1 /*****************************************************************************
2 * pthread.c : pthread back-end for LibVLC
3 *****************************************************************************
4 * Copyright (C) 1999-2009 the VideoLAN team
6 * Authors: Jean-Marc Dressler <polux@via.ecp.fr>
7 * Samuel Hocevar <sam@zoy.org>
8 * Gildas Bazin <gbazin@netcourrier.com>
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
25 *****************************************************************************/
31 #include <vlc_common.h>
36 #include <unistd.h> /* fsync() */
42 # include <sys/syscall.h> /* SYS_gettid */
45 #ifdef HAVE_EXECINFO_H
46 # include <execinfo.h>
50 # include <sys/time.h> /* gettimeofday in vlc_cond_timedwait */
54 * Print a backtrace to the standard error for debugging purpose.
56 void vlc_trace (const char *fn, const char *file, unsigned line)
58 fprintf (stderr, "at %s:%u in %s\n", file, line, fn);
59 fflush (stderr); /* needed before switch to low-level I/O */
62 int len = backtrace (stack, sizeof (stack) / sizeof (stack[0]));
63 backtrace_symbols_fd (stack, len, 2);
68 static inline unsigned long vlc_threadid (void)
70 #if defined (__linux__)
71 /* glibc does not provide a call for this */
72 return syscall (SYS_gettid);
75 union { pthread_t th; unsigned long int i; } v = { };
76 v.th = pthread_self ();
83 /*****************************************************************************
84 * vlc_thread_fatal: Report an error from the threading layer
85 *****************************************************************************
86 * This is mostly meant for debugging.
87 *****************************************************************************/
89 vlc_thread_fatal (const char *action, int error,
90 const char *function, const char *file, unsigned line)
92 int canc = vlc_savecancel ();
93 fprintf (stderr, "LibVLC fatal error %s (%d) in thread %lu ",
94 action, error, vlc_threadid ());
95 vlc_trace (function, file, line);
97 /* Sometimes strerror_r() crashes too, so make sure we print an error
98 * message before we invoke it */
100 /* Avoid the strerror_r() prototype brain damage in glibc */
102 fprintf (stderr, " Error message: %m\n");
107 switch (strerror_r (error, buf, sizeof (buf)))
112 case ERANGE: /* should never happen */
113 msg = "unknwon (too big to display)";
116 msg = "unknown (invalid error number)";
119 fprintf (stderr, " Error message: %s\n", msg);
123 vlc_restorecancel (canc);
127 # define VLC_THREAD_ASSERT( action ) \
129 vlc_thread_fatal (action, val, __func__, __FILE__, __LINE__)
131 # define VLC_THREAD_ASSERT( action ) ((void)val)
134 #if defined (__GLIBC__) && (__GLIBC_MINOR__ < 6)
135 /* This is not prototyped under glibc, though it exists. */
136 int pthread_mutexattr_setkind_np( pthread_mutexattr_t *attr, int kind );
139 /*****************************************************************************
140 * vlc_mutex_init: initialize a mutex
141 *****************************************************************************/
142 void vlc_mutex_init( vlc_mutex_t *p_mutex )
144 pthread_mutexattr_t attr;
146 if( pthread_mutexattr_init( &attr ) )
149 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_NORMAL );
151 /* Create error-checking mutex to detect problems more easily. */
152 # if defined (__GLIBC__) && (__GLIBC__ == 2) && (__GLIBC_MINOR__ < 6)
153 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_ERRORCHECK_NP );
155 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_ERRORCHECK );
158 if( pthread_mutex_init( p_mutex, &attr ) )
160 pthread_mutexattr_destroy( &attr );
163 /*****************************************************************************
164 * vlc_mutex_init: initialize a recursive mutex (Do not use)
165 *****************************************************************************/
166 void vlc_mutex_init_recursive( vlc_mutex_t *p_mutex )
168 pthread_mutexattr_t attr;
170 pthread_mutexattr_init( &attr );
171 #if defined (__GLIBC__) && (__GLIBC__ == 2) && (__GLIBC_MINOR__ < 6)
172 pthread_mutexattr_setkind_np( &attr, PTHREAD_MUTEX_RECURSIVE_NP );
174 pthread_mutexattr_settype( &attr, PTHREAD_MUTEX_RECURSIVE );
176 if( pthread_mutex_init( p_mutex, &attr ) )
178 pthread_mutexattr_destroy( &attr );
183 * Destroys a mutex. The mutex must not be locked.
