sem_get
(PHP 4, PHP 5)
sem_get — Get a semaphore id
说明
resource sem_get ( int $key [, int $max_acquire = 1 [, int $perm = 0666 [, int $auto_release = 1 ]]] )sem_get() returns an id that can be used to access the System V semaphore with the given key.
A second call to sem_get() for the same key will return a different semaphore identifier, but both identifiers access the same underlying semaphore.
参数
- key
-
- max_acquire
-
The number of processes that can acquire the semaphore simultaneously is set to max_acquire.
- perm
-
The semaphore permissions. Actually this value is set only if the process finds it is the only process currently attached to the semaphore.
- auto_release
-
Specifies if the semaphore should be automatically released on request shutdown.
返回值
Returns a positive semaphore identifier on success, or FALSE on error.
更新日志
| 版本 | 说明 |
|---|---|
| 4.3.0 | The auto_release parameter was added. |
参见
- sem_acquire() - Acquire a semaphore
- sem_release() - Release a semaphore
- ftok() - Convert a pathname and a project identifier to a System V IPC key
