- tz - lists.iana.org

Namibia to change time zone/go permanent DST
by Steffen Thorsen Aug. 10, 2017

Aug. 10, 2017

Namibia is going to change their time zone to what is now their DST: https://www.newera.com.na/2017/02/23/namibias-winter-time-might-be-repealed/ This video is from the government decision: https://www.nbc.na/news/na-passes-namibia-time-bill-repealing-1994-namibia-… We have made the assumption so far that they will change their time zone at the same time they would normally start DST, the first Sunday in September: https://www.timeanddate.com/news/time/namibia-new-time-zone.html Best regards, Steffen

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Israel POSIX timezone string error on release 2017b?
by André Domingos Brízido Aug. 8, 2017

Aug. 8, 2017

Hello According to the Linux manual (http://man7.org/linux/man-pages/man5/tzfile.5.html) the last line of the time zone database may contain the POSIX timezone string, which is the case of the files generated by following the instructions in https://www.iana.org/time-zones/repository/tz-link.html I've downloaded the latest release (2017b) and I obtain the following POSIX string for Israel: [/usr/share/zoneinfo]# tail -n 1 Israel IST-2IDT,M3.4.4/26,M10.5.0 But if I understood correctly, the POSIX specification (http://pubs.opengroup.org/onlinepubs/9699919799/) states that the value '26' is out of range. It should be between zero and 24. My linux system does not display the correct timezone if I use the string 'IST-2IDT,M3.4.4/26,M10.5.0' as the contents of /etc/TZ. Best regards Andre Brizido

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[PROPOSED] Improve tzfile.5 formatting and clarity
by Paul Eggert Aug. 7, 2017

Aug. 7, 2017

* tzfile.5: Break out field descriptions into bulleted lists, to make them easier to follow. This does not change the technical content of the spec, just its presentation. --- tzfile.5 | 77 ++++++++++++++++++++++++++++++++++++++++------------------------ 1 file changed, 48 insertions(+), 29 deletions(-) diff --git a/tzfile.5 b/tzfile.5 index 52c5301..b7dc828 100644 --- a/tzfile.5 +++ b/tzfile.5 @@ -10,17 +10,29 @@ tzfile \- time zone information \\$3\*(lq\\$1\*(rq\\$2 .. The time zone information files used by -.IR tzset (3) -begin with the magic characters "TZif" to identify them as -time zone information files, -followed by a character identifying the version of the file's format -(as of 2013, either an ASCII NUL, or '2', or '3') -followed by fifteen bytes containing zeroes reserved for future use, -followed by six four-byte integer values +.BR tzset (3) +are typically found under a directory with a name like +.IR /usr/share/zoneinfo . +These files begin with a 44-byte header containing the following fields: +.IP * 2 +The magic four-byte ASCII sequence +.q "TZif" +identifies the file as a time zone information file. +.IP * +A byte identifying the version of the file's format +(as of 2017, either an ASCII NUL, or +.q "2", +or +.q "3" ). +.IP * +Fifteen bytes containing zeros reserved for future use. +.IP * +Six four-byte integer values written in a standard byte order (the high-order byte of the value is written first). These values are, in order: +.RS .TP .I tzh_ttisgmtcnt The number of UT/local indicators stored in the file. @@ -40,28 +52,30 @@ The number of local time types for which data entries are stored in the file (must not be zero). .TP .I tzh_charcnt -The number of characters of time zone abbreviation strings +The number of bytes of time zone abbreviation strings stored in the file. +.RE .PP -The above header is followed by +The above header is followed by the following fields, whose lengths +vary depend on the contents of the header: +.IP * 2 .I tzh_timecnt four-byte signed integer values sorted in ascending order. These values are written in standard byte order. Each is used as a transition time (as returned by -.IR time (2)) +.BR time (2)) at which the rules for computing local time change. -Next come +.IP * .I tzh_timecnt one-byte unsigned integer values; each one tells which of the different types of local time types described in the file is associated with the time period starting with the same-indexed transition time. -These values serve as indices into an array of -.I ttinfo -structures (with +These values serve as indices into the next field. +.IP * .I tzh_typecnt -entries) that appears next in the file; -these structures are defined as follows: +.I ttinfo +entries, each defined as follows: .in +.5i .sp .nf @@ -87,20 +101,19 @@ gives the number of seconds to be added to UT, tells whether .I tm_isdst should be set by -.I localtime (3) +.BR localtime (3) and .I tt_abbrind -serves as an index into the array of time zone abbreviation characters +serves as an index into the array of time zone abbreviation bytes that follow the .I ttinfo structure(s) in the file. -.PP -Then there are +.IP * .I tzh_leapcnt pairs of four-byte values, written in standard byte order; the first value of each pair gives the nonnegative time (as returned by -.IR time(2)) +.BR time (2)) at which a leap second occurs; the second gives the .I total @@ -109,16 +122,14 @@ starting at the given time. The pairs of values are sorted in ascending order by time. Each transition is for one leap second, either positive or negative; transitions always separated by at least 28 days minus 1 second. -.PP -Then there are +.IP * .I tzh_ttisstdcnt standard/wall indicators, each stored as a one-byte value; they tell whether the transition times associated with local time types were specified as standard time or wall clock time, and are used when a time zone file is used in handling POSIX-style time zone environment variables. -.PP -Finally there are +.IP * .I tzh_ttisgmtcnt UT/local indicators, each stored as a one-byte value; they tell whether the transition times associated with local time types @@ -126,7 +137,9 @@ were specified as UT or local time, and are used when a time zone file is used in handling POSIX-style time zone environment variables. .PP -.I Localtime +The +.BR localtime (3) +function uses the first standard-time .I ttinfo structure in the file @@ -137,11 +150,12 @@ if either .I tzh_timecnt is zero or the time argument is less than the first transition time recorded in the file. -.PP +.SS Version 2 format For version-2-format time zone files, the above header and data are followed by a second header and data, identical in format except that eight bytes are used for each transition time or leap second time. +(Leap second counts remain four bytes.) After the second header and data comes a newline-enclosed, POSIX-TZ-environment-variable-style string for use in handling instants after the last transition time stored in the file @@ -154,7 +168,7 @@ then if a last transition time is in July, the transition's local time type must specify a daylight-saving time abbreviated .q "WEST" that is one hour east of UT. -.PP +.SS Version 3 format For version-3-format time zone files, the POSIX-TZ-style string may use two minor extensions to the POSIX TZ format, as described in .IR newtzset (3). @@ -166,6 +180,11 @@ between daylight saving and standard time. .PP Future changes to the format may append more data. .SH SEE ALSO -newctime(3), newtzset(3), zdump(8), zic(8) +.BR time (2), +.BR localtime (3), +.BR tzset (3), +.BR tzselect (8), +.BR zdump (8), +.BR zic (8) .\" This file is in the public domain, so clarified as of .\" 1996-06-05 by Arthur David Olson. -- 2.7.4

