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From: gnu@l5.uucp (John Gilmore)
Newsgroups: net.lang.c
Subject: Re: /-INFINITY and NaN
Message-ID: <360@l5.uucp>
Date: Thu, 26-Dec-85 20:16:26 EST
Article-I.D.: l5.360
Posted: Thu Dec 26 20:16:26 1985
Date-Received: Sat, 28-Dec-85 01:31:42 EST
References: <978@brl-tgr.ARPA>
Organization: Nebula Consultants in San Francisco
Lines: 7

Sun Unix uses IEEE float.  They provide library routines isnan() and isinf().
Note that there are two infinite values (positive and negative) and many
NaNs, so a simple compare to a single value is not good enough.

These library routines seem to be a good idea, since they can be implemented
for all kinds of float (eg, Vax, IBM) and increase portability.  (A system
without infinites or NaNs would always return false of course.)