185 * @param p_mutex mutex to destroy
186 * @return always succeeds
188 void vlc_mutex_destroy (vlc_mutex_t *p_mutex)
190 int val = pthread_mutex_destroy( p_mutex );
191 VLC_THREAD_ASSERT ("destroying mutex");
195 # ifdef HAVE_VALGRIND_VALGRIND_H
196 # include <valgrind/valgrind.h>
198 # define RUNNING_ON_VALGRIND (0)
201 void vlc_assert_locked (vlc_mutex_t *p_mutex)
203 if (RUNNING_ON_VALGRIND > 0)
205 assert (pthread_mutex_lock (p_mutex) == EDEADLK);
210 * Acquires a mutex. If needed, waits for any other thread to release it.
211 * Beware of deadlocks when locking multiple mutexes at the same time,
212 * or when using mutexes from callbacks.
213 * This function is not a cancellation-point.
215 * @param p_mutex mutex initialized with vlc_mutex_init() or
216 * vlc_mutex_init_recursive()
218 void vlc_mutex_lock (vlc_mutex_t *p_mutex)
220 int val = pthread_mutex_lock( p_mutex );
221 VLC_THREAD_ASSERT ("locking mutex");
225 * Acquires a mutex if and only if it is not currently held by another thread.
226 * This function never sleeps and can be used in delay-critical code paths.
227 * This function is not a cancellation-point.
229 * <b>Beware</b>: If this function fails, then the mutex is held... by another
230 * thread. The calling thread must deal with the error appropriately. That
231 * typically implies postponing the operations that would have required the
232 * mutex. If the thread cannot defer those operations, then it must use
233 * vlc_mutex_lock(). If in doubt, use vlc_mutex_lock() instead.
235 * @param p_mutex mutex initialized with vlc_mutex_init() or
236 * vlc_mutex_init_recursive()
237 * @return 0 if the mutex could be acquired, an error code otherwise.
239 int vlc_mutex_trylock (vlc_mutex_t *p_mutex)
241 int val = pthread_mutex_trylock( p_mutex );
244 VLC_THREAD_ASSERT ("locking mutex");
249 * Releases a mutex (or crashes if the mutex is not locked by the caller).
250 * @param p_mutex mutex locked with vlc_mutex_lock().
252 void vlc_mutex_unlock (vlc_mutex_t *p_mutex)
254 int val = pthread_mutex_unlock( p_mutex );
255 VLC_THREAD_ASSERT ("unlocking mutex");
258 /*****************************************************************************
259 * vlc_cond_init: initialize a condition variable
260 *****************************************************************************/
261 void vlc_cond_init( vlc_cond_t *p_condvar )
263 pthread_condattr_t attr;
265 if (pthread_condattr_init (&attr))
267 #if !defined (_POSIX_CLOCK_SELECTION)
268 /* Fairly outdated POSIX support (that was defined in 2001) */
269 # define _POSIX_CLOCK_SELECTION (-1)
271 #if (_POSIX_CLOCK_SELECTION >= 0)
272 /* NOTE: This must be the same clock as the one in mtime.c */
273 pthread_condattr_setclock (&attr, CLOCK_MONOTONIC);
276 if (pthread_cond_init (p_condvar, &attr))
278 pthread_condattr_destroy (&attr);
282 * Destroys a condition variable. No threads shall be waiting or signaling the
284 * @param p_condvar condition variable to destroy
286 void vlc_cond_destroy (vlc_cond_t *p_condvar)
288 int val = pthread_cond_destroy( p_condvar );
289 VLC_THREAD_ASSERT ("destroying condition");
293 * Wakes up one thread waiting on a condition variable, if any.
294 * @param p_condvar condition variable
296 void vlc_cond_signal (vlc_cond_t *p_condvar)
298 int val = pthread_cond_signal( p_condvar );
299 VLC_THREAD_ASSERT ("signaling condition variable");
303 * Wakes up all threads (if any) waiting on a condition variable.
