COM inheritance Q

[Ann and Jason Edmeades]

>Jason seems to have:
>- IWineD3DSurface inherits from IWineD3DResource  
>- IWineD3DResource inherits from IUnknown

Yep...

>Jason, why IWineD3DSurface inherits from IWineD3DResource ?

Well wine has 

/***************************************************************************
**
 * IDirect3DSurface9 interface
 */
#define INTERFACE IDirect3DSurface9
DECLARE_INTERFACE_(IDirect3DSurface9,IDirect3DResource9)
{

and the dxsdk

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/directx9_c/
directx/graphics/reference/d3d/interfaces/idirect3dsurface9/_idirect3dsurfac
e9.asp

states

Inherits from IDirect3DResource9

(See the table)

I think the sdk includes also do it this way

Jason