1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
4 * gthread.c: posix thread system implementation
5 * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
22 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
23 * file for a list of people on the GLib Team. See the ChangeLog
24 * files for a list of changes. These files are distributed with
25 * GLib at ftp://ftp.gtk.org/pub/gtk/.
28 /* The GMutex, GCond and GPrivate implementations in this file are some
29 * of the lowest-level code in GLib. All other parts of GLib (messages,
30 * memory, slices, etc) assume that they can freely use these facilities
31 * without risking recursion.
33 * As such, these functions are NOT permitted to call any other part of
36 * The thread manipulation functions (create, exit, join, etc.) have
37 * more freedom -- they can do as they please.
44 #include "gthreadprivate.h"
46 #include "gmessages.h"
47 #include "gstrfuncs.h"
62 #ifdef HAVE_SYS_PRCTL_H
63 #include <sys/prctl.h>
70 g_thread_abort (gint status,
71 const gchar *function)
73 fprintf (stderr, "GLib (gthread-posix.c): Unexpected error from C library during '%s': %s. Aborting.\n",
74 function, strerror (status));
80 static pthread_mutex_t *
81 g_mutex_impl_new (void)
83 pthread_mutexattr_t *pattr = NULL;
84 pthread_mutex_t *mutex;
87 mutex = malloc (sizeof (pthread_mutex_t));
88 if G_UNLIKELY (mutex == NULL)
89 g_thread_abort (errno, "malloc");
91 #ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
93 pthread_mutexattr_t attr;
94 pthread_mutexattr_init (&attr);
95 pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_ADAPTIVE_NP);
100 if G_UNLIKELY ((status = pthread_mutex_init (mutex, pattr)) != 0)
101 g_thread_abort (status, "pthread_mutex_init");
103 #ifdef PTHREAD_ADAPTIVE_MUTEX_NP
104 pthread_mutexattr_destroy (&attr);
111 g_mutex_impl_free (pthread_mutex_t *mutex)
113 pthread_mutex_destroy (mutex);
117 static pthread_mutex_t *
118 g_mutex_get_impl (GMutex *mutex)
120 pthread_mutex_t *impl = g_atomic_pointer_get (&mutex->p);
122 if G_UNLIKELY (impl == NULL)
124 impl = g_mutex_impl_new ();
125 if (!g_atomic_pointer_compare_and_exchange (&mutex->p, NULL, impl))
126 g_mutex_impl_free (impl);
136 * @mutex: an uninitialized #GMutex
138 * Initializes a #GMutex so that it can be used.
140 * This function is useful to initialize a mutex that has been
141 * allocated on the stack, or as part of a larger structure.
142 * It is not necessary to initialize a mutex that has been
143 * statically allocated.
145 * |[<!-- language="C" -->
153 * b = g_new (Blob, 1);
154 * g_mutex_init (&b->m);
157 * To undo the effect of g_mutex_init() when a mutex is no longer
158 * needed, use g_mutex_clear().
160 * Calling g_mutex_init() on an already initialized #GMutex leads
161 * to undefined behaviour.
166 g_mutex_init (GMutex *mutex)
168 mutex->p = g_mutex_impl_new ();
173 * @mutex: an initialized #GMutex
175 * Frees the resources allocated to a mutex with g_mutex_init().
177 * This function should not be used with a #GMutex that has been
178 * statically allocated.
180 * Calling g_mutex_clear() on a locked mutex leads to undefined
186 g_mutex_clear (GMutex *mutex)
188 g_mutex_impl_free (mutex->p);
195 * Locks @mutex. If @mutex is already locked by another thread, the
196 * current thread will block until @mutex is unlocked by the other
199 * #GMutex is neither guaranteed to be recursive nor to be
200 * non-recursive. As such, calling g_mutex_lock() on a #GMutex that has
201 * already been locked by the same thread results in undefined behaviour
202 * (including but not limited to deadlocks).
205 g_mutex_lock (GMutex *mutex)
209 if G_UNLIKELY ((status = pthread_mutex_lock (g_mutex_get_impl (mutex))) != 0)
210 g_thread_abort (status, "pthread_mutex_lock");
217 * Unlocks @mutex. If another thread is blocked in a g_mutex_lock()
218 * call for @mutex, it will become unblocked and can lock @mutex itself.