304 * @param p_cond condition variable
306 void vlc_cond_broadcast (vlc_cond_t *p_condvar)
308 pthread_cond_broadcast (p_condvar);
312 * Waits for a condition variable. The calling thread will be suspended until
313 * another thread calls vlc_cond_signal() or vlc_cond_broadcast() on the same
314 * condition variable, the thread is cancelled with vlc_cancel(), or the
315 * system causes a "spurious" unsolicited wake-up.
317 * A mutex is needed to wait on a condition variable. It must <b>not</b> be
318 * a recursive mutex. Although it is possible to use the same mutex for
319 * multiple condition, it is not valid to use different mutexes for the same
320 * condition variable at the same time from different threads.
322 * In case of thread cancellation, the mutex is always locked before
323 * cancellation proceeds.
325 * The canonical way to use a condition variable to wait for event foobar is:
327 vlc_mutex_lock (&lock);
328 mutex_cleanup_push (&lock); // release the mutex in case of cancellation
331 vlc_cond_wait (&wait, &lock);
333 --- foobar is now true, do something about it here --
335 vlc_cleanup_run (); // release the mutex
338 * @param p_condvar condition variable to wait on
339 * @param p_mutex mutex which is unlocked while waiting,
340 * then locked again when waking up.
341 * @param deadline <b>absolute</b> timeout
343 * @return 0 if the condition was signaled, an error code in case of timeout.
345 void vlc_cond_wait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex)
347 int val = pthread_cond_wait( p_condvar, p_mutex );
348 VLC_THREAD_ASSERT ("waiting on condition");
352 * Waits for a condition variable up to a certain date.
353 * This works like vlc_cond_wait(), except for the additional timeout.
355 * @param p_condvar condition variable to wait on
356 * @param p_mutex mutex which is unlocked while waiting,
357 * then locked again when waking up.
358 * @param deadline <b>absolute</b> timeout
360 * @return 0 if the condition was signaled, an error code in case of timeout.
362 int vlc_cond_timedwait (vlc_cond_t *p_condvar, vlc_mutex_t *p_mutex,
365 #if defined(__APPLE__) && !defined(__powerpc__) && !defined( __ppc__ ) && !defined( __ppc64__ )
366 /* mdate() is mac_absolute_time on OSX, which we must convert to do
367 * the same base than gettimeofday() which pthread_cond_timedwait
369 mtime_t oldbase = mdate();
371 gettimeofday(&tv, NULL);
372 mtime_t newbase = (mtime_t)tv.tv_sec * 1000000 + (mtime_t) tv.tv_usec;
373 deadline = deadline - oldbase + newbase;
375 lldiv_t d = lldiv( deadline, CLOCK_FREQ );
376 struct timespec ts = { d.quot, d.rem * (1000000000 / CLOCK_FREQ) };
378 int val = pthread_cond_timedwait (p_condvar, p_mutex, &ts);
379 if (val != ETIMEDOUT)
380 VLC_THREAD_ASSERT ("timed-waiting on condition");
385 * Initializes a semaphore.
387 void vlc_sem_init (vlc_sem_t *sem, unsigned value)
389 if (sem_init (sem, 0, value))
394 * Destroys a semaphore.
396 void vlc_sem_destroy (vlc_sem_t *sem)
398 int val = sem_destroy (sem);
399 VLC_THREAD_ASSERT ("destroying semaphore");
403 * Increments the value of a semaphore.
405 int vlc_sem_post (vlc_sem_t *sem)
407 int val = sem_post (sem);
408 if (val != EOVERFLOW)
409 VLC_THREAD_ASSERT ("unlocking semaphore");
414 * Atomically wait for the semaphore to become non-zero (if needed),
415 * then decrements it.
417 void vlc_sem_wait (vlc_sem_t *sem)
421 val = sem_wait (sem);
422 while (val == EINTR);
423 VLC_THREAD_ASSERT ("locking semaphore");
427 * Initializes a read/write lock.
429 void vlc_rwlock_init (vlc_rwlock_t *lock)
431 if (pthread_rwlock_init (lock, NULL))
436 * Destroys an initialized unused read/write lock.
438 void vlc_rwlock_destroy (vlc_rwlock_t *lock)
440 int val = pthread_rwlock_destroy (lock);
441 VLC_THREAD_ASSERT ("destroying R/W lock");
445 * Acquires a read/write lock for reading. Recursion is allowed.
