(PECL sync >= 1.0.0)
SyncSemaphore::unlock — Increases the count of the semaphore
&$prevcount = ?): boolIncreases the count of a SyncSemaphore object.
prevcountReturns the previous count of the semaphore.
成功时返回 true， 或者在失败时返回 false。
示例 #1 SyncSemaphore::unlock() example
<?php
$semaphore = new SyncSemaphore("LimitedResource_2clients", 2);
if (!$semaphore->lock(3000))
{
echo "Unable to lock semaphore.";
exit();
}
/* ... */
$semaphore->unlock();
?>