3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $start = new \DateTime('midnight first day of this month'); var_dump($start->format('m d Y H i s'));
based on IrvYb
Output for 5.3.20 - 5.4.45, 5.6.28, 7.0.20 - 7.2.0
string(19) "12 01 2015 00 00 00"
Output for 5.5.24, 5.5.35, 5.6.21, 7.0.6
string(19) "05 01 2016 00 00 00"
Output for 5.5.25 - 5.5.30, 5.5.34, 5.6.8 - 5.6.14, 5.6.20, 7.0.5
string(19) "04 01 2016 00 00 00"
Output for 5.5.31 - 5.5.33, 5.6.15 - 5.6.19, 7.0.0 - 7.0.4
string(19) "03 01 2016 00 00 00"