Date: Mon, 31 Dec 2001 19:01:26 -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: <20011231190126.A755@dhcp01.pn.xcllnt.net> In-Reply-To: <Pine.BSF.4.21.0112311706450.10883-100000@InterJet.elischer.org> References: <20011231165233.A408@dhcp01.pn.xcllnt.net> <Pine.BSF.4.21.0112311706450.10883-100000@InterJet.elischer.org>
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On Mon, Dec 31, 2001 at 05:14:08PM -0800, Julian Elischer wrote:
>
> > 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.
>
> So you think that the final value of p should be undefined,
> and there is no built in way to see if there were any elements in the
> list at all or whether we completed the list?
Theoretically speaking, yes.
> I'm just documenting what the code does, and how people have used it.
I understand that and didn't really object to that.
> if you think that phk is correct we should add an example to the man page
> showing:
>
>
> TAILQ_FOREACH(p, &list, p_next)
> if (some_test_on(p))
> goto fred;
> goto jim;
> fred: print ("we got one");
> jim:
What's wrong with the following if _FOREACH is preferred:
TAILQ_FOREACH(p, &list, p_next) {
if (some_test_on(p)) {
/* Do something */
break; /* optional */
}
}
--
Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net
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