From b266263699ab1b02d7d4b7307e5303181bea00c1 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Thu, 7 Dec 2017 22:29:53 -0800 Subject: [PROPOSED] Ireland observes standard time in summer, not winter (Discrepancy noted by Derick Rethans.) * NEWS: Document this. * europe (Eire): New ruleset. (Europe/Dublin): Use it. * theory.html (Time zone abbreviations): Fix IST. --- NEWS | 11 +++++++++++ europe | 38 ++++++++++++++++++++++++++++++++------ theory.html | 3 ++- 3 files changed, 45 insertions(+), 7 deletions(-) diff --git a/NEWS b/NEWS index 239dd33..51786c6 100644 --- a/NEWS +++ b/NEWS @@ -13,6 +13,17 @@ Unreleased, experimental changes BST instead of BOST, to be more consistent with the convention used for Latvian Summer Time (1918-9) and for British Summer Time. + Changes to tm_isdst + + Change Europe/Dublin so that it observes Irish Standard Time (UT + +01) in summer and GMT (as negative daylight-saving) in winter, + instead of observing standard time (GMT) in winter and Irish + Summer Time (UT +01) in summer. This change does not affect UT + offsets or abbreviations; it affects only whether timestamps are + considered to be standard time or daylight-saving time, as + expressed in the tm_isdst flag of C's struct tm type. + (Discrepancy noted by Derick Rethans.) + Changes to build procedure The default installation procedure no longer creates the diff --git a/europe b/europe index 4409be3..0fd3cc2 100644 --- a/europe +++ b/europe @@ -68,6 +68,7 @@ # 0:00 WET WEST WEMT Western Europe # 0:19:32.13 AMT* NST* Amsterdam, Netherlands Summer (1835-1937) # 1:00 BST British Standard (1968-1971) +# 1:00 IST GMT Irish Standard (1968-) with winter DST # 1:00 CET CEST CEMT Central Europe # 1:00:14 SET Swedish (1879-1899) # 1:36:34 RMT* LST* Riga, Latvian Summer (1880-1926)* @@ -362,12 +363,28 @@ # regulations. I spoke this morning with the Secretary of the Department of # Justice (tel +353 1 678 9711) who confirmed to me that the correct name is # "Irish Summer Time", abbreviated to "IST". +# +# From Paul Eggert (2017-12-07): +# The 1996 anonymous contributor's goal was to determine the correct +# abbreviation for summer time in Dublin and so the contributor +# focused on the "IST", not on the "Irish Summer Time". Though the +# "IST" was correct, the "Irish Summer Time" appears to have been an +# error, as Ireland's Standard Time (Amendment) Act, 1971 states that +# standard time in Ireland remains at UT +01 and is observed in +# summer, and that Greenwich mean time is observd in winter. (Thanks +# to Derick Rethans for pointing out the error.) That is, when +# Ireland amended the 1968 act that established UT +01 as Irish +# Standard Time, it left standard time unchanged and established GMT +# as a negative daylight saving time in winter. So, in this database +# IST stands for Irish Summer Time for timestamps before 1968, and for +# Irish Standard Time after that. See: +# http://www.irishstatutebook.ie/eli/1971/act/17/enacted/en/print # Michael Deckers (2017-06-01) gave the following URLs for Ireland's # Summer Time Act, 1925 and Summer Time Orders, 1926 and 1947: -# http://www.irishstatutebook.ie/eli/1925/act/8/enacted/en/print.html -# http://www.irishstatutebook.ie/eli/1926/sro/919/made/en/print.html -# http://www.irishstatutebook.ie/eli/1947/sro/71/made/en/print.html +# http://www.irishstatutebook.ie/eli/1925/act/8/enacted/en/print +# http://www.irishstatutebook.ie/eli/1926/sro/919/made/en/print +# http://www.irishstatutebook.ie/eli/1947/sro/71/made/en/print # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S # Summer Time Act, 1916 @@ -491,6 +508,17 @@ Link Europe/London Europe/Jersey Link Europe/London Europe/Guernsey Link Europe/London Europe/Isle_of_Man +# The following is like GB-Eire and EU, except with standard time in +# summer and negative daylight saving time in winter. +# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S +Rule Eire 1971 only - Oct 31 2:00u -1:00 GMT +Rule Eire 1972 1980 - Mar Sun>=16 2:00u 0 IST +Rule Eire 1972 1980 - Oct Sun>=23 2:00u -1:00 GMT +Rule Eire 1981 max - Mar lastSun 1:00u 0 IST +Rule Eire 1981 1989 - Oct Sun>=23 1:00u -1:00 GMT +Rule Eire 1990 1995 - Oct Sun>=22 1:00u -1:00 GMT +Rule Eire 1996 max - Oct lastSun 1:00u -1:00 GMT + # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Europe/Dublin -0:25:00 - LMT 1880 Aug 2 -0:25:21 - DMT 1916 May 21 2:00s @@ -502,9 +530,7 @@ Zone Europe/Dublin -0:25:00 - LMT 1880 Aug 2 0:00 1:00 IST 1947 Nov 2 2:00s 0:00 - GMT 1948 Apr 18 2:00s 0:00 GB-Eire GMT/IST 1968 Oct 27 - 1:00 - IST 1971 Oct 31 2:00u - 0:00 GB-Eire GMT/IST 1996 - 0:00 EU GMT/IST + 1:00 Eire IST/GMT ############################################################################### diff --git a/theory.html b/theory.html index 8ea5771..dbc7660 100644 --- a/theory.html +++ b/theory.html @@ -330,6 +330,7 @@ GST Guam, HST/HDT Hawaii, HKT/HKST Hong Kong, IST India, +IST/GMT Irish, IST/IDT/IDDT Israel, JST/JDT Japan, KST/KDT Korea, @@ -387,7 +388,7 @@ TMT Tallinn, Tehran; WMT Warsaw.

A few abbreviations also follow the pattern that -GMT/BST/IST/BDST established for time in the UK. They are: +GMT/BST established for time in the UK. They are: CMT/BST for Calamarca Mean Time and Bolivian Summer Time 1890–1932, DMT/IST for Dublin/Dunsink Mean Time and Irish Summer Time -- 2.7.4