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.
25 /* Prelude {{{1 ----------------------------------------------------------- */
28 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
29 * file for a list of people on the GLib Team. See the ChangeLog
30 * files for a list of changes. These files are distributed with
31 * GLib at ftp://ftp.gtk.org/pub/gtk/.
38 /* implement gthread.h's inline functions */
39 #define G_IMPLEMENT_INLINES 1
40 #define __G_THREAD_C__
44 #include "deprecated/gthread.h"
45 #include "gthreadprivate.h"
58 #endif /* G_OS_WIN32 */
65 #include "gtestutils.h"
71 * @short_description: portable support for threads, mutexes, locks,
72 * conditions and thread private data
73 * @see_also: #GThreadPool, #GAsyncQueue
75 * Threads act almost like processes, but unlike processes all threads
76 * of one process share the same memory. This is good, as it provides
77 * easy communication between the involved threads via this shared
78 * memory, and it is bad, because strange things (so called
79 * "Heisenbugs") might happen if the program is not carefully designed.
80 * In particular, due to the concurrent nature of threads, no
81 * assumptions on the order of execution of code running in different
82 * threads can be made, unless order is explicitly forced by the
83 * programmer through synchronization primitives.
85 * The aim of the thread-related functions in GLib is to provide a
86 * portable means for writing multi-threaded software. There are
87 * primitives for mutexes to protect the access to portions of memory
88 * (#GMutex, #GRecMutex and #GRWLock). There is a facility to use
89 * individual bits for locks (g_bit_lock()). There are primitives
90 * for condition variables to allow synchronization of threads (#GCond).
91 * There are primitives for thread-private data - data that every thread
92 * has a private instance of (#GPrivate, #GStaticPrivate). There are
93 * facilities for one-time initialization (#GOnce, g_once_init_enter()).
94 * Finally there are primitives to create and manage threads (#GThread).
96 * The threading system is initialized with g_thread_init(), which
97 * takes an optional custom thread implementation or %NULL for the
98 * default implementation. If you want to call g_thread_init() with a
99 * non-%NULL argument this must be done before executing any other GLib
100 * functions (except g_mem_set_vtable()). This is a requirement even if
101 * no threads are in fact ever created by the process.
103 * Calling g_thread_init() with a %NULL argument is somewhat more
104 * relaxed. You may call any other glib functions in the main thread
105 * before g_thread_init() as long as g_thread_init() is not called from
106 * a glib callback, or with any locks held. However, many libraries
107 * above glib does not support late initialization of threads, so doing
108 * this should be avoided if possible.
110 * Please note that since version 2.24 the GObject initialization
111 * function g_type_init() initializes threads (with a %NULL argument),
112 * so most applications, including those using GTK+ will run with
113 * threads enabled. If you want a special thread implementation, make
114 * sure you call g_thread_init() before g_type_init() is called.
116 * After calling g_thread_init(), GLib is completely thread safe (all
117 * global data is automatically locked), but individual data structure
118 * instances are not automatically locked for performance reasons. So,
119 * for example you must coordinate accesses to the same #GHashTable
120 * from multiple threads. The two notable exceptions from this rule
121 * are #GMainLoop and #GAsyncQueue, which <emphasis>are</emphasis>
122 * threadsafe and need no further application-level locking to be
123 * accessed from multiple threads.
127 * G_THREADS_IMPL_POSIX:
129 * This macro is defined if POSIX style threads are used.
133 * G_THREADS_IMPL_WIN32:
135 * This macro is defined if Windows style threads are used.
141 * This macro is defined, for backward compatibility, to indicate that
142 * GLib has been compiled with thread support. As of GLib 2.28, it is
146 /* G_LOCK Documentation {{{1 ---------------------------------------------- */
148 /* IMPLEMENTATION NOTE:
150 * G_LOCK_DEFINE and friends are convenience macros defined in
151 * gthread.h. Their documentation lives here.
156 * @name: the name of the lock.
158 * The %G_LOCK_* macros provide a convenient interface to #GStaticMutex
159 * with the advantage that they will expand to nothing in programs
160 * compiled against a thread-disabled GLib, saving code and memory
161 * there. #G_LOCK_DEFINE defines a lock. It can appear anywhere
162 * variable definitions may appear in programs, i.e. in the first block
163 * of a function or outside of functions. The @name parameter will be
164 * mangled to get the name of the #GStaticMutex. This means that you
165 * can use names of existing variables as the parameter - e.g. the name
166 * of the variable you intent to protect with the lock. Look at our
167 * <function>give_me_next_number()</function> example using the
171 * <title>Using the %G_LOCK_* convenience macros</title>
173 * G_LOCK_DEFINE (current_number);
176 * give_me_next_number (void)
178 * static int current_number = 0;
181 * G_LOCK (current_number);
182 * ret_val = current_number = calc_next_number (current_number);
183 * G_UNLOCK (current_number);
192 * G_LOCK_DEFINE_STATIC:
193 * @name: the name of the lock.
195 * This works like #G_LOCK_DEFINE, but it creates a static object.
200 * @name: the name of the lock.
202 * This declares a lock, that is defined with #G_LOCK_DEFINE in another
208 * @name: the name of the lock.
210 * Works like g_mutex_lock(), but for a lock defined with
216 * @name: the name of the lock.
217 * @Returns: %TRUE, if the lock could be locked.
219 * Works like g_mutex_trylock(), but for a lock defined with
225 * @name: the name of the lock.
227 * Works like g_mutex_unlock(), but for a lock defined with
231 /* GThreadError {{{1 ------------------------------------------------------- */
234 * @G_THREAD_ERROR_AGAIN: a thread couldn't be created due to resource
235 * shortage. Try again later.
237 * Possible errors of thread related functions.
243 * The error domain of the GLib thread subsystem.
246 g_thread_error_quark (void)
248 return g_quark_from_static_string ("g_thread_error");
251 /* Miscellaneous Structures {{{1 ------------------------------------------ */
252 typedef struct _GRealThread GRealThread;
256 /* Bit 0 protects private_data. To avoid deadlocks, do not block while
257 * holding this (particularly on the g_thread lock). */
258 volatile gint private_data_lock;
259 GArray *private_data;
262 GSystemThread system_thread;
265 #define LOCK_PRIVATE_DATA(self) g_bit_lock (&(self)->private_data_lock, 0)
266 #define UNLOCK_PRIVATE_DATA(self) g_bit_unlock (&(self)->private_data_lock, 0)
268 typedef struct _GStaticPrivateNode GStaticPrivateNode;
269 struct _GStaticPrivateNode
272 GDestroyNotify destroy;
275 static void g_thread_cleanup (gpointer data);
276 static guint64 gettime (void);
278 guint64 (*g_thread_gettime) (void) = gettime;
280 /* Global Variables {{{1 -------------------------------------------------- */
282 static GSystemThread zero_thread; /* This is initialized to all zero */
283 gboolean g_thread_use_default_impl = TRUE;
286 * g_thread_supported:
287 * @Returns: %TRUE, if the thread system is initialized.
289 * This function returns %TRUE if the thread system is initialized, and
290 * %FALSE if it is not.
