Re: Re: Re: Re: Re: deco-Math project, step 00_a: exact bin and dec 'ranges' (in gnumeric).

[Morten Welinder <mortenw gnome org>]

> i'd like to learn how rounding for display is done, some of it might be useful for improvements i'm 
> thinking about.

string-to-value is, basically, the C library's strtod.  ("Basically"
because there are complications like decimal comma, thousands
separators, and probably other such things.)

value-to-string is in goffice/math/go-dtoa.c and is based on musl's
printf code.  It's changed to handle things like decimal comma.

As far as I know, both ways have full accuracy in the round-to-nearest
sense under two conditions: (1) a sane C library -- glibc is fine, and
(2) ieee-854 semantics of double and long double -- x86 is fine.

M.