1 # threadlib.m4 serial 3 (gettext-0.18)
2 dnl Copyright (C) 2005-2009 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
11 dnl Tests for a multithreading library to be used.
12 dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS,
13 dnl USE_PTH_THREADS, USE_WIN32_THREADS
14 dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
15 dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
17 dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
18 dnl programs that really need multithread functionality. The difference
19 dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
20 dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread".
21 dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
22 dnl multithread-safe programs.
24 AC_DEFUN([gl_THREADLIB_EARLY],
26 AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
29 dnl The guts of gl_THREADLIB_EARLY. Needs to be expanded only once.
31 AC_DEFUN([gl_THREADLIB_EARLY_BODY],
33 dnl Ordering constraints: This macro modifies CPPFLAGS in a way that
34 dnl influences the result of the autoconf tests that test for *_unlocked
35 dnl declarations, on AIX 5 at least. Therefore it must come early.
36 AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl
37 AC_BEFORE([$0], [gl_ARGP])dnl
39 AC_REQUIRE([AC_CANONICAL_HOST])
40 dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems.
41 dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
43 m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
44 [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
45 [AC_REQUIRE([AC_GNU_SOURCE])])
46 dnl Check for multithreading.
47 m4_divert_text([DEFAULTS], [gl_use_threads_default=])
48 AC_ARG_ENABLE([threads],
49 AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])
50 AC_HELP_STRING([--disable-threads], [build without multithread safety]),
51 [gl_use_threads=$enableval],
52 [if test -n "$gl_use_threads_default"; then
53 gl_use_threads="$gl_use_threads_default"
56 dnl Disable multithreading by default on OSF/1, because it interferes
57 dnl with fork()/exec(): When msgexec is linked with -lpthread, its
58 dnl child process gets an endless segmentation fault inside execvp().
59 osf*) gl_use_threads=no ;;
60 *) gl_use_threads=yes ;;
64 if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
65 # For using <pthread.h>:
68 # On OSF/1, the compiler needs the flag -D_REENTRANT so that it
69 # groks <pthread.h>. cc also understands the flag -pthread, but
70 # we don't use it because 1. gcc-2.95 doesn't understand -pthread,
71 # 2. putting a flag into CPPFLAGS that has an effect on the linker
72 # causes the AC_TRY_LINK test below to succeed unexpectedly,
73 # leading to wrong values of LIBTHREAD and LTLIBTHREAD.
74 CPPFLAGS="$CPPFLAGS -D_REENTRANT"
77 # Some systems optimize for single-threaded programs by default, and
78 # need special flags to disable these optimizations. For example, the
79 # definition of 'errno' in <errno.h>.
81 aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
82 solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
87 dnl The guts of gl_THREADLIB. Needs to be expanded only once.
89 AC_DEFUN([gl_THREADLIB_BODY],
91 AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
97 if test "$gl_use_threads" != no; then
98 dnl Check whether the compiler and linker support weak declarations.
99 AC_MSG_CHECKING([whether imported symbols can be declared weak])
101 AC_TRY_LINK([extern void xyzzy ();
102 #pragma weak xyzzy], [xyzzy();], [gl_have_weak=yes])
103 AC_MSG_RESULT([$gl_have_weak])
104 if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
105 # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
106 # it groks <pthread.h>. It's added above, in gl_THREADLIB_EARLY_BODY.
107 AC_CHECK_HEADER([pthread.h],
108 [gl_have_pthread_h=yes], [gl_have_pthread_h=no])
109 if test "$gl_have_pthread_h" = yes; then
110 # Other possible tests:
111 # -lpthreads (FSU threads, PCthreads)
114 # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
115 # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
116 # the second one only in libpthread, and lock.c needs it.
117 AC_TRY_LINK([#include <pthread.h>],
118 [pthread_mutex_lock((pthread_mutex_t*)0);
119 pthread_mutexattr_init((pthread_mutexattr_t*)0);],
120 [gl_have_pthread=yes])
121 # Test for libpthread by looking for pthread_kill. (Not pthread_self,
122 # since it is defined as a macro on OSF/1.)
123 if test -n "$gl_have_pthread"; then
124 # The program links fine without libpthread. But it may actually
125 # need to link with libpthread in order to create multiple threads.
126 AC_CHECK_LIB([pthread], [pthread_kill],
127 [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread
128 # On Solaris and HP-UX, most pthread functions exist also in libc.
129 # Therefore pthread_in_use() needs to actually try to create a
130 # thread: pthread_create from libc will fail, whereas
131 # pthread_create will actually create a thread.
134 AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
135 [Define if the pthread_in_use() detection is hard.])
139 # Some library is needed. Try libpthread and libc_r.
