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

From: Linus Torvalds
Date: Fri Apr 13 2012 - 15:39:38 EST


On Fri, Apr 13, 2012 at 12:24 PM, Lubos Lunak <l.lunak@xxxxxxx> wrote:
> GCC's NULL is actually __null, which allows detecting some questionable
> NULL usage and warn about it. Moreover each platform/compiler should have
> its own stddef.h anyway (which is different from linux/stddef.h).
> So there's no good reason to override what the compiler provides.
> Keep the #define conditionally, in order to keep the headers self-contained.

There's no way user should ever include the linux internal stddef.h.

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.

So what is the *actual* thing this helps with?

Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/