HELP DATETIME                    Epoch seconds <-> ISO 8601, all in UTC

    uses datetime;

Pure-integer date/time conversions (the standard civil-date
algorithms), so results are identical on every platform and there is
no timezone state: everything is UTC ("Z").

dt_now() -> EPOCH
    Current time as integer epoch seconds (sys_real_time).

dt_iso(EPOCH) -> S
    'YYYY-MM-DDTHH:MM:SSZ', e.g. dt_iso(0) = '1970-01-01T00:00:00Z'.
    Negative (pre-1970) values work.

dt_parse_iso(S) -> EPOCH
    Accepts 'YYYY-MM-DD', 'YYYY-MM-DDTHH:MM:SS', an optional trailing
    'Z', and a space instead of 'T'.  Mishaps on anything else.
    Round trip: dt_parse_iso(dt_iso(t)) == t.

dt_fields(EPOCH) -> {YEAR MONTH DAY HOUR MINUTE SECOND}

dt_days_from_civil(Y, M, D) -> DAYS
    Days since 1970-01-01 for a (proleptic Gregorian) civil date —
    the building block, exported for calendar arithmetic.

Example — age of a file in whole days:

    uses datetime, fileutils;
    (dt_now() - file_mtime('README.md')) div 86400 =>

Note there is no timezone or locale handling; convert at the edges of
your program if you need local time.

See also: sys_real_time, LIB * FILEUTILS, tools/tests/test_datetime.p
(vectors cross-checked against Python's calendar.timegm).

--- pop/help/datetime