The WeakReference class

Introduction

(PHP 7 >= 7.4.0, PHP 8)

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. If the original object has been destroyed, null will be returned when calling the WeakReference::get() method. The original object will be destroyed when the refcount for it drops to zero; creating weak references does not increase the refcount of the object being referenced.

WeakReferences cannot be serialized.

Class synopsis

public static create(object $object): WeakReference

public get(): ?object

WeakReference Examples

<?php

$obj = new stdClass();
$weakref = WeakReference::create($obj);

var_dump($weakref->get());

unset($obj);

var_dump($weakref->get());

?>

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

Changelog

Table of Contents

• WeakReference::__construct — Constructor that disallows instantiation
• WeakReference::create — Create a new weak reference
• WeakReference::get — Get a weakly referenced Object