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=-0.4 required=5.0 tests=AC_FROM_MANY_DOTS,BAYES_00 autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,9fbc059a74d74032 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2001-05-29 07:57:05 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!fr.usenet-edu.net!usenet-edu.net!wanadoo.fr!isdnet!psinet-france!psiuk-f4!psiuk-p4!uknet!psiuk-n!news.pace.co.uk!nh.pace.co.uk!not-for-mail From: "Marin David Condic" Newsgroups: comp.lang.ada Subject: Re: Leap Seconds Date: Tue, 29 May 2001 10:43:36 -0400 Organization: Posted on a server owned by Pace Micro Technology plc Message-ID: <9f0ciq$itb$1@nh.pace.co.uk> References: <9elpii$30i$1@nh.pace.co.uk> <3B0ED67B.E40A4E06@averstar.com> NNTP-Posting-Host: 136.170.200.133 X-Trace: nh.pace.co.uk 991147418 19371 136.170.200.133 (29 May 2001 14:43:38 GMT) X-Complaints-To: newsmaster@pace.co.uk NNTP-Posting-Date: 29 May 2001 14:43:38 GMT X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 5.50.4522.1200 X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4522.1200 Xref: archiver1.google.com comp.lang.ada:7844 Date: 2001-05-29T14:43:38+00:00 List-Id: Further research into leap-seconds indicates that effectively, they are unpredictable. The International Earth Rotation Service sort of announces them whenever they think it is necessary and they can be positive or negative. Hence, unless one has a lookup table for leap-seconds in the past, it would not be possible to know when they existed. (The first happened in 1972) It is even more problematic if you are calculating some time in the future since you don't know when they happen. (Customarily, leap-seconds are announced in December or June, but they need not happen every year.) While a handful of seconds over a number of years may not be a big deal in most cases, I could easily imagine where they might make a difference. (Especially when trying to sync up with something else that is using a time base somewhere in the past and wondering if it counts the leap seconds and you don't. Source A counts them, source B doesn't and you're in the middle trying to figure out 'does anybody really know what time it is?') More info at: http://maia.usno.navy.mil/eo/leapsec.html Now I'm wondering what I'm supposed to do with the requirement that I count them??? :-) MDC -- Marin David Condic Senior Software Engineer Pace Micro Technology Americas www.pacemicro.com Enabling the digital revolution e-Mail: marin.condic@pacemicro.com Web: http://www.mcondic.com/ "Tucker Taft" wrote in message news:3B0ED67B.E40A4E06@averstar.com... > > There is no requirement to support leap seconds. > I would guess it is safe to say that leap seconds > are *not* supported in any Ada implementation. > There might even be ACATS/ACVC tests that are actively unfriendly > to leap seconds, though I don't know for sure. >