3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $n = null; echo debug_zval_dump($n);
Output for 7.0.0 - 7.1.0
NULL
Output for hhvm-3.12.0
NULL refcount(1)
Output for hhvm-3.10.0

Process exited with code 153.
Output for 4.3.0 - 5.6.28
NULL refcount(2)