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, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
24 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
25 * file for a list of people on the GLib Team. See the ChangeLog
26 * files for a list of changes. These files are distributed with
27 * GLib at ftp://ftp.gtk.org/pub/gtk/.
30 /* The GMutex, GCond and GPrivate implementations in this file are some
31 * of the lowest-level code in GLib. All other parts of GLib (messages,
32 * memory, slices, etc) assume that they can freely use these facilities
33 * without risking recursion.
35 * As such, these functions are NOT permitted to call any other part of
38 * The thread manipulation functions (create, exit, join, etc.) have
39 * more freedom -- they can do as they please.
45 #include "gthreadprivate.h"
54 g_thread_abort (gint status,
55 const gchar *function)
57 fprintf (stderr, "GLib (gthread-posix.c): Unexpected error from C library during '%s': %s. Aborting.\n",
58 strerror (status), function);
66 * @mutex: an uninitialized #GMutex
68 * Initializes a #GMutex so that it can be used.
70 * This function is useful to initialize a mutex that has been
71 * allocated on the stack, or as part of a larger structure.
72 * It is not necessary to initialize a mutex that has been
73 * created with g_mutex_new(). Also see #G_MUTEX_INITIALIZER
74 * for an alternative way to initialize statically allocated mutexes.
84 * b = g_new (Blob, 1);
85 * g_mutex_init (&b->m);
89 * To undo the effect of g_mutex_init() when a mutex is no longer
90 * needed, use g_mutex_clear().
95 g_mutex_init (GMutex *mutex)
99 if G_UNLIKELY ((status = pthread_mutex_init (&mutex->impl, NULL)) != 0)
100 g_thread_abort (status, "pthread_mutex_init");
105 * @mutex: an initialized #GMutex
107 * Frees the resources allocated to a mutex with g_mutex_init().
109 * #GMutexes that have have been created with g_mutex_new() should
110 * be freed with g_mutex_free() instead.
115 g_mutex_clear (GMutex *mutex)
119 if G_UNLIKELY ((status = pthread_mutex_destroy (&mutex->impl)) != 0)
120 g_thread_abort (status, "pthread_mutex_destroy");
127 * Locks @mutex. If @mutex is already locked by another thread, the
128 * current thread will block until @mutex is unlocked by the other
131 * This function can be used even if g_thread_init() has not yet been
132 * called, and, in that case, will do nothing.
134 * <note>#GMutex is neither guaranteed to be recursive nor to be
135 * non-recursive, i.e. a thread could deadlock while calling
136 * g_mutex_lock(), if it already has locked @mutex. Use
137 * #GStaticRecMutex, if you need recursive mutexes.</note>
140 g_mutex_lock (GMutex *mutex)
144 if G_UNLIKELY ((status = pthread_mutex_lock (&mutex->impl)) != 0)
145 g_thread_abort (status, "pthread_mutex_lock");
152 * Unlocks @mutex. If another thread is blocked in a g_mutex_lock()
153 * call for @mutex, it will be woken and can lock @mutex itself.
155 * This function can be used even if g_thread_init() has not yet been
156 * called, and, in that case, will do nothing.
159 g_mutex_unlock (GMutex *mutex)
163 if G_UNLIKELY ((status = pthread_mutex_unlock (&mutex->impl)) != 0)
164 g_thread_abort (status, "pthread_mutex_lock");
171 * Tries to lock @mutex. If @mutex is already locked by another thread,
172 * it immediately returns %FALSE. Otherwise it locks @mutex and returns
175 * This function can be used even if g_thread_init() has not yet been
176 * called, and, in that case, will immediately return %TRUE.
178 * <note>#GMutex is neither guaranteed to be recursive nor to be
179 * non-recursive, i.e. the return value of g_mutex_trylock() could be
180 * both %FALSE or %TRUE, if the current thread already has locked
181 * @mutex. Use #GStaticRecMutex, if you need recursive
184 * Returns: %TRUE, if @mutex could be locked
187 g_mutex_trylock (GMutex *mutex)
191 if G_LIKELY ((status = pthread_mutex_trylock (&mutex->impl)) == 0)
194 if G_UNLIKELY (status != EBUSY)
195 g_thread_abort (status, "pthread_mutex_trylock");
204 * @cond: an uninitialized #GCond
206 * Initialized a #GCond so that it can be used.
