(PECL weakref >= 0.1.0)
The WeakRef class provides a gateway to objects without preventing the garbage collector from freeing those objects. It also provides a way to turn a weak reference into a strong one.
Note:
The class WeakRef is not to be confused with the class WeakReference.
Example #1 WeakRef usage example
<?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";
}
?>
以上例程会输出：
Object still exists!
object(MyClass)#1 (0) {
}
Destroying object!
Object is dead!