From -6892430913922416890 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,d93488bb970aa444 X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2001-06-13 07:33:00 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!dispose.news.demon.net!news.demon.co.uk!demon!mail2news.demon.co.uk!not-for-mail From: "Greg Brewer" Newsgroups: comp.std.c++ Subject: Re: How to test for NaNs and infinites? Date: Wed, 13 Jun 2001 14:32:47 GMT Organization: Houston Area League of PC Users Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: <9g7si3$1n7n$1@news.hal-pc.org> References: <3B176D2F.70C3E7F7@meteo.fr> <9fql8h$pfg$1@news.hal-pc.org> <3B21100E.5B25F7AA@acm.org> <9frdlp$14bc$1@news.hal-pc.org> <9g2em7$1pkk$1@news.hal-pc.org> X-Trace: mail2news.demon.co.uk 992442771 mail2news:21177 mail2news mail2news.demon.co.uk X-Complaints-To: abuse@demon.net X-Mail2News-Path: news.demon.net!mulga.cs.mu.oz.au X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) NNTP-Posting-Date: Wed, 13 Jun 2001 14:15:31 +0000 (UTC) X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.00.3018.1300 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.3018.1300 Lines: 35 Xref: archiver1.google.com comp.std.c++:6053 James Kuyper Jr." wrote in message news:3B25A13B.4EFB1085@wizard.net... > The first web site my search engine found describing IEEE formats was: > > I hope that's acceptable. I got my info from http://octarine.itsc.adfa.edu.au:8080/workshopdocs/common/ug/ncg_math.doc.ht ml I don't want to get into some complicated argument as to whether or not infinity (plus or minus) is a number; I don't consider it one. I consider infinity 2 special cases of not a number and therefor one is a subset of the other. I suppose I could just call the function BadFloat and avoid any argument; however, I chose to call the IsNAN and I'm not changing it without a much better reason. As far as I can tell, the only reason +INF and -INF are not documented as special cases of NaN is that some people have trouble with the idea that a floating point bit pattern can be both NaN and INF. The difference is rarely important. It's akin to carefully measuring out exactly 2 cups of water to boil noodles; you can measure it out with a measuring cup making sure that water level is exactly at the 2 cup mark while I fill my 1 quart pot about half full -- the end result will taste the same. Greg --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.research.att.com/~austern/csc/faq.html ]