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From: karl@haddock.ima.isc.com (Karl Heuer)
Newsgroups: comp.lang.c
Subject: Re: Help with function
Message-ID: <15697@haddock.ima.isc.com>
Date: 19 Jan 90 20:17:50 GMT
References: <2385@ektools.UUCP> <3477@cbnewsj.ATT.COM>
Reply-To: karl@haddock.ima.isc.com (Karl Heuer)
Distribution: na
Organization: Interactive Systems, Cambridge, MA 02138-5302
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In article <3477@cbnewsj.ATT.COM> veenu@cbnewsj.ATT.COM (veenu.r.rashid,mt,) writes:
>As it turns out, the abs() macro definition tends to return int, (but not
>always!), while fabs() returns the correct floating point value.  Now, is
>this just a macro characteristic or is it the compiler I'm using.

|abs| is a standard library function that expects an |int| and returns an
|int|.  I don't know anything about the macro definition on your machine, and
neither should you, if you're interested in writing portable programs.
Passing it a non-|int| value is undefined behavior; all bets are off.

Karl W. Z. Heuer (karl@haddock.isc.com or ima!haddock!karl), The Walking Lint
________
I'm assuming you have a sane implementation.  If |abs| is defined as
	#define abs(x) ((x) < 0 ? -(x) : (x))
then you should file a bug report, since it will break code like |abs(*p++)|.