sem_acquire Acquire a semaphore boolsem_acquire resourcesem_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 maximum number of semaphore to be exceeded. sem_identifier is a semaphore resource, obtained from sem_get. &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.