(PHP 4, PHP 5, PHP 7, PHP 8)
sem_acquire — Acquire a semaphore
sem_acquire() by default 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.
After processing a request, any semaphores acquired by the process but not explicitly released will be released automatically and a warning will be generated.
semaphore is a semaphore
obtained from sem_get().
Specifies if the process shouldn't wait for the semaphore to be acquired.
If set to
true, the call will return
false immediately if a semaphore cannot be immediately