do need Interfaces for COM

From: vimal (
Date: 05/12/04

Date: 12 May 2004 03:49:38 -0700

Hi ,

I am currently learning COM using c++. Just when I completed the
chapter about Interfaces in Dale Rogerson's Inside COM, i got a basic
question in my mind.
Why do we need Interfaces?? Cant we achieve what Interfaces do by just
exported functions?

As far as i know Interfaces are nothing but placeholders for function
pointers. If this is true why not the QueryInterface function return
the Function pointers instead of Interface pointers??

I appreciate any light on this thought .

Thanks in advance