1 dnl Macros to check the presence of generic (non-typed) symbols.
2 dnl Copyright (c) 2006-2008 Diego Pettenò <flameeyes@gmail.com>
3 dnl Copyright (c) 2006-2008 xine project
4 dnl Copyright (c) 2012 Lucas De Marchi <lucas.de.marchi@gmail.com>
6 dnl This program is free software; you can redistribute it and/or modify
7 dnl it under the terms of the GNU General Public License as published by
8 dnl the Free Software Foundation; either version 2, or (at your option)
11 dnl This program is distributed in the hope that it will be useful,
12 dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
13 dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 dnl GNU General Public License for more details.
16 dnl You should have received a copy of the GNU General Public License
17 dnl along with this program; if not, write to the Free Software
18 dnl Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
21 dnl As a special exception, the copyright owners of the
22 dnl macro gives unlimited permission to copy, distribute and modify the
23 dnl configure scripts that are the output of Autoconf when processing the
24 dnl Macro. You need not follow the terms of the GNU General Public
25 dnl License when using or distributing such scripts, even though portions
26 dnl of the text of the Macro appear in them. The GNU General Public
27 dnl License (GPL) does govern all other use of the material that
28 dnl constitutes the Autoconf Macro.
30 dnl This special exception to the GPL applies to versions of the
31 dnl Autoconf Macro released by this project. When you make and
32 dnl distribute a modified version of the Autoconf Macro, you may extend
33 dnl this special exception to the GPL to apply to your modified version as
36 dnl Check if FLAG in ENV-VAR is supported by compiler and append it
37 dnl to WHERE-TO-APPEND variable
38 dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG])
40 AC_DEFUN([CC_CHECK_FLAG_APPEND], [
41 AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2],
42 AS_TR_SH([cc_cv_$2_$3]),
43 [eval "AS_TR_SH([cc_save_$2])='${$2}'"
44 eval "AS_TR_SH([$2])='-Werror $3'"
45 AC_LINK_IFELSE([AC_LANG_SOURCE([int a = 0; int main(void) { return a; } ])],
46 [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
47 [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
48 eval "AS_TR_SH([$2])='$cc_save_$2'"])
50 AS_IF([eval test x$]AS_TR_SH([cc_cv_$2_$3])[ = xyes],
51 [eval "$1='${$1} $3'"])
54 dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2])
55 AC_DEFUN([CC_CHECK_FLAGS_APPEND], [
57 CC_CHECK_FLAG_APPEND($1, $2, $flag)
61 dnl Check if the flag is supported by linker (cacheable)
62 dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
64 AC_DEFUN([CC_CHECK_LDFLAGS], [
65 AC_CACHE_CHECK([if $CC supports $1 flag],
66 AS_TR_SH([cc_cv_ldflags_$1]),
67 [ac_save_LDFLAGS="$LDFLAGS"
69 AC_LINK_IFELSE([int main() { return 1; }],
70 [eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"],
71 [eval "AS_TR_SH([cc_cv_ldflags_$1])="])
72 LDFLAGS="$ac_save_LDFLAGS"
75 AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
79 dnl define the LDFLAGS_NOUNDEFINED variable with the correct value for
80 dnl the current linker to avoid undefined references in a shared object.
81 AC_DEFUN([CC_NOUNDEFINED], [
82 dnl We check $host for which systems to enable this for.
83 AC_REQUIRE([AC_CANONICAL_HOST])
86 dnl FreeBSD (et al.) does not complete linking for shared objects when pthreads
87 dnl are requested, as different implementations are present; to avoid problems
88 dnl use -Wl,-z,defs only for those platform not behaving this way.
89 *-freebsd* | *-openbsd*) ;;
91 dnl First of all check for the --no-undefined variant of GNU ld. This allows
92 dnl for a much more readable commandline, so that people can understand what
93 dnl it does without going to look for what the heck -z defs does.
94 for possible_flags in "-Wl,--no-undefined" "-Wl,-z,defs"; do
95 CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"])
101 AC_SUBST([LDFLAGS_NOUNDEFINED])
104 dnl Check for a -Werror flag or equivalent. -Werror is the GCC
105 dnl and ICC flag that tells the compiler to treat all the warnings
106 dnl as fatal. We usually need this option to make sure that some
107 dnl constructs (like attributes) are not simply ignored.
