Re: [v2 PATCH] include/wincodec.idl: Stop redefinition of ID2D1Image

[Vincent Povirk]

Why can't we handle this the way that d2d1.idl does? It doesn't
include wincodec.idl, but it declares the interfaces it uses from
there.

I know the Windows SDK doesn't do that, but that's probably because
the SDK headers are weird and don't declare the d2d1 interfaces in an
idl.

[v2 PATCH] include/wincodec.idl: Stop redefinition of ID2D1Image

[Alistair Leslie-Hughes]

From: wine-devel  on behalf of Vincent Povirk 
Sent: Friday, 16 June 2017 2:49 AM
To: [e-mail]
Subject: Re: [v2 PATCH] include/wincodec.idl: Stop redefinition of ID2D1Image
> Why can't we handle this the way that d2d1.idl does? It doesn't
> include wincodec.idl, but it declares the interfaces it uses from
> there.

We cannot use "interface ID2D1Image;" like in d2d1.idl.  This is just a forward declare and causes compile errors when building d3dx* with
../../include/wincodec.h:5800:9: error: unknown type name ‘ID2D1Image’ ID2D1Image *image

I only see two options, 
1. Use the d2d1.idl, which will include extra interfaces not in the original
or
2. Add the following to the wincodec.idl.

#ifndef __ID2D1Image_FWD_DEFINED__
#define __ID2D1Image_FWD_DEFINED__
typedef interface ID2D1Image ID2D1Image;
#ifdef __cplusplus
interface ID2D1Image;
#endif /* __cplusplus */
#endif

I've sent v3 using the second approach above.

Best Regards
 Alistair Leslie-Hughes

[v2 PATCH] include/wincodec.idl: Stop redefinition of ID2D1Image

[Henri Verbeet]

On 16 June 2017 at 11:34, Alistair Leslie-Hughes
 wrote:
> We cannot use "interface ID2D1Image;" like in d2d1.idl.  This is just a forward declare and causes compile errors when building d3dx* with
> ../../include/wincodec.h:5800:9: error: unknown type name ‘ID2D1Image’ ID2D1Image *image

Uhm, no?
> I only see two options,
> - Use the d2d1.idl, which will include extra interfaces not in the original
>
> or
> 2. Add the following to the wincodec.idl.
>
> #ifndef __ID2D1Image_FWD_DEFINED__
> #define __ID2D1Image_FWD_DEFINED__
> typedef interface ID2D1Image ID2D1Image;
> #ifdef __cplusplus
> interface ID2D1Image;
> #endif /* __cplusplus */
> #endif

That's pretty much what "interface ID2D1Image;" does, without the
cpp_quote hackery.