# lock.m4 serial 1 (gettext-0.15) dnl Copyright (C) 2005 Free Software Foundation, Inc. dnl This file is free software; the Free Software Foundation dnl gives unlimited permission to copy and/or distribute it, dnl with or without modifications, as long as this notice is preserved. dnl From Bruno Haible. dnl Tests for a multithreading library to be used. dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS, dnl USE_PTH_THREADS, USE_WIN32_THREADS dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with dnl libtool). dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for dnl programs that really need multithread functionality. The difference dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread". AC_DEFUN([gl_LOCK], [ AC_REQUIRE([AC_CANONICAL_HOST]) AC_REQUIRE([AC_GNU_SOURCE]) dnl needed for pthread_rwlock_t on glibc systems dnl Check for multithreading. AC_ARG_ENABLE(threads, AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API]) AC_HELP_STRING([--disable-threads], [build without multithread safety]), gl_use_threads=$enableval, gl_use_threads=yes) gl_threads_api=none LIBTHREAD= LTLIBTHREAD= LIBMULTITHREAD= LTLIBMULTITHREAD= if test "$gl_use_threads" != no; then dnl Check whether the compiler and linker support weak declarations. AC_MSG_CHECKING([whether imported symbols can be declared weak]) gl_have_weak=no AC_TRY_LINK([extern void xyzzy (); #pragma weak xyzzy], [xyzzy();], [gl_have_weak=yes]) AC_MSG_RESULT([$gl_have_weak]) if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that # it groks . gl_save_CPPFLAGS="$CPPFLAGS" CPPFLAGS="$CPPFLAGS -D_REENTRANT" AC_CHECK_HEADER(pthread.h, gl_have_pthread_h=yes, gl_have_pthread_h=no) CPPFLAGS="$gl_save_CPPFLAGS" if test "$gl_have_pthread_h" = yes; then # Other possible tests: # -lpthreads (FSU threads, PCthreads) # -lgthreads case "$host_os" in osf*) # On OSF/1, the compiler needs the flag -pthread so that it groks # . For the linker, it is equivalent to -lpthread. if test -n "$GCC"; then # gcc-2.95 doesn't understand -pthread, only -D_REENTRANT. CPPFLAGS="$CPPFLAGS -D_REENTRANT" else CPPFLAGS="$CPPFLAGS -pthread" fi ;; esac gl_have_pthread= AC_TRY_LINK([#include ], [pthread_mutex_lock((pthread_mutex_t*)0);], [gl_have_pthread=yes]) # Test for libpthread by looking for pthread_kill. (Not pthread_self, # since it is defined as a macro on OSF/1.) if test -n "$gl_have_pthread"; then # The program links fine without libpthread. But it may actually # need to link with libpthread in order to create multiple threads. AC_CHECK_LIB(pthread, pthread_kill, [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread]) else # Some library is needed. Try libpthread and libc_r. AC_CHECK_LIB(pthread, pthread_kill, [gl_have_pthread=yes LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread]) if test -z "$gl_have_pthread"; then # For FreeBSD 4. AC_CHECK_LIB(c_r, pthread_kill, [gl_have_pthread=yes LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r]) fi fi if test -n "$gl_have_pthread"; then gl_threads_api=posix AC_DEFINE([USE_POSIX_THREADS], 1, [Define if the POSIX multithreading library can be used.]) if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then if test $gl_have_weak = yes; then AC_DEFINE([USE_POSIX_THREADS_WEAK], 1, [Define if references to the POSIX multithreading library should be made weak.]) LIBTHREAD= LTLIBTHREAD= fi fi # OSF/1 4.0 and MacOS X 10.1 lack the pthread_rwlock_t type and the # pthread_rwlock_* functions. AC_CHECK_TYPE([pthread_rwlock_t], [AC_DEFINE([HAVE_PTHREAD_RWLOCK], 1, [Define if the POSIX multithreading library has read/write locks.])], [], [#include ]) # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro. AC_TRY_COMPILE([#include ], [#if __FreeBSD__ == 4 error "No, in FreeBSD 4.0 