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;
151 GSystemThread zero_thread; /* This is initialized to all zero */
156 * @vtable: a function table of type #GThreadFunctions, that provides
157 * the entry points to the thread system to be used. Since 2.32,
158 * this parameter is ignored and should always be %NULL
160 * If you use GLib from more than one thread, you must initialize the
161 * thread system by calling g_thread_init().
163 * Since version 2.24, calling g_thread_init() multiple times is allowed,
164 * but nothing happens except for the first call.
166 * Since version 2.32, GLib does not support custom thread implementations
167 * anymore and the @vtable parameter is ignored and you should pass %NULL.
169 * <note><para>g_thread_init() must not be called directly or indirectly
170 * in a callback from GLib. Also no mutexes may be currently locked while
171 * calling g_thread_init().</para></note>
173 * <note><para>To use g_thread_init() in your program, you have to link
174 * with the libraries that the command <command>pkg-config --libs
175 * gthread-2.0</command> outputs. This is not the case for all the
176 * other thread-related functions of GLib. Those can be used without
177 * having to link with the thread libraries.</para></note>
181 * g_thread_get_initialized:
183 * Indicates if g_thread_init() has been called.
185 * Returns: %TRUE if threads have been initialized.
190 g_thread_get_initialized (void)
192 return g_thread_supported ();
195 /* We need this for ABI compatibility */
196 void g_thread_init_glib (void) { }
198 /* Internal variables {{{1 */
200 static GRealThread *g_thread_all_threads = NULL;
201 static GSList *g_thread_free_indices = NULL;
203 /* Protects g_thread_all_threads and g_thread_free_indices */
204 G_LOCK_DEFINE_STATIC (g_thread);
206 /* Misc. GThread functions {{{1 */
209 * g_thread_set_priority:
210 * @thread: a #GThread.
213 * This function does nothing.
215 * Deprecated:2.32: Thread priorities no longer have any effect.
218 g_thread_set_priority (GThread *thread,
219 GThreadPriority priority)
225 * @thread_func: function to call for all #GThread structures
226 * @user_data: second argument to @thread_func
228 * Call @thread_func on all #GThreads that have been
229 * created with g_thread_create().
231 * Note that threads may decide to exit while @thread_func is
232 * running, so without intimate knowledge about the lifetime of
233 * foreign threads, @thread_func shouldn't access the GThread*
234 * pointer passed in as first argument. However, @thread_func will
235 * not be called for threads which are known to have exited already.
237 * Due to thread lifetime checks, this function has an execution complexity
238 * which is quadratic in the number of existing threads.
242 * Deprecated:2.32: There aren't many things you can do with a #GThread,
243 * except comparing it with one that was returned from g_thread_create().
244 * There are better ways to find out if your thread is still alive.
247 g_thread_foreach (GFunc thread_func,
250 GSList *slist = NULL;
252 g_return_if_fail (thread_func != NULL);
253 /* snapshot the list of threads for iteration */
255 for (thread = g_thread_all_threads; thread; thread = thread->next)
256 slist = g_slist_prepend (slist, thread);
258 /* walk the list, skipping non-existent threads */
261 GSList *node = slist;
263 /* check whether the current thread still exists */
265 for (thread = g_thread_all_threads; thread; thread = thread->next)
266 if (thread == node->data)
270 thread_func (thread, user_data);
271 g_slist_free_1 (node);
276 g_enumerable_thread_remove (gpointer data)
278 GRealThread *thread = data;
282 for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
289 g_thread_all_threads = t->next;
296 GPrivate enumerable_thread_private = G_PRIVATE_INIT (g_enumerable_thread_remove);
299 g_enumerable_thread_add (GRealThread *thread)
302 thread->next = g_thread_all_threads;
303 g_thread_all_threads = thread;
306 g_private_set (&enumerable_thread_private, thread);
310 * @func: a function to execute in the new thread
311 * @data: an argument to supply to the new thread
312 * @joinable: should this thread be joinable?
313 * @error: return location for error, or %NULL
315 * This function creates a new thread.
317 * If @joinable is %TRUE, you can wait for this threads termination
318 * calling g_thread_join(). Otherwise the thread will just disappear
319 * when it terminates.
321 * The new thread executes the function @func with the argument @data.
322 * If the thread was created successfully, it is returned.
324 * @error can be %NULL to ignore errors, or non-%NULL to report errors.
325 * The error is set, if and only if the function returns %NULL.
327 * Returns: the new #GThread on success
329 * Deprecated:2.32: Use g_thread_new() instead
332 g_thread_create (GThreadFunc func,
337 return g_thread_new_internal (NULL, func, data, joinable, 0, g_enumerable_thread_add, error);
341 * g_thread_create_full:
342 * @func: a function to execute in the new thread.
