Predefined Interfaces and Classes
PHP Manual

The WeakReference class

Introduction

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.

WeakReferences cannot be serialized.

Class synopsis

final WeakReference
/* Methods */
public __construct()
public static WeakReference create(object $object)
public objectnull get()

WeakReference Examples

Example #1 Basic WeakReference Usage

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

The above example will output something similar to:

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

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