1# =========================================================================== 2# https://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 <https://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 9 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