343 * @data: an argument to supply to the new thread.
344 * @stack_size: a stack size for the new thread.
345 * @joinable: should this thread be joinable?
348 * @error: return location for error.
349 * @Returns: the new #GThread on success.
351 * This function creates a new thread.
353 * Deprecated:2.32: The @bound and @priority arguments are now ignored.
354 * Use g_thread_new() or g_thread_new_full() instead.
357 g_thread_create_full (GThreadFunc func,
362 GThreadPriority priority,
365 return g_thread_new_internal (NULL, func, data, joinable, stack_size, g_enumerable_thread_add, error);
370 /* GOnce {{{1 ------------------------------------------------------------- */
372 g_once_init_enter_impl (volatile gsize *location)
374 return (g_once_init_enter) (location);
377 /* GStaticMutex {{{1 ------------------------------------------------------ */
382 * A #GStaticMutex works like a #GMutex.
384 * Prior to GLib 2.32, GStaticMutex had the significant advantage
385 * that it doesn't need to be created at run-time, but can be defined
386 * at compile-time. Since 2.32, #GMutex can be statically allocated
387 * as well, and GStaticMutex has been deprecated.
389 * Here is a version of our give_me_next_number() example using
394 * Using <structname>GStaticMutex</structname>
395 * to simplify thread-safe programming
399 * give_me_next_number (void)
401 * static int current_number = 0;
403 * static GStaticMutex mutex = G_STATIC_MUTEX_INIT;
405 * g_static_mutex_lock (&mutex);
406 * ret_val = current_number = calc_next_number (current_number);
407 * g_static_mutex_unlock (&mutex);
414 * Sometimes you would like to dynamically create a mutex. If you don't
415 * want to require prior calling to g_thread_init(), because your code
416 * should also be usable in non-threaded programs, you are not able to
417 * use g_mutex_new() and thus #GMutex, as that requires a prior call to
418 * g_thread_init(). In theses cases you can also use a #GStaticMutex.
419 * It must be initialized with g_static_mutex_init() before using it
420 * and freed with with g_static_mutex_free() when not needed anymore to
421 * free up any allocated resources.
423 * Even though #GStaticMutex is not opaque, it should only be used with
424 * the following functions, as it is defined differently on different
427 * All of the <function>g_static_mutex_*</function> functions apart
428 * from <function>g_static_mutex_get_mutex</function> can also be used
429 * even if g_thread_init() has not yet been called. Then they do
430 * nothing, apart from <function>g_static_mutex_trylock</function>,
431 * which does nothing but returning %TRUE.
433 * <note><para>All of the <function>g_static_mutex_*</function>
434 * functions are actually macros. Apart from taking their addresses, you
435 * can however use them as if they were functions.</para></note>
439 * G_STATIC_MUTEX_INIT:
441 * A #GStaticMutex must be initialized with this macro, before it can
442 * be used. This macro can used be to initialize a variable, but it
443 * cannot be assigned to a variable. In that case you have to use
444 * g_static_mutex_init().
447 * GStaticMutex my_mutex = G_STATIC_MUTEX_INIT;
452 * g_static_mutex_init:
453 * @mutex: a #GStaticMutex to be initialized.
455 * Initializes @mutex.
456 * Alternatively you can initialize it with #G_STATIC_MUTEX_INIT.
458 * Deprecated: 2.32: Use g_mutex_init()
461 g_static_mutex_init (GStaticMutex *mutex)
463 static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
465 g_return_if_fail (mutex);
470 /* IMPLEMENTATION NOTE:
472 * On some platforms a GStaticMutex is actually a normal GMutex stored
473 * inside of a structure instead of being allocated dynamically. We can
474 * only do this for platforms on which we know, in advance, how to
475 * allocate (size) and initialise (value) that memory.
477 * On other platforms, a GStaticMutex is nothing more than a pointer to
478 * a GMutex. In that case, the first access we make to the static mutex
479 * must first allocate the normal GMutex and store it into the pointer.
481 * configure.ac writes macros into glibconfig.h to determine if
482 * g_static_mutex_get_mutex() accesses the structure in memory directly
483 * (on platforms where we are able to do that) or if it ends up here,
484 * where we may have to allocate the GMutex before returning it.
488 * g_static_mutex_get_mutex:
489 * @mutex: a #GStaticMutex.
490 * @Returns: the #GMutex corresponding to @mutex.
492 * For some operations (like g_cond_wait()) you must have a #GMutex
493 * instead of a #GStaticMutex. This function will return the
494 * corresponding #GMutex for @mutex.
