3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $value = null; system('w', $value); var_dump($value);
Output for 4.3.0 - 5.6.28, 7.0.0 - 7.1.0
int(127)
Output for hhvm-3.10.0 - 3.12.0
Failed to exec: `w' int(1)