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[PROPOSED] Minor tz-link updates.
by Paul Eggert Aug. 1, 2017

Aug. 1, 2017

* tz-link.htm: Add Noda Time updater. Add a downloading header, and simplify text editor discussion. --- tz-link.htm | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/tz-link.htm b/tz-link.htm index 803727b..589c781 100644 --- a/tz-link.htm +++ b/tz-link.htm @@ -10,7 +10,7 @@ content="Sources for time zone and daylight saving time data"> <meta name="DC.Creator" content="Eggert, Paul"> <meta name="DC.Contributor" content="Olson, Arthur David"> -<meta name="DC.Date" content="2017-07-08"> +<meta name="DC.Date" content="2017-08-01"> <meta name="DC.Description" content="Sources of information about time zones and daylight saving time"> <meta name="DC.Identifier" @@ -105,6 +105,7 @@ Universal Time</a> (<abbr>UTC</abbr>). The database also records when daylight saving time was in use, along with some time zone abbreviations such as <abbr>EST</abbr> for Eastern Standard Time in the <abbr>US</abbr>.</p> +<h2 id="download">Downloading the <code><abbr>tz</abbr></code> database</h2> <p> The following <a href="https://en.wikipedia.org/wiki/Unix_shell">shell</a> commands download @@ -196,9 +197,10 @@ title="International Components for Unicode">ICU</abbr></a>, <a href="https://developer.ibm.com/javasdk/support/dst/jtzu/"><abbr>IBM</abbr></a> and <a href="http://www.oracle.com/technetwork/java/javase/tzupdater-readme-136440.html">Oracle</a> -Java, <a href="http://www.joda.org/joda-time/tz_update.html">Joda-Time</a>, +Java, <a href="http://www.joda.org/joda-time/tz_update.html">Joda-Time</a>, <a +href="https://dev.mysql.com/doc/refman/en/time-zone-support.html">MySQL</a>, and <a -href="https://dev.mysql.com/doc/refman/en/time-zone-support.html">MySQL</a>. +href="http://nodatime.org/userguide/tzdb">Noda Time</a> (see below). </p> <p>Sources for the <code><abbr>tz</abbr></code> database are <a href="https://en.wikipedia.org/wiki/UTF-8"><abbr @@ -209,14 +211,11 @@ title="linefeed">LF</abbr></a>, which can be modified by common text editors such as <a href="https://www.gnu.org/software/emacs/">GNU Emacs</a>, <a href="https://wiki.gnome.org/Apps/Gedit">gedit</a>, and -<a href="http://www.vim.org">vim</a>. One -editor has a package to simplify editing further:</p> -<ul> -<li><a href="https://packagecontrol.io/packages/zoneinfo">Sublime -zoneinfo</a> is a <a href="http://www.sublimetext.com">Sublime -Text</a> package for syntax highlighting <code><abbr>tz</abbr></code> -source files.</li> -</ul> +<a href="http://www.vim.org">vim</a>. The <a +href="http://www.sublimetext.com">Sublime Text</a> editor has +a <a href="https://packagecontrol.io/packages/zoneinfo">Sublime +zoneinfo</a> package to simplify editing further. +</p> <p> For further information about updates, please see <a href="https://tools.ietf.org/html/rfc6557">Procedures for -- 2.7.4

