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.
24 /* Prelude {{{1 ----------------------------------------------------------- */
27 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
28 * file for a list of people on the GLib Team. See the ChangeLog
29 * files for a list of changes. These files are distributed with
30 * GLib at ftp://ftp.gtk.org/pub/gtk/.
37 /* implement gthread.h's inline functions */
38 #define G_IMPLEMENT_INLINES 1
39 #define __G_THREAD_C__
44 #include "gthreadprivate.h"
57 #endif /* G_OS_WIN32 */
60 #include "gstrfuncs.h"
61 #include "gtestutils.h"
66 * @short_description: portable support for threads, mutexes, locks,
67 * conditions and thread private data
68 * @see_also: #GThreadPool, #GAsyncQueue
70 * Threads act almost like processes, but unlike processes all threads
71 * of one process share the same memory. This is good, as it provides
72 * easy communication between the involved threads via this shared
73 * memory, and it is bad, because strange things (so called
74 * "Heisenbugs") might happen if the program is not carefully designed.
75 * In particular, due to the concurrent nature of threads, no
76 * assumptions on the order of execution of code running in different
77 * threads can be made, unless order is explicitly forced by the
78 * programmer through synchronization primitives.
80 * The aim of the thread-related functions in GLib is to provide a
81 * portable means for writing multi-threaded software. There are
82 * primitives for mutexes to protect the access to portions of memory
83 * (#GMutex, #GRecMutex and #GRWLock). There is a facility to use
84 * individual bits for locks (g_bit_lock()). There are primitives
85 * for condition variables to allow synchronization of threads (#GCond).
86 * There are primitives for thread-private data - data that every
87 * thread has a private instance of (#GPrivate). There are facilities
88 * for one-time initialization (#GOnce, g_once_init_enter()). Finally,
89 * there are primitives to create and manage threads (#GThread).
91 * The GLib threading system used to be initialized with g_thread_init().
92 * This is no longer necessary. Since version 2.32, the GLib threading
93 * system is automatically initialized at the start of your program,
94 * and all thread-creation functions and synchronization primitives
95 * are available right away.
97 * Note that it is not safe to assume that your program has no threads
98 * even if you don't call g_thread_new() yourself. GLib and GIO can
99 * and will create threads for their own purposes in some cases, such
100 * as when using g_unix_signal_source_new() or when using GDBus.
102 * Originally, UNIX did not have threads, and therefore some traditional
103 * UNIX APIs are problematic in threaded programs. Some notable examples
107 * C library functions that return data in statically allocated
108 * buffers, such as strtok() or strerror(). For many of these,
109 * there are thread-safe variants with a _r suffix, or you can
110 * look at corresponding GLib APIs (like g_strsplit() or g_strerror()).
113 * setenv() and unsetenv() manipulate the process environment in
114 * a not thread-safe way, and may interfere with getenv() calls
115 * in other threads. Note that getenv() calls may be
116 * <quote>hidden</quote> behind other APIs. For example, GNU gettext()
117 * calls getenv() under the covers. In general, it is best to treat
118 * the environment as readonly. If you absolutely have to modify the
119 * environment, do it early in main(), when no other threads are around yet.
122 * setlocale() changes the locale for the entire process, affecting
123 * all threads. Temporary changes to the locale are often made to
124 * change the behavior of string scanning or formatting functions
125 * like scanf() or printf(). GLib offers a number of string APIs
126 * (like g_ascii_formatd() or g_ascii_strtod()) that can often be
127 * used as an alternative. Or you can use the uselocale() function
128 * to change the locale only for the current thread.
131 * fork() only takes the calling thread into the child's copy of the
132 * process image. If other threads were executing in critical
133 * sections they could have left mutexes locked which could easily
134 * cause deadlocks in the new child. For this reason, you should
135 * call exit() or exec() as soon as possible in the child and only
136 * make signal-safe library calls before that.
139 * daemon() uses fork() in a way contrary to what is described
140 * above. It should not be used with GLib programs.
144 * GLib itself is internally completely thread-safe (all global data is
145 * automatically locked), but individual data structure instances are
146 * not automatically locked for performance reasons. For example,
147 * you must coordinate accesses to the same #GHashTable from multiple
148 * threads. The two notable exceptions from this rule are #GMainLoop
149 * and #GAsyncQueue, which <emphasis>are</emphasis> thread-safe and
150 * need no further application-level locking to be accessed from
151 * multiple threads. Most refcounting functions such as g_object_ref()
152 * are also thread-safe.
