inherited method call - I got it!

First, thank all of you for your guess & tips.

It wouldn't be so weird to find the right answer if I was thinking about the similarity of PHP and C++ syntax.

and one more pleasure, function overriding is enable and working correctly and all the functions are virtual! OO support of PHP is great! (except multiple inheritance)

So I 've got the answer, look:

class A {
// you've already known it!
}

class B extends A
{
function f1($x)
{
A::f1($x*4); // ancestor class name double colon as the same in C++
$this->x *= 2;
}
}