dnl Copyright (C) 2004-2008 Kim Woelders dnl Copyright (C) 2008 Vincent Torri <vtorri at univ-evry dot fr> dnl That code is public domain and can be freely used or copied. dnl Originally snatched from somewhere... dnl Macro for checking if the compiler supports __attribute__ dnl Usage: AC_C___ATTRIBUTE__ dnl call AC_DEFINE for HAVE___ATTRIBUTE__ and __UNUSED__ dnl if the compiler supports __attribute__, HAVE___ATTRIBUTE__ is dnl defined to 1 and __UNUSED__ is defined to __attribute__((unused)) dnl otherwise, HAVE___ATTRIBUTE__ is not defined and __UNUSED__ is dnl defined to nothing. AC_DEFUN([AC_C___ATTRIBUTE__], [ AC_MSG_CHECKING([for __attribute__]) AC_CACHE_VAL([ac_cv___attribute__], [AC_TRY_COMPILE( [ #include <stdlib.h> int func(int x); int foo(int x __attribute__ ((unused))) { exit(1); } ], [], [ac_cv___attribute__="yes"], [ac_cv___attribute__="no"] )]) AC_MSG_RESULT($ac_cv___attribute__) if test "x${ac_cv___attribute__}" = "xyes" ; then AC_DEFINE([HAVE___ATTRIBUTE__], [1], [Define to 1 if your compiler has __attribute__]) AC_DEFINE([__UNUSED__], [__attribute__((unused))], [Macro declaring a function argument to be unused]) else AC_DEFINE([__UNUSED__], [], [Macro declaring a function argument to be unused]) fi ]) dnl End of ac_attribute.m4