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ezstream/m4/attribute.m4
2015-04-16 19:30:36 +02:00

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dnl # $Id$
dnl # Check if the compiler understands a certain __attribute__.
dnl # Copyright (c) 2008 Moritz Grimm <mgrimm@mrsserver.net>
dnl #
dnl # Permission to use, copy, modify, and distribute this software for any
dnl # purpose with or without fee is hereby granted, provided that the above
dnl # copyright notice and this permission notice appear in all copies.
dnl #
dnl # THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
dnl # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
dnl # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
dnl # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
dnl # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
dnl # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
dnl # OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
dnl # AX_FUNC_ATTRIBUTE([FUNC-SIGNATURE], [ATTRIBUTE], [ARGS],
dnl # [ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
dnl # AX_FUNC_ATTRIBUTE_UNUSED([ACTION-IF-FOUND], [ACTION-IF-NOT-FOUND])
AC_DEFUN([AX_FUNC_ATTRIBUTE],
[
AC_REQUIRE([AX_CHECK_ERROR_FLAG])
if test x"${local_cv_prog_cc_error_flag}" != "xno"; then
_errflag="${local_cv_prog_cc_error_flag}"
else
_errflag=""
fi
AC_MSG_CHECKING([if __attribute__((__$2__$3)) is supported])
_cv_sufx_=$(echo "$3" | sed 'y|-+,=() |_p_____|')
AC_CACHE_VAL([local_cv_prog_cc_attr_$2_${_cv_sufx}],
[
AC_LANG_PUSH([C])
save_CFLAGS="${CFLAGS}"
CFLAGS="${CFLAGS} ${_errflag}"
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#include <stdlib.h>
void * attrtest($1)
__attribute__((__$2__$3));
void *
attrtest($1) { return(NULL); }
]],
[[]])],
[eval "local_cv_prog_cc_attr_$2_${_cv_sufx_}=yes"],
[eval "local_cv_prog_cc_attr_$2_${_cv_sufx_}=no"])
CFLAGS="${save_CFLAGS}"
AC_LANG_POP([C])
])
eval "_cache_val_=\${local_cv_prog_cc_attr_$2_${_cv_sufx_}}"
if test x"${_cache_val_}" = "xyes"; then
AC_MSG_RESULT([yes])
:
$4
else
AC_MSG_RESULT([no])
:
$5
fi
])
AC_DEFUN([AX_FUNC_ATTRIBUTE_UNUSED],
[
AC_REQUIRE([AX_CHECK_ERROR_FLAG])
if test x"${local_cv_prog_cc_error_flag}" != "xno"; then
_errflag="${local_cv_prog_cc_error_flag}"
else
_errflag=""
fi
AC_MSG_CHECKING([if __attribute__((unused)) is supported])
AC_CACHE_VAL([local_cv_proc_cc_attr_unused],
[
AC_LANG_PUSH([C])
save_CFLAGS="${CFLAGS}"
CFLAGS="${CFLAGS} ${_errflag}"
AC_COMPILE_IFELSE(
[AC_LANG_PROGRAM(
[[
void attrtest(void)
__attribute__((unused));
void
attrtest(void) {}
]],
[[
int attrtest_var
__attribute__((unused));
]])],
[local_cv_proc_cc_attr_unused=yes],
[local_cv_proc_cc_attr_unused=no])
CFLAGS="${save_CFLAGS}"
AC_LANG_POP([C])
])
if test x"${local_cv_proc_cc_attr_unused}" = "xyes"; then
AC_MSG_RESULT([yes])
:
$1
else
AC_MSG_RESULT([no])
:
$2
fi
])