1 dnl ---------------------------------------------------------------------------
3 dnl Macros for configure.in for wxWindows by Robert Roebling, Phil Blecker,
4 dnl Vadim Zeitlin and Ron Lee
6 dnl This script is under the wxWindows licence.
9 dnl ---------------------------------------------------------------------------
12 dnl ===========================================================================
13 dnl Objective-C(++) related macros
14 dnl ===========================================================================
15 m4_define([AC_WX_LANG_OBJECTIVEC],
20 m4_define([AC_WX_LANG_OBJECTIVECPLUSPLUS],
25 dnl ===========================================================================
26 dnl macros to find the a file in the list of include/lib paths
27 dnl ===========================================================================
29 dnl ---------------------------------------------------------------------------
30 dnl call WX_PATH_FIND_INCLUDES(search path, header name), sets ac_find_includes
31 dnl to the full name of the file that was found or leaves it empty if not found
32 dnl ---------------------------------------------------------------------------
33 AC_DEFUN([WX_PATH_FIND_INCLUDES],
36 for ac_dir in $1 /usr/include;
38 if test -f "$ac_dir/$2"; then
39 ac_find_includes=$ac_dir
45 dnl ---------------------------------------------------------------------------
46 dnl call WX_PATH_FIND_LIBRARIES(search path, lib name), sets ac_find_libraries
47 dnl to the full name of the file that was found or leaves it empty if not found
48 dnl ---------------------------------------------------------------------------
49 AC_DEFUN([WX_PATH_FIND_LIBRARIES],
54 for ac_extension in a so sl dylib dll.a; do
55 if test -f "$ac_dir/lib$2.$ac_extension"; then
56 ac_find_libraries=$ac_dir
63 dnl ---------------------------------------------------------------------------
64 dnl return list of standard library paths
65 dnl ---------------------------------------------------------------------------
66 dnl return all default locations:
67 dnl - /usr/lib: standard
68 dnl - /usr/lib32: n32 ABI on IRIX
69 dnl - /usr/lib64: n64 ABI on IRIX
70 dnl - /usr/lib/64: 64 bit ABI on Solaris and Linux x86-64
72 dnl NB: if any of directories in the list is not a subdir of /usr, code setting
73 dnl wx_cv_std_libpath needs to be updated
74 AC_DEFUN([WX_STD_LIBPATH], [/usr/lib /usr/lib32 /usr/lib/64 /usr/lib64])
76 dnl ---------------------------------------------------------------------------
77 dnl Path to include, already defined
78 dnl ---------------------------------------------------------------------------
79 AC_DEFUN([WX_INCLUDE_PATH_EXIST],
81 dnl never add -I/usr/include to the CPPFLAGS
82 if test "x$1" = "x/usr/include"; then
85 echo "$2" | grep "\-I$1" > /dev/null
87 if test $result = 0; then
90 ac_path_to_include=" -I$1"
95 dnl ---------------------------------------------------------------------------
96 dnl Usage: WX_LINK_PATH_EXIST(path, libpath)
98 dnl Set ac_path_to_link to nothing if path is already in libpath of to -Lpath
99 dnl if it is not, so that libpath can be set to "$libpath$ac_path_to_link"
100 dnl after calling this function
101 dnl ---------------------------------------------------------------------------
102 AC_DEFUN([WX_LINK_PATH_EXIST],
104 dnl never add -L/usr/libXXX explicitely to libpath
105 if test "$1" = "default location"; then
108 echo "$2" | grep "\-L$1" > /dev/null
110 if test $result = 0; then
113 ac_path_to_link=" -L$1"
118 dnl ===========================================================================
119 dnl C++ features test
120 dnl ===========================================================================
122 dnl ---------------------------------------------------------------------------
123 dnl WX_CPP_NEW_HEADERS checks whether the compiler has "new" <iostream> header
124 dnl or only the old <iostream.h> one - it may be generally assumed that if
125 dnl <iostream> exists, the other "new" headers (without .h) exist too.
