How do libraries in different programming languages handle Date & Time, Timestamps & Durations, Leapseconds & -years, DSTs & Timezones, …?

Question

Is there a standard body or a specific normative way how time-related things should be implemented in practice (like ICU for Unicode-related tasks) or is this curre

Answer 1

You mention Python in an earlier comment.

Python's builtin datetime support (docs) is pretty practical, but you have to use a third-party timezone database such as pytz (docs) to make it close to complete. And, as the pytz docs mention, you may still have problems with adding deltas to times right around DST transitions if you aren't careful.

It was once the case that eGenix's mx.DateTime was the way to go if datetime didn't do it for your application, particularly for string to timestamp conversions, but dateutil seems to be popular these days (I haven't used it though).