1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
4 * gthread.c: MT safety related functions
5 * Copyright 1998 Sebastian Wilhelmi; University of Karlsruhe
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with this library; if not, write to the
20 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
21 * Boston, MA 02111-1307, USA.
26 /* we know we are deprecated here, no need for warnings */
27 #define GLIB_DISABLE_DEPRECATION_WARNINGS
29 #include "gmessages.h"
33 #include "gthreadprivate.h"
34 #include "deprecated/gthread.h"
38 /* {{{1 Documentation */
41 * SECTION:threads-deprecated
42 * @title: Deprecated thread API
43 * @short_description: old thread APIs (for reference only)
46 * These APIs are deprecated. You should not use them in new code.
47 * This section remains only to assist with understanding code that was
48 * written to use these APIs at some point in the past.
53 * @G_THREAD_PRIORITY_LOW: a priority lower than normal
54 * @G_THREAD_PRIORITY_NORMAL: the default priority
55 * @G_THREAD_PRIORITY_HIGH: a priority higher than normal
56 * @G_THREAD_PRIORITY_URGENT: the highest priority
58 * Deprecated:2.32: Thread priorities no longer have any effect.
63 * @mutex_new: virtual function pointer for g_mutex_new()
64 * @mutex_lock: virtual function pointer for g_mutex_lock()
65 * @mutex_trylock: virtual function pointer for g_mutex_trylock()
66 * @mutex_unlock: virtual function pointer for g_mutex_unlock()
67 * @mutex_free: virtual function pointer for g_mutex_free()
68 * @cond_new: virtual function pointer for g_cond_new()
69 * @cond_signal: virtual function pointer for g_cond_signal()
70 * @cond_broadcast: virtual function pointer for g_cond_broadcast()
71 * @cond_wait: virtual function pointer for g_cond_wait()
72 * @cond_timed_wait: virtual function pointer for g_cond_timed_wait()
73 * @cond_free: virtual function pointer for g_cond_free()
74 * @private_new: virtual function pointer for g_private_new()
75 * @private_get: virtual function pointer for g_private_get()
76 * @private_set: virtual function pointer for g_private_set()
77 * @thread_create: virtual function pointer for g_thread_create()
78 * @thread_yield: virtual function pointer for g_thread_yield()
79 * @thread_join: virtual function pointer for g_thread_join()
80 * @thread_exit: virtual function pointer for g_thread_exit()
81 * @thread_set_priority: virtual function pointer for
82 * g_thread_set_priority()
83 * @thread_self: virtual function pointer for g_thread_self()
84 * @thread_equal: used internally by recursive mutex locks and by some
87 * This function table is no longer used by g_thread_init()
88 * to initialize the thread system.
92 * G_THREADS_IMPL_POSIX:
94 * This macro is defined if POSIX style threads are used.
96 * Deprecated:2.32:POSIX threads are in use on all non-Windows systems.
97 * Use G_OS_WIN32 to detect Windows.
101 * G_THREADS_IMPL_WIN32:
103 * This macro is defined if Windows style threads are used.
105 * Deprecated:2.32:Use G_OS_WIN32 to detect Windows.
109 /* {{{1 Exported Variables */
111 /* Set this FALSE to have previously-compiled GStaticMutex code use the
112 * slow path (ie: call into us) to avoid compatibility problems.
114 gboolean g_thread_use_default_impl = FALSE;
116 GThreadFunctions g_thread_functions_for_glib_use =
144 return g_get_monotonic_time () * 1000;
147 guint64 (*g_thread_gettime) (void) = gettime;
149 /* Initialisation {{{1 ---------------------------------------------------- */
150 gboolean g_threads_got_initialized = TRUE;
154 * @vtable: a function table of type #GThreadFunctions, that provides
155 * the entry points to the thread system to be used. Since 2.32,
156 * this parameter is ignored and should always be %NULL
158 * If you use GLib from more than one thread, you must initialize the
159 * thread system by calling g_thread_init().
161 * Since version 2.24, calling g_thread_init() multiple times is allowed,
162 * but nothing happens except for the first call.
164 * Since version 2.32, GLib does not support custom thread implementations
165 * anymore and the @vtable parameter is ignored and you should pass %NULL.
167 * <note><para>g_thread_init() must not be called directly or indirectly
168 * in a callback from GLib. Also no mutexes may be currently locked while
169 * calling g_thread_init().</para></note>
171 * <note><para>To use g_thread_init() in your program, you have to link
172 * with the libraries that the command <command>pkg-config --libs
173 * gthread-2.0</command> outputs. This is not the case for all the
174 * other thread-related functions of GLib. Those can be used without
175 * having to link with the thread libraries.</para></note>
179 * g_thread_get_initialized:
181 * Indicates if g_thread_init() has been called.
183 * Returns: %TRUE if threads have been initialized.
