From: Damian Yerrick <Bullcr_pd_yerrick AT hotmail DOT comRemoveBullcr_p>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Weird results of log( -1.0 ) with libm.a and without libm.a
Organization: Pin Eight Software  http://pineight.8m.com/
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NNTP-Posting-Date: Wed, 17 Jan 2001 03:35:25 GMT
Distribution: world
Date: Wed, 17 Jan 2001 03:35:25 GMT
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp
Reply-To: djgpp AT delorie DOT com

On Mon, 15 Jan 2001 10:00:49 +0700, "Tanes Sriviroolchai"
<Tanes DOT Sriviroolchai AT Thailand DOT NCR DOT COM> wrote:

>"Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il> wrote in message
>news:6480-Fri12Jan2001134540+0200-eliz AT is DOT elta DOT co DOT il...
>>
>> You should be able to look at the bit pattern of the result and
>> compare it with NaN and Inf, if you don't believe isnan.
>
>No, I'm ok with all behavior of log() and isnan() in DJGPP. The only
>(small) problem is isnan() is not available in libc.a.

Get the libm sources (djlsr203.zip from Simtel) and pull out isnan()
if you feel that strongly.

>However, I can compare the result directly with NaN and Inf

You can't just do if(x == 0./0.) because there are several types
of NaN; each has a different non-zero characteristic.  +Inf can
be considered a NaN with a characteristic of all zero bits.

-- 
<O
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