3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $a = new stdClass; var_dump(call_user_func('call_user_func','exec','id',$a));
based on HrgJV
Output for 7.1.0 - 7.2.0
Warning: Parameter 2 to exec() expected to be a reference, value given in /in/NrnJm on line 4 string(0) ""
Output for 5.3.0 - 7.0.20
Warning: Parameter 2 to exec() expected to be a reference, value given in /in/NrnJm on line 4 NULL
Output for 4.3.0 - 5.2.17
string(0) ""