3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $a = 1; $$a = 1; ${++$a} = 2; var_dump(${1}); var_dump($a); var_dump(${2});
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
int(1) int(2) int(2)