292 * <note><para>This function is actually a macro. Apart from taking the
293 * address of it you can however use it as if it was a
294 * function.</para></note>
297 /* IMPLEMENTATION NOTE:
299 * g_thread_supported() is just returns g_threads_got_initialized
301 gboolean g_threads_got_initialized = FALSE;
304 /* Thread Implementation Virtual Function Table {{{1 ---------------------- */
305 /* Virtual Function Table Documentation {{{2 ------------------------------ */
308 * @mutex_new: virtual function pointer for g_mutex_new()
309 * @mutex_lock: virtual function pointer for g_mutex_lock()
310 * @mutex_trylock: virtual function pointer for g_mutex_trylock()
311 * @mutex_unlock: virtual function pointer for g_mutex_unlock()
312 * @mutex_free: virtual function pointer for g_mutex_free()
313 * @cond_new: virtual function pointer for g_cond_new()
314 * @cond_signal: virtual function pointer for g_cond_signal()
315 * @cond_broadcast: virtual function pointer for g_cond_broadcast()
316 * @cond_wait: virtual function pointer for g_cond_wait()
317 * @cond_timed_wait: virtual function pointer for g_cond_timed_wait()
318 * @cond_free: virtual function pointer for g_cond_free()
319 * @private_new: virtual function pointer for g_private_new()
320 * @private_get: virtual function pointer for g_private_get()
321 * @private_set: virtual function pointer for g_private_set()
322 * @thread_create: virtual function pointer for g_thread_create()
323 * @thread_yield: virtual function pointer for g_thread_yield()
324 * @thread_join: virtual function pointer for g_thread_join()
325 * @thread_exit: virtual function pointer for g_thread_exit()
326 * @thread_set_priority: virtual function pointer for
327 * g_thread_set_priority()
328 * @thread_self: virtual function pointer for g_thread_self()
329 * @thread_equal: used internally by recursive mutex locks and by some
332 * This function table is used by g_thread_init() to initialize the
333 * thread system. The functions in the table are directly used by their
334 * g_* prepended counterparts (described in this document). For
335 * example, if you call g_mutex_new() then mutex_new() from the table
336 * provided to g_thread_init() will be called.
338 * <note><para>Do not use this struct unless you know what you are
339 * doing.</para></note>
342 /* GMutex Virtual Functions {{{2 ------------------------------------------ */
347 * The #GMutex struct is an opaque data structure to represent a mutex
348 * (mutual exclusion). It can be used to protect data against shared
349 * access. Take for example the following function:
352 * <title>A function which will not work in a threaded environment</title>
355 * give_me_next_number (void)
357 * static int current_number = 0;
359 * /<!-- -->* now do a very complicated calculation to calculate the new
360 * * number, this might for example be a random number generator
362 * current_number = calc_next_number (current_number);
364 * return current_number;
369 * It is easy to see that this won't work in a multi-threaded
370 * application. There current_number must be protected against shared
371 * access. A first naive implementation would be:
374 * <title>The wrong way to write a thread-safe function</title>
377 * give_me_next_number (void)
379 * static int current_number = 0;
381 * static GMutex * mutex = NULL;
383 * if (!mutex) mutex = g_mutex_new (<!-- -->);
385 * g_mutex_lock (mutex);
386 * ret_val = current_number = calc_next_number (current_number);
387 * g_mutex_unlock (mutex);
394 * This looks like it would work, but there is a race condition while
395 * constructing the mutex and this code cannot work reliable. Please do
396 * not use such constructs in your own programs! One working solution
400 * <title>A correct thread-safe function</title>
402 * static GMutex *give_me_next_number_mutex = NULL;
404 * /<!-- -->* this function must be called before any call to
405 * * give_me_next_number(<!-- -->)
407 * * it must be called exactly once.
410 * init_give_me_next_number (void)
412 * g_assert (give_me_next_number_mutex == NULL);
413 * give_me_next_number_mutex = g_mutex_new (<!-- -->);
417 * give_me_next_number (void)
419 * static int current_number = 0;
422 * g_mutex_lock (give_me_next_number_mutex);
423 * ret_val = current_number = calc_next_number (current_number);
424 * g_mutex_unlock (give_me_next_number_mutex);
431 * A statically initialized #GMutex provides an even simpler and safer
435 * <title>Using a statically allocated mutex</title>
438 * give_me_next_number (void)
440 * static GMutex mutex = G_MUTEX_INIT;
441 * static int current_number = 0;
444 * g_mutex_lock (&mutex);
445 * ret_val = current_number = calc_next_number (current_number);
446 * g_mutex_unlock (&mutex);
453 * A #GMutex should only be accessed via <function>g_mutex_</function>
457 /* GCond Virtual Functions {{{2 ------------------------------------------ */
462 * The #GCond struct is an opaque data structure that represents a
463 * condition. Threads can block on a #GCond if they find a certain
464 * condition to be false. If other threads change the state of this
465 * condition they signal the #GCond, and that causes the waiting
466 * threads to be woken up.
470 * Using GCond to block a thread until a condition is satisfied
473 * GCond* data_cond = NULL; /<!-- -->* Must be initialized somewhere *<!-- -->/
474 * GMutex* data_mutex = NULL; /<!-- -->* Must be initialized somewhere *<!-- -->/
475 * gpointer current_data = NULL;
478 * push_data (gpointer data)
480 * g_mutex_lock (data_mutex);
481 * current_data = data;
482 * g_cond_signal (data_cond);
483 * g_mutex_unlock (data_mutex);
491 * g_mutex_lock (data_mutex);
492 * while (!current_data)
493 * g_cond_wait (data_cond, data_mutex);
494 * data = current_data;
495 * current_data = NULL;
496 * g_mutex_unlock (data_mutex);
503 * Whenever a thread calls pop_data() now, it will wait until
504 * current_data is non-%NULL, i.e. until some other thread
505 * has called push_data().
507 * <note><para>It is important to use the g_cond_wait() and
508 * g_cond_timed_wait() functions only inside a loop which checks for the
509 * condition to be true. It is not guaranteed that the waiting thread
510 * will find the condition fulfilled after it wakes up, even if the
511 * signaling thread left the condition in that state: another thread may
512 * have altered the condition before the waiting thread got the chance
513 * to be woken up, even if the condition itself is protected by a
514 * #GMutex, like above.</para></note>
516 * A #GCond should only be accessed via the following functions.
519 /* GPrivate Virtual Functions {{{2 --------------------------------------- */
525 * #GStaticPrivate is a better choice for most uses.
528 * The #GPrivate struct is an opaque data structure to represent a
529 * thread private data key. Threads can thereby obtain and set a
530 * pointer which is private to the current thread. Take our
531 * <function>give_me_next_number(<!-- -->)</function> example from
532 * above. Suppose we don't want <literal>current_number</literal> to be
533 * shared between the threads, but instead to be private to each thread.
534 * This can be done as follows:
537 * <title>Using GPrivate for per-thread data</title>
539 * GPrivate* current_number_key = NULL; /<!-- -->* Must be initialized somewhere
540 * with g_private_new (g_free); *<!-- -->/
543 * give_me_next_number (void)
545 * int *current_number = g_private_get (current_number_key);
547 * if (!current_number)
549 * current_number = g_new (int, 1);
550 * *current_number = 0;
551 * g_private_set (current_number_key, current_number);
554 * *current_number = calc_next_number (*current_number);
556 * return *current_number;
561 * Here the pointer belonging to the key
562 * <literal>current_number_key</literal> is read. If it is %NULL, it has
563 * not been set yet. Then get memory for an integer value, assign this
564 * memory to the pointer and write the pointer back. Now we have an
565 * integer value that is private to the current thread.
567 * The #GPrivate struct should only be accessed via the following
570 * <note><para>All of the <function>g_private_*</function> functions are
571 * actually macros. Apart from taking their addresses, you can however
572 * use them as if they were functions.</para></note>
575 /* GThread Virtual Functions {{{2 ---------------------------------------- */
579 * The #GThread struct represents a running thread. It has three public
580 * read-only members, but the underlying struct is bigger, so you must
581 * not copy this struct.
583 * <note><para>Resources for a joinable thread are not fully released
584 * until g_thread_join() is called for that thread.</para></note>
589 * @data: data passed to the thread.
590 * @Returns: the return value of the thread, which will be returned by
593 * Specifies the type of the @func functions passed to
594 * g_thread_create() or g_thread_create_full().
599 * @G_THREAD_PRIORITY_LOW: a priority lower than normal
600 * @G_THREAD_PRIORITY_NORMAL: the default priority
601 * @G_THREAD_PRIORITY_HIGH: a priority higher than normal
602 * @G_THREAD_PRIORITY_URGENT: the highest priority
604 * Deprecated:2.32: thread priorities no longer have any effect.