220 * Calling g_mutex_unlock() on a mutex that is not locked by the
221 * current thread leads to undefined behaviour.
224 g_mutex_unlock (GMutex *mutex)
228 if G_UNLIKELY ((status = pthread_mutex_unlock (g_mutex_get_impl (mutex))) != 0)
229 g_thread_abort (status, "pthread_mutex_unlock");
236 * Tries to lock @mutex. If @mutex is already locked by another thread,
237 * it immediately returns %FALSE. Otherwise it locks @mutex and returns
240 * #GMutex is neither guaranteed to be recursive nor to be
241 * non-recursive. As such, calling g_mutex_lock() on a #GMutex that has
242 * already been locked by the same thread results in undefined behaviour
243 * (including but not limited to deadlocks or arbitrary return values).
245 * Returns: %TRUE if @mutex could be locked
248 g_mutex_trylock (GMutex *mutex)
252 if G_LIKELY ((status = pthread_mutex_trylock (g_mutex_get_impl (mutex))) == 0)
255 if G_UNLIKELY (status != EBUSY)
256 g_thread_abort (status, "pthread_mutex_trylock");
263 static pthread_mutex_t *
264 g_rec_mutex_impl_new (void)
266 pthread_mutexattr_t attr;
267 pthread_mutex_t *mutex;
269 mutex = malloc (sizeof (pthread_mutex_t));
270 if G_UNLIKELY (mutex == NULL)
271 g_thread_abort (errno, "malloc");
273 pthread_mutexattr_init (&attr);
274 pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
275 pthread_mutex_init (mutex, &attr);
276 pthread_mutexattr_destroy (&attr);
282 g_rec_mutex_impl_free (pthread_mutex_t *mutex)
284 pthread_mutex_destroy (mutex);
288 static pthread_mutex_t *
289 g_rec_mutex_get_impl (GRecMutex *rec_mutex)
291 pthread_mutex_t *impl = g_atomic_pointer_get (&rec_mutex->p);
293 if G_UNLIKELY (impl == NULL)
295 impl = g_rec_mutex_impl_new ();
296 if (!g_atomic_pointer_compare_and_exchange (&rec_mutex->p, NULL, impl))
297 g_rec_mutex_impl_free (impl);
306 * @rec_mutex: an uninitialized #GRecMutex
308 * Initializes a #GRecMutex so that it can be used.
310 * This function is useful to initialize a recursive mutex
311 * that has been allocated on the stack, or as part of a larger
314 * It is not necessary to initialise a recursive mutex that has been
315 * statically allocated.
317 * |[<!-- language="C" -->
325 * b = g_new (Blob, 1);
326 * g_rec_mutex_init (&b->m);
329 * Calling g_rec_mutex_init() on an already initialized #GRecMutex
330 * leads to undefined behaviour.
332 * To undo the effect of g_rec_mutex_init() when a recursive mutex
333 * is no longer needed, use g_rec_mutex_clear().
338 g_rec_mutex_init (GRecMutex *rec_mutex)
340 rec_mutex->p = g_rec_mutex_impl_new ();
345 * @rec_mutex: an initialized #GRecMutex
347 * Frees the resources allocated to a recursive mutex with
348 * g_rec_mutex_init().
350 * This function should not be used with a #GRecMutex that has been
351 * statically allocated.
353 * Calling g_rec_mutex_clear() on a locked recursive mutex leads
354 * to undefined behaviour.
359 g_rec_mutex_clear (GRecMutex *rec_mutex)
361 g_rec_mutex_impl_free (rec_mutex->p);
366 * @rec_mutex: a #GRecMutex
368 * Locks @rec_mutex. If @rec_mutex is already locked by another
369 * thread, the current thread will block until @rec_mutex is
370 * unlocked by the other thread. If @rec_mutex is already locked
371 * by the current thread, the 'lock count' of @rec_mutex is increased.
372 * The mutex will only become available again when it is unlocked
373 * as many times as it has been locked.
