3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $a = null; if (!is_null($b)) echo "$a is not null";
Output for 5.0.4 - 7.2.0
Notice: Undefined variable: b in /in/8BXKl on line 3
Output for 4.3.0 - 5.0.3
Notice: Undefined variable: b in /in/8BXKl on line 3