447 void vlc_rwlock_rdlock (vlc_rwlock_t *lock)
449 int val = pthread_rwlock_rdlock (lock);
450 VLC_THREAD_ASSERT ("acquiring R/W lock for reading");
454 * Acquires a read/write lock for writing. Recursion is not allowed.
456 void vlc_rwlock_wrlock (vlc_rwlock_t *lock)
458 int val = pthread_rwlock_wrlock (lock);
459 VLC_THREAD_ASSERT ("acquiring R/W lock for writing");
463 * Releases a read/write lock.
465 void vlc_rwlock_unlock (vlc_rwlock_t *lock)
467 int val = pthread_rwlock_unlock (lock);
468 VLC_THREAD_ASSERT ("releasing R/W lock");
472 * Allocates a thread-specific variable.
473 * @param key where to store the thread-specific variable handle
474 * @param destr a destruction callback. It is called whenever a thread exits
475 * and the thread-specific variable has a non-NULL value.
476 * @return 0 on success, a system error code otherwise. This function can
477 * actually fail because there is a fixed limit on the number of
478 * thread-specific variable in a process on most systems.
480 int vlc_threadvar_create (vlc_threadvar_t *key, void (*destr) (void *))
482 return pthread_key_create (key, destr);
485 void vlc_threadvar_delete (vlc_threadvar_t *p_tls)
487 pthread_key_delete (*p_tls);
491 * Sets a thread-specific variable.
492 * @param key thread-local variable key (created with vlc_threadvar_create())
493 * @param value new value for the variable for the calling thread
494 * @return 0 on success, a system error code otherwise.
496 int vlc_threadvar_set (vlc_threadvar_t key, void *value)
498 return pthread_setspecific (key, value);
502 * Gets the value of a thread-local variable for the calling thread.
503 * This function cannot fail.
504 * @return the value associated with the given variable for the calling
505 * or NULL if there is no value.
507 void *vlc_threadvar_get (vlc_threadvar_t key)
509 return pthread_getspecific (key);
512 static bool rt_priorities = false;
513 static int rt_offset;
515 void vlc_threads_setup (libvlc_int_t *p_libvlc)
517 static vlc_mutex_t lock = VLC_STATIC_MUTEX;
518 static bool initialized = false;
520 vlc_mutex_lock (&lock);
521 /* Initializes real-time priorities before any thread is created,
522 * just once per process. */
526 if (config_GetInt (p_libvlc, "rt-priority"))
529 rt_offset = config_GetInt (p_libvlc, "rt-offset");
530 rt_priorities = true;
534 vlc_mutex_unlock (&lock);
538 * Creates and starts new thread.
540 * @param p_handle [OUT] pointer to write the handle of the created thread to
541 * @param entry entry point for the thread
542 * @param data data parameter given to the entry point
543 * @param priority thread priority value
544 * @return 0 on success, a standard error code on error.
546 int vlc_clone (vlc_thread_t *p_handle, void * (*entry) (void *), void *data,
552 pthread_attr_init (&attr);
554 /* Block the signals that signals interface plugin handles.
555 * If the LibVLC caller wants to handle some signals by itself, it should
556 * block these before whenever invoking LibVLC. And it must obviously not
557 * start the VLC signals interface plugin.
559 * LibVLC will normally ignore any interruption caused by an asynchronous
560 * signal during a system call. But there may well be some buggy cases
561 * where it fails to handle EINTR (bug reports welcome). Some underlying
562 * libraries might also not handle EINTR properly.
568 sigdelset (&set, SIGHUP);
569 sigaddset (&set, SIGINT);
570 sigaddset (&set, SIGQUIT);
571 sigaddset (&set, SIGTERM);
573 sigaddset (&set, SIGPIPE); /* We don't want this one, really! */
574 pthread_sigmask (SIG_BLOCK, &set, &oldset);
577 #if defined (_POSIX_PRIORITY_SCHEDULING) && (_POSIX_PRIORITY_SCHEDULING >= 0) \
578 && defined (_POSIX_THREAD_PRIORITY_SCHEDULING) \
579 && (_POSIX_THREAD_PRIORITY_SCHEDULING >= 0)
582 struct sched_param sp = { .sched_priority = priority + rt_offset, };
585 if (sp.sched_priority <= 0)
586 sp.sched_priority += sched_get_priority_max (policy = SCHED_OTHER);
588 sp.sched_priority += sched_get_priority_min (policy = SCHED_RR);
590 pthread_attr_setschedpolicy (&attr, policy);
591 pthread_attr_setschedparam (&attr, &sp);
597 /* The thread stack size.
