Date: Wed, 1 Jun 2005 08:06:41 -0700 From: Luigi Rizzo <rizzo@icir.org> To: freebsd-arch@freebsd.org, delphij@delphij.net Subject: Re: [PATCH RFC] Add a macro for null mount options to sbin/mount* Message-ID: <20050601080641.H30391@xorpc.icir.org> In-Reply-To: <20050601150344.GA39784@dragon.NUXI.org>; from obrien@freebsd.org on Wed, Jun 01, 2005 at 08:03:44AM -0700 References: <1117613456.771.16.camel@spirit> <20050601150344.GA39784@dragon.NUXI.org>
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On Wed, Jun 01, 2005 at 08:03:44AM -0700, David O'Brien wrote:
> On Wed, Jun 01, 2005 at 04:10:56PM +0800, Xin LI wrote:
> > Hi, -arch@,
> >
> > In our mount* utilities, the null mount option, which is usually be used
> > as a terminator of an option vector, is defined with some hand-rolled
> > terms, e.g.: {NULL}, {NULL, 0, 0, 0}, etc.
> >
> > I think it would be nice to have a new macro to deal with this, say,
> > MOPT_NULL, which would be extended to {NULL, 0, 0, 0}, which can act as
> > an explicit initialize. And in my opinion, something like:
>
> I think it is better to leave it alone. The "NULL" termination of a list
> like this is a C idiom that should be clear to any C programmer. Hiding
> the details in a macro (is MOPT_NULL an integer or a sentinel?) makes it
> harder to see the idiom and know exactly what is going on and how this
> list will be processed.
on one side I have to agree here... however the alternative terms
might cause problems with stricter compile flags (e.g. when some
of the forms do not supply all fields), so perhaps a decent compromise
could be to find a more explicative name such as MOPT_END or the like.
cheers
luigi
> --
> -- David (obrien@FreeBSD.org)
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