1 dnl Macros to check the presence of generic (non-typed) symbols.
2 dnl Copyright (c) 2006-2007 Diego Pettenò <flameeyes@gmail.com>
3 dnl Copyright (c) 2006-2007 xine project
5 dnl This program is free software; you can redistribute it and/or modify
6 dnl it under the terms of the GNU General Public License as published by
7 dnl the Free Software Foundation; either version 2, or (at your option)
10 dnl This program is distributed in the hope that it will be useful,
11 dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
12 dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 dnl GNU General Public License for more details.
15 dnl You should have received a copy of the GNU General Public License
16 dnl along with this program; if not, write to the Free Software
17 dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 dnl As a special exception, the copyright owners of the
21 dnl macro gives unlimited permission to copy, distribute and modify the
22 dnl configure scripts that are the output of Autoconf when processing the
23 dnl Macro. You need not follow the terms of the GNU General Public
24 dnl License when using or distributing such scripts, even though portions
25 dnl of the text of the Macro appear in them. The GNU General Public
26 dnl License (GPL) does govern all other use of the material that
27 dnl constitutes the Autoconf Macro.
29 dnl This special exception to the GPL applies to versions of the
30 dnl Autoconf Macro released by this project. When you make and
31 dnl distribute a modified version of the Autoconf Macro, you may extend
32 dnl this special exception to the GPL to apply to your modified version as
35 AC_DEFUN([CC_CHECK_CFLAGS_SILENT], [
36 AC_CACHE_VAL(AS_TR_SH([cc_cv_cflags_$1]),
37 [ac_save_CFLAGS="$CFLAGS"
39 AC_COMPILE_IFELSE([int a;],
40 [eval "AS_TR_SH([cc_cv_cflags_$1])='yes'"],
41 [eval "AS_TR_SH([cc_cv_cflags_$1])='no'"])
42 CFLAGS="$ac_save_CFLAGS"
45 AS_IF([eval test x$]AS_TR_SH([cc_cv_cflags_$1])[ = xyes],
49 AC_DEFUN([CC_CHECK_CFLAGS], [
50 AC_CACHE_CHECK([if $CC supports $1 flag],
51 AS_TR_SH([cc_cv_cflags_$1]),
52 CC_CHECK_CFLAGS_SILENT([$1]) dnl Don't execute actions here!
55 AS_IF([eval test x$]AS_TR_SH([cc_cv_cflags_$1])[ = xyes],
59 AC_DEFUN([CC_CHECK_LDFLAGS], [
60 AC_CACHE_CHECK([if $CC supports $1 flag],
61 AS_TR_SH([cc_cv_ldflags_$1]),
62 [ac_save_LDFLAGS="$LDFLAGS"
64 AC_LINK_IFELSE([int main() { return 1; }],
65 [eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"],
66 [eval "AS_TR_SH([cc_cv_ldflags_$1])="])
67 LDFLAGS="$ac_save_LDFLAGS"
70 AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
74 dnl Check for a -Werror flag or equivalent. -Werror is the GCC
75 dnl and ICC flag that tells the compiler to treat all the warnings
76 dnl as fatal. We usually need this option to make sure that some
77 dnl constructs (like attributes) are not simply ignored.
