1 # threadlib.m4 serial 1 (gettext-0.18)
2 dnl Copyright (C) 2005-2008 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 "$gl_use_threads" = posix; then
105 # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
106 # it groks <pthread.h>. It's added above, in gl_THREADLIB_EARLY_BODY.
107 AC_CHECK_HEADER(pthread.h, gl_have_pthread_h=yes, gl_have_pthread_h=no)
108 if test "$gl_have_pthread_h" = yes; then
109 # Other possible tests:
110 # -lpthreads (FSU threads, PCthreads)
113 # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
114 # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
115 # the second one only in libpthread, and lock.c needs it.
116 AC_TRY_LINK([#include <pthread.h>],
117 [pthread_mutex_lock((pthread_mutex_t*)0);
118 pthread_mutexattr_init((pthread_mutexattr_t*)0);],
119 [gl_have_pthread=yes])
120 # Test for libpthread by looking for pthread_kill. (Not pthread_self,
121 # since it is defined as a macro on OSF/1.)
122 if test -n "$gl_have_pthread"; then
123 # The program links fine without libpthread. But it may actually
124 # need to link with libpthread in order to create multiple threads.
125 AC_CHECK_LIB(pthread, pthread_kill,
126 [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread
127 # On Solaris and HP-UX, most pthread functions exist also in libc.
128 # Therefore pthread_in_use() needs to actually try to create a
129 # thread: pthread_create from libc will fail, whereas
130 # pthread_create will actually create a thread.
133 AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], 1,
134 [Define if the pthread_in_use() detection is hard.])
138 # Some library is needed. Try libpthread and libc_r.
139 AC_CHECK_LIB(pthread, pthread_kill,
141 LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread
142 LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread])
143 if test -z "$gl_have_pthread"; then
145 AC_CHECK_LIB(c_r, pthread_kill,
147 LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r
148 LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r])
151 if test -n "$gl_have_pthread"; then
153 AC_DEFINE([USE_POSIX_THREADS], 1,
154 [Define if the POSIX multithreading library can be used.])
155 if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
156 if test $gl_have_weak = yes; then
157 AC_DEFINE([USE_POSIX_THREADS_WEAK], 1,
158 [Define if references to the POSIX multithreading library should be made weak.])
166 if test -z "$gl_have_pthread"; then
167 if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then
168 gl_have_solaristhread=
170 LIBS="$LIBS -lthread"
171 AC_TRY_LINK([#include <thread.h>
174 [gl_have_solaristhread=yes])
176 if test -n "$gl_have_solaristhread"; then
177 gl_threads_api=solaris
180 LIBMULTITHREAD="$LIBTHREAD"
181 LTLIBMULTITHREAD="$LTLIBTHREAD"
182 AC_DEFINE([USE_SOLARIS_THREADS], 1,
183 [Define if the old Solaris multithreading library can be used.])
184 if test $gl_have_weak = yes; then
185 AC_DEFINE([USE_SOLARIS_THREADS_WEAK], 1,
186 [Define if references to the old Solaris multithreading library should be made weak.])
193 if test "$gl_use_threads" = pth; then
194 gl_save_CPPFLAGS="$CPPFLAGS"
195 AC_LIB_LINKFLAGS(pth)
199 AC_TRY_LINK([#include <pth.h>], [pth_self();], gl_have_pth=yes)
201 if test -n "$gl_have_pth"; then
204 LTLIBTHREAD="$LTLIBPTH"
205 LIBMULTITHREAD="$LIBTHREAD"
206 LTLIBMULTITHREAD="$LTLIBTHREAD"
207 AC_DEFINE([USE_PTH_THREADS], 1,
208 [Define if the GNU Pth multithreading library can be used.])
209 if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
210 if test $gl_have_weak = yes; then
211 AC_DEFINE([USE_PTH_THREADS_WEAK], 1,
212 [Define if references to the GNU Pth multithreading library should be made weak.])
218 CPPFLAGS="$gl_save_CPPFLAGS"
221 if test -z "$gl_have_pthread"; then
222 if test "$gl_use_threads" = yes || test "$gl_use_threads" = win32; then
223 if { case "$host_os" in
229 AC_DEFINE([USE_WIN32_THREADS], 1,
230 [Define if the Win32 multithreading API can be used.])
235 AC_MSG_CHECKING([for multithread API to use])
236 AC_MSG_RESULT([$gl_threads_api])
238 AC_SUBST(LTLIBTHREAD)
239 AC_SUBST(LIBMULTITHREAD)
240 AC_SUBST(LTLIBMULTITHREAD)
243 AC_DEFUN([gl_THREADLIB],
245 AC_REQUIRE([gl_THREADLIB_EARLY])
246 AC_REQUIRE([gl_THREADLIB_BODY])
250 dnl gl_DISABLE_THREADS
251 dnl ------------------
252 dnl Sets the gl_THREADLIB default so that threads are not used by default.
253 dnl The user can still override it at installation time, by using the
254 dnl configure option '--enable-threads'.
256 AC_DEFUN([gl_DISABLE_THREADS], [
257 m4_divert_text([INIT_PREPARE], [gl_use_threads_default=no])
261 dnl Survey of platforms:
263 dnl Platform Available Compiler Supports test-lock
264 dnl flavours option weak result
265 dnl --------------- --------- --------- -------- ---------
266 dnl Linux 2.4/glibc posix -lpthread Y OK
268 dnl GNU Hurd/glibc posix
270 dnl FreeBSD 5.3 posix -lc_r Y
272 dnl posix -lpthread ? Y
275 dnl FreeBSD 5.2 posix -lc_r Y
279 dnl FreeBSD 4.0,4.10 posix -lc_r Y OK
283 dnl OpenBSD 3.4 posix -lpthread Y OK
285 dnl MacOS X 10.[123] posix -lpthread Y OK
287 dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK
288 dnl solaris -lthread Y Sol 7,8: 0.0; Sol 9: OK
290 dnl HP-UX 11 posix -lpthread N (cc) OK
293 dnl IRIX 6.5 posix -lpthread Y 0.5
295 dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK
297 dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK
298 dnl -lpthread (gcc) Y
300 dnl Cygwin posix -lpthread Y OK
302 dnl Any of the above pth -lpth 0.0
308 dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
310 dnl OK if all three tests terminate OK,
311 dnl 0.5 if the first test terminates OK but the second one loops endlessly,
312 dnl 0.0 if the first test already loops endlessly.