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Dye" To: Jean Louis Cc: Tim Cross , Sterling Hooten , "Thomas S. Dye" , Ihor Radchenko , Daryl Manning , rjhorn@alum.mit.edu, emacs-orgmode@gnu.org Subject: Re: [FEATURE REQUEST] Timezone support in org-mode datestamps and org-agenda Date: Sat, 28 Jan 2023 20:21:48 -1000 In-reply-to: Message-ID: <871qnd979o.fsf@tsdye.online> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - box2035.bluehost.com X-AntiAbuse: Original Domain - gnu.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - tsdye.online X-BWhitelist: no X-Source-IP: 50.113.33.148 X-Source-L: No X-Exim-ID: 1pM1It-000ssN-7O X-Source: X-Source-Args: X-Source-Dir: X-Source-Sender: cpe-50-113-33-148.hawaii.res.rr.com (poto-foou.tsdye.online) [50.113.33.148]:50146 X-Source-Auth: tsd@tsdye.online X-Email-Count: 7 X-Source-Cap: dHNkeWVvbmw7dHNkeWVvbmw7Ym94MjAzNS5ibHVlaG9zdC5jb20= X-Local-Domain: yes Received-SPF: pass client-ip=67.222.38.55; envelope-from=tsd@tsdye.online; helo=progateway7-pub.mail.pro1.eigbox.com X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 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, FROM_SUSPICIOUS_NTLD=0.499, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001, T_PDS_OTHER_BAD_TLD=0.01, T_SPF_HELO_TEMPERROR=0.01 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=1674974271; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post:dkim-signature; bh=+9iwBuvliHk7H02UrNGv/QzmXaXNhUTwhFBTxCqotCM=; b=LnVB+CnaS+fupY522l5oyccBb/6uqn+5ihjQzkq0DCDhrZjLHCA9ogeoeJnZU3ZBTwDxNC ujgZXjrK+dTEyIru8ZDFfzshL34zkgECbctmbi9uTv+Ob17qeLHVQIY0MizICa3uqDwzZn P9zM5lP9gm5QOcpAW/kNxM60S2tuWOsmkyBWXlHmk7qy4kHT1VD3rsDRFyHJB0ok8mZ/46 LJviAnVIfBy2soQDZq2Dmw1AlgPprviJVY8qpqMKxaUHSfnH7gxqcEU7XVR3vOTB+CUlaQ J8k0D71LuqB41hU7S0FFTgaVbmyeeXciHZwoS2FNGChy9dTrd6C9SP9l4Ycouw== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=tsdye.online header.s=default header.b=wecppa2P; dmarc=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" ARC-Seal: i=1; s=key1; d=yhetil.org; t=1674974271; a=rsa-sha256; cv=none; b=hEG0qFy/0CPYOP84AZcZ65TRbebCNilCxWf9JE8Ta461xTLSPJBhhiKJ8fQY3PwbMcald8 6x0XRMiJv110chTysxf4Ins5nLq8ZGYkycY/xJpsGi7Rao5pXMJ9q/H48f5mUoYbzcJvKB mYlxT1NBagLTIRnSHg2pidIo2y0/DB51kZgqWLbzhWvxdfSAVNuwr1r+ZQPyBJF7wwieIO 9RDOe9GrVxeDM/CGjreFF6xzl6fuadEQ24TsV09H5e05lfqv5TYEGNqGL2LAmeYyxJcOK6 jXBCeYbZmYgQF4rzhPPg6Jh1zAZJdX/YMi/smytDLmwPcqMcbTXrZ4s5O5NAvQ== Authentication-Results: aspmx1.migadu.com; dkim=fail ("headers rsa verify failed") header.d=tsdye.online header.s=default header.b=wecppa2P; dmarc=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" X-Migadu-Scanner: scn0.migadu.com X-Migadu-Spam-Score: -3.17 X-Spam-Score: -3.17 X-Migadu-Queue-Id: AE33615705 X-TUID: PbS+UrLF9uXY Jean Louis writes: > Time offset does not independently exists without time zone.=20 > While you > represent it without time zone, you have to observe time zone=20 > first, > before deriving time offset from it. > UTC offset exists without time zone. UTC is absolute time and=20 offsets from it do not refer to political time in a time zone.=20 They refer to local *solar time* at a particular place.=20=20 > Read from: > https://en.wikipedia.org/wiki/UTC_offset > > ,---- > | Daylight saving time > |=20 > | Several regions of the world use daylight saving time (DST)=20 > and the > | UTC offset during this season is typically obtained by adding=20 > one hour > | to local standard time. Central European Time UTC+01:00 is=20 > replaced by > | Central European Summer Time UTC+02:00, and Pacific Standard=20 > Time > | UTC=E2=88=9208:00 is replaced by Pacific Daylight Time UTC=E2=88=9207:0= 0. > `---- Your wikipedia citation puts it like this: "The UTC offset (or=20 time offset) is an amount of time subtracted from or added to=20 Coordinated Universal Time (UTC) time to specify the local solar=20 time (which may not be the current civil time, whether it is=20 standard time or daylight saving time)." Note that the quote distinguishes UTC offset from standard time=20 and daylight saving time, which refer to time zones. This distinction between absolute time (solar time) and space/time=20 (time zone) is fundamental. Confusing them leads to no good. hth, Tom --=20 Thomas S. Dye https://tsdye.online/tsdye