Date: Mon, 31 Dec 2001 16:52:33 -0800 From: Marcel Moolenaar <marcel@xcllnt.net> To: Julian Elischer <julian@elischer.org> Cc: John Baldwin <jhb@FreeBSD.org>, Poul-Henning Kamp <phk@critter.freebsd.dk>, cvs-all@FreeBSD.org, cvs-committers@FreeBSD.org, Julian Elischer <julian@FreeBSD.org>, Greg Lehey <grog@FreeBSD.org> Subject: Re: cvs commit: src/share/man/man3 queue.3 Message-ID: <20011231165233.A408@dhcp01.pn.xcllnt.net> In-Reply-To: <Pine.BSF.4.21.0112311328270.94344-100000@InterJet.elischer.org> References: <XFMail.011231123912.jhb@FreeBSD.org> <Pine.BSF.4.21.0112311328270.94344-100000@InterJet.elischer.org>
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On Mon, Dec 31, 2001 at 01:38:53PM -0800, Julian Elischer wrote:
> > >
> > > _FOREACH() is for the plain & simple traversal of a queue(3) stucture,
> > > anything more should explicitly state intent.
> >
> > I would agree except for code like this:
> >
> > TAILQ_FOREACH(p, &list, p_next)
> > if (some_test_on(p))
> > break;
> > if (p != NULL) {
> > /* Found one, now do something. */
> > }
>
> This is the case I'm using it for.
> except I'm doing:
> TAILQ_FOREACH(p, &list, p_next)
> if (some_test_on(p))
> break;
> if (p != NULL) {
> /* Found it, now do something. */
> }
> lots of code that MAY clear p
> if (p == NULL) {
> /* didn't find it, or it was disqualified */
> }
I'd consider this a misuse of _FOREACH, because the something that's
being done is definitely not done for each p. Even some_test_on() is
not performed on each p. I'm with phk here.
Note that if it's simply too easy to use _FOREACH in these cases, we
may want to consider creating a more suitable abstraction, like:
TAILQ_UNTIL(p, &list, p_next)
some_test_on(p);
if (p == 0)
return ENOTFOUND;
/* do something */
return 0;
Just a thought.
--
Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net
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