607 /* Local Data {{{1 -------------------------------------------------------- */
609 static GMutex g_once_mutex = G_MUTEX_INIT;
610 static GCond g_once_cond = G_COND_INIT;
611 static GPrivate g_thread_specific_private;
612 static GRealThread *g_thread_all_threads = NULL;
613 static GSList *g_thread_free_indices = NULL;
614 static GSList* g_once_init_list = NULL;
616 G_LOCK_DEFINE_STATIC (g_thread);
618 /* Initialisation {{{1 ---------------------------------------------------- */
622 * @vtable: a function table of type #GThreadFunctions, that provides
623 * the entry points to the thread system to be used. Since 2.32,
624 * this parameter is ignored and should always be %NULL
626 * If you use GLib from more than one thread, you must initialize the
627 * thread system by calling g_thread_init().
629 * Since version 2.24, calling g_thread_init() multiple times is allowed,
630 * but nothing happens except for the first call.
632 * Since version 2.32, GLib does not support custom thread implementations
633 * anymore and the @vtable parameter is ignored and you should pass %NULL.
635 * <note><para>g_thread_init() must not be called directly or indirectly
636 * in a callback from GLib. Also no mutexes may be currently locked while
637 * calling g_thread_init().</para></note>
639 * <note><para>To use g_thread_init() in your program, you have to link
640 * with the libraries that the command <command>pkg-config --libs
641 * gthread-2.0</command> outputs. This is not the case for all the
642 * other thread-related functions of GLib. Those can be used without
643 * having to link with the thread libraries.</para></note>
647 g_thread_init_glib (void)
649 static gboolean already_done;
650 GRealThread* main_thread;
657 /* We let the main thread (the one that calls g_thread_init) inherit
658 * the static_private data set before calling g_thread_init
660 main_thread = (GRealThread*) g_thread_self ();
662 /* setup the basic threading system */
663 g_threads_got_initialized = TRUE;
664 g_private_init (&g_thread_specific_private, g_thread_cleanup);
665 g_private_set (&g_thread_specific_private, main_thread);
666 g_system_thread_self (&main_thread->system_thread);
668 /* accomplish log system initialization to enable messaging */
669 _g_messages_thread_init_nomessage ();
672 /* The following sections implement: GOnce, GStaticMutex, GStaticRecMutex,
676 /* GOnce {{{1 ------------------------------------------------------------- */
680 * @status: the status of the #GOnce
681 * @retval: the value returned by the call to the function, if @status
682 * is %G_ONCE_STATUS_READY
684 * A #GOnce struct controls a one-time initialization function. Any
685 * one-time initialization function must have its own unique #GOnce
694 * A #GOnce must be initialized with this macro before it can be used.
698 * GOnce my_once = G_ONCE_INIT;
707 * @G_ONCE_STATUS_NOTCALLED: the function has not been called yet.
708 * @G_ONCE_STATUS_PROGRESS: the function call is currently in progress.
709 * @G_ONCE_STATUS_READY: the function has been called.
711 * The possible statuses of a one-time initialization function
712 * controlled by a #GOnce struct.
719 * @once: a #GOnce structure
720 * @func: the #GThreadFunc function associated to @once. This function
721 * is called only once, regardless of the number of times it and
722 * its associated #GOnce struct are passed to g_once().
723 * @arg: data to be passed to @func
725 * The first call to this routine by a process with a given #GOnce
726 * struct calls @func with the given argument. Thereafter, subsequent
727 * calls to g_once() with the same #GOnce struct do not call @func
728 * again, but return the stored result of the first call. On return
729 * from g_once(), the status of @once will be %G_ONCE_STATUS_READY.
731 * For example, a mutex or a thread-specific data key must be created
732 * exactly once. In a threaded environment, calling g_once() ensures
733 * that the initialization is serialized across multiple threads.
735 * <note><para>Calling g_once() recursively on the same #GOnce struct in
736 * @func will lead to a deadlock.</para></note>
741 * get_debug_flags (void)
743 * static GOnce my_once = G_ONCE_INIT;
745 * g_once (&my_once, parse_debug_flags, NULL);
747 * return my_once.retval;
755 g_once_impl (GOnce *once,
759 g_mutex_lock (&g_once_mutex);
761 while (once->status == G_ONCE_STATUS_PROGRESS)
762 g_cond_wait (&g_once_cond, &g_once_mutex);
764 if (once->status != G_ONCE_STATUS_READY)
766 once->status = G_ONCE_STATUS_PROGRESS;
767 g_mutex_unlock (&g_once_mutex);
769 once->retval = func (arg);
771 g_mutex_lock (&g_once_mutex);
772 once->status = G_ONCE_STATUS_READY;
773 g_cond_broadcast (&g_once_cond);
776 g_mutex_unlock (&g_once_mutex);
783 * @value_location: location of a static initializable variable
785 * @Returns: %TRUE if the initialization section should be entered,
786 * %FALSE and blocks otherwise
788 * Function to be called when starting a critical initialization
789 * section. The argument @value_location must point to a static
790 * 0-initialized variable that will be set to a value other than 0 at
791 * the end of the initialization section. In combination with
792 * g_once_init_leave() and the unique address @value_location, it can
793 * be ensured that an initialization section will be executed only once
794 * during a program's life time, and that concurrent threads are
795 * blocked until initialization completed. To be used in constructs
800 * static gsize initialization_value = 0;
802 * if (g_once_init_enter (&initialization_value))
804 * gsize setup_value = 42; /<!-- -->* initialization code here *<!-- -->/
806 * g_once_init_leave (&initialization_value, setup_value);
809 * /<!-- -->* use initialization_value here *<!-- -->/
816 g_once_init_enter_impl (volatile gsize *value_location)
818 gboolean need_init = FALSE;
819 g_mutex_lock (&g_once_mutex);
820 if (g_atomic_pointer_get (value_location) == NULL)
822 if (!g_slist_find (g_once_init_list, (void*) value_location))
825 g_once_init_list = g_slist_prepend (g_once_init_list, (void*) value_location);
829 g_cond_wait (&g_once_cond, &g_once_mutex);
830 while (g_slist_find (g_once_init_list, (void*) value_location));
832 g_mutex_unlock (&g_once_mutex);
838 * @value_location: location of a static initializable variable
840 * @initialization_value: new non-0 value for *@value_location.
842 * Counterpart to g_once_init_enter(). Expects a location of a static
843 * 0-initialized initialization variable, and an initialization value
844 * other than 0. Sets the variable to the initialization value, and
845 * releases concurrent threads blocking in g_once_init_enter() on this
846 * initialization variable.
851 g_once_init_leave (volatile gsize *value_location,
852 gsize initialization_value)
854 g_return_if_fail (g_atomic_pointer_get (value_location) == NULL);
855 g_return_if_fail (initialization_value != 0);
856 g_return_if_fail (g_once_init_list != NULL);
858 g_atomic_pointer_set (value_location, initialization_value);
859 g_mutex_lock (&g_once_mutex);
860 g_once_init_list = g_slist_remove (g_once_init_list, (void*) value_location);
861 g_cond_broadcast (&g_once_cond);
862 g_mutex_unlock (&g_once_mutex);
865 /* GStaticMutex {{{1 ------------------------------------------------------ */
870 * A #GStaticMutex works like a #GMutex.
872 * Prior to GLib 2.32, GStaticMutex had the significant advantage
873 * that it doesn't need to be created at run-time, but can be defined
874 * at compile-time. Since 2.32, #GMutex can be statically allocated
875 * as well, and GStaticMutex has been deprecated.
877 * Here is a version of our give_me_next_number() example using
882 * Using <structname>GStaticMutex</structname>
883 * to simplify thread-safe programming
887 * give_me_next_number (void)
889 * static int current_number = 0;
891 * static GStaticMutex mutex = G_STATIC_MUTEX_INIT;
893 * g_static_mutex_lock (&mutex);
894 * ret_val = current_number = calc_next_number (current_number);
895 * g_static_mutex_unlock (&mutex);
902 * Sometimes you would like to dynamically create a mutex. If you don't
903 * want to require prior calling to g_thread_init(), because your code
904 * should also be usable in non-threaded programs, you are not able to
905 * use g_mutex_new() and thus #GMutex, as that requires a prior call to
906 * g_thread_init(). In theses cases you can also use a #GStaticMutex.
907 * It must be initialized with g_static_mutex_init() before using it
908 * and freed with with g_static_mutex_free() when not needed anymore to
909 * free up any allocated resources.
