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.
625 * If you use GLib from more than one thread, you must initialize the
626 * thread system by calling g_thread_init(). Most of the time you will
627 * only have to call <literal>g_thread_init (NULL)</literal>.
629 * <note><para>Do not call g_thread_init() with a non-%NULL parameter unless
630 * you really know what you are doing.</para></note>
632 * <note><para>g_thread_init() must not be called directly or indirectly as a
633 * callback from GLib. Also no mutexes may be currently locked while
634 * calling g_thread_init().</para></note>
636 * <note><para>g_thread_init() changes the way in which #GTimer measures
637 * elapsed time. As a consequence, timers that are running while
638 * g_thread_init() is called may report unreliable times.</para></note>
640 * Calling g_thread_init() multiple times is allowed (since version
641 * 2.24), but nothing happens except for the first call. If the
642 * argument is non-%NULL on such a call a warning will be printed, but
643 * otherwise the argument is ignored.
645 * If no thread system is available and @vtable is %NULL or if not all
646 * elements of @vtable are non-%NULL, then g_thread_init() will abort.
648 * <note><para>To use g_thread_init() in your program, you have to link with
649 * the libraries that the command <command>pkg-config --libs
650 * gthread-2.0</command> outputs. This is not the case for all the
651 * other thread related functions of GLib. Those can be used without
652 * having to link with the thread libraries.</para></note>
655 /* This must be called only once, before any threads are created.
656 * It will only be called from g_thread_init() in -lgthread.
659 g_thread_init_glib (void)
661 static gboolean already_done;
662 GRealThread* main_thread;
669 /* We let the main thread (the one that calls g_thread_init) inherit
670 * the static_private data set before calling g_thread_init
672 main_thread = (GRealThread*) g_thread_self ();
674 /* setup the basic threading system */
675 g_threads_got_initialized = TRUE;
676 g_private_init (&g_thread_specific_private, g_thread_cleanup);
677 g_private_set (&g_thread_specific_private, main_thread);
678 g_system_thread_self (&main_thread->system_thread);
680 /* accomplish log system initialization to enable messaging */
681 _g_messages_thread_init_nomessage ();
684 /* The following sections implement: GOnce, GStaticMutex, GStaticRecMutex,
688 /* GOnce {{{1 ------------------------------------------------------------- */
692 * @status: the status of the #GOnce
693 * @retval: the value returned by the call to the function, if @status
694 * is %G_ONCE_STATUS_READY
696 * A #GOnce struct controls a one-time initialization function. Any
697 * one-time initialization function must have its own unique #GOnce
706 * A #GOnce must be initialized with this macro before it can be used.
710 * GOnce my_once = G_ONCE_INIT;
719 * @G_ONCE_STATUS_NOTCALLED: the function has not been called yet.
720 * @G_ONCE_STATUS_PROGRESS: the function call is currently in progress.
721 * @G_ONCE_STATUS_READY: the function has been called.
723 * The possible statuses of a one-time initialization function
724 * controlled by a #GOnce struct.
731 * @once: a #GOnce structure
732 * @func: the #GThreadFunc function associated to @once. This function
733 * is called only once, regardless of the number of times it and
734 * its associated #GOnce struct are passed to g_once().
735 * @arg: data to be passed to @func
737 * The first call to this routine by a process with a given #GOnce
738 * struct calls @func with the given argument. Thereafter, subsequent
739 * calls to g_once() with the same #GOnce struct do not call @func
740 * again, but return the stored result of the first call. On return
741 * from g_once(), the status of @once will be %G_ONCE_STATUS_READY.
743 * For example, a mutex or a thread-specific data key must be created
744 * exactly once. In a threaded environment, calling g_once() ensures
745 * that the initialization is serialized across multiple threads.
747 * <note><para>Calling g_once() recursively on the same #GOnce struct in
748 * @func will lead to a deadlock.</para></note>
753 * get_debug_flags (void)
755 * static GOnce my_once = G_ONCE_INIT;
757 * g_once (&my_once, parse_debug_flags, NULL);
759 * return my_once.retval;
767 g_once_impl (GOnce *once,
771 g_mutex_lock (&g_once_mutex);
773 while (once->status == G_ONCE_STATUS_PROGRESS)
774 g_cond_wait (&g_once_cond, &g_once_mutex);
776 if (once->status != G_ONCE_STATUS_READY)
778 once->status = G_ONCE_STATUS_PROGRESS;
779 g_mutex_unlock (&g_once_mutex);
781 once->retval = func (arg);
783 g_mutex_lock (&g_once_mutex);
784 once->status = G_ONCE_STATUS_READY;
785 g_cond_broadcast (&g_once_cond);
788 g_mutex_unlock (&g_once_mutex);
795 * @value_location: location of a static initializable variable
797 * @Returns: %TRUE if the initialization section should be entered,
798 * %FALSE and blocks otherwise
800 * Function to be called when starting a critical initialization
801 * section. The argument @value_location must point to a static
802 * 0-initialized variable that will be set to a value other than 0 at
803 * the end of the initialization section. In combination with
804 * g_once_init_leave() and the unique address @value_location, it can
805 * be ensured that an initialization section will be executed only once
806 * during a program's life time, and that concurrent threads are
807 * blocked until initialization completed. To be used in constructs
812 * static gsize initialization_value = 0;
814 * if (g_once_init_enter (&initialization_value))
816 * gsize setup_value = 42; /<!-- -->* initialization code here *<!-- -->/
818 * g_once_init_leave (&initialization_value, setup_value);
821 * /<!-- -->* use initialization_value here *<!-- -->/
828 g_once_init_enter_impl (volatile gsize *value_location)
830 gboolean need_init = FALSE;
831 g_mutex_lock (&g_once_mutex);
832 if (g_atomic_pointer_get (value_location) == NULL)
834 if (!g_slist_find (g_once_init_list, (void*) value_location))
837 g_once_init_list = g_slist_prepend (g_once_init_list, (void*) value_location);
841 g_cond_wait (&g_once_cond, &g_once_mutex);
842 while (g_slist_find (g_once_init_list, (void*) value_location));
844 g_mutex_unlock (&g_once_mutex);
850 * @value_location: location of a static initializable variable
852 * @initialization_value: new non-0 value for *@value_location.
