Re: [boost] [serialization]Serialisation/deserialisation offloating-point values

From: Robert Ramey (ramey_at_[hidden])
Date: 2006-03-15 11:04:56

As has been noted, the serialization library inherits the behavior of
the basic_stream library used in its implementation.  One could
try another library - e.g. STLPort.  If you need a solution for some
specific datum in a specific application you could apply the
binary_object wrapper and serialize the binary representation
of the double.  Of course you're back the the problem of
portable representation of floats - another problem discussed
on this list which has never arrived at a successful resolution.

Robert Ramey

John Maddock wrote:
>> Using 100 tests with nextafter, starting with the value you found
>> faulty, I find 38 failures (all one bit wrong on input)  - about the
>> one third I found in previous tests.
>
> Oh shucks: I wonder would this be solved by using the solution I
> often see
> in the literature when an author wants to give a binary floating
> point value exactly: which is to represent it as an integer + a base
> 2 exponent.  Values in that form can be serialised/deserialised
> exactly using ldexp/frexp, but unfortunately aren't very human
> readable (or rather are open to mis-interpretation because the
> exponent is a power of 2 not 10).  This
> format is similar to the "A" format specifier in the C99 version of
> printf, and I believe the code is quite simple as well BTW,
>
> John.
>
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