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