155 /* G_LOCK Documentation {{{1 ---------------------------------------------- */
159 * @name: the name of the lock
161 * The <literal>G_LOCK_*</literal> macros provide a convenient interface to #GMutex.
162 * #G_LOCK_DEFINE defines a lock. It can appear in any place where
163 * variable definitions may appear in programs, i.e. in the first block
164 * of a function or outside of functions. The @name parameter will be
165 * mangled to get the name of the #GMutex. This means that you
166 * can use names of existing variables as the parameter - e.g. the name
167 * of the variable you intend to protect with the lock. Look at our
168 * <function>give_me_next_number()</function> example using the
169 * <literal>G_LOCK_*</literal> macros:
172 * <title>Using the <literal>G_LOCK_*</literal> convenience macros</title>
174 * G_LOCK_DEFINE (current_number);
177 * give_me_next_number (void)
179 * static int current_number = 0;
182 * G_LOCK (current_number);
183 * ret_val = current_number = calc_next_number (current_number);
184 * G_UNLOCK (current_number);
193 * G_LOCK_DEFINE_STATIC:
194 * @name: the name of the lock
196 * This works like #G_LOCK_DEFINE, but it creates a static object.
201 * @name: the name of the lock
203 * This declares a lock, that is defined with #G_LOCK_DEFINE in another
209 * @name: the name of the lock
211 * Works like g_mutex_lock(), but for a lock defined with
217 * @name: the name of the lock
218 * @Returns: %TRUE, if the lock could be locked.
220 * Works like g_mutex_trylock(), but for a lock defined with
226 * @name: the name of the lock
228 * Works like g_mutex_unlock(), but for a lock defined with
232 /* GMutex Documentation {{{1 ------------------------------------------ */
237 * The #GMutex struct is an opaque data structure to represent a mutex
238 * (mutual exclusion). It can be used to protect data against shared
239 * access. Take for example the following function:
242 * <title>A function which will not work in a threaded environment</title>
245 * give_me_next_number (void)
247 * static int current_number = 0;
249 * /<!-- -->* now do a very complicated calculation to calculate the new
250 * * number, this might for example be a random number generator
252 * current_number = calc_next_number (current_number);
254 * return current_number;
259 * It is easy to see that this won't work in a multi-threaded
260 * application. There current_number must be protected against shared
261 * access. A #GMutex can be used as a solution to this problem:
264 * <title>Using GMutex to protected a shared variable</title>
267 * give_me_next_number (void)
269 * static GMutex mutex;
270 * static int current_number = 0;
273 * g_mutex_lock (&mutex);
274 * ret_val = current_number = calc_next_number (current_number);
275 * g_mutex_unlock (&mutex);
282 * Notice that the #GMutex is not initialised to any particular value.
283 * Its placement in static storage ensures that it will be initialised
284 * to all-zeros, which is appropriate.
286 * If a #GMutex is placed in other contexts (eg: embedded in a struct)
287 * then it must be explicitly initialised using g_mutex_init().
289 * A #GMutex should only be accessed via <function>g_mutex_</function>
293 /* GRecMutex Documentation {{{1 -------------------------------------- */
298 * The GRecMutex struct is an opaque data structure to represent a
299 * recursive mutex. It is similar to a #GMutex with the difference
300 * that it is possible to lock a GRecMutex multiple times in the same
301 * thread without deadlock. When doing so, care has to be taken to
302 * unlock the recursive mutex as often as it has been locked.
304 * If a #GRecMutex is allocated in static storage then it can be used
305 * without initialisation. Otherwise, you should call
306 * g_rec_mutex_init() on it and g_rec_mutex_clear() when done.
308 * A GRecMutex should only be accessed with the
309 * <function>g_rec_mutex_</function> functions.
314 /* GRWLock Documentation {{{1 ---------------------------------------- */
319 * The GRWLock struct is an opaque data structure to represent a
320 * reader-writer lock. It is similar to a #GMutex in that it allows
321 * multiple threads to coordinate access to a shared resource.
323 * The difference to a mutex is that a reader-writer lock discriminates
324 * between read-only ('reader') and full ('writer') access. While only
325 * one thread at a time is allowed write access (by holding the 'writer'
326 * lock via g_rw_lock_writer_lock()), multiple threads can gain
327 * simultaneous read-only access (by holding the 'reader' lock via
328 * g_rw_lock_reader_lock()).
