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From: Richard Knutsson <ricknu-0@student.ltu.se>
To: kernel-janitors@vger.kernel.org
Subject: Re: [KJ] [RFC] Regarding abs() and labs()
Date: Sat, 03 Feb 2007 02:22:29 +0000	[thread overview]
Message-ID: <45C3F1E5.8020600@student.ltu.se> (raw)
In-Reply-To: <45C3E1C8.2040105@student.ltu.se>

Randy Dunlap wrote:
> On Sat, 03 Feb 2007 02:13:44 +0100 Richard Knutsson wrote:
>
>   
>> Hello all
>>
>> Just took a look at abs() and can not understand why it seem so 
>> overcomplicated. Why not just:
>>
>> #define abs(x)	((x) < 0) ? -(x) : (x))
>>     
>
> It's almost that simple.  It just adds a local __x so that
> 'x' won't be evaluated multiple times as it would in the simpler
> version.  Multiple evaluations (of an expression) (that could
> have side effects) would take more CPU horsepower and could
> have bad side effects as well.
>   
You mean if x is ex a + b? In such case; why not use typeof instead of int?
What kind of side-effects are you talking about?

Richard Knutsson

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  parent reply	other threads:[~2007-02-03  2:22 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-03  1:13 [KJ] [RFC] Regarding abs() and labs() Richard Knutsson
2007-02-03  1:44 ` Randy Dunlap
2007-02-03  2:22 ` Richard Knutsson [this message]
2007-02-03  2:34 ` Randy Dunlap
2007-02-03  2:52 ` Richard Knutsson

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