Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!decwrl!uunet!amgraf!huver
From: huver@amgraf.UUCP (Huver)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Is it me or Manx C 5.0c (the -MR option)
Summary: fabs() vs. FABS()
Message-ID: <414@amgraf.UUCP>
Date: 6 Mar 91 06:25:02 GMT
References: <46418@nigel.ee.udel.edu> <13377@hubcap.clemson.edu>
Organization: Amgraf Inc.,  Kansas City
Lines: 44



cgehman@hubcap.clemson.edu (Corey Gehman) wrote:

>Well, my problem didn't get fixed with the -so option.  Here's the
>smallest I could convert the problem down to:
>
>
>#define FABS(x) ((x) < 0.0 ? (0.0 - (x)) : (x))
>
>double test()
>{
>double i,j;
>
>   return (FABS ( i - j ) + FABS ( i - j ) + FABS ( i - j ));
>}
> ...
>
> I've "fixed" the problem by using a subroutine instead of a macro
> but since I often port software from unix to the amiga I don't want
> to do that everytime.  I don't know if 5.0d version with the -so
> option works or not.

Now I'm not picking on you, but for the particular example, do:

	#include <math.h>

	#define FABS(x) fabs(x)

	/* rest of your code */

and it works just fine; in fact I'd change all FABS() to fabs() calls
and forget about the macro form.  The fabs() is a standard UNIX library
function (System V) which, if you're bringing "software from unix",
should've been used by the original code.  Whatever your UNIX, grep fabs
from <math.h> and see.

The Manx bug is quite interesting though.  With 5.0d/e on your posted code
as is, the -f8 (881 code) option generates absolutely no problem whatsoever,
all other -fX options fail.  Looks like a compiler intended for 020/881 as
a standard platform.  :^)


-huver