79 dnl Other compilers don't support -Werror per se, but they support
80 dnl an equivalent flag:
81 dnl - Sun Studio compiler supports -errwarn=%all
82 AC_DEFUN([CC_CHECK_WERROR], [
84 [for $CC way to treat warnings as errors],
86 [CC_CHECK_CFLAGS_SILENT([-Werror], [cc_cv_werror=-Werror],
87 [CC_CHECK_CFLAGS_SILENT([-errwarn=%all], [cc_cv_werror=-errwarn=%all])])
91 AC_DEFUN([CC_CHECK_ATTRIBUTE], [
92 AC_REQUIRE([CC_CHECK_WERROR])
93 AC_CACHE_CHECK([if $CC supports __attribute__(( ifelse([$2], , [$1], [$2]) ))],
94 AS_TR_SH([cc_cv_attribute_$1]),
95 [ac_save_CFLAGS="$CFLAGS"
96 CFLAGS="$CFLAGS $cc_cv_werror"
97 AC_COMPILE_IFELSE([$3],
98 [eval "AS_TR_SH([cc_cv_attribute_$1])='yes'"],
99 [eval "AS_TR_SH([cc_cv_attribute_$1])='no'"])
100 CFLAGS="$ac_save_CFLAGS"
103 AS_IF([eval test x$]AS_TR_SH([cc_cv_attribute_$1])[ = xyes],
105 AS_TR_CPP([SUPPORT_ATTRIBUTE_$1]), 1,
106 [Define this if the compiler supports __attribute__(( ifelse([$2], , [$1], [$2]) ))]
112 AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
115 [void __attribute__((constructor)) ctor() { int a; }],
119 AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
121 [format], [format(printf, n, n)],
122 [void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { fmt = (void *)0; }],
126 AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
128 [format_arg], [format_arg(printf)],
129 [char *__attribute__((format_arg(1))) gettextlike(const char *fmt) { fmt = (void *)0; }],
133 AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
135 [visibility_$1], [visibility("$1")],
136 [void __attribute__((visibility("$1"))) $1_function() { }],
140 AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
142 [nonnull], [nonnull()],
143 [void __attribute__((nonnull())) some_function(void *foo, void *bar) { foo = (void*)0; bar = (void*)0; }],
147 AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
150 [void some_function(void *foo, __attribute__((unused)) void *bar);],
154 AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
157 [void some_function(void *foo, ...) __attribute__((sentinel));],
161 AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [
164 [void some_function(void *foo, ...) __attribute__((deprecated));],
168 AC_DEFUN([CC_ATTRIBUTE_ALIAS], [
170 [alias], [weak, alias],
171 [void other_function(void *foo) { }
172 void some_function(void *foo) __attribute__((weak, alias("other_function")));],
176 AC_DEFUN([CC_ATTRIBUTE_MALLOC], [
179 [void * __attribute__((malloc)) my_alloc(int n);],
183 AC_DEFUN([CC_ATTRIBUTE_PACKED], [
186 [struct astructure { char a; int b; long c; void *d; } __attribute__((packed));],
190 AC_DEFUN([CC_ATTRIBUTE_CONST], [
193 [int __attribute__((const)) twopow(int n) { return 1 << n; } ],
197 AC_DEFUN([CC_FLAG_VISIBILITY], [
198 AC_REQUIRE([CC_CHECK_WERROR])
199 AC_CACHE_CHECK([if $CC supports -fvisibility=hidden],
200 [cc_cv_flag_visibility],
201 [cc_flag_visibility_save_CFLAGS="$CFLAGS"
202 CFLAGS="$CFLAGS $cc_cv_werror"
203 CC_CHECK_CFLAGS_SILENT([-fvisibility=hidden],
204 cc_cv_flag_visibility='yes',
205 cc_cv_flag_visibility='no')
206 CFLAGS="$cc_flag_visibility_save_CFLAGS"])
208 AS_IF([test "x$cc_cv_flag_visibility" = "xyes"],
209 [AC_DEFINE([SUPPORT_FLAG_VISIBILITY], 1,
210 [Define this if the compiler supports the -fvisibility flag])
215 AC_DEFUN([CC_FUNC_EXPECT], [
216 AC_REQUIRE([CC_CHECK_WERROR])
217 AC_CACHE_CHECK([if compiler has __builtin_expect function],
219 [ac_save_CFLAGS="$CFLAGS"
220 CFLAGS="$CFLAGS $cc_cv_werror"
222 [int some_function() {
224 return (int)__builtin_expect(a, 3);
226 [cc_cv_func_expect=yes],
227 [cc_cv_func_expect=no])
228 CFLAGS="$ac_save_CFLAGS"
231 AS_IF([test "x$cc_cv_func_expect" = "xyes"],
232 [AC_DEFINE([SUPPORT__BUILTIN_EXPECT], 1,
233 [Define this if the compiler supports __builtin_expect() function])
238 AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [
239 AC_REQUIRE([CC_CHECK_WERROR])
240 AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported],
241 [cc_cv_attribute_aligned],
242 [ac_save_CFLAGS="$CFLAGS"
243 CFLAGS="$CFLAGS $cc_cv_werror"
244 for cc_attribute_align_try in 64 32 16 8 4 2; do
247 static char c __attribute__ ((aligned($cc_attribute_align_try))) = 0;
249 }], [cc_cv_attribute_aligned=$cc_attribute_align_try; break])
251 CFLAGS="$ac_save_CFLAGS"
254 if test "x$cc_cv_attribute_aligned" != "x"; then
255 AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX], [$cc_cv_attribute_aligned],
256 [Define the highest alignment supported])