From fb52f6de351c5a0393d0fb81bff14538525b0493 Mon Sep 17 00:00:00 2001 From: Jason Merrill Date: Thu, 21 Aug 1997 20:30:16 -0400 Subject: release notes From-SVN: r14883 --- gcc/cp/NEWS | 139 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 139 insertions(+) create mode 100644 gcc/cp/NEWS (limited to 'gcc/cp/NEWS') diff --git a/gcc/cp/NEWS b/gcc/cp/NEWS new file mode 100644 index 0000000..8f057ef --- /dev/null +++ b/gcc/cp/NEWS @@ -0,0 +1,139 @@ +*** Changes since G++ version 2.7.2: + +* A public review copy of the December 1996 Draft of the ANSI C++ + proto-standard is now available. See + + http://www.cygnus.com/misc/wp/ + + for more information. + +* Default function arguments in templates will not be evaluated (or + checked for semantic validity) unless they are needed. + +* The -ftemplate-depth-NN flag can be used to increase the maximum + recursive template instantiation depth, defaulting to 17. If you need + to use this flag, the compiler will tell you. + +* The internal interface between RTTI-using code and the RTTI support + library has changed, so code that uses dynamic_cast should be + recompiled. The RTTI support library has moved from libstdc++ to + libgcc, so you no longer need to link against libstdc++ for a program + that doesn't use the "hosted" library. + +* bool is now always the same size as another built-in type. Previously, + a 64-bit RISC target using a 32-bit ABI would have 32-bit pointers and a + 64-bit bool. This should only affect Irix 6, which was not supported in + 2.7.2. + +* new (nothrow) is now supported. + +* A flag -Weffc++ has been added for violations of some of the style + guidelines in Scott Meyers' _Effective C++_ books. + +* On ELF systems, duplicate copies of symbols with 'initialized common' + linkage (such as template instantiations, vtables, and extern inlines) + will now be discarded by the GNU linker, so you don't need to use -frepo. + This support requires GNU ld from binutils 2.8 or later. + +* Partial specialization of class templates is now supported. + +* The overload resolution code has been rewritten to conform to the latest + C++ Working Paper. Built-in operators are now considered as candidates + in operator overload resolution. Function template overloading chooses + the more specialized template, and handles base classes in type deduction + and guiding declarations properly. In this release the old code can + still be selected with -fno-ansi-overloading, although this is not + supported and will be removed in a future release. + +* RTTI support has been rewritten to work properly and is now on by default. + This means code that uses virtual functions will have a modest space + overhead. You can use the -fno-rtti flag to disable RTTI support. + +* Synthesized destructors are no longer made virtual just because the class + already has virtual functions, only if they override a virtual destructor + in a base class. The compiler will warn if this affects your code. + +* The g++ driver no longer links with libg++ by default; it is now + functionally identical to the c++ driver. + +* (void *)0 is no longer considered a null pointer constant; NULL in + is now defined as __null, a magic constant of type (void *) + normally, or (size_t) with -ansi. + +* The new 'template <>' specialization syntax is now accepted and ignored. + +* The name of a class is now implicitly declared in its own scope; A::A + refers to A. + +* g++ now uses a new implementation of templates. The basic idea is that + now templates are minimally parsed when seen and then expanded later. + This allows conformant early name binding and instantiation controls, + since instantiations no longer have to go through the parser. + + What you get: + + + Inlining of template functions works without any extra effort or + modifications. + + Instantiations of class templates and methods defined in the class + body are deferred until they are actually needed (unless + -fexternal-templates is specified). + + Nested types in class templates work. + + Static data member templates work. + + Possible problems: + + + Types and class templates used in templates must be declared + first, or the compiler will assume they are not types, and fail. + + Similarly, nested types of template type parameters must be tagged + with the 'typename' keyword. In many cases, the compiler will tell + you where you need to add 'typename'. + + Syntax errors in templates that are never instantiated will now be + diagnosed. + +* Synthesized methods are now emitted in any translation units that need + an out-of-line copy. They are no longer affected by #pragma interface + or #pragma implementation. + +* Local classes are now supported. + +* -Wall no longer implies -W. + The new warning flag, -Wsign-compare, included in -Wall, warns about + dangerous comparisons of signed and unsigned values. Only the flag is + new; it was previously part of -W. + +* The new flag, -fno-weak, disables the use of weak symbols. + +* __attribute__ can now be attached to types as well as declarations. + +* -Woverloaded-virtual now warns if a virtual function in a base class is + hidden in a derived class, rather than warning about virtual functions + being overloaded (even if all of the inherited signatures are + overridden) as it did before. + +* The compiler no longer emits a warning if an ellipsis is used as a + function's argument list. + +* Exception handling support has been significantly improved and is on by + default. This can result in significant runtime overhead. You can turn + it off with -fno-exceptions. + +* Definition of nested types outside of their containing class is now + supported. Use the following source code, as an example. + + struct A { + struct B; + B* bp; + }; + + struct A::B { + int member; + }; + +* Explicit instantiation of template constructors and destructors is now + supported. Use the following source code, as an example. + + template A::A(const A&); + +* On the HPPA, some classes that do not define a copy constructor + will be passed and returned in memory again so that functions + returning those types can be inlined. -- cgit v1.1