SyncSemaphore::__construct
(PECL sync >= 1.0.0)
SyncSemaphore::__construct — Constructs a new SyncSemaphore object
说明
Constructs a named or unnamed semaphore.
参数
-
name -
The name of the semaphore if this is a named semaphore object.
注意:
If the name already exists, it must be able to be opened by the current user that the process is running as or an exception will be thrown with a meaningless error message.
-
initialval -
The initial value of the semaphore. This is the number of locks that may be obtained.
-
autounlock -
Specifies whether or not to automatically unlock the semaphore at the conclusion of the PHP script.
警告If an object is: A named semaphore with an autounlock of
false, the object is locked, and the PHP script concludes before the object is unlocked, then the underlying semaphore will end up in an inconsistent state.
返回值
The new SyncSemaphore object.
错误／异常
An exception is thrown if the semaphore cannot be created or opened.
示例
示例 #1 SyncSemaphore::__construct() example
<?php
$semaphore = new SyncSemaphore("LimitedResource_2clients", 2);
if (!$semaphore->lock(3000))
{
echo "Unable to lock semaphore.";
exit();
}
/* ... */
$semaphore->unlock();
?>参见
- SyncSemaphore::lock() - Decreases the count of the semaphore or waits
- SyncSemaphore::unlock() - Increases the count of the semaphore
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