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Re: comparisons..

To: toon at moene dot indiv dot nluug dot nl
Subject: Re: comparisons..
From: "Martin v. Loewis" <martin at loewis dot home dot cs dot tu-berlin dot de>
Date: Fri, 14 Jul 2000 22:58:21 +0200
CC: andrewm at uow dot edu dot au, pfeifer at dbai dot tuwien dot ac dot at, meissner at cygnus dot com, gcc at gcc dot gnu dot org
References: <396D78FE.C4A91B53@uow.edu.au> <Pine.BSF.4.21.0007131840510.71820-100000@taygeta.dbai.tuwien.ac.at> <396E5ABD.856EACF4@uow.edu.au> <396EF633.A6FB44AB@moene.indiv.nluug.nl>

> I always wondered whether it would be possible to drop the warning in
> case the signed constant has the same value when interpreted as an
> unsigned value.  Obviously, it is useful to compare an unsigned variable
> against a _positive_ constant, even if it - strictly according to the
> rules - should be interpreted as a signed quantity.  Or is this a
> promotion-hair issue ?

The warning is not justified in this case. The integer constant is
converted into an unsigned integer, and standard C guarantees that
there will be no change in value due to this conversion. So writing

  x > 5

is guaranteed to be the same thing as

  x > 5U

Regards,
Martin

References:
- Re: comparisons..
  - From: Andrew Morton
- Re: comparisons..
  - From: Gerald Pfeifer
- Re: comparisons..
  - From: Andrew Morton
- Re: comparisons..
  - From: Toon Moene

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