dnl Defines the macro CAIRO_CONFIGURE_PTHREAD to find a suitable dnl pthread implementation. There are two levels of pthread conformance dnl we are looking for: dnl dnl a) A minimal level denoted by -DCAIRO_HAS_PTHREAD=1: This level dnl requires mutex and recursive mutexattr support. If possible we try dnl to use weakly linked stubs from libc over the real pthread library. dnl This level is required by the cairo library proper. If the user dnl invokes configure with --enable-pthread=yes or dnl --enable-pthread=always then we avoid trying to use weak stubs. dnl dnl b) A full level denoted by -DCAIRO_HAS_REAL_PTHREAD=1: This level dnl requires full support from a real pthread library, including thread dnl creation, joins, thread attribtues, etc. This level is required by dnl multithreaded applications using cairo, such as the test suite dnl binaries and cairo utilities. dnl dnl Usage: dnl CAIRO_ENABLE(pthread, pthread, , dnl [CAIRO_CONFIGURE_PTHREAD]) dnl dnl This should be invoked near the end of configure.ac so that dnl the pthread specific CFLAGS and LIBS end up at the front dnl of CAIRO_CFLAGS and CAIRO_LIBS -- this helps ensure that we dnl really do get non-weak symbols from the actual pthread library dnl rather than possible stubs in other libraries. dnl dnl The user can override the choices made by dnl CAIRO_CONFIGURE_PTHREAD by using --enable-pthread=yes and dnl giving PTHREAD_CFLAGS and PTHREAD_LIBS to configure. dnl dnl Sets environment variables: dnl use_pthread="yes" | "no ()" dnl have_pthread="yes" | "no ( pthread_mutex_t test_mutex_initializer = PTHREAD_MUTEX_INITIALIZER; int test_mutex (void) { int x = 0; pthread_mutex_t mutex; x |= pthread_mutex_init (&mutex, NULL); x |= pthread_mutex_lock (&mutex); x |= pthread_mutex_unlock (&mutex); x |= pthread_mutex_destroy (&mutex); return 0; } int test_mutex_attr (void) { int x = 0; pthread_mutexattr_t attr; pthread_mutex_t mutex; x |= pthread_mutexattr_init (&attr); x |= pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE); x |= pthread_mutex_init (&mutex, &attr); x |= pthread_mutex_lock (&mutex); x |= pthread_mutex_unlock (&mutex); x |= pthread_mutex_destroy (&mutex); x |= pthread_mutexattr_destroy (&attr); return x; }]) dnl ----------------------------------------------------------------------- dnl A program to test all the features we want to be able to run the test dnl suite or other thready cairo applications that want real threads. m4_define([testsuite_pthread_program],[dnl libcairo_pthread_program pthread_once_t once_control = PTHREAD_ONCE_INIT; void test_once_init (void) {} int test_once (void) { return pthread_once (&once_control, test_once_init); } pthread_key_t test_specific_key; int test_specific (void) { int x = 0; x |= pthread_key_create (&test_specific_key, NULL); x |= pthread_setspecific (test_specific_key, NULL); x |= pthread_getspecific (test_specific_key) != NULL; return x; } void cleaner (void *arg) { (void)arg; } void * test_thread_main (void *arg) { pthread_cleanup_push (cleaner, arg); pthread_exit (arg); pthread_cleanup_pop (1); return arg; } int test_threads (void) { int x = 0; pthread_t thread; pthread_attr_t attr; void *arg = NULL; x |= pthread_attr_setdetachstate (&attr, PTHREAD_CREATE_DETACHED); x |= pthread_create (&thread, &attr, test_thread_main, arg); x |= pthread_equal (pthread_self(), thread); x |= pthread_join (thread, &arg); x |= pthread_attr_destroy (&attr); return x; }]) dnl ----------------------------------------------------------------------- dnl CAIRO_CHECK_PTHREAD(tag, cflags, libs, program, true-action, false-action) dnl Set _{CFLAGS,LIBS} to {,} if we can compile and link dnl with the given flags and libs. Execute on dnl success and on failure. AC_DEFUN([CAIRO_CHECK_PTHREAD],[dnl