3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = function () { echo 'hello'; }; function myfunction(callable $a, callable $b = null) { if (null !== $a) call_user_func($a); if (null !== $b) call_user_func($b); } myfunction($a);
Output for 5.4.8 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.10, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.7
hello
preferences:
196.71 ms | 404 KiB | 219 Q