- var_dump: documentation ( source)
<?php
$s = new SplObjectStorage();
$o1 = new StdClass;
$o2 = new StdClass;
$o3 = new StdClass;
$s->attach($o1);
$s->attach($o2);
$s->attach($o3);
foreach($s as $key=>$val){
echo 'key='.$key.' val='.var_dump($val).PHP_EOL;
}