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Asked: 2026-05-23T03:04:17+00:00

http://doc.qt.io/qt-5/qdesktopwidget.html#obtaining-a-desktop-widget The QApplication::desktop() function is used to get an instance of QDesktopWidget. I don’t

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http://doc.qt.io/qt-5/qdesktopwidget.html#obtaining-a-desktop-widget

The QApplication::desktop() function is used to get an instance of QDesktopWidget.

I don’t understand why should you use QApplication::desktop(), when you can just directly call QDesktopWidget() class.
What is the difference between 

desktop = QApplication.desktop()

and

desktop = QDesktopWidget()

They look like the same. But Windows(OS) throws warning on exit when using QDesktopWidget(). So there should be some difference.

How they differs?

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1 Answer

  1. Editorial Team

    They may look the same but are not. On the C++ side the static desktop() function is using a singleton pattern – there is only one desktop and it is represented by a static variable, which may (or may not) be created on request. QDesktopWidget() is a constructor, which is not accessible for the “outside world” to guarantee the uniqueness of the singleton.

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