php man page for weakref

WEAKREF(3)								 1								WEAKREF(3)

The WeakRef class

INTRODUCTION
	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.

CLASS SYNOPSIS
       WeakRef

       WeakRef

       Methods

       o public Weakref::__construct (object  $object)

       o public bool Weakref::acquire (void  )

       o public object Weakref::get (void  )

       o public bool Weakref::release (void  )

       o public bool Weakref::valid (void  )

EXAMPLES
       Example #1

	      WeakRef usage example

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

	      $o1 = new MyClass;

	      $r1 = new WeakRef($o1);

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

	      unset($o1);

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

	      The above example will output:

	      Object still exists!
	      object(MyClass)#1 (0) {
	      }
	      Destroying object!
	      Object is dead!

PHP Documentation Group 														WEAKREF(3)