378 g_rec_mutex_lock (GRecMutex *mutex)
380 pthread_mutex_lock (g_rec_mutex_get_impl (mutex));
384 * g_rec_mutex_unlock:
385 * @rec_mutex: a #GRecMutex
387 * Unlocks @rec_mutex. If another thread is blocked in a
388 * g_rec_mutex_lock() call for @rec_mutex, it will become unblocked
389 * and can lock @rec_mutex itself.
391 * Calling g_rec_mutex_unlock() on a recursive mutex that is not
392 * locked by the current thread leads to undefined behaviour.
397 g_rec_mutex_unlock (GRecMutex *rec_mutex)
399 pthread_mutex_unlock (rec_mutex->p);
403 * g_rec_mutex_trylock:
404 * @rec_mutex: a #GRecMutex
406 * Tries to lock @rec_mutex. If @rec_mutex is already locked
407 * by another thread, it immediately returns %FALSE. Otherwise
408 * it locks @rec_mutex and returns %TRUE.
410 * Returns: %TRUE if @rec_mutex could be locked
415 g_rec_mutex_trylock (GRecMutex *rec_mutex)
417 if (pthread_mutex_trylock (g_rec_mutex_get_impl (rec_mutex)) != 0)
425 static pthread_rwlock_t *
426 g_rw_lock_impl_new (void)
428 pthread_rwlock_t *rwlock;
431 rwlock = malloc (sizeof (pthread_rwlock_t));
432 if G_UNLIKELY (rwlock == NULL)
433 g_thread_abort (errno, "malloc");
435 if G_UNLIKELY ((status = pthread_rwlock_init (rwlock, NULL)) != 0)
436 g_thread_abort (status, "pthread_rwlock_init");
442 g_rw_lock_impl_free (pthread_rwlock_t *rwlock)
444 pthread_rwlock_destroy (rwlock);
448 static pthread_rwlock_t *
449 g_rw_lock_get_impl (GRWLock *lock)
451 pthread_rwlock_t *impl = g_atomic_pointer_get (&lock->p);
453 if G_UNLIKELY (impl == NULL)
455 impl = g_rw_lock_impl_new ();
456 if (!g_atomic_pointer_compare_and_exchange (&lock->p, NULL, impl))
457 g_rw_lock_impl_free (impl);
466 * @rw_lock: an uninitialized #GRWLock
468 * Initializes a #GRWLock so that it can be used.
470 * This function is useful to initialize a lock that has been
471 * allocated on the stack, or as part of a larger structure. It is not
472 * necessary to initialise a reader-writer lock that has been statically
475 * |[<!-- language="C" -->
483 * b = g_new (Blob, 1);
484 * g_rw_lock_init (&b->l);
487 * To undo the effect of g_rw_lock_init() when a lock is no longer
488 * needed, use g_rw_lock_clear().
490 * Calling g_rw_lock_init() on an already initialized #GRWLock leads
491 * to undefined behaviour.
496 g_rw_lock_init (GRWLock *rw_lock)
498 rw_lock->p = g_rw_lock_impl_new ();
503 * @rw_lock: an initialized #GRWLock
505 * Frees the resources allocated to a lock with g_rw_lock_init().
507 * This function should not be used with a #GRWLock that has been
508 * statically allocated.
510 * Calling g_rw_lock_clear() when any thread holds the lock
511 * leads to undefined behaviour.
516 g_rw_lock_clear (GRWLock *rw_lock)
518 g_rw_lock_impl_free (rw_lock->p);
522 * g_rw_lock_writer_lock:
523 * @rw_lock: a #GRWLock
525 * Obtain a write lock on @rw_lock. If any thread already holds
526 * a read or write lock on @rw_lock, the current thread will block
527 * until all other threads have dropped their locks on @rw_lock.
532 g_rw_lock_writer_lock (GRWLock *rw_lock)
534 pthread_rwlock_wrlock (g_rw_lock_get_impl (rw_lock));
538 * g_rw_lock_writer_trylock:
539 * @rw_lock: a #GRWLock
541 * Tries to obtain a write lock on @rw_lock. If any other thread holds
542 * a read or write lock on @rw_lock, it immediately returns %FALSE.
