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Re: always true warning

From: Hallvard B Furuseth
Subject: Re: always true warning
Date: Sat, 23 Dec 2006 14:04:14 +0100 writes:

> What I did is I implemented template fn bool isnegative() which is used
> instead of <0.
> This fn returns false in general and is specialized for signed types so
> that it returns <0.

In GNU C I'd use

#define isnegative(i) \
  ((__typeof__(i))-1 < 1 && (i) < (__typeof__(i)) ((__typeof__(i))-1 > 0))

For unsigned types it becomes (false && ...skipped...)
For signed types, (true && (i) < (__typeof__(i))false).
Possibly the (__typeof(i)__) cast can be skipped without provoking any
warnings, I'm not sure.

Maybe there is a C++ way to do something similar, without using a Gnu


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