127 dnl call WX_CPP_NEW_HEADERS(actiof-if-true, action-if-false)
128 dnl ---------------------------------------------------------------------------
130 AC_DEFUN([WX_CPP_NEW_HEADERS],
135 AC_CHECK_HEADERS(iostream)
137 if test "$ac_cv_header_iostream" = "yes" ; then
138 ifelse([$1], , :, [$1])
140 ifelse([$2], , :, [$2])
146 dnl ---------------------------------------------------------------------------
147 dnl WX_CPP_BOOL checks whether the C++ compiler has a built in bool type
149 dnl call WX_CPP_BOOL - will define HAVE_BOOL if the compiler supports bool
150 dnl ---------------------------------------------------------------------------
152 AC_DEFUN([WX_CPP_BOOL],
154 AC_CACHE_CHECK([if C++ compiler supports bool], wx_cv_cpp_bool,
178 if test "$wx_cv_cpp_bool" = "yes"; then
183 dnl ---------------------------------------------------------------------------
184 dnl WX_CPP_EXPLICIT checks whether the C++ compiler support the explicit
185 dnl keyword and defines HAVE_EXPLICIT if this is the case
186 dnl ---------------------------------------------------------------------------
188 AC_DEFUN([WX_CPP_EXPLICIT],
190 AC_CACHE_CHECK([if C++ compiler supports the explicit keyword],
196 dnl do the test in 2 steps: first check that the compiler knows about the
197 dnl explicit keyword at all and then verify that it really honours it
200 class Foo { public: explicit Foo(int) {} };
208 class Foo { public: explicit Foo(int) {} };
209 static void TakeFoo(const Foo& foo) { }
225 if test "$wx_cv_explicit" = "yes"; then
226 AC_DEFINE(HAVE_EXPLICIT)
230 dnl ---------------------------------------------------------------------------
231 dnl WX_CHECK_FUNCS(FUNCTIONS...,
232 dnl [ACTION-IF-FOUND],
233 dnl [ACTION-IF-NOT-FOUND],
234 dnl [EXTRA-DEFINES-AND-INCLUDES],
235 dnl [EXTRA-TEST-CODE])
237 dnl Checks that the functions listed in FUNCTIONS exist in the headers and the
238 dnl libs. For each function, if it is found then defines 'HAVE_FUNCTION' and
239 dnl executes ACTION-IF-FOUND, otherwise executes ACTION-IF-NOT-FOUND.
241 dnl The code from EXTRA-DEFINES-AND-INCLUDES is inserted into the test before
242 dnl the default headers are included, and EXTRA-TEST-CODE is inserted into
243 dnl the main() function after the default test for existence.
246 dnl # the simple case
247 dnl WX_CHECK_FUNCS(stat)
248 dnl # use break to finish the loop early
249 dnl WX_CHECK_FUNCS(mkstemp mktemp, break)
251 dnl WX_CHECK_FUNCS(strtok_r, [], [], [#define _RREENTRANT])
253 dnl WX_CHECK_FUNCS(swprintf, [], [], [#include <wchar.h>])
254 dnl # checking the signature with extra test code
255 dnl WX_CHECK_FUNCS(gettimeofday, [], [], [#include <sys/time.h>]
256 dnl [struct timeval tv; struct timezone tz; gettimeofday(&tv, &tz)])
257 dnl ---------------------------------------------------------------------------
259 AC_DEFUN([WX_CHECK_FUNCS],
265 [wx_cv_func_$wx_func],
281 [eval wx_cv_func_$wx_func=yes],
282 [eval wx_cv_func_$wx_func=no])
285 if eval test \$wx_cv_func_$wx_func = yes
287 AC_DEFINE_UNQUOTED([HAVE_`echo $wx_func | tr 'a-z' 'A-Z'`])
296 dnl ---------------------------------------------------------------------------
297 dnl a slightly better AC_C_BIGENDIAN macro which allows cross-compiling
298 dnl ---------------------------------------------------------------------------
300 AC_DEFUN([WX_C_BIGENDIAN],
301 [AC_CACHE_CHECK([whether byte ordering is bigendian], ac_cv_c_bigendian,
302 [ac_cv_c_bigendian=unknown
303 # See if sys/param.h defines the BYTE_ORDER macro.
304 AC_TRY_COMPILE([#include <sys/types.h>
305 #include <sys/param.h>], [
306 #if !BYTE_ORDER || !BIG_ENDIAN || !LITTLE_ENDIAN
308 #endif], [# It does; now see whether it defined to BIG_ENDIAN or not.