140 AC_CHECK_LIB([pthread], [pthread_kill],
142 LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread
143 LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread])
144 if test -z "$gl_have_pthread"; then
146 AC_CHECK_LIB([c_r], [pthread_kill],
148 LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r
149 LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r])
152 if test -n "$gl_have_pthread"; then
154 AC_DEFINE([USE_POSIX_THREADS], [1],
155 [Define if the POSIX multithreading library can be used.])
156 if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
157 if test $gl_have_weak = yes; then
158 AC_DEFINE([USE_POSIX_THREADS_WEAK], [1],
159 [Define if references to the POSIX multithreading library should be made weak.])
167 if test -z "$gl_have_pthread"; then
168 if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then
169 gl_have_solaristhread=
171 LIBS="$LIBS -lthread"
172 AC_TRY_LINK([#include <thread.h>
175 [gl_have_solaristhread=yes])
177 if test -n "$gl_have_solaristhread"; then
178 gl_threads_api=solaris
181 LIBMULTITHREAD="$LIBTHREAD"
182 LTLIBMULTITHREAD="$LTLIBTHREAD"
183 AC_DEFINE([USE_SOLARIS_THREADS], [1],
184 [Define if the old Solaris multithreading library can be used.])
185 if test $gl_have_weak = yes; then
186 AC_DEFINE([USE_SOLARIS_THREADS_WEAK], [1],
187 [Define if references to the old Solaris multithreading library should be made weak.])
194 if test "$gl_use_threads" = pth; then
195 gl_save_CPPFLAGS="$CPPFLAGS"
196 AC_LIB_LINKFLAGS([pth])
200 AC_TRY_LINK([#include <pth.h>], [pth_self();], [gl_have_pth=yes])
202 if test -n "$gl_have_pth"; then
205 LTLIBTHREAD="$LTLIBPTH"
206 LIBMULTITHREAD="$LIBTHREAD"
207 LTLIBMULTITHREAD="$LTLIBTHREAD"
208 AC_DEFINE([USE_PTH_THREADS], [1],
209 [Define if the GNU Pth multithreading library can be used.])
210 if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
211 if test $gl_have_weak = yes; then
212 AC_DEFINE([USE_PTH_THREADS_WEAK], [1],
213 [Define if references to the GNU Pth multithreading library should be made weak.])
219 CPPFLAGS="$gl_save_CPPFLAGS"
222 if test -z "$gl_have_pthread"; then
223 if test "$gl_use_threads" = yes || test "$gl_use_threads" = win32; then
224 if { case "$host_os" in
230 AC_DEFINE([USE_WIN32_THREADS], [1],
231 [Define if the Win32 multithreading API can be used.])
236 AC_MSG_CHECKING([for multithread API to use])
237 AC_MSG_RESULT([$gl_threads_api])
238 AC_SUBST([LIBTHREAD])
239 AC_SUBST([LTLIBTHREAD])
240 AC_SUBST([LIBMULTITHREAD])
241 AC_SUBST([LTLIBMULTITHREAD])
244 AC_DEFUN([gl_THREADLIB],
246 AC_REQUIRE([gl_THREADLIB_EARLY])
247 AC_REQUIRE([gl_THREADLIB_BODY])
251 dnl gl_DISABLE_THREADS
252 dnl ------------------
253 dnl Sets the gl_THREADLIB default so that threads are not used by default.
254 dnl The user can still override it at installation time, by using the
255 dnl configure option '--enable-threads'.
257 AC_DEFUN([gl_DISABLE_THREADS], [
258 m4_divert_text([INIT_PREPARE], [gl_use_threads_default=no])
262 dnl Survey of platforms:
264 dnl Platform Available Compiler Supports test-lock
265 dnl flavours option weak result
266 dnl --------------- --------- --------- -------- ---------
267 dnl Linux 2.4/glibc posix -lpthread Y OK
269 dnl GNU Hurd/glibc posix
271 dnl FreeBSD 5.3 posix -lc_r Y
273 dnl posix -lpthread ? Y
276 dnl FreeBSD 5.2 posix -lc_r Y
280 dnl FreeBSD 4.0,4.10 posix -lc_r Y OK
284 dnl OpenBSD 3.4 posix -lpthread Y OK
286 dnl MacOS X 10.[123] posix -lpthread Y OK
288 dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK
289 dnl solaris -lthread Y Sol 7,8: 0.0; Sol 9: OK
291 dnl HP-UX 11 posix -lpthread N (cc) OK
294 dnl IRIX 6.5 posix -lpthread Y 0.5
296 dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK
298 dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK
299 dnl -lpthread (gcc) Y
301 dnl Cygwin posix -lpthread Y OK
303 dnl Any of the above pth -lpth 0.0
309 dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
311 dnl OK if all three tests terminate OK,
312 dnl 0.5 if the first test terminates OK but the second one loops endlessly,
313 dnl 0.0 if the first test already loops endlessly.