- var_dump: documentation ( source)
<?php
$d1 = new DateTime('2014+02:00');
$d2 = new DateTime('2014');
$d3 = new DateTime('2014', $d1->getTimeZone());
$d2->setTimeZone($d1->getTimeZone());
var_dump($d1->getTimestamp());
var_dump($d2->getTimestamp());
var_dump($d3->getTimestamp());