3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $a = mb_strtolower(null); var_dump($a);
Output for 5.6.0 - 5.6.30, hhvm-3.21.3 - 3.22.0, 7.0.0 - 7.3.0beta1
string(0) ""
Output for hhvm-3.18.5
Warning: mb_strtolower() expects parameter 1 to be string, null given in /in/C2d1H on line 3 NULL