598 * The lower the value, the less address space per thread, the highest
599 * maximum simultaneous threads per process. Too low values will cause
600 * stack overflows and weird crashes. Set with caution. Also keep in mind
601 * that 64-bits platforms consume more stack than 32-bits one.
603 * Thanks to on-demand paging, thread stack size only affects address space
604 * consumption. In terms of memory, threads only use what they need
605 * (rounded up to the page boundary).
607 * For example, on Linux i386, the default is 2 mega-bytes, which supports
608 * about 320 threads per processes. */
609 #define VLC_STACKSIZE (128 * sizeof (void *) * 1024)
612 ret = pthread_attr_setstacksize (&attr, VLC_STACKSIZE);
613 assert (ret == 0); /* fails iif VLC_STACKSIZE is invalid */
616 ret = pthread_create (p_handle, &attr, entry, data);
617 pthread_sigmask (SIG_SETMASK, &oldset, NULL);
618 pthread_attr_destroy (&attr);
623 * Marks a thread as cancelled. Next time the target thread reaches a
624 * cancellation point (while not having disabled cancellation), it will
625 * run its cancellation cleanup handler, the thread variable destructors, and
626 * terminate. vlc_join() must be used afterward regardless of a thread being
629 void vlc_cancel (vlc_thread_t thread_id)
631 pthread_cancel (thread_id);
635 * Waits for a thread to complete (if needed), then destroys it.
636 * This is a cancellation point; in case of cancellation, the join does _not_
639 * A thread cannot join itself (normally VLC will abort if this is attempted).
640 * Also, a detached thread <b>cannot</b> be joined.
642 * @param handle thread handle
643 * @param p_result [OUT] pointer to write the thread return value or NULL
645 void vlc_join (vlc_thread_t handle, void **result)
647 int val = pthread_join (handle, result);
648 VLC_THREAD_ASSERT ("joining thread");
652 * Detaches a thread. When the specified thread completes, it will be
653 * automatically destroyed (in particular, its stack will be reclaimed),
654 * instead of waiting for another thread to call vlc_join(). If the thread has
655 * already completed, it will be destroyed immediately.
657 * When a thread performs some work asynchronously and may complete much
658 * earlier than it can be joined, detaching the thread can save memory.
659 * However, care must be taken that any resources used by a detached thread
660 * remains valid until the thread completes. This will typically involve some
661 * kind of thread-safe signaling.
663 * A thread may detach itself.
665 * @param handle thread handle
667 void vlc_detach (vlc_thread_t handle)
669 int val = pthread_detach (handle);
670 VLC_THREAD_ASSERT ("detaching thread");
674 * Save the current cancellation state (enabled or disabled), then disable
675 * cancellation for the calling thread.
676 * This function must be called before entering a piece of code that is not
677 * cancellation-safe, unless it can be proven that the calling thread will not
679 * @return Previous cancellation state (opaque value for vlc_restorecancel()).
681 int vlc_savecancel (void)
684 int val = pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &state);
686 VLC_THREAD_ASSERT ("saving cancellation");
691 * Restore the cancellation state for the calling thread.
692 * @param state previous state as returned by vlc_savecancel().
693 * @return Nothing, always succeeds.
695 void vlc_restorecancel (int state)
700 val = pthread_setcancelstate (state, &oldstate);
701 /* This should fail if an invalid value for given for state */
702 VLC_THREAD_ASSERT ("restoring cancellation");
704 if (unlikely(oldstate != PTHREAD_CANCEL_DISABLE))
705 vlc_thread_fatal ("restoring cancellation while not disabled", EINVAL,
706 __func__, __FILE__, __LINE__);
708 pthread_setcancelstate (state, NULL);
713 * Issues an explicit deferred cancellation point.
714 * This has no effect if thread cancellation is disabled.
715 * This can be called when there is a rather slow non-sleeping operation.
716 * This is also used to force a cancellation point in a function that would
717 * otherwise "not always" be a one (block_FifoGet() is an example).
