Path: utzoo!attcan!uunet!mcsun!ukc!pyrltd!tetrauk!rick
From: rick@.tetrauk.UUCP (Rick Jones)
Newsgroups: comp.lang.c
Subject: Re: IsUnsigned() function (retiring injured)
Message-ID: <621@.tetrauk.UUCP>
Date: 30 Jul 90 09:46:32 GMT
References: <1990Jul27.161339.14712@kfw.COM> <8118@ncar.ucar.edu>
Reply-To: rick@tetrauk.UUCP (Rick Jones)
Organization: Tetra Ltd., Maidenhead, UK
Lines: 13

I knew I should have kept out of this!

My suggestion [#define IsUnsigned(a) (a >= 0 && ~a > 0)] will spot a compiler
with wrong promotion of short types, but I have to admit the macro fails with
ANSII promotion, while working with old K&R.  Comes of using pretend ANSII
compilers, I suppose, and K&R version 2 is _horribly_ ambiguous about "~".

Perhaps I finally understand the ANSII promotion rules at last!

-- 
Rick Jones					You gotta stand for something
Tetra Ltd.  Maidenhead, Berks			Or you'll fall for anything
rick@tetrauk.uucp (...!ukc!tetrauk.uucp!rick)	     - John Cougar Mellencamp