PTHREAD_MUTEX_UNLOCK(3)  BSD Library Functions Manual  PTHREAD_MUTEX_UNLOCK(3)

NAME
     pthread_mutex_unlock -- unlock a mutex

SYNOPSIS
     #include <pthread.h>

     int
     pthread_mutex_unlock(pthread_mutex_t *mutex);

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

     Calling pthread_mutex_unlock() with a mutex that the calling thread does
     not hold will result in undefined behavior.

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

ERRORS
     The pthread_mutex_unlock() function will fail if:

     [EINVAL]           The value specified by mutex is invalid.

     [EPERM]            The current thread does not hold a lock on mutex.

SEE ALSO
     pthread_mutex_destroy(3), pthread_mutex_init(3), pthread_mutex_lock(3),
     pthread_mutex_trylock(3)

STANDARDS
     The pthread_mutex_unlock() function conforms to ISO/IEC 9945-1:1996
     (``POSIX.1'').

BSD                              July 30, 1998                             BSD