call_user_func 사용자가 정의한 함수를 호출하여 실행고자 할 때 사용

mixed call_user_func ( callback $callback [, mixed $parameter [, mixed $... ]] )

<?php
function barber($type)
{
    echo "You wanted a $type haircut, no problem\n";
}
call_user_func('barber', "mushroom");
call_user_func('barber', "shave");
?>

You wanted a mushroom haircut, no problem
You wanted a shave haircut, no problem