208 * This function is useful to initialize a #GCond that has been
209 * allocated on the stack, or as part of a larger structure.
210 * It is not necessary to initialize a #GCond that has been
211 * created with g_cond_new(). Also see #G_COND_INITIALIZER
212 * for an alternative way to initialize statically allocated
218 g_cond_init (GCond *cond)
222 if G_UNLIKELY ((status = pthread_cond_init (&cond->impl, NULL)) != 0)
223 g_thread_abort (status, "pthread_cond_init");
228 * @cond: an initialized #GCond
230 * Frees the resources allocated ot a #GCond with g_cond_init().
232 * #GConds that have been created with g_cond_new() should
233 * be freed with g_cond_free() instead.
238 g_cond_clear (GCond *cond)
242 if G_UNLIKELY ((status = pthread_cond_destroy (&cond->impl)) != 0)
243 g_thread_abort (status, "pthread_cond_destroy");
249 * @mutex: a #GMutex that is currently locked
251 * Waits until this thread is woken up on @cond.
252 * The @mutex is unlocked before falling asleep
253 * and locked again before resuming.
255 * This function can be used even if g_thread_init() has not yet been
256 * called, and, in that case, will immediately return.
259 g_cond_wait (GCond *cond,
264 if G_UNLIKELY ((status = pthread_cond_wait (&cond->impl, &mutex->impl)) != 0)
265 g_thread_abort (status, "pthread_cond_wait");
272 * If threads are waiting for @cond, exactly one of them is woken up.
273 * It is good practice to hold the same lock as the waiting thread
274 * while calling this function, though not required.
276 * This function can be used even if g_thread_init() has not yet been
277 * called, and, in that case, will do nothing.
280 g_cond_signal (GCond *cond)
284 if G_UNLIKELY ((status = pthread_cond_signal (&cond->impl)) != 0)
285 g_thread_abort (status, "pthread_cond_signal");
292 * If threads are waiting for @cond, all of them are woken up.
293 * It is good practice to lock the same mutex as the waiting threads
294 * while calling this function, though not required.
296 * This function can be used even if g_thread_init() has not yet been
297 * called, and, in that case, will do nothing.
300 g_cond_broadcast (GCond *cond)
304 if G_UNLIKELY ((status = pthread_cond_broadcast (&cond->impl)) != 0)
305 g_thread_abort (status, "pthread_cond_broadcast");
311 * @mutex: a #GMutex that is currently locked
312 * @abs_time: a #GTimeVal, determining the final time
314 * Waits until this thread is woken up on @cond, but not longer than
315 * until the time specified by @abs_time. The @mutex is unlocked before
316 * falling asleep and locked again before resuming.
318 * If @abs_time is %NULL, g_cond_timed_wait() acts like g_cond_wait().
320 * This function can be used even if g_thread_init() has not yet been
321 * called, and, in that case, will immediately return %TRUE.
323 * To easily calculate @abs_time a combination of g_get_current_time()
324 * and g_time_val_add() can be used.
326 * Returns: %TRUE if @cond was signalled, or %FALSE on timeout
329 g_cond_timed_wait (GCond *cond,
333 struct timespec end_time;
336 if (abs_time == NULL)
338 g_cond_wait (cond, mutex);
342 end_time.tv_sec = abs_time->tv_sec;
343 end_time.tv_nsec = abs_time->tv_usec * 1000;
345 if ((status = pthread_cond_timedwait (&cond->impl, &mutex->impl, &end_time)) == 0)
348 if G_UNLIKELY (status != ETIMEDOUT)
349 g_thread_abort (status, "pthread_cond_timedwait");
357 * @mutex: a #GMutex that is currently locked
358 * @abs_time: the final time, in microseconds
360 * A variant of g_cond_timed_wait() that takes @abs_time
361 * as a #gint64 instead of a #GTimeVal.
362 * See g_cond_timed_wait() for details.
364 * Returns: %TRUE if @cond was signalled, or %FALSE on timeout
369 g_cond_timedwait (GCond *cond,
373 struct timespec end_time;
376 end_time.tv_sec = abs_time / 1000000;
377 end_time.tv_nsec = (abs_time % 1000000) * 1000;
379 if ((status = pthread_cond_timedwait (&cond->impl, &mutex->impl, &end_time)) == 0)
382 if G_UNLIKELY (status != ETIMEDOUT)
383 g_thread_abort (status, "pthread_cond_timedwait");
391 g_private_init (GPrivate *key,
392 GDestroyNotify notify)
394 pthread_key_create (&key->key, notify);
400 * @private_key: a #GPrivate
402 * Returns the pointer keyed to @private_key for the current thread. If
403 * g_private_set() hasn't been called for the current @private_key and
404 * thread yet, this pointer will be %NULL.