911 * Even though #GStaticMutex is not opaque, it should only be used with
912 * the following functions, as it is defined differently on different
915 * All of the <function>g_static_mutex_*</function> functions apart
916 * from <function>g_static_mutex_get_mutex</function> can also be used
917 * even if g_thread_init() has not yet been called. Then they do
918 * nothing, apart from <function>g_static_mutex_trylock</function>,
919 * which does nothing but returning %TRUE.
921 * <note><para>All of the <function>g_static_mutex_*</function>
922 * functions are actually macros. Apart from taking their addresses, you
923 * can however use them as if they were functions.</para></note>
927 * G_STATIC_MUTEX_INIT:
929 * A #GStaticMutex must be initialized with this macro, before it can
930 * be used. This macro can used be to initialize a variable, but it
931 * cannot be assigned to a variable. In that case you have to use
932 * g_static_mutex_init().
935 * GStaticMutex my_mutex = G_STATIC_MUTEX_INIT;
940 * g_static_mutex_init:
941 * @mutex: a #GStaticMutex to be initialized.
943 * Initializes @mutex.
944 * Alternatively you can initialize it with #G_STATIC_MUTEX_INIT.
946 * Deprecated: 2.32: Use g_mutex_init()
949 g_static_mutex_init (GStaticMutex *mutex)
951 static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
953 g_return_if_fail (mutex);
958 /* IMPLEMENTATION NOTE:
960 * On some platforms a GStaticMutex is actually a normal GMutex stored
961 * inside of a structure instead of being allocated dynamically. We can
962 * only do this for platforms on which we know, in advance, how to
963 * allocate (size) and initialise (value) that memory.
965 * On other platforms, a GStaticMutex is nothing more than a pointer to
966 * a GMutex. In that case, the first access we make to the static mutex
967 * must first allocate the normal GMutex and store it into the pointer.
969 * configure.ac writes macros into glibconfig.h to determine if
970 * g_static_mutex_get_mutex() accesses the structure in memory directly
971 * (on platforms where we are able to do that) or if it ends up here,
972 * where we may have to allocate the GMutex before returning it.
976 * g_static_mutex_get_mutex:
977 * @mutex: a #GStaticMutex.
978 * @Returns: the #GMutex corresponding to @mutex.
980 * For some operations (like g_cond_wait()) you must have a #GMutex
981 * instead of a #GStaticMutex. This function will return the
982 * corresponding #GMutex for @mutex.
984 * Deprecated: 2.32: Just use a #GMutex
987 g_static_mutex_get_mutex_impl (GMutex** mutex)
991 if (!g_thread_supported ())
994 result = g_atomic_pointer_get (mutex);
998 g_mutex_lock (&g_once_mutex);
1003 result = g_mutex_new ();
1004 g_atomic_pointer_set (mutex, result);
1007 g_mutex_unlock (&g_once_mutex);
1013 /* IMPLEMENTATION NOTE:
1015 * g_static_mutex_lock(), g_static_mutex_trylock() and
1016 * g_static_mutex_unlock() are all preprocessor macros that wrap the
1017 * corresponding g_mutex_*() function around a call to
1018 * g_static_mutex_get_mutex().
1022 * g_static_mutex_lock:
1023 * @mutex: a #GStaticMutex.
1025 * Works like g_mutex_lock(), but for a #GStaticMutex.
1027 * Deprecated: 2.32: Use g_mutex_lock()
1031 * g_static_mutex_trylock:
1032 * @mutex: a #GStaticMutex.
1033 * @Returns: %TRUE, if the #GStaticMutex could be locked.
1035 * Works like g_mutex_trylock(), but for a #GStaticMutex.
1037 * Deprecated: 2.32: Use g_mutex_trylock()
1041 * g_static_mutex_unlock:
1042 * @mutex: a #GStaticMutex.
1044 * Works like g_mutex_unlock(), but for a #GStaticMutex.
1046 * Deprecated: 2.32: Use g_mutex_unlock()
1050 * g_static_mutex_free:
1051 * @mutex: a #GStaticMutex to be freed.
1053 * Releases all resources allocated to @mutex.
1055 * You don't have to call this functions for a #GStaticMutex with an
1056 * unbounded lifetime, i.e. objects declared 'static', but if you have
1057 * a #GStaticMutex as a member of a structure and the structure is
1058 * freed, you should also free the #GStaticMutex.
1060 * <note><para>Calling g_static_mutex_free() on a locked mutex may
1061 * result in undefined behaviour.</para></note>
1063 * Deprecated: 2.32: Use g_mutex_free()
1066 g_static_mutex_free (GStaticMutex* mutex)
1068 GMutex **runtime_mutex;
1070 g_return_if_fail (mutex);
1072 /* The runtime_mutex is the first (or only) member of GStaticMutex,
1073 * see both versions (of glibconfig.h) in configure.ac. Note, that
1074 * this variable is NULL, if g_thread_init() hasn't been called or
1075 * if we're using the default thread implementation and it provides
1076 * static mutexes. */
1077 runtime_mutex = ((GMutex**)mutex);
1080 g_mutex_free (*runtime_mutex);
1082 *runtime_mutex = NULL;
1085 /* ------------------------------------------------------------------------ */
1090 * A #GStaticRecMutex works like a #GStaticMutex, but it can be locked
1091 * multiple times by one thread. If you enter it n times, you have to
1092 * unlock it n times again to let other threads lock it. An exception
1093 * is the function g_static_rec_mutex_unlock_full(): that allows you to
1094 * unlock a #GStaticRecMutex completely returning the depth, (i.e. the
1095 * number of times this mutex was locked). The depth can later be used
1096 * to restore the state of the #GStaticRecMutex by calling
1097 * g_static_rec_mutex_lock_full(). In GLib 2.32, #GStaticRecMutex has
1098 * been deprecated in favor of #GRecMutex.
1100 * Even though #GStaticRecMutex is not opaque, it should only be used
1101 * with the following functions.
1103 * All of the <function>g_static_rec_mutex_*</function> functions can
1104 * be used even if g_thread_init() has not been called. Then they do
1105 * nothing, apart from <function>g_static_rec_mutex_trylock</function>,
1106 * which does nothing but returning %TRUE.
1110 * G_STATIC_REC_MUTEX_INIT:
1112 * A #GStaticRecMutex must be initialized with this macro before it can
1113 * be used. This macro can used be to initialize a variable, but it
1114 * cannot be assigned to a variable. In that case you have to use
1115 * g_static_rec_mutex_init().
1118 * GStaticRecMutex my_mutex = G_STATIC_REC_MUTEX_INIT;
1123 * g_static_rec_mutex_init:
1124 * @mutex: a #GStaticRecMutex to be initialized.
1126 * A #GStaticRecMutex must be initialized with this function before it
1127 * can be used. Alternatively you can initialize it with
1128 * #G_STATIC_REC_MUTEX_INIT.
1130 * Deprecated: 2.32: Use g_rec_mutex_init()
1133 g_static_rec_mutex_init (GStaticRecMutex *mutex)
1135 static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
1137 g_return_if_fail (mutex);
1139 *mutex = init_mutex;
1143 * g_static_rec_mutex_lock:
1144 * @mutex: a #GStaticRecMutex to lock.
1146 * Locks @mutex. If @mutex is already locked by another thread, the
1147 * current thread will block until @mutex is unlocked by the other
1148 * thread. If @mutex is already locked by the calling thread, this
1149 * functions increases the depth of @mutex and returns immediately.
1151 * Deprecated: 2.32: Use g_rec_mutex_lock()
1154 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
1158 g_return_if_fail (mutex);
1160 if (!g_thread_supported ())
1163 g_system_thread_self (&self);
1165 if (g_system_thread_equal (&self, &mutex->owner))
1170 g_static_mutex_lock (&mutex->mutex);
1171 g_system_thread_assign (mutex->owner, self);
1176 * g_static_rec_mutex_trylock:
1177 * @mutex: a #GStaticRecMutex to lock.
1178 * @Returns: %TRUE, if @mutex could be locked.