543 * Otherwise it locks @rw_lock and returns %TRUE.
545 * Returns: %TRUE if @rw_lock could be locked
550 g_rw_lock_writer_trylock (GRWLock *rw_lock)
552 if (pthread_rwlock_trywrlock (g_rw_lock_get_impl (rw_lock)) != 0)
559 * g_rw_lock_writer_unlock:
560 * @rw_lock: a #GRWLock
562 * Release a write lock on @rw_lock.
564 * Calling g_rw_lock_writer_unlock() on a lock that is not held
565 * by the current thread leads to undefined behaviour.
570 g_rw_lock_writer_unlock (GRWLock *rw_lock)
572 pthread_rwlock_unlock (g_rw_lock_get_impl (rw_lock));
576 * g_rw_lock_reader_lock:
577 * @rw_lock: a #GRWLock
579 * Obtain a read lock on @rw_lock. If another thread currently holds
580 * the write lock on @rw_lock or blocks waiting for it, the current
581 * thread will block. Read locks can be taken recursively.
583 * It is implementation-defined how many threads are allowed to
584 * hold read locks on the same lock simultaneously.
589 g_rw_lock_reader_lock (GRWLock *rw_lock)
591 pthread_rwlock_rdlock (g_rw_lock_get_impl (rw_lock));
595 * g_rw_lock_reader_trylock:
596 * @rw_lock: a #GRWLock
598 * Tries to obtain a read lock on @rw_lock and returns %TRUE if
599 * the read lock was successfully obtained. Otherwise it
602 * Returns: %TRUE if @rw_lock could be locked
607 g_rw_lock_reader_trylock (GRWLock *rw_lock)
609 if (pthread_rwlock_tryrdlock (g_rw_lock_get_impl (rw_lock)) != 0)
616 * g_rw_lock_reader_unlock:
617 * @rw_lock: a #GRWLock
619 * Release a read lock on @rw_lock.
621 * Calling g_rw_lock_reader_unlock() on a lock that is not held
622 * by the current thread leads to undefined behaviour.
627 g_rw_lock_reader_unlock (GRWLock *rw_lock)
629 pthread_rwlock_unlock (g_rw_lock_get_impl (rw_lock));
634 static pthread_cond_t *
635 g_cond_impl_new (void)
637 pthread_condattr_t attr;
638 pthread_cond_t *cond;
641 pthread_condattr_init (&attr);
642 #if defined (HAVE_PTHREAD_CONDATTR_SETCLOCK) && defined (CLOCK_MONOTONIC)
643 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
646 cond = malloc (sizeof (pthread_cond_t));
647 if G_UNLIKELY (cond == NULL)
648 g_thread_abort (errno, "malloc");
650 if G_UNLIKELY ((status = pthread_cond_init (cond, &attr)) != 0)
651 g_thread_abort (status, "pthread_cond_init");
653 pthread_condattr_destroy (&attr);
659 g_cond_impl_free (pthread_cond_t *cond)
661 pthread_cond_destroy (cond);
665 static pthread_cond_t *
666 g_cond_get_impl (GCond *cond)
668 pthread_cond_t *impl = g_atomic_pointer_get (&cond->p);
670 if G_UNLIKELY (impl == NULL)
672 impl = g_cond_impl_new ();
673 if (!g_atomic_pointer_compare_and_exchange (&cond->p, NULL, impl))
674 g_cond_impl_free (impl);
683 * @cond: an uninitialized #GCond
685 * Initialises a #GCond so that it can be used.
687 * This function is useful to initialise a #GCond that has been
688 * allocated as part of a larger structure. It is not necessary to
689 * initialise a #GCond that has been statically allocated.
691 * To undo the effect of g_cond_init() when a #GCond is no longer
692 * needed, use g_cond_clear().
694 * Calling g_cond_init() on an already-initialised #GCond leads
695 * to undefined behaviour.
700 g_cond_init (GCond *cond)
702 cond->p = g_cond_impl_new ();
707 * @cond: an initialised #GCond
709 * Frees the resources allocated to a #GCond with g_cond_init().
