- tz - lists.iana.org

FW: Beginner's help request
by Daniel Ford Nov. 25, 2017

Nov. 25, 2017

Oops, looks like I was mistaken. Howard's library appears to be not (specifically) for Arduino, but a C++ library for Windows (and maybe other) platforms. Maybe it will compile in the Arduino IDE, though I suspect it will be problematic, if possible at all. And I've so far found only one TZdb mirror that keeps a current copy of the data - very disappointing. It's a shame the whole TZdb scheme is so user-unfriendly. Quite discouraging. Regards, Daniel -----Original Message----- From: Daniel Ford [mailto:dfnojunk@gmail.com] Sent: Saturday, November 04, 2017 7:03 PM To: 'Time zone mailing list' Subject: RE: [tz] Beginner's help request Woohoo! I've discovered (and downloaded) an Arduino library, written by Howard E. Hinnant: "This timezone library is a complete parser of the IANA timezone database. It provides for an easy way to access all of the data in this database, using the types from "date.h" and <chrono>. The IANA database also includes data on leap seconds, and this library provides utilities to compute with that information as well." All I need to find now are established TZdb mirrors that keep their copy up-to-date, so I don't overload the master TZdb with queries. Can anyone point me to any, please? Regards, Daniel --------------- Daniel Ford (Gerroa, Australia)

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Beginner's help request
by Daniel Ford Nov. 21, 2017

Nov. 21, 2017

I'm looking to develop a 'world clock' that could be sold to anyone (with Internet access via a Wi-Fi AP) anywhere in the world, that will display their local time, taking into account DST if/when applicable. Given that DST 'rules' can change at the whim of governments, my firmware will need to annually look up 'current' DST rules from the web. After much searching, it seems that your TZ Database is the best supported such reference for time zone rules. But I'm having great difficulty working out how I might access its mine of information... (I'll understand if you don't have time to help out a beginner, and maybe then you could refer me to a help site for TZ database applications.) I'm a hardware engineer with some programming experience, particularly assembler (various MCUs) and some C, but little or no experience in other languages. I'm developing this clock on an Arduino-like platform (NodeMCU, which has in-built Wi-Fi). My development tools run on a Win7Pro64 PC. The tools that you kindly provide for your database appear to be geared primarily towards Linux/Unix platforms, and I have no idea how I might convert them for a NodeMCU! I'm looking for some 'simple' way to access the desired TZ/DST information, preferably using simple string searches. For my application, all I'm interested in are the *current* rules. The wealth of history in your db is undoubtedly of interest to many, but for me is just 'clutter' to be searched through. But writing a program to find those rules for a particular locality has me stumped right now. I can't expect my dumb users to know a letter code for their time-zone/DST-rules, so all I'm expecting them to select from program-generated lists are: (1) their world region (Europe, Asia, Australasia, etc), and (2) the name of a major city in their time-zone with the same DST rules they follow. Let's take a concrete example: say my user has nominated 'Australasia' and 'Hobart'. So I look in your Australasia file and do a (manual at this stage) search for 'Hobart', but find only one reference to it (other than in comments). The jumble of numbers and letters there do not (clearly) tell me when DTS starts or ends. So how could I possibly write some code to find out that required information?? I've looked through the TZ_database-2017b.tar file for some sort of 'how-to' explanation of what all the file contents mean and how to programmatically search for a specific TZ, but have so far found nothing. Ideally, what I'd like to see is a text-only table of just current TZ/DST rules for each region/locality (they could all fit into a single file with all the historical data and comments removed), perhaps in the clear form used by Jack Christensen in his excellent Arduino Timezone library examples, such as... // Australia Eastern Time Zone (Sydney, Melbourne, Hobart) TimeChangeRule aEDT = {"AEDT", First, Sun, Oct, 2, 660}; TimeChangeRule aEST = {"AEST", First, Sun, Apr, 3, 600}; TimezoneExt ausET("NSW, Vic, Tas", aEDT, aEST); // Australia Eastern Time Zone (Brisbane) TimezoneExt QldT("Queensland", aEST, aEST); // no DST in Qld! ... which clearly tells me in a program-searchable way that in the main eastern states DST starts on the first Sunday in October at 2am, becoming UTC offset +11 hours (660 minutes), and ends on the first Sunday in April at 3am, reverting to UTC offset +10 hours. Couldn't be simpler! Any help in using the TZ database will be much appreciated (and acknowledged in my source code). Regards, Daniel --------------- Daniel Ford (Gerroa, Australia) "My loathings are simple: stupidity, oppression, crime, cruelty, soft music." - Vladimir Nabokov