406 * This function can be used even if g_thread_init() has not yet been
407 * called, and, in that case, will return the value of @private_key
408 * casted to #gpointer. Note however, that private data set
409 * <emphasis>before</emphasis> g_thread_init() will
410 * <emphasis>not</emphasis> be retained <emphasis>after</emphasis> the
411 * call. Instead, %NULL will be returned in all threads directly after
412 * g_thread_init(), regardless of any g_private_set() calls issued
413 * before threading system initialization.
415 * Returns: the corresponding pointer
418 g_private_get (GPrivate *key)
421 return key->single_value;
423 /* quote POSIX: No errors are returned from pthread_getspecific(). */
424 return pthread_getspecific (key->key);
429 * @private_key: a #GPrivate
430 * @data: the new pointer
432 * Sets the pointer keyed to @private_key for the current thread.
434 * This function can be used even if g_thread_init() has not yet been
435 * called, and, in that case, will set @private_key to @data casted to
436 * #GPrivate*. See g_private_get() for resulting caveats.
439 g_private_set (GPrivate *key,
446 key->single_value = value;
450 if G_UNLIKELY ((status = pthread_setspecific (key->key, value)) != 0)
451 g_thread_abort (status, "pthread_setspecific");
457 #include "gthreadprivate.h"
462 #ifdef HAVE_SYS_TIME_H
463 # include <sys/time.h>
473 #define posix_check_err(err, name) G_STMT_START{ \
476 g_error ("file %s: line %d (%s): error '%s' during '%s'", \
477 __FILE__, __LINE__, G_STRFUNC, \
478 g_strerror (error), name); \
481 #define posix_check_cmd(cmd) posix_check_err (cmd, #cmd)
483 #ifdef G_ENABLE_DEBUG
484 static gboolean posix_check_cmd_prio_warned = FALSE;
485 # define posix_check_cmd_prio(cmd) G_STMT_START{ \
489 if (!posix_check_cmd_prio_warned) \
491 posix_check_cmd_prio_warned = TRUE; \
492 g_warning ("Priorities can only be changed " \
493 "(resp. increased) by root."); \
497 posix_check_err (err, #cmd); \
499 #else /* G_ENABLE_DEBUG */
500 # define posix_check_cmd_prio(cmd) G_STMT_START{ \
503 posix_check_err (err, #cmd); \
505 #endif /* G_ENABLE_DEBUG */
507 #if defined (POSIX_MIN_PRIORITY) && defined (POSIX_MAX_PRIORITY)
508 # define HAVE_PRIORITIES 1
509 static gint priority_normal_value;
511 /* FreeBSD threads use different priority values from the POSIX_
512 * defines so we just set them here. The corresponding macros
513 * PTHREAD_MIN_PRIORITY and PTHREAD_MAX_PRIORITY are implied to be
514 * exported by the docs, but they aren't.
