3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $array = array('foo' => array('bar')); var_dump(key(key($array)));
based on mar9m
Output for 5.3.0 - 7.2.0
Warning: key() expects parameter 1 to be array, string given in /in/vjbt9 on line 3 NULL
Output for 4.3.2 - 5.0.4, 5.1.0 - 5.2.17
Warning: key(): Passed variable is not an array or object in /in/vjbt9 on line 3 bool(false)
Output for 5.0.5
Fatal error: Only variables can be passed by reference in /in/vjbt9 on line 3
Process exited with code 255.
Output for 4.3.0 - 4.3.1
Warning: key() [http://www.php.net/function.key]: Passed variable is not an array or object in /in/vjbt9 on line 3 bool(false)