1 # threadlib.m4 serial 6 (gettext-0.18.2)
2 dnl Copyright (C) 2005-2010 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"
57 dnl Disable multithreading by default on OSF/1, because it interferes
58 dnl with fork()/exec(): When msgexec is linked with -lpthread, its
59 dnl child process gets an endless segmentation fault inside execvp().
60 dnl Disable multithreading by default on Cygwin 1.5.x, because it has
61 dnl bugs that lead to endless loops or crashes. See
62 dnl <http://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
63 osf*) gl_use_threads=no ;;
66 1.[0-5].*) gl_use_threads=no ;;
67 *) gl_use_threads=yes ;;
70 *) gl_use_threads=yes ;;
75 if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
76 # For using <pthread.h>:
79 # On OSF/1, the compiler needs the flag -D_REENTRANT so that it
80 # groks <pthread.h>. cc also understands the flag -pthread, but
81 # we don't use it because 1. gcc-2.95 doesn't understand -pthread,
82 # 2. putting a flag into CPPFLAGS that has an effect on the linker
83 # causes the AC_LINK_IFELSE test below to succeed unexpectedly,
84 # leading to wrong values of LIBTHREAD and LTLIBTHREAD.
85 CPPFLAGS="$CPPFLAGS -D_REENTRANT"
88 # Some systems optimize for single-threaded programs by default, and
89 # need special flags to disable these optimizations. For example, the
90 # definition of 'errno' in <errno.h>.
92 aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
93 solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
98 dnl The guts of gl_THREADLIB. Needs to be expanded only once.
100 AC_DEFUN([gl_THREADLIB_BODY],
102 AC_REQUIRE([gl_THREADLIB_EARLY_BODY])
108 if test "$gl_use_threads" != no; then
109 dnl Check whether the compiler and linker support weak declarations.
110 AC_CACHE_CHECK([whether imported symbols can be declared weak],
113 dnl First, test whether the compiler accepts it syntactically.
116 [[extern void xyzzy ();
117 #pragma weak xyzzy]],
119 [gl_cv_have_weak=maybe])
120 if test $gl_cv_have_weak = maybe; then
121 dnl Second, test whether it actually works. On Cygwin 1.7.2, with
122 dnl gcc 4.3, symbols declared weak always evaluate to the address 0.
128 return (fputs == NULL);
129 }], [gl_cv_have_weak=yes], [gl_cv_have_weak=no],
130 [dnl When cross-compiling, assume that only ELF platforms support
132 AC_EGREP_CPP([Extensible Linking Format],
134 Extensible Linking Format
137 [gl_cv_have_weak="guessing yes"],
138 [gl_cv_have_weak="guessing no"])
142 if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
143 # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
144 # it groks <pthread.h>. It's added above, in gl_THREADLIB_EARLY_BODY.
145 AC_CHECK_HEADER([pthread.h],
146 [gl_have_pthread_h=yes], [gl_have_pthread_h=no])
147 if test "$gl_have_pthread_h" = yes; then
148 # Other possible tests:
149 # -lpthreads (FSU threads, PCthreads)
152 # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
153 # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
154 # the second one only in libpthread, and lock.c needs it.
157 [[#include <pthread.h>]],
158 [[pthread_mutex_lock((pthread_mutex_t*)0);
159 pthread_mutexattr_init((pthread_mutexattr_t*)0);]])],
160 [gl_have_pthread=yes])
161 # Test for libpthread by looking for pthread_kill. (Not pthread_self,
162 # since it is defined as a macro on OSF/1.)
163 if test -n "$gl_have_pthread"; then
164 # The program links fine without libpthread. But it may actually
165 # need to link with libpthread in order to create multiple threads.
166 AC_CHECK_LIB([pthread], [pthread_kill],
167 [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread
168 # On Solaris and HP-UX, most pthread functions exist also in libc.
169 # Therefore pthread_in_use() needs to actually try to create a
170 # thread: pthread_create from libc will fail, whereas
171 # pthread_create will actually create a thread.
174 AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
175 [Define if the pthread_in_use() detection is hard.])
179 # Some library is needed. Try libpthread and libc_r.
180 AC_CHECK_LIB([pthread], [pthread_kill],
182 LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread
183 LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread])
184 if test -z "$gl_have_pthread"; then
186 AC_CHECK_LIB([c_r], [pthread_kill],
188 LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r
189 LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r])
192 if test -n "$gl_have_pthread"; then
194 AC_DEFINE([USE_POSIX_THREADS], [1],
195 [Define if the POSIX multithreading library can be used.])
