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From: John Baldwin <jhb@freebsd.org>
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Date: Thu, 15 Apr 2010 10:14:17 -0400
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Cc: Lawrence Stewart <lstewart@freebsd.org>, tuexen@freebsd.org,
	rrs@freebsd.org
Subject: Re: A cookie for anyone who can solve this C/macro problem...
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On Thursday 15 April 2010 9:17:14 am Lawrence Stewart wrote:
> void
> newreno_ack_received(struct cc_var *ccv)
> {
> 	u_int cw = CCV_DO(ccv, snd_cwnd);
> 	...
> 	CCVC(ccv, snd_cwnd = blah);
> }
> 
> Of course, this falls apart if you try do this for example:
> 
> 	CCVC(ccv, snd_cwnd = min(blah, bleh));
> 
> 
> So... I'm sure there are some good ideas out there and would really 
> appreciate hearing about them.

If you want to go this route, you could use separate _SET and _GET macros ala 
PCPU_*().  Then you would end up with something like:

	u_int cw = CCV_GET(ccv, snd_cwnd);

	CCV_SET(ccv, snd_cwnd, min(blah, bleh));


-- 
John Baldwin