188 g_thread_get_initialized (void)
190 return g_thread_supported ();
193 /* We need this for ABI compatibility */
194 void g_thread_init_glib (void) { }
196 /* Internal variables {{{1 */
198 static GSList *g_thread_all_threads = NULL;
199 static GSList *g_thread_free_indices = NULL;
201 /* Protects g_thread_all_threads and g_thread_free_indices */
202 G_LOCK_DEFINE_STATIC (g_static_mutex);
203 G_LOCK_DEFINE_STATIC (g_thread);
205 /* Misc. GThread functions {{{1 */
208 * g_thread_set_priority:
209 * @thread: a #GThread.
212 * This function does nothing.
214 * Deprecated:2.32: Thread priorities no longer have any effect.
217 g_thread_set_priority (GThread *thread,
218 GThreadPriority priority)
224 * @thread_func: function to call for all #GThread structures
225 * @user_data: second argument to @thread_func
227 * Call @thread_func on all #GThreads that have been
228 * created with g_thread_create().
230 * Note that threads may decide to exit while @thread_func is
231 * running, so without intimate knowledge about the lifetime of
232 * foreign threads, @thread_func shouldn't access the GThread*
233 * pointer passed in as first argument. However, @thread_func will
234 * not be called for threads which are known to have exited already.
236 * Due to thread lifetime checks, this function has an execution complexity
237 * which is quadratic in the number of existing threads.
241 * Deprecated:2.32: There aren't many things you can do with a #GThread,
242 * except comparing it with one that was returned from g_thread_create().
243 * There are better ways to find out if your thread is still alive.
246 g_thread_foreach (GFunc thread_func,
249 GSList *slist = NULL;
251 g_return_if_fail (thread_func != NULL);
252 /* snapshot the list of threads for iteration */
254 slist = g_slist_copy (g_thread_all_threads);
256 /* walk the list, skipping non-existent threads */
259 GSList *node = slist;
261 /* check whether the current thread still exists */
263 if (g_slist_find (g_thread_all_threads, node->data))
269 thread_func (thread, user_data);
270 g_slist_free_1 (node);
275 g_enumerable_thread_remove (gpointer data)
277 GRealThread *thread = data;
280 g_thread_all_threads = g_slist_remove (g_thread_all_threads, thread);
284 GPrivate enumerable_thread_private = G_PRIVATE_INIT (g_enumerable_thread_remove);
287 g_enumerable_thread_add (GRealThread *thread)
290 g_thread_all_threads = g_slist_prepend (g_thread_all_threads, thread);
293 g_private_set (&enumerable_thread_private, thread);
297 g_deprecated_thread_proxy (gpointer data)
299 GRealThread *real = data;
301 g_enumerable_thread_add (real);
303 return g_thread_proxy (data);
308 * @func: a function to execute in the new thread
309 * @data: an argument to supply to the new thread
310 * @joinable: should this thread be joinable?
311 * @error: return location for error, or %NULL
313 * This function creates a new thread.
315 * If @joinable is %TRUE, you can wait for this threads termination
316 * calling g_thread_join(). Otherwise the thread will just disappear
317 * when it terminates.
319 * The new thread executes the function @func with the argument @data.
320 * If the thread was created successfully, it is returned.
322 * @error can be %NULL to ignore errors, or non-%NULL to report errors.
323 * The error is set, if and only if the function returns %NULL.
325 * Returns: the new #GThread on success
327 * Deprecated:2.32: Use g_thread_new() instead
330 g_thread_create (GThreadFunc func,
335 return g_thread_new_internal (NULL, g_deprecated_thread_proxy, func, data, joinable, 0, error);
339 * g_thread_create_full:
340 * @func: a function to execute in the new thread.
341 * @data: an argument to supply to the new thread.
342 * @stack_size: a stack size for the new thread.
343 * @joinable: should this thread be joinable?
346 * @error: return location for error.
347 * @Returns: the new #GThread on success.
349 * This function creates a new thread.
351 * Deprecated:2.32: The @bound and @priority arguments are now ignored.
352 * Use g_thread_new() or g_thread_new_full() instead.
355 g_thread_create_full (GThreadFunc func,
360 GThreadPriority priority,
363 return g_thread_new_internal (NULL, g_deprecated_thread_proxy, func, data, joinable, stack_size, error);
368 /* GOnce {{{1 ------------------------------------------------------------- */
370 g_once_init_enter_impl (volatile gsize *location)
372 return (g_once_init_enter) (location);
375 /* GStaticMutex {{{1 ------------------------------------------------------ */
380 * A #GStaticMutex works like a #GMutex.
382 * Prior to GLib 2.32, GStaticMutex had the significant advantage
383 * that it doesn't need to be created at run-time, but can be defined
384 * at compile-time. Since 2.32, #GMutex can be statically allocated
385 * as well, and GStaticMutex has been deprecated.
387 * Here is a version of our give_me_next_number() example using
392 * Using <structname>GStaticMutex</structname>
393 * to simplify thread-safe programming
397 * give_me_next_number (void)
399 * static int current_number = 0;
401 * static GStaticMutex mutex = G_STATIC_MUTEX_INIT;
403 * g_static_mutex_lock (&mutex);
404 * ret_val = current_number = calc_next_number (current_number);
405 * g_static_mutex_unlock (&mutex);
412 * Sometimes you would like to dynamically create a mutex. If you don't
413 * want to require prior calling to g_thread_init(), because your code
414 * should also be usable in non-threaded programs, you are not able to
415 * use g_mutex_new() and thus #GMutex, as that requires a prior call to
416 * g_thread_init(). In theses cases you can also use a #GStaticMutex.
