Re: [PATCH 16/16] fix handling of integer constant expressions

From: Al Viro
Date: Sun Jun 24 2007 - 15:10:27 EST


On Sun, Jun 24, 2007 at 08:07:10PM +0200, Arnd Bergmann wrote:
> One minor issue though:
> While BUILD_BUG_ON and a few other macros in linux/kernel.h are currently
> exported to user space, I would think that they should really be hidden
> in #ifdef __KERNEL__, which means that we also need something like
>
> #ifdef __KERNEL__
> #define _IOC_TYPECHECK(t) \
> (sizeof(t) + BUILD_BUG_ON_ZERO(sizeof(t) == sizeof(t[1]) && \
> sizeof(t) < (1 << _IOC_SIZEBITS)))
> #else
> #define _IOC_TYPECHECK(t) sizeof(t)
> #endif

Point, but then we might want to export the damn thing in properly
named version (i.e. put it into __.... reserved namespace). It
doesn't depend on anything kernel-specific...

FWIW, the current version suffers from similar problem - it's outside
of __KERNEL__ in userland-exported header and it can lead to breakage
when included in build by something other than gcc...
-
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/