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Article #4524Re: Microsoft C actually does something better!
From: Duncan Murdoch
Date: Tue, 05 Feb 1991 02:04
Date: Tue, 05 Feb 1991 02:04
32 lines
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1751 bytes
In article <8904@sail.LABS.TEK.COM> toma@sail.LABS.TEK.COM (Tom Almy) writes:
>Microsoft C has been bad-mouthed here by myself and others over the years,
>but this past weekend I discovered at least one place where it beats the
>major competition -- the math library. Two cases:
>
>Case 1: { double x=1e200; printf("%g",x*x); }
>(With some compilers, the 80x87 has to have the overflow trap masked off).
I tried your tests in Turbo Pascal 6.0, and was pleasantly surprised at the
results. (TP 6.0 has some real problems with esoteric floating point code.)
>
>Microsoft C (V6.00A): prints +inf (correct!)
MSC may be correct for C, but TP prints 1.00000000E+0400, which is even more
correct. (This is because TP promotes expressions to the 10 byte extended
type.) When I forced the result to go into a double, I got an overflow
error; when I masked those, I got INF.
>
>Case 2: { double x=1e50; x = sin(x); printf("%g", x);}
>( matherr() function defined where available )
>
>Microsoft: sine function causes error "Total loss of significance" (correct!)
TP just gives an invalid operation error, or a NAN when masked.
>A test of some other language compilers produced dismal results as well.
>Only Microsoft C worked.
And TP!
Duncan Murdoch
dmurdoch@watstat.waterloo.edu
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Newsgroups: comp.os.msdos.programmer Path: arc1-ca.pugleaf.net!utzoo!utgpu!watserv1!maytag!watstat.waterloo.edu!dmurdoch From: dmurdoch@watstat.waterloo.edu (Duncan Murdoch) Subject: Re: Microsoft C actually does something better! Message-ID: <1991Feb5.020455.26710@maytag.waterloo.edu> Sender: daemon@maytag.waterloo.edu (Admin) Organization: University of Waterloo References: <8904@sail.LABS.TEK.COM> Date: Tue, 5 Feb 91 02:04:55 GMT Lines: 32