496 * Deprecated: 2.32: Just use a #GMutex
499 g_static_mutex_get_mutex_impl (GStaticMutex* mutex)
503 if (!g_thread_supported ())
506 result = g_atomic_pointer_get (&mutex->mutex);
510 g_mutex_lock (&g_once_mutex);
512 result = mutex->mutex;
515 result = g_mutex_new ();
516 g_atomic_pointer_set (&mutex->mutex, result);
519 g_mutex_unlock (&g_once_mutex);
525 /* IMPLEMENTATION NOTE:
527 * g_static_mutex_lock(), g_static_mutex_trylock() and
528 * g_static_mutex_unlock() are all preprocessor macros that wrap the
529 * corresponding g_mutex_*() function around a call to
530 * g_static_mutex_get_mutex().
534 * g_static_mutex_lock:
535 * @mutex: a #GStaticMutex.
537 * Works like g_mutex_lock(), but for a #GStaticMutex.
539 * Deprecated: 2.32: Use g_mutex_lock()
543 * g_static_mutex_trylock:
544 * @mutex: a #GStaticMutex.
545 * @Returns: %TRUE, if the #GStaticMutex could be locked.
547 * Works like g_mutex_trylock(), but for a #GStaticMutex.
549 * Deprecated: 2.32: Use g_mutex_trylock()
553 * g_static_mutex_unlock:
554 * @mutex: a #GStaticMutex.
556 * Works like g_mutex_unlock(), but for a #GStaticMutex.
558 * Deprecated: 2.32: Use g_mutex_unlock()
562 * g_static_mutex_free:
563 * @mutex: a #GStaticMutex to be freed.
565 * Releases all resources allocated to @mutex.
567 * You don't have to call this functions for a #GStaticMutex with an
568 * unbounded lifetime, i.e. objects declared 'static', but if you have
569 * a #GStaticMutex as a member of a structure and the structure is
570 * freed, you should also free the #GStaticMutex.
572 * <note><para>Calling g_static_mutex_free() on a locked mutex may
573 * result in undefined behaviour.</para></note>
575 * Deprecated: 2.32: Use g_mutex_free()
578 g_static_mutex_free (GStaticMutex* mutex)
580 GMutex **runtime_mutex;
582 g_return_if_fail (mutex);
584 /* The runtime_mutex is the first (or only) member of GStaticMutex,
585 * see both versions (of glibconfig.h) in configure.ac. Note, that
586 * this variable is NULL, if g_thread_init() hasn't been called or
587 * if we're using the default thread implementation and it provides
589 runtime_mutex = ((GMutex**)mutex);
592 g_mutex_free (*runtime_mutex);
594 *runtime_mutex = NULL;
597 /* {{{1 GStaticRecMutex */
602 * A #GStaticRecMutex works like a #GStaticMutex, but it can be locked
603 * multiple times by one thread. If you enter it n times, you have to
604 * unlock it n times again to let other threads lock it. An exception
605 * is the function g_static_rec_mutex_unlock_full(): that allows you to
606 * unlock a #GStaticRecMutex completely returning the depth, (i.e. the
607 * number of times this mutex was locked). The depth can later be used
608 * to restore the state of the #GStaticRecMutex by calling
609 * g_static_rec_mutex_lock_full(). In GLib 2.32, #GStaticRecMutex has
610 * been deprecated in favor of #GRecMutex.
612 * Even though #GStaticRecMutex is not opaque, it should only be used
613 * with the following functions.
615 * All of the <function>g_static_rec_mutex_*</function> functions can
616 * be used even if g_thread_init() has not been called. Then they do
617 * nothing, apart from <function>g_static_rec_mutex_trylock</function>,
618 * which does nothing but returning %TRUE.
622 * G_STATIC_REC_MUTEX_INIT:
624 * A #GStaticRecMutex must be initialized with this macro before it can
625 * be used. This macro can used be to initialize a variable, but it
626 * cannot be assigned to a variable. In that case you have to use
627 * g_static_rec_mutex_init().
630 * GStaticRecMutex my_mutex = G_STATIC_REC_MUTEX_INIT;
635 * g_static_rec_mutex_init:
636 * @mutex: a #GStaticRecMutex to be initialized.
638 * A #GStaticRecMutex must be initialized with this function before it
639 * can be used. Alternatively you can initialize it with
640 * #G_STATIC_REC_MUTEX_INIT.
642 * Deprecated: 2.32: Use g_rec_mutex_init()
645 g_static_rec_mutex_init (GStaticRecMutex *mutex)
647 static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
649 g_return_if_fail (mutex);
655 * g_static_rec_mutex_lock:
656 * @mutex: a #GStaticRecMutex to lock.
