From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,7dadb26e573572d X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-12-18 11:04:38 PST Path: archiver1.google.com!news1.google.com!sn-xit-02!sn-xit-04!sn-xit-06!sn-post-01!supernews.com!corp.supernews.com!not-for-mail From: "Randy Brukardt" Newsgroups: comp.lang.ada Subject: Re: ada calendar Date: Thu, 18 Dec 2003 13:03:26 -0600 Organization: Posted via Supernews, http://www.supernews.com Message-ID: References: X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4807.1700 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4910.0300 X-Complaints-To: abuse@supernews.com Xref: archiver1.google.com comp.lang.ada:3541 Date: 2003-12-18T13:03:26-06:00 List-Id: "Thomas Wolf" wrote in message news:MPG.1a412f88b61dac9c989681@news.ip-plus.ch... > rieachus@comcast.net wrote: > > The latest version of the proposed additions for Ada 0Y can be found at: > > http://www.ada-auth.org/cgi-bin/cvsweb.cgi/AIs/AI-00351.TXT?rev=1.2> > > I see that this proposal includes some functionality for dealing with > leap seconds. It proposes (among other things) ... > How is this supposed to work if Left or both Left and Right are in > the future? You cannot predict when the next leap second will be > inserted -- it depends on the irregularities of Earth's rotation, > and IERS inserts a leap second whenever necessary (well, at the end > of June or December) to keep the difference between UT1 und UTC < > 0.9 sec. > > Also implementing this for past dates needs a look-up table. No, you failed to read the Implementation Advice. The intent is that this is mapped to whatever functionality is provided by the underlying timebase. In particular, if the timebase doesn't provide leap second information, all of these routines should return zero for the number of leap seconds. (And, by definition, that should be true for times in the future.) The only reason for these functions is so that using a timebase that does provide leap seconds (and they are getting more common) won't screw up programs. Note that I personally think these leap second functions are a mistake. There are sometimes 86401.0 seconds in a day, and Ada should simply be honest and say that. (Indeed, doing so makes the other functions in this AI more critical, because the assumptions used in typical code are wrong.) In any case, the ARG is far from a resolution on this proposal. (We didn't discuss it in San Diego, the only Amendment AI that we didn't look at.) Randy Brukardt ARG Editor (and author of AI-351).