417 * It must be initialized with g_static_mutex_init() before using it
418 * and freed with with g_static_mutex_free() when not needed anymore to
419 * free up any allocated resources.
421 * Even though #GStaticMutex is not opaque, it should only be used with
422 * the following functions, as it is defined differently on different
425 * All of the <function>g_static_mutex_*</function> functions apart
426 * from <function>g_static_mutex_get_mutex</function> can also be used
427 * even if g_thread_init() has not yet been called. Then they do
428 * nothing, apart from <function>g_static_mutex_trylock</function>,
429 * which does nothing but returning %TRUE.
431 * <note><para>All of the <function>g_static_mutex_*</function>
432 * functions are actually macros. Apart from taking their addresses, you
433 * can however use them as if they were functions.</para></note>
437 * G_STATIC_MUTEX_INIT:
439 * A #GStaticMutex must be initialized with this macro, before it can
440 * be used. This macro can used be to initialize a variable, but it
441 * cannot be assigned to a variable. In that case you have to use
442 * g_static_mutex_init().
445 * GStaticMutex my_mutex = G_STATIC_MUTEX_INIT;
450 * g_static_mutex_init:
451 * @mutex: a #GStaticMutex to be initialized.
453 * Initializes @mutex.
454 * Alternatively you can initialize it with #G_STATIC_MUTEX_INIT.
456 * Deprecated: 2.32: Use g_mutex_init()
459 g_static_mutex_init (GStaticMutex *mutex)
461 static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
463 g_return_if_fail (mutex);
468 /* IMPLEMENTATION NOTE:
470 * On some platforms a GStaticMutex is actually a normal GMutex stored
471 * inside of a structure instead of being allocated dynamically. We can
472 * only do this for platforms on which we know, in advance, how to
473 * allocate (size) and initialise (value) that memory.
475 * On other platforms, a GStaticMutex is nothing more than a pointer to
476 * a GMutex. In that case, the first access we make to the static mutex
477 * must first allocate the normal GMutex and store it into the pointer.
479 * configure.ac writes macros into glibconfig.h to determine if
480 * g_static_mutex_get_mutex() accesses the structure in memory directly
481 * (on platforms where we are able to do that) or if it ends up here,
482 * where we may have to allocate the GMutex before returning it.
486 * g_static_mutex_get_mutex:
487 * @mutex: a #GStaticMutex.
488 * @Returns: the #GMutex corresponding to @mutex.
490 * For some operations (like g_cond_wait()) you must have a #GMutex
491 * instead of a #GStaticMutex. This function will return the
492 * corresponding #GMutex for @mutex.
494 * Deprecated: 2.32: Just use a #GMutex
497 g_static_mutex_get_mutex_impl (GStaticMutex* mutex)
501 if (!g_thread_supported ())
504 result = g_atomic_pointer_get (&mutex->mutex);
508 G_LOCK (g_static_mutex);
510 result = mutex->mutex;
513 result = g_mutex_new ();
514 g_atomic_pointer_set (&mutex->mutex, result);
517 G_UNLOCK (g_static_mutex);
523 /* IMPLEMENTATION NOTE:
525 * g_static_mutex_lock(), g_static_mutex_trylock() and
526 * g_static_mutex_unlock() are all preprocessor macros that wrap the
527 * corresponding g_mutex_*() function around a call to
528 * g_static_mutex_get_mutex().
532 * g_static_mutex_lock:
533 * @mutex: a #GStaticMutex.
535 * Works like g_mutex_lock(), but for a #GStaticMutex.
537 * Deprecated: 2.32: Use g_mutex_lock()
541 * g_static_mutex_trylock:
542 * @mutex: a #GStaticMutex.
543 * @Returns: %TRUE, if the #GStaticMutex could be locked.
545 * Works like g_mutex_trylock(), but for a #GStaticMutex.
547 * Deprecated: 2.32: Use g_mutex_trylock()
551 * g_static_mutex_unlock:
552 * @mutex: a #GStaticMutex.
554 * Works like g_mutex_unlock(), but for a #GStaticMutex.
556 * Deprecated: 2.32: Use g_mutex_unlock()
560 * g_static_mutex_free:
561 * @mutex: a #GStaticMutex to be freed.
563 * Releases all resources allocated to @mutex.
565 * You don't have to call this functions for a #GStaticMutex with an
566 * unbounded lifetime, i.e. objects declared 'static', but if you have
567 * a #GStaticMutex as a member of a structure and the structure is
568 * freed, you should also free the #GStaticMutex.
