Pthread_mutex_lock Error Handling
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pthread_mutex_lock(pthread_mutex_t *mutex); int pthread_mutex_trylock(pthread_mutex_t *mutex); int pthread_mutex_unlock(pthread_mutex_t *mutex); DESCRIPTION The mutex object referenced by mutex is locked by calling pthread_mutex_lock(). If the mutex is already locked, the calling thread blocks until the mutex becomes available. This operation returns with the pthread_mutex_lock example mutex object referenced by mutex in the locked state with the calling thread as
Pthread_mutex_lock Return Value
its owner. If the mutex type is PTHREAD_MUTEX_NORMAL, deadlock detection is not provided. Attempting to relock the mutex causes deadlock.
What Is Pthread_mutex_lock
If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, undefined behaviour results. If the mutex type is PTHREAD_MUTEX_ERRORCHECK, then error checking is provided.
Man Pthread_mutex_lock
If a thread attempts to relock a mutex that it has already locked, an error will be returned. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, an error will be returned. If the mutex type is PTHREAD_MUTEX_RECURSIVE, then the mutex maintains the concept of a lock count. When a thread successfully acquires a mutex for the first pthread_mutex_init time, the lock count is set to one. Every time a thread relocks this mutex, the lock count is incremented by one. Each time the thread unlocks the mutex, the lock count is decremented by one. When the lock count reaches zero, the mutex becomes available for other threads to acquire. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, an error will be returned. If the mutex type is PTHREAD_MUTEX_DEFAULT, attempting to recursively lock the mutex results in undefined behaviour. Attempting to unlock the mutex if it was not locked by the calling thread results in undefined behaviour. Attempting to unlock the mutex if it is not locked results in undefined behaviour. The function pthread_mutex_trylock() is identical to pthread_mutex_lock() except that if the mutex object referenced by mutex is currently locked (by any thread, including the current thread), the call returns immediately. The pthread_mutex_unlock() function releases the mutex object referenced by mutex. The manner in which a mutex is released is dependent upon the mutex's type attribute. If there are threads blocked on the mutex object referenced by mutex when pthread_mutex_unlock() is called, resulting in the mutex becoming availab
- lock and unlock a mutex SYNOPSIS [THR] #include <pthread.h>
int pthread_mutex_lock(pthread_mutex_t *mutex);
int pthread_mutex_trylock(pthread_mutex_t *mutex);
int pthread_mutex_unlock(pthread_mutex_t *mutex); pthread_mutex_unlock DESCRIPTION The mutex object referenced by mutex pthread_mutex_lock timeout shall be locked by calling pthread_mutex_lock(). If the mutex is already locked, the calling thread shall block until pthread_mutex_trylock the mutex becomes available. This operation shall return with the mutex object referenced by mutex in the locked state with the calling thread as its owner. [XSI] If the mutex type http://pubs.opengroup.org/onlinepubs/7908799/xsh/pthread_mutex_lock.html is PTHREAD_MUTEX_NORMAL, deadlock detection shall not be provided. Attempting to relock the mutex causes deadlock. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, undefined behavior results. If the mutex type is PTHREAD_MUTEX_ERRORCHECK, then error checking shall be provided. If a thread attempts to relock a mutex that it has already locked, an http://pubs.opengroup.org/onlinepubs/009695399/functions/pthread_mutex_lock.html error shall be returned. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, an error shall be returned. If the mutex type is PTHREAD_MUTEX_RECURSIVE, then the mutex shall maintain the concept of a lock count. When a thread successfully acquires a mutex for the first time, the lock count shall be set to one. Every time a thread relocks this mutex, the lock count shall be incremented by one. Each time the thread unlocks the mutex, the lock count shall be decremented by one. When the lock count reaches zero, the mutex shall become available for other threads to acquire. If a thread attempts to unlock a mutex that it has not locked or a mutex which is unlocked, an error shall be returned. If the mutex type is PTHREAD_MUTEX_DEFAULT, attempting to recursively lock the mutex results in undefined behavior. Attempting to unlock the mutex if it was not locked by the calling thread results in undefined behavior. Attempting to unlock the mutex if it is not locked results in undefined behavior. The pthread_mutex_trylock() fun
the interface may not be implemented on Linux. Name pthread_mutex_lock, pthread_mutex_trylock, pthread_mutex_unlock - lock and unlock a mutex Synopsis #include