Joe Touch <touch@xxxxxxx> wrote: > > When UTC adds a leap second, nothing different happens to POSIX time. Clearly not. Either it jumps backwards at the start of the leap second, or at the end of the leap second, or it stops for a second, or it runs slow for some period of time in a controlled manner (e.g. leap smear) or an uncontrolled manner (NTP swinging around in a wild effort to resync). The POSIX formula that specifies the translation from UTC to time_t implies that it jumps back at the end of the leap second. http://pubs.opengroup.org/onlinepubs/9699919799.2016edition/basedefs/V1_chap04.html#tag_04_16 Tony. -- f.anthony.n.finch <dot@xxxxxxxx> http://dotat.at/ - I xn--zr8h punycode South German Bight, Humber, Thames: Southwesterly 4 or 5, increasing 6 at times. Slight or moderate. Occasional rain, fog patches. Moderate or good, occasionally very poor.