model) +@geindex SJLJ (setjmp/longjmp Exception Model) + +@item +@strong{setjmp / longjmp} ('SJLJ'), which uses dynamically-set data to establish the set of handlers @end itemize -@noindent -This appendix summarizes which combinations of threads and exception support +Most programs should experience a substantial speed improvement by +being compiled with a ZCX run-time. +This is especially true for +tasking applications or applications with many exception handlers.@} + +This section summarizes which combinations of threads and exception support are supplied on various GNAT platforms. It then shows how to select a particular library either permanently or temporarily, @@ -21934,156 +29306,278 @@ libraries, and provides some additional information about several specific platforms. @menu -* Summary of Run-Time Configurations:: -* Specifying a Run-Time Library:: -* Choosing the Scheduling Policy:: -* Solaris-Specific Considerations:: -* Linux-Specific Considerations:: -* AIX-Specific Considerations:: -* RTX-Specific Considerations:: -* HP-UX-Specific Considerations:: +* Summary of Run-Time Configurations:: + @end menu -@node Summary of Run-Time Configurations -@section Summary of Run-Time Configurations - -@multitable @columnfractions .30 .70 -@item @b{alpha-openvms} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native VMS threads -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-sjlj} -@item @code{@ @ @ @ }Tasking @tab native TRU64 threads -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{ia64-hp_linux} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab pthread library -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @b{ia64-hpux} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native HP-UX threads -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{ia64-openvms} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native VMS threads -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @b{ia64-sgi_linux} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab pthread library -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @b{pa-hpux} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native HP-UX threads -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-sjlj} -@item @code{@ @ @ @ }Tasking @tab native HP-UX threads -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{ppc-aix} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native AIX threads -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-sjlj} -@item @code{@ @ @ @ }Tasking @tab native AIX threads -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{ppc-darwin} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native MacOS threads -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @b{sparc-solaris} @tab -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native Solaris threads library -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-pthread} -@item @code{@ @ @ @ }Tasking @tab pthread library -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-sjlj} -@item @code{@ @ @ @ }Tasking @tab native Solaris threads library -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{sparc64-solaris} @tab -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native Solaris threads library -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @b{x86-linux} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab pthread library -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-sjlj} -@item @code{@ @ @ @ }Tasking @tab pthread library -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{x86-lynx} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native LynxOS threads -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{x86-solaris} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native Solaris threads -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-sjlj} -@item @code{@ @ @ @ }Tasking @tab native Solaris threads library -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{x86-windows} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab native Win32 threads -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-sjlj} -@item @code{@ @ @ @ }Tasking @tab native Win32 threads -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @b{x86-windows-rtx} -@item @code{@ @ }@i{rts-rtx-rtss (default)} -@item @code{@ @ @ @ }Tasking @tab RTX real-time subsystem RTSS threads (kernel mode) -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* -@item @code{@ @ }@i{rts-rtx-w32} -@item @code{@ @ @ @ }Tasking @tab RTX Win32 threads (user mode) -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @b{x86_64-linux} -@item @code{@ @ }@i{rts-native (default)} -@item @code{@ @ @ @ }Tasking @tab pthread library -@item @code{@ @ @ @ }Exceptions @tab ZCX -@* -@item @code{@ @ }@i{rts-sjlj} -@item @code{@ @ @ @ }Tasking @tab pthread library -@item @code{@ @ @ @ }Exceptions @tab SJLJ -@* +@node Summary of Run-Time Configurations,,,Run-Time Libraries +@anchor{gnat_ugn/platform_specific_information summary-of-run-time-configurations}@anchor{25b}@anchor{gnat_ugn/platform_specific_information id3}@anchor{25c} +@subsection Summary of Run-Time Configurations + + + +@multitable {xxxxxxxxxxxxxxxxxxx} {xxxxxxxxxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxx} {xxxxxxxxxxxxxx} +@headitem + +Platform + +@tab + +Run-Time + +@tab + +Tasking + +@tab + +Exceptions + +@item + +ppc-aix + +@tab + +rts-native +(default) + +@tab + +native AIX threads + +@tab + +ZCX + +@item + +rts-sjlj + +@tab + +native AIX threads + +@tab + +SJLJ + +@item + +sparc-solaris + +@tab + +rts-native +(default) + +@tab + +native Solaris +threads library + +@tab + +ZCX + +@item + +rts-pthread + +@tab + +pthread library + +@tab + +ZCX + +@item + +rts-sjlj + +@tab + +native Solaris +threads library + +@tab + +SJLJ + +@item + +sparc64-solaris + +@tab + +rts-native +(default) + +@tab + +native Solaris +threads library + +@tab + +ZCX + +@item + +x86-linux + +@tab + +rts-native +(default) + +@tab + +pthread library + +@tab + +ZCX + +@item + +rts-sjlj + +@tab + +pthread library + +@tab + +SJLJ + +@item + +x86-lynx + +@tab + +rts-native +(default) + +@tab + +native LynxOS threads + +@tab + +SJLJ + +@item + +x86-solaris + +@tab + +rts-native +(default) + +@tab + +native Solaris +threads library + +@tab + +ZCX + +@item + +rts-sjlj + +@tab + +native Solaris +threads library + +@tab + +SJLJ + +@item + +x86-windows + +@tab + +rts-native +(default) + +@tab + +native Win32 threads + +@tab + +ZCX + +@item + +rts-sjlj + +@tab + +native Win32 threads + +@tab + +SJLJ + +@item + +x86_64-linux + +@tab + +rts-native +(default) + +@tab + +pthread library + +@tab + +ZCX + +@item + +rts-sjlj + +@tab + +pthread library + +@tab + +SJLJ + @end multitable -@node Specifying a Run-Time Library + +@node Specifying a Run-Time Library,Microsoft Windows Topics,Run-Time Libraries,Platform-Specific Information +@anchor{gnat_ugn/platform_specific_information specifying-a-run-time-library}@anchor{25d}@anchor{gnat_ugn/platform_specific_information id4}@anchor{25e} @section Specifying a Run-Time Library -@noindent -The @file{adainclude} subdirectory containing the sources of the GNAT -run-time library, and the @file{adalib} subdirectory containing the -@file{ALI} files and the static and/or shared GNAT library, are located + +The @code{adainclude} subdirectory containing the sources of the GNAT +run-time library, and the @code{adalib} subdirectory containing the +@code{ALI} files and the static and/or shared GNAT library, are located in the gcc target-dependent area: -@smallexample -target=$prefix/lib/gcc/gcc-@i{dumpmachine}/gcc-@i{dumpversion}/ -@end smallexample +@quotation + +@example +target=$prefix/lib/gcc/gcc-*dumpmachine*/gcc-*dumpversion*/ +@end example +@end quotation -@noindent As indicated above, on some platforms several run-time libraries are supplied. These libraries are installed in the target dependent area and contain a complete source and binary subdirectory. The detailed description @@ -22094,121 +29588,148 @@ The default run-time library (when GNAT is installed) is @emph{rts-native}. This default run time is selected by the means of soft links. For example on x86-linux: -@smallexample -@group - $(target-dir) - | - +--- adainclude----------+ - | | - +--- adalib-----------+ | - | | | - +--- rts-native | | - | | | | - | +--- adainclude <---+ - | | | - | +--- adalib <----+ - | - +--- rts-sjlj - | - +--- adainclude - | - +--- adalib -@end group -@end smallexample - -@noindent -If the @i{rts-sjlj} library is to be selected on a permanent basis, +@quotation + +@image{rtlibrary-structure,,,,png} +@end quotation + +@c -- +@c -- $(target-dir) +@c -- | +@c -- +--- adainclude----------+ +@c -- | | +@c -- +--- adalib-----------+ | +@c -- | | | +@c -- +--- rts-native | | +@c -- | | | | +@c -- | +--- adainclude <---+ +@c -- | | | +@c -- | +--- adalib <----+ +@c -- | +@c -- +--- rts-sjlj +@c -- | +@c -- +--- adainclude +@c -- | +@c -- +--- adalib + +If the @emph{rts-sjlj} library is to be selected on a permanent basis, these soft links can be modified with the following commands: -@smallexample +@quotation + +@example $ cd $target $ rm -f adainclude adalib $ ln -s rts-sjlj/adainclude adainclude $ ln -s rts-sjlj/adalib adalib -@end smallexample +@end example +@end quotation + +Alternatively, you can specify @code{rts-sjlj/adainclude} in the file +@code{$target/ada_source_path} and @code{rts-sjlj/adalib} in +@code{$target/ada_object_path}. -@noindent -Alternatively, you can specify @file{rts-sjlj/adainclude} in the file -@file{$target/ada_source_path} and @file{rts-sjlj/adalib} in -@file{$target/ada_object_path}. +@geindex --RTS option Selecting another run-time library temporarily can be -achieved by using the @option{--RTS} switch, e.g., @option{--RTS=sjlj} -@cindex @option{--RTS} option +achieved by using the @emph{--RTS} switch, e.g., @emph{--RTS=sjlj} +@anchor{gnat_ugn/platform_specific_information choosing-the-scheduling-policy}@anchor{25f} +@geindex SCHED_FIFO scheduling policy + +@geindex SCHED_RR scheduling policy + +@geindex SCHED_OTHER scheduling policy + +@menu +* Choosing the Scheduling Policy:: +* Solaris-Specific Considerations:: +* Solaris Threads Issues:: +* AIX-Specific Considerations:: + +@end menu + +@node Choosing the Scheduling Policy,Solaris-Specific Considerations,,Specifying a Run-Time Library +@anchor{gnat_ugn/platform_specific_information id5}@anchor{260} +@subsection Choosing the Scheduling Policy -@node Choosing the Scheduling Policy -@section Choosing the Scheduling Policy -@noindent When using a POSIX threads implementation, you have a choice of several -scheduling policies: @code{SCHED_FIFO}, -@cindex @code{SCHED_FIFO} scheduling policy -@code{SCHED_RR} -@cindex @code{SCHED_RR} scheduling policy -and @code{SCHED_OTHER}. -@cindex @code{SCHED_OTHER} scheduling policy -Typically, the default is @code{SCHED_OTHER}, while using @code{SCHED_FIFO} -or @code{SCHED_RR} requires special (e.g., root) privileges. - -By default, GNAT uses the @code{SCHED_OTHER} policy. To specify -@code{SCHED_FIFO}, -@cindex @code{SCHED_FIFO} scheduling policy +scheduling policies: @cite{SCHED_FIFO}, @cite{SCHED_RR} and @cite{SCHED_OTHER}. + +Typically, the default is @cite{SCHED_OTHER}, while using @cite{SCHED_FIFO} +or @cite{SCHED_RR} requires special (e.g., root) privileges. + +@geindex pragma Time_Slice + +@geindex -T0 option + +@geindex pragma Task_Dispatching_Policy + +By default, GNAT uses the @cite{SCHED_OTHER} policy. To specify +@cite{SCHED_FIFO}, you can use one of the following: -@itemize @bullet -@item -@code{pragma Time_Slice (0.0)} -@cindex pragma Time_Slice -@item -the corresponding binder option @option{-T0} -@cindex @option{-T0} option -@item -@code{pragma Task_Dispatching_Policy (FIFO_Within_Priorities)} -@cindex pragma Task_Dispatching_Policy + +@itemize * + +@item +@cite{pragma Time_Slice (0.0)} + +@item +the corresponding binder option @emph{-T0} + +@item +@cite{pragma Task_Dispatching_Policy (FIFO_Within_Priorities)} @end itemize -@noindent -To specify @code{SCHED_RR}, -@cindex @code{SCHED_RR} scheduling policy -you should use @code{pragma Time_Slice} with a -value greater than @code{0.0}, or else use the corresponding @option{-T} +To specify @cite{SCHED_RR}, +you should use @cite{pragma Time_Slice} with a +value greater than 0.0, or else use the corresponding @emph{-T} binder option. -@node Solaris-Specific Considerations -@section Solaris-Specific Considerations -@cindex Solaris Sparc threads libraries +@geindex Solaris Sparc threads libraries + +@node Solaris-Specific Considerations,Solaris Threads Issues,Choosing the Scheduling Policy,Specifying a Run-Time Library +@anchor{gnat_ugn/platform_specific_information id6}@anchor{261}@anchor{gnat_ugn/platform_specific_information solaris-specific-considerations}@anchor{262} +@subsection Solaris-Specific Considerations + -@noindent This section addresses some topics related to the various threads libraries on Sparc Solaris. -@menu -* Solaris Threads Issues:: -@end menu +@geindex rts-pthread threads library -@node Solaris Threads Issues +@node Solaris Threads Issues,AIX-Specific Considerations,Solaris-Specific Considerations,Specifying a Run-Time Library +@anchor{gnat_ugn/platform_specific_information id7}@anchor{263}@anchor{gnat_ugn/platform_specific_information solaris-threads-issues}@anchor{264} @subsection Solaris Threads Issues -@noindent + GNAT under Solaris/Sparc 32 bits comes with an alternate tasking run-time library based on POSIX threads --- @emph{rts-pthread}. -@cindex rts-pthread threads library + +@geindex PTHREAD_PRIO_INHERIT policy (under rts-pthread) + +@geindex PTHREAD_PRIO_PROTECT policy (under rts-pthread) + +@geindex pragma Locking_Policy (under rts-pthread) + +@geindex Inheritance_Locking (under rts-pthread) + +@geindex Ceiling_Locking (under rts-pthread) + This run-time library has the advantage of being mostly shared across all POSIX-compliant thread implementations, and it also provides under -@w{Solaris 8} the @code{PTHREAD_PRIO_INHERIT} -@cindex @code{PTHREAD_PRIO_INHERIT} policy (under rts-pthread) -and @code{PTHREAD_PRIO_PROTECT} -@cindex @code{PTHREAD_PRIO_PROTECT} policy (under rts-pthread) +Solaris 8 the @cite{PTHREAD_PRIO_INHERIT} +and @cite{PTHREAD_PRIO_PROTECT} semantics that can be selected using the predefined pragma -@code{Locking_Policy} -@cindex pragma Locking_Policy (under rts-pthread) +@cite{Locking_Policy} with respectively -@code{Inheritance_Locking} and @code{Ceiling_Locking} as the policy. -@cindex @code{Inheritance_Locking} (under rts-pthread) -@cindex @code{Ceiling_Locking} (under rts-pthread) +@cite{Inheritance_Locking} and @cite{Ceiling_Locking} as the policy. As explained above, the native run-time library is based on the Solaris thread -library (@code{libthread}) and is the default library. +library (@cite{libthread}) and is the default library. + +@geindex GNAT_PROCESSOR environment variable (on Sparc Solaris) When the Solaris threads library is used (this is the default), programs compiled with GNAT can automatically take advantage of @@ -22216,133 +29737,2347 @@ and can thus execute on multiple processors. The user can alternatively specify a processor on which the program should run to emulate a single-processor system. The multiprocessor / uniprocessor choice is made by -setting the environment variable @env{GNAT_PROCESSOR} -@cindex @env{GNAT_PROCESSOR} environment variable (on Sparc Solaris) +setting the environment variable +@geindex GNAT_PROCESSOR +@geindex environment variable; GNAT_PROCESSOR +@code{GNAT_PROCESSOR} to one of the following: -@table @code -@item -2 +@quotation + + +@multitable {xxxxxxxxxxxxxxxxxxxxxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@headitem + +@code{GNAT_PROCESSOR} Value + +@tab + +Effect + +@item + +@emph{-2} + +@tab + Use the default configuration (run the program on all -available processors) - this is the same as having @code{GNAT_PROCESSOR} +available processors) - this is the same as having @cite{GNAT_PROCESSOR} unset -@item -1 -Let the run-time implementation choose one processor and run the program on -that processor +@item + +@emph{-1} + +@tab + +Let the run-time implementation choose one processor and run the +program on that processor + +@item + +@emph{0 .. Last_Proc} + +@tab -@item 0 .. Last_Proc Run the program on the specified processor. -@code{Last_Proc} is equal to @code{_SC_NPROCESSORS_CONF - 1} -(where @code{_SC_NPROCESSORS_CONF} is a system variable). -@end table +@cite{Last_Proc} is equal to @cite{_SC_NPROCESSORS_CONF - 1} +(where @cite{_SC_NPROCESSORS_CONF} is a system variable). -@node Linux-Specific Considerations -@section Linux-Specific Considerations -@cindex Linux threads libraries +@end multitable + +@end quotation + +@node AIX-Specific Considerations,,Solaris Threads Issues,Specifying a Run-Time Library +@anchor{gnat_ugn/platform_specific_information aix-specific-considerations}@anchor{265}@anchor{gnat_ugn/platform_specific_information id8}@anchor{266} +@subsection AIX-Specific Considerations -@noindent -On GNU/Linux without NPTL support (usually system with GNU C Library -older than 2.3), the signal model is not POSIX compliant, which means -that to send a signal to the process, you need to send the signal to all -threads, e.g.@: by using @code{killpg()}. -@node AIX-Specific Considerations -@section AIX-Specific Considerations -@cindex AIX resolver library +@geindex AIX resolver library -@noindent On AIX, the resolver library initializes some internal structure on -the first call to @code{get*by*} functions, which are used to implement -@code{GNAT.Sockets.Get_Host_By_Name} and -@code{GNAT.Sockets.Get_Host_By_Address}. +the first call to @cite{get*by*} functions, which are used to implement +@cite{GNAT.Sockets.Get_Host_By_Name} and +@cite{GNAT.Sockets.Get_Host_By_Address}. If such initialization occurs within an Ada task, and the stack size for the task is the default size, a stack overflow may occur. To avoid this overflow, the user should either ensure that the first call -to @code{GNAT.Sockets.Get_Host_By_Name} or -@code{GNAT.Sockets.Get_Host_By_Addrss} -occurs in the environment task, or use @code{pragma Storage_Size} to +to @cite{GNAT.Sockets.Get_Host_By_Name} or +@cite{GNAT.Sockets.Get_Host_By_Addrss} +occurs in the environment task, or use @cite{pragma Storage_Size} to specify a sufficiently large size for the stack of the task that contains this call. -@node RTX-Specific Considerations -@section RTX-Specific Considerations -@cindex RTX libraries +@geindex Windows NT + +@geindex Windows 95 + +@geindex Windows 98 + +@node Microsoft Windows Topics,Mac OS Topics,Specifying a Run-Time Library,Platform-Specific Information +@anchor{gnat_ugn/platform_specific_information microsoft-windows-topics}@anchor{2e}@anchor{gnat_ugn/platform_specific_information id9}@anchor{267} +@section Microsoft Windows Topics + + +This section describes topics that are specific to the Microsoft Windows +platforms. -@noindent -The Real-time Extension (RTX) to Windows is based on the Windows Win32 -API. Applications can be built to work in two different modes: -@itemize @bullet -@item -Windows executables that run in Ring 3 to utilize memory protection -(@emph{rts-rtx-w32}). -@item -Real-time subsystem (RTSS) executables that run in Ring 0, where -performance can be optimized with RTSS applications taking precedent -over all Windows applications (@emph{rts-rtx-rtss}). This mode requires -the Microsoft linker to handle RTSS libraries. + +@menu +* Using GNAT on Windows:: +* Using a network installation of GNAT:: +* CONSOLE and WINDOWS subsystems:: +* Temporary Files:: +* Mixed-Language Programming on Windows:: + +@end menu + +@node Using GNAT on Windows,Using a network installation of GNAT,,Microsoft Windows Topics +@anchor{gnat_ugn/platform_specific_information using-gnat-on-windows}@anchor{268}@anchor{gnat_ugn/platform_specific_information id10}@anchor{269} +@subsection Using GNAT on Windows + + +One of the strengths of the GNAT technology is that its tool set +(@emph{gcc}, @emph{gnatbind}, @emph{gnatlink}, @emph{gnatmake}, the +@cite{gdb} debugger, etc.) is used in the same way regardless of the +platform. + +On Windows this tool set is complemented by a number of Microsoft-specific +tools that have been provided to facilitate interoperability with Windows +when this is required. With these tools: + + +@itemize * + +@item +You can build applications using the @cite{CONSOLE} or @cite{WINDOWS} +subsystems. + +@item +You can use any Dynamically Linked Library (DLL) in your Ada code (both +relocatable and non-relocatable DLLs are supported). + +@item +You can build Ada DLLs for use in other applications. These applications +can be written in a language other than Ada (e.g., C, C++, etc). Again both +relocatable and non-relocatable Ada DLLs are supported. + +@item +You can include Windows resources in your Ada application. + +@item +You can use or create COM/DCOM objects. @end itemize -@node HP-UX-Specific Considerations -@section HP-UX-Specific Considerations -@cindex HP-UX Scheduling +Immediately below are listed all known general GNAT-for-Windows restrictions. +Other restrictions about specific features like Windows Resources and DLLs +are listed in separate sections below. -@noindent -On HP-UX, appropriate privileges are required to change the scheduling -parameters of a task. The calling process must have appropriate -privileges or be a member of a group having @code{PRIV_RTSCHED} access to -successfully change the scheduling parameters. -By default, GNAT uses the @code{SCHED_HPUX} policy. To have access to the -priority range 0-31 either the @code{FIFO_Within_Priorities} or the -@code{Round_Robin_Within_Priorities} scheduling policies need to be set. +@itemize * -To specify the @code{FIFO_Within_Priorities} scheduling policy you can use -one of the following: +@item +It is not possible to use @cite{GetLastError} and @cite{SetLastError} +when tasking, protected records, or exceptions are used. In these +cases, in order to implement Ada semantics, the GNAT run-time system +calls certain Win32 routines that set the last error variable to 0 upon +success. It should be possible to use @cite{GetLastError} and +@cite{SetLastError} when tasking, protected record, and exception +features are not used, but it is not guaranteed to work. -@itemize @bullet -@item -@code{pragma Time_Slice (0.0)} -@cindex pragma Time_Slice -@item -the corresponding binder option @option{-T0} -@cindex @option{-T0} option -@item -@code{pragma Task_Dispatching_Policy (FIFO_Within_Priorities)} -@cindex pragma Task_Dispatching_Policy +@item +It is not possible to link against Microsoft C++ libraries except for +import libraries. Interfacing must be done by the mean of DLLs. + +@item +It is possible to link against Microsoft C libraries. Yet the preferred +solution is to use C/C++ compiler that comes with GNAT, since it +doesn't require having two different development environments and makes the +inter-language debugging experience smoother. + +@item +When the compilation environment is located on FAT32 drives, users may +experience recompilations of the source files that have not changed if +Daylight Saving Time (DST) state has changed since the last time files +were compiled. NTFS drives do not have this problem. + +@item +No components of the GNAT toolset use any entries in the Windows +registry. The only entries that can be created are file associations and +PATH settings, provided the user has chosen to create them at installation +time, as well as some minimal book-keeping information needed to correctly +uninstall or integrate different GNAT products. +@end itemize + +@node Using a network installation of GNAT,CONSOLE and WINDOWS subsystems,Using GNAT on Windows,Microsoft Windows Topics +@anchor{gnat_ugn/platform_specific_information id11}@anchor{26a}@anchor{gnat_ugn/platform_specific_information using-a-network-installation-of-gnat}@anchor{26b} +@subsection Using a network installation of GNAT + + +Make sure the system on which GNAT is installed is accessible from the +current machine, i.e., the install location is shared over the network. +Shared resources are accessed on Windows by means of UNC paths, which +have the format @cite{\\server\sharename\path} + +In order to use such a network installation, simply add the UNC path of the +@code{bin} directory of your GNAT installation in front of your PATH. For +example, if GNAT is installed in @code{\GNAT} directory of a share location +called @code{c-drive} on a machine @code{LOKI}, the following command will +make it available: + +@quotation + +@example +$ path \\loki\c-drive\gnat\bin;%path%` +@end example +@end quotation + +Be aware that every compilation using the network installation results in the +transfer of large amounts of data across the network and will likely cause +serious performance penalty. + +@node CONSOLE and WINDOWS subsystems,Temporary Files,Using a network installation of GNAT,Microsoft Windows Topics +@anchor{gnat_ugn/platform_specific_information id12}@anchor{26c}@anchor{gnat_ugn/platform_specific_information console-and-windows-subsystems}@anchor{26d} +@subsection CONSOLE and WINDOWS subsystems + + +@geindex CONSOLE Subsystem + +@geindex WINDOWS Subsystem + +@geindex -mwindows + +There are two main subsystems under Windows. The @cite{CONSOLE} subsystem +(which is the default subsystem) will always create a console when +launching the application. This is not something desirable when the +application has a Windows GUI. To get rid of this console the +application must be using the @cite{WINDOWS} subsystem. To do so +the @emph{-mwindows} linker option must be specified. + +@quotation + +@example +$ gnatmake winprog -largs -mwindows +@end example +@end quotation + +@node Temporary Files,Mixed-Language Programming on Windows,CONSOLE and WINDOWS subsystems,Microsoft Windows Topics +@anchor{gnat_ugn/platform_specific_information id13}@anchor{26e}@anchor{gnat_ugn/platform_specific_information temporary-files}@anchor{26f} +@subsection Temporary Files + + +@geindex Temporary files + +It is possible to control where temporary files gets created by setting +the +@geindex TMP +@geindex environment variable; TMP +@code{TMP} environment variable. The file will be created: + + +@itemize * + +@item +Under the directory pointed to by the +@geindex TMP +@geindex environment variable; TMP +@code{TMP} environment variable if +this directory exists. + +@item +Under @code{c:\temp}, if the +@geindex TMP +@geindex environment variable; TMP +@code{TMP} environment variable is not +set (or not pointing to a directory) and if this directory exists. + +@item +Under the current working directory otherwise. +@end itemize + +This allows you to determine exactly where the temporary +file will be created. This is particularly useful in networked +environments where you may not have write access to some +directories. + +@node Mixed-Language Programming on Windows,,Temporary Files,Microsoft Windows Topics +@anchor{gnat_ugn/platform_specific_information mixed-language-programming-on-windows}@anchor{270}@anchor{gnat_ugn/platform_specific_information id14}@anchor{271} +@subsection Mixed-Language Programming on Windows + + +Developing pure Ada applications on Windows is no different than on +other GNAT-supported platforms. However, when developing or porting an +application that contains a mix of Ada and C/C++, the choice of your +Windows C/C++ development environment conditions your overall +interoperability strategy. + +If you use @emph{gcc} or Microsoft C to compile the non-Ada part of +your application, there are no Windows-specific restrictions that +affect the overall interoperability with your Ada code. If you do want +to use the Microsoft tools for your C++ code, you have two choices: + + +@itemize * + +@item +Encapsulate your C++ code in a DLL to be linked with your Ada +application. In this case, use the Microsoft or whatever environment to +build the DLL and use GNAT to build your executable +(@ref{272,,Using DLLs with GNAT}). + +@item +Or you can encapsulate your Ada code in a DLL to be linked with the +other part of your application. In this case, use GNAT to build the DLL +(@ref{273,,Building DLLs with GNAT Project files}) and use the Microsoft +or whatever environment to build your executable. +@end itemize + +In addition to the description about C main in +@ref{46,,Mixed Language Programming} section, if the C main uses a +stand-alone library it is required on x86-windows to +setup the SEH context. For this the C main must looks like this: + +@quotation + +@example +/* main.c */ +extern void adainit (void); +extern void adafinal (void); +extern void __gnat_initialize(void*); +extern void call_to_ada (void); + +int main (int argc, char *argv[]) +@{ + int SEH [2]; + + /* Initialize the SEH context */ + __gnat_initialize (&SEH); + + adainit(); + + /* Then call Ada services in the stand-alone library */ + + call_to_ada(); + + adafinal(); +@} +@end example +@end quotation + +Note that this is not needed on x86_64-windows where the Windows +native SEH support is used. + +@menu +* Windows Calling Conventions:: +* Introduction to Dynamic Link Libraries (DLLs): Introduction to Dynamic Link Libraries DLLs. +* Using DLLs with GNAT:: +* Building DLLs with GNAT Project files:: +* Building DLLs with GNAT:: +* Building DLLs with gnatdll:: +* Ada DLLs and Finalization:: +* Creating a Spec for Ada DLLs:: +* GNAT and Windows Resources:: +* Debugging a DLL:: +* Setting Stack Size from gnatlink:: +* Setting Heap Size from gnatlink:: + +@end menu + +@node Windows Calling Conventions,Introduction to Dynamic Link Libraries DLLs,,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information windows-calling-conventions}@anchor{274}@anchor{gnat_ugn/platform_specific_information id15}@anchor{275} +@subsubsection Windows Calling Conventions + + +@geindex Stdcall + +@geindex APIENTRY + +This section pertain only to Win32. On Win64 there is a single native +calling convention. All convention specifiers are ignored on this +platform. + +When a subprogram @cite{F} (caller) calls a subprogram @cite{G} +(callee), there are several ways to push @cite{G}'s parameters on the +stack and there are several possible scenarios to clean up the stack +upon @cite{G}'s return. A calling convention is an agreed upon software +protocol whereby the responsibilities between the caller (@cite{F}) and +the callee (@cite{G}) are clearly defined. Several calling conventions +are available for Windows: + + +@itemize * + +@item +@cite{C} (Microsoft defined) + +@item +@cite{Stdcall} (Microsoft defined) + +@item +@cite{Win32} (GNAT specific) + +@item +@cite{DLL} (GNAT specific) +@end itemize + +@menu +* C Calling Convention:: +* Stdcall Calling Convention:: +* Win32 Calling Convention:: +* DLL Calling Convention:: + +@end menu + +@node C Calling Convention,Stdcall Calling Convention,,Windows Calling Conventions +@anchor{gnat_ugn/platform_specific_information c-calling-convention}@anchor{276}@anchor{gnat_ugn/platform_specific_information id16}@anchor{277} +@subsubsection @cite{C} Calling Convention + + +This is the default calling convention used when interfacing to C/C++ +routines compiled with either @emph{gcc} or Microsoft Visual C++. + +In the @cite{C} calling convention subprogram parameters are pushed on the +stack by the caller from right to left. The caller itself is in charge of +cleaning up the stack after the call. In addition, the name of a routine +with @cite{C} calling convention is mangled by adding a leading underscore. + +The name to use on the Ada side when importing (or exporting) a routine +with @cite{C} calling convention is the name of the routine. For +instance the C function: + +@quotation + +@example +int get_val (long); +@end example +@end quotation + +should be imported from Ada as follows: + +@quotation + +@example +function Get_Val (V : Interfaces.C.long) return Interfaces.C.int; +pragma Import (C, Get_Val, External_Name => "get_val"); +@end example +@end quotation + +Note that in this particular case the @cite{External_Name} parameter could +have been omitted since, when missing, this parameter is taken to be the +name of the Ada entity in lower case. When the @cite{Link_Name} parameter +is missing, as in the above example, this parameter is set to be the +@cite{External_Name} with a leading underscore. + +When importing a variable defined in C, you should always use the @cite{C} +calling convention unless the object containing the variable is part of a +DLL (in which case you should use the @cite{Stdcall} calling +convention, @ref{278,,Stdcall Calling Convention}). + +@node Stdcall Calling Convention,Win32 Calling Convention,C Calling Convention,Windows Calling Conventions +@anchor{gnat_ugn/platform_specific_information stdcall-calling-convention}@anchor{278}@anchor{gnat_ugn/platform_specific_information id17}@anchor{279} +@subsubsection @cite{Stdcall} Calling Convention + + +This convention, which was the calling convention used for Pascal +programs, is used by Microsoft for all the routines in the Win32 API for +efficiency reasons. It must be used to import any routine for which this +convention was specified. + +In the @cite{Stdcall} calling convention subprogram parameters are pushed +on the stack by the caller from right to left. The callee (and not the +caller) is in charge of cleaning the stack on routine exit. In addition, +the name of a routine with @cite{Stdcall} calling convention is mangled by +adding a leading underscore (as for the @cite{C} calling convention) and a +trailing @code{@@@emph{nn}}, where @cite{nn} is the overall size (in +bytes) of the parameters passed to the routine. + +The name to use on the Ada side when importing a C routine with a +@cite{Stdcall} calling convention is the name of the C routine. The leading +underscore and trailing @code{@@@emph{nn}} are added automatically by +the compiler. For instance the Win32 function: + +@quotation + +@example +APIENTRY int get_val (long); +@end example +@end quotation + +should be imported from Ada as follows: + +@quotation + +@example +function Get_Val (V : Interfaces.C.long) return Interfaces.C.int; +pragma Import (Stdcall, Get_Val); +-- On the x86 a long is 4 bytes, so the Link_Name is "_get_val@@4" +@end example +@end quotation + +As for the @cite{C} calling convention, when the @cite{External_Name} +parameter is missing, it is taken to be the name of the Ada entity in lower +case. If instead of writing the above import pragma you write: + +@quotation + +@example +function Get_Val (V : Interfaces.C.long) return Interfaces.C.int; +pragma Import (Stdcall, Get_Val, External_Name => "retrieve_val"); +@end example +@end quotation + +then the imported routine is @cite{_retrieve_val@@4}. However, if instead +of specifying the @cite{External_Name} parameter you specify the +@cite{Link_Name} as in the following example: + +@quotation + +@example +function Get_Val (V : Interfaces.C.long) return Interfaces.C.int; +pragma Import (Stdcall, Get_Val, Link_Name => "retrieve_val"); +@end example +@end quotation + +then the imported routine is @cite{retrieve_val}, that is, there is no +decoration at all. No leading underscore and no Stdcall suffix +@code{@@@emph{nn}}. + +This is especially important as in some special cases a DLL's entry +point name lacks a trailing @code{@@@emph{nn}} while the exported +name generated for a call has it. + +It is also possible to import variables defined in a DLL by using an +import pragma for a variable. As an example, if a DLL contains a +variable defined as: + +@quotation + +@example +int my_var; +@end example +@end quotation + +then, to access this variable from Ada you should write: + +@quotation + +@example +My_Var : Interfaces.C.int; +pragma Import (Stdcall, My_Var); +@end example +@end quotation + +Note that to ease building cross-platform bindings this convention +will be handled as a @cite{C} calling convention on non-Windows platforms. + +@node Win32 Calling Convention,DLL Calling Convention,Stdcall Calling Convention,Windows Calling Conventions +@anchor{gnat_ugn/platform_specific_information id18}@anchor{27a}@anchor{gnat_ugn/platform_specific_information win32-calling-convention}@anchor{27b} +@subsubsection @cite{Win32} Calling Convention + + +This convention, which is GNAT-specific is fully equivalent to the +@cite{Stdcall} calling convention described above. + +@node DLL Calling Convention,,Win32 Calling Convention,Windows Calling Conventions +@anchor{gnat_ugn/platform_specific_information id19}@anchor{27c}@anchor{gnat_ugn/platform_specific_information dll-calling-convention}@anchor{27d} +@subsubsection @cite{DLL} Calling Convention + + +This convention, which is GNAT-specific is fully equivalent to the +@cite{Stdcall} calling convention described above. + +@node Introduction to Dynamic Link Libraries DLLs,Using DLLs with GNAT,Windows Calling Conventions,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information id20}@anchor{27e}@anchor{gnat_ugn/platform_specific_information introduction-to-dynamic-link-libraries-dlls}@anchor{27f} +@subsubsection Introduction to Dynamic Link Libraries (DLLs) + + +@geindex DLL + +A Dynamically Linked Library (DLL) is a library that can be shared by +several applications running under Windows. A DLL can contain any number of +routines and variables. + +One advantage of DLLs is that you can change and enhance them without +forcing all the applications that depend on them to be relinked or +recompiled. However, you should be aware than all calls to DLL routines are +slower since, as you will understand below, such calls are indirect. + +To illustrate the remainder of this section, suppose that an application +wants to use the services of a DLL @code{API.dll}. To use the services +provided by @code{API.dll} you must statically link against the DLL or +an import library which contains a jump table with an entry for each +routine and variable exported by the DLL. In the Microsoft world this +import library is called @code{API.lib}. When using GNAT this import +library is called either @code{libAPI.dll.a}, @code{libapi.dll.a}, +@code{libAPI.a} or @code{libapi.a} (names are case insensitive). + +After you have linked your application with the DLL or the import library +and you run your application, here is what happens: + + +@itemize * + +@item +Your application is loaded into memory. + +@item +The DLL @code{API.dll} is mapped into the address space of your +application. This means that: + + +@itemize - + +@item +The DLL will use the stack of the calling thread. + +@item +The DLL will use the virtual address space of the calling process. + +@item +The DLL will allocate memory from the virtual address space of the calling +process. + +@item +Handles (pointers) can be safely exchanged between routines in the DLL +routines and routines in the application using the DLL. +@end itemize + +@item +The entries in the jump table (from the import library @code{libAPI.dll.a} +or @code{API.lib} or automatically created when linking against a DLL) +which is part of your application are initialized with the addresses +of the routines and variables in @code{API.dll}. + +@item +If present in @code{API.dll}, routines @cite{DllMain} or +@cite{DllMainCRTStartup} are invoked. These routines typically contain +the initialization code needed for the well-being of the routines and +variables exported by the DLL. +@end itemize + +There is an additional point which is worth mentioning. In the Windows +world there are two kind of DLLs: relocatable and non-relocatable +DLLs. Non-relocatable DLLs can only be loaded at a very specific address +in the target application address space. If the addresses of two +non-relocatable DLLs overlap and these happen to be used by the same +application, a conflict will occur and the application will run +incorrectly. Hence, when possible, it is always preferable to use and +build relocatable DLLs. Both relocatable and non-relocatable DLLs are +supported by GNAT. Note that the @emph{-s} linker option (see GNU Linker +User's Guide) removes the debugging symbols from the DLL but the DLL can +still be relocated. + +As a side note, an interesting difference between Microsoft DLLs and +Unix shared libraries, is the fact that on most Unix systems all public +routines are exported by default in a Unix shared library, while under +Windows it is possible (but not required) to list exported routines in +a definition file (see @ref{280,,The Definition File}). + +@node Using DLLs with GNAT,Building DLLs with GNAT Project files,Introduction to Dynamic Link Libraries DLLs,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information id21}@anchor{281}@anchor{gnat_ugn/platform_specific_information using-dlls-with-gnat}@anchor{272} +@subsubsection Using DLLs with GNAT + + +To use the services of a DLL, say @code{API.dll}, in your Ada application +you must have: + + +@itemize * + +@item +The Ada spec for the routines and/or variables you want to access in +@code{API.dll}. If not available this Ada spec must be built from the C/C++ +header files provided with the DLL. + +@item +The import library (@code{libAPI.dll.a} or @code{API.lib}). As previously +mentioned an import library is a statically linked library containing the +import table which will be filled at load time to point to the actual +@code{API.dll} routines. Sometimes you don't have an import library for the +DLL you want to use. The following sections will explain how to build +one. Note that this is optional. + +@item +The actual DLL, @code{API.dll}. +@end itemize + +Once you have all the above, to compile an Ada application that uses the +services of @code{API.dll} and whose main subprogram is @cite{My_Ada_App}, +you simply issue the command + +@quotation + +@example +$ gnatmake my_ada_app -largs -lAPI +@end example +@end quotation + +The argument @emph{-largs -lAPI} at the end of the @emph{gnatmake} command +tells the GNAT linker to look for an import library. The linker will +look for a library name in this specific order: + + +@itemize * + +@item +@code{libAPI.dll.a} + +@item +@code{API.dll.a} + +@item +@code{libAPI.a} + +@item +@code{API.lib} + +@item +@code{libAPI.dll} + +@item +@code{API.dll} +@end itemize + +The first three are the GNU style import libraries. The third is the +Microsoft style import libraries. The last two are the actual DLL names. + +Note that if the Ada package spec for @code{API.dll} contains the +following pragma + +@quotation + +@example +pragma Linker_Options ("-lAPI"); +@end example +@end quotation + +you do not have to add @emph{-largs -lAPI} at the end of the +@emph{gnatmake} command. + +If any one of the items above is missing you will have to create it +yourself. The following sections explain how to do so using as an +example a fictitious DLL called @code{API.dll}. + +@menu +* Creating an Ada Spec for the DLL Services:: +* Creating an Import Library:: + +@end menu + +@node Creating an Ada Spec for the DLL Services,Creating an Import Library,,Using DLLs with GNAT +@anchor{gnat_ugn/platform_specific_information creating-an-ada-spec-for-the-dll-services}@anchor{282}@anchor{gnat_ugn/platform_specific_information id22}@anchor{283} +@subsubsection Creating an Ada Spec for the DLL Services + + +A DLL typically comes with a C/C++ header file which provides the +definitions of the routines and variables exported by the DLL. The Ada +equivalent of this header file is a package spec that contains definitions +for the imported entities. If the DLL you intend to use does not come with +an Ada spec you have to generate one such spec yourself. For example if +the header file of @code{API.dll} is a file @code{api.h} containing the +following two definitions: + +@quotation + +@example +int some_var; +int get (char *); +@end example +@end quotation + +then the equivalent Ada spec could be: + +@quotation + +@example +with Interfaces.C.Strings; +package API is + use Interfaces; + + Some_Var : C.int; + function Get (Str : C.Strings.Chars_Ptr) return C.int; + +private + pragma Import (C, Get); + pragma Import (DLL, Some_Var); +end API; +@end example +@end quotation + +@node Creating an Import Library,,Creating an Ada Spec for the DLL Services,Using DLLs with GNAT +@anchor{gnat_ugn/platform_specific_information id23}@anchor{284}@anchor{gnat_ugn/platform_specific_information creating-an-import-library}@anchor{285} +@subsubsection Creating an Import Library + + +@geindex Import library + +If a Microsoft-style import library @code{API.lib} or a GNAT-style +import library @code{libAPI.dll.a} or @code{libAPI.a} is available +with @code{API.dll} you can skip this section. You can also skip this +section if @code{API.dll} or @code{libAPI.dll} is built with GNU tools +as in this case it is possible to link directly against the +DLL. Otherwise read on. + +@geindex Definition file +@anchor{gnat_ugn/platform_specific_information the-definition-file}@anchor{280} +@subsubheading The Definition File + + +As previously mentioned, and unlike Unix systems, the list of symbols +that are exported from a DLL must be provided explicitly in Windows. +The main goal of a definition file is precisely that: list the symbols +exported by a DLL. A definition file (usually a file with a @cite{.def} +suffix) has the following structure: + +@quotation + +@example +[LIBRARY `name`] +[DESCRIPTION `string`] +EXPORTS + `symbol1` + `symbol2` + ... +@end example +@end quotation + + +@table @asis + +@item @emph{LIBRARY `name`} + +This section, which is optional, gives the name of the DLL. + +@item @emph{DESCRIPTION `string`} + +This section, which is optional, gives a description string that will be +embedded in the import library. + +@item @emph{EXPORTS} + +This section gives the list of exported symbols (procedures, functions or +variables). For instance in the case of @code{API.dll} the @cite{EXPORTS} +section of @code{API.def} looks like: + +@example +EXPORTS + some_var + get +@end example +@end table + +Note that you must specify the correct suffix (@code{@@@emph{nn}}) +(see @ref{274,,Windows Calling Conventions}) for a Stdcall +calling convention function in the exported symbols list. + +There can actually be other sections in a definition file, but these +sections are not relevant to the discussion at hand. + +@subsubheading GNAT-Style Import Library + +@anchor{gnat_ugn/platform_specific_information gnat-style-import-library}@anchor{286} +To create a static import library from @code{API.dll} with the GNAT tools +you should proceed as follows: + + +@itemize * + +@item +Create the definition file @code{API.def} +(see @ref{280,,The Definition File}). +For that use the @cite{dll2def} tool as follows: + +@example +$ dll2def API.dll > API.def +@end example + +@cite{dll2def} is a very simple tool: it takes as input a DLL and prints +to standard output the list of entry points in the DLL. Note that if +some routines in the DLL have the @cite{Stdcall} convention +(@ref{274,,Windows Calling Conventions}) with stripped @code{@@@emph{nn}} +suffix then you'll have to edit @code{api.def} to add it, and specify +@emph{-k} to @emph{gnatdll} when creating the import library. + +Here are some hints to find the right @code{@@@emph{nn}} suffix. + + +@itemize - + +@item +If you have the Microsoft import library (.lib), it is possible to get +the right symbols by using Microsoft @cite{dumpbin} tool (see the +corresponding Microsoft documentation for further details). + +@example +$ dumpbin /exports api.lib +@end example + +@item +If you have a message about a missing symbol at link time the compiler +tells you what symbol is expected. You just have to go back to the +definition file and add the right suffix. +@end itemize + +@item +Build the import library @cite{libAPI.dll.a}, using @cite{gnatdll} +(see @ref{287,,Using gnatdll}) as follows: + +@example +$ gnatdll -e API.def -d API.dll +@end example + +@cite{gnatdll} takes as input a definition file @code{API.def} and the +name of the DLL containing the services listed in the definition file +@code{API.dll}. The name of the static import library generated is +computed from the name of the definition file as follows: if the +definition file name is @cite{xyz`}.def`, the import library name will +be @cite{lib`@w{`}xyz`}.a`. Note that in the previous example option +@emph{-e} could have been removed because the name of the definition +file (before the '@cite{.def}' suffix) is the same as the name of the +DLL (@ref{287,,Using gnatdll} for more information about @cite{gnatdll}). +@end itemize + +@subsubheading Microsoft-Style Import Library + + +With GNAT you can either use a GNAT-style or Microsoft-style import +library. A Microsoft import library is needed only if you plan to make an +Ada DLL available to applications developed with Microsoft +tools (@ref{270,,Mixed-Language Programming on Windows}). + +To create a Microsoft-style import library for @code{API.dll} you +should proceed as follows: + + +@itemize * + +@item +Create the definition file @code{API.def} from the DLL. For this use either +the @cite{dll2def} tool as described above or the Microsoft @cite{dumpbin} +tool (see the corresponding Microsoft documentation for further details). + +@item +Build the actual import library using Microsoft's @cite{lib} utility: + +@example +$ lib -machine:IX86 -def:API.def -out:API.lib +@end example + +If you use the above command the definition file @code{API.def} must +contain a line giving the name of the DLL: + +@example +LIBRARY "API" +@end example + +See the Microsoft documentation for further details about the usage of +@cite{lib}. +@end itemize + +@node Building DLLs with GNAT Project files,Building DLLs with GNAT,Using DLLs with GNAT,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information id24}@anchor{288}@anchor{gnat_ugn/platform_specific_information building-dlls-with-gnat-project-files}@anchor{273} +@subsubsection Building DLLs with GNAT Project files + + +@geindex DLLs +@geindex building + +There is nothing specific to Windows in the build process. +@ref{8a,,Library Projects}. + +Due to a system limitation, it is not possible under Windows to create threads +when inside the @cite{DllMain} routine which is used for auto-initialization +of shared libraries, so it is not possible to have library level tasks in SALs. + +@node Building DLLs with GNAT,Building DLLs with gnatdll,Building DLLs with GNAT Project files,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information building-dlls-with-gnat}@anchor{289}@anchor{gnat_ugn/platform_specific_information id25}@anchor{28a} +@subsubsection Building DLLs with GNAT + + +@geindex DLLs +@geindex building + +This section explain how to build DLLs using the GNAT built-in DLL +support. With the following procedure it is straight forward to build +and use DLLs with GNAT. + + +@itemize * + +@item +Building object files. +The first step is to build all objects files that are to be included +into the DLL. This is done by using the standard @emph{gnatmake} tool. + +@item +Building the DLL. +To build the DLL you