(PHP 3>= 3.0.6, PHP 4 >= 4.0.0)

sem_acquire -- Acquire a semaphore


bool sem_acquire (int sem_identifier)

Returns: TRUE on success, FALSE on error.

sem_acquire() blocks (if necessary) until the semaphore can be acquired. A process attempting to acquire a semaphore which it has already acquired will block forever if acquiring the semaphore would cause its max_acquire value to be exceeded.

After processing a request, any semaphores acquired by the process but not explicitly released will be released automatically and a warning will be generated.

See also: sem_get() and sem_release().