Tom Van Baak wrote > John Sauter wrote: >> I had thought that TAI-UTC was the only information needed to convert >> from TAI to UTC [...] Is >> my new belief correct that you need both TAI-UTC and the knowledge that >> a leap second is in progress to convert from TAI to UTC? > > Hmm, it sounds like your new belief is wrong too. [...] The table is all > you need to decide how to convert between TAI/UTC and UTC/TAI. Yes, the > code gets tricky near +/- N seconds of midnight, where N is |TAI-UTC|.
I think John's point is that if all I have is a TAI timestamp t, and an interface to a leapsecond table that returns taioffset(t) for TAI time t, that's not quite enough to unambiguously compute the corresponding UTC timestamp. If I take t and subtract taioffset(t), I don't know whether the UTC result I get should end in :60, so to speak. As it happens, just last week I write a TAI-to-UTC conversion function, and I had to invent a new interface into my leapsecond table: it returns the TAI-UTC offset for a given time t, *and* it returns the time of the transition nearest to t, which is what's needed to make the leap-second determination John is talking about. _______________________________________________ LEAPSECS mailing list [email protected] https://pairlist6.pair.net/mailman/listinfo/leapsecs
