3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php function my_callback_function() { echo 'hello world!'; } call_user_func('my_callback_function');
Output for 4.3.0 - 5.6.28, hhvm-3.12.0, 7.0.0 - 7.1.0
hello world!
Output for hhvm-3.10.0

Process exited with code 153.