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Bug
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    Resolution: Duplicate
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P3: Somewhat important
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    None
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    5.4.1, 5.4.2
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    None
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    Qt 5.4.1, Windows 8 64bit, MinGW 32bit, MSVC2013 32bit, MSVC2013 64bit
 
Here is sample code for a bug reproduction:
#include <QCoreApplication>
#include <QDateTime>
#include <QTimeZone>
#include <iostream>
static void printQdt(const QDateTime &qdt)
{
    std::cout << qdt.toString("yyyy-MM-dd HH-mm-ss.zzz t").toStdString()
              << ", offsetFromUtc: "
              << qdt.offsetFromUtc()
              << std::endl;
}
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    QDateTime point(QDate(2015, 5, 27),
                    QTime(16, 37, 00),
                    QTimeZone("Europe/Moscow"));
    printQdt(point);
    printQdt(point.toUTC());
    return a.exec();
}
In a GNU/Linux environment output is following (i.e. a datetime representation converted to UTC as expected):
2015-05-27 16-37-00.000 MSK, offsetFromUtc: 10800 2015-05-27 13-37-00.000 UTC, offsetFromUtc: 0
In a Windows 8 environment output is following (i.e. UTC conversion failed, although time zone itself looks correct):
2015-05-27 16-37-00.000 RTZ 2 (winter), offsetFromUtc: 0 2015-05-27 16-37-00.000 UTC, offsetFromUtc: 0
Once you change time to another one (for example, "Europe/Paris") then it works as expected in both cases.
- duplicates
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QTBUG-42021 Incorrect calculation of next/previous transition in time zone on Windows
-         
 - Closed
 
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- relates to
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QTBUG-46455 Time is incorrect for a given milliseconds since epoch under Moscow's timezone
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 - Closed
 
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