3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $int=1 ; var_dump( strpos(log(($int^pow(2,ceil(log($int, 2)))-1)+1,2),'.'));
Output for 4.3.0 - 5.6.21, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
bool(false)