658 * Locks @mutex. If @mutex is already locked by another thread, the
659 * current thread will block until @mutex is unlocked by the other
660 * thread. If @mutex is already locked by the calling thread, this
661 * functions increases the depth of @mutex and returns immediately.
663 * Deprecated: 2.32: Use g_rec_mutex_lock()
666 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
670 g_return_if_fail (mutex);
672 if (!g_thread_supported ())
675 g_system_thread_self (&self);
677 if (g_system_thread_equal (&self, &mutex->owner))
682 g_static_mutex_lock (&mutex->mutex);
683 g_system_thread_assign (mutex->owner, self);
688 * g_static_rec_mutex_trylock:
689 * @mutex: a #GStaticRecMutex to lock.
690 * @Returns: %TRUE, if @mutex could be locked.
692 * Tries to lock @mutex. If @mutex is already locked by another thread,
693 * it immediately returns %FALSE. Otherwise it locks @mutex and returns
694 * %TRUE. If @mutex is already locked by the calling thread, this
695 * functions increases the depth of @mutex and immediately returns
698 * Deprecated: 2.32: Use g_rec_mutex_trylock()
701 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
705 g_return_val_if_fail (mutex, FALSE);
707 if (!g_thread_supported ())
710 g_system_thread_self (&self);
712 if (g_system_thread_equal (&self, &mutex->owner))
718 if (!g_static_mutex_trylock (&mutex->mutex))
721 g_system_thread_assign (mutex->owner, self);
727 * g_static_rec_mutex_unlock:
728 * @mutex: a #GStaticRecMutex to unlock.
730 * Unlocks @mutex. Another thread will be allowed to lock @mutex only
731 * when it has been unlocked as many times as it had been locked
732 * before. If @mutex is completely unlocked and another thread is
733 * blocked in a g_static_rec_mutex_lock() call for @mutex, it will be
734 * woken and can lock @mutex itself.
736 * Deprecated: 2.32: Use g_rec_mutex_unlock()
739 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
741 g_return_if_fail (mutex);
743 if (!g_thread_supported ())
746 if (mutex->depth > 1)
751 g_system_thread_assign (mutex->owner, zero_thread);
752 g_static_mutex_unlock (&mutex->mutex);
756 * g_static_rec_mutex_lock_full:
757 * @mutex: a #GStaticRecMutex to lock.
758 * @depth: number of times this mutex has to be unlocked to be
759 * completely unlocked.
761 * Works like calling g_static_rec_mutex_lock() for @mutex @depth times.
763 * Deprecated: 2.32: Use g_rec_mutex_lock()
766 g_static_rec_mutex_lock_full (GStaticRecMutex *mutex,
770 g_return_if_fail (mutex);
772 if (!g_thread_supported ())
778 g_system_thread_self (&self);
780 if (g_system_thread_equal (&self, &mutex->owner))
782 mutex->depth += depth;
785 g_static_mutex_lock (&mutex->mutex);
786 g_system_thread_assign (mutex->owner, self);
787 mutex->depth = depth;
791 * g_static_rec_mutex_unlock_full:
792 * @mutex: a #GStaticRecMutex to completely unlock.
793 * @Returns: number of times @mutex has been locked by the current
796 * Completely unlocks @mutex. If another thread is blocked in a
797 * g_static_rec_mutex_lock() call for @mutex, it will be woken and can
798 * lock @mutex itself. This function returns the number of times that
799 * @mutex has been locked by the current thread. To restore the state
800 * before the call to g_static_rec_mutex_unlock_full() you can call
801 * g_static_rec_mutex_lock_full() with the depth returned by this
804 * Deprecated: 2.32: Use g_rec_mutex_unlock()
807 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
811 g_return_val_if_fail (mutex, 0);
813 if (!g_thread_supported ())
816 depth = mutex->depth;
818 g_system_thread_assign (mutex->owner, zero_thread);
820 g_static_mutex_unlock (&mutex->mutex);
826 * g_static_rec_mutex_free:
827 * @mutex: a #GStaticRecMutex to be freed.
829 * Releases all resources allocated to a #GStaticRecMutex.
831 * You don't have to call this functions for a #GStaticRecMutex with an
832 * unbounded lifetime, i.e. objects declared 'static', but if you have
833 * a #GStaticRecMutex as a member of a structure and the structure is
834 * freed, you should also free the #GStaticRecMutex.