309 AC_TRY_COMPILE([#include <sys/types.h>
310 #include <sys/param.h>], [
311 #if BYTE_ORDER != BIG_ENDIAN
313 #endif], ac_cv_c_bigendian=yes, ac_cv_c_bigendian=no)])
314 if test $ac_cv_c_bigendian = unknown; then
315 AC_TRY_RUN([main () {
316 /* Are we little or big endian? From Harbison&Steele. */
320 char c[sizeof (long)];
323 exit (u.c[sizeof (long) - 1] == 1);
324 }], [ac_cv_c_bigendian=no], [ac_cv_c_bigendian=yes], [ac_cv_c_bigendian=unknown])
326 if test $ac_cv_c_bigendian = unknown; then
327 AC_MSG_WARN([Assuming little-endian target machine - this may be overriden by adding the line "ac_cv_c_bigendian=${ac_cv_c_bigendian='yes'}" to config.cache file])
329 if test $ac_cv_c_bigendian = yes; then
330 AC_DEFINE(WORDS_BIGENDIAN)
334 dnl ---------------------------------------------------------------------------
335 dnl override AC_ARG_ENABLE/WITH to cache the results in .cache file
336 dnl ---------------------------------------------------------------------------
338 AC_DEFUN([WX_ARG_CACHE_INIT],
340 wx_arg_cache_file="configarg.cache"
341 echo "loading argument cache $wx_arg_cache_file"
342 rm -f ${wx_arg_cache_file}.tmp
343 touch ${wx_arg_cache_file}.tmp
344 touch ${wx_arg_cache_file}
347 AC_DEFUN([WX_ARG_CACHE_FLUSH],
349 echo "saving argument cache $wx_arg_cache_file"
350 mv ${wx_arg_cache_file}.tmp ${wx_arg_cache_file}
353 dnl this macro checks for a three-valued command line --with argument:
354 dnl possible arguments are 'yes', 'no', 'sys', or 'builtin'
355 dnl usage: WX_ARG_SYS_WITH(option, helpmessage, variable-name)
356 AC_DEFUN([WX_ARG_SYS_WITH],
358 AC_MSG_CHECKING([for --with-$1])
360 AC_ARG_WITH($1, [$2],
362 if test "$withval" = yes; then
363 ac_cv_use_$1='$3=yes'
364 elif test "$withval" = no; then
366 elif test "$withval" = sys; then
367 ac_cv_use_$1='$3=sys'
368 elif test "$withval" = builtin; then
369 ac_cv_use_$1='$3=builtin'
371 AC_MSG_ERROR([Invalid value for --with-$1: should be yes, no, sys, or builtin])
375 LINE=`grep "$3" ${wx_arg_cache_file}`
376 if test "x$LINE" != x ; then
382 ac_cv_use_$1='$3='$DEFAULT_$3
386 if test "$no_cache" != 1; then
387 echo $ac_cv_use_$1 >> ${wx_arg_cache_file}.tmp
390 if test "$$3" = yes; then
392 elif test "$$3" = no; then
394 elif test "$$3" = sys; then
395 AC_MSG_RESULT([system version])
396 elif test "$$3" = builtin; then
397 AC_MSG_RESULT([builtin version])
399 AC_MSG_ERROR([Invalid value for --with-$1: should be yes, no, sys, or builtin])
403 dnl this macro checks for a command line argument and caches the result
404 dnl usage: WX_ARG_WITH(option, helpmessage, variable-name, [withstring])
405 AC_DEFUN([WX_ARG_WITH],
408 AC_MSG_CHECKING([for --${withstring:-with}-$1])
410 AC_ARG_WITH($1, [$2],
412 if test "$withval" = yes; then
413 ac_cv_use_$1='$3=yes'
419 LINE=`grep "$3" ${wx_arg_cache_file}`
420 if test "x$LINE" != x ; then
426 ac_cv_use_$1='$3='$DEFAULT_$3
430 if test "$no_cache" != 1; then
431 echo $ac_cv_use_$1 >> ${wx_arg_cache_file}.tmp
434 if test "$$3" = yes; then
441 dnl like WX_ARG_WITH but uses AC_ARG_ENABLE instead of AC_ARG_WITH
442 dnl usage: WX_ARG_ENABLE(option, helpmessage, variable-name, enablestring)
444 dnl enablestring is a hack and allows to show "checking for --disable-foo"
445 dnl message when running configure instead of the default "checking for
446 dnl --enable-foo" one whih is useful for the options enabled by default
447 AC_DEFUN([WX_ARG_ENABLE],
450 AC_MSG_CHECKING([for --${enablestring:-enable}-$1])
452 AC_ARG_ENABLE($1, [$2],
454 if test "$enableval" = yes; then
455 ac_cv_use_$1='$3=yes'
461 LINE=`grep "$3" ${wx_arg_cache_file}`
462 if test "x$LINE" != x ; then
468 ac_cv_use_$1='$3='$DEFAULT_$3
472 if test "$no_cache" != 1; then
473 echo $ac_cv_use_$1 >> ${wx_arg_cache_file}.tmp
476 if test "$$3" = yes; then
484 dnl Like WX_ARG_ENABLE but accepts a parameter.
