mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-12-11 09:20:51 +00:00
63 lines
2.5 KiB
C
63 lines
2.5 KiB
C
/* ignore a function return without a compiler warning
|
|
|
|
Copyright (C) 2008-2011 Free Software Foundation, Inc.
|
|
|
|
This program is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>. */
|
|
|
|
/* Written by Jim Meyering, Eric Blake and Pádraig Brady. */
|
|
|
|
/* Use "ignore_value" to avoid a warning when using a function declared with
|
|
gcc's warn_unused_result attribute, but for which you really do want to
|
|
ignore the result. Traditionally, people have used a "(void)" cast to
|
|
indicate that a function's return value is deliberately unused. However,
|
|
if the function is declared with __attribute__((warn_unused_result)),
|
|
gcc issues a warning even with the cast.
|
|
|
|
Caution: most of the time, you really should heed gcc's warning, and
|
|
check the return value. However, in those exceptional cases in which
|
|
you're sure you know what you're doing, use this function.
|
|
|
|
For the record, here's one of the ignorable warnings:
|
|
"copy.c:233: warning: ignoring return value of 'fchown',
|
|
declared with attribute warn_unused_result". */
|
|
|
|
#ifndef _GL_IGNORE_VALUE_H
|
|
# define _GL_IGNORE_VALUE_H
|
|
|
|
# ifndef ATTRIBUTE_DEPRECATED
|
|
/* The __attribute__((__deprecated__)) feature
|
|
is available in gcc versions 3.1 and newer. */
|
|
# if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 1)
|
|
# define ATTRIBUTE_DEPRECATED /* empty */
|
|
# else
|
|
# define ATTRIBUTE_DEPRECATED __attribute__ ((__deprecated__))
|
|
# endif
|
|
# endif
|
|
|
|
/* The __attribute__((__warn_unused_result__)) feature
|
|
is available in gcc versions 3.4 and newer,
|
|
while the typeof feature has been available since 2.7 at least. */
|
|
# if __GNUC__ < 3 || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
|
|
# define ignore_value(x) ((void) (x))
|
|
# else
|
|
# define ignore_value(x) (({ __typeof__ (x) __x = (x); (void) __x; }))
|
|
# endif
|
|
|
|
/* ignore_value works for scalars, pointers and aggregates;
|
|
deprecate ignore_ptr. */
|
|
static inline void ATTRIBUTE_DEPRECATED
|
|
ignore_ptr (void *p) { (void) p; } /* deprecated: use ignore_value */
|
|
|
|
#endif
|