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. Note that we invert -Wno-* checks to
38 dnl -W* as gcc cannot test for negated warnings. If a C snippet is passed,
39 dnl use it, otherwise use a simple main() definition that just returns 0.
40 dnl CC_CHECK_FLAG_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG], [C-SNIPPET])
42 AC_DEFUN([CC_CHECK_FLAG_APPEND], [
43 AC_CACHE_CHECK([if $CC supports flag $3 in envvar $2],
44 AS_TR_SH([cc_cv_$2_$3]),
45 [eval "AS_TR_SH([cc_save_$2])='${$2}'"
46 eval "AS_TR_SH([$2])='${cc_save_$2} -Werror `echo "$3" | sed 's/^-Wno-/-W/'`'"
47 AC_LINK_IFELSE([AC_LANG_SOURCE(ifelse([$4], [],
48 [int main(void) { return 0; } ],
50 [eval "AS_TR_SH([cc_cv_$2_$3])='yes'"],
51 [eval "AS_TR_SH([cc_cv_$2_$3])='no'"])
52 eval "AS_TR_SH([$2])='$cc_save_$2'"])
54 AS_IF([eval test x$]AS_TR_SH([cc_cv_$2_$3])[ = xyes],
55 [eval "$1='${$1} $3'"])
58 dnl CC_CHECK_FLAGS_APPEND([WHERE-TO-APPEND], [ENV-VAR], [FLAG1 FLAG2], [C-SNIPPET])
59 AC_DEFUN([CC_CHECK_FLAGS_APPEND], [
61 CC_CHECK_FLAG_APPEND([$1], [$2], $flag, [$4])
65 dnl Check if the flag is supported by linker (cacheable)
66 dnl CC_CHECK_LDFLAGS([FLAG], [ACTION-IF-FOUND],[ACTION-IF-NOT-FOUND])
68 AC_DEFUN([CC_CHECK_LDFLAGS], [
69 AC_CACHE_CHECK([if $CC supports $1 flag],
70 AS_TR_SH([cc_cv_ldflags_$1]),
71 [ac_save_LDFLAGS="$LDFLAGS"
73 AC_LINK_IFELSE([AC_LANG_SOURCE([int main() { return 1; }])],
74 [eval "AS_TR_SH([cc_cv_ldflags_$1])='yes'"],
75 [eval "AS_TR_SH([cc_cv_ldflags_$1])="])
76 LDFLAGS="$ac_save_LDFLAGS"
79 AS_IF([eval test x$]AS_TR_SH([cc_cv_ldflags_$1])[ = xyes],
83 dnl define the LDFLAGS_NOUNDEFINED variable with the correct value for
84 dnl the current linker to avoid undefined references in a shared object.
85 AC_DEFUN([CC_NOUNDEFINED], [
86 dnl We check $host for which systems to enable this for.
87 AC_REQUIRE([AC_CANONICAL_HOST])
90 dnl FreeBSD (et al.) does not complete linking for shared objects when pthreads
91 dnl are requested, as different implementations are present; to avoid problems
92 dnl use -Wl,-z,defs only for those platform not behaving this way.
93 *-freebsd* | *-openbsd*) ;;
95 dnl First of all check for the --no-undefined variant of GNU ld. This allows
96 dnl for a much more readable command line, so that people can understand what
97 dnl it does without going to look for what the heck -z defs does.
98 for possible_flags in "-Wl,--no-undefined" "-Wl,-z,defs"; do
99 CC_CHECK_LDFLAGS([$possible_flags], [LDFLAGS_NOUNDEFINED="$possible_flags"])
105 AC_SUBST([LDFLAGS_NOUNDEFINED])
108 dnl Check for a -Werror flag or equivalent. -Werror is the GCC
109 dnl and ICC flag that tells the compiler to treat all the warnings
110 dnl as fatal. We usually need this option to make sure that some
111 dnl constructs (like attributes) are not simply ignored.
