Expose a changing pointer from code

[gregersn]

I have in a headerfile
extern MyObject *pg;

and in a cpp-file
MyObject *pg;

the pointer initially a nullptr, that is changed by other functions in my librar.

With SIP I could just do MyObject *pg; in a file to expose that pointer to Python, and it would point to the right object and could be reached from Python code.

I am trying to achieve this with Pybind11.

I can do m.def("pg", []() { return Pyro::pg; }, py::return_value_policy::reference); which works, but I need to call a function from Python to get the pointer.
However, doing m.attr("pg") = Pyro::pg; always gives med None.

Are there any good suggestions or a solution for this? Having to call a function is a workaround, but I would like to avoid it.
I have tried looking in the documentation, but I might lack the terms I am looking for.