1  # ===========================================================================
 2  #   http://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  #   This program is free software: you can redistribute it and/or modify it
33  #   under the terms of the GNU General Public License as published by the
34  #   Free Software Foundation, either version 3 of the License, or (at your
35  #   option) any later version.
36  #
37  #   This program is distributed in the hope that it will be useful, but
38  #   WITHOUT ANY WARRANTY; without even the implied warranty of
39  #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
40  #   Public License for more details.
41  #
42  #   You should have received a copy of the GNU General Public License along
43  #   with this program. If not, see <http://www.gnu.org/licenses/>.
44  #
45  #   As a special exception, the respective Autoconf Macro's copyright owner
46  #   gives unlimited permission to copy, distribute and modify the configure
47  #   scripts that are the output of Autoconf when processing the Macro. You
48  #   need not follow the terms of the GNU General Public License when using
49  #   or distributing such scripts, even though portions of the text of the
50  #   Macro appear in them. The GNU General Public License (GPL) does govern
51  #   all other use of the material that constitutes the Autoconf Macro.
52  #
53  #   This special exception to the GPL applies to versions of the Autoconf
54  #   Macro released by the Autoconf Archive. When you make and distribute a
55  #   modified version of the Autoconf Macro, you may extend this special
56  #   exception to the GPL to apply to your modified version as well.
57  
58  #serial 4
59  
60  AC_DEFUN([AX_CHECK_COMPILE_FLAG],
61  [AC_PREREQ(2.64)dnl for _AC_LANG_PREFIX and AS_VAR_IF
62  AS_VAR_PUSHDEF([CACHEVAR],[ax_cv_check_[]_AC_LANG_ABBREV[]flags_$4_$1])dnl
63  AC_CACHE_CHECK([whether _AC_LANG compiler accepts $1], CACHEVAR, [
64    ax_check_save_flags=$[]_AC_LANG_PREFIX[]FLAGS
65    _AC_LANG_PREFIX[]FLAGS="$[]_AC_LANG_PREFIX[]FLAGS $4 $1"
66    AC_COMPILE_IFELSE([m4_default([$5],[AC_LANG_PROGRAM()])],
67      [AS_VAR_SET(CACHEVAR,[yes])],
68      [AS_VAR_SET(CACHEVAR,[no])])
69    _AC_LANG_PREFIX[]FLAGS=$ax_check_save_flags])
70  AS_VAR_IF(CACHEVAR,yes,
71    [m4_default([$2], :)],
72    [m4_default([$3], :)])
73  AS_VAR_POPDEF([CACHEVAR])dnl
74  ])dnl AX_CHECK_COMPILE_FLAGS