487 dnl WX_ARG_ENABLE_PARAM(option, helpmessage, variable-name, enablestring)
490 dnl WX_ARG_ENABLE_PARAM(foo, [[ --enable-foo[=bar] use foo]], wxUSE_FOO)
492 dnl --enable-foo wxUSE_FOO=yes
493 dnl --disable-foo wxUSE_FOO=no
494 dnl --enable-foo=bar wxUSE_FOO=bar
495 dnl <not given> value from configarg.cache or wxUSE_FOO=no
497 AC_DEFUN([WX_ARG_ENABLE_PARAM],
500 AC_MSG_CHECKING([for --${enablestring:-enable}-$1])
502 AC_ARG_ENABLE($1, [$2],
504 wx_cv_use_$1="$3='$enableval'"
507 LINE=`grep "$3" ${wx_arg_cache_file}`
508 if test "x$LINE" != x ; then
510 wx_cv_use_$1='$3='$DEFAULT_$3
518 if test "$no_cache" != 1; then
519 echo $wx_cv_use_$1 >> ${wx_arg_cache_file}.tmp
525 dnl ===========================================================================
526 dnl Linker features test
527 dnl ===========================================================================
529 dnl ---------------------------------------------------------------------------
530 dnl WX_VERSIONED_SYMBOLS checks whether the linker can create versioned
531 dnl symbols. If it can, sets LDFLAGS_VERSIONING to $CXX flags needed to use
532 dnl version script file named versionfile
534 dnl call WX_VERSIONED_SYMBOLS(versionfile)
535 dnl ---------------------------------------------------------------------------
536 AC_DEFUN([WX_VERSIONED_SYMBOLS],
540 dnl FIXME - doesn't work, Solaris linker doesn't accept wildcards
542 dnl dnl Check for known non-gcc cases:
543 dnl case "${host}" in
545 dnl if test "x$GCC" != "xyes" ; then
546 dnl LDFLAGS_VERSIONING="-M $1"
547 dnl found_versioning=yes
552 dnl Generic check for GCC or GCC-like behaviour (Intel C++, GCC):
553 if test $found_versioning = no ; then
554 AC_CACHE_CHECK([if the linker accepts --version-script], wx_cv_version_script,
556 echo "VER_1 { *; };" >conftest.sym
557 echo "int main() { return 0; }" >conftest.cpp
560 $CXX -o conftest.output $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.cpp
561 -Wl,--version-script,conftest.sym >/dev/null 2>conftest.stderr]) ; then
562 if test -s conftest.stderr ; then
563 wx_cv_version_script=no
565 wx_cv_version_script=yes
568 wx_cv_version_script=no
571 dnl There's a problem in some old linkers with --version-script that
572 dnl can cause linking to fail when you have objects with vtables in
573 dnl libs 3 deep. This is known to happen in netbsd and openbsd with
576 dnl To test for this we need to make some shared libs and
577 dnl unfortunately we can't be sure of the right way to do that. If the
578 dnl first two compiles don't succeed then it looks like the test isn't
579 dnl working and the result is ignored, but if OTOH the first two
580 dnl succeed but the third does not then the bug has been detected and
581 dnl the --version-script flag is dropped.
582 if test $wx_cv_version_script = yes
584 echo "struct B { virtual ~B() { } }; \
585 struct D : public B { }; \
586 void F() { D d; }" > conftest.cpp
589 $CXX -shared -fPIC -o conftest1.output $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.cpp
590 -Wl,--version-script,conftest.sym >/dev/null 2>/dev/null]) &&
592 $CXX -shared -fPIC -o conftest2.output $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.cpp
593 -Wl,--version-script,conftest.sym conftest1.output >/dev/null 2>/dev/null])
596 $CXX -shared -fPIC -o conftest3.output $CXXFLAGS $CPPFLAGS $LDFLAGS conftest.cpp
597 -Wl,--version-script,conftest.sym conftest2.output conftest1.output >/dev/null 2>/dev/null])
599 wx_cv_version_script=yes
601 wx_cv_version_script=no
606 rm -f conftest.output conftest.stderr conftest.sym conftest.cpp
607 rm -f conftest1.output conftest2.output conftest3.output
609 if test $wx_cv_version_script = yes ; then
610 LDFLAGS_VERSIONING="-Wl,--version-script,$1"
616 dnl ===========================================================================
617 dnl "3rd party" macros included here because they are not widely available
618 dnl ===========================================================================
620 dnl ---------------------------------------------------------------------------
621 dnl test for availability of iconv()
622 dnl ---------------------------------------------------------------------------
624 dnl From Bruno Haible.
