From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Mark H Weaver Newsgroups: gmane.lisp.guile.bugs Subject: bug#22034: time-utc->date shows bogus zone-dependent leap second Date: Mon, 29 Oct 2018 03:16:19 -0400 Message-ID: <87a7mx8boh.fsf@netris.org> References: <20151127195146.GB28472@fysh.org> <87a7n847o5.fsf@netris.org> <87va5u8q7o.fsf@netris.org> <871s89ajql.fsf@netris.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: blaine.gmane.org 1540797370 6766 195.159.176.226 (29 Oct 2018 07:16:10 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 29 Oct 2018 07:16:10 +0000 (UTC) User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) Cc: zefram@fysh.org, 22034@debbugs.gnu.org, 22034-done@debbugs.gnu.org To: John Cowan Original-X-From: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Mon Oct 29 08:16:05 2018 Return-path: Envelope-to: guile-bugs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gH1mO-0001dE-K6 for guile-bugs@m.gmane.org; Mon, 29 Oct 2018 08:16:04 +0100 Original-Received: from localhost ([::1]:43896 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gH1oV-0005FA-4q for guile-bugs@m.gmane.org; Mon, 29 Oct 2018 03:18:15 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:51205) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gH1oO-0005Eg-87 for bug-guile@gnu.org; Mon, 29 Oct 2018 03:18:09 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gH1oL-0008GU-E7 for bug-guile@gnu.org; Mon, 29 Oct 2018 03:18:08 -0400 Original-Received: from debbugs.gnu.org ([208.118.235.43]:45620) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gH1oL-0008GO-5u for bug-guile@gnu.org; Mon, 29 Oct 2018 03:18:05 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1gH1oJ-0000q5-Bn for bug-guile@gnu.org; Mon, 29 Oct 2018 03:18:05 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Mark H Weaver Original-Sender: "Debbugs-submit" Resent-CC: bug-guile@gnu.org Resent-Date: Mon, 29 Oct 2018 07:18:03 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 22034 X-GNU-PR-Package: guile X-GNU-PR-Keywords: Original-Received: via spool by 22034-done@debbugs.gnu.org id=D22034.15407974323155 (code D ref 22034); Mon, 29 Oct 2018 07:18:03 +0000 Original-Received: (at 22034-done) by debbugs.gnu.org; 29 Oct 2018 07:17:12 +0000 Original-Received: from localhost ([127.0.0.1]:49875 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gH1nU-0000oo-Eb for submit@debbugs.gnu.org; Mon, 29 Oct 2018 03:17:12 -0400 Original-Received: from world.peace.net ([64.112.178.59]:43308) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gH1nS-0000oX-Fy; Mon, 29 Oct 2018 03:17:10 -0400 Original-Received: from mhw by world.peace.net with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gH1nM-0004px-IE; Mon, 29 Oct 2018 03:17:04 -0400 In-Reply-To: (John Cowan's message of "Sun, 28 Oct 2018 19:58:03 -0400") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-guile@gnu.org List-Id: "Bug reports for GUILE, GNU's Ubiquitous Extension Language" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-guile-bounces+guile-bugs=m.gmane.org@gnu.org Original-Sender: "bug-guile" Xref: news.gmane.org gmane.lisp.guile.bugs:9249 Archived-At: Hi John, John Cowan writes: > On Sun, Oct 28, 2018 at 4:40 PM Mark H Weaver wrote: > > The difference between the two measuring tapes is that they assign > different numbers to the markings, and moreover that the UTC analogue > has a small handful of places where two adjacent markings have the same > number assigned, and all subsequent numbers are shifted by 1. > > Now I think you are entirely right here, modulo a single term: what you are > calling "UTC", I call (and I think correctly), "Posix". It is Posix time that > has two identical adjacent markings. > > 126230400 |------------ > 126230400 |------------ > > The numbers here are not UTC seconds since the Epoch, but Posix seconds > since the Epoch. Here's a more detailed display of the same leap second that I chose for my example, which you quoted above: +-----------------------------------------------------------+ | TAI seconds UTC seconds | | since since | | midnight UTC midnight UTC | | 1 Jan 1970 1 Jan 1970 Result of 'time-tai->date'| |-----------------------------------------------------------| |$2 = ((126230410 126230398 "1973-12-31T23:59:58Z") | | (126230411 126230399 "1973-12-31T23:59:59Z") | | (126230412 126230400 "1973-12-31T23:59:60Z") | | (126230413 126230400 "1974-01-01T00:00:00Z") | | (126230414 126230401 "1974-01-01T00:00:01Z")) | +-----------------------------------------------------------+ The table above illustrates my understanding of the relationship between "TAI seconds since midnight UTC on 1 Jan 1970", "UTC seconds since midnight UTC on 1 Jan 1970" and the date object expressed in UTC. See my previous email for the code to produce the table above using SRFI-19. If I understand correctly, based on your last sentence that I quoted above, you believe that the numbers I've given in the second column are not UTC seconds since the epoch, and that there is confusion here between UTC seconds and Posix seconds. Can you please be more concrete and tell me what numbers you think should be in the second column, to properly reflect the column heading? I'm not asking for a prose description, but for the actual numbers. If the table above is incorrect, then it would be good to report the problem to the SRFI-19 mailing list, because the current SRFI-19 reference implementation produces the same table. Thanks, Mark