331 * <title>An array with access functions</title>
337 * my_array_get (guint index)
339 * gpointer retval = NULL;
344 * g_rw_lock_reader_lock (&lock);
345 * if (index < array->len)
346 * retval = g_ptr_array_index (array, index);
347 * g_rw_lock_reader_unlock (&lock);
353 * my_array_set (guint index, gpointer data)
355 * g_rw_lock_writer_lock (&lock);
358 * array = g_ptr_array_new (<!-- -->);
360 * if (index >= array->len)
361 * g_ptr_array_set_size (array, index+1);
362 * g_ptr_array_index (array, index) = data;
364 * g_rw_lock_writer_unlock (&lock);
368 * This example shows an array which can be accessed by many readers
369 * (the <function>my_array_get()</function> function) simultaneously,
370 * whereas the writers (the <function>my_array_set()</function>
371 * function) will only be allowed once at a time and only if no readers
372 * currently access the array. This is because of the potentially
373 * dangerous resizing of the array. Using these functions is fully
374 * multi-thread safe now.
378 * If a #GRWLock is allocated in static storage then it can be used
379 * without initialisation. Otherwise, you should call
380 * g_rw_lock_init() on it and g_rw_lock_clear() when done.
382 * A GRWLock should only be accessed with the
383 * <function>g_rw_lock_</function> functions.
388 /* GCond Documentation {{{1 ------------------------------------------ */
393 * The #GCond struct is an opaque data structure that represents a
394 * condition. Threads can block on a #GCond if they find a certain
395 * condition to be false. If other threads change the state of this
396 * condition they signal the #GCond, and that causes the waiting
397 * threads to be woken up.
399 * Consider the following example of a shared variable. One or more
400 * threads can wait for data to be published to the variable and when
401 * another thread publishes the data, it can signal one of the waiting
402 * threads to wake up to collect the data.
406 * Using GCond to block a thread until a condition is satisfied
409 * gpointer current_data = NULL;
414 * push_data (gpointer data)
416 * g_mutex_lock (&data_mutex);
417 * current_data = data;
418 * g_cond_signal (&data_cond);
419 * g_mutex_unlock (&data_mutex);
427 * g_mutex_lock (&data_mutex);
428 * while (!current_data)
429 * g_cond_wait (&data_cond, &data_mutex);
430 * data = current_data;
431 * current_data = NULL;
432 * g_mutex_unlock (&data_mutex);
439 * Whenever a thread calls pop_data() now, it will wait until
440 * current_data is non-%NULL, i.e. until some other thread
441 * has called push_data().
443 * The example shows that use of a condition variable must always be
444 * paired with a mutex. Without the use of a mutex, there would be a
445 * race between the check of <varname>current_data</varname> by the
446 * while loop in <function>pop_data</function> and waiting.
447 * Specifically, another thread could set <varname>pop_data</varname>
448 * after the check, and signal the cond (with nobody waiting on it)
449 * before the first thread goes to sleep. #GCond is specifically useful
450 * for its ability to release the mutex and go to sleep atomically.
452 * It is also important to use the g_cond_wait() and g_cond_wait_until()
453 * functions only inside a loop which checks for the condition to be
454 * true. See g_cond_wait() for an explanation of why the condition may
455 * not be true even after it returns.
457 * If a #GCond is allocated in static storage then it can be used
458 * without initialisation. Otherwise, you should call g_cond_init() on
459 * it and g_cond_clear() when done.
461 * A #GCond should only be accessed via the <function>g_cond_</function>
465 /* GThread Documentation {{{1 ---------------------------------------- */
470 * The #GThread struct represents a running thread. This struct
471 * is returned by g_thread_new() or g_thread_try_new(). You can
472 * obtain the #GThread struct representing the current thead by
473 * calling g_thread_self().
475 * GThread is refcounted, see g_thread_ref() and g_thread_unref().
476 * The thread represented by it holds a reference while it is running,
477 * and g_thread_join() consumes the reference that it is given, so
478 * it is normally not necessary to manage GThread references
481 * The structure is opaque -- none of its fields may be directly
487 * @data: data passed to the thread
489 * Specifies the type of the @func functions passed to g_thread_new()
490 * or g_thread_try_new().
