On Mon, 07 Dec 2020 10:53:49 +0000
Simon Ser <contact@emersion.fr> wrote:

> On Monday, December 7th, 2020 at 11:49 AM, James Park <james.park@lagfreegames.com> wrote:
> 
> > That would work, but that's kind of an annoying requirement. I would
> > prefer the header to be self-sufficient.  
> 
> I don't want to make it more confusing than before, but here Pekka (I
> think) suggests to replace this:
> 
> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
> index 82f3278..5eb07a5 100644
> --- a/include/uapi/drm/drm_fourcc.h
> +++ b/include/uapi/drm/drm_fourcc.h
> @@ -24,7 +24,11 @@
>  #ifndef DRM_FOURCC_H
>  #define DRM_FOURCC_H
> 
> +#ifdef DRM_FOURCC_STANDALONE
> +#include "drm_basic_types.h"
> +#else
>  #include "drm.h"
> +#endif
> 
>  #if defined(__cplusplus)
>  extern "C" {
> 
> With this:
> 
> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
> index 82f3278..5eb07a5 100644
> --- a/include/uapi/drm/drm_fourcc.h
> +++ b/include/uapi/drm/drm_fourcc.h
> @@ -24,7 +24,11 @@
>  #ifndef DRM_FOURCC_H
>  #define DRM_FOURCC_H
> 
> +#include "drm_basic_types.h"
> +
> +#ifndef DRM_FOURCC_STANDALONE
>  #include "drm.h"
> +#endif
> 
>  #if defined(__cplusplus)
>  extern "C" {
> 
> That wouldn't change whether the header is self-sufficient or not,
> would it?

Exactly this.

This communicates properly that DRM_FOURCC_STANDALONE only affects
whether drm.h gets pulled in or not, and there are no other effects.

This also makes testing better: when you unconditionally include
drm_basic_types.h, you are more likely to catch breakage there.

For functionality, it makes no difference. Whether userspace does

#include "drm.h"
#define DRM_FOURCC_STANDALONE
#include "drm_fourcc.h"

or

#define DRM_FOURCC_STANDALONE
#include "drm_fourcc.h"
#include "drm.h"

the result must always be good.


Thanks,
pq