lfstack: implement test
[urcu.git] / config / ax_tls.m4
1 # ===========================================================================
2 # http://www.gnu.org/software/autoconf-archive/ax_tls.html
3 # ===========================================================================
4 #
5 # SYNOPSIS
6 #
7 # AX_TLS([action-if-found], [action-if-not-found])
8 #
9 # DESCRIPTION
10 #
11 # Provides a test for the compiler support of thread local storage (TLS)
12 # extensions. Defines TLS if it is found. Currently knows about GCC/ICC
13 # and MSVC. I think SunPro uses the same as GCC, and Borland apparently
14 # supports either.
15 #
16 # LICENSE
17 #
18 # Copyright (c) 2008 Alan Woodland <ajw05@aber.ac.uk>
19 # Copyright (c) 2010 Diego Elio Petteno` <flameeyes@gmail.com>
20 #
21 # This program is free software: you can redistribute it and/or modify it
22 # under the terms of the GNU General Public License as published by the
23 # Free Software Foundation, either version 3 of the License, or (at your
24 # option) any later version.
25 #
26 # This program is distributed in the hope that it will be useful, but
27 # WITHOUT ANY WARRANTY; without even the implied warranty of
28 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
29 # Public License for more details.
30 #
31 # You should have received a copy of the GNU General Public License along
32 # with this program. If not, see <http://www.gnu.org/licenses/>.
33 #
34 # As a special exception, the respective Autoconf Macro's copyright owner
35 # gives unlimited permission to copy, distribute and modify the configure
36 # scripts that are the output of Autoconf when processing the Macro. You
37 # need not follow the terms of the GNU General Public License when using
38 # or distributing such scripts, even though portions of the text of the
39 # Macro appear in them. The GNU General Public License (GPL) does govern
40 # all other use of the material that constitutes the Autoconf Macro.
41 #
42 # This special exception to the GPL applies to versions of the Autoconf
43 # Macro released by the Autoconf Archive. When you make and distribute a
44 # modified version of the Autoconf Macro, you may extend this special
45 # exception to the GPL to apply to your modified version as well.
46
47 #serial 11
48
49 # Define m4_ifblank and m4_ifnblank macros from introduced in
50 # autotools 2.64 m4sugar.m4 if using an earlier autotools.
51
52 ifdef([m4_ifblank], [], [
53 m4_define([m4_ifblank],
54 [m4_if(m4_translit([[$1]], [ ][ ][
55 ]), [], [$2], [$3])])
56 ])
57
58
59 ifdef([m4_ifnblank], [], [
60 m4_define([m4_ifnblank],
61 [m4_if(m4_translit([[$1]], [ ][ ][
62 ]), [], [$3], [$2])])
63 ])
64
65 AC_DEFUN([AX_TLS], [
66 AC_MSG_CHECKING(for thread local storage (TLS) class)
67 AC_CACHE_VAL(ac_cv_tls, [
68 ax_tls_keywords="__thread __declspec(thread) none"
69 for ax_tls_keyword in $ax_tls_keywords; do
70 AS_CASE([$ax_tls_keyword],
71 [none], [ac_cv_tls=none ; break],
72 [AC_TRY_COMPILE(
73 [#include <stdlib.h>
74 static void
75 foo(void) {
76 static ] $ax_tls_keyword [ int bar;
77 exit(1);
78 }],
79 [],
80 [ac_cv_tls=$ax_tls_keyword ; break],
81 ac_cv_tls=none
82 )])
83 done
84 ])
85 AC_MSG_RESULT($ac_cv_tls)
86
87 AS_IF([test "$ac_cv_tls" != "none"],
88 AC_DEFINE_UNQUOTED([TLS], $ac_cv_tls, [If the compiler supports a TLS storage class define it to that here])
89 m4_ifnblank([$1], [$1]),
90 m4_ifnblank([$2], [$2])
91 )
92 ])
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