Article View: comp.sys.next.programmer
Article #1876Re: trapping NaN
From: Ralph Zazula
Date: Sat, 21 Nov 1992 18:13
Date: Sat, 21 Nov 1992 18:13
31 lines
1244 bytes
1244 bytes
In article <1992Nov20.221038.1170@proforma.com> writes:
> I would like to trap NaN -- the "not a number" condition that floating point
> values can take. I can't find any clue on how to do this, except some
cryptic
> stuff in the man pages under "math". Is there some signal I can handle?
>
> Thanks in advance.
> --J Gregory
Hi -
It turns out that (NaN != NaN) is true. So, in some code I did before, I used:
if(x == x) { /* x is NOT NaN */
< use x>
}
else {
<whatever for the NaN case>
}
Here's the excerpt from the manual page:
"If x != x then x is NaN; every other predicate (x > y, x = y, x < y,...) is
FALSE if NaN is involved."
Ralph
---
Ralph Zazula
Pinnacle Research, Inc.
zazula@pri.com (NeXT Mail)
(602)529-1135
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Path: arc1-ca.pugleaf.net!sparky!uunet!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!att!news.cs.indiana.edu!arizona.edu!arizona.edu!news Newsgroups: comp.sys.next.programmer Subject: Re: trapping NaN Message-ID: <1992Nov21.111335.4014@arizona.edu> From: zazula@pri.com (Ralph Zazula) Date: 21 Nov 92 11:13:35 MST Reply-To: zazula@pri.com References: <1992Nov20.221038.1170@proforma.com> Distribution: world,local Nntp-Posting-Host: bonehead.tucson.az.us Lines: 31