3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php function f($a) { if ($a > 0) { $b = f($a-1); } return $b; } echo f(1);
Output for 5.5.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
Notice: Undefined variable: b in /in/4m0HZ on line 6
Output for 4.3.0 - 5.4.45