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Date: Tue, 24 Feb 2004 10:39:28 -0500
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From: DJ Delorie <dj AT delorie DOT com>
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	Hans-Bernhard Broeker on 24 Feb 2004 13:12:22 GMT)
Subject: Re: Fibonacci number
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> Since negation is a well-defined operation on unsigned longs, there's
> no error involved.

This makes no sense.  *All* arithmetic operations are well defined for
all integer types, but still, POSIX requires a range error.  IMHO this
means we're meant to check the range of the number *before* folding it
to the target type.