836 * Deprecated: 2.32: Use g_rec_mutex_clear()
839 g_static_rec_mutex_free (GStaticRecMutex *mutex)
841 g_return_if_fail (mutex);
843 g_static_mutex_free (&mutex->mutex);
846 /* GStaticRWLock {{{1 ----------------------------------------------------- */
851 * The #GStaticRWLock struct represents a read-write lock. A read-write
852 * lock can be used for protecting data that some portions of code only
853 * read from, while others also write. In such situations it is
854 * desirable that several readers can read at once, whereas of course
855 * only one writer may write at a time. Take a look at the following
859 * <title>An array with access functions</title>
861 * GStaticRWLock rwlock = G_STATIC_RW_LOCK_INIT;
865 * my_array_get (guint index)
867 * gpointer retval = NULL;
872 * g_static_rw_lock_reader_lock (&rwlock);
873 * if (index < array->len)
874 * retval = g_ptr_array_index (array, index);
875 * g_static_rw_lock_reader_unlock (&rwlock);
881 * my_array_set (guint index, gpointer data)
883 * g_static_rw_lock_writer_lock (&rwlock);
886 * array = g_ptr_array_new (<!-- -->);
888 * if (index >= array->len)
889 * g_ptr_array_set_size (array, index+1);
890 * g_ptr_array_index (array, index) = data;
892 * g_static_rw_lock_writer_unlock (&rwlock);
897 * This example shows an array which can be accessed by many readers
898 * (the <function>my_array_get()</function> function) simultaneously,
899 * whereas the writers (the <function>my_array_set()</function>
900 * function) will only be allowed once at a time and only if no readers
901 * currently access the array. This is because of the potentially
902 * dangerous resizing of the array. Using these functions is fully
903 * multi-thread safe now.
905 * Most of the time, writers should have precedence over readers. That
906 * means, for this implementation, that as soon as a writer wants to
907 * lock the data, no other reader is allowed to lock the data, whereas,
908 * of course, the readers that already have locked the data are allowed
909 * to finish their operation. As soon as the last reader unlocks the
910 * data, the writer will lock it.
912 * Even though #GStaticRWLock is not opaque, it should only be used
913 * with the following functions.
915 * All of the <function>g_static_rw_lock_*</function> functions can be
916 * used even if g_thread_init() has not been called. Then they do
917 * nothing, apart from <function>g_static_rw_lock_*_trylock</function>,
918 * which does nothing but returning %TRUE.
920 * <note><para>A read-write lock has a higher overhead than a mutex. For
921 * example, both g_static_rw_lock_reader_lock() and
922 * g_static_rw_lock_reader_unlock() have to lock and unlock a
923 * #GStaticMutex, so it takes at least twice the time to lock and unlock
924 * a #GStaticRWLock that it does to lock and unlock a #GStaticMutex. So
925 * only data structures that are accessed by multiple readers, and which
926 * keep the lock for a considerable time justify a #GStaticRWLock. The
927 * above example most probably would fare better with a
928 * #GStaticMutex.</para></note>
930 * Deprecated: 2.32: Use a #GRWLock instead
934 * G_STATIC_RW_LOCK_INIT:
936 * A #GStaticRWLock must be initialized with this macro before it can
937 * be used. This macro can used be to initialize a variable, but it
938 * cannot be assigned to a variable. In that case you have to use
939 * g_static_rw_lock_init().
942 * GStaticRWLock my_lock = G_STATIC_RW_LOCK_INIT;
947 * g_static_rw_lock_init:
948 * @lock: a #GStaticRWLock to be initialized.
950 * A #GStaticRWLock must be initialized with this function before it
951 * can be used. Alternatively you can initialize it with
952 * #G_STATIC_RW_LOCK_INIT.
954 * Deprecated: 2.32: Use g_rw_lock_init() instead
957 g_static_rw_lock_init (GStaticRWLock* lock)
959 static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
961 g_return_if_fail (lock);
967 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
970 *cond = g_cond_new ();
971 g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
975 g_static_rw_lock_signal (GStaticRWLock* lock)
977 if (lock->want_to_write && lock->write_cond)
978 g_cond_signal (lock->write_cond);
979 else if (lock->want_to_read && lock->read_cond)
980 g_cond_broadcast (lock->read_cond);
984 * g_static_rw_lock_reader_lock:
985 * @lock: a #GStaticRWLock to lock for reading.
987 * Locks @lock for reading. There may be unlimited concurrent locks for
988 * reading of a #GStaticRWLock at the same time. If @lock is already
989 * locked for writing by another thread or if another thread is already
990 * waiting to lock @lock for writing, this function will block until
991 * @lock is unlocked by the other writing thread and no other writing
992 * threads want to lock @lock. This lock has to be unlocked by
993 * g_static_rw_lock_reader_unlock().
