3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php if (defined('HHVM_VERSION')) { exit('*HHVM skipped*'); } // The following line will emit some error if key()'s argument cannot be passed by value var_dump(key(array_flip(array('foo' => 'bar'))));
Output for 4.3.0 - 5.0.4, 5.1.0 - 5.6.30, 7.0.0 - 7.2.6
string(3) "bar"
Output for hhvm-3.10.1 - 3.17.3
*HHVM skipped*
Output for 5.0.5
Fatal error: Only variables can be passed by reference in /in/BPuff on line 8
Process exited with code 255.