1180 * Tries to lock @mutex. If @mutex is already locked by another thread,
1181 * it immediately returns %FALSE. Otherwise it locks @mutex and returns
1182 * %TRUE. If @mutex is already locked by the calling thread, this
1183 * functions increases the depth of @mutex and immediately returns
1186 * Deprecated: 2.32: Use g_rec_mutex_trylock()
1189 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
1193 g_return_val_if_fail (mutex, FALSE);
1195 if (!g_thread_supported ())
1198 g_system_thread_self (&self);
1200 if (g_system_thread_equal (&self, &mutex->owner))
1206 if (!g_static_mutex_trylock (&mutex->mutex))
1209 g_system_thread_assign (mutex->owner, self);
1215 * g_static_rec_mutex_unlock:
1216 * @mutex: a #GStaticRecMutex to unlock.
1218 * Unlocks @mutex. Another thread will be allowed to lock @mutex only
1219 * when it has been unlocked as many times as it had been locked
1220 * before. If @mutex is completely unlocked and another thread is
1221 * blocked in a g_static_rec_mutex_lock() call for @mutex, it will be
1222 * woken and can lock @mutex itself.
1224 * Deprecated: 2.32: Use g_rec_mutex_unlock()
1227 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
1229 g_return_if_fail (mutex);
1231 if (!g_thread_supported ())
1234 if (mutex->depth > 1)
1239 g_system_thread_assign (mutex->owner, zero_thread);
1240 g_static_mutex_unlock (&mutex->mutex);
1244 * g_static_rec_mutex_lock_full:
1245 * @mutex: a #GStaticRecMutex to lock.
1246 * @depth: number of times this mutex has to be unlocked to be
1247 * completely unlocked.
1249 * Works like calling g_static_rec_mutex_lock() for @mutex @depth times.
1251 * Deprecated: 2.32: Use g_rec_mutex_lock()
1254 g_static_rec_mutex_lock_full (GStaticRecMutex *mutex,
1258 g_return_if_fail (mutex);
1260 if (!g_thread_supported ())
1266 g_system_thread_self (&self);
1268 if (g_system_thread_equal (&self, &mutex->owner))
1270 mutex->depth += depth;
1273 g_static_mutex_lock (&mutex->mutex);
1274 g_system_thread_assign (mutex->owner, self);
1275 mutex->depth = depth;
1279 * g_static_rec_mutex_unlock_full:
1280 * @mutex: a #GStaticRecMutex to completely unlock.
1281 * @Returns: number of times @mutex has been locked by the current
1284 * Completely unlocks @mutex. If another thread is blocked in a
1285 * g_static_rec_mutex_lock() call for @mutex, it will be woken and can
1286 * lock @mutex itself. This function returns the number of times that
1287 * @mutex has been locked by the current thread. To restore the state
1288 * before the call to g_static_rec_mutex_unlock_full() you can call
1289 * g_static_rec_mutex_lock_full() with the depth returned by this
1292 * Deprecated: 2.32: Use g_rec_mutex_unlock()
1295 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
1299 g_return_val_if_fail (mutex, 0);
1301 if (!g_thread_supported ())
1304 depth = mutex->depth;
1306 g_system_thread_assign (mutex->owner, zero_thread);
1308 g_static_mutex_unlock (&mutex->mutex);
1314 * g_static_rec_mutex_free:
1315 * @mutex: a #GStaticRecMutex to be freed.
1317 * Releases all resources allocated to a #GStaticRecMutex.
1319 * You don't have to call this functions for a #GStaticRecMutex with an
1320 * unbounded lifetime, i.e. objects declared 'static', but if you have
1321 * a #GStaticRecMutex as a member of a structure and the structure is
1322 * freed, you should also free the #GStaticRecMutex.
1324 * Deprecated: 2.32: Use g_rec_mutex_clear()
1327 g_static_rec_mutex_free (GStaticRecMutex *mutex)
1329 g_return_if_fail (mutex);
1331 g_static_mutex_free (&mutex->mutex);
1334 /* GStaticPrivate {{{1 ---------------------------------------------------- */
1339 * A #GStaticPrivate works almost like a #GPrivate, but it has one
1340 * significant advantage. It doesn't need to be created at run-time
1341 * like a #GPrivate, but can be defined at compile-time. This is
1342 * similar to the difference between #GMutex and #GStaticMutex. Now
1343 * look at our <function>give_me_next_number()</function> example with
1347 * <title>Using GStaticPrivate for per-thread data</title>
1350 * give_me_next_number (<!-- -->)
1352 * static GStaticPrivate current_number_key = G_STATIC_PRIVATE_INIT;
1353 * int *current_number = g_static_private_get (&current_number_key);
1355 * if (!current_number)
1357 * current_number = g_new (int,1);
1358 * *current_number = 0;
1359 * g_static_private_set (&current_number_key, current_number, g_free);
1362 * *current_number = calc_next_number (*current_number);
1364 * return *current_number;
1371 * G_STATIC_PRIVATE_INIT:
1373 * Every #GStaticPrivate must be initialized with this macro, before it
1377 * GStaticPrivate my_private = G_STATIC_PRIVATE_INIT;
1382 * g_static_private_init:
1383 * @private_key: a #GStaticPrivate to be initialized.
1385 * Initializes @private_key. Alternatively you can initialize it with
1386 * #G_STATIC_PRIVATE_INIT.
1389 g_static_private_init (GStaticPrivate *private_key)
1391 private_key->index = 0;
1395 * g_static_private_get:
1396 * @private_key: a #GStaticPrivate.
1397 * @Returns: the corresponding pointer.
1399 * Works like g_private_get() only for a #GStaticPrivate.
1401 * This function works even if g_thread_init() has not yet been called.
1404 g_static_private_get (GStaticPrivate *private_key)
1406 GRealThread *self = (GRealThread*) g_thread_self ();
1408 gpointer ret = NULL;
1410 LOCK_PRIVATE_DATA (self);
1412 array = self->private_data;
1414 if (array && private_key->index != 0 && private_key->index <= array->len)
1415 ret = g_array_index (array, GStaticPrivateNode,
1416 private_key->index - 1).data;
1418 UNLOCK_PRIVATE_DATA (self);
1423 * g_static_private_set:
1424 * @private_key: a #GStaticPrivate.
1425 * @data: the new pointer.
1426 * @notify: a function to be called with the pointer whenever the
1427 * current thread ends or sets this pointer again.
1429 * Sets the pointer keyed to @private_key for the current thread and
1430 * the function @notify to be called with that pointer (%NULL or
1431 * non-%NULL), whenever the pointer is set again or whenever the
1432 * current thread ends.
1434 * This function works even if g_thread_init() has not yet been called.
1435 * If g_thread_init() is called later, the @data keyed to @private_key
1436 * will be inherited only by the main thread, i.e. the one that called
1439 * <note><para>@notify is used quite differently from @destructor in
1440 * g_private_new().</para></note>
1443 g_static_private_set (GStaticPrivate *private_key,
1445 GDestroyNotify notify)
1447 GRealThread *self = (GRealThread*) g_thread_self ();
1449 static guint next_index = 0;
1450 GStaticPrivateNode *node;
1451 gpointer ddata = NULL;
1452 GDestroyNotify ddestroy = NULL;
1454 if (!private_key->index)
1458 if (!private_key->index)
1460 if (g_thread_free_indices)
1462 private_key->index =
1463 GPOINTER_TO_UINT (g_thread_free_indices->data);
1464 g_thread_free_indices =
1465 g_slist_delete_link (g_thread_free_indices,
1466 g_thread_free_indices);
1469 private_key->index = ++next_index;
1472 G_UNLOCK (g_thread);
1475 LOCK_PRIVATE_DATA (self);
1477 array = self->private_data;
1480 array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
1481 self->private_data = array;
1484 if (private_key->index > array->len)
1485 g_array_set_size (array, private_key->index);
1487 node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
1490 ddestroy = node->destroy;
1493 node->destroy = notify;
1495 UNLOCK_PRIVATE_DATA (self);
1502 * g_static_private_free:
1503 * @private_key: a #GStaticPrivate to be freed.
1505 * Releases all resources allocated to @private_key.
