> In other words, if I can assure that data exported and then imported
> will always, under all circumstances, compare the same to the original,
> would that be enough of a requirement? In other words, if I offer a
> format that is assured of preserving both mantissa and exponent
> precision and range, as well as all extra attributes (+/-Infinity and
> NaN), but does not guarantee that the semantically identical constructs
> are told apart (+0 vs. -0, and the different NaNs), would that format be
> acceptable?
If you care about the +/- for +/-Infinity, you must also care about +/-0
too, so you get the right type of infinity if you divide with 0... so +0
and -0 are far from being semantically identical.
Cheers,
Csaba.