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PTHREAD_MUTEX_UNLOCK(3) Library Functions Manual PTHREAD_MUTEX_UNLOCK(3)

pthread_mutex_unlock —
unlock a mutex

#include <pthread.h>

int
pthread_mutex_unlock(pthread_mutex_t *mutex);

If the current thread holds the lock on mutex, then the pthread_mutex_unlock() function unlocks mutex.

If successful, pthread_mutex_unlock() will return zero, otherwise an error number will be returned to indicate the error.

pthread_mutex_unlock() will fail if:
[]
The value specified by mutex is invalid.
[]
The current thread does not hold a lock on mutex.

pthread_mutex_destroy(3), pthread_mutex_init(3), pthread_mutex_lock(3)

pthread_mutex_unlock() conforms to ISO/IEC 9945-1:1996 (“POSIX.1”).
June 5, 2013 OpenBSD-current