Re: bitops.h ifdef __KERNEL__ cleanup.

H. Peter Anvin (hpa@zytor.com)
19 Jul 2001 21:18:41 -0700


Followup to: <11472.995579612@redhat.com>
By author: David Woodhouse <dwmw2@infradead.org>
In newsgroup: linux.dev.kernel
>
> It has been stated many times that kernel headers should not be used in
> apps. Renaming or moving them should not be necessary - and people would
> probably only start to use them again anyway. We'd see autoconf checks to
> find whether it's linux/private.h or xunil/private.h :)
>
> In the absence of any expectation that userspace developers will ever obey
> the simple and oft-repeated rule that you don't use kernel headers from
> userspace, the #ifdef __KERNEL__ approach would seem to be the best on
> offer.
>

Note that the rule is at least in part theoretical; even glibc include
kernel headers or -derivatives.

I think the idea with <asm/bitops.h> is that they are protected by
#ifdef __KERNEL__ if they are kernel-only; however, if they work in
user space then there is no #ifdef and autoconf can detect their
presence.

-hpa

-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt
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