sem_acquire Acquire a semaphore boolsem_acquire intsem_identifier 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. &return.success; 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.