QT how to traverse under the first stage of a key file , for example, the first level traversal HKEY_USERS file , how to deal with it ? ? ?

I used QSetting found under childGroups and childKeys these two functions
QString dirPath = QString ("HKEY_USERS");
QSettings settings (dirPath, QSettings :: NativeFormat);
settings.beginGroup (dirPath);
QStringList keys = settings.childKeys ();
such , keys are not values ​​, how to deal with this , there are other ways . . . . .
you big ah God for guidance . . . . . .
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specific operations such platforms should be the first thought Windows API
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Thank you , the problem has been resolved