628 dnl Some systems have iconv in libc, some have it in libiconv (OSF/1 and
629 dnl those with the standalone portable GNU libiconv installed).
631 AC_ARG_WITH([libiconv-prefix],
632 [ --with-libiconv-prefix=DIR search for libiconv in DIR/include and DIR/lib], [
633 for dir in `echo "$withval" | tr : ' '`; do
634 if test -d $dir/include; then CPPFLAGS="$CPPFLAGS -I$dir/include"; fi
635 if test -d $dir/lib; then LDFLAGS="$LDFLAGS -L$dir/lib"; fi
639 AC_CACHE_CHECK(for iconv, am_cv_func_iconv, [
640 am_cv_func_iconv="no, consider installing GNU libiconv"
642 AC_TRY_LINK([#include <stdlib.h>
644 [iconv_t cd = iconv_open("","");
645 iconv(cd,NULL,NULL,NULL,NULL);
647 am_cv_func_iconv=yes)
648 if test "$am_cv_func_iconv" != yes; then
651 AC_TRY_LINK([#include <stdlib.h>
653 [iconv_t cd = iconv_open("","");
654 iconv(cd,NULL,NULL,NULL,NULL);
657 am_cv_func_iconv=yes)
661 if test "$am_cv_func_iconv" = yes; then
662 AC_DEFINE(HAVE_ICONV, 1, [Define if you have the iconv() function.])
663 AC_CACHE_CHECK([if iconv needs const], wx_cv_func_iconv_const,
671 #if defined(__STDC__) || defined(__cplusplus)
672 size_t iconv (iconv_t cd, char * *inbuf, size_t *inbytesleft, char * *outbuf, size_t *outbytesleft);
678 wx_cv_func_iconv_const="no",
679 wx_cv_func_iconv_const="yes"
684 if test "x$wx_cv_func_iconv_const" = "xyes"; then
688 AC_DEFINE_UNQUOTED(ICONV_CONST, $iconv_const,
689 [Define as const if the declaration of iconv() needs const.])
692 if test "$am_cv_lib_iconv" = yes; then
698 dnl ---------------------------------------------------------------------------
699 dnl AC_SYS_LARGEFILE (partly based on the code from autoconf 2.5x)
700 dnl ---------------------------------------------------------------------------
702 dnl WX_SYS_LARGEFILE_TEST
704 dnl NB: original autoconf test was checking if compiler supported 6 bit off_t
705 dnl arithmetic properly but this failed miserably with gcc under Linux
706 dnl whereas the system still supports 64 bit files, so now simply check
707 dnl that off_t is big enough
708 define(WX_SYS_LARGEFILE_TEST,
710 unsigned int field: sizeof(off_t) == 8;
715 dnl WX_SYS_LARGEFILE_MACRO_VALUE(C-MACRO, VALUE, CACHE-VAR)
716 define(WX_SYS_LARGEFILE_MACRO_VALUE,
718 AC_CACHE_CHECK([for $1 value needed for large files], [$3],
720 AC_TRY_COMPILE([#define $1 $2
721 #include <sys/types.h>],
722 WX_SYS_LARGEFILE_TEST,
728 if test "$$3" != no; then
730 AC_DEFINE_UNQUOTED([$1], [$$3])
737 dnl By default, many hosts won't let programs access large files;
738 dnl one must use special compiler options to get large-file access to work.
739 dnl For more details about this brain damage please see:
740 dnl http://www.sas.com/standards/large.file/x_open.20Mar96.html
741 AC_DEFUN([AC_SYS_LARGEFILE],
742 [AC_ARG_ENABLE(largefile,
743 [ --disable-largefile omit support for large files])
744 if test "$enable_largefile" != no; then
745 dnl _FILE_OFFSET_BITS==64 is needed for Linux, Solaris, ...
