Re: error MIDL2025 : syntax error : expecting { near ","

"Igor Tandetnik" <>
Tue, 21 Aug 2007 14:38:26 -0400
Donos <> wrote:

Now is a more tricky question, i guess

interface IVehicle : IUnknown

interface ICar : IVehicle

interface IHonda : ICar

interface IToyota : ICar

In this case, should i contunue to derive from both IHonda and

And should i keep all interfaces in COM MAP Entry?

You should derive both from IHonda and IToyota. You should use
COM_INTERFACE_ENTRY2 to list ICar in an interface map (choose either
IHonda or IToyota to disambiguate, it doesn't matter which).

Better still, you should sit and think why you feel you need such a
complicated inheritance hierarchy. While looking great in a textbook, in
most practical situations an inheritance hierarchy more than two levels
deep is a sign of bad design.

COM interfaces should not model entities - they should model sets of
behaviors. What can ICar do that IVehicle can't? Break this
functionality into a separate interface (e.g. ICarLike) derived directly
from IUnknown, and have the COM object implement both side by side.
With best wishes,
    Igor Tandetnik

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