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1# lock.m4 serial 6 (gettext-0.16)
2dnl Copyright (C) 2005-2006 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl From Bruno Haible.
8
9dnl Tests for a multithreading library to be used.
10dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS,
11dnl USE_PTH_THREADS, USE_WIN32_THREADS
12dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
13dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
14dnl libtool).
15dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
16dnl programs that really need multithread functionality. The difference
17dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
18dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread".
19dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
20dnl multithread-safe programs.
21
22AC_DEFUN([gl_LOCK_EARLY],
23[
24 AC_REQUIRE([gl_LOCK_EARLY_BODY])
25])
26
27dnl The guts of gl_LOCK_EARLY. Needs to be expanded only once.
28
29AC_DEFUN([gl_LOCK_EARLY_BODY],
30[
31 dnl Ordering constraints: This macro modifies CPPFLAGS in a way that
32 dnl influences the result of the autoconf tests that test for *_unlocked
33 dnl declarations, on AIX 5 at least. Therefore it must come early.
34 AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl
35 AC_BEFORE([$0], [gl_ARGP])dnl
36
37 AC_REQUIRE([AC_CANONICAL_HOST])
38 AC_REQUIRE([AC_GNU_SOURCE]) dnl needed for pthread_rwlock_t on glibc systems
39 dnl Check for multithreading.
40 AC_ARG_ENABLE(threads,
41AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])
42AC_HELP_STRING([--disable-threads], [build without multithread safety]),
43 [gl_use_threads=$enableval],
44 [case "$host_os" in
45 dnl Disable multithreading by default on OSF/1, because it interferes
46 dnl with fork()/exec(): When msgexec is linked with -lpthread, its child
47 dnl process gets an endless segmentation fault inside execvp().
48 osf*) gl_use_threads=no ;;
49 *) gl_use_threads=yes ;;
50 esac
51 ])
52 if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
53 # For using <pthread.h>:
54 case "$host_os" in
55 osf*)
56 # On OSF/1, the compiler needs the flag -D_REENTRANT so that it
57 # groks <pthread.h>. cc also understands the flag -pthread, but
58 # we don't use it because 1. gcc-2.95 doesn't understand -pthread,
59 # 2. putting a flag into CPPFLAGS that has an effect on the linker
60 # causes the AC_TRY_LINK test below to succeed unexpectedly,
61 # leading to wrong values of LIBTHREAD and LTLIBTHREAD.
62 CPPFLAGS="$CPPFLAGS -D_REENTRANT"
63 ;;
64 esac
65 # Some systems optimize for single-threaded programs by default, and
66 # need special flags to disable these optimizations. For example, the
67 # definition of 'errno' in <errno.h>.
68 case "$host_os" in
69 aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
70 solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
71 esac
72 fi
73])
74
75dnl The guts of gl_LOCK. Needs to be expanded only once.
76
77AC_DEFUN([gl_LOCK_BODY],
78[
79 AC_REQUIRE([gl_LOCK_EARLY_BODY])
80 gl_threads_api=none
81 LIBTHREAD=
82 LTLIBTHREAD=
83 LIBMULTITHREAD=
84 LTLIBMULTITHREAD=
85 if test "$gl_use_threads" != no; then
86 dnl Check whether the compiler and linker support weak declarations.
87 AC_MSG_CHECKING([whether imported symbols can be declared weak])
88 gl_have_weak=no
89 AC_TRY_LINK([extern void xyzzy ();
90#pragma weak xyzzy], [xyzzy();], [gl_have_weak=yes])
91 AC_MSG_RESULT([$gl_have_weak])
92 if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
93 # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
94 # it groks <pthread.h>. It's added above, in gl_LOCK_EARLY_BODY.
95 AC_CHECK_HEADER(pthread.h, gl_have_pthread_h=yes, gl_have_pthread_h=no)
96 if test "$gl_have_pthread_h" = yes; then
97 # Other possible tests:
98 # -lpthreads (FSU threads, PCthreads)
99 # -lgthreads
100 gl_have_pthread=
101 # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
102 # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
103 # the second one only in libpthread, and lock.c needs it.
