Re: [PATCH trivial] UAPI: Kbuild: add/modify comments for"uapi/Kbuild" and "uapi/linux/Kbuild"
From: Geert Uytterhoeven
Date: Wed Sep 04 2013 - 05:27:49 EST
On Wed, Sep 4, 2013 at 11:13 AM, Chen Gang <gang.chen@xxxxxxxxxxx> wrote:
>>> Hmm... why we need "uapi/linux/" ? (I can not find some related
>>> documents, so I have to 'guess').
>>
>> The "uapi" subdirectories are there to distinguish userspace headers from
>> kernelspace headers, and allow both to live in the kernel source tree.
>>
>> When running "make headers_install", the (processed) headers in the
>> various "uapi" subdirectories are copied to /usr/include.
>> Hence "uapi/linux/foo.h" becomes <linux/foo.h> in userspace.
>> In userspace there are no "uapi" subdirectories anymore.
>>
>
> Yeah, so why need another "uapi/*" excluding "uapi/linux" ?
>
> Are they also truly still "Userspace API" but which need not distinguish
> ? (at least, it seems that idea is not quite good).
>
> Hmm... maybe the "uapi/*" except "uapi/linux" are also installed? Is it
> for compatible (originally they are here, and now we have to follow, it
> is no reason to change if not find related critical issues)?
All uapi files are installed, a.o. /usr/include/scsi/, /usr/include/video/, ...
Historically, everything under "include" in the kernel source tree was
installed in /usr/include/, after (semi)manual cleanup.
Since the uapi split, everything is handled automatically.
Because of compatibility reasons (do not break userspace), paths had to
stay the same.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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