On Mon, Dec 15, 2014 at 11:44:21AM +0000, One Thousand Gnomes wrote:
> On Sat, 13 Dec 2014 11:46:47 -0800
> Jeremiah Mahler <jmmahler@xxxxxxxxx> wrote:
>
> > Loïc,
> >
> > On Sat, Dec 13, 2014 at 07:22:38PM +0100, Loic Pefferkorn wrote:
> > > > Whose convention is this? I can't find any mention in
> > > > Documention/CodingStyle. checkpatch.pl doesn't complain about them.
> > > > And there are almost three thousand examples in staging which don't
> > > > use this convention.
> > > >
> > > > linux-next$ grep -r "== NULL" drivers/staging/* | wc -l
> > > > 2844
> > >
> > > Hi Jeremiah,
> > >
> > > Thanks for your feedback.
> > >
> > > I have used checkpatch.pl with the --strict flag:
>
> checkpatch.pl is a bit dubious at the best of times - you can't automate
> taste without an AI ;). With --strict it's a positive hazard.
>
> Those kind of small cleanups really only make sense if you are doing big
> changes to the code itself anyway and are doing testing and all the rest.
>
> In this case I'd say checkpatch.pl is actually wrong because in the
> general case it's better to compare with NULL in C
>
> If you write
>
> if (!x)
>
> and accidentally use a non-pointer type you don't get a warning. If you
> try and compare a non pointer type to NULL you usually do. So the NULL
> comparison avoids accidents.
>
> The historical reason for it being done in C was I think to avoid the
>
> if (x = NULL)
>
> bug, but gcc will shout at you for that these days.
>
Or another way mentioned in K&R that produces a compile error
if (NULL = x)
> Alan
>
>
>
--
- Jeremiah Mahler
_______________________________________________
devel mailing list
devel@xxxxxxxxxxxxxxxxxxxxxx
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