109 dnl Other compilers don't support -Werror per se, but they support
110 dnl an equivalent flag:
111 dnl - Sun Studio compiler supports -errwarn=%all
112 dnl we don't test for that, it gives us false positives when gcc doesn't
113 dnl actually complain about it. If someone wants to compile this on sun, let
115 AC_DEFUN([CC_CHECK_WERROR], [
117 [for $CC way to treat warnings as errors],
119 [CC_CHECK_FLAG_APPEND([cc_cv_werror], [CFLAGS], [-Werror])])
122 AC_DEFUN([CC_CHECK_ATTRIBUTE], [
123 AC_REQUIRE([CC_CHECK_WERROR])
124 AC_CACHE_CHECK([if $CC supports __attribute__(( ifelse([$2], , [$1], [$2]) ))],
125 AS_TR_SH([cc_cv_attribute_$1]),
126 [ac_save_CFLAGS="$CFLAGS"
127 CFLAGS="$CFLAGS $cc_cv_werror"
128 AC_COMPILE_IFELSE([AC_LANG_SOURCE([$3])],
129 [eval "AS_TR_SH([cc_cv_attribute_$1])='yes'"],
130 [eval "AS_TR_SH([cc_cv_attribute_$1])='no'"])
131 CFLAGS="$ac_save_CFLAGS"
134 AS_IF([eval test x$]AS_TR_SH([cc_cv_attribute_$1])[ = xyes],
136 AS_TR_CPP([SUPPORT_ATTRIBUTE_$1]), 1,
137 [Define this if the compiler supports __attribute__(( ifelse([$2], , [$1], [$2]) ))]
143 AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
146 [void __attribute__((constructor)) ctor() { int a; }],
150 AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
152 [format], [format(printf, n, n)],
153 [void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { fmt = (void *)0; }],
157 AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
159 [format_arg], [format_arg(printf)],
160 [char *__attribute__((format_arg(1))) gettextlike(const char *fmt) { fmt = (void *)0; }],
164 AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
166 [visibility_$1], [visibility("$1")],
167 [void __attribute__((visibility("$1"))) $1_function() { }],
171 AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
173 [nonnull], [nonnull()],
174 [void __attribute__((nonnull())) some_function(void *foo, void *bar) { foo = (void*)0; bar = (void*)0; }],
178 AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
181 [void some_function(void *foo, __attribute__((unused)) void *bar);],
185 AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
188 [void some_function(void *foo, ...) __attribute__((sentinel));],
192 AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [
195 [void some_function(void *foo, ...) __attribute__((deprecated));],
199 AC_DEFUN([CC_ATTRIBUTE_ALIAS], [
201 [alias], [weak, alias],
202 [void other_function(void *foo) { }
203 void some_function(void *foo) __attribute__((weak, alias("other_function")));],
207 AC_DEFUN([CC_ATTRIBUTE_MALLOC], [
210 [void * __attribute__((malloc)) my_alloc(int n);],
214 AC_DEFUN([CC_ATTRIBUTE_PACKED], [
217 [struct astructure { char a; int b; long c; void *d; } __attribute__((packed));],
221 AC_DEFUN([CC_ATTRIBUTE_CONST], [
224 [int __attribute__((const)) twopow(int n) { return 1 << n; } ],
228 AC_DEFUN([CC_FLAG_VISIBILITY], [
229 AC_CACHE_CHECK([if $CC supports -fvisibility=hidden],
230 [cc_cv_flag_visibility],
231 [CC_CHECK_FLAG_APPEND([cc_cv_flag_visibility], [CFLAGS], [-fvisibility=hidden])])
233 AS_IF([test "x$cc_cv_flag_visibility" != "x"],
234 [AC_DEFINE([SUPPORT_FLAG_VISIBILITY], 1,
235 [Define this if the compiler supports the -fvisibility flag])
240 AC_DEFUN([CC_FUNC_EXPECT], [
241 AC_REQUIRE([CC_CHECK_WERROR])
242 AC_CACHE_CHECK([if compiler has __builtin_expect function],
244 [ac_save_CFLAGS="$CFLAGS"
245 CFLAGS="$CFLAGS $cc_cv_werror"
246 AC_COMPILE_IFELSE([AC_LANG_SOURCE(
247 [int some_function() {
249 return (int)__builtin_expect(a, 3);
251 [cc_cv_func_expect=yes],
252 [cc_cv_func_expect=no])
253 CFLAGS="$ac_save_CFLAGS"
256 AS_IF([test "x$cc_cv_func_expect" = "xyes"],
257 [AC_DEFINE([SUPPORT__BUILTIN_EXPECT], 1,
258 [Define this if the compiler supports __builtin_expect() function])
263 AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [
264 AC_REQUIRE([CC_CHECK_WERROR])
265 AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported],
266 [cc_cv_attribute_aligned],
267 [ac_save_CFLAGS="$CFLAGS"
268 CFLAGS="$CFLAGS $cc_cv_werror"
269 for cc_attribute_align_try in 64 32 16 8 4 2; do
270 AC_COMPILE_IFELSE([AC_LANG_SOURCE([
272 static char c __attribute__ ((aligned($cc_attribute_align_try))) = 0;
274 }])], [cc_cv_attribute_aligned=$cc_attribute_align_try; break])
276 CFLAGS="$ac_save_CFLAGS"
279 if test "x$cc_cv_attribute_aligned" != "x"; then
280 AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX], [$cc_cv_attribute_aligned],
281 [Define the highest alignment supported])