how to emit signal in a static function ?

[wysota]

OK let me explain what cxl2253 is trying to do?

Assume that you have a C library.
In the library's documentation you have a callback function about the progress of some event. So when this callback is called then cxl2253 want to emit a signal for passing info to related object.

We know that. But it's not mentioned anywhere that you should install callbacks on Qt objects. You should always think twice before mixing two technologies that use completely different approaches.

Assume that you want to wrap a class to convert C library to C++ object. As used library's docs says you need to use a callback func, but callbacks are not encouraged in C++ so what else to do?

<flamemode>Use another library?</flamemode>
Seriously - in such situations don't wrap the functions into classes. If you need callbacks - go ahead, create callback functions that will call regular methods from regular (maybe global?) objects. Then the objects can emit signals properly.