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Date: Wed, 21 Nov 2001 09:56:15 -0500 (EST)
From: Alexander Viro <viro@math.psu.edu>
To: "Richard B. Johnson" <root@chaos.analogic.com>
cc: Jan Hudec <bulb@ucw.cz>, linux-kernel@vger.kernel.org
Subject: Re: [BUG] Bad #define, nonportable C, missing {}
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On Wed, 21 Nov 2001, Richard B. Johnson wrote:

> On Wed, 21 Nov 2001, Jan Hudec wrote:
> 
> > > >     *a++ = byte_rev[*a]
> > > It looks perferctly okay to me. Anyway, whenever would you listen to a
> > > C++ book talking about good C coding :p
> > 
> 
> It's simple. If any object is modified twice without an intervening
> sequence point, the results are undefined.

That's not all.  There's another case - when modification and use of
the same object happen in undefined order.

And that's precisely what happens here - same as in case of (x + ++x)


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