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[PROPOSED] Update TZDIST citation.
by Paul Eggert Nov. 21, 2017

Nov. 21, 2017

* tz-link.htm: Update TZDIST URL and discussion. (Thanks to Ken Murchison for the heads-up.) --- tz-link.htm | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tz-link.htm b/tz-link.htm index 0684ed1..edf8eec 100644 --- a/tz-link.htm +++ b/tz-link.htm @@ -267,10 +267,10 @@ href="https://tools.ietf.org/html/rfc7808">TZDIST</a> (Internet <abbr>RFC</abbr> 7808), a time zone data distribution service, along with <a href="https://tools.ietf.org/html/rfc7809">CalDAV</a> (Internet <abbr>RFC</abbr> 7809), a calendar access protocol for -transferring time zone data by reference. The (expired) draft <a +transferring time zone data by reference. The draft <a id="TZDIST-Geolocate" -href="https://tools.ietf.org/html/draft-murchison-tzdist-geolocate-00">TZDIST -Geolocate Extension</a> would have let a client determine its time zone region +href="https://tools.ietf.org/html/draft-murchison-tzdist-geolocate-01">TZDIST +Geolocate Extension</a> lets a client determine its time zone region from its geographic location using a <a href="https://tools.ietf.org/html/rfc5870">'geo' URI</a>.</li> <li>The <a href="https://tools.ietf.org/html/rfc5545"> -- 2.7.4

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[PROPOSED] * tz-link.htm: Improve citations to ISO standards.
by Paul Eggert Nov. 21, 2017

Nov. 21, 2017

--- tz-link.htm | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/tz-link.htm b/tz-link.htm index 93bcbae..0684ed1 100644 --- a/tz-link.htm +++ b/tz-link.htm @@ -318,8 +318,11 @@ Database Parser</a> is a <a href="https://en.wikipedia.org/wiki/C%2B%2B">C++</a> parser and runtime library that is <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0355r4.html">moving -forward</a> for inclusion in the <a -href="https://isocpp.org/std/the-standard">ISO C++ standard</a>. +forward</a> for inclusion in the next iteration of <a +href="https://isocpp.org/std/the-standard"><abbr +title="International Organization for Standardization">ISO</abbr> +International Standard ISO/IEC 14882:2017(E) – Programming +Language C++</a>. It is freely available under the <abbr title="Massachusetts Institute of Technology">MIT</abbr> license.</li> <li><a id="ICU" href="http://site.icu-project.org">International Components for @@ -862,10 +865,9 @@ both <abbr title="Locale Data Markup Language">LDML</abbr> the international standard date and time notation</a> is a good summary of <a -href="https://www.iso.org/standard/40874.html"><abbr -title="International Organization for Standardization">ISO</abbr> +href="https://www.iso.org/standard/40874.html"><abbr>ISO</abbr> 8601:2004 – Data elements and interchange formats – Information -interchange – Representation of dates and times</a>.</li> +interchange – Representation of dates and times</a>.</li> <li> <a href="https://www.w3.org/TR/xmlschema-2/#dateTime"><abbr>XML</abbr> Schema: Datatypes – dateTime</a> specifies a format inspired by -- 2.7.4

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Earth rotation
by Arthur David Olson Nov. 19, 2017

Nov. 19, 2017

Seems there's a correlation between leap seconds and earthquakes. "Upsurge in big earthquakes predicted for 2018 as Earth rotation slows." https://www.theguardian.com/world/2017/nov/18/2018-set-to-be-year-of-big-ea… @dashdashado