570 * <note><para>Calling g_static_mutex_free() on a locked mutex may
571 * result in undefined behaviour.</para></note>
573 * Deprecated: 2.32: Use g_mutex_free()
576 g_static_mutex_free (GStaticMutex* mutex)
578 GMutex **runtime_mutex;
580 g_return_if_fail (mutex);
582 /* The runtime_mutex is the first (or only) member of GStaticMutex,
583 * see both versions (of glibconfig.h) in configure.ac. Note, that
584 * this variable is NULL, if g_thread_init() hasn't been called or
585 * if we're using the default thread implementation and it provides
587 runtime_mutex = ((GMutex**)mutex);
590 g_mutex_free (*runtime_mutex);
592 *runtime_mutex = NULL;
595 /* {{{1 GStaticRecMutex */
600 * A #GStaticRecMutex works like a #GStaticMutex, but it can be locked
601 * multiple times by one thread. If you enter it n times, you have to
602 * unlock it n times again to let other threads lock it. An exception
603 * is the function g_static_rec_mutex_unlock_full(): that allows you to
604 * unlock a #GStaticRecMutex completely returning the depth, (i.e. the
605 * number of times this mutex was locked). The depth can later be used
606 * to restore the state of the #GStaticRecMutex by calling
607 * g_static_rec_mutex_lock_full(). In GLib 2.32, #GStaticRecMutex has
608 * been deprecated in favor of #GRecMutex.
610 * Even though #GStaticRecMutex is not opaque, it should only be used
611 * with the following functions.
613 * All of the <function>g_static_rec_mutex_*</function> functions can
614 * be used even if g_thread_init() has not been called. Then they do
615 * nothing, apart from <function>g_static_rec_mutex_trylock</function>,
616 * which does nothing but returning %TRUE.
620 * G_STATIC_REC_MUTEX_INIT:
622 * A #GStaticRecMutex must be initialized with this macro before it can
623 * be used. This macro can used be to initialize a variable, but it
624 * cannot be assigned to a variable. In that case you have to use
625 * g_static_rec_mutex_init().
628 * GStaticRecMutex my_mutex = G_STATIC_REC_MUTEX_INIT;
633 * g_static_rec_mutex_init:
634 * @mutex: a #GStaticRecMutex to be initialized.
636 * A #GStaticRecMutex must be initialized with this function before it
637 * can be used. Alternatively you can initialize it with
638 * #G_STATIC_REC_MUTEX_INIT.
640 * Deprecated: 2.32: Use g_rec_mutex_init()
643 g_static_rec_mutex_init (GStaticRecMutex *mutex)
645 static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
647 g_return_if_fail (mutex);
653 g_static_rec_mutex_get_rec_mutex_impl (GStaticRecMutex* mutex)
657 if (!g_thread_supported ())
660 result = g_atomic_pointer_get (&mutex->mutex.mutex);
664 G_LOCK (g_static_mutex);
666 result = (GRecMutex *) mutex->mutex.mutex;
669 result = g_slice_new (GRecMutex);
670 g_rec_mutex_init (result);
671 g_atomic_pointer_set (&mutex->mutex.mutex, result);
674 G_UNLOCK (g_static_mutex);
681 * g_static_rec_mutex_lock:
682 * @mutex: a #GStaticRecMutex to lock.
684 * Locks @mutex. If @mutex is already locked by another thread, the
685 * current thread will block until @mutex is unlocked by the other
686 * thread. If @mutex is already locked by the calling thread, this
687 * functions increases the depth of @mutex and returns immediately.
689 * Deprecated: 2.32: Use g_rec_mutex_lock()
692 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
695 rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
696 g_rec_mutex_lock (rm);
701 * g_static_rec_mutex_trylock:
702 * @mutex: a #GStaticRecMutex to lock.
703 * @Returns: %TRUE, if @mutex could be locked.
705 * Tries to lock @mutex. If @mutex is already locked by another thread,
706 * it immediately returns %FALSE. Otherwise it locks @mutex and returns
707 * %TRUE. If @mutex is already locked by the calling thread, this
708 * functions increases the depth of @mutex and immediately returns
711 * Deprecated: 2.32: Use g_rec_mutex_trylock()
714 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
717 rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
719 if (g_rec_mutex_trylock (rm))
729 * g_static_rec_mutex_unlock:
730 * @mutex: a #GStaticRecMutex to unlock.
732 * Unlocks @mutex. Another thread will be allowed to lock @mutex only
733 * when it has been unlocked as many times as it had been locked
734 * before. If @mutex is completely unlocked and another thread is
735 * blocked in a g_static_rec_mutex_lock() call for @mutex, it will be
736 * woken and can lock @mutex itself.
738 * Deprecated: 2.32: Use g_rec_mutex_unlock()
741 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
744 rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
746 g_rec_mutex_unlock (rm);
750 * g_static_rec_mutex_lock_full:
751 * @mutex: a #GStaticRecMutex to lock.
752 * @depth: number of times this mutex has to be unlocked to be
753 * completely unlocked.
755 * Works like calling g_static_rec_mutex_lock() for @mutex @depth times.