must use @emph{gcc}'s @emph{-shared} and +@emph{-shared-libgcc} options. It is quite simple to use this method: + +@example +$ gcc -shared -shared-libgcc -o api.dll obj1.o obj2.o ... +@end example + +It is important to note that in this case all symbols found in the +object files are automatically exported. It is possible to restrict +the set of symbols to export by passing to @emph{gcc} a definition +file (see @ref{280,,The Definition File}). +For example: + +@example +$ gcc -shared -shared-libgcc -o api.dll api.def obj1.o obj2.o ... +@end example + +If you use a definition file you must export the elaboration procedures +for every package that required one. Elaboration procedures are named +using the package name followed by "_E". + +@item +Preparing DLL to be used. +For the DLL to be used by client programs the bodies must be hidden +from it and the .ali set with read-only attribute. This is very important +otherwise GNAT will recompile all packages and will not actually use +the code in the DLL. For example: + +@example +$ mkdir apilib +$ copy *.ads *.ali api.dll apilib +$ attrib +R apilib\\*.ali +@end example +@end itemize + +At this point it is possible to use the DLL by directly linking +against it. Note that you must use the GNAT shared runtime when using +GNAT shared libraries. This is achieved by using @emph{-shared} binder's +option. + +@quotation + +@example +$ gnatmake main -Iapilib -bargs -shared -largs -Lapilib -lAPI +@end example +@end quotation + +@node Building DLLs with gnatdll,Ada DLLs and Finalization,Building DLLs with GNAT,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information building-dlls-with-gnatdll}@anchor{28b}@anchor{gnat_ugn/platform_specific_information id26}@anchor{28c} +@subsubsection Building DLLs with gnatdll + + +@geindex DLLs +@geindex building + +Note that it is preferred to use GNAT Project files +(@ref{273,,Building DLLs with GNAT Project files}) or the built-in GNAT +DLL support (@ref{289,,Building DLLs with GNAT}) or to build DLLs. + +This section explains how to build DLLs containing Ada code using +@cite{gnatdll}. These DLLs will be referred to as Ada DLLs in the +remainder of this section. + +The steps required to build an Ada DLL that is to be used by Ada as well as +non-Ada applications are as follows: + + +@itemize * + +@item +You need to mark each Ada @emph{entity} exported by the DLL with a @cite{C} or +@cite{Stdcall} calling convention to avoid any Ada name mangling for the +entities exported by the DLL +(see @ref{28d,,Exporting Ada Entities}). You can +skip this step if you plan to use the Ada DLL only from Ada applications. + +@item +Your Ada code must export an initialization routine which calls the routine +@cite{adainit} generated by @emph{gnatbind} to perform the elaboration of +the Ada code in the DLL (@ref{28e,,Ada DLLs and Elaboration}). The initialization +routine exported by the Ada DLL must be invoked by the clients of the DLL +to initialize the DLL. + +@item +When useful, the DLL should also export a finalization routine which calls +routine @cite{adafinal} generated by @emph{gnatbind} to perform the +finalization of the Ada code in the DLL (@ref{28f,,Ada DLLs and Finalization}). +The finalization routine exported by the Ada DLL must be invoked by the +clients of the DLL when the DLL services are no further needed. + +@item +You must provide a spec for the services exported by the Ada DLL in each +of the programming languages to which you plan to make the DLL available. + +@item +You must provide a definition file listing the exported entities +(@ref{280,,The Definition File}). + +@item +Finally you must use @cite{gnatdll} to produce the DLL and the import +library (@ref{287,,Using gnatdll}). +@end itemize + +Note that a relocatable DLL stripped using the @cite{strip} +binutils tool will not be relocatable anymore. To build a DLL without +debug information pass @cite{-largs -s} to @cite{gnatdll}. This +restriction does not apply to a DLL built using a Library Project. +See @ref{8a,,Library Projects}. + +@c Limitations_When_Using_Ada_DLLs_from Ada: + +@menu +* Limitations When Using Ada DLLs from Ada:: +* Exporting Ada Entities:: +* Ada DLLs and Elaboration:: + +@end menu + +@node Limitations When Using Ada DLLs from Ada,Exporting Ada Entities,,Building DLLs with gnatdll +@anchor{gnat_ugn/platform_specific_information limitations-when-using-ada-dlls-from-ada}@anchor{290} +@subsubsection Limitations When Using Ada DLLs from Ada + + +When using Ada DLLs from Ada applications there is a limitation users +should be aware of. Because on Windows the GNAT run time is not in a DLL of +its own, each Ada DLL includes a part of the GNAT run time. Specifically, +each Ada DLL includes the services of the GNAT run time that are necessary +to the Ada code inside the DLL. As a result, when an Ada program uses an +Ada DLL there are two independent GNAT run times: one in the Ada DLL and +one in the main program. + +It is therefore not possible to exchange GNAT run-time objects between the +Ada DLL and the main Ada program. Example of GNAT run-time objects are file +handles (e.g., @cite{Text_IO.File_Type}), tasks types, protected objects +types, etc. + +It is completely safe to exchange plain elementary, array or record types, +Windows object handles, etc. + +@node Exporting Ada Entities,Ada DLLs and Elaboration,Limitations When Using Ada DLLs from Ada,Building DLLs with gnatdll +@anchor{gnat_ugn/platform_specific_information exporting-ada-entities}@anchor{28d}@anchor{gnat_ugn/platform_specific_information id27}@anchor{291} +@subsubsection Exporting Ada Entities + + +@geindex Export table + +Building a DLL is a way to encapsulate a set of services usable from any +application. As a result, the Ada entities exported by a DLL should be +exported with the @cite{C} or @cite{Stdcall} calling conventions to avoid +any Ada name mangling. As an example here is an Ada package +@cite{API}, spec and body, exporting two procedures, a function, and a +variable: + +@quotation + +@example +with Interfaces.C; use Interfaces; +package API is + Count : C.int := 0; + function Factorial (Val : C.int) return C.int; + + procedure Initialize_API; + procedure Finalize_API; + -- Initialization & Finalization routines. More in the next section. +private + pragma Export (C, Initialize_API); + pragma Export (C, Finalize_API); + pragma Export (C, Count); + pragma Export (C, Factorial); +end API; +@end example + +@example +package body API is + function Factorial (Val : C.int) return C.int is + Fact : C.int := 1; + begin + Count := Count + 1; + for K in 1 .. Val loop + Fact := Fact * K; + end loop; + return Fact; + end Factorial; + + procedure Initialize_API is + procedure Adainit; + pragma Import (C, Adainit); + begin + Adainit; + end Initialize_API; + + procedure Finalize_API is + procedure Adafinal; + pragma Import (C, Adafinal); + begin + Adafinal; + end Finalize_API; +end API; +@end example +@end quotation + +If the Ada DLL you are building will only be used by Ada applications +you do not have to export Ada entities with a @cite{C} or @cite{Stdcall} +convention. As an example, the previous package could be written as +follows: + +@quotation + +@example +package API is + Count : Integer := 0; + function Factorial (Val : Integer) return Integer; + + procedure Initialize_API; + procedure Finalize_API; + -- Initialization and Finalization routines. +end API; +@end example + +@example +package body API is + function Factorial (Val : Integer) return Integer is + Fact : Integer := 1; + begin + Count := Count + 1; + for K in 1 .. Val loop + Fact := Fact * K; + end loop; + return Fact; + end Factorial; + + ... + -- The remainder of this package body is unchanged. +end API; +@end example +@end quotation + +Note that if you do not export the Ada entities with a @cite{C} or +@cite{Stdcall} convention you will have to provide the mangled Ada names +in the definition file of the Ada DLL +(@ref{292,,Creating the Definition File}). + +@node Ada DLLs and Elaboration,,Exporting Ada Entities,Building DLLs with gnatdll +@anchor{gnat_ugn/platform_specific_information ada-dlls-and-elaboration}@anchor{28e}@anchor{gnat_ugn/platform_specific_information id28}@anchor{293} +@subsubsection Ada DLLs and Elaboration + + +@geindex DLLs and elaboration + +The DLL that you are building contains your Ada code as well as all the +routines in the Ada library that are needed by it. The first thing a +user of your DLL must do is elaborate the Ada code +(@ref{11,,Elaboration Order Handling in GNAT}). + +To achieve this you must export an initialization routine +(@cite{Initialize_API} in the previous example), which must be invoked +before using any of the DLL services. This elaboration routine must call +the Ada elaboration routine @cite{adainit} generated by the GNAT binder +(@ref{ba,,Binding with Non-Ada Main Programs}). See the body of +@cite{Initialize_Api} for an example. Note that the GNAT binder is +automatically invoked during the DLL build process by the @cite{gnatdll} +tool (@ref{287,,Using gnatdll}). + +When a DLL is loaded, Windows systematically invokes a routine called +@cite{DllMain}. It would therefore be possible to call @cite{adainit} +directly from @cite{DllMain} without having to provide an explicit +initialization routine. Unfortunately, it is not possible to call +@cite{adainit} from the @cite{DllMain} if your program has library level +tasks because access to the @cite{DllMain} entry point is serialized by +the system (that is, only a single thread can execute 'through' it at a +time), which means that the GNAT run time will deadlock waiting for the +newly created task to complete its initialization. + +@node Ada DLLs and Finalization,Creating a Spec for Ada DLLs,Building DLLs with gnatdll,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information id29}@anchor{294}@anchor{gnat_ugn/platform_specific_information ada-dlls-and-finalization}@anchor{28f} +@subsubsection Ada DLLs and Finalization + + +@geindex DLLs and finalization + +When the services of an Ada DLL are no longer needed, the client code should +invoke the DLL finalization routine, if available. The DLL finalization +routine is in charge of releasing all resources acquired by the DLL. In the +case of the Ada code contained in the DLL, this is achieved by calling +routine @cite{adafinal} generated by the GNAT binder +(@ref{ba,,Binding with Non-Ada Main Programs}). +See the body of @cite{Finalize_Api} for an +example. As already pointed out the GNAT binder is automatically invoked +during the DLL build process by the @cite{gnatdll} tool +(@ref{287,,Using gnatdll}). + +@node Creating a Spec for Ada DLLs,GNAT and Windows Resources,Ada DLLs and Finalization,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information id30}@anchor{295}@anchor{gnat_ugn/platform_specific_information creating-a-spec-for-ada-dlls}@anchor{296} +@subsubsection Creating a Spec for Ada DLLs + + +To use the services exported by the Ada DLL from another programming +language (e.g., C), you have to translate the specs of the exported Ada +entities in that language. For instance in the case of @cite{API.dll}, +the corresponding C header file could look like: + +@quotation + +@example +extern int *_imp__count; +#define count (*_imp__count) +int factorial (int); +@end example +@end quotation + +It is important to understand that when building an Ada DLL to be used by +other Ada applications, you need two different specs for the packages +contained in the DLL: one for building the DLL and the other for using +the DLL. This is because the @cite{DLL} calling convention is needed to +use a variable defined in a DLL, but when building the DLL, the variable +must have either the @cite{Ada} or @cite{C} calling convention. As an +example consider a DLL comprising the following package @cite{API}: + +@quotation + +@example +package API is + Count : Integer := 0; + ... + -- Remainder of the package omitted. +end API; +@end example +@end quotation + +After producing a DLL containing package @cite{API}, the spec that +must be used to import @cite{API.Count} from Ada code outside of the +DLL is: + +@quotation + +@example +package API is + Count : Integer; + pragma Import (DLL, Count); +end API; +@end example +@end quotation + +@menu +* Creating the Definition File:: +* Using gnatdll:: + +@end menu + +@node Creating the Definition File,Using gnatdll,,Creating a Spec for Ada DLLs +@anchor{gnat_ugn/platform_specific_information creating-the-definition-file}@anchor{292}@anchor{gnat_ugn/platform_specific_information id31}@anchor{297} +@subsubsection Creating the Definition File + + +The definition file is the last file needed to build the DLL. It lists +the exported symbols. As an example, the definition file for a DLL +containing only package @cite{API} (where all the entities are exported +with a @cite{C} calling convention) is: + +@quotation + +@example +EXPORTS + count + factorial + finalize_api + initialize_api +@end example +@end quotation + +If the @cite{C} calling convention is missing from package @cite{API}, +then the definition file contains the mangled Ada names of the above +entities, which in this case are: + +@quotation + +@example +EXPORTS + api__count + api__factorial + api__finalize_api + api__initialize_api +@end example +@end quotation + +@node Using gnatdll,,Creating the Definition File,Creating a Spec for Ada DLLs +@anchor{gnat_ugn/platform_specific_information using-gnatdll}@anchor{287}@anchor{gnat_ugn/platform_specific_information id32}@anchor{298} +@subsubsection Using @cite{gnatdll} + + +@geindex gnatdll + +@cite{gnatdll} is a tool to automate the DLL build process once all the Ada +and non-Ada sources that make up your DLL have been compiled. +@cite{gnatdll} is actually in charge of two distinct tasks: build the +static import library for the DLL and the actual DLL. The form of the +@cite{gnatdll} command is + +@quotation + +@example +$ gnatdll [`switches`] `list-of-files` [-largs `opts`] +@end example +@end quotation + +where @cite{list-of-files} is a list of ALI and object files. The object +file list must be the exact list of objects corresponding to the non-Ada +sources whose services are to be included in the DLL. The ALI file list +must be the exact list of ALI files for the corresponding Ada sources +whose services are to be included in the DLL. If @cite{list-of-files} is +missing, only the static import library is generated. + +You may specify any of the following switches to @cite{gnatdll}: + +@quotation + +@geindex -a (gnatdll) +@end quotation + + +@table @asis + +@item @code{-a[@emph{address}]} + +Build a non-relocatable DLL at @cite{address}. If @cite{address} is not +specified the default address @cite{0x11000000} will be used. By default, +when this switch is missing, @cite{gnatdll} builds relocatable DLL. We +advise the reader to build relocatable DLL. + +@geindex -b (gnatdll) + +@item @code{-b @emph{address}} + +Set the relocatable DLL base address. By default the address is +@cite{0x11000000}. + +@geindex -bargs (gnatdll) + +@item @code{-bargs @emph{opts}} + +Binder options. Pass @cite{opts} to the binder. + +@geindex -d (gnatdll) + +@item @code{-d @emph{dllfile}} + +@cite{dllfile} is the name of the DLL. This switch must be present for +@cite{gnatdll} to do anything. The name of the generated import library is +obtained algorithmically from @cite{dllfile} as shown in the following +example: if @cite{dllfile} is @cite{xyz.dll}, the import library name is +@cite{libxyz.dll.a}. The name of the definition file to use (if not specified +by option @emph{-e}) is obtained algorithmically from @cite{dllfile} +as shown in the following example: +if @cite{dllfile} is @cite{xyz.dll}, the definition +file used is @cite{xyz.def}. + +@geindex -e (gnatdll) + +@item @code{-e @emph{deffile}} + +@cite{deffile} is the name of the definition file. + +@geindex -g (gnatdll) + +@item @code{-g} + +Generate debugging information. This information is stored in the object +file and copied from there to the final DLL file by the linker, +where it can be read by the debugger. You must use the +@emph{-g} switch if you plan on using the debugger or the symbolic +stack traceback. + +@geindex -h (gnatdll) + +@item @code{-h} + +Help mode. Displays @cite{gnatdll} switch usage information. + +@geindex -I (gnatdll) + +@item @code{-I@emph{dir}} + +Direct @cite{gnatdll} to search the @cite{dir} directory for source and +object files needed to build the DLL. +(@ref{8e,,Search Paths and the Run-Time Library (RTL)}). + +@geindex -k (gnatdll) + +@item @code{-k} + +Removes the @code{@@@emph{nn}} suffix from the import library's exported +names, but keeps them for the link names. You must specify this +option if you want to use a @cite{Stdcall} function in a DLL for which +the @code{@@@emph{nn}} suffix has been removed. This is the case for most +of the Windows NT DLL for example. This option has no effect when +@emph{-n} option is specified. + +@geindex -l (gnatdll) + +@item @code{-l @emph{file}} + +The list of ALI and object files used to build the DLL are listed in +@cite{file}, instead of being given in the command line. Each line in +@cite{file} contains the name of an ALI or object file. + +@geindex -n (gnatdll) + +@item @code{-n} + +No Import. Do not create the import library. + +@geindex -q (gnatdll) + +@item @code{-q} + +Quiet mode. Do not display unnecessary messages. + +@geindex -v (gnatdll) + +@item @code{-v} + +Verbose mode. Display extra information. + +@geindex -largs (gnatdll) + +@item @code{-largs @emph{opts}} + +Linker options. Pass @cite{opts} to the linker. +@end table + +@subsubheading @cite{gnatdll} Example + + +As an example the command to build a relocatable DLL from @code{api.adb} +once @code{api.adb} has been compiled and @code{api.def} created is + +@quotation + +@example +$ gnatdll -d api.dll api.ali +@end example +@end quotation + +The above command creates two files: @code{libapi.dll.a} (the import +library) and @code{api.dll} (the actual DLL). If you want to create +only the DLL, just type: + +@quotation + +@example +$ gnatdll -d api.dll -n api.ali +@end example +@end quotation + +Alternatively if you want to create just the import library, type: + +@quotation + +@example +$ gnatdll -d api.dll +@end example +@end quotation + +@subsubheading @cite{gnatdll} behind the Scenes + + +This section details the steps involved in creating a DLL. @cite{gnatdll} +does these steps for you. Unless you are interested in understanding what +goes on behind the scenes, you should skip this section. + +We use the previous example of a DLL containing the Ada package @cite{API}, +to illustrate the steps necessary to build a DLL. The starting point is a +set of objects that will make up the DLL and the corresponding ALI +files. In the case of this example this means that @code{api.o} and +@code{api.ali} are available. To build a relocatable DLL, @cite{gnatdll} does +the following: + + +@itemize * + +@item +@cite{gnatdll} builds the base file (@code{api.base}). A base file gives +the information necessary to generate relocation information for the +DLL. + +@example +$ gnatbind -n api +$ gnatlink api -o api.jnk -mdll -Wl,--base-file,api.base +@end example + +In addition to the base file, the @emph{gnatlink} command generates an +output file @code{api.jnk} which can be discarded. The @emph{-mdll} switch +asks @emph{gnatlink} to generate the routines @cite{DllMain} and +@cite{DllMainCRTStartup} that are called by the Windows loader when the DLL +is loaded into memory. + +@item +@cite{gnatdll} uses @cite{dlltool} (see @ref{299,,Using dlltool}) to build the +export table (@code{api.exp}). The export table contains the relocation +information in a form which can be used during the final link to ensure +that the Windows loader is able to place the DLL anywhere in memory. + +@example +$ dlltool --dllname api.dll --def api.def --base-file api.base \\ + --output-exp api.exp +@end example + +@item +@cite{gnatdll} builds the base file using the new export table. Note that +@emph{gnatbind} must be called once again since the binder generated file +has been deleted during the previous call to @emph{gnatlink}. + +@example +$ gnatbind -n api +$ gnatlink api -o api.jnk api.exp -mdll + -Wl,--base-file,api.base +@end example + +@item +@cite{gnatdll} builds the new export table using the new base file and +generates the DLL import library @code{libAPI.dll.a}. + +@example +$ dlltool --dllname api.dll --def api.def --base-file api.base \\ + --output-exp api.exp --output-lib libAPI.a +@end example + +@item +Finally @cite{gnatdll} builds the relocatable DLL using the final export +table. + +@example +$ gnatbind -n api +$ gnatlink api api.exp -o api.dll -mdll +@end example +@end itemize +@anchor{gnat_ugn/platform_specific_information using-dlltool}@anchor{299} +@subsubheading Using @cite{dlltool} + + +@cite{dlltool} is the low-level tool used by @cite{gnatdll} to build +DLLs and static import libraries. This section summarizes the most +common @cite{dlltool} switches. The form of the @cite{dlltool} command +is + +@quotation + +@example +$ dlltool [`switches`] +@end example +@end quotation + +@cite{dlltool} switches include: + +@geindex --base-file (dlltool) + + +@table @asis + +@item @code{--base-file @emph{basefile}} + +Read the base file @cite{basefile} generated by the linker. This switch +is used to create a relocatable DLL. +@end table + +@geindex --def (dlltool) + + +@table @asis + +@item @code{--def @emph{deffile}} + +Read the definition file. +@end table + +@geindex --dllname (dlltool) + + +@table @asis + +@item @code{--dllname @emph{name}} + +Gives the name of the DLL. This switch is used to embed the name of the +DLL in the static import library generated by @cite{dlltool} with switch +@emph{--output-lib}. +@end table + +@geindex -k (dlltool) + + +@table @asis + +@item @code{-k} + +Kill @code{@@@emph{nn}} from exported names +(@ref{274,,Windows Calling Conventions} +for a discussion about @cite{Stdcall}-style symbols. +@end table + +@geindex --help (dlltool) + + +@table @asis + +@item @code{--help} + +Prints the @cite{dlltool} switches with a concise description. +@end table + +@geindex --output-exp (dlltool) + + +@table @asis + +@item @code{--output-exp @emph{exportfile}} + +Generate an export file @cite{exportfile}. The export file contains the +export table (list of symbols in the DLL) and is used to create the DLL. +@end table + +@geindex --output-lib (dlltool) + + +@table @asis + +@item @code{--output-lib @emph{libfile}} + +Generate a static import library @cite{libfile}. +@end table + +@geindex -v (dlltool) + + +@table @asis + +@item @code{-v} + +Verbose mode. +@end table + +@geindex --as (dlltool) + + +@table @asis + +@item @code{--as @emph{assembler-name}} + +Use @cite{assembler-name} as the assembler. The default is @cite{as}. +@end table + +@node GNAT and Windows Resources,Debugging a DLL,Creating a Spec for Ada DLLs,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information gnat-and-windows-resources}@anchor{29a}@anchor{gnat_ugn/platform_specific_information id33}@anchor{29b} +@subsubsection GNAT and Windows Resources + + +@geindex Resources +@geindex windows + +Resources are an easy way to add Windows specific objects to your +application. The objects that can be added as resources include: + + +@itemize * + +@item +menus + +@item +accelerators + +@item +dialog boxes + +@item +string tables + +@item +bitmaps + +@item +cursors + +@item +icons + +@item +fonts + +@item +version information +@end itemize + +For example, a version information resource can be defined as follow and +embedded into an executable or DLL: + +A version information resource can be used to embed information into an +executable or a DLL. These information can be viewed using the file properties +from the Windows Explorer. Here is an example of a version information +resource: + +@quotation + +@example +1 VERSIONINFO +FILEVERSION 1,0,0,0 +PRODUCTVERSION 1,0,0,0 +BEGIN + BLOCK "StringFileInfo" + BEGIN + BLOCK "080904E4" + BEGIN + VALUE "CompanyName", "My Company Name" + VALUE "FileDescription", "My application" + VALUE "FileVersion", "1.0" + VALUE "InternalName", "my_app" + VALUE "LegalCopyright", "My Name" + VALUE "OriginalFilename", "my_app.exe" + VALUE "ProductName", "My App" + VALUE "ProductVersion", "1.0" + END + END + + BLOCK "VarFileInfo" + BEGIN + VALUE "Translation", 0x809, 1252 + END +END +@end example +@end quotation + +The value @cite{0809} (langID) is for the U.K English language and +@cite{04E4} (charsetID), which is equal to @cite{1252} decimal, for +multilingual. + +This section explains how to build, compile and use resources. Note that this +section does not cover all resource objects, for a complete description see +the corresponding Microsoft documentation. + +@menu +* Building Resources:: +* Compiling Resources:: +* Using Resources:: + +@end menu + +@node Building Resources,Compiling Resources,,GNAT and Windows Resources +@anchor{gnat_ugn/platform_specific_information building-resources}@anchor{29c}@anchor{gnat_ugn/platform_specific_information id34}@anchor{29d} +@subsubsection Building Resources + + +@geindex Resources +@geindex building + +A resource file is an ASCII file. By convention resource files have an +@code{.rc} extension. +The easiest way to build a resource file is to use Microsoft tools +such as @cite{imagedit.exe} to build bitmaps, icons and cursors and +@cite{dlgedit.exe} to build dialogs. +It is always possible to build an @code{.rc} file yourself by writing a +resource script. + +It is not our objective to explain how to write a resource file. A +complete description of the resource script language can be found in the +Microsoft documentation. + +@node Compiling Resources,Using Resources,Building Resources,GNAT and Windows Resources +@anchor{gnat_ugn/platform_specific_information compiling-resources}@anchor{29e}@anchor{gnat_ugn/platform_specific_information id35}@anchor{29f} +@subsubsection Compiling Resources + + +@geindex rc + +@geindex windres + +@geindex Resources +@geindex compiling + +This section describes how to build a GNAT-compatible (COFF) object file +containing the resources. This is done using the Resource Compiler +@cite{windres} as follows: + +@quotation + +@example +$ windres -i myres.rc -o myres.o +@end example +@end quotation + +By default @cite{windres} will run @emph{gcc} to preprocess the @code{.rc} +file. You can specify an alternate preprocessor (usually named +@code{cpp.exe}) using the @cite{windres} @emph{--preprocessor} +parameter. A list of all possible options may be obtained by entering +the command @cite{windres} @emph{--help}. + +It is also possible to use the Microsoft resource compiler @cite{rc.exe} +to produce a @code{.res} file (binary resource file). See the +corresponding Microsoft documentation for further details. In this case +you need to use @cite{windres} to translate the @code{.res} file to a +GNAT-compatible object file as follows: + +@quotation + +@example +$ windres -i myres.res -o myres.o +@end example +@end quotation + +@node Using Resources,,Compiling Resources,GNAT and Windows Resources +@anchor{gnat_ugn/platform_specific_information id36}@anchor{2a0}@anchor{gnat_ugn/platform_specific_information using-resources}@anchor{2a1} +@subsubsection Using Resources + + +@geindex Resources +@geindex using + +To include the resource file in your program just add the +GNAT-compatible object file for the resource(s) to the linker +arguments. With @emph{gnatmake} this is done by using the @emph{-largs} +option: + +@quotation + +@example +$ gnatmake myprog -largs myres.o +@end example +@end quotation + +@node Debugging a DLL,Setting Stack Size from gnatlink,GNAT and Windows Resources,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information id37}@anchor{2a2}@anchor{gnat_ugn/platform_specific_information debugging-a-dll}@anchor{2a3} +@subsubsection Debugging a DLL + + +@geindex DLL debugging + +Debugging a DLL is similar to debugging a standard program. But +we have to deal with two different executable parts: the DLL and the +program that uses it. We have the following four possibilities: + + +@itemize * + +@item +The program and the DLL are built with @cite{GCC/GNAT}. + +@item +The program is built with foreign tools and the DLL is built with +@cite{GCC/GNAT}. + +@item +The program is built with @cite{GCC/GNAT} and the DLL is built with +foreign tools. +@end itemize + +In this section we address only cases one and two above. +There is no point in trying to debug +a DLL with @cite{GNU/GDB}, if there is no GDB-compatible debugging +information in it. To do so you must use a debugger compatible with the +tools suite used to build the DLL. + +@menu +* Program and DLL Both Built with GCC/GNAT:: +* Program Built with Foreign Tools and DLL Built with GCC/GNAT:: + +@end menu + +@node Program and DLL Both Built with GCC/GNAT,Program Built with Foreign Tools and DLL Built with GCC/GNAT,,Debugging a DLL +@anchor{gnat_ugn/platform_specific_information program-and-dll-both-built-with-gcc-gnat}@anchor{2a4}@anchor{gnat_ugn/platform_specific_information id38}@anchor{2a5} +@subsubsection Program and DLL Both Built with GCC/GNAT + + +This is the simplest case. Both the DLL and the program have @cite{GDB} +compatible debugging information. It is then possible to break anywhere in +the process. Let's suppose here that the main procedure is named +@cite{ada_main} and that in the DLL there is an entry point named +@cite{ada_dll}. + +The DLL (@ref{27f,,Introduction to Dynamic Link Libraries (DLLs)}) and +program must have been built with the debugging information (see GNAT -g +switch). Here are the step-by-step instructions for debugging it: + + +@itemize * + +@item +Launch @cite{GDB} on the main program. + +@example +$ gdb -nw ada_main +@end example + +@item +Start the program and stop at the beginning of the main procedure + +@example +(gdb) start +@end example + +This step is required to be able to set a breakpoint inside the DLL. As long +as the program is not run, the DLL is not loaded. This has the +consequence that the DLL debugging information is also not loaded, so it is not +possible to set a breakpoint in the DLL. + +@item +Set a breakpoint inside the DLL + +@example +(gdb) break ada_dll +(gdb) cont +@end example +@end itemize + +At this stage a breakpoint is set inside the DLL. From there on +you can use the standard approach to debug the whole program +(@ref{26,,Running and Debugging Ada Programs}). + +@node Program Built with Foreign Tools and DLL Built with GCC/GNAT,,Program and DLL Both Built with GCC/GNAT,Debugging a DLL +@anchor{gnat_ugn/platform_specific_information program-built-with-foreign-tools-and-dll-built-with-gcc-gnat}@anchor{2a6}@anchor{gnat_ugn/platform_specific_information id39}@anchor{2a7} +@subsubsection Program Built with Foreign Tools and DLL Built with GCC/GNAT + + +In this case things are slightly more complex because it is not possible to +start the main program and then break at the beginning to load the DLL and the +associated DLL debugging information. It is not possible to break at the +beginning of the program because there is no @cite{GDB} debugging information, +and therefore there is no direct way of getting initial control. This +section addresses this issue by describing some methods that can be used +to break somewhere in the DLL to debug it. + +First suppose that the main procedure is named @cite{main} (this is for +example some C code built with Microsoft Visual C) and that there is a +DLL named @cite{test.dll} containing an Ada entry point named +@cite{ada_dll}. + +The DLL (see @ref{27f,,Introduction to Dynamic Link Libraries (DLLs)}) must have +been built with debugging information (see GNAT @cite{-g} option). + +@subsubheading Debugging the DLL Directly + + + +@itemize * + +@item +Find out the executable starting address + +@example +$ objdump --file-header main.exe +@end example + +The starting address is reported on the last line. For example: + +@example +main.exe: file format pei-i386 +architecture: i386, flags 0x0000010a: +EXEC_P, HAS_DEBUG, D_PAGED +start address 0x00401010 +@end example + +@item +Launch the debugger on the executable. + +@example +$ gdb main.exe +@end example + +@item +Set a breakpoint at the starting address, and launch the program. + +@example +$ (gdb) break *0x00401010 +$ (gdb) run +@end example + +The program will stop at the given address. + +@item +Set a breakpoint on a DLL subroutine. + +@example +(gdb) break ada_dll.adb:45 +@end example + +Or if you want to break using a symbol on the DLL, you need first to +select the Ada language (language used by the DLL). + +@example +(gdb) set language ada +(gdb) break ada_dll +@end example + +@item +Continue the program. + +@example +(gdb) cont +@end example + +This will run the program until it reaches the breakpoint that has been +set. From that point you can use the standard way to debug a program +as described in (@ref{26,,Running and Debugging Ada Programs}). +@end itemize + +It is also possible to debug the DLL by attaching to a running process. + +@subsubheading Attaching to a Running Process + + +@geindex DLL debugging +@geindex attach to process + +With @cite{GDB} it is always possible to debug a running process by +attaching to it. It is possible to debug a DLL this way. The limitation +of this approach is that the DLL must run long enough to perform the +attach operation. It may be useful for instance to insert a time wasting +loop in the code of the DLL to meet this criterion. + + +@itemize * + +@item +Launch the main program @code{main.exe}. + +@example +$ main +@end example + +@item +Use the Windows @emph{Task Manager} to find the process ID. Let's say +that the process PID for @code{main.exe} is 208. + +@item +Launch gdb. + +@example +$ gdb +@end example + +@item +Attach to the running process to be debugged. + +@example +(gdb) attach 208 +@end example + +@item +Load the process debugging information. + +@example +(gdb) symbol-file main.exe +@end example + +@item +Break somewhere in the DLL. + +@example +(gdb) break ada_dll +@end example + +@item +Continue process execution. + +@example +(gdb) cont +@end example +@end itemize + +This last step will resume the process execution, and stop at +the breakpoint we have set. From there you can use the standard +approach to debug a program as described in +@ref{26,,Running and Debugging Ada Programs}. + +@node Setting Stack Size from gnatlink,Setting Heap Size from gnatlink,Debugging a DLL,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information setting-stack-size-from-gnatlink}@anchor{13a}@anchor{gnat_ugn/platform_specific_information id40}@anchor{2a8} +@subsubsection Setting Stack Size from @emph{gnatlink} + + +It is possible to specify the program stack size at link time. On modern +versions of Windows, starting with XP, this is mostly useful to set the size of +the main stack (environment task). The other task stacks are set with pragma +Storage_Size or with the @emph{gnatbind -d} command. + +Since older versions of Windows (2000, NT4, etc.) do not allow setting the +reserve size of individual tasks, the link-time stack size applies to all +tasks, and pragma Storage_Size has no effect. +In particular, Stack Overflow checks are made against this +link-time specified size. + +This setting can be done with @emph{gnatlink} using either of the following: + + +@itemize * + +@item +@emph{-Xlinker} linker option + +@example +$ gnatlink hello -Xlinker --stack=0x10000,0x1000 +@end example + +This sets the stack reserve size to 0x10000 bytes and the stack commit +size to 0x1000 bytes. + +@item +@emph{-Wl} linker option + +@example +$ gnatlink hello -Wl,--stack=0x1000000 +@end example + +This sets the stack reserve size to 0x1000000 bytes. Note that with +@emph{-Wl} option it is not possible to set the stack commit size +because the coma is a separator for this option. @end itemize -@noindent -To specify the @code{Round_Robin_Within_Priorities}, scheduling policy -you should use @code{pragma Time_Slice} with a -value greater than @code{0.0}, or use the corresponding @option{-T} -binder option, or set the @code{pragma Task_Dispatching_Policy -(Round_Robin_Within_Priorities)}. +@node Setting Heap Size from gnatlink,,Setting Stack Size from gnatlink,Mixed-Language Programming on Windows +@anchor{gnat_ugn/platform_specific_information setting-heap-size-from-gnatlink}@anchor{13b}@anchor{gnat_ugn/platform_specific_information id41}@anchor{2a9} +@subsubsection Setting Heap Size from @emph{gnatlink} + + +Under Windows systems, it is possible to specify the program heap size from +@emph{gnatlink} using either of the following: + + +@itemize * -@c ******************************* -@node Example of Binder Output File -@appendix Example of Binder Output File +@item +@emph{-Xlinker} linker option -@noindent -This Appendix displays the source code for @command{gnatbind}'s output -file generated for a simple ``Hello World'' program. +@example +$ gnatlink hello -Xlinker --heap=0x10000,0x1000 +@end example + +This sets the heap reserve size to 0x10000 bytes and the heap commit +size to 0x1000 bytes. + +@item +@emph{-Wl} linker option + +@example +$ gnatlink hello -Wl,--heap=0x1000000 +@end example + +This sets the heap reserve size to 0x1000000 bytes. Note that with +@emph{-Wl} option it is not possible to set the heap commit size +because the coma is a separator for this option. +@end itemize + +@node Mac OS Topics,,Microsoft Windows Topics,Platform-Specific Information +@anchor{gnat_ugn/platform_specific_information mac-os-topics}@anchor{2f}@anchor{gnat_ugn/platform_specific_information id42}@anchor{2aa} +@section Mac OS Topics + + +@geindex OS X + +This section describes topics that are specific to Apple's OS X +platform. + +@menu +* Codesigning the Debugger:: + +@end menu + +@node Codesigning the Debugger,,,Mac OS Topics +@anchor{gnat_ugn/platform_specific_information codesigning-the-debugger}@anchor{2ab} +@subsection Codesigning the Debugger + + +The Darwin Kernel requires the debugger to have special permissions +before it is allowed to control other processes. These permissions +are granted by codesigning the GDB executable. Without these +permissions, the debugger will report error messages such as: + +@example +Starting program: /x/y/foo +Unable to find Mach task port for process-id 28885: (os/kern) failure (0x5). +(please check gdb is codesigned - see taskgated(8)) +@end example + +Codesigning requires a certificate. The following procedure explains +how to create one: + + +@itemize * + +@item +Start the Keychain Access application (in +/Applications/Utilities/Keychain Access.app) + +@item +Select the Keychain Access -> Certificate Assistant -> +Create a Certificate... menu + +@item +Then: + + +@itemize * + +@item +Choose a name for the new certificate (this procedure will use +"gdb-cert" as an example) + +@item +Set "Identity Type" to "Self Signed Root" + +@item +Set "Certificate Type" to "Code Signing" + +@item +Activate the "Let me override defaults" option +@end itemize + +@item +Click several times on "Continue" until the "Specify a Location +For The Certificate" screen appears, then set "Keychain" to "System" + +@item +Click on "Continue" until the certificate is created + +@item +Finally, in the view, double-click on the new certificate, +and set "When using this certificate" to "Always Trust" + +@item +Exit the Keychain Access application and restart the computer +(this is unfortunately required) +@end itemize + +Once a certificate has been created, the debugger can be codesigned +as follow. In a Terminal, run the following command: + +@quotation + +@example +$ codesign -f -s "gdb-cert" <gnat_install_prefix>/bin/gdb +@end example +@end quotation + +where "gdb-cert" should be replaced by the actual certificate +name chosen above, and <gnat_install_prefix> should be replaced by +the location where you installed GNAT. Also, be sure that users are +in the Unix group @code{_developer}. + +@node Example of Binder Output File,Elaboration Order Handling in GNAT,Platform-Specific Information,Top +@anchor{gnat_ugn/example_of_binder_output example-of-binder-output-file}@anchor{10}@anchor{gnat_ugn/example_of_binder_output doc}@anchor{2ac}@anchor{gnat_ugn/example_of_binder_output id1}@anchor{2ad} +@chapter Example of Binder Output File + + +@geindex Binder output (example) + +This Appendix displays the source code for the output file +generated by @emph{gnatbind} for a simple 'Hello World' program. Comments have been added for clarification purposes. -@smallexample @c adanocomment -@iftex -@leftskip=0cm -@end iftex +@example -- The package is called Ada_Main unless this name is actually used -- as a unit name in the partition, in which case some other unique -- name is used. -@b{pragma} Ada_95; -@b{with} System; -@b{package} ada_main @b{is} - @b{pragma} Warnings (Off); +pragma Ada_95; +with System; +package ada_main is + pragma Warnings (Off); -- The main program saves the parameters (argument count, -- argument values, environment pointer) in global variables @@ -22357,37 +32092,37 @@ Comments have been added for clarification purposes. -- is useful for some shared library situations, where there -- are problems if variables are not in the library. - @b{pragma} Import (C, gnat_argc); - @b{pragma} Import (C, gnat_argv); - @b{pragma} Import (C, gnat_envp); + pragma Import (C, gnat_argc); + pragma Import (C, gnat_argv); + pragma Import (C, gnat_envp); -- The exit status is similarly an external location gnat_exit_status : Integer; - @b{pragma} Import (C, gnat_exit_status); + pragma Import (C, gnat_exit_status); - GNAT_Version : @b{constant} String := + GNAT_Version : constant String := "GNAT Version: Pro 7.4.0w (20141119-49)" & ASCII.NUL; - @b{pragma} Export (C, GNAT_Version, "__gnat_version"); + pragma Export (C, GNAT_Version, "__gnat_version"); Ada_Main_Program_Name : constant String := "_ada_hello" & ASCII.NUL; - @b{pragma} Export (C, Ada_Main_Program_Name, "__gnat_ada_main_program_name"); + pragma Export (C, Ada_Main_Program_Name, "__gnat_ada_main_program_name"); -- This is the generated adainit routine that performs -- initialization at the start of execution. In the case -- where Ada is the main program, this main program makes -- a call to adainit at program startup. - @b{procedure} adainit; - @b{pragma} Export (C, adainit, "adainit"); + procedure adainit; + pragma Export (C, adainit, "adainit"); -- This is the generated adafinal routine that performs -- finalization at the end of execution. In the case where -- Ada is the main program, this main program makes a call -- to adafinal at program termination. - @b{procedure} adafinal; - @b{pragma} Export (C, adafinal, "adafinal"); + procedure adafinal; + pragma Export (C, adafinal, "adafinal"); -- This routine is called at the start of execution. It is -- a dummy routine that is used by the debugger to breakpoint @@ -22398,12 +32133,12 @@ Comments have been added for clarification purposes. -- required by standard system conventions, this program has -- the external name main. - @b{function} main + function main (argc : Integer; argv : System.Address; envp : System.Address) - @b{return} Integer; - @b{pragma} Export (C, main, "main"); + return Integer; + pragma Export (C, main, "main"); -- The following set of constants give the version -- identification values for every unit in the bound @@ -22418,194 +32153,193 @@ Comments have been added for clarification purposes. -- information provided here is sufficient to track down -- the exact versions of units used in a given build. - - @b{type} Version_32 @b{is} @b{mod} 2 ** 32; - u00001 : @b{constant} Version_32 := 16#8ad6e54a#; - @b{pragma} Export (C, u00001, "helloB"); - u00002 : @b{constant} Version_32 := 16#fbff4c67#; - @b{pragma} Export (C, u00002, "system__standard_libraryB"); - u00003 : @b{constant} Version_32 := 16#1ec6fd90#; - @b{pragma} Export (C, u00003, "system__standard_libraryS"); - u00004 : @b{constant} Version_32 := 16#3ffc8e18#; - @b{pragma} Export (C, u00004, "adaS"); - u00005 : @b{constant} Version_32 := 16#28f088c2#; - @b{pragma} Export (C, u00005, "ada__text_ioB"); - u00006 : @b{constant} Version_32 := 16#f372c8ac#; - @b{pragma} Export (C, u00006, "ada__text_ioS"); - u00007 : @b{constant} Version_32 := 16#2c143749#; - @b{pragma} Export (C, u00007, "ada__exceptionsB"); - u00008 : @b{constant} Version_32 := 16#f4f0cce8#; - @b{pragma} Export (C, u00008, "ada__exceptionsS"); - u00009 : @b{constant} Version_32 := 16#a46739c0#; - @b{pragma} Export (C, u00009, "ada__exceptions__last_chance_handlerB"); - u00010 : @b{constant} Version_32 := 16#3aac8c92#; - @b{pragma} Export (C, u00010, "ada__exceptions__last_chance_handlerS"); - u00011 : @b{constant} Version_32 := 16#1d274481#; - @b{pragma} Export (C, u00011, "systemS"); - u00012 : @b{constant} Version_32 := 16#a207fefe#; - @b{pragma} Export (C, u00012, "system__soft_linksB"); - u00013 : @b{constant} Version_32 := 16#467d9556#; - @b{pragma} Export (C, u00013, "system__soft_linksS"); - u00014 : @b{constant} Version_32 := 16#b01dad17#; - @b{pragma} Export (C, u00014, "system__parametersB"); - u00015 : @b{constant} Version_32 := 16#630d49fe#; - @b{pragma} Export (C, u00015, "system__parametersS"); - u00016 : @b{constant} Version_32 := 16#b19b6653#; - @b{pragma} Export (C, u00016, "system__secondary_stackB"); - u00017 : @b{constant} Version_32 := 16#b6468be8#; - @b{pragma} Export (C, u00017, "system__secondary_stackS"); - u00018 : @b{constant} Version_32 := 16#39a03df9#; - @b{pragma} Export (C, u00018, "system__storage_elementsB"); - u00019 : @b{constant} Version_32 := 16#30e40e85#; - @b{pragma} Export (C, u00019, "system__storage_elementsS"); - u00020 : @b{constant} Version_32 := 16#41837d1e#; - @b{pragma} Export (C, u00020, "system__stack_checkingB"); - u00021 : @b{constant} Version_32 := 16#93982f69#; - @b{pragma} Export (C, u00021, "system__stack_checkingS"); - u00022 : @b{constant} Version_32 := 16#393398c1#; - @b{pragma} Export (C, u00022, "system__exception_tableB"); - u00023 : @b{constant} Version_32 := 16#b33e2294#; - @b{pragma} Export (C, u00023, "system__exception_tableS"); - u00024 : @b{constant} Version_32 := 16#ce4af020#; - @b{pragma} Export (C, u00024, "system__exceptionsB"); - u00025 : @b{constant} Version_32 := 16#75442977#; - @b{pragma} Export (C, u00025, "system__exceptionsS"); - u00026 : @b{constant} Version_32 := 16#37d758f1#; - @b{pragma} Export (C, u00026, "system__exceptions__machineS"); - u00027 : @b{constant} Version_32 := 16#b895431d#; - @b{pragma} Export (C, u00027, "system__exceptions_debugB"); - u00028 : @b{constant} Version_32 := 16#aec55d3f#; - @b{pragma} Export (C, u00028, "system__exceptions_debugS"); - u00029 : @b{constant} Version_32 := 16#570325c8#; - @b{pragma} Export (C, u00029, "system__img_intB"); - u00030 : @b{constant} Version_32 := 16#1ffca443#; - @b{pragma} Export (C, u00030, "system__img_intS"); - u00031 : @b{constant} Version_32 := 16#b98c3e16#; - @b{pragma} Export (C, u00031, "system__tracebackB"); - u00032 : @b{constant} Version_32 := 16#831a9d5a#; - @b{pragma} Export (C, u00032, "system__tracebackS"); - u00033 : @b{constant} Version_32 := 16#9ed49525#; - @b{pragma} Export (C, u00033, "system__traceback_entriesB"); - u00034 : @b{constant} Version_32 := 16#1d7cb2f1#; - @b{pragma} Export (C, u00034, "system__traceback_entriesS"); - u00035 : @b{constant} Version_32 := 16#8c33a517#; - @b{pragma} Export (C, u00035, "system__wch_conB"); - u00036 : @b{constant} Version_32 := 16#065a6653#; - @b{pragma} Export (C, u00036, "system__wch_conS"); - u00037 : @b{constant} Version_32 := 16#9721e840#; - @b{pragma} Export (C, u00037, "system__wch_stwB"); - u00038 : @b{constant} Version_32 := 16#2b4b4a52#; - @b{pragma} Export (C, u00038, "system__wch_stwS"); - u00039 : @b{constant} Version_32 := 16#92b797cb#; - @b{pragma} Export (C, u00039, "system__wch_cnvB"); - u00040 : @b{constant} Version_32 := 16#09eddca0#; - @b{pragma} Export (C, u00040, "system__wch_cnvS"); - u00041 : @b{constant} Version_32 := 16#6033a23f#; - @b{pragma} Export (C, u00041, "interfacesS"); - u00042 : @b{constant} Version_32 := 16#ece6fdb6#; - @b{pragma} Export (C, u00042, "system__wch_jisB"); - u00043 : @b{constant} Version_32 := 16#899dc581#; - @b{pragma} Export (C, u00043, "system__wch_jisS"); - u00044 : @b{constant} Version_32 := 16#10558b11#; - @b{pragma} Export (C, u00044, "ada__streamsB"); - u00045 : @b{constant} Version_32 := 16#2e6701ab#; - @b{pragma} Export (C, u00045, "ada__streamsS"); - u00046 : @b{constant} Version_32 := 16#db5c917c#; - @b{pragma} Export (C, u00046, "ada__io_exceptionsS"); - u00047 : @b{constant} Version_32 := 16#12c8cd7d#; - @b{pragma} Export (C, u00047, "ada__tagsB"); - u00048 : @b{constant} Version_32 := 16#ce72c228#; - @b{pragma} Export (C, u00048, "ada__tagsS"); - u00049 : @b{constant} Version_32 := 16#c3335bfd#; - @b{pragma} Export (C, u00049, "system__htableB"); - u00050 : @b{constant} Version_32 := 16#99e5f76b#; - @b{pragma} Export (C, u00050, "system__htableS"); - u00051 : @b{constant} Version_32 := 16#089f5cd0#; - @b{pragma} Export (C, u00051, "system__string_hashB"); - u00052 : @b{constant} Version_32 := 16#3bbb9c15#; - @b{pragma} Export (C, u00052, "system__string_hashS"); - u00053 : @b{constant} Version_32 := 16#807fe041#; - @b{pragma} Export (C, u00053, "system__unsigned_typesS"); - u00054 : @b{constant} Version_32 := 16#d27be59e#; - @b{pragma} Export (C, u00054, "system__val_lluB"); - u00055 : @b{constant} Version_32 := 16#fa8db733#; - @b{pragma} Export (C, u00055, "system__val_lluS"); - u00056 : @b{constant} Version_32 := 16#27b600b2#; - @b{pragma} Export (C, u00056, "system__val_utilB"); - u00057 : @b{constant} Version_32 := 16#b187f27f#; - @b{pragma} Export (C, u00057, "system__val_utilS"); - u00058 : @b{constant} Version_32 := 16#d1060688#; - @b{pragma} Export (C, u00058, "system__case_utilB"); - u00059 : @b{constant} Version_32 := 16#392e2d56#; - @b{pragma} Export (C, u00059, "system__case_utilS"); - u00060 : @b{constant} Version_32 := 16#84a27f0d#; - @b{pragma} Export (C, u00060, "interfaces__c_streamsB"); - u00061 : @b{constant} Version_32 := 16#8bb5f2c0#; - @b{pragma} Export (C, u00061, "interfaces__c_streamsS"); - u00062 : @b{constant} Version_32 := 16#6db6928f#; - @b{pragma} Export (C, u00062, "system__crtlS"); - u00063 : @b{constant} Version_32 := 16#4e6a342b#; - @b{pragma} Export (C, u00063, "system__file_ioB"); - u00064 : @b{constant} Version_32 := 16#ba56a5e4#; - @b{pragma} Export (C, u00064, "system__file_ioS"); - u00065 : @b{constant} Version_32 := 16#b7ab275c#; - @b{pragma} Export (C, u00065, "ada__finalizationB"); - u00066 : @b{constant} Version_32 := 16#19f764ca#; - @b{pragma} Export (C, u00066, "ada__finalizationS"); - u00067 : @b{constant} Version_32 := 16#95817ed8#; - @b{pragma} Export (C, u00067, "system__finalization_rootB"); - u00068 : @b{constant} Version_32 := 16#52d53711#; - @b{pragma} Export (C, u00068, "system__finalization_rootS"); - u00069 : @b{constant} Version_32 := 