Re: DVB Include files

Marcus Metzler (mocm@metzlerbros.de)
Wed, 25 Jun 2003 20:43:23 +0200 (CEST)


Christoph Hellwig writes:
> On Wed, Jun 25, 2003 at 08:09:51PM +0200, Marcus Metzler wrote:
> > > If the structures change incompatibly you're fucked anyway. Better
> >
> > Not necessarily, e.g. changing
> >
> > #define AUDIO_SET_ATTRIBUTES _IOW('o', 17, audio_attributes_t)
> > #define AUDIO_SET_KARAOKE _IOW('o', 18, audio_karaoke_t)
> >
> > to
> >
> > #define AUDIO_SET_ATTRIBUTES _IOW('o', 47, audio_attributes_t)
> > #define AUDIO_SET_KARAOKE _IOW('o', 48, audio_karaoke_t)
> >
> > or
>
> In that case yes, you are screwed. Your ABI just changed incompatibly.

Not if you recompile.

>
> > Anyway, even in user/include it should be under linux/dvb because
> > that's just what it is Linux DVB. So the app has to include
> > <linux/dvb/xxx.h>.
>
> No! <linux/*.h> is the namesapce for kernelheaders. Currently they're
> still in the the user includes, too (due to legacy reasons). The
> DVD API must move to a directory outside <linux/dvb>.
>

Why (It's DVB by the way)? It's as close to the kernel as ls or cat
and having two sets of the same includes is stupid.

> If you userland packages add headers to /usr/include/linux/ they
> are totally bogus.
>

What packages? You are always talking about packages. There are no packages.
There are only the kernel and my app. Nothing else. No copying of headers.

> > I don't care what distributions do. When I get a new kernel (no
> > packages), I use the includes from that kernel and compile my apps
> > with that.
>
> And that's wrong. You must always compile against the kernel headers
> that your libc was compiled against.
>

There is no one who does that, not even distributions. The includes
needed for libc are far less prone to change than v4l or dvb. And not
as linux specific.

I see your point, but right now it's only academic and not practicable.

Marcus

-- 
/--------------------------------------------------------------------\
| Dr. Marcus O.C. Metzler        |                                   |
|--------------------------------|-----------------------------------|
| mocm@metzlerbros.de            | http://www.metzlerbros.de/        |
\--------------------------------------------------------------------/

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