196 if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
197 if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
198 AC_DEFINE([USE_POSIX_THREADS_WEAK], [1],
199 [Define if references to the POSIX multithreading library should be made weak.])
207 if test -z "$gl_have_pthread"; then
208 if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then
209 gl_have_solaristhread=
211 LIBS="$LIBS -lthread"
219 [gl_have_solaristhread=yes])
221 if test -n "$gl_have_solaristhread"; then
222 gl_threads_api=solaris
225 LIBMULTITHREAD="$LIBTHREAD"
226 LTLIBMULTITHREAD="$LTLIBTHREAD"
227 AC_DEFINE([USE_SOLARIS_THREADS], [1],
228 [Define if the old Solaris multithreading library can be used.])
229 if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
230 AC_DEFINE([USE_SOLARIS_THREADS_WEAK], [1],
231 [Define if references to the old Solaris multithreading library should be made weak.])
238 if test "$gl_use_threads" = pth; then
239 gl_save_CPPFLAGS="$CPPFLAGS"
240 AC_LIB_LINKFLAGS([pth])
245 [AC_LANG_PROGRAM([[#include <pth.h>]], [[pth_self();]])],
248 if test -n "$gl_have_pth"; then
251 LTLIBTHREAD="$LTLIBPTH"
252 LIBMULTITHREAD="$LIBTHREAD"
253 LTLIBMULTITHREAD="$LTLIBTHREAD"
254 AC_DEFINE([USE_PTH_THREADS], [1],
255 [Define if the GNU Pth multithreading library can be used.])
256 if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
257 if case "$gl_cv_have_weak" in *yes) true;; *) false;; esac; then
258 AC_DEFINE([USE_PTH_THREADS_WEAK], [1],
259 [Define if references to the GNU Pth multithreading library should be made weak.])
265 CPPFLAGS="$gl_save_CPPFLAGS"
268 if test -z "$gl_have_pthread"; then
269 if test "$gl_use_threads" = yes || test "$gl_use_threads" = win32; then
270 if { case "$host_os" in
276 AC_DEFINE([USE_WIN32_THREADS], [1],
277 [Define if the Win32 multithreading API can be used.])
282 AC_MSG_CHECKING([for multithread API to use])
283 AC_MSG_RESULT([$gl_threads_api])
284 AC_SUBST([LIBTHREAD])
285 AC_SUBST([LTLIBTHREAD])
286 AC_SUBST([LIBMULTITHREAD])
287 AC_SUBST([LTLIBMULTITHREAD])
290 AC_DEFUN([gl_THREADLIB],
292 AC_REQUIRE([gl_THREADLIB_EARLY])
293 AC_REQUIRE([gl_THREADLIB_BODY])
297 dnl gl_DISABLE_THREADS
298 dnl ------------------
299 dnl Sets the gl_THREADLIB default so that threads are not used by default.
300 dnl The user can still override it at installation time, by using the
301 dnl configure option '--enable-threads'.
303 AC_DEFUN([gl_DISABLE_THREADS], [
304 m4_divert_text([INIT_PREPARE], [gl_use_threads_default=no])
308 dnl Survey of platforms:
310 dnl Platform Available Compiler Supports test-lock
311 dnl flavours option weak result
312 dnl --------------- --------- --------- -------- ---------
313 dnl Linux 2.4/glibc posix -lpthread Y OK
315 dnl GNU Hurd/glibc posix
317 dnl FreeBSD 5.3 posix -lc_r Y
319 dnl posix -lpthread ? Y
322 dnl FreeBSD 5.2 posix -lc_r Y
326 dnl FreeBSD 4.0,4.10 posix -lc_r Y OK
330 dnl OpenBSD 3.4 posix -lpthread Y OK
332 dnl MacOS X 10.[123] posix -lpthread Y OK
334 dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK
335 dnl solaris -lthread Y Sol 7,8: 0.0; Sol 9: OK
337 dnl HP-UX 11 posix -lpthread N (cc) OK
340 dnl IRIX 6.5 posix -lpthread Y 0.5
342 dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK
344 dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK
345 dnl -lpthread (gcc) Y
347 dnl Cygwin posix -lpthread Y OK
349 dnl Any of the above pth -lpth 0.0
355 dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
357 dnl OK if all three tests terminate OK,
358 dnl 0.5 if the first test terminates OK but the second one loops endlessly,
359 dnl 0.0 if the first test already loops endlessly.