[PATCH 0/9] uapi: drm: fixes for userspace compilation

[Michel Dänzer]

On 18.11.2015 06:22, Emil Velikov wrote:
> On 17 November 2015 at 19:13, Gabriel Laskar <gabriel at lse.epita.fr> wrote:
>> On Tue, 17 Nov 2015 11:08:12 +0000
>> Emil Velikov <emil.l.velikov at gmail.com> wrote:
>>
>>> With the above said:
>>>  - I was thinking about hiding the UAPI ones, although Dave suggested
>>> against it.
>>>  - Doing s|drm/drm.h|drm.h| will break compilation:
>>>    + for the kernel - as we don't add the foo/drm/ to the include directive,
>>>    + for any hacked up userspace - very unlikely that they have the
>>> include, considering that things work without it.
>>
>> We are not suggesting doing s|drm/drm.h|drm.h| but by replacing
>>
>> #include <drm/drm.h>
>>
>> by
>>
>> #include "drm.h"
>>
>> The header will be picked-up correclty in kernel, and in userland.
>>
> Missed out completely on the <> vs "" side. Imho using the latter the
> kernel will be ok, although for userspace that's not a good idea. What
> will happen if there is a drm.h next to the .c files (I know bad
> programmer) ?

Nothing, at least not with gcc:
https://gcc.gnu.org/onlinedocs/cpp/Search-Path.html

 GCC looks for headers requested with #include "file" first in the
 directory containing the current file, then in the directories as
 specified by -iquote options, then in the same places it would have
 looked for a header requested with angle brackets. For example, if
 /usr/include/sys/stat.h contains #include "types.h", GCC looks for
 types.h first in /usr/include/sys, then in its usual search path.

So #include "drm.h" always picks up drm.h from the same directory where
*_drm.h is.


A for me being confused:

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/include/uapi/drm/amdgpu_drm.h?id=b3fcf36aeef3aeb890d9413c2066048ec7fda7e5

https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/include/uapi/drm/radeon_drm.h?id=e13af53e7d5a8cea8992d9b61fac69bd0ed8d845


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer