<?php
class A {
    public function __call($m, $a) {
        echo "__call\n";
    }
}

class B extends A {
    public static function foo() {
        echo "foo\n";
    }
}

if (is_callable(array('B', 'foo'))) {
    call_user_func(array('B', 'foo'));
}
if (is_callable(array('A', 'foo'))) {
    call_user_func(array('A', 'foo'));
}
?>