113 dnl Other compilers don't support -Werror per se, but they support
114 dnl an equivalent flag:
115 dnl - Sun Studio compiler supports -errwarn=%all
116 AC_DEFUN([CC_CHECK_WERROR], [
118 [for $CC way to treat warnings as errors],
120 [CC_CHECK_CFLAGS_SILENT([-Werror], [cc_cv_werror=-Werror],
121 [CC_CHECK_CFLAGS_SILENT([-errwarn=%all], [cc_cv_werror=-errwarn=%all])])
125 AC_DEFUN([CC_CHECK_ATTRIBUTE], [
126 AC_REQUIRE([CC_CHECK_WERROR])
127 AC_CACHE_CHECK([if $CC supports __attribute__(( ifelse([$2], , [$1], [$2]) ))],
128 AS_TR_SH([cc_cv_attribute_$1]),
129 [ac_save_CFLAGS="$CFLAGS"
130 CFLAGS="$CFLAGS $cc_cv_werror"
131 AC_COMPILE_IFELSE([AC_LANG_SOURCE([$3])],
132 [eval "AS_TR_SH([cc_cv_attribute_$1])='yes'"],
133 [eval "AS_TR_SH([cc_cv_attribute_$1])='no'"])
134 CFLAGS="$ac_save_CFLAGS"
137 AS_IF([eval test x$]AS_TR_SH([cc_cv_attribute_$1])[ = xyes],
139 AS_TR_CPP([SUPPORT_ATTRIBUTE_$1]), 1,
140 [Define this if the compiler supports __attribute__(( ifelse([$2], , [$1], [$2]) ))]
146 AC_DEFUN([CC_ATTRIBUTE_CONSTRUCTOR], [
149 [void __attribute__((constructor)) ctor() { int a; }],
153 AC_DEFUN([CC_ATTRIBUTE_FORMAT], [
155 [format], [format(printf, n, n)],
156 [void __attribute__((format(printf, 1, 2))) printflike(const char *fmt, ...) { fmt = (void *)0; }],
160 AC_DEFUN([CC_ATTRIBUTE_FORMAT_ARG], [
162 [format_arg], [format_arg(printf)],
163 [char *__attribute__((format_arg(1))) gettextlike(const char *fmt) { fmt = (void *)0; }],
167 AC_DEFUN([CC_ATTRIBUTE_VISIBILITY], [
169 [visibility_$1], [visibility("$1")],
170 [void __attribute__((visibility("$1"))) $1_function() { }],
174 AC_DEFUN([CC_ATTRIBUTE_NONNULL], [
176 [nonnull], [nonnull()],
177 [void __attribute__((nonnull())) some_function(void *foo, void *bar) { foo = (void*)0; bar = (void*)0; }],
181 AC_DEFUN([CC_ATTRIBUTE_UNUSED], [
184 [void some_function(void *foo, __attribute__((unused)) void *bar);],
188 AC_DEFUN([CC_ATTRIBUTE_SENTINEL], [
191 [void some_function(void *foo, ...) __attribute__((sentinel));],
195 AC_DEFUN([CC_ATTRIBUTE_DEPRECATED], [
198 [void some_function(void *foo, ...) __attribute__((deprecated));],
202 AC_DEFUN([CC_ATTRIBUTE_ALIAS], [
204 [alias], [weak, alias],
205 [void other_function(void *foo) { }
206 void some_function(void *foo) __attribute__((weak, alias("other_function")));],
210 AC_DEFUN([CC_ATTRIBUTE_MALLOC], [
213 [void * __attribute__((malloc)) my_alloc(int n);],
217 AC_DEFUN([CC_ATTRIBUTE_PACKED], [
220 [struct astructure { char a; int b; long c; void *d; } __attribute__((packed));],
224 AC_DEFUN([CC_ATTRIBUTE_CONST], [
227 [int __attribute__((const)) twopow(int n) { return 1 << n; } ],
231 AC_DEFUN([CC_FLAG_VISIBILITY], [
232 AC_REQUIRE([CC_CHECK_WERROR])
233 AC_CACHE_CHECK([if $CC supports -fvisibility=hidden],
234 [cc_cv_flag_visibility],
235 [cc_flag_visibility_save_CFLAGS="$CFLAGS"
236 CFLAGS="$CFLAGS $cc_cv_werror"
237 CC_CHECK_CFLAGS_SILENT([-fvisibility=hidden],
238 cc_cv_flag_visibility='yes',
239 cc_cv_flag_visibility='no')
240 CFLAGS="$cc_flag_visibility_save_CFLAGS"])
242 AS_IF([test "x$cc_cv_flag_visibility" = "xyes"],
243 [AC_DEFINE([SUPPORT_FLAG_VISIBILITY], 1,
244 [Define this if the compiler supports the -fvisibility flag])
249 AC_DEFUN([CC_FUNC_EXPECT], [
250 AC_REQUIRE([CC_CHECK_WERROR])
251 AC_CACHE_CHECK([if compiler has __builtin_expect function],
253 [ac_save_CFLAGS="$CFLAGS"
254 CFLAGS="$CFLAGS $cc_cv_werror"
255 AC_COMPILE_IFELSE([AC_LANG_SOURCE(
256 [int some_function() {
258 return (int)__builtin_expect(a, 3);
260 [cc_cv_func_expect=yes],
261 [cc_cv_func_expect=no])
262 CFLAGS="$ac_save_CFLAGS"
265 AS_IF([test "x$cc_cv_func_expect" = "xyes"],
266 [AC_DEFINE([SUPPORT__BUILTIN_EXPECT], 1,
267 [Define this if the compiler supports __builtin_expect() function])
272 AC_DEFUN([CC_ATTRIBUTE_ALIGNED], [
273 AC_REQUIRE([CC_CHECK_WERROR])
274 AC_CACHE_CHECK([highest __attribute__ ((aligned ())) supported],
275 [cc_cv_attribute_aligned],
276 [ac_save_CFLAGS="$CFLAGS"
277 CFLAGS="$CFLAGS $cc_cv_werror"
278 for cc_attribute_align_try in 64 32 16 8 4 2; do
279 AC_COMPILE_IFELSE([AC_LANG_SOURCE([
281 static char c __attribute__ ((aligned($cc_attribute_align_try))) = 0;
283 }])], [cc_cv_attribute_aligned=$cc_attribute_align_try; break])
285 CFLAGS="$ac_save_CFLAGS"
288 if test "x$cc_cv_attribute_aligned" != "x"; then
289 AC_DEFINE_UNQUOTED([ATTRIBUTE_ALIGNED_MAX], [$cc_cv_attribute_aligned],
290 [Define the highest alignment supported])