title: COM multiple interface inheritance
body: <p>I recently came on a quote in Essential com book by Don box</p>
  <blockquote>
  <p>interface ICatDog : ICat, IDog { // illegal, multiple bases</p>
  </blockquote>
  <blockquote>
  <p>COM prohibits multiple interface inheritance for a variety of reasons. One
  reason is that the binary representation of the resultant C++ abstract base
  class would not be compiler invariant</p>
  </blockquote>
  <p>I was wondering if anyone knows why multiple bases is bad for com and would break compiler invariance.</p>
  <p>Thank you</p>