Re: [PATCH][RESEND] do not redefine userspace's NULL #define

From: Peter Seebach
Date: Fri Apr 13 2012 - 18:02:18 EST


On Fri, 13 Apr 2012 12:39:20 -0700
Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> And quite frankly, kernel-external definitions of NULL have
> traditionally been pure sh*t (ie plain "0" without the cast to a
> pointer), so I'm not entirely convinced about this patch.

I was going to dispute this, and point out that I'm pretty sure
the C++ standard specifically requires the plain-integer 0/0L
definition. Then I realized this did not actually contradict
your description.

Maybe the thing to do would be to ensure that NULL goes to __null,
then define that to be ((void *) 0) if the compiler doesn't provide
it? The magic behavior of __null seems like it'd be preferable
where it is available.

-s
--
Listen, get this. Nobody with a good compiler needs to be justified.
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