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 iB8+H5nD22ODDgAAbAwnHQ (envelope-from ) for ; Thu, 02 Feb 2023 15:07:21 +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 mHw7HpnD22N4+wAAG6o9tA (envelope-from ) for ; Thu, 02 Feb 2023 15:07:21 +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 1A74ED53D for ; Thu, 2 Feb 2023 15:07:20 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pNaEY-0003KG-Iu; Thu, 02 Feb 2023 09:06:38 -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 1pNaEX-0003K7-Le for emacs-orgmode@gnu.org; Thu, 02 Feb 2023 09:06:37 -0500 Received: from mout02.posteo.de ([185.67.36.66]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNaEV-00040t-Pz for emacs-orgmode@gnu.org; Thu, 02 Feb 2023 09:06:37 -0500 Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 55B9424050F for ; Thu, 2 Feb 2023 15:06:26 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1675346786; bh=zHWLv+54LDqB5tfuqfyusWHBGrbn875NQAd6fDx5LvM=; h=From:To:Cc:Subject:Date:From; b=I/EPhB1DgnAFkfuLLO4fj2gj8v98kZffr6OAn78wsp7J3Pc3z/QMBNpS1tK74e0mD FxIugcm3tO78GBlqm5nG2wtI0Lv10xiLy1Tu729PTUCNZcrssRbird0t/+EvR3Az5o 8qt4nRQlnkFIGbjapyTo7hPUu3nA2b2mqnYbzITtv+59M5HfpDZsfdY7tJ16hLhsRW tTQXUeYWbBkt2fTkYR0pkM3i6Tnnc4dWhvbNEHjfwXqyNjPrkAkNyfVeeMh+iV8LV4 //eZNoWKC26H17WNHfZU+kqLLVhu9GkzDPMDlV23+uvSuBu7l30fV9nDLktY2ZcCXT iO2yOAjR41ZfA== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4P70vL5p1Pz6tmh; Thu, 2 Feb 2023 15:06:22 +0100 (CET) From: Ihor Radchenko To: Max Nikulin Cc: emacs-orgmode@gnu.org 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) In-Reply-To: References: <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> <87h6w4qxcn.fsf@localhost> Date: Thu, 02 Feb 2023 14:06:59 +0000 Message-ID: <87y1pgnou4.fsf@localhost> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=185.67.36.66; envelope-from=yantar92@posteo.net; helo=mout02.posteo.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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-Seal: i=1; s=key1; d=yhetil.org; t=1675346841; a=rsa-sha256; cv=none; b=dk0vmbBkQW7E5Wn2+QzDjHhGow9O1it0kU2boTf5IGWxs/0cr+hptBofntZIU9ti2vDPjk dHIxe3XeJVUioaJDlbn0s77VTbYaKJR+P71Pm7XfuFHqa0t/dYvbs9OxMdQWWzm6Uoeg9P evl2GUtpRVViSlR0aD8D5cD5XiNix+MW1du48DrqPGi0Po5Rvbb6CS8AUJKBw6QkzHc1HO GsFHHlSgqp7lU+WcCsUF51q8nOw2zu8VNiehjQznpLxSb2nm2bGsHwPv66NaJOCN7vwQL7 hV4RM+BGtj5QH+ISBX2ddQ28hdNEnUdtkMTmaTQd513Ep9i2kQ2LRhjzm+UJYA== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b="I/EPhB1D"; 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=pass (policy=none) header.from=posteo.net ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1675346841; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references:list-id:list-help:list-unsubscribe: list-subscribe:list-post:dkim-signature; bh=jeBW2n9wjoRZegrhX7vEH/P56rPnKRkNdTU7UboIgrE=; b=gluZLBVA2G06UIcrVI3LcAGRRrNtoO4tp1kkT+XLFbiQPpRmprWk1pAxWzoyj/S/kDEeik bnq9BsYPUzazbeW/Ev5kHVcZUM8B1yBWTYfcr7F0+r13gHQdl3ICZETkyuNvNcNVgIxNIc pE5oeqOqiB8ZkwNQi3+Vb1rRXbM5gPzspN/PV+hOIHm+nRHVZ8M45Tvh80qiH8PamP6hve 7/qsC1YLJnj3JF3oLdGF5lo3hEN63kLZyY2XC9k/H+uj1lH9+KSyGVfQ175v5vJ8nxzFIT /qavfZxcOFiwLfnQX2Vxa/pX0viJKAIuMZEKmhZ/RAvaf0U2m4UdUPrWzf9Lhg== X-Migadu-Scanner: scn1.migadu.com X-Migadu-Spam-Score: -4.55 X-Spam-Score: -4.55 X-Migadu-Queue-Id: 1A74ED53D Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b="I/EPhB1D"; 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=pass (policy=none) header.from=posteo.net X-TUID: vqz++c1Jnie2 Max Nikulin writes: >> Because `encode-time' accepts POSIX TZ as argument. So, may as well. >> Note that Etc/GMT-8 is also accepted as POSIX TZ. > > "May" does not assume "should". It will be easier to implement POSIX TZ compared to limiting it to TZDB. We have no way to know if a given string is a valid TZDB entry to not. > The disappointing issue with POSIX syntax is the case of decision of > authorities to change time zone offset. It is neither regular DST rule > nor constant offset. The result is incorrect mapping between UTC and > local time. We cannot do much about it, AFAIU. Maximum is trying to do feature request in glibc, but I assume that they know about this issue. -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . Support Org development at , or support my work at