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IANA and Microsoft mentioned in Wired article
by Matt Johnson Nov. 15, 2017

Nov. 15, 2017

A college of mine from the Windows time zone servicing team was recently interviewed for Wired magazine. https://www.wired.com/story/microsoft-time-lords/ I was happy to see the reporter included details about the critical contributions that the IANA TZDB brings to the table as well. Thanks everyone! Matt Johnson (Microsoft)

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Please include Montreal
by Sébastien Bouchard Nov. 14, 2017

Nov. 14, 2017

It would be nice if Montreal was included in your database. There are smaller cities that are listed. I am using the latest Linux Mint Mate (18.2) and i had to choose Toronto to get into the right timezone. Montreal is not there. It doesn't matter much to me but there are some people here who will find it strange. Toronto is like... in another country. It's about History and the French people in Canada... [1492899431935_logo3-rouge+gris-Sb=64px.png] <https://sites.google.com/view/sb-junior/> sites.google.com/ <https://sites.google.com/view/sb-junior/>view/sb-junior/<https://sites.google.com/view/sb-junior/><https://sites.google.com/view/sb-junior/><https://sites.google.com/view/sb-junior/>

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tzfile(5)
by Ken Murchison Nov. 13, 2017

Nov. 13, 2017

All, Is https://github.com/eggert/tz/blob/master/tzfile.5 the normative reference for the binary format of tzdata? I thinking about writing an I-D to register application/tzfile as a MIME type for use with TZDist <https://tools.ietf.org/html/rfc7808> and I obviously need a reference to the file format. Or should I document the format in the draft? Does anyone want to suggest a different name for the format? -- Kenneth Murchison Cyrus Development Team FastMail Pty Ltd

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draft-murchison-tzdist-geolocate-01
by Ken Murchison Nov. 13, 2017

Nov. 13, 2017

All, I'd appreciate any and all comments on this updated draft. I have a working implementation that I can probably put on an externally facing server if folks are interested. https://tools.ietf.org/html/draft-murchison-tzdist-geolocate-01 -- Kenneth Murchison Cyrus Development Team FastMail Pty Ltd

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[PROPOSED] * tz-link.htm: Improve citations to ISO standards.
by Paul Eggert Nov. 13, 2017

Nov. 13, 2017

--- tz-link.htm | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/tz-link.htm b/tz-link.htm index 93bcbae..0684ed1 100644 --- a/tz-link.htm +++ b/tz-link.htm @@ -318,8 +318,11 @@ Database Parser</a> is a <a href="https://en.wikipedia.org/wiki/C%2B%2B">C++</a> parser and runtime library that is <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0355r4.html">moving -forward</a> for inclusion in the <a -href="https://isocpp.org/std/the-standard">ISO C++ standard</a>. +forward</a> for inclusion in the next iteration of <a +href="https://isocpp.org/std/the-standard"><abbr +title="International Organization for Standardization">ISO</abbr> +International Standard ISO/IEC 14882:2017(E) – Programming +Language C++</a>. It is freely available under the <abbr title="Massachusetts Institute of Technology">MIT</abbr> license.</li> <li><a id="ICU" href="http://site.icu-project.org">International Components for @@ -862,10 +865,9 @@ both <abbr title="Locale Data Markup Language">LDML</abbr> the international standard date and time notation</a> is a good summary of <a -href="https://www.iso.org/standard/40874.html"><abbr -title="International Organization for Standardization">ISO</abbr> +href="https://www.iso.org/standard/40874.html"><abbr>ISO</abbr> 8601:2004 – Data elements and interchange formats – Information -interchange – Representation of dates and times</a>.</li> +interchange – Representation of dates and times</a>.</li> <li> <a href="https://www.w3.org/TR/xmlschema-2/#dateTime"><abbr>XML</abbr> Schema: Datatypes – dateTime</a> specifies a format inspired by -- 2.7.4

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