Mercurial > gnulib
view doc/posix-headers/stdnoreturn.texi @ 17364:7524d97ae56f
stdalign: port to stricter ISO C11
ISO C11 says that _Alignof's operand must be a parenthesized type.
Problem reported by Eli Zaretskii in
<http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00960.html>.
* doc/posix-headers/stdalign.texi (stdalign.h): Document this.
* m4/stdalign.m4 (gl_STDALIGN_H): Don't use _Alignof (expr).
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Fri, 29 Mar 2013 19:47:13 -0700 |
parents | bfb7633de5b0 |
children | 33db65a13e67 |
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@node stdnoreturn.h @section @file{stdnoreturn.h} POSIX specification:@* Not in POSIX yet, but we expect it will be. ISO C11 (latest free draft @url{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf}) sections 7.23. Gnulib module: stdnoreturn Portability problems fixed by Gnulib: @itemize @item This header file is missing on most circa-2012 platforms. @end itemize Portability problems not fixed by Gnulib: @itemize @item @code{<stdnoreturn.h>} should be #included before @samp{_Noreturn} is used. @item You cannot assume that @code{_Noreturn} is a reserved word; it might be a macro. @item On MSVC 9, @code{noreturn} expands to the empty token sequence, to avoid problems with standard headers that use @code{__declspec (noreturn)} directly. Although the resulting code operates correctly, the compiler is not informed whether @code{noreturn} functions do not return, so it may generate incorrect warnings at compile-time, or code that is slightly less optimized. This problem does not occur with @code{_Noreturn}. @item Circa 2012 bleeding-edge GCC with @code{-Werror=old-style-declaration} requires @code{_Noreturn} or @code{noreturn} before the returned type in a declaration, and therefore rejects valid but unusually-worded declarations such as @code{void _Noreturn foo (void);}. @end itemize