995 * #GStaticRWLock is not recursive. It might seem to be possible to
996 * recursively lock for reading, but that can result in a deadlock, due
997 * to writer preference.
999 * Deprecated: 2.32: Use g_rw_lock_reader_lock() instead
1002 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
1004 g_return_if_fail (lock);
1006 if (!g_threads_got_initialized)
1009 g_static_mutex_lock (&lock->mutex);
1010 lock->want_to_read++;
1011 while (lock->have_writer || lock->want_to_write)
1012 g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
1013 lock->want_to_read--;
1014 lock->read_counter++;
1015 g_static_mutex_unlock (&lock->mutex);
1019 * g_static_rw_lock_reader_trylock:
1020 * @lock: a #GStaticRWLock to lock for reading.
1021 * @Returns: %TRUE, if @lock could be locked for reading.
1023 * Tries to lock @lock for reading. If @lock is already locked for
1024 * writing by another thread or if another thread is already waiting to
1025 * lock @lock for writing, immediately returns %FALSE. Otherwise locks
1026 * @lock for reading and returns %TRUE. This lock has to be unlocked by
1027 * g_static_rw_lock_reader_unlock().
1029 * Deprectated: 2.32: Use g_rw_lock_reader_trylock() instead
1032 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
1034 gboolean ret_val = FALSE;
1036 g_return_val_if_fail (lock, FALSE);
1038 if (!g_threads_got_initialized)
1041 g_static_mutex_lock (&lock->mutex);
1042 if (!lock->have_writer && !lock->want_to_write)
1044 lock->read_counter++;
1047 g_static_mutex_unlock (&lock->mutex);
1052 * g_static_rw_lock_reader_unlock:
1053 * @lock: a #GStaticRWLock to unlock after reading.
1055 * Unlocks @lock. If a thread waits to lock @lock for writing and all
1056 * locks for reading have been unlocked, the waiting thread is woken up
1057 * and can lock @lock for writing.
1059 * Deprectated: 2.32: Use g_rw_lock_reader_unlock() instead
1062 g_static_rw_lock_reader_unlock (GStaticRWLock* lock)
1064 g_return_if_fail (lock);
1066 if (!g_threads_got_initialized)
1069 g_static_mutex_lock (&lock->mutex);
1070 lock->read_counter--;
1071 if (lock->read_counter == 0)
1072 g_static_rw_lock_signal (lock);
1073 g_static_mutex_unlock (&lock->mutex);
1077 * g_static_rw_lock_writer_lock:
1078 * @lock: a #GStaticRWLock to lock for writing.
1080 * Locks @lock for writing. If @lock is already locked for writing or
1081 * reading by other threads, this function will block until @lock is
1082 * completely unlocked and then lock @lock for writing. While this
1083 * functions waits to lock @lock, no other thread can lock @lock for
1084 * reading. When @lock is locked for writing, no other thread can lock
1085 * @lock (neither for reading nor writing). This lock has to be
1086 * unlocked by g_static_rw_lock_writer_unlock().
1088 * Deprectated: 2.32: Use g_rw_lock_writer_lock() instead
1091 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
1093 g_return_if_fail (lock);
1095 if (!g_threads_got_initialized)
1098 g_static_mutex_lock (&lock->mutex);
1099 lock->want_to_write++;
1100 while (lock->have_writer || lock->read_counter)
1101 g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
1102 lock->want_to_write--;
1103 lock->have_writer = TRUE;
1104 g_static_mutex_unlock (&lock->mutex);
1108 * g_static_rw_lock_writer_trylock:
1109 * @lock: a #GStaticRWLock to lock for writing.
1110 * @Returns: %TRUE, if @lock could be locked for writing.
1112 * Tries to lock @lock for writing. If @lock is already locked (for
1113 * either reading or writing) by another thread, it immediately returns
1114 * %FALSE. Otherwise it locks @lock for writing and returns %TRUE. This
1115 * lock has to be unlocked by g_static_rw_lock_writer_unlock().
1117 * Deprectated: 2.32: Use g_rw_lock_writer_trylock() instead
1120 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
1122 gboolean ret_val = FALSE;
1124 g_return_val_if_fail (lock, FALSE);
1126 if (!g_threads_got_initialized)
1129 g_static_mutex_lock (&lock->mutex);
1130 if (!lock->have_writer && !lock->read_counter)
1132 lock->have_writer = TRUE;
1135 g_static_mutex_unlock (&lock->mutex);
1140 * g_static_rw_lock_writer_unlock:
1141 * @lock: a #GStaticRWLock to unlock after writing.