492 * Returns: the return value of the thread
496 * g_thread_supported:
498 * This macro returns %TRUE if the thread system is initialized,
499 * and %FALSE if it is not.
501 * For language bindings, g_thread_get_initialized() provides
502 * the same functionality as a function.
504 * Returns: %TRUE, if the thread system is initialized
507 /* GThreadError {{{1 ------------------------------------------------------- */
510 * @G_THREAD_ERROR_AGAIN: a thread couldn't be created due to resource
511 * shortage. Try again later.
513 * Possible errors of thread related functions.
519 * The error domain of the GLib thread subsystem.
521 G_DEFINE_QUARK ("g_thread_error", g_thread_error
)
523 /* Local Data {{{1 -------------------------------------------------------- */
525 static GMutex g_once_mutex
;
526 static GCond g_once_cond
;
527 static GSList
*g_once_init_list
= NULL
;
529 static void g_thread_cleanup (gpointer data
);
530 static GPrivate g_thread_specific_private
= G_PRIVATE_INIT (g_thread_cleanup
);
532 G_LOCK_DEFINE_STATIC (g_thread_new
);
534 /* GOnce {{{1 ------------------------------------------------------------- */
538 * @status: the status of the #GOnce
539 * @retval: the value returned by the call to the function, if @status
540 * is %G_ONCE_STATUS_READY
542 * A #GOnce struct controls a one-time initialization function. Any
543 * one-time initialization function must have its own unique #GOnce
552 * A #GOnce must be initialized with this macro before it can be used.
555 * GOnce my_once = G_ONCE_INIT;
563 * @G_ONCE_STATUS_NOTCALLED: the function has not been called yet.
564 * @G_ONCE_STATUS_PROGRESS: the function call is currently in progress.
565 * @G_ONCE_STATUS_READY: the function has been called.
567 * The possible statuses of a one-time initialization function
568 * controlled by a #GOnce struct.
575 * @once: a #GOnce structure
576 * @func: the #GThreadFunc function associated to @once. This function
577 * is called only once, regardless of the number of times it and
578 * its associated #GOnce struct are passed to g_once().
579 * @arg: data to be passed to @func
581 * The first call to this routine by a process with a given #GOnce
582 * struct calls @func with the given argument. Thereafter, subsequent
583 * calls to g_once() with the same #GOnce struct do not call @func
584 * again, but return the stored result of the first call. On return
585 * from g_once(), the status of @once will be %G_ONCE_STATUS_READY.
587 * For example, a mutex or a thread-specific data key must be created
588 * exactly once. In a threaded environment, calling g_once() ensures
589 * that the initialization is serialized across multiple threads.
591 * Calling g_once() recursively on the same #GOnce struct in
592 * @func will lead to a deadlock.
596 * get_debug_flags (void)
598 * static GOnce my_once = G_ONCE_INIT;
600 * g_once (&my_once, parse_debug_flags, NULL);
602 * return my_once.retval;
609 g_once_impl (GOnce
*once
,
613 g_mutex_lock (&g_once_mutex
);
615 while (once
->status
== G_ONCE_STATUS_PROGRESS
)
616 g_cond_wait (&g_once_cond
, &g_once_mutex
);
618 if (once
->status
!= G_ONCE_STATUS_READY
)
620 once
->status
= G_ONCE_STATUS_PROGRESS
;
621 g_mutex_unlock (&g_once_mutex
);
623 once
->retval
= func (arg
);
625 g_mutex_lock (&g_once_mutex
);
626 once
->status
= G_ONCE_STATUS_READY
;
627 g_cond_broadcast (&g_once_cond
);
630 g_mutex_unlock (&g_once_mutex
);
637 * @location: location of a static initializable variable containing 0
639 * Function to be called when starting a critical initialization
640 * section. The argument @location must point to a static
641 * 0-initialized variable that will be set to a value other than 0 at
642 * the end of the initialization section. In combination with
643 * g_once_init_leave() and the unique address @value_location, it can
644 * be ensured that an initialization section will be executed only once
645 * during a program's life time, and that concurrent threads are
646 * blocked until initialization completed. To be used in constructs
650 * static gsize initialization_value = 0;
652 * if (g_once_init_enter (&initialization_value))
654 * gsize setup_value = 42; /** initialization code here **/
656 * g_once_init_leave (&initialization_value, setup_value);
659 * /** use initialization_value here **/
662 * Returns: %TRUE if the initialization section should be entered,
663 * %FALSE and blocks otherwise
668 (g_once_init_enter
) (volatile void *location
)
670 volatile gsize
*value_location
= location
;
671 gboolean need_init
= FALSE
;
672 g_mutex_lock (&g_once_mutex
);
673 if (g_atomic_pointer_get (value_location
) == NULL
)
675 if (!g_slist_find (g_once_init_list
, (void*) value_location
))
678 g_once_init_list
= g_slist_prepend (g_once_init_list
, (void*) value_location
);
682 g_cond_wait (&g_once_cond
, &g_once_mutex
);
683 while (g_slist_find (g_once_init_list
, (void*) value_location
));
685 g_mutex_unlock (&g_once_mutex
);
691 * @location: location of a static initializable variable containing 0
692 * @result: new non-0 value for *@value_location
694 * Counterpart to g_once_init_enter(). Expects a location of a static
695 * 0-initialized initialization variable, and an initialization value
696 * other than 0. Sets the variable to the initialization value, and
697 * releases concurrent threads blocking in g_once_init_enter() on this
698 * initialization variable.