711 * This function should not be used with a #GCond that has been
712 * statically allocated.
714 * Calling g_cond_clear() for a #GCond on which threads are
715 * blocking leads to undefined behaviour.
720 g_cond_clear (GCond *cond)
722 g_cond_impl_free (cond->p);
728 * @mutex: a #GMutex that is currently locked
730 * Atomically releases @mutex and waits until @cond is signalled.
731 * When this function returns, @mutex is locked again and owned by the
734 * When using condition variables, it is possible that a spurious wakeup
735 * may occur (ie: g_cond_wait() returns even though g_cond_signal() was
736 * not called). It's also possible that a stolen wakeup may occur.
737 * This is when g_cond_signal() is called, but another thread acquires
738 * @mutex before this thread and modifies the state of the program in
739 * such a way that when g_cond_wait() is able to return, the expected
740 * condition is no longer met.
742 * For this reason, g_cond_wait() must always be used in a loop. See
743 * the documentation for #GCond for a complete example.
746 g_cond_wait (GCond *cond,
751 if G_UNLIKELY ((status = pthread_cond_wait (g_cond_get_impl (cond), g_mutex_get_impl (mutex))) != 0)
752 g_thread_abort (status, "pthread_cond_wait");
759 * If threads are waiting for @cond, at least one of them is unblocked.
760 * If no threads are waiting for @cond, this function has no effect.
761 * It is good practice to hold the same lock as the waiting thread
762 * while calling this function, though not required.
765 g_cond_signal (GCond *cond)
769 if G_UNLIKELY ((status = pthread_cond_signal (g_cond_get_impl (cond))) != 0)
770 g_thread_abort (status, "pthread_cond_signal");
777 * If threads are waiting for @cond, all of them are unblocked.
778 * If no threads are waiting for @cond, this function has no effect.
779 * It is good practice to lock the same mutex as the waiting threads
780 * while calling this function, though not required.
783 g_cond_broadcast (GCond *cond)
787 if G_UNLIKELY ((status = pthread_cond_broadcast (g_cond_get_impl (cond))) != 0)
788 g_thread_abort (status, "pthread_cond_broadcast");
794 * @mutex: a #GMutex that is currently locked
795 * @end_time: the monotonic time to wait until
797 * Waits until either @cond is signalled or @end_time has passed.
799 * As with g_cond_wait() it is possible that a spurious or stolen wakeup
800 * could occur. For that reason, waiting on a condition variable should
801 * always be in a loop, based on an explicitly-checked predicate.
803 * %TRUE is returned if the condition variable was signalled (or in the
804 * case of a spurious wakeup). %FALSE is returned if @end_time has
807 * The following code shows how to correctly perform a timed wait on a
808 * condition variable (extending the example presented in the
809 * documentation for #GCond):
811 * |[<!-- language="C" -->
813 * pop_data_timed (void)
818 * g_mutex_lock (&data_mutex);
820 * end_time = g_get_monotonic_time () + 5 * G_TIME_SPAN_SECOND;
821 * while (!current_data)
822 * if (!g_cond_wait_until (&data_cond, &data_mutex, end_time))
824 * // timeout has passed.
825 * g_mutex_unlock (&data_mutex);
829 * // there is data for us
830 * data = current_data;
831 * current_data = NULL;
833 * g_mutex_unlock (&data_mutex);
839 * Notice that the end time is calculated once, before entering the
840 * loop and reused. This is the motivation behind the use of absolute
841 * time on this API -- if a relative time of 5 seconds were passed
842 * directly to the call and a spurious wakeup occurred, the program would
843 * have to start over waiting again (which would lead to a total wait
844 * time of more than 5 seconds).
846 * Returns: %TRUE on a signal, %FALSE on a timeout
850 g_cond_wait_until (GCond *cond,
857 #ifdef HAVE_PTHREAD_COND_TIMEDWAIT_RELATIVE_NP
858 /* end_time is given relative to the monotonic clock as returned by
859 * g_get_monotonic_time().
861 * Since this pthreads wants the relative time, convert it back again.