16#769e25e6#; - @b{pragma} Export (C, u00069, "interfaces__cB"); - u00070 : @b{constant} Version_32 := 16#4a38bedb#; - @b{pragma} Export (C, u00070, "interfaces__cS"); - u00071 : @b{constant} Version_32 := 16#07e6ee66#; - @b{pragma} Export (C, u00071, "system__os_libB"); - u00072 : @b{constant} Version_32 := 16#d7b69782#; - @b{pragma} Export (C, u00072, "system__os_libS"); - u00073 : @b{constant} Version_32 := 16#1a817b8e#; - @b{pragma} Export (C, u00073, "system__stringsB"); - u00074 : @b{constant} Version_32 := 16#639855e7#; - @b{pragma} Export (C, u00074, "system__stringsS"); - u00075 : @b{constant} Version_32 := 16#e0b8de29#; - @b{pragma} Export (C, u00075, "system__file_control_blockS"); - u00076 : @b{constant} Version_32 := 16#b5b2aca1#; - @b{pragma} Export (C, u00076, "system__finalization_mastersB"); - u00077 : @b{constant} Version_32 := 16#69316dc1#; - @b{pragma} Export (C, u00077, "system__finalization_mastersS"); - u00078 : @b{constant} Version_32 := 16#57a37a42#; - @b{pragma} Export (C, u00078, "system__address_imageB"); - u00079 : @b{constant} Version_32 := 16#bccbd9bb#; - @b{pragma} Export (C, u00079, "system__address_imageS"); - u00080 : @b{constant} Version_32 := 16#7268f812#; - @b{pragma} Export (C, u00080, "system__img_boolB"); - u00081 : @b{constant} Version_32 := 16#e8fe356a#; - @b{pragma} Export (C, u00081, "system__img_boolS"); - u00082 : @b{constant} Version_32 := 16#d7aac20c#; - @b{pragma} Export (C, u00082, "system__ioB"); - u00083 : @b{constant} Version_32 := 16#8365b3ce#; - @b{pragma} Export (C, u00083, "system__ioS"); - u00084 : @b{constant} Version_32 := 16#6d4d969a#; - @b{pragma} Export (C, u00084, "system__storage_poolsB"); - u00085 : @b{constant} Version_32 := 16#e87cc305#; - @b{pragma} Export (C, u00085, "system__storage_poolsS"); - u00086 : @b{constant} Version_32 := 16#e34550ca#; - @b{pragma} Export (C, u00086, "system__pool_globalB"); - u00087 : @b{constant} Version_32 := 16#c88d2d16#; - @b{pragma} Export (C, u00087, "system__pool_globalS"); - u00088 : @b{constant} Version_32 := 16#9d39c675#; - @b{pragma} Export (C, u00088, "system__memoryB"); - u00089 : @b{constant} Version_32 := 16#445a22b5#; - @b{pragma} Export (C, u00089, "system__memoryS"); - u00090 : @b{constant} Version_32 := 16#6a859064#; - @b{pragma} Export (C, u00090, "system__storage_pools__subpoolsB"); - u00091 : @b{constant} Version_32 := 16#e3b008dc#; - @b{pragma} Export (C, u00091, "system__storage_pools__subpoolsS"); - u00092 : @b{constant} Version_32 := 16#63f11652#; - @b{pragma} Export (C, u00092, "system__storage_pools__subpools__finalizationB"); - u00093 : @b{constant} Version_32 := 16#fe2f4b3a#; - @b{pragma} Export (C, u00093, "system__storage_pools__subpools__finalizationS"); + type Version_32 is mod 2 ** 32; + u00001 : constant Version_32 := 16#8ad6e54a#; + pragma Export (C, u00001, "helloB"); + u00002 : constant Version_32 := 16#fbff4c67#; + pragma Export (C, u00002, "system__standard_libraryB"); + u00003 : constant Version_32 := 16#1ec6fd90#; + pragma Export (C, u00003, "system__standard_libraryS"); + u00004 : constant Version_32 := 16#3ffc8e18#; + pragma Export (C, u00004, "adaS"); + u00005 : constant Version_32 := 16#28f088c2#; + pragma Export (C, u00005, "ada__text_ioB"); + u00006 : constant Version_32 := 16#f372c8ac#; + pragma Export (C, u00006, "ada__text_ioS"); + u00007 : constant Version_32 := 16#2c143749#; + pragma Export (C, u00007, "ada__exceptionsB"); + u00008 : constant Version_32 := 16#f4f0cce8#; + pragma Export (C, u00008, "ada__exceptionsS"); + u00009 : constant Version_32 := 16#a46739c0#; + pragma Export (C, u00009, "ada__exceptions__last_chance_handlerB"); + u00010 : constant Version_32 := 16#3aac8c92#; + pragma Export (C, u00010, "ada__exceptions__last_chance_handlerS"); + u00011 : constant Version_32 := 16#1d274481#; + pragma Export (C, u00011, "systemS"); + u00012 : constant Version_32 := 16#a207fefe#; + pragma Export (C, u00012, "system__soft_linksB"); + u00013 : constant Version_32 := 16#467d9556#; + pragma Export (C, u00013, "system__soft_linksS"); + u00014 : constant Version_32 := 16#b01dad17#; + pragma Export (C, u00014, "system__parametersB"); + u00015 : constant Version_32 := 16#630d49fe#; + pragma Export (C, u00015, "system__parametersS"); + u00016 : constant Version_32 := 16#b19b6653#; + pragma Export (C, u00016, "system__secondary_stackB"); + u00017 : constant Version_32 := 16#b6468be8#; + pragma Export (C, u00017, "system__secondary_stackS"); + u00018 : constant Version_32 := 16#39a03df9#; + pragma Export (C, u00018, "system__storage_elementsB"); + u00019 : constant Version_32 := 16#30e40e85#; + pragma Export (C, u00019, "system__storage_elementsS"); + u00020 : constant Version_32 := 16#41837d1e#; + pragma Export (C, u00020, "system__stack_checkingB"); + u00021 : constant Version_32 := 16#93982f69#; + pragma Export (C, u00021, "system__stack_checkingS"); + u00022 : constant Version_32 := 16#393398c1#; + pragma Export (C, u00022, "system__exception_tableB"); + u00023 : constant Version_32 := 16#b33e2294#; + pragma Export (C, u00023, "system__exception_tableS"); + u00024 : constant Version_32 := 16#ce4af020#; + pragma Export (C, u00024, "system__exceptionsB"); + u00025 : constant Version_32 := 16#75442977#; + pragma Export (C, u00025, "system__exceptionsS"); + u00026 : constant Version_32 := 16#37d758f1#; + pragma Export (C, u00026, "system__exceptions__machineS"); + u00027 : constant Version_32 := 16#b895431d#; + pragma Export (C, u00027, "system__exceptions_debugB"); + u00028 : constant Version_32 := 16#aec55d3f#; + pragma Export (C, u00028, "system__exceptions_debugS"); + u00029 : constant Version_32 := 16#570325c8#; + pragma Export (C, u00029, "system__img_intB"); + u00030 : constant Version_32 := 16#1ffca443#; + pragma Export (C, u00030, "system__img_intS"); + u00031 : constant Version_32 := 16#b98c3e16#; + pragma Export (C, u00031, "system__tracebackB"); + u00032 : constant Version_32 := 16#831a9d5a#; + pragma Export (C, u00032, "system__tracebackS"); + u00033 : constant Version_32 := 16#9ed49525#; + pragma Export (C, u00033, "system__traceback_entriesB"); + u00034 : constant Version_32 := 16#1d7cb2f1#; + pragma Export (C, u00034, "system__traceback_entriesS"); + u00035 : constant Version_32 := 16#8c33a517#; + pragma Export (C, u00035, "system__wch_conB"); + u00036 : constant Version_32 := 16#065a6653#; + pragma Export (C, u00036, "system__wch_conS"); + u00037 : constant Version_32 := 16#9721e840#; + pragma Export (C, u00037, "system__wch_stwB"); + u00038 : constant Version_32 := 16#2b4b4a52#; + pragma Export (C, u00038, "system__wch_stwS"); + u00039 : constant Version_32 := 16#92b797cb#; + pragma Export (C, u00039, "system__wch_cnvB"); + u00040 : constant Version_32 := 16#09eddca0#; + pragma Export (C, u00040, "system__wch_cnvS"); + u00041 : constant Version_32 := 16#6033a23f#; + pragma Export (C, u00041, "interfacesS"); + u00042 : constant Version_32 := 16#ece6fdb6#; + pragma Export (C, u00042, "system__wch_jisB"); + u00043 : constant Version_32 := 16#899dc581#; + pragma Export (C, u00043, "system__wch_jisS"); + u00044 : constant Version_32 := 16#10558b11#; + pragma Export (C, u00044, "ada__streamsB"); + u00045 : constant Version_32 := 16#2e6701ab#; + pragma Export (C, u00045, "ada__streamsS"); + u00046 : constant Version_32 := 16#db5c917c#; + pragma Export (C, u00046, "ada__io_exceptionsS"); + u00047 : constant Version_32 := 16#12c8cd7d#; + pragma Export (C, u00047, "ada__tagsB"); + u00048 : constant Version_32 := 16#ce72c228#; + pragma Export (C, u00048, "ada__tagsS"); + u00049 : constant Version_32 := 16#c3335bfd#; + pragma Export (C, u00049, "system__htableB"); + u00050 : constant Version_32 := 16#99e5f76b#; + pragma Export (C, u00050, "system__htableS"); + u00051 : constant Version_32 := 16#089f5cd0#; + pragma Export (C, u00051, "system__string_hashB"); + u00052 : constant Version_32 := 16#3bbb9c15#; + pragma Export (C, u00052, "system__string_hashS"); + u00053 : constant Version_32 := 16#807fe041#; + pragma Export (C, u00053, "system__unsigned_typesS"); + u00054 : constant Version_32 := 16#d27be59e#; + pragma Export (C, u00054, "system__val_lluB"); + u00055 : constant Version_32 := 16#fa8db733#; + pragma Export (C, u00055, "system__val_lluS"); + u00056 : constant Version_32 := 16#27b600b2#; + pragma Export (C, u00056, "system__val_utilB"); + u00057 : constant Version_32 := 16#b187f27f#; + pragma Export (C, u00057, "system__val_utilS"); + u00058 : constant Version_32 := 16#d1060688#; + pragma Export (C, u00058, "system__case_utilB"); + u00059 : constant Version_32 := 16#392e2d56#; + pragma Export (C, u00059, "system__case_utilS"); + u00060 : constant Version_32 := 16#84a27f0d#; + pragma Export (C, u00060, "interfaces__c_streamsB"); + u00061 : constant Version_32 := 16#8bb5f2c0#; + pragma Export (C, u00061, "interfaces__c_streamsS"); + u00062 : constant Version_32 := 16#6db6928f#; + pragma Export (C, u00062, "system__crtlS"); + u00063 : constant Version_32 := 16#4e6a342b#; + pragma Export (C, u00063, "system__file_ioB"); + u00064 : constant Version_32 := 16#ba56a5e4#; + pragma Export (C, u00064, "system__file_ioS"); + u00065 : constant Version_32 := 16#b7ab275c#; + pragma Export (C, u00065, "ada__finalizationB"); + u00066 : constant Version_32 := 16#19f764ca#; + pragma Export (C, u00066, "ada__finalizationS"); + u00067 : constant Version_32 := 16#95817ed8#; + pragma Export (C, u00067, "system__finalization_rootB"); + u00068 : constant Version_32 := 16#52d53711#; + pragma Export (C, u00068, "system__finalization_rootS"); + u00069 : constant Version_32 := 16#769e25e6#; + pragma Export (C, u00069, "interfaces__cB"); + u00070 : constant Version_32 := 16#4a38bedb#; + pragma Export (C, u00070, "interfaces__cS"); + u00071 : constant Version_32 := 16#07e6ee66#; + pragma Export (C, u00071, "system__os_libB"); + u00072 : constant Version_32 := 16#d7b69782#; + pragma Export (C, u00072, "system__os_libS"); + u00073 : constant Version_32 := 16#1a817b8e#; + pragma Export (C, u00073, "system__stringsB"); + u00074 : constant Version_32 := 16#639855e7#; + pragma Export (C, u00074, "system__stringsS"); + u00075 : constant Version_32 := 16#e0b8de29#; + pragma Export (C, u00075, "system__file_control_blockS"); + u00076 : constant Version_32 := 16#b5b2aca1#; + pragma Export (C, u00076, "system__finalization_mastersB"); + u00077 : constant Version_32 := 16#69316dc1#; + pragma Export (C, u00077, "system__finalization_mastersS"); + u00078 : constant Version_32 := 16#57a37a42#; + pragma Export (C, u00078, "system__address_imageB"); + u00079 : constant Version_32 := 16#bccbd9bb#; + pragma Export (C, u00079, "system__address_imageS"); + u00080 : constant Version_32 := 16#7268f812#; + pragma Export (C, u00080, "system__img_boolB"); + u00081 : constant Version_32 := 16#e8fe356a#; + pragma Export (C, u00081, "system__img_boolS"); + u00082 : constant Version_32 := 16#d7aac20c#; + pragma Export (C, u00082, "system__ioB"); + u00083 : constant Version_32 := 16#8365b3ce#; + pragma Export (C, u00083, "system__ioS"); + u00084 : constant Version_32 := 16#6d4d969a#; + pragma Export (C, u00084, "system__storage_poolsB"); + u00085 : constant Version_32 := 16#e87cc305#; + pragma Export (C, u00085, "system__storage_poolsS"); + u00086 : constant Version_32 := 16#e34550ca#; + pragma Export (C, u00086, "system__pool_globalB"); + u00087 : constant Version_32 := 16#c88d2d16#; + pragma Export (C, u00087, "system__pool_globalS"); + u00088 : constant Version_32 := 16#9d39c675#; + pragma Export (C, u00088, "system__memoryB"); + u00089 : constant Version_32 := 16#445a22b5#; + pragma Export (C, u00089, "system__memoryS"); + u00090 : constant Version_32 := 16#6a859064#; + pragma Export (C, u00090, "system__storage_pools__subpoolsB"); + u00091 : constant Version_32 := 16#e3b008dc#; + pragma Export (C, u00091, "system__storage_pools__subpoolsS"); + u00092 : constant Version_32 := 16#63f11652#; + pragma Export (C, u00092, "system__storage_pools__subpools__finalizationB"); + u00093 : constant Version_32 := 16#fe2f4b3a#; + pragma Export (C, u00093, "system__storage_pools__subpools__finalizationS"); -- BEGIN ELABORATION ORDER -- ada%s @@ -22703,160 +32437,160 @@ Comments have been added for clarification purposes. -- hello%b -- END ELABORATION ORDER -@b{end} ada_main; +end ada_main; +@end example -@b{pragma} Ada_95; +@example +pragma Ada_95; -- The following source file name pragmas allow the generated file -- names to be unique for different main programs. They are needed -- since the package name will always be Ada_Main. -@b{pragma} Source_File_Name (ada_main, Spec_File_Name => "b~hello.ads"); -@b{pragma} Source_File_Name (ada_main, Body_File_Name => "b~hello.adb"); +pragma Source_File_Name (ada_main, Spec_File_Name => "b~hello.ads"); +pragma Source_File_Name (ada_main, Body_File_Name => "b~hello.adb"); -@b{pragma} Suppress (Overflow_Check); -@b{with} Ada.Exceptions; +pragma Suppress (Overflow_Check); +with Ada.Exceptions; -- Generated package body for Ada_Main starts here -@b{package} @b{body} ada_main @b{is} - @b{pragma} Warnings (Off); +package body ada_main is + pragma Warnings (Off); -- These values are reference counter associated to units which have -- been elaborated. It is also used to avoid elaborating the -- same unit twice. - E72 : Short_Integer; @b{pragma} Import (Ada, E72, "system__os_lib_E"); - E13 : Short_Integer; @b{pragma} Import (Ada, E13, "system__soft_links_E"); - E23 : Short_Integer; @b{pragma} Import (Ada, E23, "system__exception_table_E"); - E46 : Short_Integer; @b{pragma} Import (Ada, E46, "ada__io_exceptions_E"); - E48 : Short_Integer; @b{pragma} Import (Ada, E48, "ada__tags_E"); - E45 : Short_Integer; @b{pragma} Import (Ada, E45, "ada__streams_E"); - E70 : Short_Integer; @b{pragma} Import (Ada, E70, "interfaces__c_E"); - E25 : Short_Integer; @b{pragma} Import (Ada, E25, "system__exceptions_E"); - E68 : Short_Integer; @b{pragma} Import (Ada, E68, "system__finalization_root_E"); - E66 : Short_Integer; @b{pragma} Import (Ada, E66, "ada__finalization_E"); - E85 : Short_Integer; @b{pragma} Import (Ada, E85, "system__storage_pools_E"); - E77 : Short_Integer; @b{pragma} Import (Ada, E77, "system__finalization_masters_E"); - E91 : Short_Integer; @b{pragma} Import (Ada, E91, "system__storage_pools__subpools_E"); - E87 : Short_Integer; @b{pragma} Import (Ada, E87, "system__pool_global_E"); - E75 : Short_Integer; @b{pragma} Import (Ada, E75, "system__file_control_block_E"); - E64 : Short_Integer; @b{pragma} Import (Ada, E64, "system__file_io_E"); - E17 : Short_Integer; @b{pragma} Import (Ada, E17, "system__secondary_stack_E"); - E06 : Short_Integer; @b{pragma} Import (Ada, E06, "ada__text_io_E"); - - Local_Priority_Specific_Dispatching : @b{constant} String := ""; - Local_Interrupt_States : @b{constant} String := ""; + E72 : Short_Integer; pragma Import (Ada, E72, "system__os_lib_E"); + E13 : Short_Integer; pragma Import (Ada, E13, "system__soft_links_E"); + E23 : Short_Integer; pragma Import (Ada, E23, "system__exception_table_E"); + E46 : Short_Integer; pragma Import (Ada, E46, "ada__io_exceptions_E"); + E48 : Short_Integer; pragma Import (Ada, E48, "ada__tags_E"); + E45 : Short_Integer; pragma Import (Ada, E45, "ada__streams_E"); + E70 : Short_Integer; pragma Import (Ada, E70, "interfaces__c_E"); + E25 : Short_Integer; pragma Import (Ada, E25, "system__exceptions_E"); + E68 : Short_Integer; pragma Import (Ada, E68, "system__finalization_root_E"); + E66 : Short_Integer; pragma Import (Ada, E66, "ada__finalization_E"); + E85 : Short_Integer; pragma Import (Ada, E85, "system__storage_pools_E"); + E77 : Short_Integer; pragma Import (Ada, E77, "system__finalization_masters_E"); + E91 : Short_Integer; pragma Import (Ada, E91, "system__storage_pools__subpools_E"); + E87 : Short_Integer; pragma Import (Ada, E87, "system__pool_global_E"); + E75 : Short_Integer; pragma Import (Ada, E75, "system__file_control_block_E"); + E64 : Short_Integer; pragma Import (Ada, E64, "system__file_io_E"); + E17 : Short_Integer; pragma Import (Ada, E17, "system__secondary_stack_E"); + E06 : Short_Integer; pragma Import (Ada, E06, "ada__text_io_E"); + + Local_Priority_Specific_Dispatching : constant String := ""; + Local_Interrupt_States : constant String := ""; Is_Elaborated : Boolean := False; -@findex finalize_library - @b{procedure} finalize_library @b{is} - @b{begin} + procedure finalize_library is + begin E06 := E06 - 1; - @b{declare} - @b{procedure} F1; - @b{pragma} Import (Ada, F1, "ada__text_io__finalize_spec"); - @b{begin} + declare + procedure F1; + pragma Import (Ada, F1, "ada__text_io__finalize_spec"); + begin F1; - @b{end}; + end; E77 := E77 - 1; E91 := E91 - 1; - @b{declare} - @b{procedure} F2; - @b{pragma} Import (Ada, F2, "system__file_io__finalize_body"); - @b{begin} + declare + procedure F2; + pragma Import (Ada, F2, "system__file_io__finalize_body"); + begin E64 := E64 - 1; F2; - @b{end}; - @b{declare} - @b{procedure} F3; - @b{pragma} Import (Ada, F3, "system__file_control_block__finalize_spec"); - @b{begin} + end; + declare + procedure F3; + pragma Import (Ada, F3, "system__file_control_block__finalize_spec"); + begin E75 := E75 - 1; F3; - @b{end}; + end; E87 := E87 - 1; - @b{declare} - @b{procedure} F4; - @b{pragma} Import (Ada, F4, "system__pool_global__finalize_spec"); - @b{begin} + declare + procedure F4; + pragma Import (Ada, F4, "system__pool_global__finalize_spec"); + begin F4; - @b{end}; - @b{declare} - @b{procedure} F5; - @b{pragma} Import (Ada, F5, "system__storage_pools__subpools__finalize_spec"); - @b{begin} + end; + declare + procedure F5; + pragma Import (Ada, F5, "system__storage_pools__subpools__finalize_spec"); + begin F5; - @b{end}; - @b{declare} - @b{procedure} F6; - @b{pragma} Import (Ada, F6, "system__finalization_masters__finalize_spec"); - @b{begin} + end; + declare + procedure F6; + pragma Import (Ada, F6, "system__finalization_masters__finalize_spec"); + begin F6; - @b{end}; - @b{declare} - @b{procedure} Reraise_Library_Exception_If_Any; - @b{pragma} Import (Ada, Reraise_Library_Exception_If_Any, "__gnat_reraise_library_exception_if_any"); - @b{begin} + end; + declare + procedure Reraise_Library_Exception_If_Any; + pragma Import (Ada, Reraise_Library_Exception_If_Any, "__gnat_reraise_library_exception_if_any"); + begin Reraise_Library_Exception_If_Any; - @b{end}; - @b{end} finalize_library; + end; + end finalize_library; ------------- -- adainit -- ------------- -@findex adainit - @b{procedure} adainit @b{is} + procedure adainit is Main_Priority : Integer; - @b{pragma} Import (C, Main_Priority, "__gl_main_priority"); + pragma Import (C, Main_Priority, "__gl_main_priority"); Time_Slice_Value : Integer; - @b{pragma} Import (C, Time_Slice_Value, "__gl_time_slice_val"); + pragma Import (C, Time_Slice_Value, "__gl_time_slice_val"); WC_Encoding : Character; - @b{pragma} Import (C, WC_Encoding, "__gl_wc_encoding"); + pragma Import (C, WC_Encoding, "__gl_wc_encoding"); Locking_Policy : Character; pragma Import (C, Locking_Policy, "__gl_locking_policy"); Queuing_Policy : Character; - @b{pragma} Import (C, Queuing_Policy, "__gl_queuing_policy"); + pragma Import (C, Queuing_Policy, "__gl_queuing_policy"); Task_Dispatching_Policy : Character; - @b{pragma} Import (C, Task_Dispatching_Policy, "__gl_task_dispatching_policy"); + pragma Import (C, Task_Dispatching_Policy, "__gl_task_dispatching_policy"); Priority_Specific_Dispatching : System.Address; - @b{pragma} Import (C, Priority_Specific_Dispatching, "__gl_priority_specific_dispatching"); + pragma Import (C, Priority_Specific_Dispatching, "__gl_priority_specific_dispatching"); Num_Specific_Dispatching : Integer; - @b{pragma} Import (C, Num_Specific_Dispatching, "__gl_num_specific_dispatching"); + pragma Import (C, Num_Specific_Dispatching, "__gl_num_specific_dispatching"); Main_CPU : Integer; - @b{pragma} Import (C, Main_CPU, "__gl_main_cpu"); + pragma Import (C, Main_CPU, "__gl_main_cpu"); Interrupt_States : System.Address; - @b{pragma} Import (C, Interrupt_States, "__gl_interrupt_states"); + pragma Import (C, Interrupt_States, "__gl_interrupt_states"); Num_Interrupt_States : Integer; - @b{pragma} Import (C, Num_Interrupt_States, "__gl_num_interrupt_states"); + pragma Import (C, Num_Interrupt_States, "__gl_num_interrupt_states"); Unreserve_All_Interrupts : Integer; - @b{pragma} Import (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts"); + pragma Import (C, Unreserve_All_Interrupts, "__gl_unreserve_all_interrupts"); Detect_Blocking : Integer; - @b{pragma} Import (C, Detect_Blocking, "__gl_detect_blocking"); + pragma Import (C, Detect_Blocking, "__gl_detect_blocking"); Default_Stack_Size : Integer; - @b{pragma} Import (C, Default_Stack_Size, "__gl_default_stack_size"); + pragma Import (C, Default_Stack_Size, "__gl_default_stack_size"); Leap_Seconds_Support : Integer; - @b{pragma} Import (C, Leap_Seconds_Support, "__gl_leap_seconds_support"); + pragma Import (C, Leap_Seconds_Support, "__gl_leap_seconds_support"); procedure Runtime_Initialize; - @b{pragma} Import (C, Runtime_Initialize, "__gnat_runtime_initialize"); + pragma Import (C, Runtime_Initialize, "__gnat_runtime_initialize"); Finalize_Library_Objects : No_Param_Proc; - @b{pragma} Import (C, Finalize_Library_Objects, "__gnat_finalize_library_objects"); + pragma Import (C, Finalize_Library_Objects, "__gnat_finalize_library_objects"); -- Start of processing for adainit - @b{begin} + begin -- Record various information for this partition. The values -- are derived by the binder from information stored in the ali -- files by the compiler. - @b{if} Is_Elaborated @b{then} - @b{return}; - @b{end if}; + if Is_Elaborated then + return; + end if; Is_Elaborated := True; Main_Priority := -1; Time_Slice_Value := -1; @@ -22925,38 +32659,37 @@ Comments have been added for clarification purposes. Ada.Text_Io'Elab_Spec; Ada.Text_Io'Elab_Body; E06 := E06 + 1; - @b{end} adainit; + end adainit; -------------- -- adafinal -- -------------- -@findex adafinal - @b{procedure} adafinal @b{is} - @b{procedure} s_stalib_adafinal; - @b{pragma} Import (C, s_stalib_adafinal, "system__standard_library__adafinal"); + procedure adafinal is + procedure s_stalib_adafinal; + pragma Import (C, s_stalib_adafinal, "system__standard_library__adafinal"); - @b{procedure} Runtime_Finalize; - @b{pragma} Import (C, Runtime_Finalize, "__gnat_runtime_finalize"); + procedure Runtime_Finalize; + pragma Import (C, Runtime_Finalize, "__gnat_runtime_finalize"); - @b{begin} - @b{if not} Is_Elaborated @b{then} - @b{return}; - @b{end if}; + begin + if not Is_Elaborated then + return; + end if; Is_Elaborated := False; Runtime_Finalize; s_stalib_adafinal; - @b{end} adafinal; + end adafinal; -- We get to the main program of the partition by using -- pragma Import because if we try to with the unit and -- call it Ada style, then not only do we waste time -- recompiling it, but also, we don't really know the right - -- switches (e.g.@: identifier character set) to be used + -- switches (e.g.@@: identifier character set) to be used -- to compile it. - @b{procedure} Ada_Main_Program; - @b{pragma} Import (Ada, Ada_Main_Program, "_ada_hello"); + procedure Ada_Main_Program; + pragma Import (Ada, Ada_Main_Program, "_ada_hello"); ---------- -- main -- @@ -22967,22 +32700,20 @@ Comments have been added for clarification purposes. -- are the argument count, argument values and environment -- pointer. -@findex Main Program - @b{function} main + function main (argc : Integer; argv : System.Address; envp : System.Address) - @b{return} Integer - @b{is} + return Integer + is -- The initialize routine performs low level system -- initialization using a standard library routine which -- sets up signal handling and performs any other -- required setup. The routine can be found in file -- a-init.c. -@findex __gnat_initialize - @b{procedure} initialize; - @b{pragma} Import (C, initialize, "__gnat_initialize"); + procedure initialize; + pragma Import (C, initialize, "__gnat_initialize"); -- The finalize routine performs low level system -- finalization using a standard library routine. The @@ -22990,20 +32721,19 @@ Comments have been added for clarification purposes. -- distribution is a dummy routine that does nothing, so -- really this is a hook for special user finalization. -@findex __gnat_finalize - @b{procedure} finalize; - @b{pragma} Import (C, finalize, "__gnat_finalize"); + procedure finalize; + pragma Import (C, finalize, "__gnat_finalize"); -- The following is to initialize the SEH exceptions - SEH : @b{aliased array} (1 .. 2) of Integer; + SEH : aliased array (1 .. 2) of Integer; Ensure_Reference : aliased System.Address := Ada_Main_Program_Name'Address; - @b{pragma} Volatile (Ensure_Reference); + pragma Volatile (Ensure_Reference); -- Start of processing for main - @b{begin} + begin -- Save global variables gnat_argc := argc; @@ -23031,8 +32761,8 @@ Comments have been added for clarification purposes. Finalize; -- Return the proper exit status - @b{return} (gnat_exit_status); - @b{end}; + return (gnat_exit_status); + end; -- This section is entirely comments, so it has no effect on the -- compilation of the Ada_Main package. It provides the list of @@ -23046,7 +32776,6 @@ Comments have been added for clarification purposes. -- The exact file names will of course depend on the environment, -- host/target and location of files on the host system. -@findex Object file list -- BEGIN Object file/option list -- ./hello.o -- -L./ @@ -23054,86 +32783,100 @@ Comments have been added for clarification purposes. -- /usr/local/gnat/lib/gcc-lib/i686-pc-linux-gnu/2.8.1/adalib/libgnat.a -- END Object file/option list -@b{end} ada_main; -@end smallexample +end ada_main; +@end example -@noindent The Ada code in the above example is exactly what is generated by the binder. We have added comments to more clearly indicate the function -of each part of the generated @code{Ada_Main} package. +of each part of the generated @cite{Ada_Main} package. The code is standard Ada in all respects, and can be processed by any tools that handle Ada. In particular, it is possible to use the debugger -in Ada mode to debug the generated @code{Ada_Main} package. For example, +in Ada mode to debug the generated @cite{Ada_Main} package. For example, suppose that for reasons that you do not understand, your program is crashing -during elaboration of the body of @code{Ada.Text_IO}. To locate this bug, +during elaboration of the body of @cite{Ada.Text_IO}. To locate this bug, you can place a breakpoint on the call: -@smallexample @c ada +@quotation + +@example Ada.Text_Io'Elab_Body; -@end smallexample +@end example +@end quotation -@noindent and trace the elaboration routine for this package to find out where the problem might be (more usually of course you would be debugging elaboration code in your own application). -@node Elaboration Order Handling in GNAT -@appendix Elaboration Order Handling in GNAT -@cindex Order of elaboration -@cindex Elaboration control +@c -- Example: A |withing| unit has a |with| clause, it |withs| a |withed| unit + +@node Elaboration Order Handling in GNAT,Inline Assembler,Example of Binder Output File,Top +@anchor{gnat_ugn/elaboration_order_handling_in_gnat elaboration-order-handling-in-gnat}@anchor{11}@anchor{gnat_ugn/elaboration_order_handling_in_gnat doc}@anchor{2ae}@anchor{gnat_ugn/elaboration_order_handling_in_gnat id1}@anchor{2af} +@chapter Elaboration Order Handling in GNAT -@menu -* Elaboration Code:: -* Checking the Elaboration Order:: -* Controlling the Elaboration Order:: -* Controlling Elaboration in GNAT - Internal Calls:: -* Controlling Elaboration in GNAT - External Calls:: -* Default Behavior in GNAT - Ensuring Safety:: -* Treatment of Pragma Elaborate:: -* Elaboration Issues for Library Tasks:: -* Mixing Elaboration Models:: -* What to Do If the Default Elaboration Behavior Fails:: -* Elaboration for Indirect Calls:: -* Summary of Procedures for Elaboration Control:: -* Other Elaboration Order Considerations:: -* Determining the Chosen Elaboration Order:: -@end menu -@noindent -This chapter describes the handling of elaboration code in Ada and +@geindex Order of elaboration + +@geindex Elaboration control + +This appendix describes the handling of elaboration code in Ada and in GNAT, and discusses how the order of elaboration of program units can be controlled in GNAT, either automatically or with explicit programming features. -@node Elaboration Code +@menu +* Elaboration Code:: +* Checking the Elaboration Order:: +* Controlling the Elaboration Order:: +* Controlling Elaboration in GNAT - Internal Calls:: +* Controlling Elaboration in GNAT - External Calls:: +* Default Behavior in GNAT - Ensuring Safety:: +* Treatment of Pragma Elaborate:: +* Elaboration Issues for Library Tasks:: +* Mixing Elaboration Models:: +* What to Do If the Default Elaboration Behavior Fails:: +* Elaboration for Indirect Calls:: +* Summary of Procedures for Elaboration Control:: +* Other Elaboration Order Considerations:: +* Determining the Chosen Elaboration Order:: + +@end menu + +@node Elaboration Code,Checking the Elaboration Order,,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat elaboration-code}@anchor{2b0}@anchor{gnat_ugn/elaboration_order_handling_in_gnat id2}@anchor{2b1} @section Elaboration Code -@noindent + Ada provides rather general mechanisms for executing code at elaboration time, that is to say before the main program starts executing. Such code arises in three contexts: -@table @asis -@item Initializers for variables. + +@itemize * + +@item +@emph{Initializers for variables} + Variables declared at the library level, in package specs or bodies, can require initialization that is performed at elaboration time, as in: -@smallexample @c ada -@cartouche + +@example Sqrt_Half : Float := Sqrt (0.5); -@end cartouche -@end smallexample +@end example -@item Package initialization code -Code in a @code{BEGIN-END} section at the outer level of a package body is +@item +@emph{Package initialization code} + +Code in a @cite{BEGIN-END} section at the outer level of a package body is executed as part of the package body elaboration code. -@item Library level task allocators +@item +@emph{Library level task allocators} + Tasks that are declared using task allocators at the library level start executing immediately and hence can execute at elaboration time. -@end table +@end itemize -@noindent Subprogram calls are possible in any of these contexts, which means that any arbitrary part of the program may be executed as part of the elaboration code. It is even possible to write a program which does all its work at @@ -23146,29 +32889,24 @@ we have to be sure that it is executed in an appropriate order. What we have is a series of elaboration code sections, potentially one section for each unit in the program. It is important that these execute in the correct order. Correctness here means that, taking the above -example of the declaration of @code{Sqrt_Half}, +example of the declaration of @cite{Sqrt_Half}, if some other piece of -elaboration code references @code{Sqrt_Half}, +elaboration code references @cite{Sqrt_Half}, then it must run after the section of elaboration code that contains the declaration of -@code{Sqrt_Half}. +@cite{Sqrt_Half}. There would never be any order of elaboration problem if we made a rule -that whenever you @code{with} a unit, you must elaborate both the spec and body -of that unit before elaborating the unit doing the @code{with}'ing: +that whenever you @emph{with} a unit, you must elaborate both the spec and body +of that unit before elaborating the unit doing the @emph{with}ing: -@smallexample @c ada -@group -@cartouche -@b{with} Unit_1; -@b{package} Unit_2 @b{is} @dots{} -@end cartouche -@end group -@end smallexample +@example +with Unit_1; +package Unit_2 is ... +@end example -@noindent -would require that both the body and spec of @code{Unit_1} be elaborated -before the spec of @code{Unit_2}. However, a rule like that would be far too +would require that both the body and spec of @cite{Unit_1} be elaborated +before the spec of @cite{Unit_2}. However, a rule like that would be far too restrictive. In particular, it would make it impossible to have routines in separate packages that were mutually recursive. @@ -23177,112 +32915,91 @@ elaboration code and determine an appropriate correct order of elaboration, but in the general case, this is not possible. Consider the following example. -In the body of @code{Unit_1}, we have a procedure @code{Func_1} +In the body of @cite{Unit_1}, we have a procedure @cite{Func_1} that references -the variable @code{Sqrt_1}, which is declared in the elaboration code -of the body of @code{Unit_1}: +the variable @cite{Sqrt_1}, which is declared in the elaboration code +of the body of @cite{Unit_1}: -@smallexample @c ada -@cartouche +@example Sqrt_1 : Float := Sqrt (0.1); -@end cartouche -@end smallexample +@end example -@noindent -The elaboration code of the body of @code{Unit_1} also contains: +The elaboration code of the body of @cite{Unit_1} also contains: -@smallexample @c ada -@group -@cartouche -@b{if} expression_1 = 1 @b{then} +@example +if expression_1 = 1 then Q := Unit_2.Func_2; -@b{end} @b{if}; -@end cartouche -@end group -@end smallexample +end if; +@end example -@noindent -@code{Unit_2} is exactly parallel, -it has a procedure @code{Func_2} that references -the variable @code{Sqrt_2}, which is declared in the elaboration code of -the body @code{Unit_2}: +@cite{Unit_2} is exactly parallel, +it has a procedure @cite{Func_2} that references +the variable @cite{Sqrt_2}, which is declared in the elaboration code of +the body @cite{Unit_2}: -@smallexample @c ada -@cartouche +@example Sqrt_2 : Float := Sqrt (0.1); -@end cartouche -@end smallexample +@end example -@noindent -The elaboration code of the body of @code{Unit_2} also contains: +The elaboration code of the body of @cite{Unit_2} also contains: -@smallexample @c ada -@group -@cartouche -@b{if} expression_2 = 2 @b{then} +@example +if expression_2 = 2 then Q := Unit_1.Func_1; -@b{end} @b{if}; -@end cartouche -@end group -@end smallexample +end if; +@end example -@noindent Now the question is, which of the following orders of elaboration is acceptable: -@smallexample -@group +@example Spec of Unit_1 Spec of Unit_2 Body of Unit_1 Body of Unit_2 -@end group -@end smallexample +@end example -@noindent or -@smallexample -@group +@example Spec of Unit_2 Spec of Unit_1 Body of Unit_2 Body of Unit_1 -@end group -@end smallexample +@end example -@noindent If you carefully analyze the flow here, you will see that you cannot tell at compile time the answer to this question. -If @code{expression_1} is not equal to 1, -and @code{expression_2} is not equal to 2, +If @cite{expression_1} is not equal to 1, +and @cite{expression_2} is not equal to 2, then either order is acceptable, because neither of the function calls is executed. If both tests evaluate to true, then neither order is acceptable and in fact there is no correct order. If one of the two expressions is true, and the other is false, then one of the above orders is correct, and the other is incorrect. For example, -if @code{expression_1} /= 1 and @code{expression_2} = 2, -then the call to @code{Func_1} -will occur, but not the call to @code{Func_2.} +if @cite{expression_1} /= 1 and @cite{expression_2} = 2, +then the call to @cite{Func_1} +will occur, but not the call to @cite{Func_2.} This means that it is essential -to elaborate the body of @code{Unit_1} before -the body of @code{Unit_2}, so the first +to elaborate the body of @cite{Unit_1} before +the body of @cite{Unit_2}, so the first order of elaboration is correct and the second is wrong. -By making @code{expression_1} and @code{expression_2} +By making @cite{expression_1} and @cite{expression_2} depend on input data, or perhaps the time of day, we can make it impossible for the compiler or binder to figure out which of these expressions will be true, and hence it is impossible to guarantee a safe order of elaboration at run time. -@node Checking the Elaboration Order +@node Checking the Elaboration Order,Controlling the Elaboration Order,Elaboration Code,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat checking-the-elaboration-order}@anchor{2b2}@anchor{gnat_ugn/elaboration_order_handling_in_gnat id3}@anchor{2b3} @section Checking the Elaboration Order -@noindent + In some languages that involve the same kind of elaboration problems, -e.g.@: Java and C++, the programmer is expected to worry about these -ordering problems himself, and it is common to +e.g., Java and C++, the programmer needs to take these +ordering problems into account, and it is common to write a program in which an incorrect elaboration order gives surprising results, because it references variables before they are initialized. @@ -23290,25 +33007,40 @@ Ada is designed to be a safe language, and a programmer-beware approach is clearly not sufficient. Consequently, the language provides three lines of defense: -@table @asis -@item Standard rules + +@itemize * + +@item +@emph{Standard rules} + Some standard rules restrict the possible choice of elaboration -order. In particular, if you @code{with} a unit, then its spec is always -elaborated before the unit doing the @code{with}. Similarly, a parent +order. In particular, if you @emph{with} a unit, then its spec is always +elaborated before the unit doing the @emph{with}. Similarly, a parent spec is always elaborated before the child spec, and finally a spec is always elaborated before its corresponding body. +@end itemize + +@geindex Elaboration checks + +@geindex Checks +@geindex elaboration + + +@itemize * + +@item +@emph{Dynamic elaboration checks} -@item Dynamic elaboration checks -@cindex Elaboration checks -@cindex Checks, elaboration Dynamic checks are made at run time, so that if some entity is accessed before it is elaborated (typically by means of a subprogram call) -then the exception (@code{Program_Error}) is raised. +then the exception (@cite{Program_Error}) is raised. + +@item +@emph{Elaboration control} -@item Elaboration control Facilities are provided for the programmer to specify the desired order of elaboration. -@end table +@end itemize Let's look at these facilities in more detail. First, the rules for dynamic checking. One possible rule would be simply to say that the @@ -23318,23 +33050,28 @@ expensive checks on every variable reference. Instead Ada has two rules which are a little more restrictive, but easier to check, and easier to state: -@table @asis -@item Restrictions on calls + +@itemize * + +@item +@emph{Restrictions on calls} + A subprogram can only be called at elaboration time if its body has been elaborated. The rules for elaboration given above guarantee that the spec of the subprogram has been elaborated before the call, but not the body. If this rule is violated, then the -exception @code{Program_Error} is raised. +exception @cite{Program_Error} is raised. + +@item +@emph{Restrictions on instantiations} -@item Restrictions on instantiations A generic unit can only be instantiated if the body of the generic unit has been elaborated. Again, the rules for elaboration given above guarantee that the spec of the generic unit has been elaborated before the instantiation, but not the body. If this rule is -violated, then the exception @code{Program_Error} is raised. -@end table +violated, then the exception @cite{Program_Error} is raised. +@end itemize -@noindent The idea is that if the body has been elaborated, then any variables it references must have been elaborated; by checking for the body being elaborated we guarantee that none of its references causes any @@ -23348,23 +33085,24 @@ A plausible implementation can be described as follows. A Boolean variable is associated with each subprogram and each generic unit. This variable is initialized to False, and is set to True at the point body is elaborated. Every call or instantiation checks the -variable, and raises @code{Program_Error} if the variable is False. +variable, and raises @cite{Program_Error} if the variable is False. Note that one might think that it would be good enough to have one Boolean variable for each package, but that would not deal with cases of trying to call a body in the same package as the call that has not been elaborated yet. Of course a compiler may be able to do enough analysis to optimize away -some of the Boolean variables as unnecessary, and @code{GNAT} indeed +some of the Boolean variables as unnecessary, and @cite{GNAT} indeed does such optimizations, but still the easiest conceptual model is to think of there being one variable per subprogram. -@node Controlling the Elaboration Order +@node Controlling the Elaboration Order,Controlling Elaboration in GNAT - Internal Calls,Checking the Elaboration Order,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id4}@anchor{2b4}@anchor{gnat_ugn/elaboration_order_handling_in_gnat controlling-the-elaboration-order}@anchor{2b5} @section Controlling the Elaboration Order -@noindent + In the previous section we discussed the rules in Ada which ensure -that @code{Program_Error} is raised if an incorrect elaboration order is +that @cite{Program_Error} is raised if an incorrect elaboration order is chosen. This prevents erroneous executions, but we need mechanisms to specify a correct execution and avoid the exception altogether. To achieve this, Ada provides a number of features for controlling @@ -23373,170 +33111,189 @@ the order of elaboration. We discuss these features in this section. First, there are several ways of indicating to the compiler that a given unit has no elaboration problems: -@table @asis -@item packages that do not require a body + +@itemize * + +@item +@emph{packages that do not require a body} + A library package that does not require a body does not permit a body (this rule was introduced in Ada 95). Thus if we have a such a package, as in: -@smallexample @c ada -@group -@cartouche -@b{package} Definitions @b{is} - @b{generic} - @b{type} m @b{is} @b{new} integer; - @b{package} Subp @b{is} - @b{type} a @b{is} @b{array} (1 .. 10) @b{of} m; - @b{type} b @b{is} @b{array} (1 .. 20) @b{of} m; - @b{end} Subp; -@b{end} Definitions; -@end cartouche -@end group -@end smallexample - -@noindent -A package that @code{with}'s @code{Definitions} may safely instantiate -@code{Definitions.Subp} because the compiler can determine that there +@example +package Definitions is + generic + type m is new integer; + package Subp is + type a is array (1 .. 10) of m; + type b is array (1 .. 20) of m; + end Subp; +end Definitions; +@end example + +A package that @emph{with}s @cite{Definitions} may safely instantiate +@cite{Definitions.Subp} because the compiler can determine that there definitely is no package body to worry about in this case +@end itemize + +@geindex pragma Pure + + +@itemize * -@item pragma Pure -@cindex pragma Pure -@findex Pure -Places sufficient restrictions on a unit to guarantee that +@item +@emph{pragma Pure} + +This pragma places sufficient restrictions on a unit to guarantee that no call to any subprogram in the unit can result in an elaboration problem. This means that the compiler does not need to worry about the point of elaboration of such units, and in particular, does not need to check any calls to any subprograms in this unit. +@end itemize + +@geindex pragma Preelaborate + + +@itemize * + +@item +@emph{pragma Preelaborate} -@item pragma Preelaborate -@findex Preelaborate -@cindex pragma Preelaborate This pragma places slightly less stringent restrictions on a unit than does pragma Pure, but these restrictions are still sufficient to ensure that there are no elaboration problems with any calls to the unit. +@end itemize + +@geindex pragma Elaborate_Body + + +@itemize * + +@item +@emph{pragma Elaborate_Body} -@item pragma Elaborate_Body -@findex Elaborate_Body -@cindex pragma Elaborate_Body This pragma requires that the body of a unit be elaborated immediately -after its spec. Suppose a unit @code{A} has such a pragma, -and unit @code{B} does -a @code{with} of unit @code{A}. Recall that the standard rules require -the spec of unit @code{A} -to be elaborated before the @code{with}'ing unit; given the pragma in -@code{A}, we also know that the body of @code{A} -will be elaborated before @code{B}, so -that calls to @code{A} are safe and do not need a check. -@end table - -@noindent -Note that, -unlike pragma @code{Pure} and pragma @code{Preelaborate}, -the use of -@code{Elaborate_Body} does not guarantee that the program is +after its spec. Suppose a unit @cite{A} has such a pragma, +and unit @cite{B} does +a @emph{with} of unit @cite{A}. Recall that the standard rules require +the spec of unit @cite{A} +to be elaborated before the @emph{with}ing unit; given the pragma in +@cite{A}, we also know that the body of @cite{A} +will be elaborated before @cite{B}, so +that calls to @cite{A} are safe and do not need a check. + +Note that, unlike pragma @cite{Pure} and pragma @cite{Preelaborate}, +the use of @cite{Elaborate_Body} does not guarantee that the program is free of elaboration problems, because it may not be possible to satisfy the requested elaboration order. -Let's go back to the example with @code{Unit_1} and @code{Unit_2}. -If a programmer -marks @code{Unit_1} as @code{Elaborate_Body}, -and not @code{Unit_2,} then the order of +Let's go back to the example with @cite{Unit_1} and @cite{Unit_2}. +If a programmer marks @cite{Unit_1} as @cite{Elaborate_Body}, +and not @cite{Unit_2@comma{}} then the order of elaboration will be: -@smallexample -@group +@example Spec of Unit_2 Spec of Unit_1 Body of Unit_1 Body of Unit_2 -@end group -@end smallexample +@end example -@noindent -Now that means that the call to @code{Func_1} in @code{Unit_2} +Now that means that the call to @cite{Func_1} in @cite{Unit_2} need not be checked, -it must be safe. But the call to @code{Func_2} in -@code{Unit_1} may still fail if -@code{Expression_1} is equal to 1, +it must be safe. But the call to @cite{Func_2} in +@cite{Unit_1} may still fail if +@cite{Expression_1} is equal to 1, and the programmer must still take responsibility for this not being the case. -If all units carry a pragma @code{Elaborate_Body}, then all problems are +If all units carry a pragma @cite{Elaborate_Body}, then all problems are eliminated, except for calls entirely within a body, which are in any case fully under programmer control. However, using the pragma everywhere is not always possible. -In particular, for our @code{Unit_1}/@code{Unit_2} example, if -we marked both of them as having pragma @code{Elaborate_Body}, then +In particular, for our @cite{Unit_1}/@cite{Unit_2} example, if +we marked both of them as having pragma @cite{Elaborate_Body}, then clearly there would be no possible elaboration order. +@end itemize The above pragmas allow a server to guarantee safe use by clients, and clearly this is the preferable approach. Consequently a good rule -is to mark units as @code{Pure} or @code{Preelaborate} if possible, +is to mark units as @cite{Pure} or @cite{Preelaborate} if possible, and if this is not possible, -mark them as @code{Elaborate_Body} if possible. +mark them as @cite{Elaborate_Body} if possible. As we have seen, there are situations where neither of these three pragmas can be used. So we also provide methods for clients to control the order of elaboration of the servers on which they depend: -@table @asis -@item pragma Elaborate (unit) -@findex Elaborate -@cindex pragma Elaborate -This pragma is placed in the context clause, after a @code{with} clause, +@geindex pragma Elaborate + + +@itemize * + +@item +@emph{pragma Elaborate (unit)} + +This pragma is placed in the context clause, after a @emph{with} clause, and it requires that the body of the named unit be elaborated before the unit in which the pragma occurs. The idea is to use this pragma if the current unit calls at elaboration time, directly or indirectly, some subprogram in the named unit. +@end itemize + +@geindex pragma Elaborate_All + + +@itemize * + +@item +@emph{pragma Elaborate_All (unit)} -@item pragma Elaborate_All (unit) -@findex Elaborate_All -@cindex pragma Elaborate_All This is a stronger version of the Elaborate pragma. Consider the following example: -@smallexample -Unit A @code{with}'s unit B and calls B.Func in elab code -Unit B @code{with}'s unit C, and B.Func calls C.Func -@end smallexample - -@noindent -Now if we put a pragma @code{Elaborate (B)} -in unit @code{A}, this ensures that the -body of @code{B} is elaborated before the call, but not the -body of @code{C}, so -the call to @code{C.Func} could still cause @code{Program_Error} to +@example +Unit A |withs| unit B and calls B.Func in elab code +Unit B |withs| unit C, and B.Func calls C.Func +@end example + +Now if we put a pragma @cite{Elaborate (B)} +in unit @cite{A}, this ensures that the +body of @cite{B} is elaborated before the call, but not the +body of @cite{C}, so +the call to @cite{C.Func} could still cause @cite{Program_Error} to be raised. -The effect of a pragma @code{Elaborate_All} is stronger, it requires +The effect of a pragma @cite{Elaborate_All} is stronger, it requires not only that the body of the named unit be elaborated before the -unit doing the @code{with}, but also the bodies of all units that the -named unit uses, following @code{with} links transitively. For example, -if we put a pragma @code{Elaborate_All (B)} in unit @code{A}, -then it requires -not only that the body of @code{B} be elaborated before @code{A}, -but also the -body of @code{C}, because @code{B} @code{with}'s @code{C}. -@end table +unit doing the @emph{with}, but also the bodies of all units that the +named unit uses, following @emph{with} links transitively. For example, +if we put a pragma @cite{Elaborate_All (B)} in unit @cite{A}, +then it requires not only that the body of @cite{B} be elaborated before @cite{A}, +but also the body of @cite{C}, because @cite{B} @emph{with}s @cite{C}. +@end itemize -@noindent We are now in a position to give a usage rule in Ada for avoiding elaboration problems, at least if dynamic dispatching and access to subprogram values are not used. We will handle these cases separately later. -The rule is simple. If a unit has elaboration code that can directly or -indirectly make a call to a subprogram in a @code{with}'ed unit, or instantiate -a generic package in a @code{with}'ed unit, -then if the @code{with}'ed unit does not have -pragma @code{Pure} or @code{Preelaborate}, then the client should have -a pragma @code{Elaborate_All} -for the @code{with}'ed unit. By following this rule a client is +The rule is simple: + +@emph{If a unit has elaboration code that can directly or +indirectly make a call to a subprogram in a |withed| unit, or instantiate +a generic package in a |withed| unit, +then if the |withed| unit does not have +pragma `Pure` or `Preelaborate`, then the client should have +a pragma `Elaborate_All`for the |withed| unit.