From: Stan Heckman <stan at stanheckman.com>
> "Eric Ulevik" <eau at fast.fujitsu.com.au> writes:
> > The point is that the second primitive must take UTC value and time zone
as
> > input, and return the local time. Also note this is not a 1:1 map.
> How not 1:1? Are there two local times that correspond to the same UTC
> time, or is it two UTC times that correspond to the same local time?

Consider setting back the clock 1 hour at 2am.

Reading your clock every half hour:
0000 0030 0130 0200 0230 0200 0230 0300 0330 0400

The local time 0230 is repeated twice; it represents two different instants.

> No matter how much I learn about time, there always seems to be more
> to learn.

Time is not overly complicated, but it's not as simple as most programmers
think. The key is to use a sensible basis for measurement (eg. UTC). Perform
all your calculations using this basis, and treat everything else as
labelling rules (eg. local time).

A good example to consider is drawing charts with an x-axis as given above.

Everything you need, including code and up-to-date time zone data, can be
found at ftp://elsie.nci.nih.gov/pub/

Regards,

Eric Ulevik