703 (g_once_init_leave
) (volatile void *location
,
706 volatile gsize
*value_location
= location
;
708 g_return_if_fail (g_atomic_pointer_get (value_location
) == NULL
);
709 g_return_if_fail (result
!= 0);
710 g_return_if_fail (g_once_init_list
!= NULL
);
712 g_atomic_pointer_set (value_location
, result
);
713 g_mutex_lock (&g_once_mutex
);
714 g_once_init_list
= g_slist_remove (g_once_init_list
, (void*) value_location
);
715 g_cond_broadcast (&g_once_cond
);
716 g_mutex_unlock (&g_once_mutex
);
719 /* GThread {{{1 -------------------------------------------------------- */
723 * @thread: a #GThread
725 * Increase the reference count on @thread.
727 * Returns: a new reference to @thread
732 g_thread_ref (GThread
*thread
)
734 GRealThread
*real
= (GRealThread
*) thread
;
736 g_atomic_int_inc (&real
->ref_count
);
743 * @thread: a #GThread
745 * Decrease the reference count on @thread, possibly freeing all
746 * resources associated with it.
748 * Note that each thread holds a reference to its #GThread while
749 * it is running, so it is safe to drop your own reference to it
750 * if you don't need it anymore.
755 g_thread_unref (GThread
*thread
)
757 GRealThread
*real
= (GRealThread
*) thread
;
759 if (g_atomic_int_dec_and_test (&real
->ref_count
))
762 g_system_thread_free (real
);
764 g_slice_free (GRealThread
, real
);
769 g_thread_cleanup (gpointer data
)
771 g_thread_unref (data
);
775 g_thread_proxy (gpointer data
)
777 GRealThread
* thread
= data
;
781 /* This has to happen before G_LOCK, as that might call g_thread_self */
782 g_private_set (&g_thread_specific_private
, data
);
784 /* The lock makes sure that g_thread_new_internal() has a chance to
785 * setup 'func' and 'data' before we make the call.
787 G_LOCK (g_thread_new
);
788 G_UNLOCK (g_thread_new
);
792 g_system_thread_set_name (thread
->name
);
793 g_free (thread
->name
);
797 thread
->retval
= thread
->thread
.func (thread
->thread
.data
);
804 * @name: a name for the new thread
805 * @func: a function to execute in the new thread
806 * @data: an argument to supply to the new thread
808 * This function creates a new thread. The new thread starts by invoking
809 * @func with the argument data. The thread will run until @func returns
810 * or until g_thread_exit() is called from the new thread. The return value
811 * of @func becomes the return value of the thread, which can be obtained
812 * with g_thread_join().
814 * The @name can be useful for discriminating threads in a debugger.
815 * Some systems restrict the length of @name to 16 bytes.
817 * If the thread can not be created the program aborts. See
818 * g_thread_try_new() if you want to attempt to deal with failures.
820 * To free the struct returned by this function, use g_thread_unref().
821 * Note that g_thread_join() implicitly unrefs the #GThread as well.
