From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp12.migadu.com ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms5.migadu.com with LMTPS id 2AQ6EWd722MpSgEAbAwnHQ (envelope-from ) for ; Thu, 02 Feb 2023 09:59:19 +0100 Received: from aspmx1.migadu.com ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp12.migadu.com with LMTPS id iEkOEWd722NSmAAAauVa8A (envelope-from ) for ; Thu, 02 Feb 2023 09:59:19 +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 080022045E for ; Thu, 2 Feb 2023 09:59:18 +0100 (CET) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pNVQh-0000Md-Ue; Thu, 02 Feb 2023 03:58:51 -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 1pNVQg-0000MB-HN for emacs-orgmode@gnu.org; Thu, 02 Feb 2023 03:58:50 -0500 Received: from mout01.posteo.de ([185.67.36.65]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pNVQe-0002ji-FN for emacs-orgmode@gnu.org; Thu, 02 Feb 2023 03:58:49 -0500 Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 402CA2403F1 for ; Thu, 2 Feb 2023 09:58:46 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1675328326; bh=4mk1M5O4XpmTDNXoZBFbbQpMbWJpjYmyln+/h506Jlk=; h=From:To:Cc:Subject:Date:From; b=ZvC88BMlnq3SEJspt/JYpmQoZf3S0r6qyy+E8DkmWVLdVHzerV8SFLauL9TP40iLR ITZRkv47US6jYviLC/ibLep8LFSOKor7mwlvdwUF26qFEsiTR0JDVOnNyDN8k6oADF i3Y8fgXxrMPH0WBytGJMyncN/5XpASCK89UdBklh2WRUaSvxf9pQ+ojI5fhxpfQOsN XV/W0ZJVODh/bdRSWowymj2UgSru3xdM6QSLnVOhVpaOQRiTas/SnP4B4RFb84Qa5s 4LCCG4a0z60UTg4WqOcQbzslxVQV5sgkR2gxJqtklyEG2PfcNjAgQnbtd+ha/cPXem xjq/X1wViuztw== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4P6t4P1qW1z9rxK; Thu, 2 Feb 2023 09:58:45 +0100 (CET) From: Ihor Radchenko To: Max Nikulin Cc: emacs-orgmode@gnu.org Subject: Re: [POLL] Proposed syntax for timestamps with time zone info (was: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda) In-Reply-To: References: <87lelo8c9r.fsf@localhost> <2150768.1675077958@archlinux> <87tu063ox2.fsf@localhost> <87h6w63jgg.fsf@localhost> <86wn51g661.fsf@gmail.com> <87357pn57t.fsf@localhost> <86sffpg1bv.fsf@gmail.com> <87wn51ibcc.fsf@localhost> Date: Thu, 02 Feb 2023 08:59:22 +0000 Message-ID: <878rhgqw7p.fsf@localhost> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=185.67.36.65; envelope-from=yantar92@posteo.net; helo=mout01.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, 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=1675328359; a=rsa-sha256; cv=none; b=okV2oCb/MlKy/3x4w+HGtRtNfkshZiueL+r4CfTA9O9RfeHzEXHGYDlHvAAUWhPhhhJU/L MFfafyaLCM4B/2pc88RuOlxnmTXs56FN9Wr93w2a+l2ckee7tR5kH5RkObuzgb0H8at5U2 +eP+xAYaFQH5Mq/sAFEFQ8LDEvJtwG3fGCAGO+i/XgTnaKt0EHlaQ5E74rpFiRUtUARFLI UsLRvE5rbGde7q81WvHdVCc9fgOT0djt/5nLNCsyjxRe5NJX/bg6d0x0QtG3634I5hC12K 4NBnWhRmeHxS8X93E9u8+njKGk1TZiaoCrsu0ZDJaEpaMYr5nALOu3e5WCgFQw== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b=ZvC88BMl; 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=1675328359; 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=j0uUEYyjm8uebQF4WVHch1QtWba2o1zEe0HrbNj7d68=; b=oklh4fLguXtCPocHwWHLYAtrf3nVOILeFf0YeI0R4iqnqD1gKG/DnGQKdAdaWF/CqQvXvP /EkzGUROWRRDZ07z7QvaiESR27bRNfP5vdYwhjcw+RMMnDSyUjIp5Kp68lTaF0unwYLVcW FORGk6E3bcq9ikFxTitVJMWLxheinXxsyN88bFAx0nvwiv2dzTX4m6ZP19B9ZDFbxGyvA5 vF5EOZQ4txPMrmS1YnOdAlTpP55TIvITvEyls7+O9fLA5WNvrVCxT9QOnFQQONqXVBI2V1 NdwKBlxSflXaI6cQjVmaXfSsqqEntmT0OYWV+FzNXOUbGLNKsk5tLzcwRSVDMw== X-Migadu-Scanner: scn1.migadu.com X-Migadu-Spam-Score: -4.55 X-Spam-Score: -4.55 X-Migadu-Queue-Id: 080022045E Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=posteo.net header.s=2017 header.b=ZvC88BMl; 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: bdeXO2WPDAEH Max Nikulin writes: > On 01/02/2023 23:45, Ihor Radchenko wrote: >> >> Note how `encode-time' TIME argument has both DST flag and the time zone >> name: >> >> (SECOND MINUTE HOUR DAY MONTH YEAR IGNORED DST ZONE) >> >> DST is necessary exactly in the ambiguous situations like I described, >> when we must know if day saving time is in effect or not __in addition__ >> to time zone name. > > Warning: just be aware that sometimes DST is not enough to resolve > ambiguity. E.g. in the following example attempt to pass non-nil DST > signals an error: > > zdump -v Africa/Juba | grep 2021 > Africa/Juba Sun Jan 31 20:59:59 2021 UT = Sun Jan 31 23:59:59 2021 EAT > isdst=0 gmtoff=10800 > Africa/Juba Sun Jan 31 21:00:00 2021 UT = Sun Jan 31 23:00:00 2021 CAT > isdst=0 gmtoff=7200 Providing UTC offset will resolve the ambiguity in this scenario. So, we are good. Unfortunately, there seems to be no way to detect such ambiguities programmatically. Not using glibc, at least. -- Ihor Radchenko // yantar92, Org mode contributor, Learn more about Org mode at . Support Org development at , or support my work at