SyncSemaphore::__construct

(PECL sync >= 1.0.0)

SyncSemaphore::__construct — Constructs a new SyncSemaphore object

説明

public function SyncSemaphore::__construct(string $name = ?, int $initialval = 1, bool $autounlock = true)

Constructs a named or unnamed semaphore.

パラメータ

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.

戻り値

The new SyncSemaphore object.

エラー / 例外

An exception is thrown if the semaphore cannot be created or opened.

例

例1 SyncSemaphore::__construct() example

<?php
$semaphore = new SyncSemaphore("LimitedResource_2clients", 2);

if (!$semaphore->lock(3000))
{
    echo "Unable to lock semaphore.";

    exit();
}

/* ... */

$semaphore->unlock();
?>

参考

SyncSemaphore::lock() - Decreases the count of the semaphore or waits
SyncSemaphore::unlock() - Increases the count of the semaphore

関連キーワード:

SyncSemaphore semaphore Constructs lock construct autounlock named unlock initialval opened exception thrown script count sync unnamed already exists able current user process running meaningless error message