3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $a = 'b'; var_dump(debug_zval_dump($a));
Output for hhvm-3.12.0, 7.0.0 - 7.1.0
string(1) "b" refcount(1) NULL
Output for hhvm-3.10.0

Process exited with code 153.
Output for 4.3.0 - 5.6.28
string(1) "b" refcount(2) NULL