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

I don't think there's a single standard to such things at the moment, however there are multiple standards which such things may conform to: ISO 8601 for example.

ICU's own date/time handling is a cross-language (C/C++ and Java) and multi-platform library.

It handles dates and times internally, typically, using for a single time a UDate (C/C++) or a java.util.Date/long (Java), as number of milliseconds since 1-1-1970, or a Calendar object which is specific to the type of calendar (Gregorian vs Hijri, etc). Durations are available for formatting. Leap years are calculated as part of calendar systems, and leap seconds are assumed to be handled by the underlying operating system. DST/Timezone data is kept up to date with 'the tz database' sometimes referred to by its author's surname, Olson.

Hope this has answered your question some as regards ICU.