You mean stuff like the "signal" and "slot" declarations in the class definition? Wouldn't these types of classes be tied to the GUI framework anyway due to th

You mean stuff like the "signal" and "slot" declarations in the class definition? Wouldn't these types of classes be tied to the GUI framework anyway due to the inherited classes, implemented virtual functions, widget classes referenced and so forth? In my experience (having used Qt, GTK, FOX, FLTK and wxWidgets over the years), different GUI frameworks are significantly different in their APIs and how they work, to the point where I think changing existing code from any of these to any other is a very difficult job, with or without moc.