On Sat, Oct 20, 2018 at 5:43 PM Mark H Weaver <mhw@netris.org> wrote:

If I understand correctly, 'time-utc->date' should never return a date
object with 60 in the seconds field, because those extra seconds have no
representation in time-utc.  They only have representations in time-tai
and time-monotonic.

As I understand it, this is incorrect.  UTC days can contain either 86400 or 86401 seconds (or in principle a different number), depending on whether the day has a leap second.  It is *Posix* time, not UTC time, that contains a fixed number of seconds per day, or more accurately that assigns a label from 0 to 864399 to the seconds of a day, and can assign the same label to more than one second (or in principle could assign one or more labels to no second) on a leap-second day. Consequently, a broken-down time can indeed return 60 in the seconds field, but only for a UTC clock, never for a Posix clock.

This error is repeated in a number of your later messages, but I'll respond only to this one.

-- 
John Cowan          http://vrici.lojban.org/~cowan        cowan@ccil.org
Tautology is something that is tautological.  --Francois-Rene Rideau