[lkml]   [2003]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH] 2.4.22pre10: {,un}likely_p() macros for pointers
Alan Cox wrote:
> > I believe the C language allows for systems where the NULL pointer is
> > not zero.

The representation is not zero, however in the C language (since ANSI,
not sure about K&R), 0 is a valid name for the NULL pointer whatever
its representation.

> > I can't think of any reason why the NULL macro exists otherwise.
> <OldFart>
> NULL is really important in K&R C because you don't have prototypes and
> sizeof(foo *) may not be the same as sizeof(int). This leads to very
> nasty problems that people nowdays forget about.
> </OldFart>

Not just K&R. These are different because of varargs:

printf ("%p", NULL);
printf ("%p", 0);

-- Jamie
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:47    [W:0.096 / U:1.064 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site