PHP 8.4.0 RC4 available for testing

    The WeakReference class

    (PHP 7 >= 7.4.0, PHP 8)

    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. 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

    final class WeakReference {
    /* Methods */
    public __construct()
    public static create(object $object): WeakReference
    public get(): ?object
    }

    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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