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From: Paul A Bristow (pbristow_at_[hidden])
Date: 2006-08-02 15:35:19


 

| -----Original Message-----
| From: boost-bounces_at_[hidden]
| [mailto:boost-bounces_at_[hidden]] On Behalf Of Gennaro Prota
| Sent: 02 August 2006 19:34
| To: boost_at_[hidden]
| Subject: Re: [boost] Spurious warning in lexical_cast.hpp
|
| On Wed, 2 Aug 2006 14:11:20 +0100, "Paul A Bristow"
| <pbristow_at_[hidden]> wrote:
|
| >But this is STILL the WRONG formula for the number of digits!
| >
| >It should be max_digits10.
| >
| >stream.precision(2 + std::numeric_limits<Source>::digits *
| 301/1000);
| >
| >PLEASE can we get at long last get this right so that floats can be
| >serialized without losing a few bits.
|
| I presume lexical_cast will be totally rewritten not too far in the
| future, to optimize some specific conversions, as also recently
| discussed. That's why I've tended to postpone issues about it. But if
| you really feel strongly about this specific problem (please, say "I
| do so swear" ;-)) I'll give it a thought.
|
| But...: are you serializing floating point values by means of
| lexical_cast?

No - I meant 'stringizing' - but the same wrong formula has been used for
serialization.

Fortunately it just happens to give the right result for double - and most
people are using that.

But as a QOI issue, I think it looks bad, and may bite some poor
unsuspecting user.

Paul

---
Paul A Bristow
Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB
+44 1539561830 & SMS, Mobile +44 7714 330204 & SMS
pbristow_at_[hidden]
 

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