signals when closing QMainWindow

[nikhilqt]

One solution for what you want is,

Make the window/widget to modality, such that users cannot able to close the mainwindow until you close the other.

Check Qt::WindowModality.

And also,
I have implemented in my application, when you hit,

1. double click the upper-left corner of a QMainWindow, or
2. left click the upper-left corner of a QMainWindow, then select Close()

It calls closeEvent(...). you need to relook into its implementation.