- var_dump: documentation ( source)
<?php
$a = new StdClass;
$b = null;
var_dump(!$a);
var_dump(!$b instanceof StdClass);
var_dump(!$a instanceof StdClass);
var_dump(!($b instanceof StdClass));
var_dump(!($a instanceof StdClass));
var_dump($b instanceof StdClass);
var_dump($a instanceof StdClass);