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From: Robert A Duff <bobduff@world.std.com>
Subject: Re: Ada Calendar oddity <was Re: C date package>
Date: 2000/05/10
Message-ID: <wccn1lyjz94.fsf@world.std.com>#1/1
X-Deja-AN: 621565628
Sender: bobduff@world.std.com (Robert A Duff)
References: <l0313030eb53d1408aee7@[144.205.16.58]>
 <39176D85.603D7AEC@research.canon.com.au>
 <39178DEA.FD2C20FA@research.canon.com.au> <8f92o1$6v$1@nnrp1.deja.com>
 <3918BB77.693C70D6@research.canon.com.au> <8fahfv$mgt$1@nnrp1.deja.com>
 <slrn8hioca.101.randhol+nospam@kiuk0156.chembio.ntnu.no>
Organization: The World Public Access UNIX, Brookline, MA
Newsgroups: comp.lang.ada
Date: 2000-05-10T00:00:00+00:00
List-Id: <comp.lang.ada>

randhol+nospam@pvv.org (Preben Randhol) writes:

> I was looking yesterday in the RM and found that Year in the
> Ada.Calendar was defined until 2099 only. I have search on deja, but I
> cannot find any reason for it to be defined only to 2099.

The reason for the range 1901..2099 is that leap year calculations are
simpler (and more efficient) in this range -- in this range, all years
divisible by 4 are leap years (including 2000).  1900 and 2100 are not
leap years.

One can argue about whether that's a *good* reason, but it's the reason.

What range would *you* suggest?

If I were designing such a package, I would think about the number of
bits needed to represent the number of seconds (or nanoseconds?) in the
range.

- Bob