<?php header("Content-type: text/plain"); class Foo { /** * An indentifier * @var string */ private $name; /** * A reference to another Foo object * @var Foo */ private $link; public function __construct($name) { $this->name = $name; } public function setLink(Foo $link){ $this->link = $link; } public function __destruct() { echo 'Destroying: ', $this->name, PHP_EOL; } } // create two Foo objects: $foo = new Foo('Foo 1'); $bar = new Foo('Foo 2'); // make them point to each other $foo->setLink($bar); $bar->setLink($foo); // destroy the global references to them $foo = null; $bar = null; // we now have no way to access Foo 1 or Foo 2, so they OUGHT to be __destruct()ed // but they are not, so we get a memory leak as they are still in memory. // // Uncomment the next line to see the difference when explicitly calling the GC: gc_collect_cycles(); // // see also: http://www.php.net/manual/en/features.gc.php // // create two more Foo objects, but DO NOT set their internal Foo references // so nothing except the vars $foo and $bar point to them: $foo = new Foo('Foo 3'); $bar = new Foo('Foo 4'); // destroy the global references to them $foo = null; $bar = null; // we now have no way to access Foo 3 or Foo 4 and as there are no more references // to them anywhere, their __destruct() methods are automatically called here, // BEFORE the next line is executed: echo 'End of script', PHP_EOL; ?>
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