Get number of days for previous month

I’m using this code to get number of days in last month, but if the current month is January (01) it’s going to use 00 month instead of 12.

$prev_month_days = cal_days_in_month(CAL_GREGORIAN, date('m')-1, date('Y'));

Searched Google for 20 minutes and could not find any reasonable and shorthand solution.

Please help. Thanks.

Answer

<?php 

echo date("t", mktime(0,0,0, date("n") - 1));

?>