1507 * You don't have to call this functions for a #GStaticPrivate with an
1508 * unbounded lifetime, i.e. objects declared 'static', but if you have
1509 * a #GStaticPrivate as a member of a structure and the structure is
1510 * freed, you should also free the #GStaticPrivate.
1513 g_static_private_free (GStaticPrivate *private_key)
1515 guint idx = private_key->index;
1516 GRealThread *thread, *next;
1517 GArray *garbage = NULL;
1522 private_key->index = 0;
1526 thread = g_thread_all_threads;
1528 for (thread = g_thread_all_threads; thread; thread = next)
1532 next = thread->next;
1534 LOCK_PRIVATE_DATA (thread);
1536 array = thread->private_data;
1538 if (array && idx <= array->len)
1540 GStaticPrivateNode *node = &g_array_index (array,
1543 gpointer ddata = node->data;
1544 GDestroyNotify ddestroy = node->destroy;
1547 node->destroy = NULL;
1551 /* defer non-trivial destruction til after we've finished
1552 * iterating, since we must continue to hold the lock */
1553 if (garbage == NULL)
1554 garbage = g_array_new (FALSE, TRUE,
1555 sizeof (GStaticPrivateNode));
1557 g_array_set_size (garbage, garbage->len + 1);
1559 node = &g_array_index (garbage, GStaticPrivateNode,
1562 node->destroy = ddestroy;
1566 UNLOCK_PRIVATE_DATA (thread);
1568 g_thread_free_indices = g_slist_prepend (g_thread_free_indices,
1569 GUINT_TO_POINTER (idx));
1570 G_UNLOCK (g_thread);
1576 for (i = 0; i < garbage->len; i++)
1578 GStaticPrivateNode *node;
1580 node = &g_array_index (garbage, GStaticPrivateNode, i);
1581 node->destroy (node->data);
1584 g_array_free (garbage, TRUE);
1588 /* GThread Extra Functions {{{1 ------------------------------------------- */
1590 g_thread_cleanup (gpointer data)
1594 GRealThread* thread = data;
1597 LOCK_PRIVATE_DATA (thread);
1598 array = thread->private_data;
1599 thread->private_data = NULL;
1600 UNLOCK_PRIVATE_DATA (thread);
1606 for (i = 0; i < array->len; i++ )
1608 GStaticPrivateNode *node =
1609 &g_array_index (array, GStaticPrivateNode, i);
1611 node->destroy (node->data);
1613 g_array_free (array, TRUE);
1616 /* We only free the thread structure, if it isn't joinable. If
1617 it is, the structure is freed in g_thread_join */
1618 if (!thread->thread.joinable)
1623 for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
1630 g_thread_all_threads = t->next;
1634 G_UNLOCK (g_thread);
1636 /* Just to make sure, this isn't used any more */
1637 g_system_thread_assign (thread->system_thread, zero_thread);
1643 #define G_NSEC_PER_SEC 1000000000
1648 return g_get_monotonic_time () * 1000;
1652 g_thread_create_proxy (gpointer data)
1654 GRealThread* thread = data;
1658 /* This has to happen before G_LOCK, as that might call g_thread_self */
1659 g_private_set (&g_thread_specific_private, data);
1661 /* the lock makes sure, that thread->system_thread is written,
1662 before thread->thread.func is called. See g_thread_create. */
1664 G_UNLOCK (g_thread);
1666 thread->retval = thread->thread.func (thread->thread.data);
1673 * @func: a function to execute in the new thread
1674 * @data: an argument to supply to the new thread
1675 * @joinable: should this thread be joinable?
1676 * @error: return location for error, or %NULL
1678 * This function creates a new thread.
1680 * If @joinable is %TRUE, you can wait for this threads termination
1681 * calling g_thread_join(). Otherwise the thread will just disappear
1682 * when it terminates.
1684 * The new thread executes the function @func with the argument @data.
1685 * If the thread was created successfully, it is returned.
1687 * @error can be %NULL to ignore errors, or non-%NULL to report errors.
1688 * The error is set, if and only if the function returns %NULL.
1690 * Returns: the new #GThread on success
1693 g_thread_create (GThreadFunc func,
1698 return g_thread_create_with_stack_size (func, data, joinable, 0, error);
1702 * g_thread_create_with_stack_size:
1703 * @func: a function to execute in the new thread.
1704 * @data: an argument to supply to the new thread.
1705 * @joinable: should this thread be joinable?
1706 * @stack_size: a stack size for the new thread.
1707 * @error: return location for error.
1708 * @Returns: the new #GThread on success.
1710 * This function creates a new thread. If the underlying thread
1711 * implementation supports it, the thread gets a stack size of
1712 * @stack_size or the default value for the current platform, if
1715 * If @joinable is %TRUE, you can wait for this threads termination
1716 * calling g_thread_join(). Otherwise the thread will just disappear
1717 * when it terminates.
1719 * The new thread executes the function @func with the argument @data.
1720 * If the thread was created successfully, it is returned.
1722 * @error can be %NULL to ignore errors, or non-%NULL to report errors.
1723 * The error is set, if and only if the function returns %NULL.
1726 * Only use g_thread_create_with_stack_size() if you really can't use
1727 * g_thread_create() instead. g_thread_create() does not take
1728 * @stack_size, as it should only be used in cases in which it is
1733 g_thread_create_with_stack_size (GThreadFunc func,
1739 GRealThread* result;
1740 GError *local_error = NULL;
1741 g_return_val_if_fail (func, NULL);
1743 result = g_new0 (GRealThread, 1);
1745 result->thread.joinable = joinable;
1746 result->thread.func = func;
1747 result->thread.data = data;
1748 result->private_data = NULL;
1750 g_system_thread_create (g_thread_create_proxy, result,
1751 stack_size, joinable,
1752 &result->system_thread, &local_error);
1755 result->next = g_thread_all_threads;
1756 g_thread_all_threads = result;
1758 G_UNLOCK (g_thread);
1762 g_propagate_error (error, local_error);
1767 return (GThread*) result;
1771 * g_thread_create_full:
1772 * @func: a function to execute in the new thread.
1773 * @data: an argument to supply to the new thread.
1774 * @stack_size: a stack size for the new thread.
1775 * @joinable: should this thread be joinable?
1777 * @priority: ignored
1778 * @error: return location for error.
1779 * @Returns: the new #GThread on success.
1781 * This function creates a new thread.
1783 * Deprecated:2.32: The @bound and @priority arguments are now ignored.
1784 * Use g_thread_create() or g_thread_create_with_stack_size() instead.
1787 g_thread_create_full (GThreadFunc func,
1792 GThreadPriority priority,
1795 return g_thread_create_with_stack_size (func, data, joinable, stack_size, error);
1800 * @retval: the return value of this thread.
1802 * Exits the current thread. If another thread is waiting for that
1803 * thread using g_thread_join() and the current thread is joinable, the
1804 * waiting thread will be woken up and get @retval as the return value
1805 * of g_thread_join(). If the current thread is not joinable, @retval
1806 * is ignored. Calling
1809 * g_thread_exit (retval);
1812 * is equivalent to returning @retval from the function @func, as given
1813 * to g_thread_create().
1815 * <note><para>Never call g_thread_exit() from within a thread of a
1816 * #GThreadPool, as that will mess up the bookkeeping and lead to funny
1817 * and unwanted results.</para></note>
1820 g_thread_exit (gpointer retval)
1822 GRealThread* real = (GRealThread*) g_thread_self ();
1823 real->retval = retval;
1825 g_system_thread_exit ();
1830 * @thread: a #GThread to be waited for.
1831 * @Returns: the return value of the thread.
1833 * Waits until @thread finishes, i.e. the function @func, as given to
1834 * g_thread_create(), returns or g_thread_exit() is called by @thread.
1835 * All resources of @thread including the #GThread struct are released.
1836 * @thread must have been created with @joinable=%TRUE in
1837 * g_thread_create(). The value returned by @func or given to
1838 * g_thread_exit() by @thread is returned by this function.
