3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php if (undefined == $_SESSION) { echo 'null true'; } ?>
Output for 7.2.0 - 7.3.0alpha1
Warning: Use of undefined constant undefined - assumed 'undefined' (this will throw an Error in a future version of PHP) in /in/Y0avL on line 3 Notice: Undefined variable: _SESSION in /in/Y0avL on line 3
Output for 5.0.4 - 7.1.10
Notice: Use of undefined constant undefined - assumed 'undefined' in /in/Y0avL on line 3 Notice: Undefined variable: _SESSION in /in/Y0avL on line 3
Output for 4.3.0 - 5.0.3
Notice: Use of undefined constant undefined - assumed 'undefined' in /in/Y0avL on line 3 Notice: Undefined variable: _SESSION in /in/Y0avL on line 3