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From: flint@gistdev.UUCP
Newsgroups: comp.unix.wizards
Subject: Re: what does NaN mean out of printf?
Message-ID: <8800025@gistdev>
Date: 19 Jul 89 18:02:00 GMT
References: <20283@adm.BRL.MIL>
Lines: 11
Nf-ID: #R:adm.BRL.MIL:20283:gistdev:8800025:000:571
Nf-From: gistdev.UUCP!flint    Jul 19 13:02:00 1989


NaN is not a number.  An easy way to get that is having a union, or by
doing a cast (of a long to a float) when you shouldn't.  For example, the
bit pattern for the integer -1L (all bits set) does not correspond to any
legal floating point value.  SYS V has an isnan(3C) function to test if a
value is legal floating point without generating an exeception. 

Flint Pellett, Global Information Systems Technology, Inc.
1800 Woodfield Drive, Savoy, IL  61874     (217) 352-1165
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