1841 g_thread_join (GThread* thread)
1843 GRealThread* real = (GRealThread*) thread;
1847 g_return_val_if_fail (thread, NULL);
1848 g_return_val_if_fail (thread->joinable, NULL);
1849 g_return_val_if_fail (!g_system_thread_equal (&real->system_thread, &zero_thread), NULL);
1851 g_system_thread_join (&real->system_thread);
1853 retval = real->retval;
1856 for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
1858 if (t == (GRealThread*) thread)
1863 g_thread_all_threads = t->next;
1867 G_UNLOCK (g_thread);
1869 /* Just to make sure, this isn't used any more */
1870 thread->joinable = 0;
1871 g_system_thread_assign (real->system_thread, zero_thread);
1873 /* the thread structure for non-joinable threads is freed upon
1874 thread end. We free the memory here. This will leave a loose end,
1875 if a joinable thread is not joined. */
1883 * g_thread_set_priority:
1884 * @thread: a #GThread.
1885 * @priority: ignored
1887 * This function does nothing.
1889 * Deprecated:2.32: Thread priorities no longer have any effect.
1892 g_thread_set_priority (GThread *thread,
1893 GThreadPriority priority)
1899 * @Returns: the current thread.
1901 * This functions returns the #GThread corresponding to the calling
1905 g_thread_self (void)
1907 GRealThread* thread = g_private_get (&g_thread_specific_private);
1911 /* If no thread data is available, provide and set one. This
1912 can happen for the main thread and for threads, that are not
1914 thread = g_new0 (GRealThread, 1);
1915 thread->thread.joinable = FALSE; /* This is a save guess */
1916 thread->thread.func = NULL;
1917 thread->thread.data = NULL;
1918 thread->private_data = NULL;
1920 g_system_thread_self (&thread->system_thread);
1922 g_private_set (&g_thread_specific_private, thread);
1925 thread->next = g_thread_all_threads;
1926 g_thread_all_threads = thread;
1927 G_UNLOCK (g_thread);
1930 return (GThread*)thread;
1933 /* GStaticRWLock {{{1 ----------------------------------------------------- */
1938 * The #GStaticRWLock struct represents a read-write lock. A read-write
1939 * lock can be used for protecting data that some portions of code only
1940 * read from, while others also write. In such situations it is
1941 * desirable that several readers can read at once, whereas of course
1942 * only one writer may write at a time. Take a look at the following
1946 * <title>An array with access functions</title>
1948 * GStaticRWLock rwlock = G_STATIC_RW_LOCK_INIT;
1952 * my_array_get (guint index)
1954 * gpointer retval = NULL;
1959 * g_static_rw_lock_reader_lock (&rwlock);
1960 * if (index < array->len)
1961 * retval = g_ptr_array_index (array, index);
1962 * g_static_rw_lock_reader_unlock (&rwlock);
1968 * my_array_set (guint index, gpointer data)
1970 * g_static_rw_lock_writer_lock (&rwlock);
1973 * array = g_ptr_array_new (<!-- -->);
1975 * if (index >= array->len)
1976 * g_ptr_array_set_size (array, index+1);
1977 * g_ptr_array_index (array, index) = data;
1979 * g_static_rw_lock_writer_unlock (&rwlock);
1984 * This example shows an array which can be accessed by many readers
1985 * (the <function>my_array_get()</function> function) simultaneously,
1986 * whereas the writers (the <function>my_array_set()</function>
1987 * function) will only be allowed once at a time and only if no readers
1988 * currently access the array. This is because of the potentially
1989 * dangerous resizing of the array. Using these functions is fully
1990 * multi-thread safe now.
1992 * Most of the time, writers should have precedence over readers. That
1993 * means, for this implementation, that as soon as a writer wants to
1994 * lock the data, no other reader is allowed to lock the data, whereas,
1995 * of course, the readers that already have locked the data are allowed
1996 * to finish their operation. As soon as the last reader unlocks the
1997 * data, the writer will lock it.
1999 * Even though #GStaticRWLock is not opaque, it should only be used
2000 * with the following functions.
2002 * All of the <function>g_static_rw_lock_*</function> functions can be
2003 * used even if g_thread_init() has not been called. Then they do
2004 * nothing, apart from <function>g_static_rw_lock_*_trylock</function>,
2005 * which does nothing but returning %TRUE.
2007 * <note><para>A read-write lock has a higher overhead than a mutex. For
2008 * example, both g_static_rw_lock_reader_lock() and
2009 * g_static_rw_lock_reader_unlock() have to lock and unlock a
2010 * #GStaticMutex, so it takes at least twice the time to lock and unlock
2011 * a #GStaticRWLock that it does to lock and unlock a #GStaticMutex. So
2012 * only data structures that are accessed by multiple readers, and which
2013 * keep the lock for a considerable time justify a #GStaticRWLock. The
2014 * above example most probably would fare better with a
2015 * #GStaticMutex.</para></note>
2017 * Deprecated: 2.32: Use a #GRWLock instead
2021 * G_STATIC_RW_LOCK_INIT:
2023 * A #GStaticRWLock must be initialized with this macro before it can
2024 * be used. This macro can used be to initialize a variable, but it
2025 * cannot be assigned to a variable. In that case you have to use
2026 * g_static_rw_lock_init().
2029 * GStaticRWLock my_lock = G_STATIC_RW_LOCK_INIT;
2034 * g_static_rw_lock_init:
2035 * @lock: a #GStaticRWLock to be initialized.
2037 * A #GStaticRWLock must be initialized with this function before it
2038 * can be used. Alternatively you can initialize it with
2039 * #G_STATIC_RW_LOCK_INIT.
2041 * Deprecated: 2.32: Use g_rw_lock_init() instead
2044 g_static_rw_lock_init (GStaticRWLock* lock)
2046 static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
2048 g_return_if_fail (lock);
2054 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
2057 *cond = g_cond_new ();
2058 g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
2062 g_static_rw_lock_signal (GStaticRWLock* lock)
2064 if (lock->want_to_write && lock->write_cond)
2065 g_cond_signal (lock->write_cond);
2066 else if (lock->want_to_read && lock->read_cond)
2067 g_cond_broadcast (lock->read_cond);
2071 * g_static_rw_lock_reader_lock:
2072 * @lock: a #GStaticRWLock to lock for reading.
2074 * Locks @lock for reading. There may be unlimited concurrent locks for
2075 * reading of a #GStaticRWLock at the same time. If @lock is already
2076 * locked for writing by another thread or if another thread is already
2077 * waiting to lock @lock for writing, this function will block until
2078 * @lock is unlocked by the other writing thread and no other writing
2079 * threads want to lock @lock. This lock has to be unlocked by
2080 * g_static_rw_lock_reader_unlock().
2082 * #GStaticRWLock is not recursive. It might seem to be possible to
2083 * recursively lock for reading, but that can result in a deadlock, due
2084 * to writer preference.
2086 * Deprecated: 2.32: Use g_rw_lock_reader_lock() instead
2089 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
2091 g_return_if_fail (lock);
2093 if (!g_threads_got_initialized)
2096 g_static_mutex_lock (&lock->mutex);
2097 lock->want_to_read++;
2098 while (lock->have_writer || lock->want_to_write)
2099 g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
2100 lock->want_to_read--;
2101 lock->read_counter++;
2102 g_static_mutex_unlock (&lock->mutex);
2106 * g_static_rw_lock_reader_trylock:
2107 * @lock: a #GStaticRWLock to lock for reading.
2108 * @Returns: %TRUE, if @lock could be locked for reading.
2110 * Tries to lock @lock for reading. If @lock is already locked for
2111 * writing by another thread or if another thread is already waiting to
2112 * lock @lock for writing, immediately returns %FALSE. Otherwise locks
2113 * @lock for reading and returns %TRUE. This lock has to be unlocked by
2114 * g_static_rw_lock_reader_unlock().
2116 * Deprectated: 2.32: Use g_rw_lock_reader_trylock() instead
2119 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
2121 gboolean ret_val = FALSE;
2123 g_return_val_if_fail (lock, FALSE);
2125 if (!g_threads_got_initialized)
2128 g_static_mutex_lock (&lock->mutex);
2129 if (!lock->have_writer && !lock->want_to_write)
2131 lock->read_counter++;
2134 g_static_mutex_unlock (&lock->mutex);
2139 * g_static_rw_lock_reader_unlock:
2140 * @lock: a #GStaticRWLock to unlock after reading.
