Lock

A lock is a mechanism used to control access to a shared resource so that only one process (or script) can use it at a time.

There are different kind of lock:

• file locks, when using flock() function

• database locks, via transactions or explicit locks in the database

• semaphore locks, based on sem extension.

<?php

$sem = sem_get(123456);

sem_acquire($sem);
// critical section
sem_release($sem);

?>

See also Data locking strategies in PHP apps. Practical approach and Locking in PHP to serialize execution of critical sections.

Related : Atomic Operation, File Mode, file_put_contents(), Race Condition

Related packages : php-lock/lock