*} + +By following this rule a client is assured that calls can be made without risk of an exception. For generic subprogram instantiations, the rule can be relaxed to -require only a pragma @code{Elaborate} since elaborating the body +require only a pragma @cite{Elaborate} since elaborating the body of a subprogram cannot cause any transitive elaboration (we are not calling the subprogram in this case, just elaborating its declaration). @@ -23544,21 +33301,29 @@ declaration). If this rule is not followed, then a program may be in one of four states: -@table @asis -@item No order exists + +@itemize * + +@item +@emph{No order exists} + No order of elaboration exists which follows the rules, taking into -account any @code{Elaborate}, @code{Elaborate_All}, -or @code{Elaborate_Body} pragmas. In +account any @cite{Elaborate}, @cite{Elaborate_All}, +or @cite{Elaborate_Body} pragmas. In this case, an Ada compiler must diagnose the situation at bind time, and refuse to build an executable program. -@item One or more orders exist, all incorrect +@item +@emph{One or more orders exist, all incorrect} + One or more acceptable elaboration orders exist, and all of them generate an elaboration order problem. In this case, the binder -can build an executable program, but @code{Program_Error} will be raised +can build an executable program, but @cite{Program_Error} will be raised when the program is run. -@item Several orders exist, some right, some incorrect +@item +@emph{Several orders exist, some right, some incorrect} + One or more acceptable elaboration orders exists, and some of them work, and some do not. The programmer has not controlled the order of elaboration, so the binder may or may not pick one of @@ -23567,16 +33332,17 @@ exception when it is run. This is the worst case, because it means that the program may fail when moved to another compiler, or even another version of the same compiler. -@item One or more orders exists, all correct +@item +@emph{One or more orders exists, all correct} + One ore more acceptable elaboration orders exist, and all of them work. In this case the program runs successfully. This state of affairs can be guaranteed by following the rule we gave above, but may be true even if the rule is not followed. -@end table +@end itemize -@noindent Note that one additional advantage of following our rules on the use -of @code{Elaborate} and @code{Elaborate_All} +of @cite{Elaborate} and @cite{Elaborate_All} is that the program continues to stay in the ideal (all orders OK) state even if maintenance changes some bodies of some units. Conversely, if a program that does @@ -23584,43 +33350,37 @@ not follow this rule happens to be safe at some point, this state of affairs may deteriorate silently as a result of maintenance changes. You may have noticed that the above discussion did not mention -the use of @code{Elaborate_Body}. This was a deliberate omission. If you -@code{with} an @code{Elaborate_Body} unit, it still may be the case that +the use of @cite{Elaborate_Body}. This was a deliberate omission. If you +@emph{with} an @cite{Elaborate_Body} unit, it still may be the case that code in the body makes calls to some other unit, so it is still necessary -to use @code{Elaborate_All} on such units. +to use @cite{Elaborate_All} on such units. -@node Controlling Elaboration in GNAT - Internal Calls +@node Controlling Elaboration in GNAT - Internal Calls,Controlling Elaboration in GNAT - External Calls,Controlling the Elaboration Order,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id5}@anchor{2b6}@anchor{gnat_ugn/elaboration_order_handling_in_gnat controlling-elaboration-in-gnat-internal-calls}@anchor{2b7} @section Controlling Elaboration in GNAT - Internal Calls -@noindent + In the case of internal calls, i.e., calls within a single package, the programmer has full control over the order of elaboration, and it is up to the programmer to elaborate declarations in an appropriate order. For example writing: -@smallexample @c ada -@group -@cartouche -@b{function} One @b{return} Float; +@example +function One return Float; Q : Float := One; -@b{function} One @b{return} Float @b{is} -@b{begin} - @b{return} 1.0; -@b{end} One; -@end cartouche -@end group -@end smallexample +function One return Float is +begin + return 1.0; +end One; +@end example -@noindent -will obviously raise @code{Program_Error} at run time, because function +will obviously raise @cite{Program_Error} at run time, because function One will be called before its body is elaborated. In this case GNAT will -generate a warning that the call will raise @code{Program_Error}: +generate a warning that the call will raise @cite{Program_Error}: -@smallexample -@group -@cartouche +@example 1. procedure y is 2. function One return Float; 3. @@ -23638,77 +33398,62 @@ generate a warning that the call will raise @code{Program_Error}: 11. begin 12. null; 13. end; -@end cartouche -@end group -@end smallexample +@end example -@noindent Note that in this particular case, it is likely that the call is safe, because -the function @code{One} does not access any global variables. +the function @cite{One} does not access any global variables. Nevertheless in Ada, we do not want the validity of the check to depend on the contents of the body (think about the separate compilation case), so this is still wrong, as we discussed in the previous sections. The error is easily corrected by rearranging the declarations so that the -body of @code{One} appears before the declaration containing the call -(note that in Ada 95 and Ada 2005, +body of @cite{One} appears before the declaration containing the call +(note that in Ada 95 as well as later versions of the Ada standard, declarations can appear in any order, so there is no restriction that would prevent this reordering, and if we write: -@smallexample @c ada -@group -@cartouche -@b{function} One @b{return} Float; +@example +function One return Float; -@b{function} One @b{return} Float @b{is} -@b{begin} - @b{return} 1.0; -@b{end} One; +function One return Float is +begin + return 1.0; +end One; Q : Float := One; -@end cartouche -@end group -@end smallexample +@end example -@noindent then all is well, no warning is generated, and no -@code{Program_Error} exception +@cite{Program_Error} exception will be raised. Things are more complicated when a chain of subprograms is executed: -@smallexample @c ada -@group -@cartouche -@b{function} A @b{return} Integer; -@b{function} B @b{return} Integer; -@b{function} C @b{return} Integer; +@example +function A return Integer; +function B return Integer; +function C return Integer; -@b{function} B @b{return} Integer @b{is} @b{begin} @b{return} A; @b{end}; -@b{function} C @b{return} Integer @b{is} @b{begin} @b{return} B; @b{end}; +function B return Integer is begin return A; end; +function C return Integer is begin return B; end; X : Integer := C; -@b{function} A @b{return} Integer @b{is} @b{begin} @b{return} 1; @b{end}; -@end cartouche -@end group -@end smallexample - -@noindent -Now the call to @code{C} -at elaboration time in the declaration of @code{X} is correct, because -the body of @code{C} is already elaborated, -and the call to @code{B} within the body of -@code{C} is correct, but the call -to @code{A} within the body of @code{B} is incorrect, because the body -of @code{A} has not been elaborated, so @code{Program_Error} -will be raised on the call to @code{A}. +function A return Integer is begin return 1; end; +@end example + +Now the call to @cite{C} +at elaboration time in the declaration of @cite{X} is correct, because +the body of @cite{C} is already elaborated, +and the call to @cite{B} within the body of +@cite{C} is correct, but the call +to @cite{A} within the body of @cite{B} is incorrect, because the body +of @cite{A} has not been elaborated, so @cite{Program_Error} +will be raised on the call to @cite{A}. In this case GNAT will generate a -warning that @code{Program_Error} may be +warning that @cite{Program_Error} may be raised at the point of the call. Let's look at the warning: -@smallexample -@group -@cartouche +@example 1. procedure x is 2. function A return Integer; 3. function B return Integer; @@ -23730,38 +33475,30 @@ raised at the point of the call. Let's look at the warning: 13. begin 14. null; 15. end; -@end cartouche -@end group -@end smallexample +@end example -@noindent -Note that the message here says ``may raise'', instead of the direct case, -where the message says ``will be raised''. That's because whether -@code{A} is +Note that the message here says 'may raise', instead of the direct case, +where the message says 'will be raised'. That's because whether +@cite{A} is actually called depends in general on run-time flow of control. -For example, if the body of @code{B} said +For example, if the body of @cite{B} said -@smallexample @c ada -@group -@cartouche -@b{function} B @b{return} Integer @b{is} -@b{begin} - @b{if} some-condition-depending-on-input-data @b{then} - @b{return} A; - @b{else} - @b{return} 1; - @b{end} @b{if}; -@b{end} B; -@end cartouche -@end group -@end smallexample +@example +function B return Integer is +begin + if some-condition-depending-on-input-data then + return A; + else + return 1; + end if; +end B; +@end example -@noindent then we could not know until run time whether the incorrect call to A would -actually occur, so @code{Program_Error} might +actually occur, so @cite{Program_Error} might or might not be raised. It is possible for a compiler to do a better job of analyzing bodies, to -determine whether or not @code{Program_Error} +determine whether or not @cite{Program_Error} might be raised, but it certainly couldn't do a perfect job (that would require solving the halting problem and is provably impossible), and because this is a warning anyway, it does @@ -23774,33 +33511,35 @@ real errors, and should be examined carefully and eliminated. In the rare case where a warning is bogus, it can be suppressed by any of the following methods: -@itemize @bullet -@item -Compile with the @option{-gnatws} switch set -@item -Suppress @code{Elaboration_Check} for the called subprogram +@itemize * -@item -Use pragma @code{Warnings_Off} to turn warnings off for the call +@item +Compile with the @emph{-gnatws} switch set + +@item +Suppress @cite{Elaboration_Check} for the called subprogram + +@item +Use pragma @cite{Warnings_Off} to turn warnings off for the call @end itemize -@noindent For the internal elaboration check case, GNAT by default generates the necessary run-time checks to ensure -that @code{Program_Error} is raised if any +that @cite{Program_Error} is raised if any call fails an elaboration check. Of course this can only happen if a warning has been issued as described above. The use of pragma -@code{Suppress (Elaboration_Check)} may (but is not guaranteed to) suppress +@cite{Suppress (Elaboration_Check)} may (but is not guaranteed to) suppress some of these checks, meaning that it may be possible (but is not guaranteed) for a program to be able to call a subprogram whose body -is not yet elaborated, without raising a @code{Program_Error} exception. +is not yet elaborated, without raising a @cite{Program_Error} exception. -@node Controlling Elaboration in GNAT - External Calls +@node Controlling Elaboration in GNAT - External Calls,Default Behavior in GNAT - Ensuring Safety,Controlling Elaboration in GNAT - Internal Calls,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id6}@anchor{2b8}@anchor{gnat_ugn/elaboration_order_handling_in_gnat controlling-elaboration-in-gnat-external-calls}@anchor{2b9} @section Controlling Elaboration in GNAT - External Calls -@noindent + The previous section discussed the case in which the execution of a particular thread of elaboration code occurred entirely within a single unit. This is the easy case to handle, because a programmer @@ -23810,188 +33549,161 @@ and which the compiler can easily detect. The situation is more complex when separate compilation is taken into account. Consider the following: -@smallexample @c ada -@cartouche -@group -@b{package} Math @b{is} - @b{function} Sqrt (Arg : Float) @b{return} Float; -@b{end} Math; - -@b{package} @b{body} Math @b{is} - @b{function} Sqrt (Arg : Float) @b{return} Float @b{is} - @b{begin} - @dots{} - @b{end} Sqrt; -@b{end} Math; -@end group -@group -@b{with} Math; -@b{package} Stuff @b{is} +@example +package Math is + function Sqrt (Arg : Float) return Float; +end Math; + +package body Math is + function Sqrt (Arg : Float) return Float is + begin + ... + end Sqrt; +end Math; + +with Math; +package Stuff is X : Float := Math.Sqrt (0.5); -@b{end} Stuff; - -@b{with} Stuff; -@b{procedure} Main @b{is} -@b{begin} - @dots{} -@b{end} Main; -@end group -@end cartouche -@end smallexample +end Stuff; + +with Stuff; +procedure Main is +begin + ... +end Main; +@end example -@noindent -where @code{Main} is the main program. When this program is executed, the +where @cite{Main} is the main program. When this program is executed, the elaboration code must first be executed, and one of the jobs of the binder is to determine the order in which the units of a program are to be elaborated. In this case we have four units: the spec and body -of @code{Math}, -the spec of @code{Stuff} and the body of @code{Main}). +of @cite{Math}, +the spec of @cite{Stuff} and the body of @cite{Main}). In what order should the four separate sections of elaboration code be executed? There are some restrictions in the order of elaboration that the binder -can choose. In particular, if unit U has a @code{with} -for a package @code{X}, then you -are assured that the spec of @code{X} +can choose. In particular, if unit U has a @emph{with} +for a package @cite{X}, then you +are assured that the spec of @cite{X} is elaborated before U , but you are -not assured that the body of @code{X} +not assured that the body of @cite{X} is elaborated before U. This means that in the above case, the binder is allowed to choose the order: -@smallexample +@example spec of Math spec of Stuff body of Math body of Main -@end smallexample +@end example -@noindent -but that's not good, because now the call to @code{Math.Sqrt} +but that's not good, because now the call to @cite{Math.Sqrt} that happens during -the elaboration of the @code{Stuff} -spec happens before the body of @code{Math.Sqrt} is -elaborated, and hence causes @code{Program_Error} exception to be raised. +the elaboration of the @cite{Stuff} +spec happens before the body of @cite{Math.Sqrt} is +elaborated, and hence causes @cite{Program_Error} exception to be raised. At first glance, one might say that the binder is misbehaving, because -obviously you want to elaborate the body of something you @code{with} -first, but +obviously you want to elaborate the body of something you @emph{with} first, but that is not a general rule that can be followed in all cases. Consider -@smallexample @c ada -@group -@cartouche -@b{package} X @b{is} @dots{} +@example +package X is ... -@b{package} Y @b{is} @dots{} +package Y is ... -@b{with} X; -@b{package} @b{body} Y @b{is} @dots{} +with X; +package body Y is ... -@b{with} Y; -@b{package} @b{body} X @b{is} @dots{} -@end cartouche -@end group -@end smallexample +with Y; +package body X is ... +@end example -@noindent This is a common arrangement, and, apart from the order of elaboration problems that might arise in connection with elaboration code, this works fine. A rule that says that you must first elaborate the body of anything you -@code{with} cannot work in this case: -the body of @code{X} @code{with}'s @code{Y}, +@emph{with} cannot work in this case: +the body of @cite{X} @emph{with}s @cite{Y}, which means you would have to -elaborate the body of @code{Y} first, but that @code{with}'s @code{X}, +elaborate the body of @cite{Y} first, but that @emph{with}s @cite{X}, which means -you have to elaborate the body of @code{X} first, but @dots{} and we have a +you have to elaborate the body of @cite{X} first, but ... and we have a loop that cannot be broken. It is true that the binder can in many cases guess an order of elaboration -that is unlikely to cause a @code{Program_Error} +that is unlikely to cause a @cite{Program_Error} exception to be raised, and it tries to do so (in the -above example of @code{Math/Stuff/Spec}, the GNAT binder will +above example of @cite{Math/Stuff/Spec}, the GNAT binder will by default -elaborate the body of @code{Math} right after its spec, so all will be well). +elaborate the body of @cite{Math} right after its spec, so all will be well). However, a program that blindly relies on the binder to be helpful can -get into trouble, as we discussed in the previous sections, so -GNAT +get into trouble, as we discussed in the previous sections, so GNAT provides a number of facilities for assisting the programmer in developing programs that are robust with respect to elaboration order. -@node Default Behavior in GNAT - Ensuring Safety +@node Default Behavior in GNAT - Ensuring Safety,Treatment of Pragma Elaborate,Controlling Elaboration in GNAT - External Calls,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id7}@anchor{2ba}@anchor{gnat_ugn/elaboration_order_handling_in_gnat default-behavior-in-gnat-ensuring-safety}@anchor{2bb} @section Default Behavior in GNAT - Ensuring Safety -@noindent + The default behavior in GNAT ensures elaboration safety. In its default mode GNAT implements the rule we previously described as the right approach. Let's restate it: -@itemize -@item @emph{If a unit has elaboration code that can directly or indirectly make a -call to a subprogram in a @code{with}'ed unit, or instantiate a generic -package in a @code{with}'ed unit, then if the @code{with}'ed unit -does not have pragma @code{Pure} or -@code{Preelaborate}, then the client should have an -@code{Elaborate_All} pragma for the @code{with}'ed unit.} +call to a subprogram in a |withed| unit, or instantiate a generic +package in a |withed| unit, then if the |withed| unit +does not have pragma `Pure` or `Preelaborate`, then the client should have an +`Elaborate_All` pragma for the |withed| unit.} @emph{In the case of instantiating a generic subprogram, it is always -sufficient to have only an @code{Elaborate} pragma for the -@code{with}'ed unit.} -@end itemize +sufficient to have only an `Elaborate` pragma for the +|withed| unit.} -@noindent By following this rule a client is assured that calls and instantiations can be made without risk of an exception. In this mode GNAT traces all calls that are potentially made from -elaboration code, and puts in any missing implicit @code{Elaborate} -and @code{Elaborate_All} pragmas. +elaboration code, and puts in any missing implicit @cite{Elaborate} +and @cite{Elaborate_All} pragmas. The advantage of this approach is that no elaboration problems are possible if the binder can find an elaboration order that is -consistent with these implicit @code{Elaborate} and -@code{Elaborate_All} pragmas. The +consistent with these implicit @cite{Elaborate} and +@cite{Elaborate_All} pragmas. The disadvantage of this approach is that no such order may exist. If the binder does not generate any diagnostics, then it means that it has found an elaboration order that is guaranteed to be safe. However, the binder -may still be relying on implicitly generated @code{Elaborate} and -@code{Elaborate_All} pragmas so portability to other compilers than GNAT is not +may still be relying on implicitly generated @cite{Elaborate} and +@cite{Elaborate_All} pragmas so portability to other compilers than GNAT is not guaranteed. If it is important to guarantee portability, then the compilations should -use the -@option{-gnatel} -(info messages for elaboration prag mas) switch. This will cause info messages -to be generated indicating the missing @code{Elaborate} and -@code{Elaborate_All} pragmas. +use the @emph{-gnatel} +(info messages for elaboration pragmas) switch. This will cause info messages +to be generated indicating the missing @cite{Elaborate} and +@cite{Elaborate_All} pragmas. Consider the following source program: -@smallexample @c ada -@group -@cartouche -@b{with} k; -@b{package} j @b{is} +@example +with k; +package j is m : integer := k.r; -@b{end}; -@end cartouche -@end group -@end smallexample +end; +@end example -@noindent where it is clear that there -should be a pragma @code{Elaborate_All} -for unit @code{k}. An implicit pragma will be generated, and it is +should be a pragma @cite{Elaborate_All} +for unit @cite{k}. An implicit pragma will be generated, and it is likely that the binder will be able to honor it. However, if you want to port this program to some other Ada compiler than GNAT. it is safer to include the pragma explicitly in the source. If this -unit is compiled with the -@option{-gnatel} +unit is compiled with the @emph{-gnatel} switch, then the compiler outputs an information message: -@smallexample -@group -@cartouche +@example 1. with k; 2. package j is 3. m : integer := k.r; @@ -24000,16 +33712,13 @@ switch, then the compiler outputs an information message: >>> info: missing pragma Elaborate_All for "k" 4. end; -@end cartouche -@end group -@end smallexample +@end example -@noindent and these messages can be used as a guide for supplying manually the missing pragmas. It is usually a bad idea to use this option during development. That's because it will tell you when you need to put in a pragma, but cannot tell you when it is time -to take it out. So the use of pragma @code{Elaborate_All} may lead to +to take it out. So the use of pragma @cite{Elaborate_All} may lead to unnecessary dependencies and even false circularities. This default mode is more restrictive than the Ada Reference @@ -24023,14 +33732,13 @@ and in particular must have the capability of implementing the standard dynamic model of elaboration with run-time checks. In GNAT, this standard mode can be achieved either by the use of -the @option{-gnatE} switch on the compiler (@command{gcc} or -@command{gnatmake}) command, or by the use of the configuration pragma: +the @emph{-gnatE} switch on the compiler (@emph{gcc} or +@emph{gnatmake}) command, or by the use of the configuration pragma: -@smallexample @c ada -@b{pragma} Elaboration_Checks (DYNAMIC); -@end smallexample +@example +pragma Elaboration_Checks (DYNAMIC); +@end example -@noindent Either approach will cause the unit affected to be compiled using the standard dynamic run-time elaboration checks described in the Ada Reference Manual. The static model is generally preferable, since it @@ -24038,7 +33746,7 @@ is clearly safer to rely on compile and link time checks rather than run-time checks. However, in the case of legacy code, it may be difficult to meet the requirements of the static model. This issue is further discussed in -@ref{What to Do If the Default Elaboration Behavior Fails}. +@ref{2bc,,What to Do If the Default Elaboration Behavior Fails}. Note that the static model provides a strict subset of the allowed behavior and programs of the Ada Reference Manual, so if you do @@ -24047,49 +33755,55 @@ then you are assured that your program will work using the dynamic model, providing that you remove any pragma Elaborate statements from the source. -@node Treatment of Pragma Elaborate +@node Treatment of Pragma Elaborate,Elaboration Issues for Library Tasks,Default Behavior in GNAT - Ensuring Safety,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat treatment-of-pragma-elaborate}@anchor{2bd}@anchor{gnat_ugn/elaboration_order_handling_in_gnat id8}@anchor{2be} @section Treatment of Pragma Elaborate -@cindex Pragma Elaborate -@noindent -The use of @code{pragma Elaborate} + +@geindex Pragma Elaborate + +The use of @cite{pragma Elaborate} should generally be avoided in Ada 95 and Ada 2005 programs, since there is no guarantee that transitive calls will be properly handled. Indeed at one point, this pragma was placed in Annex J (Obsolescent Features), on the grounds that it is never useful. Now that's a bit restrictive. In practice, the case in which -@code{pragma Elaborate} is useful is when the caller knows that there +@cite{pragma Elaborate} is useful is when the caller knows that there are no transitive calls, or that the called unit contains all necessary -transitive @code{pragma Elaborate} statements, and legacy code often +transitive @cite{pragma Elaborate} statements, and legacy code often contains such uses. Strictly speaking the static mode in GNAT should ignore such pragmas, since there is no assurance at compile time that the necessary safety conditions are met. In practice, this would cause GNAT to be incompatible with correctly written Ada 83 code that had all necessary -@code{pragma Elaborate} statements in place. Consequently, we made the +@cite{pragma Elaborate} statements in place. Consequently, we made the decision that GNAT in its default mode will believe that if it encounters -a @code{pragma Elaborate} then the programmer knows what they are doing, +a @cite{pragma Elaborate} then the programmer knows what they are doing, and it will trust that no elaboration errors can occur. The result of this decision is two-fold. First to be safe using the -static mode, you should remove all @code{pragma Elaborate} statements. +static mode, you should remove all @cite{pragma Elaborate} statements. Second, when fixing circularities in existing code, you can selectively -use @code{pragma Elaborate} statements to convince the static mode of -GNAT that it need not generate an implicit @code{pragma Elaborate_All} +use @cite{pragma Elaborate} statements to convince the static mode of +GNAT that it need not generate an implicit @cite{pragma Elaborate_All} statement. -When using the static mode with @option{-gnatwl}, any use of -@code{pragma Elaborate} will generate a warning about possible +When using the static mode with @emph{-gnatwl}, any use of +@cite{pragma Elaborate} will generate a warning about possible problems. -@node Elaboration Issues for Library Tasks +@node Elaboration Issues for Library Tasks,Mixing Elaboration Models,Treatment of Pragma Elaborate,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat elaboration-issues-for-library-tasks}@anchor{2bf}@anchor{gnat_ugn/elaboration_order_handling_in_gnat id9}@anchor{2c0} @section Elaboration Issues for Library Tasks -@cindex Library tasks, elaboration issues -@cindex Elaboration of library tasks -@noindent + +@geindex Library tasks +@geindex elaboration issues + +@geindex Elaboration of library tasks + In this section we examine special elaboration issues that arise for programs that declare library level tasks. @@ -24115,110 +33829,110 @@ a task is declared at the library level. This can definitely result in unexpected circularities. Consider the following example -@smallexample @c ada -@b{package} Decls @b{is} - @b{task} Lib_Task @b{is} - @b{entry} Start; - @b{end} Lib_Task; +@example +package Decls is + task Lib_Task is + entry Start; + end Lib_Task; - @b{type} My_Int @b{is} @b{new} Integer; + type My_Int is new Integer; - @b{function} Ident (M : My_Int) @b{return} My_Int; -@b{end} Decls; + function Ident (M : My_Int) return My_Int; +end Decls; -@b{with} Utils; -@b{package} @b{body} Decls @b{is} - @b{task} @b{body} Lib_Task @b{is} - @b{begin} - @b{accept} Start; +with Utils; +package body Decls is + task body Lib_Task is + begin + accept Start; Utils.Put_Val (2); - @b{end} Lib_Task; - - @b{function} Ident (M : My_Int) @b{return} My_Int @b{is} - @b{begin} - @b{return} M; - @b{end} Ident; -@b{end} Decls; - -@b{with} Decls; -@b{package} Utils @b{is} - @b{procedure} Put_Val (Arg : Decls.My_Int); -@b{end} Utils; - -@b{with} Text_IO; -@b{package} @b{body} Utils @b{is} - @b{procedure} Put_Val (Arg : Decls.My_Int) @b{is} - @b{begin} + end Lib_Task; + + function Ident (M : My_Int) return My_Int is + begin + return M; + end Ident; +end Decls; + +with Decls; +package Utils is + procedure Put_Val (Arg : Decls.My_Int); +end Utils; + +with Text_IO; +package body Utils is + procedure Put_Val (Arg : Decls.My_Int) is + begin Text_IO.Put_Line (Decls.My_Int'Image (Decls.Ident (Arg))); - @b{end} Put_Val; -@b{end} Utils; + end Put_Val; +end Utils; -@b{with} Decls; -@b{procedure} Main @b{is} -@b{begin} +with Decls; +procedure Main is +begin Decls.Lib_Task.Start; -@b{end}; -@end smallexample +end; +@end example -@noindent If the above example is compiled in the default static elaboration mode, then a circularity occurs. The circularity comes from the call -@code{Utils.Put_Val} in the task body of @code{Decls.Lib_Task}. Since +@cite{Utils.Put_Val} in the task body of @cite{Decls.Lib_Task}. Since this call occurs in elaboration code, we need an implicit pragma -@code{Elaborate_All} for @code{Utils}. This means that not only must -the spec and body of @code{Utils} be elaborated before the body -of @code{Decls}, but also the spec and body of any unit that is -@code{with'ed} by the body of @code{Utils} must also be elaborated before -the body of @code{Decls}. This is the transitive implication of -pragma @code{Elaborate_All} and it makes sense, because in general -the body of @code{Put_Val} might have a call to something in a -@code{with'ed} unit. - -In this case, the body of Utils (actually its spec) @code{with's} -@code{Decls}. Unfortunately this means that the body of @code{Decls} +@cite{Elaborate_All} for @cite{Utils}. This means that not only must +the spec and body of @cite{Utils} be elaborated before the body +of @cite{Decls}, but also the spec and body of any unit that is +@emph{with}ed by the body of @cite{Utils} must also be elaborated before +the body of @cite{Decls}. This is the transitive implication of +pragma @cite{Elaborate_All} and it makes sense, because in general +the body of @cite{Put_Val} might have a call to something in a +@emph{with}ed unit. + +In this case, the body of Utils (actually its spec) @emph{with}s +@cite{Decls}. Unfortunately this means that the body of @cite{Decls} must be elaborated before itself, in case there is a call from the -body of @code{Utils}. +body of @cite{Utils}. Here is the exact chain of events we are worrying about: -@enumerate -@item -In the body of @code{Decls} a call is made from within the body of a library -task to a subprogram in the package @code{Utils}. Since this call may + +@itemize * + +@item +In the body of @cite{Decls} a call is made from within the body of a library +task to a subprogram in the package @cite{Utils}. Since this call may occur at elaboration time (given that the task is activated at elaboration time), we have to assume the worst, i.e., that the call does happen at elaboration time. -@item -This means that the body and spec of @code{Util} must be elaborated before -the body of @code{Decls} so that this call does not cause an access before +@item +This means that the body and spec of @cite{Util} must be elaborated before +the body of @cite{Decls} so that this call does not cause an access before elaboration. -@item -Within the body of @code{Util}, specifically within the body of -@code{Util.Put_Val} there may be calls to any unit @code{with}'ed +@item +Within the body of @cite{Util}, specifically within the body of +@cite{Util.Put_Val} there may be calls to any unit @emph{with}ed by this package. -@item -One such @code{with}'ed package is package @code{Decls}, so there -might be a call to a subprogram in @code{Decls} in @code{Put_Val}. +@item +One such @emph{with}ed package is package @cite{Decls}, so there +might be a call to a subprogram in @cite{Decls} in @cite{Put_Val}. In fact there is such a call in this example, but we would have to assume that there was such a call even if it were not there, since -we are not supposed to write the body of @code{Decls} knowing what -is in the body of @code{Utils}; certainly in the case of the +we are not supposed to write the body of @cite{Decls} knowing what +is in the body of @cite{Utils}; certainly in the case of the static elaboration model, the compiler does not know what is in other bodies and must assume the worst. -@item -This means that the spec and body of @code{Decls} must also be +@item +This means that the spec and body of @cite{Decls} must also be elaborated before we elaborate the unit containing the call, but -that unit is @code{Decls}! This means that the body of @code{Decls} +that unit is @cite{Decls}! This means that the body of @cite{Decls} must be elaborated before itself, and that's a circularity. -@end enumerate +@end itemize -@noindent -Indeed, if you add an explicit pragma @code{Elaborate_All} for @code{Utils} in -the body of @code{Decls} you will get a true Ada Reference Manual +Indeed, if you add an explicit pragma @cite{Elaborate_All} for @cite{Utils} in +the body of @cite{Decls} you will get a true Ada Reference Manual circularity that makes the program illegal. In practice, we have found that problems with the static model of @@ -24226,7 +33940,7 @@ elaboration in existing code often arise from library tasks, so we must address this particular situation. Note that if we compile and run the program above, using the dynamic model of -elaboration (that is to say use the @option{-gnatE} switch), +elaboration (that is to say use the @emph{-gnatE} switch), then it compiles, binds, links, and runs, printing the expected result of 2. Therefore in some sense the circularity here is only apparent, and we need to capture @@ -24235,15 +33949,16 @@ tasks that have real elaboration problems. We have four possible answers to this question: -@itemize @bullet -@item +@itemize * + +@item Use the dynamic model of elaboration. -If we use the @option{-gnatE} switch, then as noted above, the program works. +If we use the @emph{-gnatE} switch, then as noted above, the program works. Why is this? If we examine the task body, it is apparent that the task cannot proceed past the -@code{accept} statement until after elaboration has been completed, because +@cite{accept} statement until after elaboration has been completed, because the corresponding entry call comes from the main program, not earlier. This is why the dynamic model works here. But that's really giving up on a precise analysis, and we prefer to take this approach only if we cannot @@ -24251,147 +33966,150 @@ solve the problem in any other manner. So let us examine two ways to reorganize the program to avoid the potential elaboration problem. -@item +@item Split library tasks into separate packages. Write separate packages, so that library tasks are isolated from other declarations as much as possible. Let us look at a variation on the above program. -@smallexample @c ada -@b{package} Decls1 @b{is} - @b{task} Lib_Task @b{is} - @b{entry} Start; - @b{end} Lib_Task; -@b{end} Decls1; - -@b{with} Utils; -@b{package} @b{body} Decls1 @b{is} - @b{task} @b{body} Lib_Task @b{is} - @b{begin} - @b{accept} Start; +@example +package Decls1 is + task Lib_Task is + entry Start; + end Lib_Task; +end Decls1; + +with Utils; +package body Decls1 is + task body Lib_Task is + begin + accept Start; Utils.Put_Val (2); - @b{end} Lib_Task; -@b{end} Decls1; - -@b{package} Decls2 @b{is} - @b{type} My_Int @b{is} @b{new} Integer; - @b{function} Ident (M : My_Int) @b{return} My_Int; -@b{end} Decls2; - -@b{with} Utils; -@b{package} @b{body} Decls2 @b{is} - @b{function} Ident (M : My_Int) @b{return} My_Int @b{is} - @b{begin} - @b{return} M; - @b{end} Ident; -@b{end} Decls2; - -@b{with} Decls2; -@b{package} Utils @b{is} - @b{procedure} Put_Val (Arg : Decls2.My_Int); -@b{end} Utils; - -@b{with} Text_IO; -@b{package} @b{body} Utils @b{is} - @b{procedure} Put_Val (Arg : Decls2.My_Int) @b{is} - @b{begin} + end Lib_Task; +end Decls1; + +package Decls2 is + type My_Int is new Integer; + function Ident (M : My_Int) return My_Int; +end Decls2; + +with Utils; +package body Decls2 is + function Ident (M : My_Int) return My_Int is + begin + return M; + end Ident; +end Decls2; + +with Decls2; +package Utils is + procedure Put_Val (Arg : Decls2.My_Int); +end Utils; + +with Text_IO; +package body Utils is + procedure Put_Val (Arg : Decls2.My_Int) is + begin Text_IO.Put_Line (Decls2.My_Int'Image (Decls2.Ident (Arg))); - @b{end} Put_Val; -@b{end} Utils; + end Put_Val; +end Utils; -@b{with} Decls1; -@b{procedure} Main @b{is} -@b{begin} +with Decls1; +procedure Main is +begin Decls1.Lib_Task.Start; -@b{end}; -@end smallexample +end; +@end example -@noindent -All we have done is to split @code{Decls} into two packages, one +All we have done is to split @cite{Decls} into two packages, one containing the library task, and one containing everything else. Now there is no cycle, and the program compiles, binds, links and executes using the default static model of elaboration. -@item +@item Declare separate task types. A significant part of the problem arises because of the use of the single task declaration form. This means that the elaboration of -the task type, and the elaboration of the task itself (i.e.@: the +the task type, and the elaboration of the task itself (i.e., the creation of the task) happen at the same time. A good rule of style in Ada is to always create explicit task types. By following the additional step of placing task objects in separate packages from the task type declaration, many elaboration problems are avoided. Here is another modified example of the example program: -@smallexample @c ada -@b{package} Decls @b{is} - @b{task} @b{type} Lib_Task_Type @b{is} - @b{entry} Start; - @b{end} Lib_Task_Type; +@example +package Decls is + task type Lib_Task_Type is + entry Start; + end Lib_Task_Type; - @b{type} My_Int @b{is} @b{new} Integer; + type My_Int is new Integer; - @b{function} Ident (M : My_Int) @b{return} My_Int; -@b{end} Decls; + function Ident (M : My_Int) return My_Int; +end Decls; -@b{with} Utils; -@b{package} @b{body} Decls @b{is} - @b{task} @b{body} Lib_Task_Type @b{is} - @b{begin} - @b{accept} Start; +with Utils; +package body Decls is + task body Lib_Task_Type is + begin + accept Start; Utils.Put_Val (2); - @b{end} Lib_Task_Type; - - @b{function} Ident (M : My_Int) @b{return} My_Int @b{is} - @b{begin} - @b{return} M; - @b{end} Ident; -@b{end} Decls; - -@b{with} Decls; -@b{package} Utils @b{is} - @b{procedure} Put_Val (Arg : Decls.My_Int); -@b{end} Utils; - -@b{with} Text_IO; -@b{package} @b{body} Utils @b{is} - @b{procedure} Put_Val (Arg : Decls.My_Int) @b{is} - @b{begin} + end Lib_Task_Type; + + function Ident (M : My_Int) return My_Int is + begin + return M; + end Ident; +end Decls; + +with Decls; +package Utils is + procedure Put_Val (Arg : Decls.My_Int); +end Utils; + +with Text_IO; +package body Utils is + procedure Put_Val (Arg : Decls.My_Int) is + begin Text_IO.Put_Line (Decls.My_Int'Image (Decls.Ident (Arg))); - @b{end} Put_Val; -@b{end} Utils; + end Put_Val; +end Utils; -@b{with} Decls; -@b{package} Declst @b{is} +with Decls; +package Declst is Lib_Task : Decls.Lib_Task_Type; -@b{end} Declst; +end Declst; -@b{with} Declst; -@b{procedure} Main @b{is} -@b{begin} +with Declst; +procedure Main is +begin Declst.Lib_Task.Start; -@b{end}; -@end smallexample +end; +@end example -@noindent -What we have done here is to replace the @code{task} declaration in -package @code{Decls} with a @code{task type} declaration. Then we -introduce a separate package @code{Declst} to contain the actual +What we have done here is to replace the @cite{task} declaration in +package @cite{Decls} with a @cite{task type} declaration. Then we +introduce a separate package @cite{Declst} to contain the actual task object. This separates the elaboration issues for -the @code{task type} +the @cite{task type} declaration, which causes no trouble, from the elaboration issues of the task object, which is also unproblematic, since it is now independent -of the elaboration of @code{Utils}. +of the elaboration of @cite{Utils}. This separation of concerns also corresponds to a generally sound engineering principle of separating declarations from instances. This version of the program also compiles, binds, links, and executes, generating the expected output. +@end itemize -@item +@geindex No_Entry_Calls_In_Elaboration_Code restriction + + +@itemize * + +@item Use No_Entry_Calls_In_Elaboration_Code restriction. -@cindex No_Entry_Calls_In_Elaboration_Code The previous two approaches described how a program can be restructured to avoid the special problems caused by library task bodies. in practice, @@ -24400,7 +34118,7 @@ so we must consider solutions that do not require massive rewriting. Let us consider more carefully why our original sample program works under the dynamic model of elaboration. The reason is that the code -in the task body blocks immediately on the @code{accept} +in the task body blocks immediately on the @cite{accept} statement. Now of course there is nothing to prohibit elaboration code from making entry calls (for example from another library level task), so we cannot tell in isolation that @@ -24408,8 +34126,8 @@ the task will not execute the accept statement during elaboration. However, in practice it is very unusual to see elaboration code make any entry calls, and the pattern of tasks starting -at elaboration time and then immediately blocking on @code{accept} or -@code{select} statements is very common. What this means is that +at elaboration time and then immediately blocking on @cite{accept} or +@cite{select} statements is very common. What this means is that the compiler is being too pessimistic when it analyzes the whole package body as though it might be executed at elaboration time. @@ -24419,18 +34137,17 @@ assumption most of the time, that could almost be made the default behavior), then we can compile all units of the program under control of the following configuration pragma: -@smallexample +@example pragma Restrictions (No_Entry_Calls_In_Elaboration_Code); -@end smallexample +@end example -@noindent -This pragma can be placed in the @file{gnat.adc} file in the usual +This pragma can be placed in the @code{gnat.adc} file in the usual manner. If we take our original unmodified program and compile it -in the presence of a @file{gnat.adc} containing the above pragma, +in the presence of a @code{gnat.adc} containing the above pragma, then once again, we can compile, bind, link, and execute, obtaining the expected result. In the presence of this pragma, the compiler does -not trace calls in a task body, that appear after the first @code{accept} -or @code{select} statement, and therefore does not report a potential +not trace calls in a task body, that appear after the first @cite{accept} +or @cite{select} statement, and therefore does not report a potential circularity in the original program. The compiler will check to the extent it can that the above @@ -24438,84 +34155,82 @@ restriction is not violated, but it is not always possible to do a complete check at compile time, so it is important to use this pragma only if the stated restriction is in fact met, that is to say no task receives an entry call before elaboration of all units is completed. - @end itemize -@node Mixing Elaboration Models +@node Mixing Elaboration Models,What to Do If the Default Elaboration Behavior Fails,Elaboration Issues for Library Tasks,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id10}@anchor{2c1}@anchor{gnat_ugn/elaboration_order_handling_in_gnat mixing-elaboration-models}@anchor{2c2} @section Mixing Elaboration Models -@noindent + + So far, we have assumed that the entire program is either compiled using the dynamic model or static model, ensuring consistency. It is possible to mix the two models, but rules have to be followed if this mixing is done to ensure that elaboration checks are not omitted. -The basic rule is that @emph{a unit compiled with the static model cannot -be @code{with'ed} by a unit compiled with the dynamic model}. The -reason for this is that in the static model, a unit assumes that +The basic rule is that +@strong{a unit compiled with the static model cannot +be |withed| by a unit compiled with the dynamic model}. +The reason for this is that in the static model, a unit assumes that its clients guarantee to use (the equivalent of) pragma -@code{Elaborate_All} so that no elaboration checks are required +@cite{Elaborate_All} so that no elaboration checks are required in inner subprograms, and this assumption is violated if the client is compiled with dynamic checks. The precise rule is as follows. A unit that is compiled with dynamic -checks can only @code{with} a unit that meets at least one of the +checks can only @emph{with} a unit that meets at least one of the following criteria: -@itemize @bullet -@item -The @code{with'ed} unit is itself compiled with dynamic elaboration -checks (that is with the @option{-gnatE} switch. +@itemize * -@item -The @code{with'ed} unit is an internal GNAT implementation unit from +@item +The @emph{with}ed unit is itself compiled with dynamic elaboration +checks (that is with the @emph{-gnatE} switch. + +@item +The @emph{with}ed unit is an internal GNAT implementation unit from the System, Interfaces, Ada, or GNAT hierarchies. -@item -The @code{with'ed} unit has pragma Preelaborate or pragma Pure. - -@item -The @code{with'ing} unit (that is the client) has an explicit pragma -@code{Elaborate_All} for the @code{with'ed} unit. +@item +The @emph{with}ed unit has pragma Preelaborate or pragma Pure. +@item +The @emph{with}ing unit (that is the client) has an explicit pragma +@cite{Elaborate_All} for the @emph{with}ed unit. @end itemize -@noindent If this rule is violated, that is if a unit with dynamic elaboration -checks @code{with's} a unit that does not meet one of the above four -criteria, then the binder (@code{gnatbind}) will issue a warning +checks @emph{with}s a unit that does not meet one of the above four +criteria, then the binder (@cite{gnatbind}) will issue a warning similar to that in the following example: -@smallexample +@example warning: "x.ads" has dynamic elaboration checks and with's warning: "y.ads" which has static elaboration checks -@end smallexample +@end example -@noindent These warnings indicate that the rule has been violated, and that as a result elaboration checks may be missed in the resulting executable file. -This warning may be suppressed using the @option{-ws} binder switch +This warning may be suppressed using the @emph{-ws} binder switch in the usual manner. One useful application of this mixing rule is in the case of a subsystem -which does not itself @code{with} units from the remainder of the +which does not itself @emph{with} units from the remainder of the application. In this case, the entire subsystem can be compiled with dynamic checks to resolve a circularity in the subsystem, while allowing the main application that uses this subsystem to be compiled using the more reliable default static model. -@node What to Do If the Default Elaboration Behavior Fails +@node What to Do If the Default Elaboration Behavior Fails,Elaboration for Indirect Calls,Mixing Elaboration Models,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id11}@anchor{2c3}@anchor{gnat_ugn/elaboration_order_handling_in_gnat what-to-do-if-the-default-elaboration-behavior-fails}@anchor{2bc} @section What to Do If the Default Elaboration Behavior Fails -@noindent + If the binder cannot find an acceptable order, it outputs detailed diagnostics. For example: -@smallexample -@group -@iftex -@leftskip=0cm -@end iftex + +@example error: elaboration circularity detected info: "proc (body)" must be elaborated before "pack (body)" info: reason: Elaborate_All probably needed in unit "pack (body)" @@ -24528,24 +34243,25 @@ info: which is withed by: info: "pack (body)" info: "pack (body)" must be elaborated before "proc (body)" info: reason: pragma Elaborate in unit "proc (body)" -@end group - -@end smallexample +@end example -@noindent In this case we have a cycle that the binder cannot break. On the one -hand, there is an explicit pragma Elaborate in @code{proc} for -@code{pack}. This means that the body of @code{pack} must be elaborated -before the body of @code{proc}. On the other hand, there is elaboration -code in @code{pack} that calls a subprogram in @code{proc}. This means +hand, there is an explicit pragma Elaborate in @cite{proc} for +@cite{pack}. This means that the body of @cite{pack} must be elaborated +before the body of @cite{proc}. On the other hand, there is elaboration +code in @cite{pack} that calls a subprogram in @cite{proc}. This means that for maximum safety, there should really be a pragma -Elaborate_All in @code{pack} for @code{proc} which would require that -the body of @code{proc} be elaborated before the body of -@code{pack}. Clearly both requirements cannot be satisfied. +Elaborate_All in @cite{pack} for @cite{proc} which would require that +the body of @cite{proc} be elaborated before the body of +@cite{pack}. Clearly both requirements cannot be satisfied. Faced with a circularity of this kind, you have three different options. -@table @asis -@item Fix the program + +@itemize * + +@item +@emph{Fix the program} + The most desirable option from the point of view of long-term maintenance is to rearrange the program so that the elaboration problems are avoided. One useful technique is to place the elaboration code into separate @@ -24555,127 +34271,133 @@ of initialization explicitly. Although this is the most desirable option, it may be impractical and involve too much modification, especially in the case of complex legacy code. -@item Perform dynamic checks -If the compilations are done using the -@option{-gnatE} +@item +@emph{Perform dynamic checks} + +If the compilations are done using the @emph{-gnatE} (dynamic elaboration check) switch, then GNAT behaves in a quite different manner. Dynamic checks are generated for all calls that could possibly result in raising an exception. With this switch, the compiler does not generate -implicit @code{Elaborate} or @code{Elaborate_All} pragmas. The behavior then is +implicit @cite{Elaborate} or @cite{Elaborate_All} pragmas. The behavior then is exactly as specified in the @cite{Ada Reference Manual}. The binder will generate -an executable program that may or may not raise @code{Program_Error}, and then +an executable program that may or may not raise @cite{Program_Error}, and then it is the programmer's job to ensure that it does not raise an exception. Note that it is important to compile all units with the switch, it cannot be used selectively. -@item Suppress checks +@item +@emph{Suppress checks} + The drawback of dynamic checks is that they generate a significant overhead at run time, both in space and time. If you are absolutely sure that your program cannot raise any elaboration exceptions, and you still want to use the dynamic elaboration model, then you can use the configuration pragma -@code{Suppress (Elaboration_Check)} to suppress all such checks. For -example this pragma could be placed in the @file{gnat.adc} file. +@cite{Suppress (Elaboration_Check)} to suppress all such checks. For +example this pragma could be placed in the @code{gnat.adc} file. + +@item +@emph{Suppress checks selectively} -@item