854 * Counterpart to g_once_init_enter(). Expects a location of a static
855 * 0-initialized initialization variable, and an initialization value
856 * other than 0. Sets the variable to the initialization value, and
857 * releases concurrent threads blocking in g_once_init_enter() on this
858 * initialization variable.
863 g_once_init_leave (volatile gsize *value_location,
864 gsize initialization_value)
866 g_return_if_fail (g_atomic_pointer_get (value_location) == NULL);
867 g_return_if_fail (initialization_value != 0);
868 g_return_if_fail (g_once_init_list != NULL);
870 g_atomic_pointer_set (value_location, initialization_value);
871 g_mutex_lock (&g_once_mutex);
872 g_once_init_list = g_slist_remove (g_once_init_list, (void*) value_location);
873 g_cond_broadcast (&g_once_cond);
874 g_mutex_unlock (&g_once_mutex);
877 /* GStaticMutex {{{1 ------------------------------------------------------ */
882 * A #GStaticMutex works like a #GMutex.
884 * Prior to GLib 2.32, GStaticMutex had the significant advantage
885 * that it doesn't need to be created at run-time, but can be defined
886 * at compile-time. Since 2.32, #GMutex can be statically allocated
887 * as well, and GStaticMutex has been deprecated.
889 * Here is a version of our give_me_next_number() example using
894 * Using <structname>GStaticMutex</structname>
895 * to simplify thread-safe programming
899 * give_me_next_number (void)
901 * static int current_number = 0;
903 * static GStaticMutex mutex = G_STATIC_MUTEX_INIT;
905 * g_static_mutex_lock (&mutex);
906 * ret_val = current_number = calc_next_number (current_number);
907 * g_static_mutex_unlock (&mutex);
914 * Sometimes you would like to dynamically create a mutex. If you don't
915 * want to require prior calling to g_thread_init(), because your code
916 * should also be usable in non-threaded programs, you are not able to
917 * use g_mutex_new() and thus #GMutex, as that requires a prior call to
918 * g_thread_init(). In theses cases you can also use a #GStaticMutex.
919 * It must be initialized with g_static_mutex_init() before using it
920 * and freed with with g_static_mutex_free() when not needed anymore to
921 * free up any allocated resources.
923 * Even though #GStaticMutex is not opaque, it should only be used with
924 * the following functions, as it is defined differently on different
927 * All of the <function>g_static_mutex_*</function> functions apart
928 * from <function>g_static_mutex_get_mutex</function> can also be used
929 * even if g_thread_init() has not yet been called. Then they do
930 * nothing, apart from <function>g_static_mutex_trylock</function>,
931 * which does nothing but returning %TRUE.
933 * <note><para>All of the <function>g_static_mutex_*</function>
934 * functions are actually macros. Apart from taking their addresses, you
935 * can however use them as if they were functions.</para></note>
939 * G_STATIC_MUTEX_INIT:
941 * A #GStaticMutex must be initialized with this macro, before it can
942 * be used. This macro can used be to initialize a variable, but it
943 * cannot be assigned to a variable. In that case you have to use
944 * g_static_mutex_init().
947 * GStaticMutex my_mutex = G_STATIC_MUTEX_INIT;
952 * g_static_mutex_init:
953 * @mutex: a #GStaticMutex to be initialized.
955 * Initializes @mutex.
956 * Alternatively you can initialize it with #G_STATIC_MUTEX_INIT.
958 * Deprecated: 2.32: Use g_mutex_init()
961 g_static_mutex_init (GStaticMutex *mutex)
963 static const GStaticMutex init_mutex = G_STATIC_MUTEX_INIT;
965 g_return_if_fail (mutex);
970 /* IMPLEMENTATION NOTE:
972 * On some platforms a GStaticMutex is actually a normal GMutex stored
973 * inside of a structure instead of being allocated dynamically. We can
974 * only do this for platforms on which we know, in advance, how to
975 * allocate (size) and initialise (value) that memory.
977 * On other platforms, a GStaticMutex is nothing more than a pointer to
978 * a GMutex. In that case, the first access we make to the static mutex
979 * must first allocate the normal GMutex and store it into the pointer.
981 * configure.ac writes macros into glibconfig.h to determine if
982 * g_static_mutex_get_mutex() accesses the structure in memory directly
983 * (on platforms where we are able to do that) or if it ends up here,
984 * where we may have to allocate the GMutex before returning it.
988 * g_static_mutex_get_mutex:
989 * @mutex: a #GStaticMutex.
990 * @Returns: the #GMutex corresponding to @mutex.
992 * For some operations (like g_cond_wait()) you must have a #GMutex
993 * instead of a #GStaticMutex. This function will return the
994 * corresponding #GMutex for @mutex.
996 * Deprecated: 2.32: Just use a #GMutex
999 g_static_mutex_get_mutex_impl (GMutex** mutex)
1003 if (!g_thread_supported ())
1006 result = g_atomic_pointer_get (mutex);
1010 g_mutex_lock (&g_once_mutex);
1015 result = g_mutex_new ();
1016 g_atomic_pointer_set (mutex, result);
1019 g_mutex_unlock (&g_once_mutex);
1025 /* IMPLEMENTATION NOTE:
1027 * g_static_mutex_lock(), g_static_mutex_trylock() and
1028 * g_static_mutex_unlock() are all preprocessor macros that wrap the
1029 * corresponding g_mutex_*() function around a call to
1030 * g_static_mutex_get_mutex().
1034 * g_static_mutex_lock:
1035 * @mutex: a #GStaticMutex.
1037 * Works like g_mutex_lock(), but for a #GStaticMutex.
1039 * Deprecated: 2.32: Use g_mutex_lock()
1043 * g_static_mutex_trylock:
1044 * @mutex: a #GStaticMutex.
1045 * @Returns: %TRUE, if the #GStaticMutex could be locked.
1047 * Works like g_mutex_trylock(), but for a #GStaticMutex.
1049 * Deprecated: 2.32: Use g_mutex_trylock()
1053 * g_static_mutex_unlock:
1054 * @mutex: a #GStaticMutex.
1056 * Works like g_mutex_unlock(), but for a #GStaticMutex.
1058 * Deprecated: 2.32: Use g_mutex_unlock()
1062 * g_static_mutex_free:
1063 * @mutex: a #GStaticMutex to be freed.
1065 * Releases all resources allocated to @mutex.