757 * Deprecated: 2.32: Use g_rec_mutex_lock()
760 g_static_rec_mutex_lock_full (GStaticRecMutex *mutex,
765 rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
768 g_rec_mutex_lock (rm);
774 * g_static_rec_mutex_unlock_full:
775 * @mutex: a #GStaticRecMutex to completely unlock.
776 * @Returns: number of times @mutex has been locked by the current
779 * Completely unlocks @mutex. If another thread is blocked in a
780 * g_static_rec_mutex_lock() call for @mutex, it will be woken and can
781 * lock @mutex itself. This function returns the number of times that
782 * @mutex has been locked by the current thread. To restore the state
783 * before the call to g_static_rec_mutex_unlock_full() you can call
784 * g_static_rec_mutex_lock_full() with the depth returned by this
787 * Deprecated: 2.32: Use g_rec_mutex_unlock()
790 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
795 rm = g_static_rec_mutex_get_rec_mutex_impl (mutex);
796 depth = mutex->depth;
797 while (mutex->depth--)
798 g_rec_mutex_unlock (rm);
804 * g_static_rec_mutex_free:
805 * @mutex: a #GStaticRecMutex to be freed.
807 * Releases all resources allocated to a #GStaticRecMutex.
809 * You don't have to call this functions for a #GStaticRecMutex with an
810 * unbounded lifetime, i.e. objects declared 'static', but if you have
811 * a #GStaticRecMutex as a member of a structure and the structure is
812 * freed, you should also free the #GStaticRecMutex.
814 * Deprecated: 2.32: Use g_rec_mutex_clear()
817 g_static_rec_mutex_free (GStaticRecMutex *mutex)
819 g_return_if_fail (mutex);
821 if (mutex->mutex.mutex)
823 GRecMutex *rm = (GRecMutex *) mutex->mutex.mutex;
825 g_rec_mutex_clear (rm);
826 g_slice_free (GRecMutex, rm);
830 /* GStaticRWLock {{{1 ----------------------------------------------------- */
835 * The #GStaticRWLock struct represents a read-write lock. A read-write
836 * lock can be used for protecting data that some portions of code only
837 * read from, while others also write. In such situations it is
838 * desirable that several readers can read at once, whereas of course
839 * only one writer may write at a time. Take a look at the following
843 * <title>An array with access functions</title>
845 * GStaticRWLock rwlock = G_STATIC_RW_LOCK_INIT;
849 * my_array_get (guint index)
851 * gpointer retval = NULL;
856 * g_static_rw_lock_reader_lock (&rwlock);
857 * if (index < array->len)
858 * retval = g_ptr_array_index (array, index);
859 * g_static_rw_lock_reader_unlock (&rwlock);
865 * my_array_set (guint index, gpointer data)
867 * g_static_rw_lock_writer_lock (&rwlock);
870 * array = g_ptr_array_new (<!-- -->);
872 * if (index >= array->len)
873 * g_ptr_array_set_size (array, index+1);
874 * g_ptr_array_index (array, index) = data;
876 * g_static_rw_lock_writer_unlock (&rwlock);
881 * This example shows an array which can be accessed by many readers
882 * (the <function>my_array_get()</function> function) simultaneously,
883 * whereas the writers (the <function>my_array_set()</function>
884 * function) will only be allowed once at a time and only if no readers
885 * currently access the array. This is because of the potentially
886 * dangerous resizing of the array. Using these functions is fully
887 * multi-thread safe now.
889 * Most of the time, writers should have precedence over readers. That
890 * means, for this implementation, that as soon as a writer wants to
891 * lock the data, no other reader is allowed to lock the data, whereas,
892 * of course, the readers that already have locked the data are allowed
893 * to finish their operation. As soon as the last reader unlocks the
894 * data, the writer will lock it.
896 * Even though #GStaticRWLock is not opaque, it should only be used
897 * with the following functions.
899 * All of the <function>g_static_rw_lock_*</function> functions can be
900 * used even if g_thread_init() has not been called. Then they do
901 * nothing, apart from <function>g_static_rw_lock_*_trylock</function>,
902 * which does nothing but returning %TRUE.
904 * <note><para>A read-write lock has a higher overhead than a mutex. For
905 * example, both g_static_rw_lock_reader_lock() and
906 * g_static_rw_lock_reader_unlock() have to lock and unlock a
907 * #GStaticMutex, so it takes at least twice the time to lock and unlock
908 * a #GStaticRWLock that it does to lock and unlock a #GStaticMutex. So
909 * only data structures that are accessed by multiple readers, and which
910 * keep the lock for a considerable time justify a #GStaticRWLock. The
911 * above example most probably would fare better with a
912 * #GStaticMutex.</para></note>
914 * Deprecated: 2.32: Use a #GRWLock instead
918 * G_STATIC_RW_LOCK_INIT:
920 * A #GStaticRWLock must be initialized with this macro before it can
921 * be used. This macro can used be to initialize a variable, but it
922 * cannot be assigned to a variable. In that case you have to use
923 * g_static_rw_lock_init().
926 * GStaticRWLock my_lock = G_STATIC_RW_LOCK_INIT;
931 * g_static_rw_lock_init:
932 * @lock: a #GStaticRWLock to be initialized.