719 void vlc_testcancel (void)
721 pthread_testcancel ();
724 void vlc_control_cancel (int cmd, ...)
736 void (*func) (void *);
738 mtime_t value, interval;
743 static void *vlc_timer_do (void *data)
745 struct vlc_timer *timer = data;
747 timer->func (timer->data);
749 vlc_mutex_lock (&timer->lock);
750 assert (timer->users > 0);
751 if (--timer->users == 0)
752 vlc_cond_signal (&timer->wait);
753 vlc_mutex_unlock (&timer->lock);
757 static void *vlc_timer_thread (void *data)
759 struct vlc_timer *timer = data;
760 mtime_t value, interval;
762 vlc_mutex_lock (&timer->lock);
763 value = timer->value;
764 interval = timer->interval;
765 vlc_mutex_unlock (&timer->lock);
773 vlc_mutex_lock (&timer->lock);
774 if (vlc_clone (&th, vlc_timer_do, timer, VLC_THREAD_PRIORITY_INPUT))
781 vlc_mutex_unlock (&timer->lock);
791 * Initializes an asynchronous timer.
792 * @warning Asynchronous timers are processed from an unspecified thread.
793 * Also, multiple occurences of an interval timer can run concurrently.
795 * @param id pointer to timer to be initialized
796 * @param func function that the timer will call
797 * @param data parameter for the timer function
798 * @return 0 on success, a system error code otherwise.
800 int vlc_timer_create (vlc_timer_t *id, void (*func) (void *), void *data)
802 struct vlc_timer *timer = malloc (sizeof (*timer));
806 vlc_mutex_init (&timer->lock);
807 vlc_cond_init (&timer->wait);
820 * Destroys an initialized timer. If needed, the timer is first disarmed.
821 * This function is undefined if the specified timer is not initialized.
823 * @warning This function <b>must</b> be called before the timer data can be
824 * freed and before the timer callback function can be unloaded.
826 * @param timer timer to destroy
828 void vlc_timer_destroy (vlc_timer_t timer)
830 vlc_timer_schedule (timer, false, 0, 0);
831 vlc_mutex_lock (&timer->lock);
832 while (timer->users != 0)
833 vlc_cond_wait (&timer->wait, &timer->lock);
834 vlc_mutex_unlock (&timer->lock);
836 vlc_cond_destroy (&timer->wait);
837 vlc_mutex_destroy (&timer->lock);
842 * Arm or disarm an initialized timer.
843 * This functions overrides any previous call to itself.
845 * @note A timer can fire later than requested due to system scheduling
846 * limitations. An interval timer can fail to trigger sometimes, either because
847 * the system is busy or suspended, or because a previous iteration of the
848 * timer is still running. See also vlc_timer_getoverrun().
850 * @param timer initialized timer
851 * @param absolute the timer value origin is the same as mdate() if true,
852 * the timer value is relative to now if false.
853 * @param value zero to disarm the timer, otherwise the initial time to wait
854 * before firing the timer.
855 * @param interval zero to fire the timer just once, otherwise the timer
856 * repetition interval.
858 void vlc_timer_schedule (vlc_timer_t timer, bool absolute,
859 mtime_t value, mtime_t interval)
861 static vlc_mutex_t lock = VLC_STATIC_MUTEX;
863 vlc_mutex_lock (&lock);
864 vlc_mutex_lock (&timer->lock);
867 vlc_mutex_unlock (&timer->lock);
868 vlc_cancel (timer->thread);
869 vlc_join (timer->thread, NULL);
870 vlc_mutex_lock (&timer->lock);
874 && (vlc_clone (&timer->thread, vlc_timer_thread, timer,
875 VLC_THREAD_PRIORITY_INPUT) == 0))
877 timer->value = (absolute ? 0 : mdate ()) + value;
878 timer->interval = interval;
880 vlc_mutex_unlock (&timer->lock);
881 vlc_mutex_unlock (&lock);
885 * Fetch and reset the overrun counter for a timer.
886 * @param timer initialized timer
887 * @return the timer overrun counter, i.e. the number of times that the timer
888 * should have run but did not since the last actual run. If all is well, this
891 unsigned vlc_timer_getoverrun (vlc_timer_t timer)
895 vlc_mutex_lock (&timer->lock);
896 ret = timer->overruns;
898 vlc_mutex_unlock (&timer->lock);