How to do Qt UI in a DLL used by Qt / Non-QT apps

[cboles]

I am creating a DLL (and perhaps a dylib for OSX) that interfaces to some hardware that for the most part has no UI at all. If the DLL detects that the hardware's firmware is out of date, I want it to be able to pop up some simple message boxes to get the user's approval to update the firmware.

So for my DLL to do this via Qt, it needs to have a QApplication and a QApplication::exec() loop running right? The problem is, the hosting app may be:

(1) A Qt based application already running its own QApplication loop - how would I detect and use this?

(2) A non-Qt application running its own message loop of some form. How do I join this message loop? Or can I just start my own QApplication loop in another thread?

(3) A non-Qt application with no message loop (e.g. a console app). Is it possible for my DLL to start a GUI from inside a console app?

Thanks,

Colby