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[PROPOSED] Detroit did not observe DST in 1967
by Paul Eggert July 27, 2017

July 27, 2017

* NEWS: Document this. * northamerica (Detroit): Remove bogus 1967 rules that were taken from Shanks. --- NEWS | 2 ++ northamerica | 15 +++++++++++++-- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/NEWS b/NEWS index 64d5c91..93633a5 100644 --- a/NEWS +++ b/NEWS @@ -4,6 +4,8 @@ Unreleased, experimental changes Changes to past time stamps + Detroit did not observe DST in 1967. + Use railway time for Asia/Kolkata before 1941, by switching to Madras local time (UT +052110) in 1870, then to IST (UT +0530) in 1906. Also, treat 1941-2's +0630 as DST, like 1942-5. diff --git a/northamerica b/northamerica index 651681d..b42aeb4 100644 --- a/northamerica +++ b/northamerica @@ -1040,12 +1040,23 @@ Zone America/Kentucky/Monticello -5:39:24 - LMT 1883 Nov 18 12:20:36 # one hour in 1914." This change is not in Shanks. We have no more # info, so omit this for now. # +# From Paul Eggert (2017-07-26): +# Although Shanks says Detroit observed DST in 1967 from 06-14 00:01 +# until 10-29 00:01, I now see multiple reports that this is incorrect. +# For example, according to a 50-year anniversary report about the 1967 +# Detroit riots and a major-league doubleheader on 1967-07-23, "By the time +# the last fly ball of the doubleheader settled into the glove of leftfielder +# Lenny Green, it was after 7 p.m. Detroit did not observe daylight saving +# time, so light was already starting to fail. Twilight was made even deeper +# by billowing columns of smoke that ascended in an unbroken wall north of the +# ballpark." See: Dow B. Detroit '67: As violence unfolded, Tigers played two +# at home vs. Yankees. Detroit Free Press 2017-07-23. +# http://www.freep.com/story/sports/mlb/tigers/2017/07/23/detroit-tigers-1967… +# # Most of Michigan observed DST from 1973 on, but was a bit late in 1975. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER Rule Detroit 1948 only - Apr lastSun 2:00 1:00 D Rule Detroit 1948 only - Sep lastSun 2:00 0 S -Rule Detroit 1967 only - Jun 14 2:00 1:00 D -Rule Detroit 1967 only - Oct lastSun 2:00 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone America/Detroit -5:32:11 - LMT 1905 -6:00 - CST 1915 May 15 2:00 -- 2.13.3

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Re: [tz] libc-2.25.90.pot
by Paul Eggert July 20, 2017

July 20, 2017

On 07/20/2017 07:57 AM, Siddhesh Poyarekar wrote: > Oh I meant PRIdLINENO, not PRIdMAX. I suppose using PRIdMAX directly > might work since gettext seems to recognize the other PRI* macros. Yes, PRIdMAX should work. The zic.c code uses the macro (as opposed to just %jd) to be portable to pre-C99 libraries. I installed the attached patch into the upstream tzdb sources; the zic.c part of it should work for glibc too. Thanks for reporting the problem.