Suppress checks selectively When you know that certain calls or instantiations in elaboration code cannot possibly lead to an elaboration error, and the binder nevertheless complains -about implicit @code{Elaborate} and @code{Elaborate_All} pragmas that lead to +about implicit @cite{Elaborate} and @cite{Elaborate_All} pragmas that lead to elaboration circularities, it is possible to remove those warnings locally and obtain a program that will bind. Clearly this can be unsafe, and it is the responsibility of the programmer to make sure that the resulting program has no -elaboration anomalies. The pragma @code{Suppress (Elaboration_Check)} can be +elaboration anomalies. The pragma @cite{Suppress (Elaboration_Check)} can be used with different granularity to suppress warnings and break elaboration circularities: -@itemize @bullet -@item + +@itemize * + +@item Place the pragma that names the called subprogram in the declarative part that contains the call. -@item +@item Place the pragma in the declarative part, without naming an entity. This disables warnings on all calls in the corresponding declarative region. -@item +@item Place the pragma in the package spec that declares the called subprogram, and name the subprogram. This disables warnings on all elaboration calls to that subprogram. -@item +@item Place the pragma in the package spec that declares the called subprogram, without naming any entity. This disables warnings on all elaboration calls to all subprograms declared in this spec. -@item Use Pragma Elaborate -As previously described in section @xref{Treatment of Pragma Elaborate}, -GNAT in static mode assumes that a @code{pragma} Elaborate indicates correctly +@item +Use Pragma Elaborate. + +As previously described in section @ref{2bd,,Treatment of Pragma Elaborate}, +GNAT in static mode assumes that a @cite{pragma} Elaborate indicates correctly that no elaboration checks are required on calls to the designated unit. There may be cases in which the caller knows that no transitive calls -can occur, so that a @code{pragma Elaborate} will be sufficient in a -case where @code{pragma Elaborate_All} would cause a circularity. +can occur, so that a @cite{pragma Elaborate} will be sufficient in a +case where @cite{pragma Elaborate_All} would cause a circularity. @end itemize -@noindent These five cases are listed in order of decreasing safety, and therefore require increasing programmer care in their application. Consider the following program: -@smallexample @c adanocomment -@b{package} Pack1 @b{is} - @b{function} F1 @b{return} Integer; +@example +package Pack1 is + function F1 return Integer; X1 : Integer; -@b{end} Pack1; +end Pack1; -@b{package} Pack2 @b{is} - @b{function} F2 @b{return} Integer; - @b{function} Pure (x : integer) @b{return} integer; +package Pack2 is + function F2 return Integer; + function Pure (x : integer) return integer; -- pragma Suppress (Elaboration_Check, On => Pure); -- (3) -- pragma Suppress (Elaboration_Check); -- (4) -@b{end} Pack2; - -@b{with} Pack2; -@b{package} @b{body} Pack1 @b{is} - @b{function} F1 @b{return} Integer @b{is} - @b{begin} - @b{return} 100; - @b{end} F1; +end Pack2; + +with Pack2; +package body Pack1 is + function F1 return Integer is + begin + return 100; + end F1; Val : integer := Pack2.Pure (11); -- Elab. call (1) -@b{begin} - @b{declare} +begin + declare -- pragma Suppress(Elaboration_Check, Pack2.F2); -- (1) -- pragma Suppress(Elaboration_Check); -- (2) - @b{begin} + begin X1 := Pack2.F2 + 1; -- Elab. call (2) - @b{end}; -@b{end} Pack1; - -@b{with} Pack1; -@b{package} @b{body} Pack2 @b{is} - @b{function} F2 @b{return} Integer @b{is} - @b{begin} - @b{return} Pack1.F1; - @b{end} F2; - @b{function} Pure (x : integer) @b{return} integer @b{is} - @b{begin} - @b{return} x ** 3 - 3 * x; - @b{end}; -@b{end} Pack2; - -@b{with} Pack1, Ada.Text_IO; -@b{procedure} Proc3 @b{is} -@b{begin} + end; +end Pack1; + +with Pack1; +package body Pack2 is + function F2 return Integer is + begin + return Pack1.F1; + end F2; + function Pure (x : integer) return integer is + begin + return x ** 3 - 3 * x; + end; +end Pack2; + +with Pack1, Ada.Text_IO; +procedure Proc3 is +begin Ada.Text_IO.Put_Line(Pack1.X1'Img); -- 101 -@b{end} Proc3; -@end smallexample +end Proc3; +@end example + In the absence of any pragmas, an attempt to bind this program produces the following diagnostics: -@smallexample -@group -@iftex -@leftskip=.5cm -@end iftex + +@example error: elaboration circularity detected info: "pack1 (body)" must be elaborated before "pack1 (body)" info: reason: Elaborate_All probably needed in unit "pack1 (body)" @@ -24689,45 +34411,38 @@ info: which must be elaborated along with its spec: info: "pack2 (spec)" info: which is withed by: info: "pack1 (body)" -@end group -@end smallexample -The sources of the circularity are the two calls to @code{Pack2.Pure} and -@code{Pack2.F2} in the body of @code{Pack1}. We can see that the call to +@end example + +The sources of the circularity are the two calls to @cite{Pack2.Pure} and +@cite{Pack2.F2} in the body of @cite{Pack1}. We can see that the call to F2 is safe, even though F2 calls F1, because the call appears after the elaboration of the body of F1. Therefore the pragma (1) is safe, and will remove the warning on the call. It is also possible to use pragma (2) because there are no other potentially unsafe calls in the block. -@noindent -The call to @code{Pure} is safe because this function does not depend on the -state of @code{Pack2}. Therefore any call to this function is safe, and it +The call to @cite{Pure} is safe because this function does not depend on the +state of @cite{Pack2}. Therefore any call to this function is safe, and it is correct to place pragma (3) in the corresponding package spec. -@noindent -Finally, we could place pragma (4) in the spec of @code{Pack2} to disable +Finally, we could place pragma (4) in the spec of @cite{Pack2} to disable warnings on all calls to functions declared therein. Note that this is not necessarily safe, and requires more detailed examination of the subprogram -bodies involved. In particular, a call to @code{F2} requires that @code{F1} +bodies involved. In particular, a call to @cite{F2} requires that @cite{F1} be already elaborated. -@end table +@end itemize -@noindent It is hard to generalize on which of these four approaches should be taken. Obviously if it is possible to fix the program so that the default treatment works, this is preferable, but this may not always be practical. -It is certainly simple enough to use -@option{-gnatE} +It is certainly simple enough to use @emph{-gnatE} but the danger in this case is that, even if the GNAT binder finds a correct elaboration order, it may not always do so, and certainly a binder from another Ada compiler might not. A combination of testing and analysis (for which the -information messages generated with the -@option{-gnatel} +information messages generated with the @emph{-gnatel} switch can be useful) must be used to ensure that the program is free of errors. One switch that is useful in this testing is the -@option{-p (pessimistic elaboration order)} -switch for -@code{gnatbind}. +@emph{-p (pessimistic elaboration order)} switch for @cite{gnatbind}. Normally the binder tries to find an order that has the best chance of avoiding elaboration problems. However, if this switch is used, the binder plays a devil's advocate role, and tries to choose the order that @@ -24736,7 +34451,7 @@ switch, then it has a better chance of being error free, but this is still not a guarantee. For an example of this approach in action, consider the C-tests (executable -tests) from the ACVC suite. If these are compiled and run with the default +tests) from the ACATS suite. If these are compiled and run with the default treatment, then all but one of them succeed without generating any error diagnostics from the binder. However, there is one test that fails, and this is not surprising, because the whole point of this test is to ensure @@ -24744,65 +34459,71 @@ that the compiler can handle cases where it is impossible to determine a correct order statically, and it checks that an exception is indeed raised at run time. -This one test must be compiled and run using the -@option{-gnatE} +This one test must be compiled and run using the @emph{-gnatE} switch, and then it passes. Alternatively, the entire suite can be run using this switch. It is never wrong to run with the dynamic elaboration switch if your code is correct, and we assume that the C-tests are indeed correct (it is less efficient, but efficiency is -not a factor in running the ACVC tests.) +not a factor in running the ACATS tests.) -@node Elaboration for Indirect Calls +@node Elaboration for Indirect Calls,Summary of Procedures for Elaboration Control,What to Do If the Default Elaboration Behavior Fails,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id12}@anchor{2c4}@anchor{gnat_ugn/elaboration_order_handling_in_gnat elaboration-for-indirect-calls}@anchor{2c5} @section Elaboration for Indirect Calls -@cindex Dispatching calls -@cindex Indirect calls -@noindent + +@geindex Dispatching calls + +@geindex Indirect calls + In rare cases, the static elaboration model fails to prevent dispatching calls to not-yet-elaborated subprograms. In such cases, we fall back to run-time checks; premature calls to any primitive operation of a tagged type before the body of the operation has been -elaborated will raise @code{Program_Error}. +elaborated will raise @cite{Program_Error}. Access-to-subprogram types, however, are handled conservatively, and do not require run-time checks. This was not true in earlier versions -of the compiler; you can use the @option{-gnatd.U} debug switch to +of the compiler; you can use the @emph{-gnatd.U} debug switch to revert to the old behavior if the new conservative behavior causes -elaboration cycles. Here, ``conservative'' means that if you do -@code{P'Access} during elaboration, the compiler will assume that you -might call @code{P} indirectly during elaboration, so it adds an -implicit @code{pragma Elaborate_All} on the library unit containing -@code{P}. The @option{-gnatd.U} switch is safe if you know there are +elaboration cycles. Here, 'conservative' means that if you do +@cite{P'Access} during elaboration, the compiler will assume that you +might call @cite{P} indirectly during elaboration, so it adds an +implicit @cite{pragma Elaborate_All} on the library unit containing +@cite{P}. The @emph{-gnatd.U} switch is safe if you know there are no such calls. If the program worked before, it will continue to work -with @option{-gnatd.U}. But beware that code modifications such as +with @emph{-gnatd.U}. But beware that code modifications such as adding an indirect call can cause erroneous behavior in the presence -of @option{-gnatd.U}. +of @emph{-gnatd.U}. -@node Summary of Procedures for Elaboration Control +@node Summary of Procedures for Elaboration Control,Other Elaboration Order Considerations,Elaboration for Indirect Calls,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id13}@anchor{2c6}@anchor{gnat_ugn/elaboration_order_handling_in_gnat summary-of-procedures-for-elaboration-control}@anchor{2c7} @section Summary of Procedures for Elaboration Control -@cindex Elaboration control -@noindent + +@geindex Elaboration control + First, compile your program with the default options, using none of the special elaboration control switches. If the binder successfully binds your program, then you can be confident that, apart from issues raised by the use of access-to-subprogram types and dynamic dispatching, the program is free of elaboration errors. If it is important that the program be portable to other compilers than GNAT, then use the -@option{-gnatel} -switch to generate messages about missing @code{Elaborate} or -@code{Elaborate_All} pragmas, and supply the missing pragmas. +@emph{-gnatel} +switch to generate messages about missing @cite{Elaborate} or +@cite{Elaborate_All} pragmas, and supply the missing pragmas. If the program fails to bind using the default static elaboration handling, then you can fix the program to eliminate the binder message, or recompile the entire program with the -@option{-gnatE} switch to generate dynamic elaboration checks, +@emph{-gnatE} switch to generate dynamic elaboration checks, and, if you are sure there really are no elaboration problems, -use a global pragma @code{Suppress (Elaboration_Check)}. +use a global pragma @cite{Suppress (Elaboration_Check)}. -@node Other Elaboration Order Considerations +@node Other Elaboration Order Considerations,Determining the Chosen Elaboration Order,Summary of Procedures for Elaboration Control,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat id14}@anchor{2c8}@anchor{gnat_ugn/elaboration_order_handling_in_gnat other-elaboration-order-considerations}@anchor{2c9} @section Other Elaboration Order Considerations -@noindent + + This section has been entirely concerned with the issue of finding a valid elaboration order, as defined by the Ada Reference Manual. In a case where several elaboration orders are valid, the task is to find one @@ -24819,7 +34540,7 @@ and this section has been all about avoiding such errors. In the case where more than one order of elaboration is possible, in the sense that access before elaboration errors are avoided, then any one of -the orders is ``correct'' in the sense that it meets the requirements of +the orders is 'correct' in the sense that it meets the requirements of the Ada Reference Manual, and no such error occurs. However, it may be the case for a given program, that there are @@ -24827,67 +34548,66 @@ constraints on the order of elaboration that come not from consideration of avoiding elaboration errors, but rather from extra-lingual logic requirements. Consider this example: -@smallexample @c ada -@b{with} Init_Constants; -@b{package} Constants @b{is} +@example +with Init_Constants; +package Constants is X : Integer := 0; Y : Integer := 0; -@b{end} Constants; +end Constants; -@b{package} Init_Constants @b{is} - @b{procedure} P; --@i{ require a body} -@b{end} Init_Constants; +package Init_Constants is + procedure P; --* require a body* +end Init_Constants; -@b{with} Constants; -@b{package} @b{body} Init_Constants @b{is} - @b{procedure} P @b{is} @b{begin} @b{null}; @b{end}; -@b{begin} +with Constants; +package body Init_Constants is + procedure P is begin null; end; +begin Constants.X := 3; Constants.Y := 4; -@b{end} Init_Constants; +end Init_Constants; -@b{with} Constants; -@b{package} Calc @b{is} +with Constants; +package Calc is Z : Integer := Constants.X + Constants.Y; -@b{end} Calc; +end Calc; -@b{with} Calc; -@b{with} Text_IO; @b{use} Text_IO; -@b{procedure} Main @b{is} -@b{begin} +with Calc; +with Text_IO; use Text_IO; +procedure Main is +begin Put_Line (Calc.Z'Img); -@b{end} Main; -@end smallexample +end Main; +@end example -@noindent In this example, there is more than one valid order of elaboration. For example both the following are correct orders: -@smallexample +@example Init_Constants spec Constants spec Calc spec Init_Constants body Main body +@end example - and +and +@example Init_Constants spec Init_Constants body Constants spec Calc spec Main body -@end smallexample +@end example -@noindent There is no language rule to prefer one or the other, both are correct from an order of elaboration point of view. But the programmatic effects of the two orders are very different. In the first, the elaboration routine -of @code{Calc} initializes @code{Z} to zero, and then the main program +of @cite{Calc} initializes @cite{Z} to zero, and then the main program runs with this value of zero. But in the second order, the elaboration -routine of @code{Calc} runs after the body of Init_Constants has set -@code{X} and @code{Y} and thus @code{Z} is set to 7 before @code{Main} -runs. +routine of @cite{Calc} runs after the body of Init_Constants has set +@cite{X} and @cite{Y} and thus @cite{Z} is set to 7 before @cite{Main} runs. One could perhaps by applying pretty clever non-artificial intelligence to the situation guess that it is more likely that the second order of @@ -24901,19 +34621,18 @@ If the program cares about the order of elaboration routines in a case like this, it is important to specify the order required. In this particular case, that could have been achieved by adding to the spec of Calc: -@smallexample @c ada -@b{pragma} Elaborate_All (Constants); -@end smallexample +@example +pragma Elaborate_All (Constants); +@end example -@noindent -which requires that the body (if any) and spec of @code{Constants}, -as well as the body and spec of any unit @code{with}'ed by -@code{Constants} be elaborated before @code{Calc} is elaborated. +which requires that the body (if any) and spec of @cite{Constants}, +as well as the body and spec of any unit @emph{with}ed by +@cite{Constants} be elaborated before @cite{Calc} is elaborated. Clearly no automatic method can always guess which alternative you require, and if you are working with legacy code that had constraints of this kind -which were not properly specified by adding @code{Elaborate} or -@code{Elaborate_All} pragmas, then indeed it is possible that two different +which were not properly specified by adding @cite{Elaborate} or +@cite{Elaborate_All} pragmas, then indeed it is possible that two different compilers can choose different orders. However, GNAT does attempt to diagnose the common situation where there @@ -24923,40 +34642,39 @@ indirectly initialized one or more of these variables. This is the situation in which a pragma Elaborate_Body is usually desirable, and GNAT will generate a warning that suggests this addition if it detects this situation. -The @code{gnatbind} -@option{-p} switch may be useful in smoking +The @cite{gnatbind} @emph{-p} switch may be useful in smoking out problems. This switch causes bodies to be elaborated as late as possible instead of as early as possible. In the example above, it would have forced the choice of the first elaboration order. If you get different results when using this switch, and particularly if one set of results is right, and one is wrong as far as you are concerned, it shows that you have some -missing @code{Elaborate} pragmas. For the example above, we have the +missing @cite{Elaborate} pragmas. For the example above, we have the following output: -@smallexample -gnatmake -f -q main -main +@example +$ gnatmake -f -q main +$ main 7 -gnatmake -f -q main -bargs -p -main +$ gnatmake -f -q main -bargs -p +$ main 0 -@end smallexample +@end example -@noindent It is of course quite unlikely that both these results are correct, so it is up to you in a case like this to investigate the source of the difference, by looking at the two elaboration orders that are chosen, and figuring out which is correct, and then adding the necessary -@code{Elaborate} or @code{Elaborate_All} pragmas to ensure the desired order. +@cite{Elaborate} or @cite{Elaborate_All} pragmas to ensure the desired order. -@node Determining the Chosen Elaboration Order +@node Determining the Chosen Elaboration Order,,Other Elaboration Order Considerations,Elaboration Order Handling in GNAT +@anchor{gnat_ugn/elaboration_order_handling_in_gnat determining-the-chosen-elaboration-order}@anchor{2ca}@anchor{gnat_ugn/elaboration_order_handling_in_gnat id15}@anchor{2cb} @section Determining the Chosen Elaboration Order -@noindent + To see the elaboration order that the binder chooses, you can look at -the last part of the b~xxx.adb binder output file. Here is an example: +the last part of the file:@cite{b~xxx.adb} binder output file. Here is an example: -@smallexample @c ada +@example System.Soft_Links'Elab_Body; E14 := True; System.Secondary_Stack'Elab_Body; @@ -24990,19 +34708,18 @@ E45 := True; Ada.Text_Io'Elab_Spec; Ada.Text_Io'Elab_Body; E07 := True; -@end smallexample +@end example -@noindent Here Elab_Spec elaborates the spec -and Elab_Body elaborates the body. The assignments to the Exx flags +and Elab_Body elaborates the body. The assignments to the @code{E@emph{xx}} flags flag that the corresponding body is now elaborated. You can also ask the binder to generate a more readable list of the elaboration order using the -@code{-l} switch when invoking the binder. Here is +@cite{-l} switch when invoking the binder. Here is an example of the output generated by this switch: -@smallexample +@example ada (spec) interfaces (spec) system (spec) @@ -25087,1062 +34804,288 @@ ada.text_io (spec) ada.text_io (body) text_io (spec) gdbstr (body) -@end smallexample - -@c ********************************** -@node Overflow Check Handling in GNAT -@appendix Overflow Check Handling in GNAT -@cindex Overflow checks -@cindex Checks (overflow) -@c ********************************** - -@menu -* Background:: -* Overflow Checking Modes in GNAT:: -* Specifying the Desired Mode:: -* Default Settings:: -* Implementation Notes:: -@end menu - - -@node Background -@section Background - -@noindent -Overflow checks are checks that the compiler may make to ensure -that intermediate results are not out of range. For example: - -@smallexample @c ada - A : Integer; - ... - A := A + 1; -@end smallexample - -@noindent -if @code{A} has the value @code{Integer'Last}, then the addition may cause -overflow since the result is out of range of the type @code{Integer}. -In this case @code{Constraint_Error} will be raised if checks are -enabled. +@end example -A trickier situation arises in examples like the following: +@node Inline Assembler,GNU Free Documentation License,Elaboration Order Handling in GNAT,Top +@anchor{gnat_ugn/inline_assembler inline-assembler}@anchor{12}@anchor{gnat_ugn/inline_assembler doc}@anchor{2cc}@anchor{gnat_ugn/inline_assembler id1}@anchor{2cd} +@chapter Inline Assembler -@smallexample @c ada - A, C : Integer; - ... - A := (A + 1) + C; -@end smallexample -@noindent -where @code{A} is @code{Integer'Last} and @code{C} is @code{-1}. -Now the final result of the expression on the right hand side is -@code{Integer'Last} which is in range, but the question arises whether the -intermediate addition of @code{(A + 1)} raises an overflow error. +@geindex Inline Assembler -The (perhaps surprising) answer is that the Ada language -definition does not answer this question. Instead it leaves -it up to the implementation to do one of two things if overflow -checks are enabled. - -@itemize @bullet -@item -raise an exception (@code{Constraint_Error}), or - -@item -yield the correct mathematical result which is then used in -subsequent operations. -@end itemize - -@noindent -If the compiler chooses the first approach, then the assignment of this -example will indeed raise @code{Constraint_Error} if overflow checking is -enabled, or result in erroneous execution if overflow checks are suppressed. - -But if the compiler -chooses the second approach, then it can perform both additions yielding -the correct mathematical result, which is in range, so no exception -will be raised, and the right result is obtained, regardless of whether -overflow checks are suppressed. - -Note that in the first example an -exception will be raised in either case, since if the compiler -gives the correct mathematical result for the addition, it will -be out of range of the target type of the assignment, and thus -fails the range check. - -This lack of specified behavior in the handling of overflow for -intermediate results is a source of non-portability, and can thus -be problematic when programs are ported. Most typically this arises -in a situation where the original compiler did not raise an exception, -and then the application is moved to a compiler where the check is -performed on the intermediate result and an unexpected exception is -raised. - -Furthermore, when using Ada 2012's preconditions and other -assertion forms, another issue arises. Consider: - -@smallexample @c ada - @b{procedure} P (A, B : Integer) @b{with} - Pre => A + B <= Integer'Last; -@end smallexample - -@noindent -One often wants to regard arithmetic in a context like this from -a mathematical point of view. So for example, if the two actual parameters -for a call to @code{P} are both @code{Integer'Last}, then -the precondition should be regarded as False. If we are executing -in a mode with run-time checks enabled for preconditions, then we would -like this precondition to fail, rather than raising an exception -because of the intermediate overflow. - -However, the language definition leaves the specification of -whether the above condition fails (raising @code{Assert_Error}) or -causes an intermediate overflow (raising @code{Constraint_Error}) -up to the implementation. - -The situation is worse in a case such as the following: - -@smallexample @c ada - @b{procedure} Q (A, B, C : Integer) @b{with} - Pre => A + B + C <= Integer'Last; -@end smallexample - -@noindent -Consider the call - -@smallexample @c ada - Q (A => Integer'Last, B => 1, C => -1); -@end smallexample - -@noindent -From a mathematical point of view the precondition -is True, but at run time we may (but are not guaranteed to) get an -exception raised because of the intermediate overflow (and we really -would prefer this precondition to be considered True at run time). - -@node Overflow Checking Modes in GNAT -@section Overflow Checking Modes in GNAT - -@noindent -To deal with the portability issue, and with the problem of -mathematical versus run-time interpretation of the expressions in -assertions, GNAT provides comprehensive control over the handling -of intermediate overflow. GNAT can operate in three modes, and -furthemore, permits separate selection of operating modes for -the expressions within assertions (here the term ``assertions'' -is used in the technical sense, which includes preconditions and so forth) -and for expressions appearing outside assertions. - -The three modes are: - -@itemize @bullet -@item @i{Use base type for intermediate operations} (@code{STRICT}) - - In this mode, all intermediate results for predefined arithmetic - operators are computed using the base type, and the result must - be in range of the base type. If this is not the - case then either an exception is raised (if overflow checks are - enabled) or the execution is erroneous (if overflow checks are suppressed). - This is the normal default mode. - -@item @i{Most intermediate overflows avoided} (@code{MINIMIZED}) - - In this mode, the compiler attempts to avoid intermediate overflows by - using a larger integer type, typically @code{Long_Long_Integer}, - as the type in which arithmetic is - performed for predefined arithmetic operators. This may be slightly more - expensive at - run time (compared to suppressing intermediate overflow checks), though - the cost is negligible on modern 64-bit machines. For the examples given - earlier, no intermediate overflows would have resulted in exceptions, - since the intermediate results are all in the range of - @code{Long_Long_Integer} (typically 64-bits on nearly all implementations - of GNAT). In addition, if checks are enabled, this reduces the number of - checks that must be made, so this choice may actually result in an - improvement in space and time behavior. - - However, there are cases where @code{Long_Long_Integer} is not large - enough, consider the following example: - -@smallexample @c ada - @b{procedure} R (A, B, C, D : Integer) @b{with} - Pre => (A**2 * B**2) / (C**2 * D**2) <= 10; -@end smallexample - - where @code{A} = @code{B} = @code{C} = @code{D} = @code{Integer'Last}. - Now the intermediate results are - out of the range of @code{Long_Long_Integer} even though the final result - is in range and the precondition is True (from a mathematical point - of view). In such a case, operating in this mode, an overflow occurs - for the intermediate computation (which is why this mode - says @i{most} intermediate overflows are avoided). In this case, - an exception is raised if overflow checks are enabled, and the - execution is erroneous if overflow checks are suppressed. - -@item @i{All intermediate overflows avoided} (@code{ELIMINATED}) - - In this mode, the compiler avoids all intermediate overflows - by using arbitrary precision arithmetic as required. In this - mode, the above example with @code{A**2 * B**2} would - not cause intermediate overflow, because the intermediate result - would be evaluated using sufficient precision, and the result - of evaluating the precondition would be True. - - This mode has the advantage of avoiding any intermediate - overflows, but at the expense of significant run-time overhead, - including the use of a library (included automatically in this - mode) for multiple-precision arithmetic. - - This mode provides cleaner semantics for assertions, since now - the run-time behavior emulates true arithmetic behavior for the - predefined arithmetic operators, meaning that there is never a - conflict between the mathematical view of the assertion, and its - run-time behavior. - - Note that in this mode, the behavior is unaffected by whether or - not overflow checks are suppressed, since overflow does not occur. - It is possible for gigantic intermediate expressions to raise - @code{Storage_Error} as a result of attempting to compute the - results of such expressions (e.g. @code{Integer'Last ** Integer'Last}) - but overflow is impossible. - - -@end itemize - -@noindent - Note that these modes apply only to the evaluation of predefined - arithmetic, membership, and comparison operators for signed integer - aritmetic. - - For fixed-point arithmetic, checks can be suppressed. But if checks - are enabled - then fixed-point values are always checked for overflow against the - base type for intermediate expressions (that is such checks always - operate in the equivalent of @code{STRICT} mode). - - For floating-point, on nearly all architectures, @code{Machine_Overflows} - is False, and IEEE infinities are generated, so overflow exceptions - are never raised. If you want to avoid infinities, and check that - final results of expressions are in range, then you can declare a - constrained floating-point type, and range checks will be carried - out in the normal manner (with infinite values always failing all - range checks). - - -@c ------------------------- -@node Specifying the Desired Mode -@section Specifying the Desired Mode - -@noindent -The desired mode of for handling intermediate overflow can be specified using -either the @code{Overflow_Mode} pragma or an equivalent compiler switch. -The pragma has the form -@cindex pragma @code{Overflow_Mode} - -@smallexample @c ada - @b{pragma} Overflow_Mode ([General =>] MODE [, [Assertions =>] MODE]); -@end smallexample - -@noindent -where @code{MODE} is one of - -@itemize @bullet -@item @code{STRICT}: intermediate overflows checked (using base type) -@item @code{MINIMIZED}: minimize intermediate overflows -@item @code{ELIMINATED}: eliminate intermediate overflows -@end itemize - -@noindent -The case is ignored, so @code{MINIMIZED}, @code{Minimized} and -@code{minimized} all have the same effect. - -If only the @code{General} parameter is present, then the given @code{MODE} -applies -to expressions both within and outside assertions. If both arguments -are present, then @code{General} applies to expressions outside assertions, -and @code{Assertions} applies to expressions within assertions. For example: - -@smallexample @c ada - @b{pragma} Overflow_Mode - (General => Minimized, Assertions => Eliminated); -@end smallexample - -@noindent -specifies that general expressions outside assertions be evaluated -in ``minimize intermediate overflows'' mode, and expressions within -assertions be evaluated in ``eliminate intermediate overflows'' mode. -This is often a reasonable choice, avoiding excessive overhead -outside assertions, but assuring a high degree of portability -when importing code from another compiler, while incurring -the extra overhead for assertion expressions to ensure that -the behavior at run time matches the expected mathematical -behavior. - -The @code{Overflow_Mode} pragma has the same scoping and placement -rules as pragma @code{Suppress}, so it can occur either as a -configuration pragma, specifying a default for the whole -program, or in a declarative scope, where it applies to the -remaining declarations and statements in that scope. - -Note that pragma @code{Overflow_Mode} does not affect whether -overflow checks are enabled or suppressed. It only controls the -method used to compute intermediate values. To control whether -overflow checking is enabled or suppressed, use pragma @code{Suppress} -or @code{Unsuppress} in the usual manner - -Additionally, a compiler switch @option{-gnato?} or @option{-gnato??} -can be used to control the checking mode default (which can be subsequently -overridden using pragmas). -@cindex @option{-gnato?} (gcc) -@cindex @option{-gnato??} (gcc) - -Here `@code{?}' is one of the digits `@code{1}' through `@code{3}': - -@itemize @bullet -@item @code{1}: -use base type for intermediate operations (@code{STRICT}) -@item @code{2}: -minimize intermediate overflows (@code{MINIMIZED}) -@item @code{3}: -eliminate intermediate overflows (@code{ELIMINATED}) -@end itemize - -@noindent -As with the pragma, if only one digit appears then it applies to all -cases; if two digits are given, then the first applies outside -assertions, and the second within assertions. Thus the equivalent -of the example pragma above would be -@option{-gnato23}. - -If no digits follow the @option{-gnato}, then it is equivalent to -@option{-gnato11}, -causing all intermediate operations to be computed using the base -type (@code{STRICT} mode). - -In addition to setting the mode used for computation of intermediate -results, the @code{-gnato} switch also enables overflow checking (which -is suppressed by default). It thus combines the effect of using -a pragma @code{Overflow_Mode} and pragma @code{Unsuppress}. - - -@c ------------------------- -@node Default Settings -@section Default Settings - -The default mode for overflow checks is - -@smallexample - General => Strict -@end smallexample - -@noindent -which causes all computations both inside and outside assertions to use -the base type. In addition overflow checks are suppressed. - -This retains compatibility with previous versions of -GNAT which suppressed overflow checks by default and always -used the base type for computation of intermediate results. - -The switch @option{-gnato} (with no digits following) is equivalent to -@cindex @option{-gnato} (gcc) - -@smallexample - General => Strict -@end smallexample - -@noindent -which causes overflow checking of all intermediate overflows -both inside and outside assertions against the base type. -This provides compatibility -with this switch as implemented in previous versions of GNAT. - -The pragma @code{Suppress (Overflow_Check)} disables overflow -checking, but it has no effect on the method used for computing -intermediate results. - -The pragma @code{Unsuppress (Overflow_Check)} enables overflow -checking, but it has no effect on the method used for computing -intermediate results. - -@c ------------------------- -@node Implementation Notes -@section Implementation Notes - -In practice on typical 64-bit machines, the @code{MINIMIZED} mode is -reasonably efficient, and can be generally used. It also helps -to ensure compatibility with code imported from some other -compiler to GNAT. +If you need to write low-level software that interacts directly +with the hardware, Ada provides two ways to incorporate assembly +language code into your program. First, you can import and invoke +external routines written in assembly language, an Ada feature fully +supported by GNAT. However, for small sections of code it may be simpler +or more efficient to include assembly language statements directly +in your Ada source program, using the facilities of the implementation-defined +package @cite{System.Machine_Code}, which incorporates the gcc +Inline Assembler. The Inline Assembler approach offers a number of advantages, +including the following: -Setting all intermediate overflows checking (@code{CHECKED} mode) -makes sense if you want to -make sure that your code is compatible with any other possible -Ada implementation. This may be useful in ensuring portability -for code that is to be exported to some other compiler than GNAT. +@itemize * -The Ada standard allows the reassociation of expressions at -the same precedence level if no parentheses are present. For -example, @w{@code{A+B+C}} parses as though it were @w{@code{(A+B)+C}}, but -the compiler can reintepret this as @w{@code{A+(B+C)}}, possibly -introducing or eliminating an overflow exception. The GNAT -compiler never takes advantage of this freedom, and the -expression @w{@code{A+B+C}} will be evaluated as @w{@code{(A+B)+C}}. -If you need the other order, you can write the parentheses -explicitly @w{@code{A+(B+C)}} and GNAT will respect this order. +@item +No need to use non-Ada tools -The use of @code{ELIMINATED} mode will cause the compiler to -automatically include an appropriate arbitrary precision -integer arithmetic package. The compiler will make calls -to this package, though only in cases where it cannot be -sure that @code{Long_Long_Integer} is sufficient to guard against -intermediate overflows. This package does not use dynamic -alllocation, but it does use the secondary stack, so an -appropriate secondary stack package must be present (this -is always true for standard full Ada, but may require -specific steps for restricted run times such as ZFP). +@item +Consistent interface over different targets -Although @code{ELIMINATED} mode causes expressions to use arbitrary -precision arithmetic, avoiding overflow, the final result -must be in an appropriate range. This is true even if the -final result is of type @code{[Long_[Long_]]Integer'Base}, which -still has the same bounds as its associated constrained -type at run-time. +@item +Automatic usage of the proper calling conventions -Currently, the @code{ELIMINATED} mode is only available on target -platforms for which @code{Long_Long_Integer} is 64-bits (nearly all GNAT -platforms). +@item +Access to Ada constants and variables -@c ******************************* -@node Conditional Compilation -@appendix Conditional Compilation -@c ******************************* -@cindex Conditional compilation +@item +Definition of intrinsic routines -@noindent -It is often necessary to arrange for a single source program -to serve multiple purposes, where it is compiled in different -ways to achieve these different goals. Some examples of the -need for this feature are +@item +Possibility of inlining a subprogram comprising assembler code -@itemize @bullet -@item Adapting a program to a different hardware environment -@item Adapting a program to a different target architecture -@item Turning debugging features on and off -@item Arranging for a program to compile with different compilers +@item +Code optimizer can take Inline Assembler code into account @end itemize -@noindent -In C, or C++, the typical approach would be to use the preprocessor -that is defined as part of the language. The Ada language does not -contain such a feature. This is not an oversight, but rather a very -deliberate design decision, based on the experience that overuse of -the preprocessing features in C and C++ can result in programs that -are extremely difficult to maintain. For example, if we have ten -switches that can be on or off, this means that there are a thousand -separate programs, any one of which might not even be syntactically -correct, and even if syntactically correct, the resulting program -might not work correctly. Testing all combinations can quickly become -impossible. - -Nevertheless, the need to tailor programs certainly exists, and in -this Appendix we will discuss how this can -be achieved using Ada in general, and GNAT in particular. +This appendix presents a series of examples to show you how to use +the Inline Assembler. Although it focuses on the Intel x86, +the general approach applies also to other processors. +It is assumed that you are familiar with Ada +and with assembly language programming. @menu -* Use of Boolean Constants:: -* Debugging - A Special Case:: -* Conditionalizing Declarations:: -* Use of Alternative Implementations:: -* Preprocessing:: +* Basic Assembler Syntax:: +* A Simple Example of Inline Assembler:: +* Output Variables in Inline Assembler:: +* Input Variables in Inline Assembler:: +* Inlining Inline Assembler Code:: +* Other Asm Functionality:: + @end menu -@node Use of Boolean Constants -@section Use of Boolean Constants +@node Basic Assembler Syntax,A Simple Example of Inline Assembler,,Inline Assembler +@anchor{gnat_ugn/inline_assembler id2}@anchor{2ce}@anchor{gnat_ugn/inline_assembler basic-assembler-syntax}@anchor{2cf} +@section Basic Assembler Syntax -@noindent -In the case where the difference is simply which code -sequence is executed, the cleanest solution is to use Boolean -constants to control which code is executed. -@smallexample @c ada -@group -FP_Initialize_Required : @b{constant} Boolean := True; -@dots{} -@b{if} FP_Initialize_Required @b{then} -@dots{} -@b{end} @b{if}; -@end group -@end smallexample - -@noindent -Not only will the code inside the @code{if} statement not be executed if -the constant Boolean is @code{False}, but it will also be completely -deleted from the program. -However, the code is only deleted after the @code{if} statement -has been checked for syntactic and semantic correctness. -(In contrast, with preprocessors the code is deleted before the -compiler ever gets to see it, so it is not checked until the switch -is turned on.) -@cindex Preprocessors (contrasted with conditional compilation) +The assembler used by GNAT and gcc is based not on the Intel assembly +language, but rather on a language that descends from the AT&T Unix +assembler @emph{as} (and which is often referred to as 'AT&T syntax'). +The following table summarizes the main features of @emph{as} syntax +and points out the differences from the Intel conventions. +See the gcc @emph{as} and @emph{gas} (an @emph{as} macro +pre-processor) documentation for further information. -Typically the Boolean constants will be in a separate package, -something like: -@smallexample @c ada -@group -@b{package} Config @b{is} - FP_Initialize_Required : @b{constant} Boolean := True; - Reset_Available : @b{constant} Boolean := False; - @dots{} -@b{end} Config; -@end group -@end smallexample +@display +@emph{Register names}@w{ } +@display +gcc / @emph{as}: Prefix with '%'; for example @cite{%eax}@w{ } +Intel: No extra punctuation; for example @cite{eax}@w{ } +@end display +@end display -@noindent -The @code{Config} package exists in multiple forms for the various targets, -with an appropriate script selecting the version of @code{Config} needed. -Then any other unit requiring conditional compilation can do a @code{with} -of @code{Config} to make the constants visible. -@node Debugging - A Special Case -@section Debugging - A Special Case -@noindent -A common use of conditional code is to execute statements (for example -dynamic checks, or output of intermediate results) under control of a -debug switch, so that the debugging behavior can be turned on and off. -This can be done using a Boolean constant to control whether the code -is active: +@display +@emph{Immediate operand}@w{ } +@display +gcc / @emph{as}: Prefix with '$'; for example @cite{$4}@w{ } +Intel: No extra punctuation; for example @cite{4}@w{ } +@end display +@end display -@smallexample @c ada -@group -@b{if} Debugging @b{then} - Put_Line ("got to the first stage!"); -@b{end} @b{if}; -@end group -@end smallexample -@noindent -or -@smallexample @c ada -@group -@b{if} Debugging @b{and} @b{then} Temperature > 999.0 @b{then} - @b{raise} Temperature_Crazy; -@b{end} @b{if}; -@end group -@end smallexample -@noindent -Since this is a common case, there are special features to deal with -this in a convenient manner. For the case of tests, Ada 2005 has added -a pragma @code{Assert} that can be used for such tests. This pragma is modeled -@cindex pragma @code{Assert} -on the @code{Assert} pragma that has always been available in GNAT, so this -feature may be used with GNAT even if you are not using Ada 2005 features. -The use of pragma @code{Assert} is described in -@ref{Pragma Assert,,, gnat_rm, GNAT Reference Manual}, but as an -example, the last test could be written: +@display +@emph{Address}@w{ } +@display +gcc / @emph{as}: Prefix with '$'; for example @cite{$loc}@w{ } +Intel: No extra punctuation; for example @cite{loc}@w{ } +@end display +@end display -@smallexample @c ada -@b{pragma} Assert (Temperature <= 999.0, "Temperature Crazy"); -@end smallexample -@noindent -or simply -@smallexample @c ada -@b{pragma} Assert (Temperature <= 999.0); -@end smallexample -@noindent -In both cases, if assertions are active and the temperature is excessive, -the exception @code{Assert_Failure} will be raised, with the given string in -the first case or a string indicating the location of the pragma in the second -case used as the exception message. +@display +@emph{Memory contents}@w{ } +@display +gcc / @emph{as}: No extra punctuation; for example @cite{loc}@w{ } +Intel: Square brackets; for example @cite{[loc]}@w{ } +@end display +@end display -You can turn assertions on and off by using the @code{Assertion_Policy} -pragma. -@cindex pragma @code{Assertion_Policy} -This is an Ada 2005 pragma which is implemented in all modes by -GNAT, but only in the latest versions of GNAT which include Ada 2005 -capability. Alternatively, you can use the @option{-gnata} switch -@cindex @option{-gnata} switch -to enable assertions from the command line (this is recognized by all versions -of GNAT). -For the example above with the @code{Put_Line}, the GNAT-specific pragma -@code{Debug} can be used: -@cindex pragma @code{Debug} -@smallexample @c ada -@b{pragma} Debug (Put_Line ("got to the first stage!")); -@end smallexample -@noindent -If debug pragmas are enabled, the argument, which must be of the form of -a procedure call, is executed (in this case, @code{Put_Line} will be called). -Only one call can be present, but of course a special debugging procedure -containing any code you like can be included in the program and then -called in a pragma @code{Debug} argument as needed. +@display +@emph{Register contents}@w{ } +@display +gcc / @emph{as}: Parentheses; for example @cite{(%eax)}@w{ } +Intel: Square brackets; for example @cite{[eax]}@w{ } +@end display +@end display -One advantage of pragma @code{Debug} over the @code{if Debugging then} -construct is that pragma @code{Debug} can appear in declarative contexts, -such as at the very beginning of a procedure, before local declarations have -been elaborated. -Debug pragmas are enabled using either the @option{-gnata} switch that also -controls assertions, or with a separate Debug_Policy pragma. -@cindex pragma @code{Debug_Policy} -The latter pragma is new in the Ada 2005 versions of GNAT (but it can be used -in Ada 95 and Ada 83 programs as well), and is analogous to -pragma @code{Assertion_Policy} to control assertions. -@code{Assertion_Policy} and @code{Debug_Policy} are configuration pragmas, -and thus they can appear in @file{gnat.adc} if you are not using a -project file, or in the file designated to contain configuration pragmas -in a project file. -They then apply to all subsequent compilations. In practice the use of -the @option{-gnata} switch is often the most convenient method of controlling -the status of these pragmas. -Note that a pragma is not a statement, so in contexts where a statement -sequence is required, you can't just write a pragma on its own. You have -to add a @code{null} statement. +@display +@emph{Hexadecimal numbers}@w{ } +@display +gcc / @emph{as}: Leading '0x' (C language syntax); for example @cite{0xA0}@w{ } +Intel: Trailing 'h'; for example @cite{A0h}@w{ } +@end display +@end display -@smallexample @c ada -@group -@b{if} @dots{} @b{then} - @dots{} -- some statements -@b{else} - @b{pragma} Assert (Num_Cases < 10); - @b{null}; -@b{end} @b{if}; -@end group -@end smallexample -@node Conditionalizing Declarations -@section Conditionalizing Declarations -@noindent -In some cases, it may be necessary to conditionalize declarations to meet -different requirements. For example we might want a bit string whose length -is set to meet some hardware message requirement. +@display +@emph{Operand size}@w{ } +@display +gcc / @emph{as}: Explicit in op code; for example @cite{movw} to move a 16-bit word@w{ } +Intel: Implicit, deduced by assembler; for example @cite{mov}@w{ } +@end display +@end display -In some cases, it may be possible to do this using declare blocks controlled -by conditional constants: -@smallexample @c ada -@group -@b{if} Small_Machine @b{then} - @b{declare} - X : Bit_String (1 .. 10); - @b{begin} - @dots{} - @b{end}; -@b{else} - @b{declare} - X : Large_Bit_String (1 .. 1000); - @b{begin} - @dots{} - @b{end}; -@b{end} @b{if}; -@end group -@end smallexample - -@noindent -Note that in this approach, both declarations are analyzed by the -compiler so this can only be used where both declarations are legal, -even though one of them will not be used. - -Another approach is to define integer constants, e.g.@: @code{Bits_Per_Word}, -or Boolean constants, e.g.@: @code{Little_Endian}, and then write declarations -that are parameterized by these constants. For example - -@smallexample @c ada -@group -@b{for} Rec @b{use} - Field1 @b{at} 0 @b{range} Boolean'Pos (Little_Endian) * 10 .. Bits_Per_Word; -@b{end} @b{record}; -@end group -@end smallexample - -@noindent -If @code{Bits_Per_Word} is set to 32, this generates either - -@smallexample @c ada -@group -@b{for} Rec @b{use} - Field1 @b{at} 0 @b{range} 0 .. 32; -@b{end} @b{record}; -@end group -@end smallexample - -@noindent -for the big endian case, or - -@smallexample @c ada -@group -@b{for} Rec @b{use} @b{record} - Field1 @b{at} 0 @b{range} 10 .. 