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sem_acquire

(PHP 4, PHP 5, PHP 7, PHP 8)

sem_acquire — Acquire a semaphore

Description

sem_acquire(SysvSemaphore $semaphore, bool $non_blocking = false): bool

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.

Parameters

semaphore

semaphore is a semaphore obtained from sem_get().

non_blocking

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 acquired.

Return Values

Returns true on success or false on failure.

Changelog

Version Description
8.0.0 semaphore expects a SysvSemaphore instance now; previously, a resource was expected.

See Also

© 1997–2025 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/function.sem-acquire.php