On 1/3/2017 12:34 PM, Tony Finch wrote:
Joe Touch <touch(_at_)isi(_dot_)edu> wrote:
We really need to separate the frames of reference of time - there's no
need for smear for internal "seconds since epoch" time.
Well, the problem is that "seconds since the epoch" is not a count of
UTC seconds,
Correct; it's UTC-(leap seconds since epoch start).
it is a mapping from broken-down time to a linear time,
Seconds since epoch is as linear as it gets.
and the mapping is defined in a way that requires 86400 seconds per
day and does not accommodate leap seconds.
The conversion of epoch seconds to larger units is where the leap
seconds is counted.
A "day" as a unit of time is not exactly 86400 seconds (if it were, we
wouldn't need leap seconds).
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap04.html#tag_04_16
Leap smear exists mainly because "seconds since the epoch" does not
allow for leap seconds.
Seconds since epoch is unambiguous and linear.
It is in the conversion to other representations or aggregations where
leap seconds needs to be considered.
Joe