32; -@b{end} @b{record}; -@end group -@end smallexample - -@noindent -for the little endian case. Since a powerful subset of Ada expression -notation is usable for creating static constants, clever use of this -feature can often solve quite difficult problems in conditionalizing -compilation (note incidentally that in Ada 95, the little endian -constant was introduced as @code{System.Default_Bit_Order}, so you do not -need to define this one yourself). - - -@node Use of Alternative Implementations -@section Use of Alternative Implementations - -@noindent -In some cases, none of the approaches described above are adequate. This -can occur for example if the set of declarations required is radically -different for two different configurations. - -In this situation, the official Ada way of dealing with conditionalizing -such code is to write separate units for the different cases. As long as -this does not result in excessive duplication of code, this can be done -without creating maintenance problems. The approach is to share common -code as far as possible, and then isolate the code and declarations -that are different. Subunits are often a convenient method for breaking -out a piece of a unit that is to be conditionalized, with separate files -for different versions of the subunit for different targets, where the -build script selects the right one to give to the compiler. -@cindex Subunits (and conditional compilation) - -As an example, consider a situation where a new feature in Ada 2005 -allows something to be done in a really nice way. But your code must be able -to compile with an Ada 95 compiler. Conceptually you want to say: -@smallexample @c ada -@group -@b{if} Ada_2005 @b{then} - @dots{} neat Ada 2005 code -@b{else} - @dots{} not quite as neat Ada 95 code -@b{end} @b{if}; -@end group -@end smallexample - -@noindent -where @code{Ada_2005} is a Boolean constant. - -But this won't work when @code{Ada_2005} is set to @code{False}, -since the @code{then} clause will be illegal for an Ada 95 compiler. -(Recall that although such unreachable code would eventually be deleted -by the compiler, it still needs to be legal. If it uses features -introduced in Ada 2005, it will be illegal in Ada 95.) - -So instead we write -@smallexample @c ada -@b{procedure} Insert @b{is} @b{separate}; -@end smallexample +@display +@emph{Instruction repetition}@w{ } +@display +gcc / @emph{as}: Split into two lines; for example@w{ } +@display +@cite{rep}@w{ } +@cite{stosl}@w{ } +@end display +Intel: Keep on one line; for example @cite{rep stosl}@w{ } +@end display +@end display -@noindent -Then we have two files for the subunit @code{Insert}, with the two sets of -code. -If the package containing this is called @code{File_Queries}, then we might -have two files -@itemize @bullet -@item @file{file_queries-insert-2005.adb} -@item @file{file_queries-insert-95.adb} -@end itemize -@noindent -and the build script renames the appropriate file to -@smallexample -file_queries-insert.adb -@end smallexample +@display +@emph{Order of operands}@w{ } +@display +gcc / @emph{as}: Source first; for example @cite{movw $4@comma{} %eax}@w{ } +Intel: Destination first; for example @cite{mov eax@comma{} 4}@w{ } +@end display +@end display -@noindent -and then carries out the compilation. -This can also be done with project files' naming schemes. For example: -@smallexample @c project -For Body ("File_Queries.Insert") use "file_queries-insert-2005.ada"; -@end smallexample +@node A Simple Example of Inline Assembler,Output Variables in Inline Assembler,Basic Assembler Syntax,Inline Assembler +@anchor{gnat_ugn/inline_assembler a-simple-example-of-inline-assembler}@anchor{2d0}@anchor{gnat_ugn/inline_assembler id3}@anchor{2d1} +@section A Simple Example of Inline Assembler -@noindent -Note also that with project files it is desirable to use a different extension -than @file{ads} / @file{adb} for alternative versions. Otherwise a naming -conflict may arise through another commonly used feature: to declare as part -of the project a set of directories containing all the sources obeying the -default naming scheme. -The use of alternative units is certainly feasible in all situations, -and for example the Ada part of the GNAT run-time is conditionalized -based on the target architecture using this approach. As a specific example, -consider the implementation of the AST feature in VMS. There is one -spec: +The following example will generate a single assembly language statement, +@cite{nop}, which does nothing. Despite its lack of run-time effect, +the example will be useful in illustrating the basics of +the Inline Assembler facility. -@smallexample -s-asthan.ads -@end smallexample +@quotation -@noindent -which is the same for all architectures, and three bodies: +@example +with System.Machine_Code; use System.Machine_Code; +procedure Nothing is +begin + Asm ("nop"); +end Nothing; +@end example +@end quotation -@table @file -@item s-asthan.adb -used for all non-VMS operating systems -@item s-asthan-vms-alpha.adb -used for VMS on the Alpha -@item s-asthan-vms-ia64.adb -used for VMS on the ia64 -@end table +@cite{Asm} is a procedure declared in package @cite{System.Machine_Code}; +here it takes one parameter, a @emph{template string} that must be a static +expression and that will form the generated instruction. +@cite{Asm} may be regarded as a compile-time procedure that parses +the template string and additional parameters (none here), +from which it generates a sequence of assembly language instructions. -@noindent -The dummy version @file{s-asthan.adb} simply raises exceptions noting that -this operating system feature is not available, and the two remaining -versions interface with the corresponding versions of VMS to provide -VMS-compatible AST handling. The GNAT build script knows the architecture -and operating system, and automatically selects the right version, -renaming it if necessary to @file{s-asthan.adb} before the run-time build. +The examples in this chapter will illustrate several of the forms +for invoking @cite{Asm}; a complete specification of the syntax +is found in the @cite{Machine_Code_Insertions} section of the +@cite{GNAT Reference Manual}. -Another style for arranging alternative implementations is through Ada's -access-to-subprogram facility. -In case some functionality is to be conditionally included, -you can declare an access-to-procedure variable @code{Ref} that is initialized -to designate a ``do nothing'' procedure, and then invoke @code{Ref.all} -when appropriate. -In some library package, set @code{Ref} to @code{Proc'Access} for some -procedure @code{Proc} that performs the relevant processing. -The initialization only occurs if the library package is included in the -program. -The same idea can also be implemented using tagged types and dispatching -calls. +Under the standard GNAT conventions, the @cite{Nothing} procedure +should be in a file named @code{nothing.adb}. +You can build the executable in the usual way: +@quotation -@node Preprocessing -@section Preprocessing -@cindex Preprocessing +@example +$ gnatmake nothing +@end example +@end quotation -@noindent -Although it is quite possible to conditionalize code without the use of -C-style preprocessing, as described earlier in this section, it is -nevertheless convenient in some cases to use the C approach. Moreover, -older Ada compilers have often provided some preprocessing capability, -so legacy code may depend on this approach, even though it is not -standard. +However, the interesting aspect of this example is not its run-time behavior +but rather the generated assembly code. +To see this output, invoke the compiler as follows: -To accommodate such use, GNAT provides a preprocessor (modeled to a large -extent on the various preprocessors that have been used -with legacy code on other compilers, to enable easier transition). +@quotation -The preprocessor may be used in two separate modes. It can be used quite -separately from the compiler, to generate a separate output source file -that is then fed to the compiler as a separate step. This is the -@code{gnatprep} utility, whose use is fully described in -@ref{Preprocessing with gnatprep}. -@cindex @code{gnatprep} +@example +$ gcc -c -S -fomit-frame-pointer -gnatp nothing.adb +@end example +@end quotation -The preprocessing language allows such constructs as +where the options are: -@smallexample -@group -#if DEBUG or else (PRIORITY > 4) then - bunch of declarations -#else - completely different bunch of declarations -#end if; -@end group -@end smallexample -@noindent -The values of the symbols @code{DEBUG} and @code{PRIORITY} can be -defined either on the command line or in a separate file. +@itemize * -The other way of running the preprocessor is even closer to the C style and -often more convenient. In this approach the preprocessing is integrated into -the compilation process. The compiler is fed the preprocessor input which -includes @code{#if} lines etc, and then the compiler carries out the -preprocessing internally and processes the resulting output. -For more details on this approach, see @ref{Integrated Preprocessing}. +@item +@table @asis -@c ******************************* -@node Inline Assembler -@appendix Inline Assembler -@c ******************************* +@item @code{-c} -@noindent -If you need to write low-level software that interacts directly -with the hardware, Ada provides two ways to incorporate assembly -language code into your program. First, you can import and invoke -external routines written in assembly language, an Ada feature fully -supported by GNAT@. However, for small sections of code it may be simpler -or more efficient to include assembly language statements directly -in your Ada source program, using the facilities of the implementation-defined -package @code{System.Machine_Code}, which incorporates the gcc -Inline Assembler. The Inline Assembler approach offers a number of advantages, -including the following: +compile only (no bind or link) +@end table -@itemize @bullet -@item No need to use non-Ada tools -@item Consistent interface over different targets -@item Automatic usage of the proper calling conventions -@item Access to Ada constants and variables -@item Definition of intrinsic routines -@item Possibility of inlining a subprogram comprising assembler code -@item Code optimizer can take Inline Assembler code into account -@end itemize +@item -This chapter presents a series of examples to show you how to use -the Inline Assembler. Although it focuses on the Intel x86, -the general approach applies also to other processors. -It is assumed that you are familiar with Ada -and with assembly language programming. +@table @asis -@menu -* Basic Assembler Syntax:: -* A Simple Example of Inline Assembler:: -* Output Variables in Inline Assembler:: -* Input Variables in Inline Assembler:: -* Inlining Inline Assembler Code:: -* Other Asm Functionality:: -@end menu +@item @code{-S} -@c --------------------------------------------------------------------------- -@node Basic Assembler Syntax -@section Basic Assembler Syntax +generate assembler listing +@end table -@noindent -The assembler used by GNAT and gcc is based not on the Intel assembly -language, but rather on a language that descends from the AT&T Unix -assembler @emph{as} (and which is often referred to as ``AT&T syntax''). -The following table summarizes the main features of @emph{as} syntax -and points out the differences from the Intel conventions. -See the gcc @emph{as} and @emph{gas} (an @emph{as} macro -pre-processor) documentation for further information. +@item @table @asis -@item Register names -gcc / @emph{as}: Prefix with ``%''; for example @code{%eax} -@* -Intel: No extra punctuation; for example @code{eax} - -@item Immediate operand -gcc / @emph{as}: Prefix with ``$''; for example @code{$4} -@* -Intel: No extra punctuation; for example @code{4} - -@item Address -gcc / @emph{as}: Prefix with ``$''; for example @code{$loc} -@* -Intel: No extra punctuation; for example @code{loc} - -@item Memory contents -gcc / @emph{as}: No extra punctuation; for example @code{loc} -@* -Intel: Square brackets; for example @code{[loc]} - -@item Register contents -gcc / @emph{as}: Parentheses; for example @code{(%eax)} -@* -Intel: Square brackets; for example @code{[eax]} - -@item Hexadecimal numbers -gcc / @emph{as}: Leading ``0x'' (C language syntax); for example @code{0xA0} -@* -Intel: Trailing ``h''; for example @code{A0h} - -@item Operand size -gcc / @emph{as}: Explicit in op code; for example @code{movw} to move -a 16-bit word -@* -Intel: Implicit, deduced by assembler; for example @code{mov} - -@item Instruction repetition -gcc / @emph{as}: Split into two lines; for example -@* -@code{rep} -@* -@code{stosl} -@* -Intel: Keep on one line; for example @code{rep stosl} - -@item Order of operands -gcc / @emph{as}: Source first; for example @code{movw $4, %eax} -@* -Intel: Destination first; for example @code{mov eax, 4} -@end table - -@c --------------------------------------------------------------------------- -@node A Simple Example of Inline Assembler -@section A Simple Example of Inline Assembler -@noindent -The following example will generate a single assembly language statement, -@code{nop}, which does nothing. Despite its lack of run-time effect, -the example will be useful in illustrating the basics of -the Inline Assembler facility. +@item @code{-fomit-frame-pointer} -@smallexample @c ada -@group -@b{with} System.Machine_Code; @b{use} System.Machine_Code; -@b{procedure} Nothing @b{is} -@b{begin} - Asm ("nop"); -@b{end} Nothing; -@end group -@end smallexample +do not set up separate stack frames +@end table -@code{Asm} is a procedure declared in package @code{System.Machine_Code}; -here it takes one parameter, a @emph{template string} that must be a static -expression and that will form the generated instruction. -@code{Asm} may be regarded as a compile-time procedure that parses -the template string and additional parameters (none here), -from which it generates a sequence of assembly language instructions. +@item -The examples in this chapter will illustrate several of the forms -for invoking @code{Asm}; a complete specification of the syntax -is found in @ref{Machine Code Insertions,,, gnat_rm, GNAT Reference -Manual}. +@table @asis -Under the standard GNAT conventions, the @code{Nothing} procedure -should be in a file named @file{nothing.adb}. -You can build the executable in the usual way: -@smallexample -gnatmake nothing -@end smallexample -However, the interesting aspect of this example is not its run-time behavior -but rather the generated assembly code. -To see this output, invoke the compiler as follows: -@smallexample - gcc -c -S -fomit-frame-pointer -gnatp @file{nothing.adb} -@end smallexample -where the options are: +@item @code{-gnatp} -@table @code -@item -c -compile only (no bind or link) -@item -S -generate assembler listing -@item -fomit-frame-pointer -do not set up separate stack frames -@item -gnatp do not add runtime checks @end table +@end itemize This gives a human-readable assembler version of the code. The resulting -file will have the same name as the Ada source file, but with a @code{.s} -extension. In our example, the file @file{nothing.s} has the following +file will have the same name as the Ada source file, but with a @cite{.s} +extension. In our example, the file @code{nothing.s} has the following contents: -@smallexample -@group +@quotation + +@example .file "nothing.adb" gcc2_compiled.: ___gnu_compiled_ada: @@ -26157,11 +35100,11 @@ __ada_nothing: .align 2,0x90 L1: ret -@end group -@end smallexample +@end example +@end quotation The assembly code you included is clearly indicated by -the compiler, between the @code{#APP} and @code{#NO_APP} +the compiler, between the @cite{#APP} and @cite{#NO_APP} delimiters. The character before the 'APP' and 'NOAPP' can differ on different targets. For example, GNU/Linux uses '#APP' while on NT you will see '/APP'. @@ -26175,70 +35118,81 @@ in such cases, since you can assemble this file separately using the Assembling the file using the command -@smallexample -as @file{nothing.s} -@end smallexample -@noindent +@quotation + +@example +$ as nothing.s +@end example +@end quotation + will give you error messages whose lines correspond to the assembler input file, so you can easily find and correct any mistakes you made. If there are no errors, @emph{as} will generate an object file -@file{nothing.out}. +@code{nothing.out}. -@c --------------------------------------------------------------------------- -@node Output Variables in Inline Assembler +@node Output Variables in Inline Assembler,Input Variables in Inline Assembler,A Simple Example of Inline Assembler,Inline Assembler +@anchor{gnat_ugn/inline_assembler id4}@anchor{2d2}@anchor{gnat_ugn/inline_assembler output-variables-in-inline-assembler}@anchor{2d3} @section Output Variables in Inline Assembler -@noindent + The examples in this section, showing how to access the processor flags, illustrate how to specify the destination operands for assembly language statements. -@smallexample @c ada -@group -@b{with} Interfaces; @b{use} Interfaces; -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{with} System.Machine_Code; @b{use} System.Machine_Code; -@b{procedure} Get_Flags @b{is} +@quotation + +@example +with Interfaces; use Interfaces; +with Ada.Text_IO; use Ada.Text_IO; +with System.Machine_Code; use System.Machine_Code; +procedure Get_Flags is Flags : Unsigned_32; - @b{use} ASCII; -@b{begin} - Asm ("pushfl" & LF & HT & --@i{ push flags on stack} - "popl %%eax" & LF & HT & --@i{ load eax with flags} - "movl %%eax, %0", --@i{ store flags in variable} + use ASCII; +begin + Asm ("pushfl" & LF & HT & -- push flags on stack + "popl %%eax" & LF & HT & -- load eax with flags + "movl %%eax, %0", -- store flags in variable Outputs => Unsigned_32'Asm_Output ("=g", Flags)); Put_Line ("Flags register:" & Flags'Img); -@b{end} Get_Flags; -@end group -@end smallexample +end Get_Flags; +@end example +@end quotation In order to have a nicely aligned assembly listing, we have separated multiple assembler statements in the Asm template string with linefeed (ASCII.LF) and horizontal tab (ASCII.HT) characters. The resulting section of the assembly output file is: -@smallexample -@group +@quotation + +@example #APP pushfl popl %eax movl %eax, -40(%ebp) #NO_APP -@end group -@end smallexample +@end example +@end quotation It would have been legal to write the Asm invocation as: -@smallexample +@quotation + +@example Asm ("pushfl popl %%eax movl %%eax, %0") -@end smallexample +@end example +@end quotation but in the generated assembler file, this would come out as: -@smallexample +@quotation + +@example #APP pushfl popl %eax movl %eax, -40(%ebp) #NO_APP -@end smallexample +@end example +@end quotation which is not so convenient for the human reader. @@ -26249,234 +35203,344 @@ actually do. This is a useful convention. When writing Inline Assembler instructions, you need to precede each register and variable name with a percent sign. Since the assembler already requires a percent sign at the beginning of a register name, you need two consecutive -percent signs for such names in the Asm template string, thus @code{%%eax}. +percent signs for such names in the Asm template string, thus @cite{%%eax}. In the generated assembly code, one of the percent signs will be stripped off. -Names such as @code{%0}, @code{%1}, @code{%2}, etc., denote input or output -variables: operands you later define using @code{Input} or @code{Output} -parameters to @code{Asm}. +Names such as @cite{%0}, @cite{%1}, @cite{%2}, etc., denote input or output +variables: operands you later define using @cite{Input} or @cite{Output} +parameters to @cite{Asm}. An output variable is illustrated in the third statement in the Asm template string: -@smallexample + +@quotation + +@example movl %%eax, %0 -@end smallexample +@end example +@end quotation + The intent is to store the contents of the eax register in a variable that can -be accessed in Ada. Simply writing @code{movl %%eax, Flags} would not +be accessed in Ada. Simply writing @cite{movl %%eax@comma{} Flags} would not necessarily work, since the compiler might optimize by using a register -to hold Flags, and the expansion of the @code{movl} instruction would not be +to hold Flags, and the expansion of the @cite{movl} instruction would not be aware of this optimization. The solution is not to store the result directly but rather to advise the compiler to choose the correct operand form; -that is the purpose of the @code{%0} output variable. +that is the purpose of the @cite{%0} output variable. + +Information about the output variable is supplied in the @cite{Outputs} +parameter to @cite{Asm}: + +@quotation -Information about the output variable is supplied in the @code{Outputs} -parameter to @code{Asm}: -@smallexample +@example Outputs => Unsigned_32'Asm_Output ("=g", Flags)); -@end smallexample +@end example +@end quotation -The output is defined by the @code{Asm_Output} attribute of the target type; +The output is defined by the @cite{Asm_Output} attribute of the target type; the general format is -@smallexample + +@quotation + +@example Type'Asm_Output (constraint_string, variable_name) -@end smallexample +@end example +@end quotation The constraint string directs the compiler how to store/access the associated variable. In the example -@smallexample + +@quotation + +@example Unsigned_32'Asm_Output ("=m", Flags); -@end smallexample -the @code{"m"} (memory) constraint tells the compiler that the variable -@code{Flags} should be stored in a memory variable, thus preventing +@end example +@end quotation + +the @cite{"m"} (memory) constraint tells the compiler that the variable +@cite{Flags} should be stored in a memory variable, thus preventing the optimizer from keeping it in a register. In contrast, -@smallexample + +@quotation + +@example Unsigned_32'Asm_Output ("=r", Flags); -@end smallexample -uses the @code{"r"} (register) constraint, telling the compiler to +@end example +@end quotation + +uses the @cite{"r"} (register) constraint, telling the compiler to store the variable in a register. -If the constraint is preceded by the equal character (@strong{=}), it tells +If the constraint is preceded by the equal character '=', it tells the compiler that the variable will be used to store data into it. -In the @code{Get_Flags} example, we used the @code{"g"} (global) constraint, +In the @cite{Get_Flags} example, we used the @cite{"g"} (global) constraint, allowing the optimizer to choose whatever it deems best. There are a fairly large number of constraints, but the ones that are most useful (for the Intel x86 processor) are the following: -@table @code -@item = +@quotation + + +@multitable {xxxxxxxx} {xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx} +@item + +@emph{=} + +@tab + output constraint -@item g -global (i.e.@: can be stored anywhere) -@item m + +@item + +@emph{g} + +@tab + +global (i.e., can be stored anywhere) + +@item + +@emph{m} + +@tab + in memory -@item I + +@item + +@emph{I} + +@tab + a constant -@item a + +@item + +@emph{a} + +@tab + use eax -@item b + +@item + +@emph{b} + +@tab + use ebx -@item c + +@item + +@emph{c} + +@tab + use ecx -@item d + +@item + +@emph{d} + +@tab + use edx -@item S + +@item + +@emph{S} + +@tab + use esi -@item D + +@item + +@emph{D} + +@tab + use edi -@item r + +@item + +@emph{r} + +@tab + use one of eax, ebx, ecx or edx -@item q + +@item + +@emph{q} + +@tab + use one of eax, ebx, ecx, edx, esi or edi -@end table + +@end multitable + +@end quotation The full set of constraints is described in the gcc and @emph{as} documentation; note that it is possible to combine certain constraints in one constraint string. You specify the association of an output variable with an assembler operand -through the @code{%}@emph{n} notation, where @emph{n} is a non-negative +through the @code{%@emph{n}} notation, where @emph{n} is a non-negative integer. Thus in -@smallexample @c ada -@group -Asm ("pushfl" & LF & HT & --@i{ push flags on stack} - "popl %%eax" & LF & HT & --@i{ load eax with flags} - "movl %%eax, %0", --@i{ store flags in variable} + +@quotation + +@example +Asm ("pushfl" & LF & HT & -- push flags on stack + "popl %%eax" & LF & HT & -- load eax with flags + "movl %%eax, %0", -- store flags in variable Outputs => Unsigned_32'Asm_Output ("=g", Flags)); -@end group -@end smallexample -@noindent -@code{%0} will be replaced in the expanded code by the appropriate operand, +@end example +@end quotation + +@cite{%0} will be replaced in the expanded code by the appropriate operand, whatever -the compiler decided for the @code{Flags} variable. +the compiler decided for the @cite{Flags} variable. In general, you may have any number of output variables: -@itemize @bullet -@item -Count the operands starting at 0; thus @code{%0}, @code{%1}, etc. -@item -Specify the @code{Outputs} parameter as a parenthesized comma-separated list -of @code{Asm_Output} attributes + + +@itemize * + +@item +Count the operands starting at 0; thus @cite{%0}, @cite{%1}, etc. + +@item +Specify the @cite{Outputs} parameter as a parenthesized comma-separated list +of @cite{Asm_Output} attributes @end itemize For example: -@smallexample @c ada -@group + +@quotation + +@example Asm ("movl %%eax, %0" & LF & HT & "movl %%ebx, %1" & LF & HT & "movl %%ecx, %2", - Outputs => (Unsigned_32'Asm_Output ("=g", Var_A), --@i{ %0 = Var_A} - Unsigned_32'Asm_Output ("=g", Var_B), --@i{ %1 = Var_B} - Unsigned_32'Asm_Output ("=g", Var_C))); --@i{ %2 = Var_C} -@end group -@end smallexample -@noindent -where @code{Var_A}, @code{Var_B}, and @code{Var_C} are variables + Outputs => (Unsigned_32'Asm_Output ("=g", Var_A), -- %0 = Var_A + Unsigned_32'Asm_Output ("=g", Var_B), -- %1 = Var_B + Unsigned_32'Asm_Output ("=g", Var_C))); -- %2 = Var_C +@end example +@end quotation + +where @cite{Var_A}, @cite{Var_B}, and @cite{Var_C} are variables in the Ada program. -As a variation on the @code{Get_Flags} example, we can use the constraints -string to direct the compiler to store the eax register into the @code{Flags} +As a variation on the @cite{Get_Flags} example, we can use the constraints +string to direct the compiler to store the eax register into the @cite{Flags} variable, instead of including the store instruction explicitly in the -@code{Asm} template string: - -@smallexample @c ada -@group -@b{with} Interfaces; @b{use} Interfaces; -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{with} System.Machine_Code; @b{use} System.Machine_Code; -@b{procedure} Get_Flags_2 @b{is} +@cite{Asm} template string: + +@quotation + +@example +with Interfaces; use Interfaces; +with Ada.Text_IO; use Ada.Text_IO; +with System.Machine_Code; use System.Machine_Code; +procedure Get_Flags_2 is Flags : Unsigned_32; - @b{use} ASCII; -@b{begin} - Asm ("pushfl" & LF & HT & --@i{ push flags on stack} - "popl %%eax", --@i{ save flags in eax} + use ASCII; +begin + Asm ("pushfl" & LF & HT & -- push flags on stack + "popl %%eax", -- save flags in eax Outputs => Unsigned_32'Asm_Output ("=a", Flags)); Put_Line ("Flags register:" & Flags'Img); -@b{end} Get_Flags_2; -@end group -@end smallexample +end Get_Flags_2; +@end example +@end quotation -@noindent -The @code{"a"} constraint tells the compiler that the @code{Flags} +The @cite{"a"} constraint tells the compiler that the @cite{Flags} variable will come from the eax register. Here is the resulting code: -@smallexample -@group +@quotation + +@example #APP pushfl popl %eax #NO_APP movl %eax,-40(%ebp) -@end group -@end smallexample +@end example +@end quotation -@noindent The compiler generated the store of eax into Flags after expanding the assembler code. Actually, there was no need to pop the flags into the eax register; more simply, we could just pop the flags directly into the program variable: -@smallexample @c ada -@group -@b{with} Interfaces; @b{use} Interfaces; -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{with} System.Machine_Code; @b{use} System.Machine_Code; -@b{procedure} Get_Flags_3 @b{is} +@quotation + +@example +with Interfaces; use Interfaces; +with Ada.Text_IO; use Ada.Text_IO; +with System.Machine_Code; use System.Machine_Code; +procedure Get_Flags_3 is Flags : Unsigned_32; - @b{use} ASCII; -@b{begin} - Asm ("pushfl" & LF & HT & --@i{ push flags on stack} - "pop %0", --@i{ save flags in Flags} + use ASCII; +begin + Asm ("pushfl" & LF & HT & -- push flags on stack + "pop %0", -- save flags in Flags Outputs => Unsigned_32'Asm_Output ("=g", Flags)); Put_Line ("Flags register:" & Flags'Img); -@b{end} Get_Flags_3; -@end group -@end smallexample +end Get_Flags_3; +@end example +@end quotation -@c --------------------------------------------------------------------------- -@node Input Variables in Inline Assembler +@node Input Variables in Inline Assembler,Inlining Inline Assembler Code,Output Variables in Inline Assembler,Inline Assembler +@anchor{gnat_ugn/inline_assembler id5}@anchor{2d4}@anchor{gnat_ugn/inline_assembler input-variables-in-inline-assembler}@anchor{2d5} @section Input Variables in Inline Assembler -@noindent + The example in this section illustrates how to specify the source operands for assembly language statements. The program simply increments its input value by 1: -@smallexample @c ada -@group -@b{with} Interfaces; @b{use} Interfaces; -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{with} System.Machine_Code; @b{use} System.Machine_Code; -@b{procedure} Increment @b{is} +@quotation + +@example +with Interfaces; use Interfaces; +with Ada.Text_IO; use Ada.Text_IO; +with System.Machine_Code; use System.Machine_Code; +procedure Increment is - @b{function} Incr (Value : Unsigned_32) @b{return} Unsigned_32 @b{is} + function Incr (Value : Unsigned_32) return Unsigned_32 is Result : Unsigned_32; - @b{begin} + begin Asm ("incl %0", Outputs => Unsigned_32'Asm_Output ("=a", Result), Inputs => Unsigned_32'Asm_Input ("a", Value)); - @b{return} Result; - @b{end} Incr; + return Result; + end Incr; Value : Unsigned_32; -@b{begin} +begin Value := 5; Put_Line ("Value before is" & Value'Img); Value := Incr (Value); - Put_Line ("Value after is" & Value'Img); -@b{end} Increment; -@end group -@end smallexample + Put_Line ("Value after is" & Value'Img); +end Increment; +@end example +@end quotation -The @code{Outputs} parameter to @code{Asm} specifies +The @cite{Outputs} parameter to @cite{Asm} specifies that the result will be in the eax register and that it is to be stored -in the @code{Result} variable. +in the @cite{Result} variable. -The @code{Inputs} parameter looks much like the @code{Outputs} parameter, -but with an @code{Asm_Input} attribute. -The @code{"="} constraint, indicating an output value, is not present. +The @cite{Inputs} parameter looks much like the @cite{Outputs} parameter, +but with an @cite{Asm_Input} attribute. +The @cite{"="} constraint, indicating an output value, is not present. You can have multiple input variables, in the same way that you can have more than one output variable. @@ -26484,21 +35548,31 @@ than one output variable. The parameter count (%0, %1) etc, still starts at the first output statement, and continues with the input statements. -Just as the @code{Outputs} parameter causes the register to be stored into the +Just as the @cite{Outputs} parameter causes the register to be stored into the target variable after execution of the assembler statements, so does the -@code{Inputs} parameter cause its variable to be loaded into the register +@cite{Inputs} parameter cause its variable to be loaded into the register before execution of the assembler statements. -Thus the effect of the @code{Asm} invocation is: -@enumerate -@item load the 32-bit value of @code{Value} into eax -@item execute the @code{incl %eax} instruction -@item store the contents of eax into the @code{Result} variable -@end enumerate +Thus the effect of the @cite{Asm} invocation is: + + +@itemize * + +@item +load the 32-bit value of @cite{Value} into eax + +@item +execute the @cite{incl %eax} instruction + +@item +store the contents of eax into the @cite{Result} variable +@end itemize + +The resulting assembler file (with @emph{-O2} optimization) contains: -The resulting assembler file (with @option{-O2} optimization) contains: -@smallexample -@group +@quotation + +@example _increment__incr.1: subl $4,%esp movl 8(%esp),%eax @@ -26509,3050 +35583,684 @@ _increment__incr.1: movl %ecx,(%esp) addl $4,%esp ret -@end group -@end smallexample +@end example +@end quotation -@c --------------------------------------------------------------------------- -@node Inlining Inline Assembler Code +@node Inlining Inline Assembler Code,Other Asm Functionality,Input Variables in Inline Assembler,Inline Assembler +@anchor{gnat_ugn/inline_assembler id6}@anchor{2d6}@anchor{gnat_ugn/inline_assembler inlining-inline-assembler-code}@anchor{2d7} @section Inlining Inline Assembler Code -@noindent -For a short subprogram such as the @code{Incr} function in the previous + +For a short subprogram such as the @cite{Incr} function in the previous section, the overhead of the call and return (creating / deleting the stack frame) can be significant, compared to the amount of code in the subprogram -body. A solution is to apply Ada's @code{Inline} pragma to the subprogram, +body. A solution is to apply Ada's @cite{Inline} pragma to the subprogram, which directs the compiler to expand invocations of the subprogram at the point(s) of call, instead of setting up a stack frame for out-of-line calls. Here is the resulting program: -@smallexample @c ada -@group -@b{with} Interfaces; @b{use} Interfaces; -@b{with} Ada.Text_IO; @b{use} Ada.Text_IO; -@b{with} System.Machine_Code; @b{use} System.Machine_Code; -@b{procedure} Increment_2 @b{is} +@quotation + +@example +with Interfaces; use Interfaces; +with Ada.Text_IO; use Ada.Text_IO; +with System.Machine_Code; use System.Machine_Code; +procedure Increment_2 is - @b{function} Incr (Value : Unsigned_32) @b{return} Unsigned_32 @b{is} + function Incr (Value : Unsigned_32) return Unsigned_32 is Result : Unsigned_32; - @b{begin} + begin Asm ("incl %0", Outputs => Unsigned_32'Asm_Output ("=a", Result), Inputs => Unsigned_32'Asm_Input ("a", Value)); - @b{return} Result; - @b{end} Incr; - @b{pragma} Inline (Increment); + return Result; + end Incr; + pragma Inline (Increment); Value : Unsigned_32; -@b{begin} +begin Value := 5; Put_Line ("Value before is" & Value'Img); Value := Increment (Value); Put_Line ("Value after is" & Value'Img); -@b{end} Increment_2; -@end group -@end smallexample +end Increment_2; +@end example +@end quotation + +Compile the program with both optimization (@emph{-O2}) and inlining +(@emph{-gnatn}) enabled. -Compile the program with both optimization (@option{-O2}) and inlining -(@option{-gnatn}) enabled. +The @cite{Incr} function is still compiled as usual, but at the +point in @cite{Increment} where our function used to be called: -The @code{Incr} function is still compiled as usual, but at the -point in @code{Increment} where our function used to be called: +@quotation -@smallexample -@group +@example pushl %edi call _increment__incr.1 -@end group -@end smallexample +@end example +@end quotation -@noindent the code for the function body directly appears: -@smallexample -@group +@quotation + +@example movl %esi,%eax #APP incl %eax #NO_APP movl %eax,%edx -@end group -@end smallexample +@end example +@end quotation -@noindent thus saving the overhead of stack frame setup and an out-of-line call. -@c --------------------------------------------------------------------------- -@node Other Asm Functionality -@section Other @code{Asm} Functionality +@node Other Asm Functionality,,Inlining Inline Assembler Code,Inline Assembler +@anchor{gnat_ugn/inline_assembler other-asm-functionality}@anchor{2d8}@anchor{gnat_ugn/inline_assembler id7}@anchor{2d9} +@section Other @cite{Asm} Functionality + -@noindent -This section describes two important parameters to the @code{Asm} -procedure: @code{Clobber}, which identifies register usage; -and @code{Volatile}, which inhibits unwanted optimizations. +This section describes two important parameters to the @cite{Asm} +procedure: @cite{Clobber}, which identifies register usage; +and @cite{Volatile}, which inhibits unwanted optimizations. @menu -* The Clobber Parameter:: -* The Volatile Parameter:: +* The Clobber Parameter:: +* The Volatile Parameter:: + @end menu -@c --------------------------------------------------------------------------- -@node The Clobber Parameter -@subsection The @code{Clobber} Parameter +@node The Clobber Parameter,The Volatile Parameter,,Other Asm Functionality +@anchor{gnat_ugn/inline_assembler the-clobber-parameter}@anchor{2da}@anchor{gnat_ugn/inline_assembler id8}@anchor{2db} +@subsection The @cite{Clobber} Parameter + -@noindent One of the dangers of intermixing assembly language and a compiled language such as Ada is that the compiler needs to be aware of which registers are being used by the assembly code. In some cases, such as the earlier examples, the constraint string is sufficient to indicate register usage (e.g., -@code{"a"} for +@cite{"a"} for the eax register). But more generally, the compiler needs an explicit identification of the registers that are used by the Inline Assembly statements. Using a register that the compiler doesn't know about -could be a side effect of an instruction (like @code{mull} +could be a side effect of an instruction (like @cite{mull} storing its result in both eax and edx). It can also arise from explicit register usage in your assembly code; for example: -@smallexample -@group + +@quotation + +@example Asm ("movl %0, %%ebx" & LF & HT & "movl %%ebx, %1", Outputs => Unsigned_32'Asm_Output ("=g", Var_Out), Inputs => Unsigned_32'Asm_Input ("g", Var_In)); -@end group -@end smallexample -@noindent -where the compiler (since it does not analyze the @code{Asm} template string) +@end example +@end quotation + +where the compiler (since it does not analyze the @cite{Asm} template string) does not know you are using the ebx register. -In such cases you need to supply the @code{Clobber} parameter to @code{Asm}, +In such cases you need to supply the @cite{Clobber} parameter to @cite{Asm}, to identify the registers that will be used by your assembly code: -@smallexample -@group +@quotation + +@example Asm ("movl %0, %%ebx" & LF & HT & "movl %%ebx, %1", Outputs => Unsigned_32'Asm_Output ("=g", Var_Out), Inputs => Unsigned_32'Asm_Input ("g", Var_In), Clobber => "ebx"); -@end group -@end smallexample +@end example +@end quotation The Clobber parameter is a static string expression specifying the register(s) you are using. Note that register names are @emph{not} prefixed by a percent sign. Also, if more than one register is used then their names -are separated by commas; e.g., @code{"eax, ebx"} +are separated by commas; e.g., @cite{"eax@comma{} ebx"} -The @code{Clobber} parameter has several additional uses: -@enumerate -@item Use ``register'' name @code{cc} to indicate that flags might have changed -@item Use ``register'' name @code{memory} if you changed a memory location -@end enumerate +The @cite{Clobber} parameter has several additional uses: + + +@itemize * + +@item +Use 'register' name @cite{cc} to indicate that flags might have changed + +@item +Use 'register' name @cite{memory} if you changed a memory location +@end itemize -@c --------------------------------------------------------------------------- -@node The Volatile Parameter -@subsection The @code{Volatile} Parameter -@cindex Volatile parameter +@node The Volatile Parameter,,The Clobber Parameter,Other Asm Functionality +@anchor{gnat_ugn/inline_assembler the-volatile-parameter}@anchor{2dc}@anchor{gnat_ugn/inline_assembler id9}@anchor{2dd} +@subsection The @cite{Volatile} Parameter + + +@geindex Volatile parameter -@noindent Compiler optimizations in the presence of Inline Assembler may sometimes have -unwanted effects. For example, when an @code{Asm} invocation with an input +unwanted effects. For example, when an @cite{Asm} invocation with an input variable is inside a loop, the compiler might move the loading of the input variable outside the loop, regarding it as a one-time initialization. If this effect is not desired, you can disable such optimizations by setting -the @code{Volatile} parameter to @code{True}; for example: +the @cite{Volatile} parameter to @cite{True}; for example: + +@quotation -@smallexample @c ada -@group +@example Asm ("movl %0, %%ebx" & LF & HT & "movl %%ebx, %1", Outputs => Unsigned_32'Asm_Output ("=g", Var_Out), Inputs => Unsigned_32'Asm_Input ("g", Var_In), Clobber => "ebx", Volatile => True); -@end group -@end smallexample +@end example +@end quotation -By default, @code{Volatile} is set to @code{False} unless there is no -@code{Outputs} parameter. +By default, @cite{Volatile} is set to @cite{False} unless there is no +@cite{Outputs} parameter. -Although setting @code{Volatile} to @code{True} prevents unwanted +Although setting @cite{Volatile} to @cite{True} prevents unwanted optimizations, it will also disable other optimizations that might be -important for efficiency. In general, you should set @code{Volatile} -to @code{True} only if the compiler's optimizations have created +important for efficiency. In general, you should set @cite{Volatile} +to @cite{True} only if the compiler's optimizations have created problems. -@c END OF INLINE ASSEMBLER CHAPTER -@c =============================== - - -@c ***************************************** -@c Writing Portable Fixed-Point Declarations -@c ***************************************** -@node Writing Portable Fixed-Point Declarations -@appendix Writing Portable Fixed-Point Declarations -@cindex Fixed-point types (writing portable declarations) - -@noindent -The Ada Reference Manual gives an implementation freedom to choose bounds -that are narrower by @code{Small} from the given bounds. -For example, if we write - -@smallexample @c ada - type F1 is delta 1.0 range -128.0 .. +128.0; -@end smallexample - -@noindent -then the implementation is allowed to choose -128.0 .. +127.0 if it -likes, but is not required to do so. - -This leads to possible portability problems, so let's have a closer -look at this, and figure out how to avoid these problems. - -First, why does this freedom exist, and why would an implementation -take advantage of it? To answer this, take a closer look at the type -declaration for @code{F1} above. If the compiler uses the given bounds, -it would need 9 bits to hold the largest positive value (and typically -that means 16 bits on all machines). But if the implementation chooses -the +127.0 bound then it can fit values of the type in 8 bits. - -Why not make the user write +127.0 if that's what is wanted? -The rationale is that if you are thinking of fixed point -as a kind of ``poor man's floating-point'', then you don't want -to be thinking about the scaled integers that are used in its -representation. Let's take another example: - -@smallexample @c ada - type F2 is delta 2.0**(-15) range -1.0 .. +1.0; -@end smallexample - -@noindent -Looking at this declaration, it seems casually as though -it should fit in 16 bits, but again that extra positive value -+1.0 has the scaled integer equivalent of 2**15 which is one too -big for signed 16 bits. The implementation can treat this as: - -@smallexample @c ada - type F2 is delta 2.0**(-15) range -1.0 .. +1.0-(2.0**(-15)); -@end smallexample - -@noindent -and the Ada language design team felt that this was too annoying -to require. We don't need to debate this decision at this point, -since it is well established (the rule about narrowing the ranges -dates to Ada 83). - -But the important point is that an implementation is not required -to do this narrowing, so we have a potential portability problem. -We could imagine three types of implementation: - -@enumerate a -@item -those that narrow the range automatically if they can figure -out that the narrower range will allow storage in a smaller machine unit, - -@item -those that will narrow only if forced to by a @code{'Size} clause, and - -@item -those that will never narrow. -@end enumerate - -@noindent -Now if we are language theoreticians, we can imagine a fourth -approach: is to narrow all the time, e.g. to treat - -@smallexample @c ada - type F3 is delta 1.0 range -10.0 .. +23.0; -@end smallexample - -@noindent -as though it had been written: - -@smallexample @c ada - type F3 is delta 1.0 range -9.0 .. +22.0; -@end smallexample - -@noindent -But although technically allowed, such a behavior would be hostile and silly, -and no real compiler would do this. All real compilers will fall into one of -the categories (a), (b) or (c) above. - -So, how do you get the compiler to do what you want? The answer is give the -actual bounds you want, and then use a @code{'Small} clause and a -@code{'Size} clause to absolutely pin down what the compiler does. -E.g., for @code{F2} above, we will write: - -@smallexample @c ada -@group - My_Small : constant := 2.0**(-15); - My_First : constant := -1.0; - My_Last : constant := +1.0 - My_Small; - - type F2 is delta My_Small range My_First .. My_Last; -@end group -@end smallexample - -@noindent -and then add - -@smallexample @c ada -@group - for F2'Small use my_Small; - for F2'Size use 16; -@end group -@end smallexample - -@noindent -In practice all compilers will do the same thing here and will give you -what you want, so the above declarations are fully portable. If you really -want to play language lawyer and guard against ludicrous behavior by the -compiler you could add - -@smallexample @c ada -@group - Test1 : constant := 1 / Boolean'Pos (F2'First = My_First); - Test2 : constant := 1 / Boolean'Pos (F2'Last = My_Last); -@end group -@end smallexample - -@noindent -One or other or both are allowed to be illegal if the compiler is -behaving in a silly manner, but at least the silly compiler will not -get away with silently messing with your (very clear) intentions. - -If you follow this scheme you will be guaranteed that your fixed-point -types will be portable. - - -@c *********************************** -@c * Compatibility and Porting Guide * -@c *********************************** -@node Compatibility and Porting Guide -@appendix Compatibility and Porting Guide - -@noindent -This chapter describes the compatibility issues that may arise between -GNAT and other Ada compilation systems (including those for Ada 83), -and shows how GNAT can expedite porting -applications developed in other Ada environments. - -@menu -* Compatibility with Ada 83:: -* Compatibility between Ada 95 and Ada 2005:: -* Implementation-dependent characteristics:: -* Compatibility with Other Ada Systems:: -* Representation Clauses:: -@c Brief section is only in non-VMS version -@c Full chapter is in VMS version -* Compatibility with HP Ada 83:: -@end menu - -@node Compatibility with Ada 83 -@section Compatibility with Ada 83 -@cindex Compatibility (between Ada 83 and Ada 95 / Ada 2005) - -@noindent -Ada 95 and Ada 2005 are highly upwards compatible with Ada 83. In -particular, the design intention was that the difficulties associated -with moving from Ada 83 to Ada 95 or Ada 2005 should be no greater than those -that occur when moving from one Ada 83 system to another. - -However, there are a number of points at which there are minor -incompatibilities. The @cite{Ada 95 Annotated Reference Manual} contains -full details of these issues, -and should be consulted for a complete treatment. -In practice the -following subsections treat the most likely issues to be encountered. - -@menu -* Legal Ada 83 programs that are illegal in Ada 95:: -* More deterministic semantics:: -* Changed semantics:: -* Other language compatibility issues:: -@end menu - -@node Legal Ada 83 programs that are illegal in Ada 95 -@subsection Legal Ada 83 programs that are illegal in Ada 95 - -Some legal Ada 83 programs are illegal (i.e., they will fail to compile) in -Ada 95 and thus also in Ada 2005: - -@table @emph -@item Character literals -Some uses of character literals are ambiguous. Since Ada 95 has introduced -@code{Wide_Character} as a new predefined character type, some uses of -character literals that were legal in Ada 83 are illegal in Ada 95. -For example: -@smallexample @c ada - @b{for} Char @b{in} 'A' .. 'Z' @b{loop} @dots{} @b{end} @b{loop}; -@end smallexample - -@noindent -The problem is that @code{'A'} and @code{'Z'} could be from either -@code{Character} or @code{Wide_Character}. The simplest correction -is to make the type explicit; e.g.: -@smallexample @c ada - @b{for} Char @b{in} Character @b{range} 'A' .. 'Z' @b{loop} @dots{} @b{end} @b{loop}; -@end smallexample - -@item New reserved words -The identifiers @code{abstract}, @code{aliased}, @code{protected}, -@code{requeue}, @code{tagged}, and @code{until} are reserved in Ada 95. -Existing Ada 83 code using any of these identifiers must be edited to -use some alternative name. - -@item Freezing rules -The rules in Ada 95 are slightly different with regard to the point at -which entities are frozen, and representation pragmas and clauses are -not permitted past the freeze point. This shows up most typically in -the form of an error message complaining that a representation item -appears too late, and the appropriate corrective action is to move -the item nearer to the declaration of the entity to which it refers. - -A particular case is that representation pragmas -cannot be applied to a subprogram body. If necessary, a separate subprogram -declaration must be introduced to which the pragma can be applied. - -@item Optional bodies for library packages -In Ada 83, a package that did not require a package body was nevertheless -allowed to have one. This lead to certain surprises in compiling large -systems (situations in which the body could be unexpectedly ignored by the -binder). In Ada 95, if a package does not require a body then it is not -permitted to have a body. To fix this problem, simply remove a redundant -body if it is empty, or, if it is non-empty, introduce a dummy declaration -into the spec that makes the body required. One approach is to add a private -part to the package declaration (if necessary), and define a parameterless -procedure called @code{Requires_Body}, which must then be given a dummy -procedure body in the package body, which then becomes required. -Another approach (assuming that this does not introduce elaboration -circularities) is to add an @code{Elaborate_Body} pragma to the package spec, -since one effect of this pragma is to require the presence of a package body. - -@item @code{Numeric_Error} is now the same as @code{Constraint_Error} -In Ada 95, the exception @code{Numeric_Error} is a renaming of -@code{Constraint_Error}. -This means that it is illegal to have separate exception handlers for -the two exceptions. The fix is simply to remove the handler for the -@code{Numeric_Error} case (since even in Ada 83, a compiler was free to raise -@code{Constraint_Error} in place of @code{Numeric_Error} in all cases). - -@item Indefinite subtypes in generics -In Ada 83, it was permissible to pass an indefinite type (e.g.