From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/4378 Path: news.gmane.org!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCHv2] Add support for leap seconds in zoneinfo files Date: Fri, 6 Dec 2013 01:29:08 -0500 Message-ID: <20131206062908.GY24286@brightrain.aerifal.cx> References: <529588D8.3020006@skarnet.org> <20131127184307.GN1685@port70.net> <52965735.9070409@skarnet.org> <529FD33A.8000509@skarnet.org> <20131205144311.GG24286@brightrain.aerifal.cx> <52A0AA6A.60608@skarnet.org> <20131205164022.GK24286@brightrain.aerifal.cx> <52A11C0D.1080705@skarnet.org> <20131206004535.GT24286@brightrain.aerifal.cx> <52A12548.80508@skarnet.org> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1386311356 32670 80.91.229.3 (6 Dec 2013 06:29:16 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 6 Dec 2013 06:29:16 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-4382-gllmg-musl=m.gmane.org@lists.openwall.com Fri Dec 06 07:29:22 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1Vooug-0005Dc-0C for gllmg-musl@plane.gmane.org; Fri, 06 Dec 2013 07:29:22 +0100 Original-Received: (qmail 5415 invoked by uid 550); 6 Dec 2013 06:29:21 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 5407 invoked from network); 6 Dec 2013 06:29:21 -0000 Content-Disposition: inline In-Reply-To: <52A12548.80508@skarnet.org> User-Agent: Mutt/1.5.21 (2010-09-15) Xref: news.gmane.org gmane.linux.lib.musl.general:4378 Archived-At: On Fri, Dec 06, 2013 at 01:15:52AM +0000, Laurent Bercot wrote: > > >Regarding the unfortunate coupling of timezone and leapsecond data > >into a single file, do the zoneinfo files with leapseconds have their > >timezone transition times stored in POSIX time or TAI? > > TAI-10 (the 10 seconds offset is so it's the same as POSIX time > before 1972). As I said, it's the only behaviour that makes sense: > we're counting a number of seconds and we want it to be unambiguous. > POSIX time would create an ambiguity for the very moment when a leap > second happens, which defeats the purpose. The reason I asked is that it means, if you're using TAI-10, you have to have matching zoneinfo files for the daylight time transitions to work correctly. This really complicates the matter of having POSIX/TAI and TZ be separate... > >At the very least they would have some overhead determining that > >leapseconds aren't in use. > > Indeed, one test at executable start. :) At first use. Definitely not at executable start. > Do you have any idea what form this test would take, if we're opting > away from TZ ? No, I don't know. Rich