Re: Cannot create the object

Barzo <dbarzo@gmail.com> wrote:


Sometimes you end up deriving from an interface more than once,
indirectly:

interface ICommon {...};
interface IItf1 : public ICommon {...};
interface IItf2 : public ICommon {...};

class MyObject : public IItf1, public IItf2 {...};

In this case, the compiler needs help deciding which of the two
instances to return when queried for ICommon: note that

(ICommon*)(IItf1*)this

and

(ICommon*)(IItf2*)this

are two distinct pointers with different values. To disambiguate, you do

COM_INTERFACE_ENTRY2(ICommon, IItf1)

--
With best wishes,
    Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925