sem_get() returns an id that can be used to
access the System V semaphore with the given
The semaphore is created if necessary using the permission bits specified in
perm (defaults to 0666). The number of processes that can
acquire the semaphore simultaneously is set to
(defaults to 1). Actually this value is set only if the process
finds it is the only process currently attached to the semaphore.
auto_release specifies if the
semaphore should be automatically released on request shutdown.
It is available since PHP 4.3.0.
Returns a positive semaphore identifier on success, or FALSE on error.
A second call to sem_get() for the same key will return a different semaphore identifier, but both identifiers access the same underlying semaphore.