1067 * You don't have to call this functions for a #GStaticMutex with an
1068 * unbounded lifetime, i.e. objects declared 'static', but if you have
1069 * a #GStaticMutex as a member of a structure and the structure is
1070 * freed, you should also free the #GStaticMutex.
1072 * <note><para>Calling g_static_mutex_free() on a locked mutex may
1073 * result in undefined behaviour.</para></note>
1075 * Deprecated: 2.32: Use g_mutex_free()
1078 g_static_mutex_free (GStaticMutex* mutex)
1080 GMutex **runtime_mutex;
1082 g_return_if_fail (mutex);
1084 /* The runtime_mutex is the first (or only) member of GStaticMutex,
1085 * see both versions (of glibconfig.h) in configure.ac. Note, that
1086 * this variable is NULL, if g_thread_init() hasn't been called or
1087 * if we're using the default thread implementation and it provides
1088 * static mutexes. */
1089 runtime_mutex = ((GMutex**)mutex);
1092 g_mutex_free (*runtime_mutex);
1094 *runtime_mutex = NULL;
1097 /* ------------------------------------------------------------------------ */
1102 * A #GStaticRecMutex works like a #GStaticMutex, but it can be locked
1103 * multiple times by one thread. If you enter it n times, you have to
1104 * unlock it n times again to let other threads lock it. An exception
1105 * is the function g_static_rec_mutex_unlock_full(): that allows you to
1106 * unlock a #GStaticRecMutex completely returning the depth, (i.e. the
1107 * number of times this mutex was locked). The depth can later be used
1108 * to restore the state of the #GStaticRecMutex by calling
1109 * g_static_rec_mutex_lock_full(). In GLib 2.32, #GStaticRecMutex has
1110 * been deprecated in favor of #GRecMutex.
1112 * Even though #GStaticRecMutex is not opaque, it should only be used
1113 * with the following functions.
1115 * All of the <function>g_static_rec_mutex_*</function> functions can
1116 * be used even if g_thread_init() has not been called. Then they do
1117 * nothing, apart from <function>g_static_rec_mutex_trylock</function>,
1118 * which does nothing but returning %TRUE.
1122 * G_STATIC_REC_MUTEX_INIT:
1124 * A #GStaticRecMutex must be initialized with this macro before it can
1125 * be used. This macro can used be to initialize a variable, but it
1126 * cannot be assigned to a variable. In that case you have to use
1127 * g_static_rec_mutex_init().
1130 * GStaticRecMutex my_mutex = G_STATIC_REC_MUTEX_INIT;
1135 * g_static_rec_mutex_init:
1136 * @mutex: a #GStaticRecMutex to be initialized.
1138 * A #GStaticRecMutex must be initialized with this function before it
1139 * can be used. Alternatively you can initialize it with
1140 * #G_STATIC_REC_MUTEX_INIT.
1142 * Deprecated: 2.32: Use g_rec_mutex_init()
1145 g_static_rec_mutex_init (GStaticRecMutex *mutex)
1147 static const GStaticRecMutex init_mutex = G_STATIC_REC_MUTEX_INIT;
1149 g_return_if_fail (mutex);
1151 *mutex = init_mutex;
1155 * g_static_rec_mutex_lock:
1156 * @mutex: a #GStaticRecMutex to lock.
1158 * Locks @mutex. If @mutex is already locked by another thread, the
1159 * current thread will block until @mutex is unlocked by the other
1160 * thread. If @mutex is already locked by the calling thread, this
1161 * functions increases the depth of @mutex and returns immediately.
1163 * Deprecated: 2.32: Use g_rec_mutex_lock()
1166 g_static_rec_mutex_lock (GStaticRecMutex* mutex)
1170 g_return_if_fail (mutex);
1172 if (!g_thread_supported ())
1175 g_system_thread_self (&self);
1177 if (g_system_thread_equal (&self, &mutex->owner))
1182 g_static_mutex_lock (&mutex->mutex);
1183 g_system_thread_assign (mutex->owner, self);
1188 * g_static_rec_mutex_trylock:
1189 * @mutex: a #GStaticRecMutex to lock.
1190 * @Returns: %TRUE, if @mutex could be locked.
1192 * Tries to lock @mutex. If @mutex is already locked by another thread,
1193 * it immediately returns %FALSE. Otherwise it locks @mutex and returns
1194 * %TRUE. If @mutex is already locked by the calling thread, this
1195 * functions increases the depth of @mutex and immediately returns
1198 * Deprecated: 2.32: Use g_rec_mutex_trylock()
1201 g_static_rec_mutex_trylock (GStaticRecMutex* mutex)
1205 g_return_val_if_fail (mutex, FALSE);
1207 if (!g_thread_supported ())
1210 g_system_thread_self (&self);
1212 if (g_system_thread_equal (&self, &mutex->owner))
1218 if (!g_static_mutex_trylock (&mutex->mutex))
1221 g_system_thread_assign (mutex->owner, self);
1227 * g_static_rec_mutex_unlock:
1228 * @mutex: a #GStaticRecMutex to unlock.
1230 * Unlocks @mutex. Another thread will be allowed to lock @mutex only
1231 * when it has been unlocked as many times as it had been locked
1232 * before. If @mutex is completely unlocked and another thread is
1233 * blocked in a g_static_rec_mutex_lock() call for @mutex, it will be
1234 * woken and can lock @mutex itself.
1236 * Deprecated: 2.32: Use g_rec_mutex_unlock()
1239 g_static_rec_mutex_unlock (GStaticRecMutex* mutex)
1241 g_return_if_fail (mutex);
1243 if (!g_thread_supported ())
1246 if (mutex->depth > 1)
1251 g_system_thread_assign (mutex->owner, zero_thread);
1252 g_static_mutex_unlock (&mutex->mutex);
1256 * g_static_rec_mutex_lock_full:
1257 * @mutex: a #GStaticRecMutex to lock.
1258 * @depth: number of times this mutex has to be unlocked to be
1259 * completely unlocked.
1261 * Works like calling g_static_rec_mutex_lock() for @mutex @depth times.
1263 * Deprecated: 2.32: Use g_rec_mutex_lock()
1266 g_static_rec_mutex_lock_full (GStaticRecMutex *mutex,
1270 g_return_if_fail (mutex);
1272 if (!g_thread_supported ())
1278 g_system_thread_self (&self);
1280 if (g_system_thread_equal (&self, &mutex->owner))
1282 mutex->depth += depth;
1285 g_static_mutex_lock (&mutex->mutex);
1286 g_system_thread_assign (mutex->owner, self);
1287 mutex->depth = depth;
1291 * g_static_rec_mutex_unlock_full:
1292 * @mutex: a #GStaticRecMutex to completely unlock.
