uatomic/x86: Remove redundant memory barriers
[urcu.git] / m4 / ax_check_compile_flag.m4
CommitLineData
d001c886 1# SPDX-License-Identifier: FSFAP
ee334e48
MJ
2# ===========================================================================
3# https://www.gnu.org/software/autoconf-archive/ax_check_compile_flag.html
4# ===========================================================================
5#
6# SYNOPSIS
7#
8# AX_CHECK_COMPILE_FLAG(FLAG, [ACTION-SUCCESS], [ACTION-FAILURE], [EXTRA-FLAGS], [INPUT])
9#
10# DESCRIPTION
11#
12# Check whether the given FLAG works with the current language's compiler
13# or gives an error. (Warnings, however, are ignored)
14#
15# ACTION-SUCCESS/ACTION-FAILURE are shell commands to execute on
16# success/failure.
17#
18# If EXTRA-FLAGS is defined, it is added to the current language's default
19# flags (e.g. CFLAGS) when the check is done. The check is thus made with
20# the flags: "CFLAGS EXTRA-FLAGS FLAG". This can for example be used to
21# force the compiler to issue an error when a bad flag is given.
22#
23# INPUT gives an alternative input source to AC_COMPILE_IFELSE.
24#
25# NOTE: Implementation based on AX_CFLAGS_GCC_OPTION. Please keep this
26# macro in sync with AX_CHECK_{PREPROC,LINK}_FLAG.
27#
28# LICENSE
29#
30# Copyright (c) 2008 Guido U. Draheim <guidod@gmx.de>
31# Copyright (c) 2011 Maarten Bosmans <mkbosmans@gmail.com>
32#
33# Copying and distribution of this file, with or without modification, are
34# permitted in any medium without royalty provided the copyright notice
35# and this notice are preserved. This file is offered as-is, without any
36# warranty.
37
38#serial 6
39
40AC_DEFUN([AX_CHECK_COMPILE_FLAG],
41[AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
42AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1])dnl
43AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [
44 ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS
45 _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1"
46 AC_COMPILE_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],
47 [AS_VAR_SET(CACHEVAR,[yes])],
48 [AS_VAR_SET(CACHEVAR,[no])])
49 _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags])
50AS_VAR_IF(CACHEVAR,yes,
51 [m4_default([$2], :)],
52 [m4_default([$3], :)])
53AS_VAR_POPDEF([CACHEVAR])dnl
54])dnl AX_CHECK_COMPILE_FLAGS
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