823 * Returns: the new #GThread
828 g_thread_new (const gchar
*name
,
832 GError
*error
= NULL
;
835 thread
= g_thread_new_internal (name
, g_thread_proxy
, func
, data
, 0, &error
);
837 if G_UNLIKELY (thread
== NULL
)
838 g_error ("creating thread '%s': %s", name
? name
: "", error
->message
);
845 * @name: a name for the new thread
846 * @func: a function to execute in the new thread
847 * @data: an argument to supply to the new thread
848 * @error: return location for error, or %NULL
850 * This function is the same as g_thread_new() except that
851 * it allows for the possibility of failure.
853 * If a thread can not be created (due to resource limits),
854 * @error is set and %NULL is returned.
856 * Returns: the new #GThread, or %NULL if an error occurred
861 g_thread_try_new (const gchar
*name
,
866 return g_thread_new_internal (name
, g_thread_proxy
, func
, data
, 0, error
);
870 g_thread_new_internal (const gchar
*name
,
879 g_return_val_if_fail (func
!= NULL
, NULL
);
881 G_LOCK (g_thread_new
);
882 thread
= g_system_thread_new (proxy
, stack_size
, error
);
885 thread
->ref_count
= 2;
887 thread
->thread
.joinable
= TRUE
;
888 thread
->thread
.func
= func
;
889 thread
->thread
.data
= data
;
890 thread
->name
= g_strdup (name
);
892 G_UNLOCK (g_thread_new
);
894 return (GThread
*) thread
;
899 * @retval: the return value of this thread
901 * Terminates the current thread.
903 * If another thread is waiting for us using g_thread_join() then the
904 * waiting thread will be woken up and get @retval as the return value
905 * of g_thread_join().
907 * Calling <literal>g_thread_exit (retval)</literal> is equivalent to
908 * returning @retval from the function @func, as given to g_thread_new().
911 * You must only call g_thread_exit() from a thread that you created
912 * yourself with g_thread_new() or related APIs. You must not call
913 * this function from a thread created with another threading library
914 * or or from within a #GThreadPool.
918 g_thread_exit (gpointer retval
)
920 GRealThread
* real
= (GRealThread
*) g_thread_self ();
922 if G_UNLIKELY (!real
->ours
)
923 g_error ("attempt to g_thread_exit() a thread not created by GLib");
925 real
->retval
= retval
;
927 g_system_thread_exit ();
932 * @thread: a #GThread
934 * Waits until @thread finishes, i.e. the function @func, as
935 * given to g_thread_new(), returns or g_thread_exit() is called.
936 * If @thread has already terminated, then g_thread_join()
937 * returns immediately.
939 * Any thread can wait for any other thread by calling g_thread_join(),
940 * not just its 'creator'. Calling g_thread_join() from multiple threads
941 * for the same @thread leads to undefined behaviour.
943 * The value returned by @func or given to g_thread_exit() is
944 * returned by this function.
946 * g_thread_join() consumes the reference to the passed-in @thread.
947 * This will usually cause the #GThread struct and associated resources
948 * to be freed. Use g_thread_ref() to obtain an extra reference if you
949 * want to keep the GThread alive beyond the g_thread_join() call.
951 * Returns: the return value of the thread
954 g_thread_join (GThread
*thread
)
956 GRealThread
*real
= (GRealThread
*) thread
;
959 g_return_val_if_fail (thread
, NULL
);
960 g_return_val_if_fail (real
->ours
, NULL
);
962 g_system_thread_wait (real
);
964 retval
= real
->retval
;
966 /* Just to make sure, this isn't used any more */
967 thread
->joinable
= 0;
969 g_thread_unref (thread
);
977 * This functions returns the #GThread corresponding to the
978 * current thread. Note that this function does not increase
979 * the reference count of the returned struct.
981 * This function will return a #GThread even for threads that
982 * were not created by GLib (i.e. those created by other threading
983 * APIs). This may be useful for thread identification purposes
984 * (i.e. comparisons) but you must not use GLib functions (such
985 * as g_thread_join()) on these threads.
987 * Returns: the #GThread representing the current thread
992 GRealThread
* thread
= g_private_get (&g_thread_specific_private
);
996 /* If no thread data is available, provide and set one.
997 * This can happen for the main thread and for threads
998 * that are not created by GLib.
1000 thread
= g_slice_new0 (GRealThread
);
1001 thread
->ref_count
= 1;
1003 g_private_set (&g_thread_specific_private
, thread
);
1006 return (GThread
*) thread
;
1010 /* vim: set foldmethod=marker: */