diff options
| -rw-r--r-- | gdb/doc/ChangeLog | 7 | ||||
| -rw-r--r-- | gdb/doc/gdb.texinfo | 72 |
2 files changed, 65 insertions, 14 deletions
diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index b636a95..ea27a62 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,10 @@ +2011-07-26 Jan Kratochvil <jan.kratochvil@redhat.com> + Eli Zaretskii <eliz@gnu.org> + + * gdb.texinfo (whatis, ptype): Highlight their differences. Describe + typedefs unrolling. Extend the sample code by an inner typedef and + outer typedefs unrolling. + 2011-07-26 Paul Pluzhnikov <ppluzhnikov@google.com> * gdb.texinfo (Caching Remote Data): Document {set,show} dcache diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index b5cfc7d..600ad72 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -13895,16 +13895,34 @@ __read_nocancel + 6 in section .text of /usr/lib64/libc.so.6 @kindex whatis @item whatis [@var{arg}] -Print the data type of @var{arg}, which can be either an expression or -a data type. With no argument, print the data type of @code{$}, the -last value in the value history. If @var{arg} is an expression, it is -not actually evaluated, and any side-effecting operations (such as -assignments or function calls) inside it do not take place. If -@var{arg} is a type name, it may be the name of a type or typedef, or -for C code it may have the form @samp{class @var{class-name}}, -@samp{struct @var{struct-tag}}, @samp{union @var{union-tag}} or -@samp{enum @var{enum-tag}}. -@xref{Expressions, ,Expressions}. +Print the data type of @var{arg}, which can be either an expression +or a name of a data type. With no argument, print the data type of +@code{$}, the last value in the value history. + +If @var{arg} is an expression (@pxref{Expressions, ,Expressions}), it +is not actually evaluated, and any side-effecting operations (such as +assignments or function calls) inside it do not take place. + +If @var{arg} is a variable or an expression, @code{whatis} prints its +literal type as it is used in the source code. If the type was +defined using a @code{typedef}, @code{whatis} will @emph{not} print +the data type underlying the @code{typedef}. If the type of the +variable or the expression is a compound data type, such as +@code{struct} or @code{class}, @code{whatis} never prints their +fields or methods. It just prints the @code{struct}/@code{class} +name (a.k.a.@: its @dfn{tag}). If you want to see the members of +such a compound data type, use @code{ptype}. + +If @var{arg} is a type name that was defined using @code{typedef}, +@code{whatis} @dfn{unrolls} only one level of that @code{typedef}. +Unrolling means that @code{whatis} will show the underlying type used +in the @code{typedef} declaration of @var{arg}. However, if that +underlying type is also a @code{typedef}, @code{whatis} will not +unroll it. + +For C code, the type names may also have the form @samp{class +@var{class-name}}, @samp{struct @var{struct-tag}}, @samp{union +@var{union-tag}} or @samp{enum @var{enum-tag}}. @kindex ptype @item ptype [@var{arg}] @@ -13912,10 +13930,23 @@ for C code it may have the form @samp{class @var{class-name}}, detailed description of the type, instead of just the name of the type. @xref{Expressions, ,Expressions}. +Contrary to @code{whatis}, @code{ptype} always unrolls any +@code{typedef}s in its argument declaration, whether the argument is +a variable, expression, or a data type. This means that @code{ptype} +of a variable or an expression will not print literally its type as +present in the source code---use @code{whatis} for that. @code{typedef}s at +the pointer or reference targets are also unrolled. Only @code{typedef}s of +fields, methods and inner @code{class typedef}s of @code{struct}s, +@code{class}es and @code{union}s are not unrolled even with @code{ptype}. + For example, for this variable declaration: @smallexample -struct complex @{double real; double imag;@} v; +typedef double real_t; +struct complex @{ real_t real; double imag; @}; +typedef struct complex complex_t; +complex_t var; +real_t *real_pointer_var; @end smallexample @noindent @@ -13923,13 +13954,26 @@ the two commands give this output: @smallexample @group -(@value{GDBP}) whatis v +(@value{GDBP}) whatis var +type = complex_t +(@value{GDBP}) ptype var +type = struct complex @{ + real_t real; + double imag; +@} +(@value{GDBP}) whatis complex_t +type = struct complex +(@value{GDBP}) whatis struct complex type = struct complex -(@value{GDBP}) ptype v +(@value{GDBP}) ptype struct complex type = struct complex @{ - double real; + real_t real; double imag; @} +(@value{GDBP}) whatis real_pointer_var +type = real_t * +(@value{GDBP}) ptype real_pointer_var +type = double * @end group @end smallexample |