1293 * @Returns: number of times @mutex has been locked by the current
1296 * Completely unlocks @mutex. If another thread is blocked in a
1297 * g_static_rec_mutex_lock() call for @mutex, it will be woken and can
1298 * lock @mutex itself. This function returns the number of times that
1299 * @mutex has been locked by the current thread. To restore the state
1300 * before the call to g_static_rec_mutex_unlock_full() you can call
1301 * g_static_rec_mutex_lock_full() with the depth returned by this
1304 * Deprecated: 2.32: Use g_rec_mutex_unlock()
1307 g_static_rec_mutex_unlock_full (GStaticRecMutex *mutex)
1311 g_return_val_if_fail (mutex, 0);
1313 if (!g_thread_supported ())
1316 depth = mutex->depth;
1318 g_system_thread_assign (mutex->owner, zero_thread);
1320 g_static_mutex_unlock (&mutex->mutex);
1326 * g_static_rec_mutex_free:
1327 * @mutex: a #GStaticRecMutex to be freed.
1329 * Releases all resources allocated to a #GStaticRecMutex.
1331 * You don't have to call this functions for a #GStaticRecMutex with an
1332 * unbounded lifetime, i.e. objects declared 'static', but if you have
1333 * a #GStaticRecMutex as a member of a structure and the structure is
1334 * freed, you should also free the #GStaticRecMutex.
1336 * Deprecated: 2.32: Use g_rec_mutex_clear()
1339 g_static_rec_mutex_free (GStaticRecMutex *mutex)
1341 g_return_if_fail (mutex);
1343 g_static_mutex_free (&mutex->mutex);
1346 /* GStaticPrivate {{{1 ---------------------------------------------------- */
1351 * A #GStaticPrivate works almost like a #GPrivate, but it has one
1352 * significant advantage. It doesn't need to be created at run-time
1353 * like a #GPrivate, but can be defined at compile-time. This is
1354 * similar to the difference between #GMutex and #GStaticMutex. Now
1355 * look at our <function>give_me_next_number()</function> example with
1359 * <title>Using GStaticPrivate for per-thread data</title>
1362 * give_me_next_number (<!-- -->)
1364 * static GStaticPrivate current_number_key = G_STATIC_PRIVATE_INIT;
1365 * int *current_number = g_static_private_get (&current_number_key);
1367 * if (!current_number)
1369 * current_number = g_new (int,1);
1370 * *current_number = 0;
1371 * g_static_private_set (&current_number_key, current_number, g_free);
1374 * *current_number = calc_next_number (*current_number);
1376 * return *current_number;
1383 * G_STATIC_PRIVATE_INIT:
1385 * Every #GStaticPrivate must be initialized with this macro, before it
1389 * GStaticPrivate my_private = G_STATIC_PRIVATE_INIT;
1394 * g_static_private_init:
1395 * @private_key: a #GStaticPrivate to be initialized.
1397 * Initializes @private_key. Alternatively you can initialize it with
1398 * #G_STATIC_PRIVATE_INIT.
1401 g_static_private_init (GStaticPrivate *private_key)
1403 private_key->index = 0;
1407 * g_static_private_get:
1408 * @private_key: a #GStaticPrivate.
1409 * @Returns: the corresponding pointer.
1411 * Works like g_private_get() only for a #GStaticPrivate.
1413 * This function works even if g_thread_init() has not yet been called.
1416 g_static_private_get (GStaticPrivate *private_key)
1418 GRealThread *self = (GRealThread*) g_thread_self ();
1420 gpointer ret = NULL;
1422 LOCK_PRIVATE_DATA (self);
1424 array = self->private_data;
1426 if (array && private_key->index != 0 && private_key->index <= array->len)
1427 ret = g_array_index (array, GStaticPrivateNode,
1428 private_key->index - 1).data;
1430 UNLOCK_PRIVATE_DATA (self);
1435 * g_static_private_set:
1436 * @private_key: a #GStaticPrivate.
1437 * @data: the new pointer.
1438 * @notify: a function to be called with the pointer whenever the
1439 * current thread ends or sets this pointer again.
1441 * Sets the pointer keyed to @private_key for the current thread and
1442 * the function @notify to be called with that pointer (%NULL or
1443 * non-%NULL), whenever the pointer is set again or whenever the
1444 * current thread ends.
1446 * This function works even if g_thread_init() has not yet been called.
1447 * If g_thread_init() is called later, the @data keyed to @private_key
1448 * will be inherited only by the main thread, i.e. the one that called
1451 * <note><para>@notify is used quite differently from @destructor in
1452 * g_private_new().</para></note>
1455 g_static_private_set (GStaticPrivate *private_key,
1457 GDestroyNotify notify)
1459 GRealThread *self = (GRealThread*) g_thread_self ();
1461 static guint next_index = 0;
1462 GStaticPrivateNode *node;
1463 gpointer ddata = NULL;
1464 GDestroyNotify ddestroy = NULL;
1466 if (!private_key->index)
1470 if (!private_key->index)
1472 if (g_thread_free_indices)
1474 private_key->index =
1475 GPOINTER_TO_UINT (g_thread_free_indices->data);
1476 g_thread_free_indices =
1477 g_slist_delete_link (g_thread_free_indices,
1478 g_thread_free_indices);
1481 private_key->index = ++next_index;
1484 G_UNLOCK (g_thread);
1487 LOCK_PRIVATE_DATA (self);
1489 array = self->private_data;
1492 array = g_array_new (FALSE, TRUE, sizeof (GStaticPrivateNode));
1493 self->private_data = array;
1496 if (private_key->index > array->len)
1497 g_array_set_size (array, private_key->index);
1499 node = &g_array_index (array, GStaticPrivateNode, private_key->index - 1);
1502 ddestroy = node->destroy;
1505 node->destroy = notify;
1507 UNLOCK_PRIVATE_DATA (self);
1514 * g_static_private_free:
1515 * @private_key: a #GStaticPrivate to be freed.
1517 * Releases all resources allocated to @private_key.