1143 * Unlocks @lock. If a thread is waiting to lock @lock for writing and
1144 * all locks for reading have been unlocked, the waiting thread is
1145 * woken up and can lock @lock for writing. If no thread is waiting to
1146 * lock @lock for writing, and some thread or threads are waiting to
1147 * lock @lock for reading, the waiting threads are woken up and can
1148 * lock @lock for reading.
1150 * Deprectated: 2.32: Use g_rw_lock_writer_unlock() instead
1153 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
1155 g_return_if_fail (lock);
1157 if (!g_threads_got_initialized)
1160 g_static_mutex_lock (&lock->mutex);
1161 lock->have_writer = FALSE;
1162 g_static_rw_lock_signal (lock);
1163 g_static_mutex_unlock (&lock->mutex);
1167 * g_static_rw_lock_free:
1168 * @lock: a #GStaticRWLock to be freed.
1170 * Releases all resources allocated to @lock.
1172 * You don't have to call this functions for a #GStaticRWLock with an
1173 * unbounded lifetime, i.e. objects declared 'static', but if you have
1174 * a #GStaticRWLock as a member of a structure, and the structure is
1175 * freed, you should also free the #GStaticRWLock.
1177 * Deprecated: 2.32: Use a #GRWLock instead
1180 g_static_rw_lock_free (GStaticRWLock* lock)
1182 g_return_if_fail (lock);
1184 if (lock->read_cond)
1186 g_cond_free (lock->read_cond);
1187 lock->read_cond = NULL;
1189 if (lock->write_cond)
1191 g_cond_free (lock->write_cond);
1192 lock->write_cond = NULL;
1194 g_static_mutex_free (&lock->mutex);
1197 /* GPrivate {{{1 ------------------------------------------------------ */
1201 * @notify: a #GDestroyNotify
1203 * Deprecated:2.32: dynamic allocation of #GPrivate is a bad idea. Use
1204 * static storage and G_PRIVATE_INIT() instead.
1206 * Returns: a newly allocated #GPrivate (which can never be destroyed)
1209 g_private_new (GDestroyNotify notify)
1211 GPrivate tmp = G_PRIVATE_INIT (notify);
1214 key = g_slice_new (GPrivate);
1220 /* {{{1 GStaticPrivate */
1222 typedef struct _GStaticPrivateNode GStaticPrivateNode;
1223 struct _GStaticPrivateNode
1226 GDestroyNotify destroy;
1227 GStaticPrivate *owner;
1231 g_static_private_cleanup (gpointer data)
1233 GArray *array = data;
1236 for (i = 0; i < array->len; i++ )
1238 GStaticPrivateNode *node = &g_array_index (array, GStaticPrivateNode, i);
1240 node->destroy (node->data);
1243 g_array_free (array, TRUE);
1246 GPrivate static_private_private = G_PRIVATE_INIT (g_static_private_cleanup);
1251 * A #GStaticPrivate works almost like a #GPrivate, but it has one
1252 * significant advantage. It doesn't need to be created at run-time
1253 * like a #GPrivate, but can be defined at compile-time. This is
1254 * similar to the difference between #GMutex and #GStaticMutex. Now
1255 * look at our <function>give_me_next_number()</function> example with
1259 * <title>Using GStaticPrivate for per-thread data</title>
1262 * give_me_next_number (<!-- -->)
1264 * static GStaticPrivate current_number_key = G_STATIC_PRIVATE_INIT;
1265 * int *current_number = g_static_private_get (&current_number_key);
1267 * if (!current_number)
1269 * current_number = g_new (int,1);
1270 * *current_number = 0;
1271 * g_static_private_set (&current_number_key, current_number, g_free);
1274 * *current_number = calc_next_number (*current_number);
1276 * return *current_number;
1283 * G_STATIC_PRIVATE_INIT:
1285 * Every #GStaticPrivate must be initialized with this macro, before it
1289 * GStaticPrivate my_private = G_STATIC_PRIVATE_INIT;
1294 * g_static_private_init:
1295 * @private_key: a #GStaticPrivate to be initialized
1297 * Initializes @private_key. Alternatively you can initialize it with
1298 * #G_STATIC_PRIVATE_INIT.
1301 g_static_private_init (GStaticPrivate *private_key)
1303 private_key->index = 0;
1307 * g_static_private_get:
1308 * @private_key: a #GStaticPrivate
1310 * Works like g_private_get() only for a #GStaticPrivate.
1312 * This function works even if g_thread_init() has not yet been called.
