From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp10.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms5.migadu.com with LMTPS id 6FY6NoKC2mPUJAAAbAwnHQ (envelope-from ) for ; Wed, 01 Feb 2023 16:17:23 +0100 Received: from aspmx1.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp10.migadu.com with LMTPS id gDBlNYKC2mOkxwAAG6o9tA (envelope-from ) for ; Wed, 01 Feb 2023 16:17:22 +0100 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id 8CD3F6E0D for ; Wed, 1 Feb 2023 16:17:22 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pNEqn-0006kH-F5; Wed, 01 Feb 2023 10:16:41 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNEqe-0006i9-QH for emacs-orgmode@gnu.org; Wed, 01 Feb 2023 10:16:32 -0500 Received: from ciao.gmane.io ([116.202.254.214]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNEqc-0004R7-Vg for emacs-orgmode@gnu.org; Wed, 01 Feb 2023 10:16:32 -0500 Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1pNEqY-0008cD-RM for emacs-orgmode@gnu.org; Wed, 01 Feb 2023 16:16:26 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: emacs-orgmode@gnu.org From: Max Nikulin Subject: Re: POSIX TS spec reverses the meaning of TZ offset compared to ISO (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda) Date: Wed, 1 Feb 2023 22:16:16 +0700 Message-ID: References: <87fsc88aq9.fsf@localhost> <63c7dd3d.170a0220.6b4d6.f84f@mx.google.com> <877cxk6oeu.fsf@localhost> <63c86454.170a0220.80970.652d@mx.google.com> <63c8f5a6.170a0220.ea8cf.7f96@mx.google.com> <63c9b654.170a0220.d82d2.4254@mx.google.com> <87mt6e86sr.fsf@tsdye.online> <63c9d976.620a0220.a7d40.113b@mx.google.com> <87tu0mjb24.fsf@tsdye.online> <63ca1283.170a0220.5bc81.0fdd@mx.google.com> <87pmb9k8oi.fsf@tsdye.online> <3035CDD5-41DD-4516-9E4E-9E0DF16BE2E0@gmail.com> <87lelo8c9r.fsf@localhost> <2150768.1675077958@archlinux> <87tu063ox2.fsf@localhost> <87r0v9sio1.fsf@christianmoe.com> <87edr9lgq6.fsf@localhost> <87o7qdsf7h.fsf@christianmoe.com> <87v8kljz3n.fsf@localhost> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Content-Language: en-US In-Reply-To: <87v8kljz3n.fsf@localhost> Received-SPF: pass client-ip=116.202.254.214; envelope-from=geo-emacs-orgmode@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: 27 X-Spam_score: 2.7 X-Spam_bar: ++ X-Spam_report: (2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_ADSP_CUSTOM_MED=0.001, FORGED_GMAIL_RCVD=1, FORGED_MUA_MOZILLA=2.309, FREEMAIL_FORGED_FROMDOMAIN=0.249, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.25, NICE_REPLY_A=-0.09, NML_ADSP_CUSTOM_MED=0.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-orgmode@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "General discussions about Org-mode." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-orgmode-bounces+larch=yhetil.org@gnu.org Sender: emacs-orgmode-bounces+larch=yhetil.org@gnu.org X-Migadu-Flow: FLOW_IN X-Migadu-Country: US ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1675264642; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post; bh=6IEEkWY0Wq4MDKgwRXpvNusGCwMUa3AUNBKH9moOh/Q=; b=ew7Bny8tsLCxcg3wxE13OCKsSBDvNNR/WsevEEHOB5IdkmOg5hZPtF0E8lsdZ0zXAmkpgy q7O5XNTzs2JqWe+nu9uQnviy2Vqh3PiQRF8l1IDbuKrpHKL1t9S5lTC4XzB0B1NeqXBqEC PEvBMdHqe76E6f7HyBuCXN1TkouZev2cpNaql+lV5WqB9FOOC8XzxLCvgtOa6Itczin2Hl Kma/U+qYmTzjjWQ0ig7nh9v0j6eQOaVUAH+ptkj738OtF5FVqlYQ/G4P+snrNsQlwI0OBv yuwMHRryF5jCCJC0VUKTTy9btk4e9Cxq2j3rfUDgrsMQUvuwn1R+4hv8W24gug== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=none; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org"; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=gmail.com (policy=none) ARC-Seal: i=1; s=key1; d=yhetil.org; t=1675264642; a=rsa-sha256; cv=none; b=gSP2ReEPqzHvda/DygmYisZIqToOJilWHoJxPrZ7Pfv3HsIPVLkFsv5PkF6sg2Hugi3Mll +j5z5IUakz5BvLovvHFJSnxCFnHembXAF7iHZEnHv4TVtjn+m7nc9g0Wn5FO7Z1nRpnW5W QC3HsfsKSNPES5AkbuajbBdhGUkmB7vxKrRpIW3DxYeXuGhlra72cBObu1uWja8NpT+mOC vU6SY093KY2EkkS6RJVJKOhSblUF11BOEThlT8LiLHn3OPQFf4foCzIBFAv8OIRrrY+y3O SLbma9H7EGygnLI3f5uUFYPiIKvF+Ai3gvKQwxtdHn4r9EAef00cfK7ZVsKHjA== Authentication-Results: aspmx1.migadu.com; dkim=none; spf=pass (aspmx1.migadu.com: domain of "emacs-orgmode-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="emacs-orgmode-bounces+larch=yhetil.org@gnu.org"; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=gmail.com (policy=none) X-Migadu-Scanner: scn0.migadu.com X-Spam-Score: -1.28 X-Migadu-Queue-Id: 8CD3F6E0D X-Migadu-Spam-Score: -1.28 X-TUID: 2S0nEoDO+hfj On 01/02/2023 20:26, Ihor Radchenko wrote: > > There is potential confusion coming from the different interpretations > of the time zone offsets used in ISO8601 and POSIX TZ specs: Ihor, I am sorry that I did not reply to your early question. Is there a strong reason to support POSIX TZ? Time zones with fixed offsets are available as e.g. Etc/GMT-8 (unfortunately inverted sign as well). In a link posted in this thread I noticed the following: http://naggum.no/lugm-time.html Erik Naggum. The Long, Painful History of Time. 1999 > 8.2 Timezone Representation > > David Olsen of Digital Equipment Corporation has laid down a tremendous > amount of work in collecting the timezones of the world and their > daylight saving time boundaries. Contrary to the Unix System V approach > from New Jersey (insert appropriate booing for best effect), which > codifies a daylight saving time regime only for the current year, and > apply it to all years, David Olsen's approach is to maintain tables of > all the timezone changes. POSIX spec neglects history of changes. At certain moment Firefox used IANA TZ DB with accurate data while Chrome followed JavaScript spec that required POSIX-like approach for local time zone. The latter was pain. I consider POSIX TZ as legacy.