[alsa-devel] usr/include/linux/soundcard.h warnings for 'make headers_check'

[Takashi Iwai]

At Wed, 4 Feb 2009 15:02:07 +0100,
Arnd Bergmann wrote:
> 
> On Wednesday 04 February 2009, Jaswinder Singh Rajput wrote:
> > > +#define _SEQ_EXTERN extern
> > > +#define SEQ_USE_EXTBUF() \
> > > +             _SEQ_EXTERN unsigned char _seqbuf[]; \
> > > +             _SEQ_EXTERN int _seqbuflen;_SEQ_EXTERN int _seqbufptr
> > 
> > hmm, you rename snake as rope, but actually snake is still there ;-)
> 
> Yes, that's true.
> 
> The alternative would be to remove all those macros entirely, breaking
> also the applications from number 2 in my list.
> 
> I see this header as another example of the byteorder.h type where
> a kernel header provides functionality that is used by existing
> applications. While it should have been part of a library to start
> with, we cannot change it any more now without breaking stuff.
> 
> Maybe a comment should be added to clarify this.

Yes, that should help understanding, at least.

I applied your previous patch with this change now no sound git tree,
and will include it in the next pull request.


Thanks!

Takashi

> 
> 	Arnd <><
> 
> --- a/include/linux/soundcard.h
> +++ b/include/linux/soundcard.h
> @@ -1050,7 +1050,17 @@ typedef struct mixer_vol_table {
>   *	Some convenience macros to simplify programming of the
>   *	/dev/sequencer interface
>   *
> - *	These macros define the API which should be used when possible.
> + *	This is a legacy interface for applications written against
> + *	the OSSlib-3.8 style interface. It is no longer possible
> + *	to actually link against OSSlib with this header, but we
> + *	still provide these macros for programs using them.
> + *
> + *	If you want to use OSSlib, it is recommended that you get
> + *	the GPL version of OSS-4.x and build against that version
> + *	of the header.
> + *
> + *	We redefine the extern keyword so that make headers_check
> + *	does not complain about SEQ_USE_EXTBUF.
>   */
>  #define SEQ_DECLAREBUF()		SEQ_USE_EXTBUF()
>  
>