Re: [boost] [serialization] facets for non-finite numbers

From: Paul A Bristow (pbristow_at_[hidden])
Date: 2006-08-03 08:00:08

|  -----Original Message-----
|  From: boost-bounces_at_[hidden] 
|  [mailto:boost-bounces_at_[hidden]] On Behalf Of Johan Råde
|  Sent: 03 August 2006 09:54
|  To: boost_at_[hidden]
|  Subject: Re: [boost] [serialization] facets for non-finite numbers
|  
|  I have uploaded a new version to the vault.
|  
|  This version features:
|  
|  1. Strict C99 conformance:
|          Output is consistent with C99. (In particular, 
|  negative NaN is 
|  written as "-nan".
|          All representations allowed by C99 are recognized as input.
|  
|  2. Optional support for negative 0.
|  
|  3. Clean build with VC++ 7.1 at warning level 4.
|  
|  4. Improved documentation.
|  
|  This version is backwards compatible with earlier versions.
|  
|  The code comes with a test program. I have only run the test 
|  program on 
|  VC++ 7.1.
|  If you run the test program on any other platform, please report the 
|  result to me.
|  Both good and bad results are of interest.
|  
|  Many thanks to Paul Bristow, John Maddock and Gennaro Prota 
|  for valauble comments.

This compiles and run OK on MSVC 8.0 after automatic conversion of the 7.1
vcproject.

No warnings either :-))  

But of course, the proof of portability is other endians and layouts etc :-)

I have yet to get my head round predicting if it will work but looks rather
plausible.

The only final requirement for TR1 is to template it to provide

  template<class T> bool signbit(T x);

Additions I can see are checks for:

1  If T not specialized then I returning false may be the obvious option.

But John Maddock's prototype real_concept is NOT specialised,

and yet it would be nice if signbit worked with real_concept.

It would also be nice if it worked with

NTL quad_float (also == Darwin long double and doubledouble) and RR types,

and big_integer when we get one.

I will have to think about this.

2  If is_specialized nad is_signed == false, (all unsigned types) then we
must surely return false.

So many thanks to you for your valuable work on this.

Paul

---
Paul A Bristow
Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB
[phone] & SMS, Mobile [phone] & SMS
pbristow_at_[hidden]