1519 * You don't have to call this functions for a #GStaticPrivate with an
1520 * unbounded lifetime, i.e. objects declared 'static', but if you have
1521 * a #GStaticPrivate as a member of a structure and the structure is
1522 * freed, you should also free the #GStaticPrivate.
1525 g_static_private_free (GStaticPrivate *private_key)
1527 guint idx = private_key->index;
1528 GRealThread *thread, *next;
1529 GArray *garbage = NULL;
1534 private_key->index = 0;
1538 thread = g_thread_all_threads;
1540 for (thread = g_thread_all_threads; thread; thread = next)
1544 next = thread->next;
1546 LOCK_PRIVATE_DATA (thread);
1548 array = thread->private_data;
1550 if (array && idx <= array->len)
1552 GStaticPrivateNode *node = &g_array_index (array,
1555 gpointer ddata = node->data;
1556 GDestroyNotify ddestroy = node->destroy;
1559 node->destroy = NULL;
1563 /* defer non-trivial destruction til after we've finished
1564 * iterating, since we must continue to hold the lock */
1565 if (garbage == NULL)
1566 garbage = g_array_new (FALSE, TRUE,
1567 sizeof (GStaticPrivateNode));
1569 g_array_set_size (garbage, garbage->len + 1);
1571 node = &g_array_index (garbage, GStaticPrivateNode,
1574 node->destroy = ddestroy;
1578 UNLOCK_PRIVATE_DATA (thread);
1580 g_thread_free_indices = g_slist_prepend (g_thread_free_indices,
1581 GUINT_TO_POINTER (idx));
1582 G_UNLOCK (g_thread);
1588 for (i = 0; i < garbage->len; i++)
1590 GStaticPrivateNode *node;
1592 node = &g_array_index (garbage, GStaticPrivateNode, i);
1593 node->destroy (node->data);
1596 g_array_free (garbage, TRUE);
1600 /* GThread Extra Functions {{{1 ------------------------------------------- */
1602 g_thread_cleanup (gpointer data)
1606 GRealThread* thread = data;
1609 LOCK_PRIVATE_DATA (thread);
1610 array = thread->private_data;
1611 thread->private_data = NULL;
1612 UNLOCK_PRIVATE_DATA (thread);
1618 for (i = 0; i < array->len; i++ )
1620 GStaticPrivateNode *node =
1621 &g_array_index (array, GStaticPrivateNode, i);
1623 node->destroy (node->data);
1625 g_array_free (array, TRUE);
1628 /* We only free the thread structure, if it isn't joinable. If
1629 it is, the structure is freed in g_thread_join */
1630 if (!thread->thread.joinable)
1635 for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
1642 g_thread_all_threads = t->next;
1646 G_UNLOCK (g_thread);
1648 /* Just to make sure, this isn't used any more */
1649 g_system_thread_assign (thread->system_thread, zero_thread);
1655 #define G_NSEC_PER_SEC 1000000000
1660 return g_get_monotonic_time () * 1000;
1664 g_thread_create_proxy (gpointer data)
1666 GRealThread* thread = data;
1670 /* This has to happen before G_LOCK, as that might call g_thread_self */
1671 g_private_set (&g_thread_specific_private, data);
1673 /* the lock makes sure, that thread->system_thread is written,
1674 before thread->thread.func is called. See g_thread_create. */
1676 G_UNLOCK (g_thread);
1678 thread->retval = thread->thread.func (thread->thread.data);
1685 * @func: a function to execute in the new thread
1686 * @data: an argument to supply to the new thread
1687 * @joinable: should this thread be joinable?
1688 * @error: return location for error, or %NULL
1690 * This function creates a new thread.
1692 * If @joinable is %TRUE, you can wait for this threads termination
1693 * calling g_thread_join(). Otherwise the thread will just disappear
1694 * when it terminates.
1696 * The new thread executes the function @func with the argument @data.
1697 * If the thread was created successfully, it is returned.
1699 * @error can be %NULL to ignore errors, or non-%NULL to report errors.
1700 * The error is set, if and only if the function returns %NULL.
1702 * Returns: the new #GThread on success
1705 g_thread_create (GThreadFunc func,
1710 return g_thread_create_with_stack_size (func, data, joinable, 0, error);
1714 * g_thread_create_with_stack_size:
1715 * @func: a function to execute in the new thread.
1716 * @data: an argument to supply to the new thread.
1717 * @joinable: should this thread be joinable?
1718 * @stack_size: a stack size for the new thread.
1719 * @error: return location for error.
1720 * @Returns: the new #GThread on success.
1722 * This function creates a new thread. If the underlying thread
1723 * implementation supports it, the thread gets a stack size of
1724 * @stack_size or the default value for the current platform, if
1727 * If @joinable is %TRUE, you can wait for this threads termination
1728 * calling g_thread_join(). Otherwise the thread will just disappear
1729 * when it terminates.
1731 * The new thread executes the function @func with the argument @data.
1732 * If the thread was created successfully, it is returned.
1734 * @error can be %NULL to ignore errors, or non-%NULL to report errors.
1735 * The error is set, if and only if the function returns %NULL.
1738 * Only use g_thread_create_with_stack_size() if you really can't use
1739 * g_thread_create() instead. g_thread_create() does not take
1740 * @stack_size, as it should only be used in cases in which it is
1745 g_thread_create_with_stack_size (GThreadFunc func,
1751 GRealThread* result;
1752 GError *local_error = NULL;
1753 g_return_val_if_fail (func, NULL);
1755 result = g_new0 (GRealThread, 1);
1757 result->thread.joinable = joinable;
1758 result->thread.func = func;
1759 result->thread.data = data;
1760 result->private_data = NULL;
1762 g_system_thread_create (g_thread_create_proxy, result,
1763 stack_size, joinable,
1764 &result->system_thread, &local_error);
1767 result->next = g_thread_all_threads;
1768 g_thread_all_threads = result;
1770 G_UNLOCK (g_thread);
1774 g_propagate_error (error, local_error);
1779 return (GThread*) result;
1783 * g_thread_create_full:
1784 * @func: a function to execute in the new thread.
1785 * @data: an argument to supply to the new thread.
1786 * @stack_size: a stack size for the new thread.
1787 * @joinable: should this thread be joinable?
1789 * @priority: ignored
1790 * @error: return location for error.
1791 * @Returns: the new #GThread on success.
1793 * This function creates a new thread.
