Date: Thu, 03 Jan 2002 00:40:54 +1000 From: Stephen McKay <mckay@thehub.com.au> 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>, mckay@thehub.com.au Subject: Re: cvs commit: src/share/man/man3 queue.3 Message-ID: <200201021440.g02Eess11512@dungeon.home> In-Reply-To: <Pine.BSF.4.21.0112311706450.10883-100000@InterJet.elischer.org> from Julian Elischer at "Tue, 01 Jan 2002 01:14:08 %2B0000" References: <20011231165233.A408@dhcp01.pn.xcllnt.net> <Pine.BSF.4.21.0112311706450.10883-100000@InterJet.elischer.org>
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On Tuesday, 1st January 2002, Julian Elischer wrote:
>> > TAILQ_FOREACH(p, &list, p_next)
>
>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?
I'd have to say, "Yes". I expect p to be undefined when the TAILQ_FOREACH
completes. It's an internal implementation detail. Similarly, I wouldn't
depend on p == head for CIRCLEQ_FOREACH. You can roll your own loop if
you want special behaviour.
>I'm just documenting what the code does, and how people have used it.
>if you think that phk is correct we should add an example to the man page
>showing:
Perhaps Marcel's good example instead:
> TAILQ_FOREACH(p, &list, p_next) {
> if (some_test_on(p)) {
> /* Do something */
> break; /* optional */
> }
> }
The man page should explicitly state that p is undefined after the loop
completes unless the user breaks out. Oh, and explicitly stating that it
is OK to break out at all might be nice too. :-)
Stephen.
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