864 gint64 now = g_get_monotonic_time ();
870 relative = end_time - now;
872 ts.tv_sec = relative / 1000000;
873 ts.tv_nsec = (relative % 1000000) * 1000;
875 if ((status = pthread_cond_timedwait_relative_np (g_cond_get_impl (cond), g_mutex_get_impl (mutex), &ts)) == 0)
878 #elif defined (HAVE_PTHREAD_CONDATTR_SETCLOCK) && defined (CLOCK_MONOTONIC)
879 /* This is the exact check we used during init to set the clock to
880 * monotonic, so if we're in this branch, timedwait() will already be
881 * expecting a monotonic clock.
884 ts.tv_sec = end_time / 1000000;
885 ts.tv_nsec = (end_time % 1000000) * 1000;
887 if ((status = pthread_cond_timedwait (g_cond_get_impl (cond), g_mutex_get_impl (mutex), &ts)) == 0)
891 #error Cannot support GCond on your platform.
894 if G_UNLIKELY (status != ETIMEDOUT)
895 g_thread_abort (status, "pthread_cond_timedwait");
905 * The #GPrivate struct is an opaque data structure to represent a
906 * thread-local data key. It is approximately equivalent to the
907 * pthread_setspecific()/pthread_getspecific() APIs on POSIX and to
908 * TlsSetValue()/TlsGetValue() on Windows.
910 * If you don't already know why you might want this functionality,
911 * then you probably don't need it.
913 * #GPrivate is a very limited resource (as far as 128 per program,
914 * shared between all libraries). It is also not possible to destroy a
915 * #GPrivate after it has been used. As such, it is only ever acceptable
916 * to use #GPrivate in static scope, and even then sparingly so.
918 * See G_PRIVATE_INIT() for a couple of examples.
920 * The #GPrivate structure should be considered opaque. It should only
921 * be accessed via the g_private_ functions.
926 * @notify: a #GDestroyNotify
928 * A macro to assist with the static initialisation of a #GPrivate.
930 * This macro is useful for the case that a #GDestroyNotify function
931 * should be associated the key. This is needed when the key will be
932 * used to point at memory that should be deallocated when the thread
935 * Additionally, the #GDestroyNotify will also be called on the previous
936 * value stored in the key when g_private_replace() is used.
938 * If no #GDestroyNotify is needed, then use of this macro is not
939 * required -- if the #GPrivate is declared in static scope then it will
940 * be properly initialised by default (ie: to all zeros). See the
943 * |[<!-- language="C" -->
944 * static GPrivate name_key = G_PRIVATE_INIT (g_free);
946 * // return value should not be freed
948 * get_local_name (void)
950 * return g_private_get (&name_key);
954 * set_local_name (const gchar *name)
956 * g_private_replace (&name_key, g_strdup (name));
960 * static GPrivate count_key; // no free function
963 * get_local_count (void)
965 * return GPOINTER_TO_INT (g_private_get (&count_key));
969 * set_local_count (gint count)
971 * g_private_set (&count_key, GINT_TO_POINTER (count));
978 static pthread_key_t *
979 g_private_impl_new (GDestroyNotify notify)
984 key = malloc (sizeof (pthread_key_t));
985 if G_UNLIKELY (key == NULL)
986 g_thread_abort (errno, "malloc");
987 status = pthread_key_create (key, notify);
988 if G_UNLIKELY (status != 0)
989 g_thread_abort (status, "pthread_key_create");
995 g_private_impl_free (pthread_key_t *key)
999 status = pthread_key_delete (*key);
1000 if G_UNLIKELY (status != 0)
1001 g_thread_abort (status, "pthread_key_delete");
1005 static pthread_key_t *
1006 g_private_get_impl (GPrivate *key)
1008 pthread_key_t *impl = g_atomic_pointer_get (&key->p);
1010 if G_UNLIKELY (impl == NULL)
1012 impl = g_private_impl_new (key->notify);
1013 if (!g_atomic_pointer_compare_and_exchange (&key->p, NULL, impl))
1015 g_private_impl_free (impl);
1027 * Returns the current value of the thread local variable @key.
1029 * If the value has not yet been set in this thread, %NULL is returned.
1030 * Values are never copied between threads (when a new thread is
1031 * created, for example).
