<?php class Base { public $aaa = 1; protected $bbb = 2; private $ccc = 3; } class Child extends Base { public $ddd = 4; protected $eee = 5; private $fff = 6; function foo($obj) { var_dump(get_class($obj)); var_dump(get_object_vars($obj)); } } $child_obj = new Child(); $base_obj = new Base(); $child_obj->foo($base_obj);