1
# lock.m4 serial 2 (gettext-0.15)
2
dnl Copyright (C) 2005 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.
9
dnl Tests for a multithreading library to be used.
10
dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS,
11
dnl USE_PTH_THREADS, USE_WIN32_THREADS
12
dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
13
dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
15
dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
16
dnl programs that really need multithread functionality. The difference
17
dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
18
dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread".
19
dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
20
dnl multithread-safe programs.
24
AC_REQUIRE([gl_LOCK_BODY])
27
dnl The guts of gl_LOCK. Needs to be expanded only once.
29
AC_DEFUN([gl_LOCK_BODY],
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([$0], [gl_ARGP])dnl
37
AC_REQUIRE([AC_CANONICAL_HOST])
38
AC_REQUIRE([AC_GNU_SOURCE]) dnl needed for pthread_rwlock_t on glibc systems
39
dnl Check for multithreading.
40
AC_ARG_ENABLE(threads,
41
AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])
42
AC_HELP_STRING([--disable-threads], [build without multithread safety]),
43
gl_use_threads=$enableval, gl_use_threads=yes)
49
if test "$gl_use_threads" != no; then
50
dnl Check whether the compiler and linker support weak declarations.
51
AC_MSG_CHECKING([whether imported symbols can be declared weak])
53
AC_TRY_LINK([extern void xyzzy ();
54
#pragma weak xyzzy], [xyzzy();], [gl_have_weak=yes])
55
AC_MSG_RESULT([$gl_have_weak])
56
if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
57
# On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
58
# it groks <pthread.h>.
59
gl_save_CPPFLAGS="$CPPFLAGS"
60
CPPFLAGS="$CPPFLAGS -D_REENTRANT"
61
AC_CHECK_HEADER(pthread.h, gl_have_pthread_h=yes, gl_have_pthread_h=no)
62
CPPFLAGS="$gl_save_CPPFLAGS"
63
if test "$gl_have_pthread_h" = yes; then
64
# Other possible tests:
65
# -lpthreads (FSU threads, PCthreads)
69
# On OSF/1, the compiler needs the flag -D_REENTRANT so that it
70
# groks <pthread.h>. cc also understands the flag -pthread, but
71
# we don't use it because 1. gcc-2.95 doesn't understand -pthread,
72
# 2. putting a flag into CPPFLAGS that has an effect on the linker
73
# causes the AC_TRY_LINK test below to succeed unexpectedly,
74
# leading to wrong values of LIBTHREAD and LTLIBTHREAD.
75
CPPFLAGS="$CPPFLAGS -D_REENTRANT"
79
# Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
80
# in libc. IRIX 6.5 has the first one in both libc and libpthread, but
81
# the second one only in libpthread, and lock.c needs it.
82
AC_TRY_LINK([#include <pthread.h>],
83
[pthread_mutex_lock((pthread_mutex_t*)0);
84
pthread_mutexattr_init((pthread_mutexattr_t*)0);],
85
[gl_have_pthread=yes])
86
# Test for libpthread by looking for pthread_kill. (Not pthread_self,
87
# since it is defined as a macro on OSF/1.)
88
if test -n "$gl_have_pthread"; then
89
# The program links fine without libpthread. But it may actually
90
# need to link with libpthread in order to create multiple threads.
91
AC_CHECK_LIB(pthread, pthread_kill,
92
[LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread
93
# On Solaris and HP-UX, most pthread functions exist also in libc.
94
# Therefore pthread_in_use() needs to actually try to create a
95
# thread: pthread_create from libc will fail, whereas
96
# pthread_create will actually create a thread.
99
AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], 1,
100
[Define if the pthread_in_use() detection is hard.])
104
# Some library is needed. Try libpthread and libc_r.
105
AC_CHECK_LIB(pthread, pthread_kill,
107
LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread
108
LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread])
109
if test -z "$gl_have_pthread"; then
111
AC_CHECK_LIB(c_r, pthread_kill,
113
LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r
114
LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r])
117
if test -n "$gl_have_pthread"; then
119
AC_DEFINE([USE_POSIX_THREADS], 1,
120
[Define if the POSIX multithreading library can be used.])
121
if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
122
if test $gl_have_weak = yes; then
123
AC_DEFINE([USE_POSIX_THREADS_WEAK], 1,
124
[Define if references to the POSIX multithreading library should be made weak.])
129
# OSF/1 4.0 and MacOS X 10.1 lack the pthread_rwlock_t type and the
130
# pthread_rwlock_* functions.
131
AC_CHECK_TYPE([pthread_rwlock_t],
132
[AC_DEFINE([HAVE_PTHREAD_RWLOCK], 1,
133
[Define if the POSIX multithreading library has read/write locks.])],
135
[#include <pthread.h>])
136
# glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.
137
AC_TRY_COMPILE([#include <pthread.h>],
138
[#if __FreeBSD__ == 4
139
error "No, in FreeBSD 4.0 recursive mutexes actually don't work."
