[tz] Fractional seconds in zic input

[Michael Douglass]

On 2/5/18 13:50, Paul Eggert wrote:
> On 02/05/2018 10:46 AM, Howard Hinnant wrote:
>> If two clients (different platforms) want to maintain the invariant 
>> that equal time_points remain equal after mapping, then they must 
>> operate at the precision of the mapping (or finer).
> We already have clients that don't want to do that, as they discard 
> sub-minute resolution. But I take your point that some clients may 
> want to do that and we should cater to this subclass of clients too. 
> In that case, how about if we stick to at most 1-ms resolution in the 
> data, and note in zic.8 that 1 ms resolution is the way to go? I say 
> "1 ms" because of Steve Allen's email.
>
The current representation of time in calendars is only down to the 
second and that has been an issue for industries (financial, smart grid 
etc) that want to represent that data. I can ask but I'm sure that 
milliseconds are too coarse. The problem of whether DST applies for 90 
nanoseconds after 2am is something they will have to resolve.