934 * A #GStaticRWLock must be initialized with this function before it
935 * can be used. Alternatively you can initialize it with
936 * #G_STATIC_RW_LOCK_INIT.
938 * Deprecated: 2.32: Use g_rw_lock_init() instead
941 g_static_rw_lock_init (GStaticRWLock* lock)
943 static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
945 g_return_if_fail (lock);
951 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
954 *cond = g_cond_new ();
955 g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
959 g_static_rw_lock_signal (GStaticRWLock* lock)
961 if (lock->want_to_write && lock->write_cond)
962 g_cond_signal (lock->write_cond);
963 else if (lock->want_to_read && lock->read_cond)
964 g_cond_broadcast (lock->read_cond);
968 * g_static_rw_lock_reader_lock:
969 * @lock: a #GStaticRWLock to lock for reading.
971 * Locks @lock for reading. There may be unlimited concurrent locks for
972 * reading of a #GStaticRWLock at the same time. If @lock is already
973 * locked for writing by another thread or if another thread is already
974 * waiting to lock @lock for writing, this function will block until
975 * @lock is unlocked by the other writing thread and no other writing
976 * threads want to lock @lock. This lock has to be unlocked by
977 * g_static_rw_lock_reader_unlock().
979 * #GStaticRWLock is not recursive. It might seem to be possible to
980 * recursively lock for reading, but that can result in a deadlock, due
981 * to writer preference.
983 * Deprecated: 2.32: Use g_rw_lock_reader_lock() instead
986 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
988 g_return_if_fail (lock);
990 if (!g_threads_got_initialized)
993 g_static_mutex_lock (&lock->mutex);
994 lock->want_to_read++;
995 while (lock->have_writer || lock->want_to_write)
996 g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
997 lock->want_to_read--;
998 lock->read_counter++;
999 g_static_mutex_unlock (&lock->mutex);
1003 * g_static_rw_lock_reader_trylock:
1004 * @lock: a #GStaticRWLock to lock for reading.
1005 * @Returns: %TRUE, if @lock could be locked for reading.
1007 * Tries to lock @lock for reading. If @lock is already locked for
1008 * writing by another thread or if another thread is already waiting to
1009 * lock @lock for writing, immediately returns %FALSE. Otherwise locks
1010 * @lock for reading and returns %TRUE. This lock has to be unlocked by
1011 * g_static_rw_lock_reader_unlock().
1013 * Deprectated: 2.32: Use g_rw_lock_reader_trylock() instead
1016 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
1018 gboolean ret_val = FALSE;
1020 g_return_val_if_fail (lock, FALSE);
1022 if (!g_threads_got_initialized)
1025 g_static_mutex_lock (&lock->mutex);
1026 if (!lock->have_writer && !lock->want_to_write)
1028 lock->read_counter++;
1031 g_static_mutex_unlock (&lock->mutex);
1036 * g_static_rw_lock_reader_unlock:
1037 * @lock: a #GStaticRWLock to unlock after reading.
1039 * Unlocks @lock. If a thread waits to lock @lock for writing and all
1040 * locks for reading have been unlocked, the waiting thread is woken up
1041 * and can lock @lock for writing.
1043 * Deprectated: 2.32: Use g_rw_lock_reader_unlock() instead
1046 g_static_rw_lock_reader_unlock (GStaticRWLock* lock)
1048 g_return_if_fail (lock);
1050 if (!g_threads_got_initialized)
1053 g_static_mutex_lock (&lock->mutex);
1054 lock->read_counter--;
1055 if (lock->read_counter == 0)
1056 g_static_rw_lock_signal (lock);
1057 g_static_mutex_unlock (&lock->mutex);
1061 * g_static_rw_lock_writer_lock:
1062 * @lock: a #GStaticRWLock to lock for writing.
1064 * Locks @lock for writing. If @lock is already locked for writing or
1065 * reading by other threads, this function will block until @lock is
1066 * completely unlocked and then lock @lock for writing. While this
1067 * functions waits to lock @lock, no other thread can lock @lock for
1068 * reading. When @lock is locked for writing, no other thread can lock
1069 * @lock (neither for reading nor writing). This lock has to be
1070 * unlocked by g_static_rw_lock_writer_unlock().
1072 * Deprectated: 2.32: Use g_rw_lock_writer_lock() instead
1075 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
1077 g_return_if_fail (lock);
1079 if (!g_threads_got_initialized)
1082 g_static_mutex_lock (&lock->mutex);
1083 lock->want_to_write++;
1084 while (lock->have_writer || lock->read_counter)
1085 g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
1086 lock->want_to_write--;
1087 lock->have_writer = TRUE;
1088 g_static_mutex_unlock (&lock->mutex);
1092 * g_static_rw_lock_writer_trylock:
1093 * @lock: a #GStaticRWLock to lock for writing.
1094 * @Returns: %TRUE, if @lock could be locked for writing.
