The WeakReference class

(PHP 7 >= 7.4.0)

Einführung

Weak references allow the programmer to retain a reference to an object which does not prevent the object from being destroyed. They are useful for implementing cache like structures.

Hinweis:

The class WeakReference is not to be confused with the class WeakRef of the Weakref extension.

WeakReferences cannot be serialized.

Klassenbeschreibung

WeakReference {
/* Methoden */
public __construct ( )
public static create ( object $referent ) : WeakReference
public get ( ) : object|null
}

WeakReference Examples

Beispiel #1 Basic WeakReference Usage

<?php
$obj = new stdClass;
$weakref = WeakReference::create($obj);
var_dump($weakref->get());
unset($obj);
var_dump($weakref->get());
?>

Das oben gezeigte Beispiel erzeugt eine ähnliche Ausgabe wie:

object(stdClass)#1 (0) {
}
NULL

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