- var_dump: documentation ( source)
- spl_object_hash: documentation ( source)
<?php
$o1 = (object) array('a' => 1);
$h1 = spl_object_hash($o1);
unset($o1);
$o2 = (object) array('b' => 1);
$h2 = spl_object_hash($o2);
echo "$h1\n$h2";
var_dump($h1 === $h2);