1096 * Tries to lock @lock for writing. If @lock is already locked (for
1097 * either reading or writing) by another thread, it immediately returns
1098 * %FALSE. Otherwise it locks @lock for writing and returns %TRUE. This
1099 * lock has to be unlocked by g_static_rw_lock_writer_unlock().
1101 * Deprectated: 2.32: Use g_rw_lock_writer_trylock() instead
1104 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
1106 gboolean ret_val = FALSE;
1108 g_return_val_if_fail (lock, FALSE);
1110 if (!g_threads_got_initialized)
1113 g_static_mutex_lock (&lock->mutex);
1114 if (!lock->have_writer && !lock->read_counter)
1116 lock->have_writer = TRUE;
1119 g_static_mutex_unlock (&lock->mutex);
1124 * g_static_rw_lock_writer_unlock:
1125 * @lock: a #GStaticRWLock to unlock after writing.
1127 * Unlocks @lock. If a thread is waiting to lock @lock for writing and
1128 * all locks for reading have been unlocked, the waiting thread is
1129 * woken up and can lock @lock for writing. If no thread is waiting to
1130 * lock @lock for writing, and some thread or threads are waiting to
1131 * lock @lock for reading, the waiting threads are woken up and can
1132 * lock @lock for reading.
1134 * Deprectated: 2.32: Use g_rw_lock_writer_unlock() instead
1137 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
1139 g_return_if_fail (lock);
1141 if (!g_threads_got_initialized)
1144 g_static_mutex_lock (&lock->mutex);
1145 lock->have_writer = FALSE;
1146 g_static_rw_lock_signal (lock);
1147 g_static_mutex_unlock (&lock->mutex);
1151 * g_static_rw_lock_free:
1152 * @lock: a #GStaticRWLock to be freed.
1154 * Releases all resources allocated to @lock.
1156 * You don't have to call this functions for a #GStaticRWLock with an
1157 * unbounded lifetime, i.e. objects declared 'static', but if you have
1158 * a #GStaticRWLock as a member of a structure, and the structure is
1159 * freed, you should also free the #GStaticRWLock.
1161 * Deprecated: 2.32: Use a #GRWLock instead
1164 g_static_rw_lock_free (GStaticRWLock* lock)
1166 g_return_if_fail (lock);
1168 if (lock->read_cond)
1170 g_cond_free (lock->read_cond);
1171 lock->read_cond = NULL;
1173 if (lock->write_cond)
1175 g_cond_free (lock->write_cond);
1176 lock->write_cond = NULL;
1178 g_static_mutex_free (&lock->mutex);
1181 /* GPrivate {{{1 ------------------------------------------------------ */
1185 * @notify: a #GDestroyNotify
1187 * Deprecated:2.32: dynamic allocation of #GPrivate is a bad idea. Use
1188 * static storage and G_PRIVATE_INIT() instead.
1190 * Returns: a newly allocated #GPrivate (which can never be destroyed)
1193 g_private_new (GDestroyNotify notify)
1195 GPrivate tmp = G_PRIVATE_INIT (notify);
1198 key = g_slice_new (GPrivate);
1204 /* {{{1 GStaticPrivate */
1206 typedef struct _GStaticPrivateNode GStaticPrivateNode;
1207 struct _GStaticPrivateNode
1210 GDestroyNotify destroy;
1211 GStaticPrivate *owner;
1215 g_static_private_cleanup (gpointer data)
1217 GArray *array = data;
1220 for (i = 0; i < array->len; i++ )
1222 GStaticPrivateNode *node = &g_array_index (array, GStaticPrivateNode, i);
1224 node->destroy (node->data);
1227 g_array_free (array, TRUE);
1230 GPrivate static_private_private = G_PRIVATE_INIT (g_static_private_cleanup);
1235 * A #GStaticPrivate works almost like a #GPrivate, but it has one
1236 * significant advantage. It doesn't need to be created at run-time
1237 * like a #GPrivate, but can be defined at compile-time. This is
1238 * similar to the difference between #GMutex and #GStaticMutex. Now
1239 * look at our <function>give_me_next_number()</function> example with
1243 * <title>Using GStaticPrivate for per-thread data</title>
1246 * give_me_next_number (<!-- -->)
1248 * static GStaticPrivate current_number_key = G_STATIC_PRIVATE_INIT;
1249 * int *current_number = g_static_private_get (&current_number_key);
1251 * if (!current_number)
1253 * current_number = g_new (int,1);
1254 * *current_number = 0;
1255 * g_static_private_set (&current_number_key, current_number, g_free);
1258 * *current_number = calc_next_number (*current_number);
1260 * return *current_number;
1267 * G_STATIC_PRIVATE_INIT:
1269 * Every #GStaticPrivate must be initialized with this macro, before it
1273 * GStaticPrivate my_private = G_STATIC_PRIVATE_INIT;
1278 * g_static_private_init:
1279 * @private_key: a #GStaticPrivate to be initialized
1281 * Initializes @private_key. Alternatively you can initialize it with
1282 * #G_STATIC_PRIVATE_INIT.