@: @code{String}) -as the actual for a generic formal private type, but then the instantiation -would be illegal if there were any instances of declarations of variables -of this type in the generic body. In Ada 95, to avoid this clear violation -of the methodological principle known as the ``contract model'', -the generic declaration explicitly indicates whether -or not such instantiations are permitted. If a generic formal parameter -has explicit unknown discriminants, indicated by using @code{(<>)} after the -subtype name, then it can be instantiated with indefinite types, but no -stand-alone variables can be declared of this type. Any attempt to declare -such a variable will result in an illegality at the time the generic is -declared. If the @code{(<>)} notation is not used, then it is illegal -to instantiate the generic with an indefinite type. -This is the potential incompatibility issue when porting Ada 83 code to Ada 95. -It will show up as a compile time error, and -the fix is usually simply to add the @code{(<>)} to the generic declaration. -@end table - -@node More deterministic semantics -@subsection More deterministic semantics - -@table @emph -@item Conversions -Conversions from real types to integer types round away from 0. In Ada 83 -the conversion Integer(2.5) could deliver either 2 or 3 as its value. This -implementation freedom was intended to support unbiased rounding in -statistical applications, but in practice it interfered with portability. -In Ada 95 the conversion semantics are unambiguous, and rounding away from 0 -is required. Numeric code may be affected by this change in semantics. -Note, though, that this issue is no worse than already existed in Ada 83 -when porting code from one vendor to another. - -@item Tasking -The Real-Time Annex introduces a set of policies that define the behavior of -features that were implementation dependent in Ada 83, such as the order in -which open select branches are executed. -@end table - -@node Changed semantics -@subsection Changed semantics - -@noindent -The worst kind of incompatibility is one where a program that is legal in -Ada 83 is also legal in Ada 95 but can have an effect in Ada 95 that was not -possible in Ada 83. Fortunately this is extremely rare, but the one -situation that you should be alert to is the change in the predefined type -@code{Character} from 7-bit ASCII to 8-bit Latin-1. - -@table @emph -@item Range of type @code{Character} -The range of @code{Standard.Character} is now the full 256 characters -of Latin-1, whereas in most Ada 83 implementations it was restricted -to 128 characters. Although some of the effects of -this change will be manifest in compile-time rejection of legal -Ada 83 programs it is possible for a working Ada 83 program to have -a different effect in Ada 95, one that was not permitted in Ada 83. -As an example, the expression -@code{Character'Pos(Character'Last)} returned @code{127} in Ada 83 and now -delivers @code{255} as its value. -In general, you should look at the logic of any -character-processing Ada 83 program and see whether it needs to be adapted -to work correctly with Latin-1. Note that the predefined Ada 95 API has a -character handling package that may be relevant if code needs to be adapted -to account for the additional Latin-1 elements. -The desirable fix is to -modify the program to accommodate the full character set, but in some cases -it may be convenient to define a subtype or derived type of Character that -covers only the restricted range. -@cindex Latin-1 -@end table - -@node Other language compatibility issues -@subsection Other language compatibility issues - -@table @emph -@item @option{-gnat83} switch -All implementations of GNAT provide a switch that causes GNAT to operate -in Ada 83 mode. In this mode, some but not all compatibility problems -of the type described above are handled automatically. For example, the -new reserved words introduced in Ada 95 and Ada 2005 are treated simply -as identifiers as in Ada 83. -However, -in practice, it is usually advisable to make the necessary modifications -to the program to remove the need for using this switch. -See @ref{Compiling Different Versions of Ada}. - -@item Support for removed Ada 83 pragmas and attributes -A number of pragmas and attributes from Ada 83 were removed from Ada 95, -generally because they were replaced by other mechanisms. Ada 95 and Ada 2005 -compilers are allowed, but not required, to implement these missing -elements. In contrast with some other compilers, GNAT implements all -such pragmas and attributes, eliminating this compatibility concern. These -include @code{pragma Interface} and the floating point type attributes -(@code{Emax}, @code{Mantissa}, etc.), among other items. -@end table - - -@node Compatibility between Ada 95 and Ada 2005 -@section Compatibility between Ada 95 and Ada 2005 -@cindex Compatibility between Ada 95 and Ada 2005 - -@noindent -Although Ada 2005 was designed to be upwards compatible with Ada 95, there are -a number of incompatibilities. Several are enumerated below; -for a complete description please see the -Annotated Ada 2005 Reference Manual, or section 9.1.1 in -@cite{Rationale for Ada 2005}. - -@table @emph -@item New reserved words. -The words @code{interface}, @code{overriding} and @code{synchronized} are -reserved in Ada 2005. -A pre-Ada 2005 program that uses any of these as an identifier will be -illegal. - -@item New declarations in predefined packages. -A number of packages in the predefined environment contain new declarations: -@code{Ada.Exceptions}, @code{Ada.Real_Time}, @code{Ada.Strings}, -@code{Ada.Strings.Fixed}, @code{Ada.Strings.Bounded}, -@code{Ada.Strings.Unbounded}, @code{Ada.Strings.Wide_Fixed}, -@code{Ada.Strings.Wide_Bounded}, @code{Ada.Strings.Wide_Unbounded}, -@code{Ada.Tags}, @code{Ada.Text_IO}, and @code{Interfaces.C}. -If an Ada 95 program does a @code{with} and @code{use} of any of these -packages, the new declarations may cause name clashes. - -@item Access parameters. -A nondispatching subprogram with an access parameter cannot be renamed -as a dispatching operation. This was permitted in Ada 95. - -@item Access types, discriminants, and constraints. -Rule changes in this area have led to some incompatibilities; for example, -constrained subtypes of some access types are not permitted in Ada 2005. - -@item Aggregates for limited types. -The allowance of aggregates for limited types in Ada 2005 raises the -possibility of ambiguities in legal Ada 95 programs, since additional types -now need to be considered in expression resolution. - -@item Fixed-point multiplication and division. -Certain expressions involving ``*'' or ``/'' for a fixed-point type, which -were legal in Ada 95 and invoked the predefined versions of these operations, -are now ambiguous. -The ambiguity may be resolved either by applying a type conversion to the -expression, or by explicitly invoking the operation from package -@code{Standard}. - -@item Return-by-reference types. -The Ada 95 return-by-reference mechanism has been removed. Instead, the user -can declare a function returning a value from an anonymous access type. -@end table - - -@node Implementation-dependent characteristics -@section Implementation-dependent characteristics -@noindent -Although the Ada language defines the semantics of each construct as -precisely as practical, in some situations (for example for reasons of -efficiency, or where the effect is heavily dependent on the host or target -platform) the implementation is allowed some freedom. In porting Ada 83 -code to GNAT, you need to be aware of whether / how the existing code -exercised such implementation dependencies. Such characteristics fall into -several categories, and GNAT offers specific support in assisting the -transition from certain Ada 83 compilers. - -@menu -* Implementation-defined pragmas:: -* Implementation-defined attributes:: -* Libraries:: -* Elaboration order:: -* Target-specific aspects:: -@end menu - -@node Implementation-defined pragmas -@subsection Implementation-defined pragmas - -@noindent -Ada compilers are allowed to supplement the language-defined pragmas, and -these are a potential source of non-portability. All GNAT-defined pragmas -are described in @ref{Implementation Defined Pragmas,,, gnat_rm, GNAT -Reference Manual}, and these include several that are specifically -intended to correspond to other vendors' Ada 83 pragmas. -For migrating from VADS, the pragma @code{Use_VADS_Size} may be useful. -For compatibility with HP Ada 83, GNAT supplies the pragmas -@code{Extend_System}, @code{Ident}, @code{Inline_Generic}, -@code{Interface_Name}, @code{Passive}, @code{Suppress_All}, -and @code{Volatile}. -Other relevant pragmas include @code{External} and @code{Link_With}. -Some vendor-specific -Ada 83 pragmas (@code{Share_Generic}, @code{Subtitle}, and @code{Title}) are -recognized, thus -avoiding compiler rejection of units that contain such pragmas; they are not -relevant in a GNAT context and hence are not otherwise implemented. - -@node Implementation-defined attributes -@subsection Implementation-defined attributes - -Analogous to pragmas, the set of attributes may be extended by an -implementation. All GNAT-defined attributes are described in -@ref{Implementation Defined Attributes,,, gnat_rm, GNAT Reference -Manual}, and these include several that are specifically intended -to correspond to other vendors' Ada 83 attributes. For migrating from VADS, -the attribute @code{VADS_Size} may be useful. For compatibility with HP -Ada 83, GNAT supplies the attributes @code{Bit}, @code{Machine_Size} and -@code{Type_Class}. - -@node Libraries -@subsection Libraries -@noindent -Vendors may supply libraries to supplement the standard Ada API. If Ada 83 -code uses vendor-specific libraries then there are several ways to manage -this in Ada 95 or Ada 2005: -@enumerate -@item -If the source code for the libraries (specs and bodies) are -available, then the libraries can be migrated in the same way as the -application. -@item -If the source code for the specs but not the bodies are -available, then you can reimplement the bodies. -@item -Some features introduced by Ada 95 obviate the need for library support. For -example most Ada 83 vendors supplied a package for unsigned integers. The -Ada 95 modular type feature is the preferred way to handle this need, so -instead of migrating or reimplementing the unsigned integer package it may -be preferable to retrofit the application using modular types. -@end enumerate - -@node Elaboration order -@subsection Elaboration order -@noindent -The implementation can choose any elaboration order consistent with the unit -dependency relationship. This freedom means that some orders can result in -Program_Error being raised due to an ``Access Before Elaboration'': an attempt -to invoke a subprogram its body has been elaborated, or to instantiate a -generic before the generic body has been elaborated. By default GNAT -attempts to choose a safe order (one that will not encounter access before -elaboration problems) by implicitly inserting @code{Elaborate} or -@code{Elaborate_All} pragmas where -needed. However, this can lead to the creation of elaboration circularities -and a resulting rejection of the program by gnatbind. This issue is -thoroughly described in @ref{Elaboration Order Handling in GNAT}. -In brief, there are several -ways to deal with this situation: - -@itemize @bullet -@item -Modify the program to eliminate the circularities, e.g.@: by moving -elaboration-time code into explicitly-invoked procedures -@item -Constrain the elaboration order by including explicit @code{Elaborate_Body} or -@code{Elaborate} pragmas, and then inhibit the generation of implicit -@code{Elaborate_All} -pragmas either globally (as an effect of the @option{-gnatE} switch) or locally -(by selectively suppressing elaboration checks via pragma -@code{Suppress(Elaboration_Check)} when it is safe to do so). -@end itemize - -@node Target-specific aspects -@subsection Target-specific aspects -@noindent -Low-level applications need to deal with machine addresses, data -representations, interfacing with assembler code, and similar issues. If -such an Ada 83 application is being ported to different target hardware (for -example where the byte endianness has changed) then you will need to -carefully examine the program logic; the porting effort will heavily depend -on the robustness of the original design. Moreover, Ada 95 (and thus -Ada 2005) are sometimes -incompatible with typical Ada 83 compiler practices regarding implicit -packing, the meaning of the Size attribute, and the size of access values. -GNAT's approach to these issues is described in @ref{Representation Clauses}. - -@node Compatibility with Other Ada Systems -@section Compatibility with Other Ada Systems - -@noindent -If programs avoid the use of implementation dependent and -implementation defined features, as documented in the @cite{Ada -Reference Manual}, there should be a high degree of portability between -GNAT and other Ada systems. The following are specific items which -have proved troublesome in moving Ada 95 programs from GNAT to other Ada 95 -compilers, but do not affect porting code to GNAT@. -(As of @value{NOW}, GNAT is the only compiler available for Ada 2005; -the following issues may or may not arise for Ada 2005 programs -when other compilers appear.) - -@table @emph -@item Ada 83 Pragmas and Attributes -Ada 95 compilers are allowed, but not required, to implement the missing -Ada 83 pragmas and attributes that are no longer defined in Ada 95. -GNAT implements all such pragmas and attributes, eliminating this as -a compatibility concern, but some other Ada 95 compilers reject these -pragmas and attributes. - -@item Specialized Needs Annexes -GNAT implements the full set of special needs annexes. At the -current time, it is the only Ada 95 compiler to do so. This means that -programs making use of these features may not be portable to other Ada -95 compilation systems. - -@item Representation Clauses -Some other Ada 95 compilers implement only the minimal set of -representation clauses required by the Ada 95 reference manual. GNAT goes -far beyond this minimal set, as described in the next section. -@end table - -@node Representation Clauses -@section Representation Clauses - -@noindent -The Ada 83 reference manual was quite vague in describing both the minimal -required implementation of representation clauses, and also their precise -effects. Ada 95 (and thus also Ada 2005) are much more explicit, but the -minimal set of capabilities required is still quite limited. - -GNAT implements the full required set of capabilities in -Ada 95 and Ada 2005, but also goes much further, and in particular -an effort has been made to be compatible with existing Ada 83 usage to the -greatest extent possible. - -A few cases exist in which Ada 83 compiler behavior is incompatible with -the requirements in Ada 95 (and thus also Ada 2005). These are instances of -intentional or accidental dependence on specific implementation dependent -characteristics of these Ada 83 compilers. The following is a list of -the cases most likely to arise in existing Ada 83 code. - -@table @emph -@item Implicit Packing -Some Ada 83 compilers allowed a Size specification to cause implicit -packing of an array or record. This could cause expensive implicit -conversions for change of representation in the presence of derived -types, and the Ada design intends to avoid this possibility. -Subsequent AI's were issued to make it clear that such implicit -change of representation in response to a Size clause is inadvisable, -and this recommendation is represented explicitly in the Ada 95 (and Ada 2005) -Reference Manuals as implementation advice that is followed by GNAT@. -The problem will show up as an error -message rejecting the size clause. The fix is simply to provide -the explicit pragma @code{Pack}, or for more fine tuned control, provide -a Component_Size clause. - -@item Meaning of Size Attribute -The Size attribute in Ada 95 (and Ada 2005) for discrete types is defined as -the minimal number of bits required to hold values of the type. For example, -on a 32-bit machine, the size of @code{Natural} will typically be 31 and not -32 (since no sign bit is required). Some Ada 83 compilers gave 31, and -some 32 in this situation. This problem will usually show up as a compile -time error, but not always. It is a good idea to check all uses of the -'Size attribute when porting Ada 83 code. The GNAT specific attribute -Object_Size can provide a useful way of duplicating the behavior of -some Ada 83 compiler systems. - -@item Size of Access Types -A common assumption in Ada 83 code is that an access type is in fact a pointer, -and that therefore it will be the same size as a System.Address value. This -assumption is true for GNAT in most cases with one exception. For the case of -a pointer to an unconstrained array type (where the bounds may vary from one -value of the access type to another), the default is to use a ``fat pointer'', -which is represented as two separate pointers, one to the bounds, and one to -the array. This representation has a number of advantages, including improved -efficiency. However, it may cause some difficulties in porting existing Ada 83 -code which makes the assumption that, for example, pointers fit in 32 bits on -a machine with 32-bit addressing. - -To get around this problem, GNAT also permits the use of ``thin pointers'' for -access types in this case (where the designated type is an unconstrained array -type). These thin pointers are indeed the same size as a System.Address value. -To specify a thin pointer, use a size clause for the type, for example: - -@smallexample @c ada -@b{type} X @b{is} @b{access} @b{all} String; -@b{for} X'Size @b{use} Standard'Address_Size; -@end smallexample - -@noindent -which will cause the type X to be represented using a single pointer. -When using this representation, the bounds are right behind the array. -This representation is slightly less efficient, and does not allow quite -such flexibility in the use of foreign pointers or in using the -Unrestricted_Access attribute to create pointers to non-aliased objects. -But for any standard portable use of the access type it will work in -a functionally correct manner and allow porting of existing code. -Note that another way of forcing a thin pointer representation -is to use a component size clause for the element size in an array, -or a record representation clause for an access field in a record. - -See the documentation of Unrestricted_Access in the GNAT RM for a -full discussion of possible problems using this attribute in conjunction -with thin pointers. -@end table - -@c This brief section is only in the non-VMS version -@c The complete chapter on HP Ada is in the VMS version -@node Compatibility with HP Ada 83 -@section Compatibility with HP Ada 83 - -@noindent -The VMS version of GNAT fully implements all the pragmas and attributes -provided by HP Ada 83, as well as providing the standard HP Ada 83 -libraries, including Starlet. In addition, data layouts and parameter -passing conventions are highly compatible. This means that porting -existing HP Ada 83 code to GNAT in VMS systems should be easier than -most other porting efforts. The following are some of the most -significant differences between GNAT and HP Ada 83. - -@table @emph -@item Default floating-point representation -In GNAT, the default floating-point format is IEEE, whereas in HP Ada 83, -it is VMS format. GNAT does implement the necessary pragmas -(Long_Float, Float_Representation) for changing this default. - -@item System -The package System in GNAT exactly corresponds to the definition in the -Ada 95 reference manual, which means that it excludes many of the -HP Ada 83 extensions. However, a separate package Aux_DEC is provided -that contains the additional definitions, and a special pragma, -Extend_System allows this package to be treated transparently as an -extension of package System. - -@item To_Address -The definitions provided by Aux_DEC are exactly compatible with those -in the HP Ada 83 version of System, with one exception. -HP Ada provides the following declarations: - -@smallexample @c ada -TO_ADDRESS (INTEGER) -TO_ADDRESS (UNSIGNED_LONGWORD) -TO_ADDRESS (@i{universal_integer}) -@end smallexample - -@noindent -The version of TO_ADDRESS taking a @i{universal integer} argument is in fact -an extension to Ada 83 not strictly compatible with the reference manual. -In GNAT, we are constrained to be exactly compatible with the standard, -and this means we cannot provide this capability. In HP Ada 83, the -point of this definition is to deal with a call like: - -@smallexample @c ada -TO_ADDRESS (16#12777#); -@end smallexample - -@noindent -Normally, according to the Ada 83 standard, one would expect this to be -ambiguous, since it matches both the INTEGER and UNSIGNED_LONGWORD forms -of TO_ADDRESS@. However, in HP Ada 83, there is no ambiguity, since the -definition using @i{universal_integer} takes precedence. - -In GNAT, since the version with @i{universal_integer} cannot be supplied, it -is not possible to be 100% compatible. Since there are many programs using -numeric constants for the argument to TO_ADDRESS, the decision in GNAT was -to change the name of the function in the UNSIGNED_LONGWORD case, so the -declarations provided in the GNAT version of AUX_Dec are: - -@smallexample @c ada -@b{function} To_Address (X : Integer) @b{return} Address; -@b{pragma} Pure_Function (To_Address); - -@b{function} To_Address_Long (X : Unsigned_Longword) - @b{return} Address; -@b{pragma} Pure_Function (To_Address_Long); -@end smallexample - -@noindent -This means that programs using TO_ADDRESS for UNSIGNED_LONGWORD must -change the name to TO_ADDRESS_LONG@. - -@item Task_Id values -The Task_Id values assigned will be different in the two systems, and GNAT -does not provide a specified value for the Task_Id of the environment task, -which in GNAT is treated like any other declared task. -@end table - -@noindent -For full details on these and other less significant compatibility issues, -see appendix E of the HP publication entitled @cite{HP Ada, Technical -Overview and Comparison on HP Platforms}. - -For GNAT running on other than VMS systems, all the HP Ada 83 pragmas and -attributes are recognized, although only a subset of them can sensibly -be implemented. The description of pragmas in @ref{Implementation -Defined Pragmas,,, gnat_rm, GNAT Reference Manual} -indicates whether or not they are applicable to non-VMS systems. - - -@c ************************************************ -@node Microsoft Windows Topics -@appendix Microsoft Windows Topics -@cindex Windows NT -@cindex Windows 95 -@cindex Windows 98 - -@noindent -This chapter describes topics that are specific to the Microsoft Windows -platforms (NT, 2000, and XP Professional). - -@menu -@ifclear FSFEDITION -* Installing from the Command Line:: -@end ifclear -* Using GNAT on Windows:: -* Using a network installation of GNAT:: -* CONSOLE and WINDOWS subsystems:: -* Temporary Files:: -* Mixed-Language Programming on Windows:: -* Windows Calling Conventions:: -* Introduction to Dynamic Link Libraries (DLLs):: -* Using DLLs with GNAT:: -* Building DLLs with GNAT Project files:: -* Building DLLs with GNAT:: -* Building DLLs with gnatdll:: -* GNAT and Windows Resources:: -* Debugging a DLL:: -* Setting Stack Size from gnatlink:: -* Setting Heap Size from gnatlink:: -@end menu - -@ifclear FSFEDITION -@node Installing from the Command Line -@section Installing from the Command Line -@cindex Batch installation -@cindex Silent installation -@cindex Unassisted installation - -@noindent -By default the @value{EDITION} installers display a GUI that prompts the user -to enter installation path and similar information, and guide him through the -installation process. It is also possible to perform silent installations -using the command-line interface. - -In order to install one of the @value{EDITION} installers from the command -line you should pass parameter @code{/S} (and, optionally, -@code{/D=<directory>}) as command-line arguments. - -@ifset PROEDITION -For example, for an unattended installation of -@value{EDITION} 7.0.2 into the default directory -@code{C:\GNATPRO\7.0.2} you would run: - -@smallexample -gnatpro-7.0.2-i686-pc-mingw32-bin.exe /S -@end smallexample - -To install into a custom directory, say, @code{C:\TOOLS\GNATPRO\7.0.2}: - -@smallexample -gnatpro-7.0.2-i686-pc-mingw32-bin /S /D=C:\TOOLS\GNATPRO\7.0.2 -@end smallexample -@end ifset - -@ifset GPLEDITION -For example, for an unattended installation of -@value{EDITION} 2012 into @code{C:\GNAT\2012}: - -@smallexample -gnat-gpl-2012-i686-pc-mingw32-bin /S /D=C:\GNAT\2012 -@end smallexample -@end ifset - -You can use the same syntax for all installers. - -Note that unattended installations don't modify system path, nor create file -associations, so such activities need to be done by hand. -@end ifclear - -@node Using GNAT on Windows -@section Using GNAT on Windows - -@noindent -One of the strengths of the GNAT technology is that its tool set -(@command{gcc}, @command{gnatbind}, @command{gnatlink}, @command{gnatmake}, the -@code{gdb} debugger, etc.) is used in the same way regardless of the -platform. - -On Windows this tool set is complemented by a number of Microsoft-specific -tools that have been provided to facilitate interoperability with Windows -when this is required. With these tools: - -@itemize @bullet - -@item -You can build applications using the @code{CONSOLE} or @code{WINDOWS} -subsystems. - -@item -You can use any Dynamically Linked Library (DLL) in your Ada code (both -relocatable and non-relocatable DLLs are supported). - -@item -You can build Ada DLLs for use in other applications. These applications -can be written in a language other than Ada (e.g., C, C++, etc). Again both -relocatable and non-relocatable Ada DLLs are supported. - -@item -You can include Windows resources in your Ada application. - -@item -You can use or create COM/DCOM objects. -@end itemize - -@noindent -Immediately below are listed all known general GNAT-for-Windows restrictions. -Other restrictions about specific features like Windows Resources and DLLs -are listed in separate sections below. - -@itemize @bullet - -@item -It is not possible to use @code{GetLastError} and @code{SetLastError} -when tasking, protected records, or exceptions are used. In these -cases, in order to implement Ada semantics, the GNAT run-time system -calls certain Win32 routines that set the last error variable to 0 upon -success. It should be possible to use @code{GetLastError} and -@code{SetLastError} when tasking, protected record, and exception -features are not used, but it is not guaranteed to work. - -@item -It is not possible to link against Microsoft C++ libraries except for -import libraries. Interfacing must be done by the mean of DLLs. - -@item -It is possible to link against Microsoft C libraries. Yet the preferred -solution is to use C/C++ compiler that comes with @value{EDITION}, since it -doesn't require having two different development environments and makes the -inter-language debugging experience smoother. - -@item -When the compilation environment is located on FAT32 drives, users may -experience recompilations of the source files that have not changed if -Daylight Saving Time (DST) state has changed since the last time files -were compiled. NTFS drives do not have this problem. - -@item -No components of the GNAT toolset use any entries in the Windows -registry. The only entries that can be created are file associations and -PATH settings, provided the user has chosen to create them at installation -time, as well as some minimal book-keeping information needed to correctly -uninstall or integrate different GNAT products. -@end itemize - -@node Using a network installation of GNAT -@section Using a network installation of GNAT - -@noindent -Make sure the system on which GNAT is installed is accessible from the -current machine, i.e., the install location is shared over the network. -Shared resources are accessed on Windows by means of UNC paths, which -have the format @code{\\server\sharename\path} - -In order to use such a network installation, simply add the UNC path of the -@file{bin} directory of your GNAT installation in front of your PATH. For -example, if GNAT is installed in @file{\GNAT} directory of a share location -called @file{c-drive} on a machine @file{LOKI}, the following command will -make it available: - -@code{@ @ @ path \\loki\c-drive\gnat\bin;%path%} - -Be aware that every compilation using the network installation results in the -transfer of large amounts of data across the network and will likely cause -serious performance penalty. - -@node CONSOLE and WINDOWS subsystems -@section CONSOLE and WINDOWS subsystems -@cindex CONSOLE Subsystem -@cindex WINDOWS Subsystem -@cindex -mwindows - -@noindent -There are two main subsystems under Windows. The @code{CONSOLE} subsystem -(which is the default subsystem) will always create a console when -launching the application. This is not something desirable when the -application has a Windows GUI. To get rid of this console the -application must be using the @code{WINDOWS} subsystem. To do so -the @option{-mwindows} linker option must be specified. - -@smallexample -$ gnatmake winprog -largs -mwindows -@end smallexample - -@node Temporary Files -@section Temporary Files -@cindex Temporary files - -@noindent -It is possible to control where temporary files gets created by setting -the @env{TMP} environment variable. The file will be created: - -@itemize -@item Under the directory pointed to by the @env{TMP} environment variable if -this directory exists. - -@item Under @file{c:\temp}, if the @env{TMP} environment variable is not -set (or not pointing to a directory) and if this directory exists. - -@item Under the current working directory otherwise. -@end itemize - -@noindent -This allows you to determine exactly where the temporary -file will be created. This is particularly useful in networked -environments where you may not have write access to some -directories. - -@node Mixed-Language Programming on Windows -@section Mixed-Language Programming on Windows - -@noindent -Developing pure Ada applications on Windows is no different than on -other GNAT-supported platforms. However, when developing or porting an -application that contains a mix of Ada and C/C++, the choice of your -Windows C/C++ development environment conditions your overall -interoperability strategy. - -If you use @command{gcc} or Microsoft C to compile the non-Ada part of -your application, there are no Windows-specific restrictions that -affect the overall interoperability with your Ada code. If you do want -to use the Microsoft tools for your C++ code, you have two choices: - -@enumerate -@item -Encapsulate your C++ code in a DLL to be linked with your Ada -application. In this case, use the Microsoft or whatever environment to -build the DLL and use GNAT to build your executable -(@pxref{Using DLLs with GNAT}). - -@item -Or you can encapsulate your Ada code in a DLL to be linked with the -other part of your application. In this case, use GNAT to build the DLL -(@pxref{Building DLLs with GNAT Project files}) and use the Microsoft -or whatever environment to build your executable. -@end enumerate - -In addition to the description about C main in -@pxref{Mixed Language Programming} section, if the C main uses a -stand-alone library it is required on x86-windows to -setup the SEH context. For this the C main must looks like this: - -@smallexample -/* main.c */ -extern void adainit (void); -extern void adafinal (void); -extern void __gnat_initialize(void*); -extern void call_to_ada (void); - -int main (int argc, char *argv[]) -@{ - int SEH [2]; - - /* Initialize the SEH context */ - __gnat_initialize (&SEH); - - adainit(); - - /* Then call Ada services in the stand-alone library */ - - call_to_ada(); - - adafinal(); -@} -@end smallexample - -Note that this is not needed on x86_64-windows where the Windows -native SEH support is used. - -@node Windows Calling Conventions -@section Windows Calling Conventions -@findex Stdcall -@findex APIENTRY - -This section pertain only to Win32. On Win64 there is a single native -calling convention. All convention specifiers are ignored on this -platform. - -@menu -* C Calling Convention:: -* Stdcall Calling Convention:: -* Win32 Calling Convention:: -* DLL Calling Convention:: -@end menu - -@noindent -When a subprogram @code{F} (caller) calls a subprogram @code{G} -(callee), there are several ways to push @code{G}'s parameters on the -stack and there are several possible scenarios to clean up the stack -upon @code{G}'s return. A calling convention is an agreed upon software -protocol whereby the responsibilities between the caller (@code{F}) and -the callee (@code{G}) are clearly defined. Several calling conventions -are available for Windows: - -@itemize @bullet -@item -@code{C} (Microsoft defined) - -@item -@code{Stdcall} (Microsoft defined) - -@item -@code{Win32} (GNAT specific) - -@item -@code{DLL} (GNAT specific) -@end itemize - -@node C Calling Convention -@subsection @code{C} Calling Convention - -@noindent -This is the default calling convention used when interfacing to C/C++ -routines compiled with either @command{gcc} or Microsoft Visual C++. - -In the @code{C} calling convention subprogram parameters are pushed on the -stack by the caller from right to left. The caller itself is in charge of -cleaning up the stack after the call. In addition, the name of a routine -with @code{C} calling convention is mangled by adding a leading underscore. - -The name to use on the Ada side when importing (or exporting) a routine -with @code{C} calling convention is the name of the routine. For -instance the C function: - -@smallexample -int get_val (long); -@end smallexample - -@noindent -should be imported from Ada as follows: - -@smallexample @c ada -@group -@b{function} Get_Val (V : Interfaces.C.long) @b{return} Interfaces.C.int; -@b{pragma} Import (C, Get_Val, External_Name => "get_val"); -@end group -@end smallexample - -@noindent -Note that in this particular case the @code{External_Name} parameter could -have been omitted since, when missing, this parameter is taken to be the -name of the Ada entity in lower case. When the @code{Link_Name} parameter -is missing, as in the above example, this parameter is set to be the -@code{External_Name} with a leading underscore. - -When importing a variable defined in C, you should always use the @code{C} -calling convention unless the object containing the variable is part of a -DLL (in which case you should use the @code{Stdcall} calling -convention, @pxref{Stdcall Calling Convention}). - -@node Stdcall Calling Convention -@subsection @code{Stdcall} Calling Convention - -@noindent -This convention, which was the calling convention used for Pascal -programs, is used by Microsoft for all the routines in the Win32 API for -efficiency reasons. It must be used to import any routine for which this -convention was specified. - -In the @code{Stdcall} calling convention subprogram parameters are pushed -on the stack by the caller from right to left. The callee (and not the -caller) is in charge of cleaning the stack on routine exit. In addition, -the name of a routine with @code{Stdcall} calling convention is mangled by -adding a leading underscore (as for the @code{C} calling convention) and a -trailing @code{@@}@code{@var{nn}}, where @var{nn} is the overall size (in -bytes) of the parameters passed to the routine. - -The name to use on the Ada side when importing a C routine with a -@code{Stdcall} calling convention is the name of the C routine. The leading -underscore and trailing @code{@@}@code{@var{nn}} are added automatically by -the compiler. For instance the Win32 function: - -@smallexample -@b{APIENTRY} int get_val (long); -@end smallexample - -@noindent -should be imported from Ada as follows: - -@smallexample @c ada -@group -@b{function} Get_Val (V : Interfaces.C.long) @b{return} Interfaces.C.int; -@b{pragma} Import (Stdcall, Get_Val); ---@i{ On the x86 a long is 4 bytes, so the Link_Name is "_get_val@@4"} -@end group -@end smallexample - -@noindent -As for the @code{C} calling convention, when the @code{External_Name} -parameter is missing, it is taken to be the name of the Ada entity in lower -case. If instead of writing the above import pragma you write: - -@smallexample @c ada -@group -@b{function} Get_Val (V : Interfaces.C.long) @b{return} Interfaces.C.int; -@b{pragma} Import (Stdcall, Get_Val, External_Name => "retrieve_val"); -@end group -@end smallexample - -@noindent -then the imported routine is @code{_retrieve_val@@4}. However, if instead -of specifying the @code{External_Name} parameter you specify the -@code{Link_Name} as in the following example: - -@smallexample @c ada -@group -@b{function} Get_Val (V : Interfaces.C.long) @b{return} Interfaces.C.int; -@b{pragma} Import (Stdcall, Get_Val, Link_Name => "retrieve_val"); -@end group -@end smallexample - -@noindent -then the imported routine is @code{retrieve_val}, that is, there is no -decoration at all. No leading underscore and no Stdcall suffix -@code{@@}@code{@var{nn}}. - -@noindent -This is especially important as in some special cases a DLL's entry -point name lacks a trailing @code{@@}@code{@var{nn}} while the exported -name generated for a call has it. - -@noindent -It is also possible to import variables defined in a DLL by using an -import pragma for a variable. As an example, if a DLL contains a -variable defined as: - -@smallexample -int my_var; -@end smallexample - -@noindent -then, to access this variable from Ada you should write: - -@smallexample @c ada -@group -My_Var : Interfaces.C.int; -@b{pragma} Import (Stdcall, My_Var); -@end group -@end smallexample - -@noindent -Note that to ease building cross-platform bindings this convention -will be handled as a @code{C} calling convention on non-Windows platforms. - -@node Win32 Calling Convention -@subsection @code{Win32} Calling Convention - -@noindent -This convention, which is GNAT-specific is fully equivalent to the -@code{Stdcall} calling convention described above. - -@node DLL Calling Convention -@subsection @code{DLL} Calling Convention - -@noindent -This convention, which is GNAT-specific is fully equivalent to the -@code{Stdcall} calling convention described above. - -@node Introduction to Dynamic Link Libraries (DLLs) -@section Introduction to Dynamic Link Libraries (DLLs) -@findex DLL - -@noindent -A Dynamically Linked Library (DLL) is a library that can be shared by -several applications running under Windows. A DLL can contain any number of -routines and variables. - -One advantage of DLLs is that you can change and enhance them without -forcing all the applications that depend on them to be relinked or -recompiled. However, you should be aware than all calls to DLL routines are -slower since, as you will understand below, such calls are indirect. - -To illustrate the remainder of this section, suppose that an application -wants to use the services of a DLL @file{API.dll}. To use the services -provided by @file{API.dll} you must statically link against the DLL or -an import library which contains a jump table with an entry for each -routine and variable exported by the DLL. In the Microsoft world this -import library is called @file{API.lib}. When using GNAT this import -library is called either @file{libAPI.dll.a}, @file{libapi.dll.a}, -@file{libAPI.a} or @file{libapi.a} (names are case insensitive). - -After you have linked your application with the DLL or the import library -and you run your application, here is what happens: - -@enumerate -@item -Your application is loaded into memory. - -@item -The DLL @file{API.dll} is mapped into the address space of your -application. This means that: - -@itemize @bullet -@item -The DLL will use the stack of the calling thread. - -@item -The DLL will use the virtual address space of the calling process. - -@item -The DLL will allocate memory from the virtual address space of the calling -process. - -@item -Handles (pointers) can be safely exchanged between routines in the DLL -routines and routines in the application using the DLL. -@end itemize - -@item -The entries in the jump table (from the import library @file{libAPI.dll.a} -or @file{API.lib} or automatically created when linking against a DLL) -which is part of your application are initialized with the addresses -of the routines and variables in @file{API.dll}. - -@item -If present in @file{API.dll}, routines @code{DllMain} or -@code{DllMainCRTStartup} are invoked. These routines typically contain -the initialization code needed for the well-being of the routines and -variables exported by the DLL. -@end enumerate - -@noindent -There is an additional point which is worth mentioning. In the Windows -world there are two kind of DLLs: relocatable and non-relocatable -DLLs. Non-relocatable DLLs can only be loaded at a very specific address -in the target application address space. If the addresses of two -non-relocatable DLLs overlap and these happen to be used by the same -application, a conflict will occur and the application will run -incorrectly. Hence, when possible, it is always preferable to use and -build relocatable DLLs. Both relocatable and non-relocatable DLLs are -supported by GNAT. Note that the @option{-s} linker option (see GNU Linker -User's Guide) removes the debugging symbols from the DLL but the DLL can -still be relocated. - -As a side note, an interesting difference between Microsoft DLLs and -Unix shared libraries, is the fact that on most Unix systems all public -routines are exported by default in a Unix shared library, while under -Windows it is possible (but not required) to list exported routines in -a definition file (@pxref{The Definition File}). - -@node Using DLLs with GNAT -@section Using DLLs with GNAT - -@menu -* Creating an Ada Spec for the DLL Services:: -* Creating an Import Library:: -@end menu - -@noindent -To use the services of a DLL, say @file{API.dll}, in your Ada application -you must have: - -@enumerate -@item -The Ada spec for the routines and/or variables you want to access in -@file{API.dll}. If not available this Ada spec must be built from the C/C++ -header files provided with the DLL. - -@item -The import library (@file{libAPI.dll.a} or @file{API.lib}). As previously -mentioned an import library is a statically linked library containing the -import table which will be filled at load time to point to the actual -@file{API.dll} routines. Sometimes you don't have an import library for the -DLL you want to use. The following sections will explain how to build -one. Note that this is optional. - -@item -The actual DLL, @file{API.dll}. -@end enumerate - -@noindent -Once you have all the above, to compile an Ada application that uses the -services of @file{API.dll} and whose main subprogram is @code{My_Ada_App}, -you simply issue the command - -@smallexample -$ gnatmake my_ada_app -largs -lAPI -@end smallexample - -@noindent -The argument @option{-largs -lAPI} at the end of the @command{gnatmake} command -tells the GNAT linker to look for an import library. The linker will -look for a library name in this specific order: - -@enumerate -@item @file{libAPI.dll.a} -@item @file{API.dll.a} -@item @file{libAPI.a} -@item @file{API.lib} -@item @file{libAPI.dll} -@item @file{API.dll} -@end enumerate - -The first three are the GNU style import libraries. The third is the -Microsoft style import libraries. The last two are the actual DLL names. - -Note that if the Ada package spec for @file{API.dll} contains the -following pragma - -@smallexample @c ada -@b{pragma} Linker_Options ("-lAPI"); -@end smallexample - -@noindent -you do not have to add @option{-largs -lAPI} at the end of the -@command{gnatmake} command. - -If any one of the items above is missing you will have to create it -yourself. The following sections explain how to do so using as an -example a fictitious DLL called @file{API.dll}. - -@node Creating an Ada Spec for the DLL Services -@subsection Creating an Ada Spec for the DLL Services - -@noindent -A DLL typically comes with a C/C++ header file which provides the -definitions of the routines and variables exported by the DLL. The Ada -equivalent of this header file is a package spec that contains definitions -for the imported entities. If the DLL you intend to use does not come with -an Ada spec you have to generate one such spec yourself. For example if -the header file of @file{API.dll} is a file @file{api.h} containing the -following two definitions: - -@smallexample -@group -@cartouche -int some_var; -int get (char *); -@end cartouche -@end group -@end smallexample - -@noindent -then the equivalent Ada spec could be: - -@smallexample @c ada -@group -@cartouche -@b{with} Interfaces.C.Strings; -@b{package} API @b{is} - @b{use} Interfaces; - - Some_Var : C.int; - @b{function} Get (Str : C.Strings.Chars_Ptr) @b{return} C.int; - -@b{private} - @b{pragma} Import (C, Get); - @b{pragma} Import (DLL, Some_Var); -@b{end} API; -@end cartouche -@end group -@end smallexample - -@node Creating an Import Library -@subsection Creating an Import Library -@cindex Import library - -@menu -* The Definition File:: -* GNAT-Style Import Library:: -* Microsoft-Style Import Library:: -@end menu - -@noindent -If a Microsoft-style import library @file{API.lib} or a GNAT-style -import library @file{libAPI.dll.a} or @file{libAPI.a} is available -with @file{API.dll} you can skip this section. You can also skip this -section if @file{API.dll} or @file{libAPI.dll} is built with GNU tools -as in this case it is possible to link directly against the -DLL. Otherwise read on. - -@node The Definition File -@subsubsection The Definition File -@cindex Definition file -@findex .def - -@noindent -As previously mentioned, and unlike Unix systems, the list of symbols -that are exported from a DLL must be provided explicitly in Windows. -The main goal of a definition file is precisely that: list the symbols -exported by a DLL. A definition file (usually a file with a @code{.def} -suffix) has the following structure: - -@smallexample -@group -@cartouche -@r{[}LIBRARY @var{name}@r{]} -@r{[}DESCRIPTION @var{string}@r{]} -EXPORTS - @var{symbol1} - @var{symbol2} - @dots{} -@end cartouche -@end group -@end smallexample - -@table @code -@item LIBRARY @var{name} -This section, which is optional, gives the name of the DLL. - -@item DESCRIPTION @var{string} -This section, which is optional, gives a description string that will be -embedded in the import library. - -@item EXPORTS -This section gives the list of exported symbols (procedures, functions or -variables). For instance in the case of @file{API.dll} the @code{EXPORTS} -section of @file{API.def} looks like: - -@smallexample -@group -@cartouche -EXPORTS - some_var - get -@end cartouche -@end group -@end smallexample -@end table - -@noindent -Note that you must specify the correct suffix (@code{@@}@code{@var{nn}}) -(@pxref{Windows Calling Conventions}) for a Stdcall -calling convention function in the exported symbols list. - -@noindent -There can actually be other sections in a definition file, but these -sections are not relevant to the discussion at hand. - -@node GNAT-Style Import Library -@subsubsection GNAT-Style Import Library - -@noindent -To create a static import library from @file{API.dll} with the GNAT tools -you should proceed as follows: - -@enumerate -@item -Create the definition file @file{API.def} (@pxref{The Definition File}). -For that use the @code{dll2def} tool as follows: - -@smallexample -$ dll2def API.dll > API.def -@end smallexample - -@noindent -@code{dll2def} is a very simple tool: it takes as input a DLL and prints -to standard output the list of entry points in the DLL. Note that if -some routines in the DLL have the @code{Stdcall} convention -(@pxref{Windows Calling Conventions}) with stripped @code{@@}@var{nn} -suffix then you'll have to edit @file{api.def} to add it, and specify -@option{-k} to @command{gnatdll} when creating the import library. - -@noindent -Here are some hints to find the right @code{@@}@var{nn} suffix. - -@enumerate -@item -If you have the Microsoft import library (.lib), it is possible to get -the right symbols by using Microsoft @code{dumpbin} tool (see the -corresponding Microsoft documentation for further details). - -@smallexample -$ dumpbin /exports api.lib -@end smallexample - -@item -If you have a message about a missing symbol at link time the compiler -tells you what symbol is expected. You just have to go back to the -definition file and add the right suffix. -@end enumerate - -@item -Build the import library @code{libAPI.dll.a}, using @code{gnatdll} -(@pxref{Using gnatdll}) as follows: - -@smallexample -$ gnatdll -e API.def -d API.dll -@end smallexample - -@noindent -@code{gnatdll} takes as input a definition file @file{API.def} and the -name of the DLL containing the services listed in the definition file -@file{API.dll}. The name of the static import library generated is -computed from the name of the definition file as follows: if the -definition file name is @var{xyz}@code{.def}, the import library name will -be @code{lib}@var{xyz}@code{.a}. Note that in the previous example option -@option{-e} could have been removed because the name of the definition -file (before the ``@code{.def}'' suffix) is the same as the name of the -DLL (@pxref{Using gnatdll} for more information about @code{gnatdll}). -@end enumerate - -@node Microsoft-Style Import Library -@subsubsection Microsoft-Style Import Library - -@noindent -With GNAT you can either use a GNAT-style or Microsoft-style import -library. A Microsoft import library is needed only if you plan to make an -Ada DLL available to applications developed with Microsoft -tools (@pxref{Mixed-Language Programming on Windows}). - -To create a Microsoft-style import library for @file{API.dll} you -should proceed as follows: - -@enumerate -@item -Create the definition file @file{API.def} from the DLL. For this use either -the @code{dll2def} tool as described above or the Microsoft @code{dumpbin} -tool (see the corresponding Microsoft documentation for further details). - -@item -Build the actual import library using Microsoft's @code{lib} utility: - -@smallexample -$ lib -machine:IX86 -def:API.def -out:API.lib -@end smallexample - -@noindent -If you use the above command the definition file @file{API.def} must -contain a line giving the name of the DLL: - -@smallexample -LIBRARY "API" -@end smallexample - -@noindent -See the Microsoft documentation for further details about the usage of -@code{lib}. -@end enumerate - -@node Building DLLs with GNAT Project files -@section Building DLLs with GNAT Project files -@cindex DLLs, building - -@noindent -There is nothing specific to Windows in the build process. -@pxref{Library Projects}. - -@noindent -Due to a system limitation, it is not possible under Windows to create threads -when inside the @code{DllMain} routine which is used for auto-initialization -of shared libraries, so it is not possible to have library level tasks in SALs. - -@node Building DLLs with GNAT -@section Building DLLs with GNAT -@cindex DLLs, building - -@noindent -This section explain how to build DLLs using the GNAT built-in DLL -support. With the following procedure it is straight forward to build -and use DLLs with GNAT. - -@enumerate - -@item building object files - -The first step is to build all objects files that are to be included -into the DLL. This is done by using the standard @command{gnatmake} tool. - -@item building the DLL - -To build the DLL you must use @command{gcc}'s @option{-shared} and -@option{-shared-libgcc} options. It is quite simple to use this method: - -@smallexample -$ gcc -shared -shared-libgcc -o api.dll obj1.o obj2.o @dots{} -@end smallexample - -It is important to note that in this case all symbols found in the -object files are automatically exported. It is possible to restrict -the set of symbols to export by passing to @command{gcc} a definition -file, @pxref{The Definition File}. For example: - -@smallexample -$ gcc -shared -shared-libgcc -o api.dll api.def obj1.o obj2.o @dots{} -@end smallexample - -If you use a definition file you must export the elaboration procedures -for every package that required one. Elaboration procedures are named -using the package name followed by "_E". - -@item preparing DLL to be used - -For the DLL to be used by client programs the bodies must be hidden -from it and the .ali set with read-only attribute. This is very important -otherwise GNAT will recompile all packages and will not actually use -the code in the DLL. For example: - -@smallexample -$ mkdir apilib -$ copy *.ads *.ali api.dll apilib -$ attrib +R apilib\*.ali -@end smallexample - -@end enumerate - -At this point it is possible to use the DLL by directly linking -against it. Note that you must use the GNAT shared runtime when using -GNAT shared libraries. This is achieved by using @option{-shared} binder's -option. - -@smallexample -$ gnatmake main -Iapilib -bargs -shared -largs -Lapilib -lAPI -@end smallexample - -@node Building DLLs with gnatdll -@section Building DLLs with gnatdll -@cindex DLLs, building - -@menu -* Limitations When Using Ada DLLs from Ada:: -* Exporting Ada Entities:: -* Ada DLLs and Elaboration:: -* Ada DLLs and Finalization:: -* Creating a Spec for Ada DLLs:: -* Creating the Definition File:: -* Using gnatdll:: -@end menu - -@noindent -Note that it is preferred to use GNAT Project files -(@pxref{Building DLLs with GNAT Project files}) or the built-in GNAT -DLL support (@pxref{Building DLLs with GNAT}) or to build DLLs. - -This section explains how to build DLLs containing Ada code using -@code{gnatdll}. These DLLs will be referred to as Ada DLLs in the -remainder of this section. - -The steps required to build an Ada DLL that is to be used by Ada as well as -non-Ada applications are as follows: - -@enumerate -@item -You need to mark each Ada @i{entity} exported by the DLL with a @code{C} or -@code{Stdcall} calling convention to avoid any Ada name mangling for the -entities exported by the DLL (@pxref{Exporting Ada Entities}). You can -skip this step if you plan to use the Ada DLL only from Ada applications. - -@item -Your Ada code must export an initialization routine which calls the routine -@code{adainit} generated by @command{gnatbind} to perform the elaboration of -the Ada code in the DLL (@pxref{Ada DLLs and Elaboration}). The initialization -routine exported by the Ada DLL must be invoked by the clients of the DLL -to initialize the DLL. - -@item -When useful, the DLL should also export a finalization routine which calls -routine @code{adafinal} generated by @command{gnatbind} to perform the -finalization of the Ada code in the DLL (@pxref{Ada DLLs and Finalization}). -The finalization routine exported by the Ada DLL must be invoked by the -clients of the DLL when the DLL services are no further needed. - -@item -You must provide a spec for the services exported by the Ada DLL in each -of the programming languages to which you plan to make the DLL available. - -@item -You must provide a definition file listing the exported entities -(@pxref{The Definition File}). - -@item -Finally you must use @code{gnatdll} to produce the DLL and the import -library (@pxref{Using gnatdll}). -@end enumerate - -@noindent -Note that a relocatable DLL stripped using the @code{strip} -binutils tool will not be relocatable anymore. To build a DLL without -debug information pass @code{-largs -s} to @code{gnatdll}. This -restriction does not apply to a DLL built using a Library Project. -@pxref{Library Projects}. - -@node Limitations When Using Ada DLLs from Ada -@subsection Limitations When Using Ada DLLs from Ada - -@noindent -When using Ada DLLs from Ada applications there is a limitation users -should be aware of. Because on Windows the GNAT run time is not in a DLL of -its own, each Ada DLL includes a part of the GNAT run time. Specifically, -each Ada DLL includes the services of the GNAT run time that are necessary -to the Ada code inside the DLL. As a result, when an Ada program uses an -Ada DLL there are two independent GNAT run times: one in the Ada DLL and -one in the main program. - -It is therefore not possible to exchange GNAT run-time objects between the -Ada DLL and the main Ada program. Example of GNAT run-time objects are file -handles (e.g.