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[PROPOSED] Use more up-to-date citation for leap seconds
by Paul Eggert July 18, 2017

July 18, 2017

* leapseconds.awk: Cite Levine 2016 instead of Quinn 1991. --- leapseconds.awk | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/leapseconds.awk b/leapseconds.awk index 405ce3a..66eb64d 100644 --- a/leapseconds.awk +++ b/leapseconds.awk @@ -17,11 +17,9 @@ BEGIN { print "# The International Earth Rotation and Reference Systems Service" print "# periodically uses leap seconds to keep UTC to within 0.9 s of UT1" print "# (which measures the true angular orientation of the earth in space); see" - print "# Terry J Quinn, The BIPM and the accurate measure of time," - print "# Proc IEEE 79, 7 (July 1991), 894-905 <http://dx.doi.org/10.1109/5.84965>," - print "# reprinted in: Hackman C, Sullivan DB (eds), Time and frequency measurement," - print "# American Association of Physics Teachers (1996)," - print "# <http://tf.nist.gov/general/pdf/1168.pdf>, 75-86." + print "# Levine J. Coordinated Universal Time and the leap second." + print "# URSI Radio Sci Bull. 2016;89(4):30-6. doi:10.23919/URSIRSB.2016.7909995" + print "# http://ieeexplore.ieee.org/document/7909995/" print "# There were no leap seconds before 1972, because the official mechanism" print "# accounting for the discrepancy between atomic time and the earth's rotation" print "# did not exist until the early 1970s." -- 2.7.4

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Pedantic correction to Theory regarding size of time zone names
by Howard Hinnant July 16, 2017

July 16, 2017

Line 91 of Theory: https://github.com/eggert/tz/blob/master/Theory#L91 reads: > A file name component must not exceed 14 characters … I found one exception to this rule: The Link: Canada/East-Saskatchewan in backward. East-Saskatchewan is 17 characters. I recommend simply changing the 14 to 17. Howard

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Unix time_t hits 1.5Gs early Friday UTC
by Brian Inglis July 14, 2017

July 14, 2017

Unix time_t will hit 1 500 000 000 at 2017 Jul 14 Fri 02:40:00+0000 which is Thursday evening in North America: $ for city in Vancouver Edmonton Regina Winnipeg Toronto Halifax St_Johns; do TZ=America/$city date -d@1500000000 +%c\ %Z; done 2017 Jul 13 Thu 19:40:00 PDT 2017 Jul 13 Thu 20:40:00 MDT 2017 Jul 13 Thu 20:40:00 CST 2017 Jul 13 Thu 21:40:00 CDT 2017 Jul 13 Thu 22:40:00 EDT 2017 Jul 13 Thu 23:40:00 ADT 2017 Jul 14 Fri 00:10:00 NDT and on some other time scales, which may not be aligned to UTC: $ gpstime.sh @1500000000 2017 Jul 14 Fri 02:40:00+0000 JD 2457948.611111 MJD 57948.111111 ToD 9599 NTP 3708988800 Unix 1500000000 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 1957 Cy 1 Wn 933 Wa 165 ToW 441618 DoW 5 ToD 9618 As usual there will be some Europeans staying up late to celebrate and party. Unix time won't hit 1.5Gis until: $ gpstime.sh @`bc <<< 2^30*3/2` 2021 Jan 14 Thu 08:25:36+0000 JD 2459228.851111 MJD 59228.351111 ToD 30336 NTP 3819601536 Unix 1610612736 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 2140 Cy 2 Wn 92 Wa 92 ToW 375954 DoW 4 ToD 30354 and it will be a while before it hits 2Gs: $ gpstime.sh @2000000000 2033 May 18 Wed 03:33:20+0000 JD 2463735.648148 MJD 63735.148148 ToD 12799 NTP 4208988800 Unix 2000000000 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 2784 Cy 2 Wn 736 Wa 224 ToW 272018 DoW 3 ToD 12818 -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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Use GST abbreviation for Asia/Dubai, Asia/Muscat
by Mohamed Akram July 14, 2017

July 14, 2017

I noticed Asia/Dubai and Asia/Muscat currently use +04, but there is an existing abbreviation (GST - Gulf Standard Time).

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