2142 * Unlocks @lock. If a thread waits to lock @lock for writing and all
2143 * locks for reading have been unlocked, the waiting thread is woken up
2144 * and can lock @lock for writing.
2146 * Deprectated: 2.32: Use g_rw_lock_reader_unlock() instead
2149 g_static_rw_lock_reader_unlock (GStaticRWLock* lock)
2151 g_return_if_fail (lock);
2153 if (!g_threads_got_initialized)
2156 g_static_mutex_lock (&lock->mutex);
2157 lock->read_counter--;
2158 if (lock->read_counter == 0)
2159 g_static_rw_lock_signal (lock);
2160 g_static_mutex_unlock (&lock->mutex);
2164 * g_static_rw_lock_writer_lock:
2165 * @lock: a #GStaticRWLock to lock for writing.
2167 * Locks @lock for writing. If @lock is already locked for writing or
2168 * reading by other threads, this function will block until @lock is
2169 * completely unlocked and then lock @lock for writing. While this
2170 * functions waits to lock @lock, no other thread can lock @lock for
2171 * reading. When @lock is locked for writing, no other thread can lock
2172 * @lock (neither for reading nor writing). This lock has to be
2173 * unlocked by g_static_rw_lock_writer_unlock().
2175 * Deprectated: 2.32: Use g_rw_lock_writer_lock() instead
2178 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
2180 g_return_if_fail (lock);
2182 if (!g_threads_got_initialized)
2185 g_static_mutex_lock (&lock->mutex);
2186 lock->want_to_write++;
2187 while (lock->have_writer || lock->read_counter)
2188 g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
2189 lock->want_to_write--;
2190 lock->have_writer = TRUE;
2191 g_static_mutex_unlock (&lock->mutex);
2195 * g_static_rw_lock_writer_trylock:
2196 * @lock: a #GStaticRWLock to lock for writing.
2197 * @Returns: %TRUE, if @lock could be locked for writing.
2199 * Tries to lock @lock for writing. If @lock is already locked (for
2200 * either reading or writing) by another thread, it immediately returns
2201 * %FALSE. Otherwise it locks @lock for writing and returns %TRUE. This
2202 * lock has to be unlocked by g_static_rw_lock_writer_unlock().
2204 * Deprectated: 2.32: Use g_rw_lock_writer_trylock() instead
2207 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
2209 gboolean ret_val = FALSE;
2211 g_return_val_if_fail (lock, FALSE);
2213 if (!g_threads_got_initialized)
2216 g_static_mutex_lock (&lock->mutex);
2217 if (!lock->have_writer && !lock->read_counter)
2219 lock->have_writer = TRUE;
2222 g_static_mutex_unlock (&lock->mutex);
2227 * g_static_rw_lock_writer_unlock:
2228 * @lock: a #GStaticRWLock to unlock after writing.
2230 * Unlocks @lock. If a thread is waiting to lock @lock for writing and
2231 * all locks for reading have been unlocked, the waiting thread is
2232 * woken up and can lock @lock for writing. If no thread is waiting to
2233 * lock @lock for writing, and some thread or threads are waiting to
2234 * lock @lock for reading, the waiting threads are woken up and can
2235 * lock @lock for reading.
2237 * Deprectated: 2.32: Use g_rw_lock_writer_unlock() instead
2240 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
2242 g_return_if_fail (lock);
2244 if (!g_threads_got_initialized)
2247 g_static_mutex_lock (&lock->mutex);
2248 lock->have_writer = FALSE;
2249 g_static_rw_lock_signal (lock);
2250 g_static_mutex_unlock (&lock->mutex);
2254 * g_static_rw_lock_free:
2255 * @lock: a #GStaticRWLock to be freed.
2257 * Releases all resources allocated to @lock.
2259 * You don't have to call this functions for a #GStaticRWLock with an
2260 * unbounded lifetime, i.e. objects declared 'static', but if you have
2261 * a #GStaticRWLock as a member of a structure, and the structure is
2262 * freed, you should also free the #GStaticRWLock.
2264 * Deprecated: 2.32: Use a #GRWLock instead
2267 g_static_rw_lock_free (GStaticRWLock* lock)
2269 g_return_if_fail (lock);
2271 if (lock->read_cond)
2273 g_cond_free (lock->read_cond);
2274 lock->read_cond = NULL;
2276 if (lock->write_cond)
2278 g_cond_free (lock->write_cond);
2279 lock->write_cond = NULL;
2281 g_static_mutex_free (&lock->mutex);
2284 /* Unsorted {{{1 ---------------------------------------------------------- */
2288 * @thread_func: function to call for all GThread structures
2289 * @user_data: second argument to @thread_func
2291 * Call @thread_func on all existing #GThread structures. Note that
2292 * threads may decide to exit while @thread_func is running, so
2293 * without intimate knowledge about the lifetime of foreign threads,
2294 * @thread_func shouldn't access the GThread* pointer passed in as
2295 * first argument. However, @thread_func will not be called for threads
2296 * which are known to have exited already.
2298 * Due to thread lifetime checks, this function has an execution complexity
2299 * which is quadratic in the number of existing threads.
2304 g_thread_foreach (GFunc thread_func,
2307 GSList *slist = NULL;
2308 GRealThread *thread;
2309 g_return_if_fail (thread_func != NULL);
2310 /* snapshot the list of threads for iteration */
2312 for (thread = g_thread_all_threads; thread; thread = thread->next)
2313 slist = g_slist_prepend (slist, thread);
2314 G_UNLOCK (g_thread);
2315 /* walk the list, skipping non-existent threads */
2318 GSList *node = slist;
2320 /* check whether the current thread still exists */
2322 for (thread = g_thread_all_threads; thread; thread = thread->next)
2323 if (thread == node->data)
2325 G_UNLOCK (g_thread);
2327 thread_func (thread, user_data);
2328 g_slist_free_1 (node);
2333 * g_thread_get_initialized:
2335 * Indicates if g_thread_init() has been called.
2337 * Returns: %TRUE if threads have been initialized.
2342 g_thread_get_initialized ()
2344 return g_thread_supported ();
2350 * Allocated and initializes a new #GMutex.
2352 * Returns: a newly allocated #GMutex. Use g_mutex_free() to free
2359 mutex = g_slice_new (GMutex);
2360 g_mutex_init (mutex);
2369 * Destroys a @mutex that has been created with g_mutex_new().
2371 * Calling g_mutex_free() on a locked mutex may result
2372 * in undefined behaviour.
2375 g_mutex_free (GMutex *mutex)
2377 g_mutex_clear (mutex);
2378 g_slice_free (GMutex, mutex);
2384 * Allocates and initializes a new #GCond.
2386 * Returns: a newly allocated #GCond. Free with g_cond_free()
2393 cond = g_slice_new (GCond);
2403 * Destroys a #GCond that has been created with g_cond_new().
2406 g_cond_free (GCond *cond)
2408 g_cond_clear (cond);
2409 g_slice_free (GCond, cond);
2414 * @destructor: a function to destroy the data keyed to
2415 * the #GPrivate when a thread ends
2417 * Creates a new #GPrivate. If @destructor is non-%NULL, it is a
2418 * pointer to a destructor function. Whenever a thread ends and the
2419 * corresponding pointer keyed to this instance of #GPrivate is
2420 * non-%NULL, the destructor is called with this pointer as the
2424 * #GStaticPrivate is a better choice for most uses.
2427 * <note><para>@destructor is used quite differently from @notify in
2428 * g_static_private_set().</para></note>
2430 * <note><para>A #GPrivate cannot be freed. Reuse it instead, if you
2431 * can, to avoid shortage, or use #GStaticPrivate.</para></note>
2433 * <note><para>This function will abort if g_thread_init() has not been
2434 * called yet.</para></note>
2436 * Returns: a newly allocated #GPrivate
2439 g_private_new (GDestroyNotify notify)
2443 key = g_slice_new (GPrivate);
2444 g_private_init (key, notify);
2449 GThreadFunctions g_thread_functions_for_glib_use =
2474 /* vim: set foldmethod=marker: */