141
int x = (int)PTHREAD_MUTEX_RECURSIVE;
143
[AC_DEFINE([HAVE_PTHREAD_MUTEX_RECURSIVE], 1,
144
[Define if the <pthread.h> defines PTHREAD_MUTEX_RECURSIVE.])])
145
# Some systems optimize for single-threaded programs by default, and
146
# need special flags to disable these optimizations. For example, the
147
# definition of 'errno' in <errno.h>.
149
aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
150
solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
155
if test -z "$gl_have_pthread"; then
156
if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then
157
gl_have_solaristhread=
159
LIBS="$LIBS -lthread"
160
AC_TRY_LINK([#include <thread.h>
163
[gl_have_solaristhread=yes])
165
if test -n "$gl_have_solaristhread"; then
166
gl_threads_api=solaris
169
LIBMULTITHREAD="$LIBTHREAD"
170
LTLIBMULTITHREAD="$LTLIBTHREAD"
171
AC_DEFINE([USE_SOLARIS_THREADS], 1,
172
[Define if the old Solaris multithreading library can be used.])
173
if test $gl_have_weak = yes; then
174
AC_DEFINE([USE_SOLARIS_THREADS_WEAK], 1,
175
[Define if references to the old Solaris multithreading library should be made weak.])
182
if test "$gl_use_threads" = pth; then
183
gl_save_CPPFLAGS="$CPPFLAGS"
184
AC_LIB_LINKFLAGS(pth)
188
AC_TRY_LINK([#include <pth.h>], [pth_self();], gl_have_pth=yes)
190
if test -n "$gl_have_pth"; then
193
LTLIBTHREAD="$LTLIBPTH"
194
LIBMULTITHREAD="$LIBTHREAD"
195
LTLIBMULTITHREAD="$LTLIBTHREAD"
196
AC_DEFINE([USE_PTH_THREADS], 1,
197
[Define if the GNU Pth multithreading library can be used.])
198
if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
199
if test $gl_have_weak = yes; then
200
AC_DEFINE([USE_PTH_THREADS_WEAK], 1,
201
[Define if references to the GNU Pth multithreading library should be made weak.])
207
CPPFLAGS="$gl_save_CPPFLAGS"
210
if test -z "$gl_have_pthread"; then
211
if test "$gl_use_threads" = yes || test "$gl_use_threads" = win32; then
212
if { case "$host_os" in
218
AC_DEFINE([USE_WIN32_THREADS], 1,
219
[Define if the Win32 multithreading API can be used.])
224
AC_MSG_CHECKING([for multithread API to use])
225
AC_MSG_RESULT([$gl_threads_api])
227
AC_SUBST(LTLIBTHREAD)
228
AC_SUBST(LIBMULTITHREAD)
229
AC_SUBST(LTLIBMULTITHREAD)
233
# Prerequisites of lib/lock.c.
234
AC_DEFUN([gl_PREREQ_LOCK], [
235
AC_REQUIRE([AC_C_INLINE])
238
dnl Survey of platforms:
240
dnl Platform Available Compiler Supports test-lock
241
dnl flavours option weak result
242
dnl --------------- --------- --------- -------- ---------
243
dnl Linux 2.4/glibc posix -lpthread Y OK
245
dnl GNU Hurd/glibc posix
247
dnl FreeBSD 5.3 posix -lc_r Y
249
dnl posix -lpthread ? Y
252
dnl FreeBSD 5.2 posix -lc_r Y
256
dnl FreeBSD 4.0,4.10 posix -lc_r Y OK
260
dnl OpenBSD 3.4 posix -lpthread Y OK
262
dnl MacOS X 10.[123] posix -lpthread Y OK
264
dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK
265
dnl solaris -lthread Y Sol 7,8: 0.0; Sol 9: OK
267
dnl HP-UX 11 posix -lpthread N (cc) OK
270
dnl IRIX 6.5 posix -lpthread Y 0.5
272
dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK
274
dnl OSF/1 4.0,5.1 posix -pthread (cc) N OK
275
dnl -lpthread (gcc) Y
277
dnl Cygwin posix -lpthread Y OK
279
dnl Any of the above pth -lpth 0.0
285
dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
287
dnl OK if all three tests terminate OK,
288
dnl 0.5 if the first test terminates OK but the second one loops endlessly,
289
dnl 0.0 if the first test already loops endlessly.