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sem_acquire

(PHP 4, PHP 5, PHP 7)

sem_acquire — Acquire a semaphore

Description

代码语言:javascript
复制
bool sem_acquire ( resource $sem_identifier [, bool $nowait = false ] )

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

sem_identifier

sem_identifier is a semaphore resource, obtained from sem_get().

nowait

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

5.6.1

The $nowait parameter was added.

See Also

  • sem_get() - Get a semaphore id
  • sem_release() - Release a semaphore

← msg_stat_queue

sem_get →

代码语言:txt
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 ? 1997–2017 The PHP Documentation Group

Licensed under the Creative Commons Attribution License v3.0 or later.

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