PHP Functions Essential Reference

sem_acquire

bool sem_acquire(int id) 

Acquires the semaphore identified by id.

Returns:

TRUE on success; FALSE on failure

Description:

sem_acquire() attempts to acquire the semaphore identified by id , and blocks until it can do so. Remember that a semaphore can be simultaneously acquired only as many times as specified in the max_acquire parameter to sem_get(); if this limit has been reached, sem_acquire blocks until the semaphore is released. id must be a valid semaphore identifier as returned by sem_get().

Version:

PHP 3 since 3.0.6, PHP 4

See also:

sem_get() 
sem_release() 

Example:

Simple multiple-script lock blocking

/* To test this script, create two browser windows and load the * page containing this script in each of them simultaneously. ...