Re: Programming a calendar system

Whups, got cut off.

You decided to make the starting point August 26, 986 (or -986).
The next question is: what time of day on our calendar corresponds
to the start of the Arégan day?  I think midnight would be asking too
much of coincidence.

Also, you need to decide whether that's August 26, [-]986 in the Julian
calendar (which is what historians usually use for such dates) or
Gregorian.  In the year -986 (which under the usual convention is -986
AD = 987 BC, because 1 BC was the year before 1 AD, with no year in between;
so 0 AD = 1 BC, -1 AD = 2 BC etc), neither calendar had yet been
invented; in the year 986 the Julian was in place but the Gregorian had
yet to come into being.

So here are your options:

Julian                  Gregorian               time_t at midnight UTC
August   26, 987 BC     August 17, 987 BC       -93,262,665,600
September 4, 987 BC     August 26, 987 BC       -93,261,888,000
August   26, 986 AD     August 31, 986 AD       -31,031,078,400
August   21, 986 AD     August 26, 986 AD       -31,031,510,400

Those time_t values are bigger than most fixed-width integer data types
can hold, though.  It probably makes more sense to deal in whole days
(divide the times by the number of seconds in a day = 86,400) to
determine the date and then treat the time of day separately.

-Mark

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