3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $var = 4; function double(&$var){ $var = $var * 2; } double($var); print_r($var);
Output for 5.6.0 - 5.6.30, hhvm-3.15.4, 7.0.0 - 7.2.0
8