1795 * Deprecated:2.32: The @bound and @priority arguments are now ignored.
1796 * Use g_thread_create() or g_thread_create_with_stack_size() instead.
1799 g_thread_create_full (GThreadFunc func,
1804 GThreadPriority priority,
1807 return g_thread_create_with_stack_size (func, data, joinable, stack_size, error);
1812 * @retval: the return value of this thread.
1814 * Exits the current thread. If another thread is waiting for that
1815 * thread using g_thread_join() and the current thread is joinable, the
1816 * waiting thread will be woken up and get @retval as the return value
1817 * of g_thread_join(). If the current thread is not joinable, @retval
1818 * is ignored. Calling
1821 * g_thread_exit (retval);
1824 * is equivalent to returning @retval from the function @func, as given
1825 * to g_thread_create().
1827 * <note><para>Never call g_thread_exit() from within a thread of a
1828 * #GThreadPool, as that will mess up the bookkeeping and lead to funny
1829 * and unwanted results.</para></note>
1832 g_thread_exit (gpointer retval)
1834 GRealThread* real = (GRealThread*) g_thread_self ();
1835 real->retval = retval;
1837 g_system_thread_exit ();
1842 * @thread: a #GThread to be waited for.
1843 * @Returns: the return value of the thread.
1845 * Waits until @thread finishes, i.e. the function @func, as given to
1846 * g_thread_create(), returns or g_thread_exit() is called by @thread.
1847 * All resources of @thread including the #GThread struct are released.
1848 * @thread must have been created with @joinable=%TRUE in
1849 * g_thread_create(). The value returned by @func or given to
1850 * g_thread_exit() by @thread is returned by this function.
1853 g_thread_join (GThread* thread)
1855 GRealThread* real = (GRealThread*) thread;
1859 g_return_val_if_fail (thread, NULL);
1860 g_return_val_if_fail (thread->joinable, NULL);
1861 g_return_val_if_fail (!g_system_thread_equal (&real->system_thread, &zero_thread), NULL);
1863 g_system_thread_join (&real->system_thread);
1865 retval = real->retval;
1868 for (t = g_thread_all_threads, p = NULL; t; p = t, t = t->next)
1870 if (t == (GRealThread*) thread)
1875 g_thread_all_threads = t->next;
1879 G_UNLOCK (g_thread);
1881 /* Just to make sure, this isn't used any more */
1882 thread->joinable = 0;
1883 g_system_thread_assign (real->system_thread, zero_thread);
1885 /* the thread structure for non-joinable threads is freed upon
1886 thread end. We free the memory here. This will leave a loose end,
1887 if a joinable thread is not joined. */
1895 * g_thread_set_priority:
1896 * @thread: a #GThread.
1897 * @priority: ignored
1899 * This function does nothing.
1901 * Deprecated:2.32: Thread priorities no longer have any effect.
1904 g_thread_set_priority (GThread *thread,
1905 GThreadPriority priority)
1911 * @Returns: the current thread.
1913 * This functions returns the #GThread corresponding to the calling
1917 g_thread_self (void)
1919 GRealThread* thread = g_private_get (&g_thread_specific_private);
1923 /* If no thread data is available, provide and set one. This
1924 can happen for the main thread and for threads, that are not
1926 thread = g_new0 (GRealThread, 1);
1927 thread->thread.joinable = FALSE; /* This is a save guess */
1928 thread->thread.func = NULL;
1929 thread->thread.data = NULL;
1930 thread->private_data = NULL;
1932 g_system_thread_self (&thread->system_thread);
1934 g_private_set (&g_thread_specific_private, thread);
1937 thread->next = g_thread_all_threads;
1938 g_thread_all_threads = thread;
1939 G_UNLOCK (g_thread);
1942 return (GThread*)thread;
1945 /* GStaticRWLock {{{1 ----------------------------------------------------- */
1950 * The #GStaticRWLock struct represents a read-write lock. A read-write
1951 * lock can be used for protecting data that some portions of code only
1952 * read from, while others also write. In such situations it is
1953 * desirable that several readers can read at once, whereas of course
1954 * only one writer may write at a time. Take a look at the following
1958 * <title>An array with access functions</title>
1960 * GStaticRWLock rwlock = G_STATIC_RW_LOCK_INIT;
1964 * my_array_get (guint index)
1966 * gpointer retval = NULL;
1971 * g_static_rw_lock_reader_lock (&rwlock);
1972 * if (index < array->len)
1973 * retval = g_ptr_array_index (array, index);
1974 * g_static_rw_lock_reader_unlock (&rwlock);
1980 * my_array_set (guint index, gpointer data)
1982 * g_static_rw_lock_writer_lock (&rwlock);
1985 * array = g_ptr_array_new (<!-- -->);
1987 * if (index >= array->len)
1988 * g_ptr_array_set_size (array, index+1);
1989 * g_ptr_array_index (array, index) = data;
1991 * g_static_rw_lock_writer_unlock (&rwlock);
1996 * This example shows an array which can be accessed by many readers
1997 * (the <function>my_array_get()</function> function) simultaneously,
1998 * whereas the writers (the <function>my_array_set()</function>
1999 * function) will only be allowed once at a time and only if no readers
2000 * currently access the array. This is because of the potentially
2001 * dangerous resizing of the array. Using these functions is fully
2002 * multi-thread safe now.
2004 * Most of the time, writers should have precedence over readers. That
2005 * means, for this implementation, that as soon as a writer wants to
2006 * lock the data, no other reader is allowed to lock the data, whereas,
2007 * of course, the readers that already have locked the data are allowed
2008 * to finish their operation. As soon as the last reader unlocks the
2009 * data, the writer will lock it.
2011 * Even though #GStaticRWLock is not opaque, it should only be used
2012 * with the following functions.
2014 * All of the <function>g_static_rw_lock_*</function> functions can be
2015 * used even if g_thread_init() has not been called. Then they do
2016 * nothing, apart from <function>g_static_rw_lock_*_trylock</function>,
2017 * which does nothing but returning %TRUE.
