3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php var_dump(key(array('1' => '1.1')));
Output for 4.4.1, 5.1.0 - 7.1.7
int(1)
Output for 4.3.2 - 4.4.0, 4.4.2 - 5.0.5
Fatal error: Only variables can be passed by reference in /in/WgBIH on line 4
Process exited with code 255.
Output for 4.3.0 - 4.3.1
Fatal error: Only variables can be passed by reference in /in/WgBIH on line 4