Under what conditions will the IUnknown::AddRef method return 0?

Raymond Chen March 12, 2015 Mar 12, 2015 03/12/15

A customer was debugging their application and discovered that for one of the objects they were using, the IUnknown::Add­Ref method returns 0. How is that possible? That would imply that the object's reference count was originally negative one? The return value from IUnknown::Add­Ref is the object reference count by convention, but ...