From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp-out-no.shaw.ca (smtp-out-no.shaw.ca [64.59.134.12]) by sourceware.org (Postfix) with ESMTPS id 5F57E388E820 for ; Wed, 9 Jun 2021 05:50:14 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 5F57E388E820 Authentication-Results: sourceware.org; dmarc=none (p=none dis=none) header.from=SystematicSw.ab.ca Authentication-Results: sourceware.org; spf=none smtp.mailfrom=systematicsw.ab.ca Received: from [192.168.1.104] ([68.147.0.90]) by shaw.ca with ESMTP id qr6SlGTgeycp5qr6Tl9Kdw; Tue, 08 Jun 2021 23:50:13 -0600 X-Authority-Analysis: v=2.4 cv=H864f8Ui c=1 sm=1 tr=0 ts=60c05695 a=T+ovY1NZ+FAi/xYICV7Bgg==:117 a=T+ovY1NZ+FAi/xYICV7Bgg==:17 a=IkcTkHD0fZMA:10 a=8AHkEIZyAAAA:8 a=w_pzkKWiAAAA:8 a=yMhMjlubAAAA:8 a=uZvujYp8AAAA:8 a=tbFE_IfxFiSdXi-lcTQA:9 a=QEXdDO2ut3YA:10 a=otTE43H4AhkA:10 a=AomDDAB-fV4A:10 a=sRI3_1zDfAgwuvI8zelB:22 a=SLzB8X_8jTLwj6mN0q5r:22 Reply-To: cygwin@cygwin.com To: cygwin@cygwin.com References: <5542c19d-8b1a-1f28-2003-fe9493ee9b56@mail.ru> <60BF5677.9060904@tlinx.org> <97024d79-16b2-98a0-d20a-b3e6915ad0d0@mail.ru> <60BF6ADB.304@tlinx.org> From: Brian Inglis Organization: Systematic Software Subject: Re: Python for Windows reports wrong local time when run under Cygwin on Europe/Moscow TZ Message-ID: <92dc21ea-0975-2c58-5c5c-f3d8962d34c6@SystematicSw.ab.ca> Date: Tue, 8 Jun 2021 23:50:12 -0600 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-CA Content-Transfer-Encoding: 8bit X-CMAE-Envelope: MS4xfIp/mfgndAw3+u28aI5goQPvE3nzD013/TGNirP8aTD4XLeU0Wr4pIpDzp8VbUgMgms0ccreLtzNLMPnvr1M7ocQZ1WSNlx3vfNaV4vfB2KLSPO3pFWP RKzkJtol9rNEpnTX6RCllxBnhLwxNtLNH6rJPaAVExe8U/6/5DJoNI67LBA0HtMXg7HTLUTevap+/sAxzbXYPKRExXWyCN4ezGU= X-Spam-Status: No, score=-3488.0 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS, KAM_LAZY_DOMAIN_SECURITY, NICE_REPLY_A, RCVD_IN_BARRACUDACENTRAL, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_NONE, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: cygwin@cygwin.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: General Cygwin discussions and problem reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 09 Jun 2021 05:50:17 -0000 On 2021-06-08 14:03, Mike Kaganski via Cygwin wrote: > On 08.06.2021 16:04, L A Walsh wrote: >> You might ask on a python list if anyone else has experienced >> something similar with python or any other program.  I'm fairly sure >> that neither MS nor cygwin design their OS with python in mind and >> that it is python that is interacting funny when running under some >> merge of both.  Have you asked the python people about this problem? >> What did they suggest? > > FTR: filed https://bugs.python.org/issue44352. See Keith Thompson subthread and my reply with suggested fix: https://cygwin.com/pipermail/cygwin/2021-June/248692.html Windows does not recognize zoneinfo time zone identifiers in TZ only base format POSIX TZ strings with three alphabetic character identifiers: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/tzset?view=msvc-160 That assumes US switch date "rules": for all years up to current, or just DST, and whether pre- or post-2007 is unstated! Otherwise it defaults to regional settings, used by Cygwin to map to zoneinfo time zone identifiers, so if Python for Windows could clear TZ before it is read by MSVCRT, it should DTRT. Windows does not recognize expanded POSIX TZ format strings with <> quoted alphanumeric characters, "-", "+", and start and end dates/times: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#bottom which make them usable outside of the US. -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in binary units and prefixes, physical quantities in SI.]