1# ===========================================================================
2#    http://www.nongnu.org/autoconf-archive/ax_gcc_warn_unused_result.html
3# ===========================================================================
4#
5# SYNOPSIS
6#
7#   AX_GCC_WARN_UNUSED_RESULT
8#
9# DESCRIPTION
10#
11#   The macro will compile a test program to see whether the compiler does
12#   understand the per-function postfix pragma.
13#
14# LICENSE
15#
16#   Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
17#
18#   This program is free software; you can redistribute it and/or modify it
19#   under the terms of the GNU General Public License as published by the
20#   Free Software Foundation; either version 2 of the License, or (at your
21#   option) any later version.
22#
23#   This program is distributed in the hope that it will be useful, but
24#   WITHOUT ANY WARRANTY; without even the implied warranty of
25#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
26#   Public License for more details.
27#
28#   You should have received a copy of the GNU General Public License along
29#   with this program. If not, see <http://www.gnu.org/licenses/>.
30#
31#   As a special exception, the respective Autoconf Macro's copyright owner
32#   gives unlimited permission to copy, distribute and modify the configure
33#   scripts that are the output of Autoconf when processing the Macro. You
34#   need not follow the terms of the GNU General Public License when using
35#   or distributing such scripts, even though portions of the text of the
36#   Macro appear in them. The GNU General Public License (GPL) does govern
37#   all other use of the material that constitutes the Autoconf Macro.
38#
39#   This special exception to the GPL applies to versions of the Autoconf
40#   Macro released by the Autoconf Archive. When you make and distribute a
41#   modified version of the Autoconf Macro, you may extend this special
42#   exception to the GPL to apply to your modified version as well.
43
44AC_DEFUN([AX_GCC_WARN_UNUSED_RESULT],[dnl
45AC_CACHE_CHECK(
46 [whether the compiler supports function __attribute__((__warn_unused_result__))],
47 ax_cv_gcc_warn_unused_result,[
48 AC_TRY_COMPILE([__attribute__((__warn_unused_result__))
49 int f(int i) { return i; }],
50 [],
51 ax_cv_gcc_warn_unused_result=yes, ax_cv_gcc_warn_unused_result=no)])
52 if test "$ax_cv_gcc_warn_unused_result" = yes; then
53   AC_DEFINE([GCC_WARN_UNUSED_RESULT],[__attribute__((__warn_unused_result__))],
54    [most gcc compilers know a function __attribute__((__warn_unused_result__))])
55 fi
56])
57