QDateTime to FILETIME

Question

I need to pass a QDateTime to a Win32 function that accepts FILETIME.

This is MSDN's definition of FILETIME:

Contains a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC).

Answer 1

I made a function to do that, which I've tested and it works:

// Convert a QDateTime to a FILETIME.
FILETIME toWinFileTime(const QDateTime &dateTime)
{
    // Definition of FILETIME from MSDN:
    // Contains a 64-bit value representing the number of 100-nanosecond intervals since January 1, 1601 (UTC).
    QDateTime origin(QDate(1601, 1, 1), QTime(0, 0, 0, 0), Qt::UTC);
    // Get offset - note we need 100-nanosecond intervals, hence we multiply by
    // 10000.
    qint64 _100nanosecs = 10000 * origin.msecsTo(dateTime);
    // Pack _100nanosecs into the structure.
    FILETIME fileTime;
    fileTime.dwLowDateTime = _100nanosecs;
    fileTime.dwHighDateTime = (_100nanosecs >> 32);
    return fileTime;
}