3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php echo substr('abcdefgh', -4, -2); print_r($r);
based on LkXHE
Output for 5.0.4 - 7.2.0
ef Notice: Undefined variable: r in /in/8Pm9W on line 5
Output for 4.3.0 - 5.0.3
ef Notice: Undefined variable: r in /in/8Pm9W on line 5