Re: [boost] Stream input and output of NaN and infinity

From: Guillaume Melquiond (guillaume.melquiond_at_[hidden])
Date: 2006-05-16 01:54:12

Le lundi 15 mai 2006 à 22:21 -0700, Jeff Garland a écrit :
> In date_time there's -inf, +inf, and not_a_date_time.  There's 
> no union internally used to represent them.  These values are extremely 
> useful for writing real programs and have obvious mappings into the real 
> world -- trust me, I've used them in a real world scheduling system. In 
> fact, since date_time uses integers internally the special values are 
> simply implemented as a reserved number value.  nadt is essentially 
> max_int, +inf == max_int - 1 and -inf == min_int.

For symmetry purpose, I would have chosen nadt == min_int, +inf =
max_int, -inf = min_int + 1. That way, in usual two-complement
representations, there is as much positive than negative finite values
and infinities have the same absolute representation. Just pointing it
out in case nobody did before.

Best regards,

Guillaume