1.2.1621. ext/weakref

Weak References for PHP.

Weak references provide a non-intrusive gateway to ephemeral objects. Unlike normal (strong) references, weak references do not prevent the garbage collector from freeing that object. For this reason, an object may be destroyed even though a weak reference to that object still exists. In such conditions, the weak reference seamlessly becomes invalid.

<?php
class MyClass {
    public function __destruct() {
        echo "Destroying object!\n";
    }
}

$o1 = new MyClass;

$r1 = new WeakRef($o1);

if ($r1->valid()) {
    echo "Object still exists!\n";
    var_dump($r1->get());
} else {
    echo "Object is dead!\n";
}

unset($o1);

if ($r1->valid()) {
    echo "Object still exists!\n";
    var_dump($r1->get());
} else {
    echo "Object is dead!\n";
}
?>

See also Weak references and PECL extension that implements weak references and weak maps in PHP.

1.2.1621.1. Specs

Short name	Extensions/Extweakref
Rulesets	All, Appinfo, CE, Changed Behavior
Exakat since	1.6.5
PHP Version	All
Severity
Time To Fix
Precision	Very high
Available in	Entreprise Edition, Community Edition, Exakat Cloud