3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $vars = get_defined_vars(); $mystring = null; $vars = @array_diff(get_defined_vars(),$vars); echo '<pre>'; print_r($vars); echo '</pre>';
Output for 4.3.0 - 5.6.28, 7.0.0 - 7.1.0
<pre>Array ( [mystring] => ) </pre>
Output for hhvm-3.10.0 - 3.12.0
<pre>Array ( ) </pre>