1285 g_static_private_init (GStaticPrivate *private_key)
1287 private_key->index = 0;
1291 * g_static_private_get:
1292 * @private_key: a #GStaticPrivate
1294 * Works like g_private_get() only for a #GStaticPrivate.
1296 * This function works even if g_thread_init() has not yet been called.
1298 * Returns: the corresponding pointer
1301 g_static_private_get (GStaticPrivate *private_key)
1304 gpointer ret = NULL;
1306 array = g_private_get (&static_private_private);
1308 if (array && private_key->index != 0 && private_key->index <= array->len)
1310 GStaticPrivateNode *node;
1312 node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
1314 /* Deal with the possibility that the GStaticPrivate which used
1315 * to have this index got freed and the index got allocated to
1316 * a new one. In this case, the data in the node is stale, so
1317 * free it and return NULL.
1319 if (G_UNLIKELY (node->owner != private_key))
1322 node->destroy (node->data);
1323 node->destroy = NULL;
1334 * g_static_private_set:
1335 * @private_key: a #GStaticPrivate
1336 * @data: the new pointer
1337 * @notify: a function to be called with the pointer whenever the
1338 * current thread ends or sets this pointer again
1340 * Sets the pointer keyed to @private_key for the current thread and
1341 * the function @notify to be called with that pointer (%NULL or
1342 * non-%NULL), whenever the pointer is set again or whenever the
1343 * current thread ends.
1345 * This function works even if g_thread_init() has not yet been called.
1346 * If g_thread_init() is called later, the @data keyed to @private_key
1347 * will be inherited only by the main thread, i.e. the one that called
1350 * <note><para>@notify is used quite differently from @destructor in
1351 * g_private_new().</para></note>
1354 g_static_private_set (GStaticPrivate *private_key,
1356 GDestroyNotify notify)
1359 static guint next_index = 0;
1360 GStaticPrivateNode *node;
1362 if (!private_key->index)
1366 if (!private_key->index)
1368 if (g_thread_free_indices)
1370 private_key->index = GPOINTER_TO_UINT (g_thread_free_indices->data);
1371 g_thread_free_indices = g_slist_delete_link (g_thread_free_indices,
1372 g_thread_free_indices);
1375 private_key->index = ++next_index;
1378 G_UNLOCK (g_thread);
1381 array = g_private_get (&static_private_private);
1384 array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
1385 g_private_set (&static_private_private, array);
1387 if (private_key->index > array->len)
1388 g_array_set_size (array, private_key->index);
1390 node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
1393 node->destroy (node->data);
1396 node->destroy = notify;
1397 node->owner = private_key;
1401 * g_static_private_free:
1402 * @private_key: a #GStaticPrivate to be freed
1404 * Releases all resources allocated to @private_key.
1406 * You don't have to call this functions for a #GStaticPrivate with an
1407 * unbounded lifetime, i.e. objects declared 'static', but if you have
1408 * a #GStaticPrivate as a member of a structure and the structure is
1409 * freed, you should also free the #GStaticPrivate.
1412 g_static_private_free (GStaticPrivate *private_key)
1414 guint idx = private_key->index;
1419 private_key->index = 0;
1421 /* Freeing the per-thread data is deferred to either the
1422 * thread end or the next g_static_private_get() call for
1426 g_thread_free_indices = g_slist_prepend (g_thread_free_indices,
1427 GUINT_TO_POINTER (idx));
1428 G_UNLOCK (g_thread);
1431 /* GMutex {{{1 ------------------------------------------------------ */
1436 * Allocates and initializes a new #GMutex.
1438 * Returns: a newly allocated #GMutex. Use g_mutex_free() to free
1440 * Deprecated:3.32:GMutex can now be statically allocated, or embedded
1441 * in structures and initialised with g_mutex_init().
1448 mutex = g_slice_new (GMutex);
1449 g_mutex_init (mutex);
1458 * Destroys a @mutex that has been created with g_mutex_new().
1460 * Calling g_mutex_free() on a locked mutex may result
1461 * in undefined behaviour.
1463 * Deprecated:3.32:GMutex can now be statically allocated, or embedded
1464 * in structures and initialised with g_mutex_init().
1467 g_mutex_free (GMutex *mutex)
1469 g_mutex_clear (mutex);
1470 g_slice_free (GMutex, mutex);
1473 /* GCond {{{1 ------------------------------------------------------ */
1478 * Allocates and initializes a new #GCond.
1480 * Returns: a newly allocated #GCond. Free with g_cond_free()
1482 * Deprecated:3.32:GCond can now be statically allocated, or embedded
1483 * in structures and initialised with g_cond_init().
1490 cond = g_slice_new (GCond);
1500 * Destroys a #GCond that has been created with g_cond_new().
1502 * Calling g_cond_free() for a #GCond on which threads are
1503 * blocking leads to undefined behaviour.
1505 * Deprecated:3.32:GCond can now be statically allocated, or embedded
1506 * in structures and initialised with g_cond_init().
1509 g_cond_free (GCond *cond)
1511 g_cond_clear (cond);
1512 g_slice_free (GCond, cond);
1516 /* vim: set foldmethod=marker: */