3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $conversion = pack ("H", 255); echo $conversion{1};
Output for 5.2.10 - 7.2.0
Notice: Uninitialized string offset: 1 in /in/r7b9l on line 4
Output for 4.3.0 - 5.2.9
Notice: Uninitialized string offset: 1 in /in/r7b9l on line 4