104 AC_TRY_LINK([#include <pthread.h>],
105 [pthread_mutex_lock((pthread_mutex_t*)0);
106 pthread_mutexattr_init((pthread_mutexattr_t*)0);],
107 [gl_have_pthread=yes])
108 # Test for libpthread by looking for pthread_kill. (Not pthread_self,
109 # since it is defined as a macro on OSF/1.)
110 if test -n "$gl_have_pthread"; then
111 # The program links fine without libpthread. But it may actually
112 # need to link with libpthread in order to create multiple threads.
113 AC_CHECK_LIB(pthread, pthread_kill,
114 [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread
115 # On Solaris and HP-UX, most pthread functions exist also in libc.
116 # Therefore pthread_in_use() needs to actually try to create a
117 # thread: pthread_create from libc will fail, whereas
118 # pthread_create will actually create a thread.
119 case "$host_os" in
120 solaris* | hpux*)
121 AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], 1,
122 [Define if the pthread_in_use() detection is hard.])
123 esac
124 ])
125 else
126 # Some library is needed. Try libpthread and libc_r.
127 AC_CHECK_LIB(pthread, pthread_kill,
128 [gl_have_pthread=yes
129 LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread
130 LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread])
131 if test -z "$gl_have_pthread"; then
132 # For FreeBSD 4.
133 AC_CHECK_LIB(c_r, pthread_kill,
134 [gl_have_pthread=yes
135 LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r
136 LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r])
137 fi
138 fi
139 if test -n "$gl_have_pthread"; then
140 gl_threads_api=posix
141 AC_DEFINE([USE_POSIX_THREADS], 1,
142 [Define if the POSIX multithreading library can be used.])
143 if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
144 if test $gl_have_weak = yes; then
145 AC_DEFINE([USE_POSIX_THREADS_WEAK], 1,
146 [Define if references to the POSIX multithreading library should be made weak.])
147 LIBTHREAD=
148 LTLIBTHREAD=
149 fi
150 fi
151 # OSF/1 4.0 and MacOS X 10.1 lack the pthread_rwlock_t type and the
152 # pthread_rwlock_* functions.
153 AC_CHECK_TYPE([pthread_rwlock_t],
154 [AC_DEFINE([HAVE_PTHREAD_RWLOCK], 1,
155 [Define if the POSIX multithreading library has read/write locks.])],
156 [],
157 [#include <pthread.h>])
158 # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.
159 AC_TRY_COMPILE([#include <pthread.h>],
160 [#if __FreeBSD__ == 4
161error "No, in FreeBSD 4.0 recursive mutexes actually don't work."
162#else
163int x = (int)PTHREAD_MUTEX_RECURSIVE;
164return !x;
165#endif],
166 [AC_DEFINE([HAVE_PTHREAD_MUTEX_RECURSIVE], 1,
167 [Define if the <pthread.h> defines PTHREAD_MUTEX_RECURSIVE.])])
168 fi
169 fi
170 fi
171 if test -z "$gl_have_pthread"; then
172 if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then
173 gl_have_solaristhread=
174 gl_save_LIBS="$LIBS"
175 LIBS="$LIBS -lthread"
176 AC_TRY_LINK([#include <thread.h>
177#include <synch.h>],
178 [thr_self();],
179 [gl_have_solaristhread=yes])
180 LIBS="$gl_save_LIBS"
181 if test -n "$gl_have_solaristhread"; then
182 gl_threads_api=solaris
183 LIBTHREAD=-lthread
184 LTLIBTHREAD=-lthread
185 LIBMULTITHREAD="$LIBTHREAD"
186 LTLIBMULTITHREAD="$LTLIBTHREAD"
187 AC_DEFINE([USE_SOLARIS_THREADS], 1,
188 [Define if the old Solaris multithreading library can be used.])
189 if test $gl_have_weak = yes; then
190 AC_DEFINE([USE_SOLARIS_THREADS_WEAK], 1,
191 [Define if references to the old Solaris multithreading library should be made weak.])
