(PHP 3 >= 3.0.6, PHP 4, PHP 5)
sem_acquire -- Acquire a semaphore
Description
bool
sem_acquire ( resource sem_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 ressource,
obtained from sem_get().
如果成功则返回 TRUE，失败则返回 FALSE。
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().
msg_stat_queue