1# ===========================================================================
2#    http://www.gnu.org/software/autoconf-archive/ax_c___attribute__.html
3# ===========================================================================
4#
5# SYNOPSIS
6#
7#   AX_C___ATTRIBUTE__
8#
9# DESCRIPTION
10#
11#   Provides a test for the compiler support of __attribute__ extensions.
12#   Defines HAVE___ATTRIBUTE__ if it is found.
13#
14# LICENSE
15#
16#   Copyright (c) 2008 Stepan Kasal <skasal@redhat.com>
17#   Copyright (c) 2008 Christian Haggstrom
18#   Copyright (c) 2008 Ryan McCabe <ryan@numb.org>
19#
20#   This program is free software; you can redistribute it and/or modify it
21#   under the terms of the GNU General Public License as published by the
22#   Free Software Foundation; either version 2 of the License, or (at your
23#   option) any later version.
24#
25#   This program is distributed in the hope that it will be useful, but
26#   WITHOUT ANY WARRANTY; without even the implied warranty of
27#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
28#   Public License for more details.
29#
30#   You should have received a copy of the GNU General Public License along
31#   with this program. If not, see <http://www.gnu.org/licenses/>.
32#
33#   As a special exception, the respective Autoconf Macro's copyright owner
34#   gives unlimited permission to copy, distribute and modify the configure
35#   scripts that are the output of Autoconf when processing the Macro. You
36#   need not follow the terms of the GNU General Public License when using
37#   or distributing such scripts, even though portions of the text of the
38#   Macro appear in them. The GNU General Public License (GPL) does govern
39#   all other use of the material that constitutes the Autoconf Macro.
40#
41#   This special exception to the GPL applies to versions of the Autoconf
42#   Macro released by the Autoconf Archive. When you make and distribute a
43#   modified version of the Autoconf Macro, you may extend this special
44#   exception to the GPL to apply to your modified version as well.
45
46#serial 8
47
48AC_DEFUN([AX_C___ATTRIBUTE__], [
49  AC_CACHE_CHECK([for __attribute__], [ax_cv___attribute__],
50    [AC_COMPILE_IFELSE(
51      [AC_LANG_PROGRAM(
52	[[#include <stdlib.h>
53	  static void foo(void) __attribute__ ((unused));
54	  static void
55	  foo(void) {
56	      exit(1);
57	  }
58        ]], [])],
59      [ax_cv___attribute__=yes],
60      [ax_cv___attribute__=no]
61    )
62  ])
63  if test "$ax_cv___attribute__" = "yes"; then
64    AC_DEFINE([HAVE___ATTRIBUTE__], 1, [define if your compiler has __attribute__])
65  fi
66])
67