/* ignore a function return without a compiler warning.  -*- coding: utf-8 -*-

   Copyright (C) 2008-2017 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

/* Normally casting an expression to void discards its value, but GCC

   versions 3.4 and newer have __attribute__ ((__warn_unused_result__))

   which may cause unwanted diagnostics in that case.  Use __typeof__

   and __extension__ to work around the problem, if the workaround is

   known to be needed.  */

#if 3 < __GNUC__ + (4 <= __GNUC_MINOR__)

# define ignore_value(x) \

    (__extension__ ({ __typeof__ (x) __x = (x); (void) __x; }))

#else

# define ignore_value(x) ((void) (x))

#endif

#endif