1314 * Returns: the corresponding pointer
1317 g_static_private_get (GStaticPrivate *private_key)
1320 gpointer ret = NULL;
1322 array = g_private_get (&static_private_private);
1324 if (array && private_key->index != 0 && private_key->index <= array->len)
1326 GStaticPrivateNode *node;
1328 node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
1330 /* Deal with the possibility that the GStaticPrivate which used
1331 * to have this index got freed and the index got allocated to
1332 * a new one. In this case, the data in the node is stale, so
1333 * free it and return NULL.
1335 if (G_UNLIKELY (node->owner != private_key))
1338 node->destroy (node->data);
1339 node->destroy = NULL;
1350 * g_static_private_set:
1351 * @private_key: a #GStaticPrivate
1352 * @data: the new pointer
1353 * @notify: a function to be called with the pointer whenever the
1354 * current thread ends or sets this pointer again
1356 * Sets the pointer keyed to @private_key for the current thread and
1357 * the function @notify to be called with that pointer (%NULL or
1358 * non-%NULL), whenever the pointer is set again or whenever the
1359 * current thread ends.
1361 * This function works even if g_thread_init() has not yet been called.
1362 * If g_thread_init() is called later, the @data keyed to @private_key
1363 * will be inherited only by the main thread, i.e. the one that called
1366 * <note><para>@notify is used quite differently from @destructor in
1367 * g_private_new().</para></note>
1370 g_static_private_set (GStaticPrivate *private_key,
1372 GDestroyNotify notify)
1375 static guint next_index = 0;
1376 GStaticPrivateNode *node;
1378 if (!private_key->index)
1382 if (!private_key->index)
1384 if (g_thread_free_indices)
1386 private_key->index = GPOINTER_TO_UINT (g_thread_free_indices->data);
1387 g_thread_free_indices = g_slist_delete_link (g_thread_free_indices,
1388 g_thread_free_indices);
1391 private_key->index = ++next_index;
1394 G_UNLOCK (g_thread);
1397 array = g_private_get (&static_private_private);
1400 array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
1401 g_private_set (&static_private_private, array);
1403 if (private_key->index > array->len)
1404 g_array_set_size (array, private_key->index);
1406 node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
1409 node->destroy (node->data);
1412 node->destroy = notify;
1413 node->owner = private_key;
1417 * g_static_private_free:
1418 * @private_key: a #GStaticPrivate to be freed
1420 * Releases all resources allocated to @private_key.
1422 * You don't have to call this functions for a #GStaticPrivate with an
1423 * unbounded lifetime, i.e. objects declared 'static', but if you have
1424 * a #GStaticPrivate as a member of a structure and the structure is
1425 * freed, you should also free the #GStaticPrivate.
1428 g_static_private_free (GStaticPrivate *private_key)
1430 guint idx = private_key->index;
1435 private_key->index = 0;
1437 /* Freeing the per-thread data is deferred to either the
1438 * thread end or the next g_static_private_get() call for
1442 g_thread_free_indices = g_slist_prepend (g_thread_free_indices,
1443 GUINT_TO_POINTER (idx));
1444 G_UNLOCK (g_thread);
1447 /* GMutex {{{1 ------------------------------------------------------ */
1452 * Allocates and initializes a new #GMutex.
1454 * Returns: a newly allocated #GMutex. Use g_mutex_free() to free
1456 * Deprecated:3.32:GMutex can now be statically allocated, or embedded
1457 * in structures and initialised with g_mutex_init().
1464 mutex = g_slice_new (GMutex);
1465 g_mutex_init (mutex);
1474 * Destroys a @mutex that has been created with g_mutex_new().
1476 * Calling g_mutex_free() on a locked mutex may result
1477 * in undefined behaviour.
1479 * Deprecated:3.32:GMutex can now be statically allocated, or embedded
1480 * in structures and initialised with g_mutex_init().
1483 g_mutex_free (GMutex *mutex)
1485 g_mutex_clear (mutex);
1486 g_slice_free (GMutex, mutex);
1489 /* GCond {{{1 ------------------------------------------------------ */
1494 * Allocates and initializes a new #GCond.
1496 * Returns: a newly allocated #GCond. Free with g_cond_free()
1498 * Deprecated:3.32:GCond can now be statically allocated, or embedded
1499 * in structures and initialised with g_cond_init().
1506 cond = g_slice_new (GCond);
1516 * Destroys a #GCond that has been created with g_cond_new().
1518 * Calling g_cond_free() for a #GCond on which threads are
1519 * blocking leads to undefined behaviour.
1521 * Deprecated:3.32:GCond can now be statically allocated, or embedded
1522 * in structures and initialised with g_cond_init().
1525 g_cond_free (GCond *cond)
1527 g_cond_clear (cond);
1528 g_slice_free (GCond, cond);
1532 /* vim: set foldmethod=marker: */