QScreen orientation

I run the program
output Qt::ScreenOrientation(LandscapeOrientation) QSize(1920, 1200)
I execute > xrandr -o 1
output Qt::ScreenOrientation(LandscapeOrientation) QSize(1200, 1920)
I quit the program

I execute > xrandr -o 1
I run the program
output Qt::ScreenOrientation(PortraitOrientation) QSize(1200, 1920)
I execute > xrandr -o 0
output Qt::ScreenOrientation(PortraitOrientation) QSize(1920, 1200)
I quit the program

QT       += core gui widgets
TARGET = untitled
TEMPLATE = app
SOURCES += main.cpp

#include <QApplication>
#include <QWidget>
#include <QScreen>
#include <QDebug>

class Widget : public QWidget
{
public:
  Widget()
  {
    m_s = QApplication::screens().first();
    startTimer(1000);
  }

private:
  void timerEvent(QTimerEvent*)
  {
    qDebug() << m_s->orientation() << m_s->size();
  }

QScreen* m_s;

};

int main(int argc, char *argv[]) {
  QApplication a(argc, argv);
  Widget w;
  w.show();
  return a.exec();
}