linux-kernel - Re: Conversion to generic boolean

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Date:	Mon, 28 Aug 2006 12:15:40 -0700
From:	Nicholas Miell <nmiell@...cast.net>
To:	Richard Knutsson <ricknu-0@...dent.ltu.se>
Cc:	Jan Engelhardt <jengelh@...ux01.gwdg.de>,
	Christoph Hellwig <hch@...radead.org>,
	James.Bottomley@...elEye.com, linux-scsi@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: Conversion to generic boolean

On Mon, 2006-08-28 at 14:17 +0200, Richard Knutsson wrote:
> Jan Engelhardt wrote:
> 
> >>>Just would like to ask if you want patches for:
> >>>      
> >>>
> >>Total NACK to any of this boolean ididocy.  I very much hope you didn't
> >>get the impression you actually have a chance to get this merged.
> >>
> >>    
> >>
> >>>* (Most importent, may introduce bugs if left alone)
> >>>Fixing boolean checking, ex:
> >>>if (bool == FALSE)
> >>>to
> >>>if (!bool)
> >>>      
> >>>
> >>this one of course makes sense, but please do it without introducing
> >>any boolean type.  Getting rid of all the TRUE/FALSE defines and converting
> >>all scsi drivers to classic C integer as boolean semantics would be
> >>very welcome janitorial work.
> >>    
> >>
> >
> >I don't get it. You object to the 'idiocy' 
> >(http://lkml.org/lkml/2006/7/27/281), but find the x==FALSE -> !x 
> >a good thing?
> >  
> >
> That is error-prone. Not "==FALSE" but what happens if x is (for some 
> reason) not 1 and then "if (x==TRUE)".

If you're using _Bool, that isn't possible. (Except at the boundaries
where you have to validate untrusted data -- and the compiler makes that
more difficult, because it "knows" that a _Bool can only be 0 or 1 and
therefore your check to see if it's not 0 or 1 can "safely" be
eliminated.)

-- 
Nicholas Miell <nmiell@...cast.net>

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