(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.
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