| @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 |
| When the macro @code{lint} is defined, standard headers define |
| @code{_Noreturn} (and therefore @code{noreturn}) to be a macro that |
| expands to the empty token sequence on some platforms: |
| Cygwin 2.5.1, FreeBSD 10.3. |
| @item |
| On Cygwin 1.7.30 and MSVC 14, @code{noreturn} expands to the empty token |
| sequence, to avoid problems with standard headers that use @code{noreturn} |
| in combination with @code{__attribute__} or @code{__declspec}. 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 |