3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $a = null; echo strtoupper($a);
Output for 4.3.0 - 5.6.28, hhvm-3.10.0, 7.0.0 - 7.1.0
Output for hhvm-3.12.0 - 3.13.2
Warning: strtoupper() expects parameter 1 to be string, null given in /in/50HY6 on line 5