date - PHP dateperiod function does not return anything -

i need find dates between set of dates, trying use dateperiod it. began trying sample code:

$start = new datetime('2012-07-01'); $interval = new dateinterval('p7d'); $end = new datetime('2012-07-31');  $period = new dateperiod($start, $interval, $end,dateperiod::exclude_start_date); var_dump($period); 

the datetime , dateinterval objects var_dump correct data. dateperiod object not give me range! object(dateperiod)#5 (0) {}

this works fine in laptop, date range returned. issue when run in server. php version in server 5.3.3. php site states dateperiod needs php >-5.3.0.

does have suggestions on whats going on here? appreciated!

prior php version 5.4.17, internals of dateperiod object "hidden", , wouldn't reveal when var_dumped.

however, still iterable, foreach loop on dateperiod object still return series of dates period