1033 * Returns: the thread-local value
1036 g_private_get (GPrivate *key)
1038 /* quote POSIX: No errors are returned from pthread_getspecific(). */
1039 return pthread_getspecific (*g_private_get_impl (key));
1045 * @value: the new value
1047 * Sets the thread local variable @key to have the value @value in the
1050 * This function differs from g_private_replace() in the following way:
1051 * the #GDestroyNotify for @key is not called on the old value.
1054 g_private_set (GPrivate *key,
1059 if G_UNLIKELY ((status = pthread_setspecific (*g_private_get_impl (key), value)) != 0)
1060 g_thread_abort (status, "pthread_setspecific");
1064 * g_private_replace:
1066 * @value: the new value
1068 * Sets the thread local variable @key to have the value @value in the
1071 * This function differs from g_private_set() in the following way: if
1072 * the previous value was non-%NULL then the #GDestroyNotify handler for
1073 * @key is run on it.
1078 g_private_replace (GPrivate *key,
1081 pthread_key_t *impl = g_private_get_impl (key);
1085 old = pthread_getspecific (*impl);
1086 if (old && key->notify)
1089 if G_UNLIKELY ((status = pthread_setspecific (*impl, value)) != 0)
1090 g_thread_abort (status, "pthread_setspecific");
1095 #define posix_check_err(err, name) G_STMT_START{ \
1096 int error = (err); \
1098 g_error ("file %s: line %d (%s): error '%s' during '%s'", \
1099 __FILE__, __LINE__, G_STRFUNC, \
1100 g_strerror (error), name); \
1103 #define posix_check_cmd(cmd) posix_check_err (cmd, #cmd)
1109 pthread_t system_thread;
1115 g_system_thread_free (GRealThread *thread)
1117 GThreadPosix *pt = (GThreadPosix *) thread;
1120 pthread_detach (pt->system_thread);
1122 g_mutex_clear (&pt->lock);
1124 g_slice_free (GThreadPosix, pt);
1128 g_system_thread_new (GThreadFunc thread_func,
1132 GThreadPosix *thread;
1133 pthread_attr_t attr;
1136 thread = g_slice_new0 (GThreadPosix);
1138 posix_check_cmd (pthread_attr_init (&attr));
1140 #ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
1143 #ifdef _SC_THREAD_STACK_MIN
1144 stack_size = MAX (sysconf (_SC_THREAD_STACK_MIN), stack_size);
1145 #endif /* _SC_THREAD_STACK_MIN */
1146 /* No error check here, because some systems can't do it and
1147 * we simply don't want threads to fail because of that. */
1148 pthread_attr_setstacksize (&attr, stack_size);
1150 #endif /* HAVE_PTHREAD_ATTR_SETSTACKSIZE */
1152 ret = pthread_create (&thread->system_thread, &attr, (void* (*)(void*))thread_func, thread);
1154 posix_check_cmd (pthread_attr_destroy (&attr));
1158 g_set_error (error, G_THREAD_ERROR, G_THREAD_ERROR_AGAIN,
1159 "Error creating thread: %s", g_strerror (ret));
1160 g_slice_free (GThreadPosix, thread);
1164 posix_check_err (ret, "pthread_create");
1166 g_mutex_init (&thread->lock);
1168 return (GRealThread *) thread;
1174 * Causes the calling thread to voluntarily relinquish the CPU, so
1175 * that other threads can run.
1177 * This function is often used as a method to make busy wait less evil.
1180 g_thread_yield (void)
1186 g_system_thread_wait (GRealThread *thread)
1188 GThreadPosix *pt = (GThreadPosix *) thread;
1190 g_mutex_lock (&pt->lock);
1194 posix_check_cmd (pthread_join (pt->system_thread, NULL));
1198 g_mutex_unlock (&pt->lock);
1202 g_system_thread_exit (void)
1204 pthread_exit (NULL);
1208 g_system_thread_set_name (const gchar *name)
1210 #ifdef HAVE_SYS_PRCTL_H
1212 prctl (PR_SET_NAME, name, 0, 0, 0, 0);
1218 /* vim:set foldmethod=marker: */