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| author | Edward Welbourne <edward.welbourne@qt.io> | 2022-02-17 16:28:57 +0100 |
|---|---|---|
| committer | Edward Welbourne <edward.welbourne@qt.io> | 2022-03-22 16:12:36 +0100 |
| commit | 37b0f2003c482a1f64c895efab1522bbb30de746 (patch) | |
| tree | d6283e00dfd8e710a22692e526593d32f50352fa | |
| parent | 2905cb06ccbf91623d46661989935e934362b840 (diff) | |
Update QTimeZone documentation on the limitations of MS's data
Describe the work-around of ignoring claims of DST prior to 1900.
Change-Id: Ia8a2e6530b285cc8012423ba174fea47732e9ecb
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Jaishree Vyas <jaishree.vyas@qt.io>
(cherry picked from commit bc91be6a5f57ec61287a0cc83e1264417448e74a)
| -rw-r--r-- | src/corelib/time/qtimezone.cpp | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/corelib/time/qtimezone.cpp b/src/corelib/time/qtimezone.cpp index 2d892fb924..cabbbad3b5 100644 --- a/src/corelib/time/qtimezone.cpp +++ b/src/corelib/time/qtimezone.cpp @@ -169,8 +169,11 @@ Q_GLOBAL_STATIC(QTimeZoneSingleton, global_tz); Windows native time zone support is severely limited compared to the standard IANA TZ Database. Windows time zones cover larger geographic areas and are thus less accurate in their conversions. They also do not - support as much historic conversion data and so may only be accurate for - the current year. + support as much historical data and so may only be accurate for the + current year. In particular, when MS's zone data claims that DST was + observed prior to 1900 (this is historically known to be untrue), the + claim is ignored and the standard time (allegedly) in force in 1900 is + taken to have always been in effect. QTimeZone uses a conversion table derived from the Unicode CLDR data to map between IANA IDs and Windows IDs. Depending on your version of Windows |