516 # define PRIORITY_LOW_VALUE 0
517 # define PRIORITY_URGENT_VALUE 31
518 # else /* !__FreeBSD__ */
519 # define PRIORITY_LOW_VALUE POSIX_MIN_PRIORITY
520 # define PRIORITY_URGENT_VALUE POSIX_MAX_PRIORITY
521 # endif /* !__FreeBSD__ */
522 # define PRIORITY_NORMAL_VALUE priority_normal_value
524 # define PRIORITY_HIGH_VALUE \
525 ((PRIORITY_NORMAL_VALUE + PRIORITY_URGENT_VALUE * 2) / 3)
528 g_thread_priority_map (GThreadPriority priority)
532 case G_THREAD_PRIORITY_LOW:
533 return PRIORITY_LOW_VALUE;
535 case G_THREAD_PRIORITY_NORMAL:
536 return PRIORITY_NORMAL_VALUE;
538 case G_THREAD_PRIORITY_HIGH:
539 return PRIORITY_HIGH_VALUE;
541 case G_THREAD_PRIORITY_URGENT:
542 return PRIORITY_URGENT_VALUE;
545 g_assert_not_reached ();
549 #endif /* POSIX_MIN_PRIORITY && POSIX_MAX_PRIORITY */
551 static gulong g_thread_min_stack_size = 0;
553 #define G_MUTEX_SIZE (sizeof (pthread_mutex_t))
556 _g_thread_impl_init(void)
558 #ifdef _SC_THREAD_STACK_MIN
559 g_thread_min_stack_size = MAX (sysconf (_SC_THREAD_STACK_MIN), 0);
560 #endif /* _SC_THREAD_STACK_MIN */
561 #ifdef HAVE_PRIORITIES
563 struct sched_param sched;
565 posix_check_cmd (pthread_getschedparam (pthread_self(), &policy, &sched));
566 priority_normal_value = sched.sched_priority;
568 #endif /* HAVE_PRIORITIES */
572 g_thread_create_posix_impl (GThreadFunc thread_func,
577 GThreadPriority priority,
584 g_return_if_fail (thread_func);
585 g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
586 g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
588 posix_check_cmd (pthread_attr_init (&attr));
590 #ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
593 stack_size = MAX (g_thread_min_stack_size, stack_size);
594 /* No error check here, because some systems can't do it and
595 * we simply don't want threads to fail because of that. */
596 pthread_attr_setstacksize (&attr, stack_size);
598 #endif /* HAVE_PTHREAD_ATTR_SETSTACKSIZE */
600 #ifdef PTHREAD_SCOPE_SYSTEM
602 /* No error check here, because some systems can't do it and we
603 * simply don't want threads to fail because of that. */
604 pthread_attr_setscope (&attr, PTHREAD_SCOPE_SYSTEM);
605 #endif /* PTHREAD_SCOPE_SYSTEM */
607 posix_check_cmd (pthread_attr_setdetachstate (&attr,
608 joinable ? PTHREAD_CREATE_JOINABLE : PTHREAD_CREATE_DETACHED));
610 #ifdef HAVE_PRIORITIES
612 struct sched_param sched;
613 posix_check_cmd (pthread_attr_getschedparam (&attr, &sched));
614 sched.sched_priority = g_thread_priority_map (priority);
615 posix_check_cmd_prio (pthread_attr_setschedparam (&attr, &sched));
617 #endif /* HAVE_PRIORITIES */
618 ret = pthread_create (thread, &attr, (void* (*)(void*))thread_func, arg);
620 posix_check_cmd (pthread_attr_destroy (&attr));
624 g_set_error (error, G_THREAD_ERROR, G_THREAD_ERROR_AGAIN,
625 "Error creating thread: %s", g_strerror (ret));
629 posix_check_err (ret, "pthread_create");
635 * Gives way to other threads waiting to be scheduled.
637 * This function is often used as a method to make busy wait less evil.
638 * But in most cases you will encounter, there are better methods to do
639 * that. So in general you shouldn't use this function.
642 g_thread_yield (void)
648 g_thread_join_posix_impl (gpointer thread)
651 posix_check_cmd (pthread_join (*(pthread_t*)thread, &ignore));
655 g_system_thread_exit (void)
661 g_thread_set_priority_posix_impl (gpointer thread, GThreadPriority priority)
663 g_return_if_fail (priority >= G_THREAD_PRIORITY_LOW);
664 g_return_if_fail (priority <= G_THREAD_PRIORITY_URGENT);
665 #ifdef HAVE_PRIORITIES
667 struct sched_param sched;
669 posix_check_cmd (pthread_getschedparam (*(pthread_t*)thread, &policy,
671 sched.sched_priority = g_thread_priority_map (priority);
672 posix_check_cmd_prio (pthread_setschedparam (*(pthread_t*)thread, policy,
675 #endif /* HAVE_PRIORITIES */
679 g_thread_self_posix_impl (gpointer thread)
681 *(pthread_t*)thread = pthread_self();
685 g_system_thread_equal (gpointer thread1,
688 return (pthread_equal (*(pthread_t*)thread1, *(pthread_t*)thread2) != 0);
692 GThreadFunctions g_thread_functions_for_glib_use =
708 g_thread_create_posix_impl,
710 g_thread_join_posix_impl,
711 g_system_thread_exit,
712 g_thread_set_priority_posix_impl,
713 g_thread_self_posix_impl,
714 g_system_thread_equal,
717 /* vim:set foldmethod=marker: */