John Sauter <John_Sauter@systemeyescomputerstore.com> wrote:
I have always assumed that the problem of having access to TAI was solvable, using the same mechanisms that let computers know about time zones. From the application's point of view, TAI would just be another zone, with the mechanism for converting between TAI and UTC in a library.
Am I overlooking something?
I think the things that are missing are: * A standard representation of TAI (as discussed in this thread). There's some convergence here already: I believe PTP matches POSIX time at the start of 1972, and counts TAI seconds after that point, which matches the tz "right" zones. But there isn't a solid meaning outside the period of 1972 - present. * A standard API for getting the kernel's idea of TAI and its leap indicator - something like a simplified ntp_gettime but aimed at applications rather than ntp daemons. Applications need to see the leap indicator so that they can tell if the kernel's idea of leap seconds matches the application's idea. They might differ if NTP isn't working or if NTP uses leap smear. * A standard way to obtain the leap second table. This requires some combination of either the tzdist protocol or normal software updates, combined with support in tz for using TAI without stepping in the "right" timezone swamp. Repeat for each language's standard library. Windows is supposed to have TAI support but I haven't looked into how it works. Tony. -- f.anthony.n.finch <dot@dotat.at> https://dotat.at/ Fair Isle, Faeroes: East or northeast 4 to 6, occasionally 7 at first. Slight or moderate in eastern Fair Isle, otherwise moderate or rough. Showers. Good, occasionally moderate.