From owner-freebsd-hackers  Fri Jul  6  7:35:57 2001
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Date: Fri, 6 Jul 2001 17:40:19 +0300
From: Peter Pentchev <roam@orbitel.bg>
To: Evan Sarmiento <kaworu@sektor7.ath.cx>
Cc: freebsd-hackers@freebsd.org
Subject: Re: LIST_NEXT()
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In-Reply-To: <200107061348.JAA26189@mail1.javanet.com>; from kaworu@sektor7.ath.cx on Fri, Jul 06, 2001 at 09:48:26AM -0400
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On Fri, Jul 06, 2001 at 09:48:26AM -0400, Evan Sarmiento wrote:
> Hello,
> 
> I'm writing a kernel module, and it involves traversing the proc list searching for the right structure,
> however, when I use SLIST_NEXT(p, p_list) in the program, I get a warning when I compile it: 
> 
> warning: statement with mo effect
> 
> What am I doing wrong? I've read the manpages on queue and looked at the proc structure.
> 
> Here's the code:
> int
> prfw_setflags(p, uap)
> struct proc *p;
> struct prfw_setflags_args *uap;
> {
> ...
> if (uap->id) {
>  while (uap->id != p->p_pid)
>   LIST_NEXT(p, p_list);
> }

Well, first, you're using LIST_NEXT(), not SLIST_NEXT() :)
Second, none of the *_NEXT() queue.h macros modify their parameters;
they just return a pointer to the next element.  So, just try:

	p = LIST_NEXT(p, p_list);

..and you'll be just fine.

G'luck,
Peter

-- 
If I were you, who would be reading this sentence?

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