746 dnl _LARGE_FILES -- for AIX
748 WX_SYS_LARGEFILE_MACRO_VALUE(_FILE_OFFSET_BITS, 64, ac_cv_sys_file_offset_bits)
749 if test "x$wx_largefile" != "xyes"; then
750 WX_SYS_LARGEFILE_MACRO_VALUE(_LARGE_FILES, 1, ac_cv_sys_large_files)
753 AC_MSG_CHECKING(if large file support is available)
754 if test "x$wx_largefile" = "xyes"; then
755 AC_DEFINE(HAVE_LARGEFILE_SUPPORT)
757 AC_MSG_RESULT($wx_largefile)
762 dnl Available from the GNU Autoconf Macro Archive at:
763 dnl http://www.gnu.org/software/ac-archive/htmldoc/ac_cxx_const_cast.html
765 AC_DEFUN([AC_CXX_CONST_CAST],
766 [AC_CACHE_CHECK(whether the compiler supports const_cast<>,
767 ac_cv_cxx_const_cast,
770 AC_TRY_COMPILE(,[int x = 0;const int& y = x;int& z = const_cast<int&>(y);return z;],
771 ac_cv_cxx_const_cast=yes, ac_cv_cxx_const_cast=no)
774 if test "$ac_cv_cxx_const_cast" = yes; then
775 AC_DEFINE(HAVE_CONST_CAST,,[define if the compiler supports const_cast<>])
779 dnl http://www.gnu.org/software/ac-archive/htmldoc/ac_cxx_reinterpret_cast.html
780 AC_DEFUN([AC_CXX_REINTERPRET_CAST],
781 [AC_CACHE_CHECK(whether the compiler supports reinterpret_cast<>,
782 ac_cv_cxx_reinterpret_cast,
785 AC_TRY_COMPILE([#include <typeinfo>
786 class Base { public : Base () {} virtual void f () = 0;};
787 class Derived : public Base { public : Derived () {} virtual void f () {} };
788 class Unrelated { public : Unrelated () {} };
789 int g (Unrelated&) { return 0; }],[
790 Derived d;Base& b=d;Unrelated& e=reinterpret_cast<Unrelated&>(b);return g(e);],
791 ac_cv_cxx_reinterpret_cast=yes, ac_cv_cxx_reinterpret_cast=no)
794 if test "$ac_cv_cxx_reinterpret_cast" = yes; then
795 AC_DEFINE(HAVE_REINTERPRET_CAST,,
796 [define if the compiler supports reinterpret_cast<>])
800 dnl and http://www.gnu.org/software/ac-archive/htmldoc/ac_cxx_static_cast.html
801 AC_DEFUN([AC_CXX_STATIC_CAST],
802 [AC_CACHE_CHECK(whether the compiler supports static_cast<>,
803 ac_cv_cxx_static_cast,
806 AC_TRY_COMPILE([#include <typeinfo>
807 class Base { public : Base () {} virtual void f () = 0; };
808 class Derived : public Base { public : Derived () {} virtual void f () {} };
809 int g (Derived&) { return 0; }],[
810 Derived d; Base& b = d; Derived& s = static_cast<Derived&> (b); return g (s);],
811 ac_cv_cxx_static_cast=yes, ac_cv_cxx_static_cast=no)
814 if test "$ac_cv_cxx_static_cast" = yes; then
815 AC_DEFINE(HAVE_STATIC_CAST,, [define if the compiler supports static_cast<>])
819 dnl http://autoconf-archive.cryp.to/ac_cxx_dynamic_cast.html
820 AC_DEFUN([AC_CXX_DYNAMIC_CAST],
821 [AC_CACHE_CHECK(whether the compiler supports dynamic_cast<>,
822 ac_cv_cxx_dynamic_cast,
825 AC_TRY_COMPILE([#include <typeinfo>
826 class Base { public : Base () {} virtual void f () = 0;};
827 class Derived : public Base { public : Derived () {} virtual void f () {} };],[
828 Derived d; Base& b=d; return dynamic_cast<Derived*>(&b) ? 0 : 1;],
829 ac_cv_cxx_dynamic_cast=yes, ac_cv_cxx_dynamic_cast=no)
832 if test "$ac_cv_cxx_dynamic_cast" = yes; then
833 AC_DEFINE(HAVE_DYNAMIC_CAST,,[define if the compiler supports dynamic_cast<>])