From: Paul Eggert <eggert@cs.ucla.edu>
Date: Thu, 3 Feb 2011 21:38:34 +0000 (-0800)
Subject: * lib/ignore-value.h: New file.
X-Git-Tag: emacs-pretest-24.0.90~104^2~275^2~1048
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=5dc7a1d2c412fc485cca66a2be76f50bfa1f16d7;p=emacs.git

* lib/ignore-value.h: New file.
---

5dc7a1d2c412fc485cca66a2be76f50bfa1f16d7
diff --cc ChangeLog
index 7b693be0694,7b693be0694..df1d6bc2144
--- a/ChangeLog
+++ b/ChangeLog
@@@ -3,6 -3,6 +3,7 @@@
  	allow C code to suppress warnings about ignored return values
  	* Makefile.in (GNULIB_MODULES): Add ignore-value.
  	* configure, lib/Makefile.in, lib/gnulib.mk, m4/gl-comp.m4: Regenerate.
++	* lib/ignore-value.h: New file.
  
  2011-01-31  Chong Yidong  <cyd@stupidchicken.com>
  
diff --cc lib/ignore-value.h
index 00000000000,00000000000..5e683bbb533
new file mode 100644
--- /dev/null
+++ b/lib/ignore-value.h
@@@ -1,0 -1,0 +1,62 @@@
++/* 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