192 LIBTHREAD=
193 LTLIBTHREAD=
194 fi
195 fi
196 fi
197 fi
198 if test "$gl_use_threads" = pth; then
199 gl_save_CPPFLAGS="$CPPFLAGS"
200 AC_LIB_LINKFLAGS(pth)
201 gl_have_pth=
202 gl_save_LIBS="$LIBS"
203 LIBS="$LIBS -lpth"
204 AC_TRY_LINK([#include <pth.h>], [pth_self();], gl_have_pth=yes)
205 LIBS="$gl_save_LIBS"
206 if test -n "$gl_have_pth"; then
207 gl_threads_api=pth
208 LIBTHREAD="$LIBPTH"
209 LTLIBTHREAD="$LTLIBPTH"
210 LIBMULTITHREAD="$LIBTHREAD"
211 LTLIBMULTITHREAD="$LTLIBTHREAD"
212 AC_DEFINE([USE_PTH_THREADS], 1,
213 [Define if the GNU Pth multithreading library can be used.])
214 if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
215 if test $gl_have_weak = yes; then
216 AC_DEFINE([USE_PTH_THREADS_WEAK], 1,
217 [Define if references to the GNU Pth multithreading library should be made weak.])
218 LIBTHREAD=
219 LTLIBTHREAD=
220 fi
221 fi
222 else
223 CPPFLAGS="$gl_save_CPPFLAGS"
224 fi
225 fi
226 if test -z "$gl_have_pthread"; then
227 if test "$gl_use_threads" = yes || test "$gl_use_threads" = win32; then
228 if { case "$host_os" in
229 mingw*) true;;
230 *) false;;
231 esac
232 }; then
233 gl_threads_api=win32
234 AC_DEFINE([USE_WIN32_THREADS], 1,
235 [Define if the Win32 multithreading API can be used.])
236 fi
237 fi
238 fi
239 fi
240 AC_MSG_CHECKING([for multithread API to use])
241 AC_MSG_RESULT([$gl_threads_api])
242 AC_SUBST(LIBTHREAD)
243 AC_SUBST(LTLIBTHREAD)
244 AC_SUBST(LIBMULTITHREAD)
245 AC_SUBST(LTLIBMULTITHREAD)
246])
247
248AC_DEFUN([gl_LOCK],
249[
250 AC_REQUIRE([gl_LOCK_EARLY])
251 AC_REQUIRE([gl_LOCK_BODY])
252 gl_PREREQ_LOCK
253])
254
255# Prerequisites of lib/lock.c.
256AC_DEFUN([gl_PREREQ_LOCK], [
257 AC_REQUIRE([AC_C_INLINE])
258])
259
260dnl Survey of platforms:
261dnl
262dnl Platform Available Compiler Supports test-lock
263dnl flavours option weak result
264dnl --------------- --------- --------- -------- ---------
265dnl Linux 2.4/glibc posix -lpthread Y OK
266dnl
267dnl GNU Hurd/glibc posix
268dnl
269dnl FreeBSD 5.3 posix -lc_r Y
270dnl posix -lkse ? Y
271dnl posix -lpthread ? Y
272dnl posix -lthr Y
273dnl
274dnl FreeBSD 5.2 posix -lc_r Y
275dnl posix -lkse Y
276dnl posix -lthr Y
277dnl
278dnl FreeBSD 4.0,4.10 posix -lc_r Y OK
279dnl
280dnl NetBSD 1.6 --
281dnl
282dnl OpenBSD 3.4 posix -lpthread Y OK
283dnl
284dnl MacOS X 10.[123] posix -lpthread Y OK
285dnl
286dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK
287dnl solaris -lthread Y Sol 7,8: 0.0; Sol 9: OK
288dnl
289dnl HP-UX 11 posix -lpthread N (cc) OK
290dnl Y (gcc)
291dnl
292dnl IRIX 6.5 posix -lpthread Y 0.5
293dnl
294dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK
295dnl
296dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK
297dnl -lpthread (gcc) Y
298dnl
299dnl Cygwin posix -lpthread Y OK
300dnl
301dnl Any of the above pth -lpth 0.0
302dnl
303dnl Mingw win32 N OK
304dnl
305dnl BeOS 5 --
306dnl
307dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
308dnl turned off:
309dnl OK if all three tests terminate OK,
310dnl 0.5 if the first test terminates OK but the second one loops endlessly,
311dnl 0.0 if the first test already loops endlessly.