3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php function ack($m, $n) { if (!$m) return ++$n; } echo ack(0, 10);
Output for 4.3.0 - 5.6.28, hhvm-3.12.0, 7.0.0 - 7.1.0
11
Output for hhvm-3.10.0

Process exited with code 153.