2019 * <note><para>A read-write lock has a higher overhead than a mutex. For
2020 * example, both g_static_rw_lock_reader_lock() and
2021 * g_static_rw_lock_reader_unlock() have to lock and unlock a
2022 * #GStaticMutex, so it takes at least twice the time to lock and unlock
2023 * a #GStaticRWLock that it does to lock and unlock a #GStaticMutex. So
2024 * only data structures that are accessed by multiple readers, and which
2025 * keep the lock for a considerable time justify a #GStaticRWLock. The
2026 * above example most probably would fare better with a
2027 * #GStaticMutex.</para></note>
2029 * Deprecated: 2.32: Use a #GRWLock instead
2033 * G_STATIC_RW_LOCK_INIT:
2035 * A #GStaticRWLock must be initialized with this macro before it can
2036 * be used. This macro can used be to initialize a variable, but it
2037 * cannot be assigned to a variable. In that case you have to use
2038 * g_static_rw_lock_init().
2041 * GStaticRWLock my_lock = G_STATIC_RW_LOCK_INIT;
2046 * g_static_rw_lock_init:
2047 * @lock: a #GStaticRWLock to be initialized.
2049 * A #GStaticRWLock must be initialized with this function before it
2050 * can be used. Alternatively you can initialize it with
2051 * #G_STATIC_RW_LOCK_INIT.
2053 * Deprecated: 2.32: Use g_rw_lock_init() instead
2056 g_static_rw_lock_init (GStaticRWLock* lock)
2058 static const GStaticRWLock init_lock = G_STATIC_RW_LOCK_INIT;
2060 g_return_if_fail (lock);
2066 g_static_rw_lock_wait (GCond** cond, GStaticMutex* mutex)
2069 *cond = g_cond_new ();
2070 g_cond_wait (*cond, g_static_mutex_get_mutex (mutex));
2074 g_static_rw_lock_signal (GStaticRWLock* lock)
2076 if (lock->want_to_write && lock->write_cond)
2077 g_cond_signal (lock->write_cond);
2078 else if (lock->want_to_read && lock->read_cond)
2079 g_cond_broadcast (lock->read_cond);
2083 * g_static_rw_lock_reader_lock:
2084 * @lock: a #GStaticRWLock to lock for reading.
2086 * Locks @lock for reading. There may be unlimited concurrent locks for
2087 * reading of a #GStaticRWLock at the same time. If @lock is already
2088 * locked for writing by another thread or if another thread is already
2089 * waiting to lock @lock for writing, this function will block until
2090 * @lock is unlocked by the other writing thread and no other writing
2091 * threads want to lock @lock. This lock has to be unlocked by
2092 * g_static_rw_lock_reader_unlock().
2094 * #GStaticRWLock is not recursive. It might seem to be possible to
2095 * recursively lock for reading, but that can result in a deadlock, due
2096 * to writer preference.
2098 * Deprecated: 2.32: Use g_rw_lock_reader_lock() instead
2101 g_static_rw_lock_reader_lock (GStaticRWLock* lock)
2103 g_return_if_fail (lock);
2105 if (!g_threads_got_initialized)
2108 g_static_mutex_lock (&lock->mutex);
2109 lock->want_to_read++;
2110 while (lock->have_writer || lock->want_to_write)
2111 g_static_rw_lock_wait (&lock->read_cond, &lock->mutex);
2112 lock->want_to_read--;
2113 lock->read_counter++;
2114 g_static_mutex_unlock (&lock->mutex);
2118 * g_static_rw_lock_reader_trylock:
2119 * @lock: a #GStaticRWLock to lock for reading.
2120 * @Returns: %TRUE, if @lock could be locked for reading.
2122 * Tries to lock @lock for reading. If @lock is already locked for
2123 * writing by another thread or if another thread is already waiting to
2124 * lock @lock for writing, immediately returns %FALSE. Otherwise locks
2125 * @lock for reading and returns %TRUE. This lock has to be unlocked by
2126 * g_static_rw_lock_reader_unlock().
2128 * Deprectated: 2.32: Use g_rw_lock_reader_trylock() instead
2131 g_static_rw_lock_reader_trylock (GStaticRWLock* lock)
2133 gboolean ret_val = FALSE;
2135 g_return_val_if_fail (lock, FALSE);
2137 if (!g_threads_got_initialized)
2140 g_static_mutex_lock (&lock->mutex);
2141 if (!lock->have_writer && !lock->want_to_write)
2143 lock->read_counter++;
2146 g_static_mutex_unlock (&lock->mutex);
2151 * g_static_rw_lock_reader_unlock:
2152 * @lock: a #GStaticRWLock to unlock after reading.
2154 * Unlocks @lock. If a thread waits to lock @lock for writing and all
2155 * locks for reading have been unlocked, the waiting thread is woken up
2156 * and can lock @lock for writing.
2158 * Deprectated: 2.32: Use g_rw_lock_reader_unlock() instead
2161 g_static_rw_lock_reader_unlock (GStaticRWLock* lock)
2163 g_return_if_fail (lock);
2165 if (!g_threads_got_initialized)
2168 g_static_mutex_lock (&lock->mutex);
2169 lock->read_counter--;
2170 if (lock->read_counter == 0)
2171 g_static_rw_lock_signal (lock);
2172 g_static_mutex_unlock (&lock->mutex);
2176 * g_static_rw_lock_writer_lock:
2177 * @lock: a #GStaticRWLock to lock for writing.
2179 * Locks @lock for writing. If @lock is already locked for writing or
2180 * reading by other threads, this function will block until @lock is
2181 * completely unlocked and then lock @lock for writing. While this
2182 * functions waits to lock @lock, no other thread can lock @lock for
2183 * reading. When @lock is locked for writing, no other thread can lock
2184 * @lock (neither for reading nor writing). This lock has to be
2185 * unlocked by g_static_rw_lock_writer_unlock().
2187 * Deprectated: 2.32: Use g_rw_lock_writer_lock() instead
2190 g_static_rw_lock_writer_lock (GStaticRWLock* lock)
2192 g_return_if_fail (lock);
2194 if (!g_threads_got_initialized)
2197 g_static_mutex_lock (&lock->mutex);
2198 lock->want_to_write++;
2199 while (lock->have_writer || lock->read_counter)
2200 g_static_rw_lock_wait (&lock->write_cond, &lock->mutex);
2201 lock->want_to_write--;
2202 lock->have_writer = TRUE;
2203 g_static_mutex_unlock (&lock->mutex);
2207 * g_static_rw_lock_writer_trylock:
2208 * @lock: a #GStaticRWLock to lock for writing.
2209 * @Returns: %TRUE, if @lock could be locked for writing.
