... Next . 3.0.6 - 3.0.18 only, PHP 4 >= 4.0.0) sem_get -- Get a semaphore id . int sem_get ( int key [, int max_acquire [, int perm]]) . Returns: A positive semaphore identifier on success, or FALSE on error. sem_get() returns an id that can be used to access the System V semaphore with the given key. ... A second call to sem_get() for the same key will return a different semaphore identifier, but both identifiers access the same underlying semaphore. ...