qt-When you click the Close button to indicate whether to exit

In programming, it is often necessary to pop up a dialog box when the window is closed, allowing the user to choose whether to exit. The implementation is simple and reproduces the closeevent function of the main window, which is called when the window is closed. You can pop up a dialog box prompt in the function.

void Clg::closeevent (qcloseevent *ev)
{
    if (clgmessagebox::warnning ("Exit", "Confirm exit". ", True,true) ==clgdialog::accepted)
        {
              ev->accept ();
        }
        else
        {
             ev->ignore ();
        }
    
}

After the user clicks OK, accepts the Shutdown event and the program exits.

Otherwise, the close event is ignored and the window does not exit.

The clgmessagebox here is the rewrite prompt dialog box, which can also be used with the system itself.