@: @code{Text_IO.File_Type}), tasks types, protected objects -types, etc. - -It is completely safe to exchange plain elementary, array or record types, -Windows object handles, etc. - -@node Exporting Ada Entities -@subsection Exporting Ada Entities -@cindex Export table - -@noindent -Building a DLL is a way to encapsulate a set of services usable from any -application. As a result, the Ada entities exported by a DLL should be -exported with the @code{C} or @code{Stdcall} calling conventions to avoid -any Ada name mangling. As an example here is an Ada package -@code{API}, spec and body, exporting two procedures, a function, and a -variable: - -@smallexample @c ada -@group -@cartouche -@b{with} Interfaces.C; @b{use} Interfaces; -@b{package} API @b{is} - Count : C.int := 0; - @b{function} Factorial (Val : C.int) @b{return} C.int; - - @b{procedure} Initialize_API; - @b{procedure} Finalize_API; - --@i{ Initialization & Finalization routines. More in the next section.} -@b{private} - @b{pragma} Export (C, Initialize_API); - @b{pragma} Export (C, Finalize_API); - @b{pragma} Export (C, Count); - @b{pragma} Export (C, Factorial); -@b{end} API; -@end cartouche -@end group -@end smallexample - -@smallexample @c ada -@group -@cartouche -@b{package} @b{body} API @b{is} - @b{function} Factorial (Val : C.int) @b{return} C.int @b{is} - Fact : C.int := 1; - @b{begin} - Count := Count + 1; - @b{for} K @b{in} 1 .. Val @b{loop} - Fact := Fact * K; - @b{end} @b{loop}; - @b{return} Fact; - @b{end} Factorial; - - @b{procedure} Initialize_API @b{is} - @b{procedure} Adainit; - @b{pragma} Import (C, Adainit); - @b{begin} - Adainit; - @b{end} Initialize_API; - - @b{procedure} Finalize_API @b{is} - @b{procedure} Adafinal; - @b{pragma} Import (C, Adafinal); - @b{begin} - Adafinal; - @b{end} Finalize_API; -@b{end} API; -@end cartouche -@end group -@end smallexample - -@noindent -If the Ada DLL you are building will only be used by Ada applications -you do not have to export Ada entities with a @code{C} or @code{Stdcall} -convention. As an example, the previous package could be written as -follows: - -@smallexample @c ada -@group -@cartouche -@b{package} API @b{is} - Count : Integer := 0; - @b{function} Factorial (Val : Integer) @b{return} Integer; - - @b{procedure} Initialize_API; - @b{procedure} Finalize_API; - --@i{ Initialization and Finalization routines.} -@b{end} API; -@end cartouche -@end group -@end smallexample - -@smallexample @c ada -@group -@cartouche -@b{package} @b{body} API @b{is} - @b{function} Factorial (Val : Integer) @b{return} Integer @b{is} - Fact : Integer := 1; - @b{begin} - Count := Count + 1; - @b{for} K @b{in} 1 .. Val @b{loop} - Fact := Fact * K; - @b{end} @b{loop}; - @b{return} Fact; - @b{end} Factorial; - - @dots{} - --@i{ The remainder of this package body is unchanged.} -@b{end} API; -@end cartouche -@end group -@end smallexample - -@noindent -Note that if you do not export the Ada entities with a @code{C} or -@code{Stdcall} convention you will have to provide the mangled Ada names -in the definition file of the Ada DLL -(@pxref{Creating the Definition File}). - -@node Ada DLLs and Elaboration -@subsection Ada DLLs and Elaboration -@cindex DLLs and elaboration - -@noindent -The DLL that you are building contains your Ada code as well as all the -routines in the Ada library that are needed by it. The first thing a -user of your DLL must do is elaborate the Ada code -(@pxref{Elaboration Order Handling in GNAT}). - -To achieve this you must export an initialization routine -(@code{Initialize_API} in the previous example), which must be invoked -before using any of the DLL services. This elaboration routine must call -the Ada elaboration routine @code{adainit} generated by the GNAT binder -(@pxref{Binding with Non-Ada Main Programs}). See the body of -@code{Initialize_Api} for an example. Note that the GNAT binder is -automatically invoked during the DLL build process by the @code{gnatdll} -tool (@pxref{Using gnatdll}). - -When a DLL is loaded, Windows systematically invokes a routine called -@code{DllMain}. It would therefore be possible to call @code{adainit} -directly from @code{DllMain} without having to provide an explicit -initialization routine. Unfortunately, it is not possible to call -@code{adainit} from the @code{DllMain} if your program has library level -tasks because access to the @code{DllMain} entry point is serialized by -the system (that is, only a single thread can execute ``through'' it at a -time), which means that the GNAT run time will deadlock waiting for the -newly created task to complete its initialization. - -@node Ada DLLs and Finalization -@subsection Ada DLLs and Finalization -@cindex DLLs and finalization - -@noindent -When the services of an Ada DLL are no longer needed, the client code should -invoke the DLL finalization routine, if available. The DLL finalization -routine is in charge of releasing all resources acquired by the DLL. In the -case of the Ada code contained in the DLL, this is achieved by calling -routine @code{adafinal} generated by the GNAT binder -(@pxref{Binding with Non-Ada Main Programs}). -See the body of @code{Finalize_Api} for an -example. As already pointed out the GNAT binder is automatically invoked -during the DLL build process by the @code{gnatdll} tool -(@pxref{Using gnatdll}). - -@node Creating a Spec for Ada DLLs -@subsection Creating a Spec for Ada DLLs - -@noindent -To use the services exported by the Ada DLL from another programming -language (e.g.@: C), you have to translate the specs of the exported Ada -entities in that language. For instance in the case of @code{API.dll}, -the corresponding C header file could look like: - -@smallexample -@group -@cartouche -extern int *_imp__count; -#define count (*_imp__count) -int factorial (int); -@end cartouche -@end group -@end smallexample - -@noindent -It is important to understand that when building an Ada DLL to be used by -other Ada applications, you need two different specs for the packages -contained in the DLL: one for building the DLL and the other for using -the DLL. This is because the @code{DLL} calling convention is needed to -use a variable defined in a DLL, but when building the DLL, the variable -must have either the @code{Ada} or @code{C} calling convention. As an -example consider a DLL comprising the following package @code{API}: - -@smallexample @c ada -@group -@cartouche -@b{package} API @b{is} - Count : Integer := 0; - @dots{} - --@i{ Remainder of the package omitted.} -@b{end} API; -@end cartouche -@end group -@end smallexample - -@noindent -After producing a DLL containing package @code{API}, the spec that -must be used to import @code{API.Count} from Ada code outside of the -DLL is: - -@smallexample @c ada -@group -@cartouche -@b{package} API @b{is} - Count : Integer; - @b{pragma} Import (DLL, Count); -@b{end} API; -@end cartouche -@end group -@end smallexample - -@node Creating the Definition File -@subsection Creating the Definition File - -@noindent -The definition file is the last file needed to build the DLL. It lists -the exported symbols. As an example, the definition file for a DLL -containing only package @code{API} (where all the entities are exported -with a @code{C} calling convention) is: - -@smallexample -@group -@cartouche -EXPORTS - count - factorial - finalize_api - initialize_api -@end cartouche -@end group -@end smallexample - -@noindent -If the @code{C} calling convention is missing from package @code{API}, -then the definition file contains the mangled Ada names of the above -entities, which in this case are: - -@smallexample -@group -@cartouche -EXPORTS - api__count - api__factorial - api__finalize_api - api__initialize_api -@end cartouche -@end group -@end smallexample - -@node Using gnatdll -@subsection Using @code{gnatdll} -@findex gnatdll - -@menu -* gnatdll Example:: -* gnatdll behind the Scenes:: -* Using dlltool:: -@end menu - -@noindent -@code{gnatdll} is a tool to automate the DLL build process once all the Ada -and non-Ada sources that make up your DLL have been compiled. -@code{gnatdll} is actually in charge of two distinct tasks: build the -static import library for the DLL and the actual DLL. The form of the -@code{gnatdll} command is - -@smallexample -@cartouche -@c $ gnatdll @ovar{switches} @var{list-of-files} @r{[}-largs @var{opts}@r{]} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ gnatdll @r{[}@var{switches}@r{]} @var{list-of-files} @r{[}-largs @var{opts}@r{]} -@end cartouche -@end smallexample - -@noindent -where @var{list-of-files} is a list of ALI and object files. The object -file list must be the exact list of objects corresponding to the non-Ada -sources whose services are to be included in the DLL. The ALI file list -must be the exact list of ALI files for the corresponding Ada sources -whose services are to be included in the DLL. If @var{list-of-files} is -missing, only the static import library is generated. - -@noindent -You may specify any of the following switches to @code{gnatdll}: - -@table @code -@c @item -a@ovar{address} -@c Expanding @ovar macro inline (explanation in macro def comments) -@item -a@r{[}@var{address}@r{]} -@cindex @option{-a} (@code{gnatdll}) -Build a non-relocatable DLL at @var{address}. If @var{address} is not -specified the default address @var{0x11000000} will be used. By default, -when this switch is missing, @code{gnatdll} builds relocatable DLL. We -advise the reader to build relocatable DLL. - -@item -b @var{address} -@cindex @option{-b} (@code{gnatdll}) -Set the relocatable DLL base address. By default the address is -@code{0x11000000}. - -@item -bargs @var{opts} -@cindex @option{-bargs} (@code{gnatdll}) -Binder options. Pass @var{opts} to the binder. - -@item -d @var{dllfile} -@cindex @option{-d} (@code{gnatdll}) -@var{dllfile} is the name of the DLL. This switch must be present for -@code{gnatdll} to do anything. The name of the generated import library is -obtained algorithmically from @var{dllfile} as shown in the following -example: if @var{dllfile} is @code{xyz.dll}, the import library name is -@code{libxyz.dll.a}. The name of the definition file to use (if not specified -by option @option{-e}) is obtained algorithmically from @var{dllfile} -as shown in the following example: -if @var{dllfile} is @code{xyz.dll}, the definition -file used is @code{xyz.def}. - -@item -e @var{deffile} -@cindex @option{-e} (@code{gnatdll}) -@var{deffile} is the name of the definition file. - -@item -g -@cindex @option{-g} (@code{gnatdll}) -Generate debugging information. This information is stored in the object -file and copied from there to the final DLL file by the linker, -where it can be read by the debugger. You must use the -@option{-g} switch if you plan on using the debugger or the symbolic -stack traceback. - -@item -h -@cindex @option{-h} (@code{gnatdll}) -Help mode. Displays @code{gnatdll} switch usage information. - -@item -Idir -@cindex @option{-I} (@code{gnatdll}) -Direct @code{gnatdll} to search the @var{dir} directory for source and -object files needed to build the DLL. -(@pxref{Search Paths and the Run-Time Library (RTL)}). - -@item -k -@cindex @option{-k} (@code{gnatdll}) -Removes the @code{@@}@var{nn} suffix from the import library's exported -names, but keeps them for the link names. You must specify this -option if you want to use a @code{Stdcall} function in a DLL for which -the @code{@@}@var{nn} suffix has been removed. This is the case for most -of the Windows NT DLL for example. This option has no effect when -@option{-n} option is specified. - -@item -l @var{file} -@cindex @option{-l} (@code{gnatdll}) -The list of ALI and object files used to build the DLL are listed in -@var{file}, instead of being given in the command line. Each line in -@var{file} contains the name of an ALI or object file. - -@item -n -@cindex @option{-n} (@code{gnatdll}) -No Import. Do not create the import library. - -@item -q -@cindex @option{-q} (@code{gnatdll}) -Quiet mode. Do not display unnecessary messages. - -@item -v -@cindex @option{-v} (@code{gnatdll}) -Verbose mode. Display extra information. - -@item -largs @var{opts} -@cindex @option{-largs} (@code{gnatdll}) -Linker options. Pass @var{opts} to the linker. -@end table - -@node gnatdll Example -@subsubsection @code{gnatdll} Example - -@noindent -As an example the command to build a relocatable DLL from @file{api.adb} -once @file{api.adb} has been compiled and @file{api.def} created is - -@smallexample -$ gnatdll -d api.dll api.ali -@end smallexample - -@noindent -The above command creates two files: @file{libapi.dll.a} (the import -library) and @file{api.dll} (the actual DLL). If you want to create -only the DLL, just type: - -@smallexample -$ gnatdll -d api.dll -n api.ali -@end smallexample - -@noindent -Alternatively if you want to create just the import library, type: - -@smallexample -$ gnatdll -d api.dll -@end smallexample - -@node gnatdll behind the Scenes -@subsubsection @code{gnatdll} behind the Scenes -@noindent -This section details the steps involved in creating a DLL. @code{gnatdll} -does these steps for you. Unless you are interested in understanding what -goes on behind the scenes, you should skip this section. - -We use the previous example of a DLL containing the Ada package @code{API}, -to illustrate the steps necessary to build a DLL. The starting point is a -set of objects that will make up the DLL and the corresponding ALI -files. In the case of this example this means that @file{api.o} and -@file{api.ali} are available. To build a relocatable DLL, @code{gnatdll} does -the following: - -@enumerate -@item -@code{gnatdll} builds the base file (@file{api.base}). A base file gives -the information necessary to generate relocation information for the -DLL. - -@smallexample -@group -$ gnatbind -n api -$ gnatlink api -o api.jnk -mdll -Wl,--base-file,api.base -@end group -@end smallexample - -@noindent -In addition to the base file, the @command{gnatlink} command generates an -output file @file{api.jnk} which can be discarded. The @option{-mdll} switch -asks @command{gnatlink} to generate the routines @code{DllMain} and -@code{DllMainCRTStartup} that are called by the Windows loader when the DLL -is loaded into memory. - -@item -@code{gnatdll} uses @code{dlltool} (@pxref{Using dlltool}) to build the -export table (@file{api.exp}). The export table contains the relocation -information in a form which can be used during the final link to ensure -that the Windows loader is able to place the DLL anywhere in memory. - -@smallexample -@group -$ dlltool --dllname api.dll --def api.def --base-file api.base \ - --output-exp api.exp -@end group -@end smallexample - -@item -@code{gnatdll} builds the base file using the new export table. Note that -@command{gnatbind} must be called once again since the binder generated file -has been deleted during the previous call to @command{gnatlink}. - -@smallexample -@group -$ gnatbind -n api -$ gnatlink api -o api.jnk api.exp -mdll - -Wl,--base-file,api.base -@end group -@end smallexample - -@item -@code{gnatdll} builds the new export table using the new base file and -generates the DLL import library @file{libAPI.dll.a}. - -@smallexample -@group -$ dlltool --dllname api.dll --def api.def --base-file api.base \ - --output-exp api.exp --output-lib libAPI.a -@end group -@end smallexample - -@item -Finally @code{gnatdll} builds the relocatable DLL using the final export -table. - -@smallexample -@group -$ gnatbind -n api -$ gnatlink api api.exp -o api.dll -mdll -@end group -@end smallexample +@node GNU Free Documentation License,Index,Inline Assembler,Top +@anchor{share/gnu_free_documentation_license gnu-fdl}@anchor{1}@anchor{share/gnu_free_documentation_license doc}@anchor{2de}@anchor{share/gnu_free_documentation_license gnu-free-documentation-license}@anchor{2df} +@chapter GNU Free Documentation License + + +Version 1.3, 3 November 2008 + +Copyright 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc +@indicateurl{http://fsf.org/} + +Everyone is permitted to copy and distribute verbatim copies of this +license document, but changing it is not allowed. + +@strong{Preamble} + +The purpose of this License is to make a manual, textbook, or other +functional and useful document "free" in the sense of freedom: to +assure everyone the effective freedom to copy and redistribute it, +with or without modifying it, either commercially or noncommercially. +Secondarily, this License preserves for the author and publisher a way +to get credit for their work, while not being considered responsible +for modifications made by others. + +This License is a kind of "copyleft", which means that derivative +works of the document must themselves be free in the same sense. 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These Warranty +Disclaimers are considered to be included by reference in this +License, but only as regards disclaiming warranties: any other +implication that these Warranty Disclaimers may have is void and has +no effect on the meaning of this License. + +@strong{2. VERBATIM COPYING} + +You may copy and distribute the Document in any medium, either +commercially or noncommercially, provided that this License, the +copyright notices, and the license notice saying this License applies +to the Document are reproduced in all copies, and that you add no other +conditions whatsoever to those of this License. You may not use +technical measures to obstruct or control the reading or further +copying of the copies you make or distribute. However, you may accept +compensation in exchange for copies. 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You may add other material on the covers in addition. +Copying with changes limited to the covers, as long as they preserve +the title of the Document and satisfy these conditions, can be treated +as verbatim copying in other respects. + +If the required texts for either cover are too voluminous to fit +legibly, you should put the first ones listed (as many as fit +reasonably) on the actual cover, and continue the rest onto adjacent +pages. + +If you publish or distribute Opaque copies of the Document numbering +more than 100, you must either include a machine-readable Transparent +copy along with each Opaque copy, or state in or with each Opaque copy +a computer-network location from which the general network-using +public has access to download using public-standard network protocols +a complete Transparent copy of the Document, free of added material. +If you use the latter option, you must take reasonably prudent steps, +when you begin distribution of Opaque copies in quantity, to ensure +that this Transparent copy will remain thus accessible at the stated +location until at least one year after the last time you distribute an +Opaque copy (directly or through your agents or retailers) of that +edition to the public. + +It is requested, but not required, that you contact the authors of the +Document well before redistributing any large number of copies, to give +them a chance to provide you with an updated version of the Document. + +@strong{4. MODIFICATIONS} + +You may copy and distribute a Modified Version of the Document under +the conditions of sections 2 and 3 above, provided that you release +the Modified Version under precisely this License, with the Modified +Version filling the role of the Document, thus licensing distribution +and modification of the Modified Version to whoever possesses a copy +of it. In addition, you must do these things in the Modified Version: + + +@enumerate A + +@item +Use in the Title Page (and on the covers, if any) a title distinct +from that of the Document, and from those of previous versions +(which should, if there were any, be listed in the History section +of the Document). You may use the same title as a previous version +if the original publisher of that version gives permission. + +@item +List on the Title Page, as authors, one or more persons or entities +responsible for authorship of the modifications in the Modified +Version, together with at least five of the principal authors of the +Document (all of its principal authors, if it has fewer than five), +unless they release you from this requirement. + +@item +State on the Title page the name of the publisher of the +Modified Version, as the publisher. + +@item +Preserve all the copyright notices of the Document. + +@item +Add an appropriate copyright notice for your modifications +adjacent to the other copyright notices. + +@item +Include, immediately after the copyright notices, a license notice +giving the public permission to use the Modified Version under the +terms of this License, in the form shown in the Addendum below. + +@item +Preserve in that license notice the full lists of Invariant Sections +and required Cover Texts given in the Document's license notice. + +@item +Include an unaltered copy of this License. + +@item +Preserve the section Entitled "History", Preserve its Title, and add +to it an item stating at least the title, year, new authors, and +publisher of the Modified Version as given on the Title Page. If +there is no section Entitled "History" in the Document, create one +stating the title, year, authors, and publisher of the Document as +given on its Title Page, then add an item describing the Modified +Version as stated in the previous sentence. + +@item +Preserve the network location, if any, given in the Document for +public access to a Transparent copy of the Document, and likewise +the network locations given in the Document for previous versions +it was based on. These may be placed in the "History" section. +You may omit a network location for a work that was published at +least four years before the Document itself, or if the original +publisher of the version it refers to gives permission. + +@item +For any section Entitled "Acknowledgements" or "Dedications", +Preserve the Title of the section, and preserve in the section all +the substance and tone of each of the contributor acknowledgements +and/or dedications given therein. + +@item +Preserve all the Invariant Sections of the Document, +unaltered in their text and in their titles. Section numbers +or the equivalent are not considered part of the section titles. + +@item +Delete any section Entitled "Endorsements". Such a section +may not be included in the Modified Version. + +@item +Do not retitle any existing section to be Entitled "Endorsements" +or to conflict in title with any Invariant Section. + +@item +Preserve any Warranty Disclaimers. @end enumerate -@node Using dlltool -@subsubsection Using @code{dlltool} - -@noindent -@code{dlltool} is the low-level tool used by @code{gnatdll} to build -DLLs and static import libraries. This section summarizes the most -common @code{dlltool} switches. The form of the @code{dlltool} command -is - -@smallexample -@c $ dlltool @ovar{switches} -@c Expanding @ovar macro inline (explanation in macro def comments) -$ dlltool @r{[}@var{switches}@r{]} -@end smallexample - -@noindent -@code{dlltool} switches include: - -@table @option -@item --base-file @var{basefile} -@cindex @option{--base-file} (@command{dlltool}) -Read the base file @var{basefile} generated by the linker. This switch -is used to create a relocatable DLL. - -@item --def @var{deffile} -@cindex @option{--def} (@command{dlltool}) -Read the definition file. - -@item --dllname @var{name} -@cindex @option{--dllname} (@command{dlltool}) -Gives the name of the DLL. This switch is used to embed the name of the -DLL in the static import library generated by @code{dlltool} with switch -@option{--output-lib}. - -@item -k -@cindex @option{-k} (@command{dlltool}) -Kill @code{@@}@var{nn} from exported names -(@pxref{Windows Calling Conventions} -for a discussion about @code{Stdcall}-style symbols. - -@item --help -@cindex @option{--help} (@command{dlltool}) -Prints the @code{dlltool} switches with a concise description. - -@item --output-exp @var{exportfile} -@cindex @option{--output-exp} (@command{dlltool}) -Generate an export file @var{exportfile}. The export file contains the -export table (list of symbols in the DLL) and is used to create the DLL. - -@item --output-lib @var{libfile} -@cindex @option{--output-lib} (@command{dlltool}) -Generate a static import library @var{libfile}. - -@item -v -@cindex @option{-v} (@command{dlltool}) -Verbose mode. - -@item --as @var{assembler-name} -@cindex @option{--as} (@command{dlltool}) -Use @var{assembler-name} as the assembler. The default is @code{as}. -@end table - -@node GNAT and Windows Resources -@section GNAT and Windows Resources -@cindex Resources, windows - -@menu -* Building Resources:: -* Compiling Resources:: -* Using Resources:: -@end menu - -@noindent -Resources are an easy way to add Windows specific objects to your -application. The objects that can be added as resources include: - -@itemize @bullet -@item menus - -@item accelerators - -@item dialog boxes - -@item string tables - -@item bitmaps - -@item cursors - -@item icons - -@item fonts - -@item version information -@end itemize - -For example, a version information resource can be defined as follow and -embedded into an executable or DLL: - -A version information resource can be used to embed information into an -executable or a DLL. These information can be viewed using the file properties -from the Windows Explorer. Here is an example of a version information -resource: - -@smallexample -@group -1 VERSIONINFO -FILEVERSION 1,0,0,0 -PRODUCTVERSION 1,0,0,0 -BEGIN - BLOCK "StringFileInfo" - BEGIN - BLOCK "080904E4" - BEGIN - VALUE "CompanyName", "My Company Name" - VALUE "FileDescription", "My application" - VALUE "FileVersion", "1.0" - VALUE "InternalName", "my_app" - VALUE "LegalCopyright", "My Name" - VALUE "OriginalFilename", "my_app.exe" - VALUE "ProductName", "My App" - VALUE "ProductVersion", "1.0" - END - END - - BLOCK "VarFileInfo" - BEGIN - VALUE "Translation", 0x809, 1252 - END -END -@end group -@end smallexample - -The value @code{0809} (langID) is for the U.K English language and -@code{04E4} (charsetID), which is equal to @code{1252} decimal, for -multilingual. - -@noindent -This section explains how to build, compile and use resources. Note that this -section does not cover all resource objects, for a complete description see -the corresponding Microsoft documentation. - -@node Building Resources -@subsection Building Resources -@cindex Resources, building - -@noindent -A resource file is an ASCII file. By convention resource files have an -@file{.rc} extension. -The easiest way to build a resource file is to use Microsoft tools -such as @code{imagedit.exe} to build bitmaps, icons and cursors and -@code{dlgedit.exe} to build dialogs. -It is always possible to build an @file{.rc} file yourself by writing a -resource script. - -It is not our objective to explain how to write a resource file. A -complete description of the resource script language can be found in the -Microsoft documentation. - -@node Compiling Resources -@subsection Compiling Resources -@findex rc -@findex windres -@cindex Resources, compiling - -@noindent -This section describes how to build a GNAT-compatible (COFF) object file -containing the resources. This is done using the Resource Compiler -@code{windres} as follows: - -@smallexample -$ windres -i myres.rc -o myres.o -@end smallexample - -@noindent -By default @code{windres} will run @command{gcc} to preprocess the @file{.rc} -file. You can specify an alternate preprocessor (usually named -@file{cpp.exe}) using the @code{windres} @option{--preprocessor} -parameter. A list of all possible options may be obtained by entering -the command @code{windres} @option{--help}. - -It is also possible to use the Microsoft resource compiler @code{rc.exe} -to produce a @file{.res} file (binary resource file). See the -corresponding Microsoft documentation for further details. In this case -you need to use @code{windres} to translate the @file{.res} file to a -GNAT-compatible object file as follows: - -@smallexample -$ windres -i myres.res -o myres.o -@end smallexample - -@node Using Resources -@subsection Using Resources -@cindex Resources, using - -@noindent -To include the resource file in your program just add the -GNAT-compatible object file for the resource(s) to the linker -arguments. With @command{gnatmake} this is done by using the @option{-largs} -option: - -@smallexample -$ gnatmake myprog -largs myres.o -@end smallexample - -@node Debugging a DLL -@section Debugging a DLL -@cindex DLL debugging - -@menu -* Program and DLL Both Built with GCC/GNAT:: -* Program Built with Foreign Tools and DLL Built with GCC/GNAT:: -@end menu - -@noindent -Debugging a DLL is similar to debugging a standard program. But -we have to deal with two different executable parts: the DLL and the -program that uses it. We have the following four possibilities: - -@enumerate 1 -@item -The program and the DLL are built with @code{GCC/GNAT}. -@item -The program is built with foreign tools and the DLL is built with -@code{GCC/GNAT}. -@item -The program is built with @code{GCC/GNAT} and the DLL is built with -foreign tools. -@end enumerate - -@noindent -In this section we address only cases one and two above. -There is no point in trying to debug -a DLL with @code{GNU/GDB}, if there is no GDB-compatible debugging -information in it. To do so you must use a debugger compatible with the -tools suite used to build the DLL. - -@node Program and DLL Both Built with GCC/GNAT -@subsection Program and DLL Both Built with GCC/GNAT - -@noindent -This is the simplest case. Both the DLL and the program have @code{GDB} -compatible debugging information. It is then possible to break anywhere in -the process. Let's suppose here that the main procedure is named -@code{ada_main} and that in the DLL there is an entry point named -@code{ada_dll}. - -@noindent -The DLL (@pxref{Introduction to Dynamic Link Libraries (DLLs)}) and -program must have been built with the debugging information (see GNAT -g -switch). Here are the step-by-step instructions for debugging it: - -@enumerate 1 -@item Launch @code{GDB} on the main program. - -@smallexample -$ gdb -nw ada_main -@end smallexample - -@item Start the program and stop at the beginning of the main procedure - -@smallexample -(gdb) start -@end smallexample - -@noindent -This step is required to be able to set a breakpoint inside the DLL. As long -as the program is not run, the DLL is not loaded. This has the -consequence that the DLL debugging information is also not loaded, so it is not -possible to set a breakpoint in the DLL. - -@item Set a breakpoint inside the DLL - -@smallexample -(gdb) break ada_dll -(gdb) cont -@end smallexample - -@end enumerate - -@noindent -At this stage a breakpoint is set inside the DLL. From there on -you can use the standard approach to debug the whole program -(@pxref{Running and Debugging Ada Programs}). - -@ignore -@c This used to work, probably because the DLLs were non-relocatable -@c keep this section around until the problem is sorted out. - -To break on the @code{DllMain} routine it is not possible to follow -the procedure above. At the time the program stop on @code{ada_main} -the @code{DllMain} routine as already been called. Either you can use -the procedure below @pxref{Debugging the DLL Directly} or this procedure: - -@enumerate 1 -@item Launch @code{GDB} on the main program. - -@smallexample -$ gdb ada_main -@end smallexample - -@item Load DLL symbols - -@smallexample -(gdb) add-sym api.dll -@end smallexample - -@item Set a breakpoint inside the DLL - -@smallexample -(gdb) break ada_dll.adb:45 -@end smallexample - -Note that at this point it is not possible to break using the routine symbol -directly as the program is not yet running. The solution is to break -on the proper line (break in @file{ada_dll.adb} line 45). - -@item Start the program - -@smallexample -(gdb) run -@end smallexample - -@end enumerate -@end ignore - -@node Program Built with Foreign Tools and DLL Built with GCC/GNAT -@subsection Program Built with Foreign Tools and DLL Built with GCC/GNAT - -@menu -* Debugging the DLL Directly:: -* Attaching to a Running Process:: -@end menu - -@noindent -In this case things are slightly more complex because it is not possible to -start the main program and then break at the beginning to load the DLL and the -associated DLL debugging information. It is not possible to break at the -beginning of the program because there is no @code{GDB} debugging information, -and therefore there is no direct way of getting initial control. This -section addresses this issue by describing some methods that can be used -to break somewhere in the DLL to debug it. - -@noindent -First suppose that the main procedure is named @code{main} (this is for -example some C code built with Microsoft Visual C) and that there is a -DLL named @code{test.dll} containing an Ada entry point named -@code{ada_dll}. - -@noindent -The DLL (@pxref{Introduction to Dynamic Link Libraries (DLLs)}) must have -been built with debugging information (see GNAT -g option). - -@node Debugging the DLL Directly -@subsubsection Debugging the DLL Directly - -@enumerate 1 -@item -Find out the executable starting address - -@smallexample -$ objdump --file-header main.exe -@end smallexample - -The starting address is reported on the last line. For example: - -@smallexample -main.exe: file format pei-i386 -architecture: i386, flags 0x0000010a: -EXEC_P, HAS_DEBUG, D_PAGED -start address 0x00401010 -@end smallexample - -@item -Launch the debugger on the executable. - -@smallexample -$ gdb main.exe -@end smallexample - -@item -Set a breakpoint at the starting address, and launch the program. - -@smallexample -$ (gdb) break *0x00401010 -$ (gdb) run -@end smallexample - -The program will stop at the given address. - -@item -Set a breakpoint on a DLL subroutine. - -@smallexample -(gdb) break ada_dll.adb:45 -@end smallexample - -Or if you want to break using a symbol on the DLL, you need first to -select the Ada language (language used by the DLL). - -@smallexample -(gdb) set language ada -(gdb) break ada_dll -@end smallexample - -@item -Continue the program. - -@smallexample -(gdb) cont -@end smallexample - -@noindent -This will run the program until it reaches the breakpoint that has been -set. From that point you can use the standard way to debug a program -as described in (@pxref{Running and Debugging Ada Programs}). - -@end enumerate - -@noindent -It is also possible to debug the DLL by attaching to a running process. - -@node Attaching to a Running Process -@subsubsection Attaching to a Running Process -@cindex DLL debugging, attach to process - -@noindent -With @code{GDB} it is always possible to debug a running process by -attaching to it. It is possible to debug a DLL this way. The limitation -of this approach is that the DLL must run long enough to perform the -attach operation. It may be useful for instance to insert a time wasting -loop in the code of the DLL to meet this criterion. - -@enumerate 1 - -@item Launch the main program @file{main.exe}. - -@smallexample -$ main -@end smallexample - -@item Use the Windows @i{Task Manager} to find the process ID. Let's say -that the process PID for @file{main.exe} is 208. - -@item Launch gdb. - -@smallexample -$ gdb -@end smallexample - -@item Attach to the running process to be debugged. - -@smallexample -(gdb) attach 208 -@end smallexample - -@item Load the process debugging information. - -@smallexample -(gdb) symbol-file main.exe -@end smallexample - -@item Break somewhere in the DLL. - -@smallexample -(gdb) break ada_dll -@end smallexample - -@item Continue process execution. - -@smallexample -(gdb) cont -@end smallexample - -@end enumerate - -@noindent -This last step will resume the process execution, and stop at -the breakpoint we have set. From there you can use the standard -approach to debug a program as described in -(@pxref{Running and Debugging Ada Programs}). - -@node Setting Stack Size from gnatlink -@section Setting Stack Size from @command{gnatlink} - -@noindent -It is possible to specify the program stack size at link time. On modern -versions of Windows, starting with XP, this is mostly useful to set the size of -the main stack (environment task). The other task stacks are set with pragma -Storage_Size or with the @command{gnatbind -d} command. - -Since older versions of Windows (2000, NT4, etc.) do not allow setting the -reserve size of individual tasks, the link-time stack size applies to all -tasks, and pragma Storage_Size has no effect. -In particular, Stack Overflow checks are made against this -link-time specified size. - -This setting can be done with -@command{gnatlink} using either: - -@itemize @bullet - -@item using @option{-Xlinker} linker option - -@smallexample -$ gnatlink hello -Xlinker --stack=0x10000,0x1000 -@end smallexample - -This sets the stack reserve size to 0x10000 bytes and the stack commit -size to 0x1000 bytes. - -@item using @option{-Wl} linker option - -@smallexample -$ gnatlink hello -Wl,--stack=0x1000000 -@end smallexample - -This sets the stack reserve size to 0x1000000 bytes. Note that with -@option{-Wl} option it is not possible to set the stack commit size -because the coma is a separator for this option. - -@end itemize - -@node Setting Heap Size from gnatlink -@section Setting Heap Size from @command{gnatlink} - -@noindent -Under Windows systems, it is possible to specify the program heap size from -@command{gnatlink} using either: - -@itemize @bullet - -@item using @option{-Xlinker} linker option - -@smallexample -$ gnatlink hello -Xlinker --heap=0x10000,0x1000 -@end smallexample - -This sets the heap reserve size to 0x10000 bytes and the heap commit -size to 0x1000 bytes. - -@item using @option{-Wl} linker option - -@smallexample -$ gnatlink hello -Wl,--heap=0x1000000 -@end smallexample - -This sets the heap reserve size to 0x1000000 bytes. Note that with -@option{-Wl} option it is not possible to set the heap commit size -because the coma is a separator for this option. - -@end itemize - -@node Mac OS Topics -@appendix Mac OS Topics -@cindex OS X - -@noindent -This chapter describes topics that are specific to Apple's OS X -platform. - -@menu -* Codesigning the Debugger:: -@end menu - -@node Codesigning the Debugger -@section Codesigning the Debugger - -@noindent -The Darwin Kernel requires the debugger to have special permissions -before it is allowed to control other processes. These permissions -are granted by codesigning the GDB executable. Without these -permissions, the debugger will report error messages such as: - -@smallexample -Starting program: /x/y/foo -Unable to find Mach task port for process-id 28885: (os/kern) failure (0x5). - (please check gdb is codesigned - see taskgated(8)) -@end smallexample - -Codesigning requires a certificate. The following procedure explains -how to create one: - -@itemize @bullet -@item Start the Keychain Access application (in -/Applications/Utilities/Keychain Access.app) - -@item Select the Keychain Access -> Certificate Assistant -> -Create a Certificate... menu - -@item Then: - -@itemize @bullet -@item Choose a name for the new certificate (this procedure will use -"gdb-cert" as an example) - -@item Set "Identity Type" to "Self Signed Root" - -@item Set "Certificate Type" to "Code Signing" - -@item Activate the "Let me override defaults" option - -@end itemize - -@item Click several times on "Continue" until the "Specify a Location -For The Certificate" screen appears, then set "Keychain" to "System" +If the Modified Version includes new front-matter sections or +appendices that qualify as Secondary Sections and contain no material +copied from the Document, you may at your option designate some or all +of these sections as invariant. To do this, add their titles to the +list of Invariant Sections in the Modified Version's license notice. +These titles must be distinct from any other section titles. + +You may add a section Entitled "Endorsements", provided it contains +nothing but endorsements of your Modified Version by various +parties---for example, statements of peer review or that the text has +been approved by an organization as the authoritative definition of a +standard. -@item Click on "Continue" until the certificate is created +You may add a passage of up to five words as a Front-Cover Text, and a +passage of up to 25 words as a Back-Cover Text, to the end of the list +of Cover Texts in the Modified Version. Only one passage of +Front-Cover Text and one of Back-Cover Text may be added by (or +through arrangements made by) any one entity. If the Document already +includes a cover text for the same cover, previously added by you or +by arrangement made by the same entity you are acting on behalf of, +you may not add another; but you may replace the old one, on explicit +permission from the previous publisher that added the old one. + +The author(s) and publisher(s) of the Document do not by this License +give permission to use their names for publicity for or to assert or +imply endorsement of any Modified Version. + +@strong{5. COMBINING DOCUMENTS} + +You may combine the Document with other documents released under this +License, under the terms defined in section 4 above for modified +versions, provided that you include in the combination all of the +Invariant Sections of all of the original documents, unmodified, and +list them all as Invariant Sections of your combined work in its +license notice, and that you preserve all their Warranty Disclaimers. + +The combined work need only contain one copy of this License, and +multiple identical Invariant Sections may be replaced with a single +copy. If there are multiple Invariant Sections with the same name but +different contents, make the title of each such section unique by +adding at the end of it, in parentheses, the name of the original +author or publisher of that section if known, or else a unique number. +Make the same adjustment to the section titles in the list of +Invariant Sections in the license notice of the combined work. + +In the combination, you must combine any sections Entitled "History" +in the various original documents, forming one section Entitled +"History"; likewise combine any sections Entitled "Acknowledgements", +and any sections Entitled "Dedications". You must delete all sections +Entitled "Endorsements". + +@strong{6. COLLECTIONS OF DOCUMENTS} + +You may make a collection consisting of the Document and other documents +released under this License, and replace the individual copies of this +License in the various documents with a single copy that is included in +the collection, provided that you follow the rules of this License for +verbatim copying of each of the documents in all other respects. + +You may extract a single document from such a collection, and distribute +it individually under this License, provided you insert a copy of this +License into the extracted document, and follow this License in all +other respects regarding verbatim copying of that document. + +@strong{7. 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Any attempt +otherwise to copy, modify, sublicense, or distribute it is void, and +will automatically terminate your rights under this License. + +However, if you cease all violation of this License, then your license +from a particular copyright holder is reinstated (a) provisionally, +unless and until the copyright holder explicitly and finally +terminates your license, and (b) permanently, if the copyright holder +fails to notify you of the violation by some reasonable means prior to +60 days after the cessation. + +Moreover, your license from a particular copyright holder is +reinstated permanently if the copyright holder notifies you of the +violation by some reasonable means, this is the first time you have +received notice of violation of this License (for any work) from that +copyright holder, and you cure the violation prior to 30 days after +your receipt of the notice. + +Termination of your rights under this section does not terminate the +licenses of parties who have received copies or rights from you under +this License. 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Texts." line with this: -Once a certificate has been created, the debugger can be codesigned -as follow. In a Terminal, run the following command... +@quotation -@smallexample -codesign -f -s "gdb-cert" <gnat_install_prefix>/bin/gdb -@end smallexample +with the Invariant Sections being LIST THEIR TITLES, with the +Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. +@end quotation -... where "gdb-cert" should be replaced by the actual certificate -name chosen above, and <gnat_install_prefix> should be replaced by -the location where you installed GNAT. Also, be sure that users are -in the Unix group @samp{_developer}. +If you have Invariant Sections without Cover Texts, or some other +combination of the three, merge those two alternatives to suit the +situation. -@c ********************************** -@c * GNU Free Documentation License * -@c ********************************** -@include fdl.texi -@c GNU Free Documentation License +If your document contains nontrivial examples of program code, we +recommend releasing these examples in parallel under your choice of +free software license, such as the GNU General Public License, +to permit their use in free software. -@node Index +@node Index,,GNU Free Documentation License,Top @unnumbered Index -@printindex cp -@contents -@c Put table of contents at end, otherwise it precedes the "title page" in -@c the .txt version -@c Edit the pdf file to move the contents to the beginning, after the title -@c page +@printindex ge + +@c %**end of body @bye |