RE: [boost] Re: Re: is_nan

From: Paul A. Bristow (boost_at_[hidden])
Date: 2003-07-08 17:13:46

I think this would be excellent (and overdue). It needs to support double and
long double (and facilitate UDTs too if possible).

There is also the matter of signalling and quiet NaN. Although signalling NaN
may cause an hardware exception if enabled, I suspect it is more useful if isnan
returns ture for both types of NaN.  At least we should make this clear.  I
think this is what MSVC 7.1 does but the documentation is thin.

There is also a single IEEE FP pattern called 'indeterminate' or what Intel call
'NotAVal" (ox1fffe000...) which might become useful as a Portable Standard
"missing value" marker if portably supported?

And can anyone help with allowing one to easily customise the display of NaNs?
(and infs, max, min...?) I believe that a new (derived) num_put facet is the way
to do this.  Does anyone have an actual implementation of this to contribute
too?

Paul

Paul A Bristow, Prizet Farmhouse, Kendal, Cumbria, LA8 8AB  UK
[phone]   Mobile [phone]
Mobile mailto:pabristow_at_[hidden]
mailto:pbristow_at_[hidden]

| -----Original Message-----
| From: boost-bounces_at_[hidden]
| [mailto:boost-bounces_at_[hidden]]On Behalf Of Joel de Guzman
| Sent: Monday, July 07, 2003 5:15 PM
| To: Boost mailing list
| Subject: Re: [boost] Re: Re: is_nan
|
|
| Fernando Cacciola <fernando_cacciola_at_[hidden]> wrote:
| > Fernando Cacciola <fcacciola_at_[hidden]> wrote in message
| > news:be780m$ts7$1_at_main.gmane.org...
| >>
| >> Thanks to Gabriel we may have an is_nan() right now.
| >>
| > Oops!
| > It was Joel de Guzman who offered his is_nan() implementation.
| >
| > Sorry Joel :-)
|
| No problem. I thought Gaby also offered an implementation ahead of me.
| So you guys are interested then? It would really be nice to have a
| common boost implementation. I'll put it in the sandbox tomorrow.
|
| --
| Joel de Guzman
| joel at boost-consulting.com
| http://www.boost-consulting.com
| http://spirit.sf.net
|
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