recursive mutexes actually don't work." #else int x = (int)PTHREAD_MUTEX_RECURSIVE; #endif], [AC_DEFINE([HAVE_PTHREAD_MUTEX_RECURSIVE], 1, [Define if the defines PTHREAD_MUTEX_RECURSIVE.])]) # Some systems optimize for single-threaded programs by default, and # need special flags to disable these optimizations. case "$host_os" in aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;; solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;; esac fi fi fi if test -z "$gl_have_pthread"; then if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then gl_have_solaristhread= gl_save_LIBS="$LIBS" LIBS="$LIBS -lthread" AC_TRY_LINK([#include #include ], [thr_self();], [gl_have_solaristhread=yes]) LIBS="$gl_save_LIBS" if test -n "$gl_have_solaristhread"; then gl_threads_api=solaris LIBTHREAD=-lthread LTLIBTHREAD=-lthread LIBMULTITHREAD="$LIBTHREAD" LTLIBMULTITHREAD="$LTLIBTHREAD" AC_DEFINE([USE_SOLARIS_THREADS], 1, [Define if the old Solaris multithreading library can be used.]) if test $gl_have_weak = yes; then AC_DEFINE([USE_SOLARIS_THREADS_WEAK], 1, [Define if references to the old Solaris multithreading library should be made weak.]) LIBTHREAD= LTLIBTHREAD= fi fi fi fi if test "$gl_use_threads" = pth; then gl_save_CPPFLAGS="$CPPFLAGS" AC_LIB_LINKFLAGS(pth) gl_have_pth= gl_save_LIBS="$LIBS" LIBS="$LIBS -lpth" AC_TRY_LINK([#include ], [pth_self();], gl_have_pth=yes) LIBS="$gl_save_LIBS" if test -n "$gl_have_pth"; then gl_threads_api=pth LIBTHREAD="$LIBPTH" LTLIBTHREAD="$LTLIBPTH" LIBMULTITHREAD="$LIBTHREAD" LTLIBMULTITHREAD="$LTLIBTHREAD" AC_DEFINE([USE_PTH_THREADS], 1, [Define if the GNU Pth multithreading library can be used.]) if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then if test $gl_have_weak = yes; then AC_DEFINE([USE_PTH_THREADS_WEAK], 1, [Define if references to the GNU Pth multithreading library should be made weak.]) LIBTHREAD= LTLIBTHREAD= fi fi else CPPFLAGS="$gl_save_CPPFLAGS" fi fi if test -z "$gl_have_pthread"; then if test "$gl_use_threads" = yes || test "$gl_use_threads" = win32; then if { case "$host_os" in mingw*) true;; *) false;; esac }; then gl_threads_api=win32 AC_DEFINE([USE_WIN32_THREADS], 1, [Define if the Win32 multithreading API can be used.]) fi fi fi fi AC_MSG_CHECKING([for multithread API to use]) AC_MSG_RESULT([$gl_threads_api]) AC_SUBST(LIBTHREAD) AC_SUBST(LTLIBTHREAD) AC_SUBST(LIBMULTITHREAD) AC_SUBST(LTLIBMULTITHREAD) gl_PREREQ_LOCK ]) # Prerequisites of lib/lock.c. AC_DEFUN([gl_PREREQ_LOCK], [ AC_REQUIRE([AC_C_INLINE]) ]) dnl Survey of platforms: dnl dnl Platform Available Compiler Supports test-lock dnl flavours option weak result dnl --------------- --------- --------- -------- --------- dnl Linux 2.4/glibc posix -lpthread Y OK dnl dnl GNU Hurd/glibc posix dnl dnl FreeBSD 5.3 posix -lc_r Y dnl posix -lkse ? Y dnl posix -lpthread ? Y dnl posix -lthr Y dnl dnl FreeBSD 5.2 posix -lc_r Y dnl posix -lkse Y dnl posix -lthr Y dnl dnl FreeBSD 4.0,4.10 posix -lc_r Y OK dnl dnl NetBSD 1.6 -- dnl dnl OpenBSD 3.4 posix -lpthread Y OK dnl dnl MacOS X 10.[123] posix -lpthread Y OK dnl dnl Solaris 7,8,9 posix -lpthread Y Sol 7,8: 0.0; Sol 9: OK dnl solaris -lthread Y Sol 7,8: 0.0; Sol 9: OK dnl dnl HP-UX 11 posix -lpthread Y OK dnl dnl IRIX 6.5 posix -lpthread Y 0.5 dnl dnl AIX 4.3,5.1 posix -lpthread N AIX 4: 0.5; AIX 5: OK dnl dnl OSF/1 4.0,5.1 posix -pthread (cc) Y OK dnl -lpthread (gcc) Y dnl dnl Cygwin posix -lpthread Y OK dnl dnl Any of the above pth -lpth 0.0 dnl dnl Mingw win32 N OK dnl dnl BeOS 5 -- dnl dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is dnl turned off: dnl OK if all three tests terminate OK, dnl 0.5 if the first test terminates OK but the second one loops endlessly, dnl 0.0 if the first test already loops endlessly.