Date: Tue, 2 Mar 2004 17:14:18 +1100 (EST) From: Bruce Evans <bde@zeta.org.au> To: Stefan Farfeleder <stefan@fafoe.narf.at> Cc: current@freebsd.org Subject: Re: NULL vs 0 vs 0L bikeshed time Message-ID: <20040302164649.K8656@gamplex.bde.org> In-Reply-To: <20040301224712.GB959@wombat.fafoe.narf.at> References: <20040301213454.GA959@wombat.fafoe.narf.at> <200403012158.i21LwS0w084961@grimreaper.grondar.org> <20040301224712.GB959@wombat.fafoe.narf.at>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, 1 Mar 2004, Stefan Farfeleder wrote:
> On Mon, Mar 01, 2004 at 09:58:28PM +0000, Mark Murray wrote:
> > Stefan Farfeleder writes:
> > > On Sun, Feb 29, 2004 at 03:46:35PM +0000, Mark Murray wrote:
> > >
> > > > -#define NULL 0L
> > > > +#define NULL (0L)
> > >
> > > What's the point of parenthesizing 0L?
> >
> > Its two lexical elements. I got into the habit of doing that when a
> > macro replacement bit me some years ago. It is a very unimportant part
> > of the patch. :-)
>
> While I agree that it's quite unimportant, I have to contradict you.
> `OL' is a pp-number which is converted to an integer-constant in
> translation phase 7 according to the C standard. It always is a single
> token.
Understanding pp-numbers and transaltion phases is unecessary for this.
Quoting small parts of section 6.4:
token:
...
constant
...
constant:
integer-constant
...
integer-constant:
decimal-constant integer-suffix-opt
...
So the suffix is part of the token for integer constants.
pp-numbers and translation phases, whatever they are, must be consistent
with this. For tokens, I think this just means that every C token is a
pp-token.
Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20040302164649.K8656>