CAIRO_CC_TRY_LINK_WITH_ENV_SILENT( [CFLAGS="$2"; LIBS="$3"], [$4], [$1_CFLAGS="$CFLAGS"; $1_LIBS="$LIBS"; $5], [$1_CFLAGS=""; $1_LIBS=""; $6]) ]) dnl CAIRO_CONFIGURE_PTHREADS(): Look for pthreads. dnl dnl If the user specifies PTHREAD_CFLAGS and PTHREAD_LIBS then we use dnl those. Otherwise we try CFLAGS=-D_REENTRANT and LIBS=-lpthread for dnl full pthread support, and look for stubs in libc for the minimal dnl pthread support. dnl dnl CFLAGS=-D_REENTRANT LIBS=-lpthread has been tested to work on: dnl dnl Solaris 9 (5.9) Sun C 5.8 Patch 121015-04 2007/01/10 dnl OpenSolaris (5.11) Sun C 5.9 Patch 124868-08 2008/11/25 dnl OpenSolaris (5.11) clang version 1.1 (trunk 90017) dnl Tru64/OSF1 V5.1 Compaq C V6.5-003 dnl Mac OS X 10.5.5 gcc 4.0.1 (Apple Inc. build 5465) dnl Mac OS X 10.6 gcc 4.2.1 (Apple Inc. build 5659) dnl FreeBSD 7.2 gcc 4.2 dnl OpenBSD 4.5 gcc 3.3.5 (propolice) dnl Debian Linux (Etch) gcc 4.3 dnl dnl Thread support is also in various libcs directly, so often using no dnl flags at all works as well, but unfortunately Solaris 9 has dnl practically _all_ of libpthread stubbed out in libc, so we cannot dnl distinguish between a working libpthread and a stubbed out one by a dnl link-only test. dnl dnl We also explicitly do not link to pthread-stubs or whatever other dnl third-party stubs library, since that forces cairo clients to be dnl extra careful when giving both libcairo and libpthread on the dnl command line: the user would have to use "-lpthread -lcairo" rather dnl than the more common "-lcairo -lpthread" to not accidentally use dnl stubs pulled in by libcairo everywhere in the application. We dnl might also need to have a way to teach pkg-config about library dnl ordering constraints which aren't actual dependencies, and at this dnl point it just starts doing my head in. dnl dnl If your unix-like doesn't work with the secret handshake dnl -D_REENTRANT -lpthread and you can actually compile the rest of dnl cairo just fine otherwise, please take a moment complain loudly dnl to the cairo mailing list! dnl AC_DEFUN([CAIRO_CONFIGURE_PTHREAD],[dnl dnl Try to use the user's PTHREAD_LIBS/CFLAGS dnl if they're available. if test "x$PTHREAD_CFLAGS" = "x"; then PTHREAD_CFLAGS="-D_REENTRANT" fi if test "x$PTHREAD_LIBS" = "x"; then PTHREAD_LIBS="-lpthread" fi dnl First try to find the real pthreads. CAIRO_CHECK_PTHREAD( [real_pthread], [$PTHREAD_CFLAGS], [$PTHREAD_LIBS], [testsuite_pthread_program], [have_real_pthread=yes], [have_real_pthread=no]) if test "x$have_real_pthread" != "xyes"; then dnl Give -pthread a go. CAIRO_CHECK_PTHREAD( [real_pthread], [-pthread], [], [testsuite_pthread_program], [have_real_pthread=yes], [have_real_pthread="no (can't link with -lpthread or -pthread)"]) fi PTHREAD_CFLAGS= PTHREAD_LIBS= dnl Check if we can use libc's stubs in libcairo. dnl Only do this if the user hasn't explicitly enabled dnl pthreads, but is relying on automatic configuration. have_pthread="no" if test "x$enable_pthread" != "xyes"; then CAIRO_CHECK_PTHREAD( [pthread], [-D_REENTRANT], [], [libcairo_pthread_program], [have_pthread=yes], []) fi dnl Default to using the real pthreads for libcairo. if test "x$have_pthread" != "xyes"; then have_pthread="$have_real_pthread"; pthread_CFLAGS="$real_pthread_CFLAGS"; pthread_LIBS="$real_pthread_LIBS"; fi dnl Tell autoconf about the results. if test "x$have_real_pthread" = "xyes"; then AC_DEFINE([CAIRO_HAS_REAL_PTHREAD], 1, [Define to 1 if we have full pthread support]) fi if test "x$have_pthread" = "xyes"; then AC_DEFINE([CAIRO_HAS_PTHREAD], 1, [Define to 1 f we have minimal pthread support]) fi dnl Make sure we scored some pthreads. if test "x$enable_pthread" = "xyes" -a "x$have_pthread" != "xyes"; then AC_MSG_ERROR([pthread requested but not found]) fi dnl Set the output variables for CAIRO_ENABLE. use_pthread="$have_pthread" pthread_REQUIRES="" ])