2211 * Tries to lock @lock for writing. If @lock is already locked (for
2212 * either reading or writing) by another thread, it immediately returns
2213 * %FALSE. Otherwise it locks @lock for writing and returns %TRUE. This
2214 * lock has to be unlocked by g_static_rw_lock_writer_unlock().
2216 * Deprectated: 2.32: Use g_rw_lock_writer_trylock() instead
2219 g_static_rw_lock_writer_trylock (GStaticRWLock* lock)
2221 gboolean ret_val = FALSE;
2223 g_return_val_if_fail (lock, FALSE);
2225 if (!g_threads_got_initialized)
2228 g_static_mutex_lock (&lock->mutex);
2229 if (!lock->have_writer && !lock->read_counter)
2231 lock->have_writer = TRUE;
2234 g_static_mutex_unlock (&lock->mutex);
2239 * g_static_rw_lock_writer_unlock:
2240 * @lock: a #GStaticRWLock to unlock after writing.
2242 * Unlocks @lock. If a thread is waiting to lock @lock for writing and
2243 * all locks for reading have been unlocked, the waiting thread is
2244 * woken up and can lock @lock for writing. If no thread is waiting to
2245 * lock @lock for writing, and some thread or threads are waiting to
2246 * lock @lock for reading, the waiting threads are woken up and can
2247 * lock @lock for reading.
2249 * Deprectated: 2.32: Use g_rw_lock_writer_unlock() instead
2252 g_static_rw_lock_writer_unlock (GStaticRWLock* lock)
2254 g_return_if_fail (lock);
2256 if (!g_threads_got_initialized)
2259 g_static_mutex_lock (&lock->mutex);
2260 lock->have_writer = FALSE;
2261 g_static_rw_lock_signal (lock);
2262 g_static_mutex_unlock (&lock->mutex);
2266 * g_static_rw_lock_free:
2267 * @lock: a #GStaticRWLock to be freed.
2269 * Releases all resources allocated to @lock.
2271 * You don't have to call this functions for a #GStaticRWLock with an
2272 * unbounded lifetime, i.e. objects declared 'static', but if you have
2273 * a #GStaticRWLock as a member of a structure, and the structure is
2274 * freed, you should also free the #GStaticRWLock.
2276 * Deprecated: 2.32: Use a #GRWLock instead
2279 g_static_rw_lock_free (GStaticRWLock* lock)
2281 g_return_if_fail (lock);
2283 if (lock->read_cond)
2285 g_cond_free (lock->read_cond);
2286 lock->read_cond = NULL;
2288 if (lock->write_cond)
2290 g_cond_free (lock->write_cond);
2291 lock->write_cond = NULL;
2293 g_static_mutex_free (&lock->mutex);
2296 /* Unsorted {{{1 ---------------------------------------------------------- */
2300 * @thread_func: function to call for all GThread structures
2301 * @user_data: second argument to @thread_func
2303 * Call @thread_func on all existing #GThread structures. Note that
2304 * threads may decide to exit while @thread_func is running, so
2305 * without intimate knowledge about the lifetime of foreign threads,
2306 * @thread_func shouldn't access the GThread* pointer passed in as
2307 * first argument. However, @thread_func will not be called for threads
2308 * which are known to have exited already.
2310 * Due to thread lifetime checks, this function has an execution complexity
2311 * which is quadratic in the number of existing threads.
2316 g_thread_foreach (GFunc thread_func,
2319 GSList *slist = NULL;
2320 GRealThread *thread;
2321 g_return_if_fail (thread_func != NULL);
2322 /* snapshot the list of threads for iteration */
2324 for (thread = g_thread_all_threads; thread; thread = thread->next)
2325 slist = g_slist_prepend (slist, thread);
2326 G_UNLOCK (g_thread);
2327 /* walk the list, skipping non-existent threads */
2330 GSList *node = slist;
2332 /* check whether the current thread still exists */
2334 for (thread = g_thread_all_threads; thread; thread = thread->next)
2335 if (thread == node->data)
2337 G_UNLOCK (g_thread);
2339 thread_func (thread, user_data);
2340 g_slist_free_1 (node);
2345 * g_thread_get_initialized:
2347 * Indicates if g_thread_init() has been called.
2349 * Returns: %TRUE if threads have been initialized.
2354 g_thread_get_initialized ()
2356 return g_thread_supported ();
2362 * Allocated and initializes a new #GMutex.
2364 * Returns: a newly allocated #GMutex. Use g_mutex_free() to free
2371 mutex = g_slice_new (GMutex);
2372 g_mutex_init (mutex);
2381 * Destroys a @mutex that has been created with g_mutex_new().
2383 * Calling g_mutex_free() on a locked mutex may result
2384 * in undefined behaviour.
2387 g_mutex_free (GMutex *mutex)
2389 g_mutex_clear (mutex);
2390 g_slice_free (GMutex, mutex);
2396 * Allocates and initializes a new #GCond.
2398 * Returns: a newly allocated #GCond. Free with g_cond_free()
2405 cond = g_slice_new (GCond);
2415 * Destroys a #GCond that has been created with g_cond_new().
2418 g_cond_free (GCond *cond)
2420 g_cond_clear (cond);
2421 g_slice_free (GCond, cond);
2426 * @destructor: a function to destroy the data keyed to
2427 * the #GPrivate when a thread ends
2429 * Creates a new #GPrivate. If @destructor is non-%NULL, it is a
2430 * pointer to a destructor function. Whenever a thread ends and the
2431 * corresponding pointer keyed to this instance of #GPrivate is
2432 * non-%NULL, the destructor is called with this pointer as the
2436 * #GStaticPrivate is a better choice for most uses.
2439 * <note><para>@destructor is used quite differently from @notify in
2440 * g_static_private_set().</para></note>
2442 * <note><para>A #GPrivate cannot be freed. Reuse it instead, if you
2443 * can, to avoid shortage, or use #GStaticPrivate.</para></note>
2445 * <note><para>This function will abort if g_thread_init() has not been
2446 * called yet.</para></note>
2448 * Returns: a newly allocated #GPrivate
2451 g_private_new (GDestroyNotify notify)
2455 key = g_slice_new (GPrivate);
2456 g_private_init (key, notify);
2461 GThreadFunctions g_thread_functions_for_glib_use =
2486 /* vim: set foldmethod=marker: */