GtkSpinButton output

[Johannes =?utf-8?B?V2Vpw59s?= <johannes weissl gmx de>]

Hello,

my program contains a GtkSpinButton, which can hold very large
values (up to MAX_DBL). I know that the user can enter
floating-point numbers (e.g. 2e58), but they get always displayed
as really long "normal" numbers.

Something like "%g" in printf would be nice. Maybe it could
be done through signals, but they are not documented in the API ...
any ideas? (sorry for my bad English)

-- 
cu,
Johannes Weißl