python embedding in C++ with functions returning shared_ptr(pybind11/boost_python)

Question

I am currently working on a usecase where I have implemented APIs in python and they need to return struct, vector and map to C++ caller functions. Could you please help me with an example how to do that. All the usecases I see in pybind/boost python is just simply python being embedded in C++ without any return value. I came across your blog as well that explained the two libraries pretty well. But I could not proceed because of this usecase. The scenario which I need to implement is a python -> C++ interface where the C++ caller will start a session and call various python objects when it wants and then close the session. I am ok with solution both in boost::python or pybind11

Answer 1

"All the usecases I see in pybind/boost python is just simply python being embedded in C++ without any return value."

PyBind11 Example with return value

The example the called python function returns an int which they assign first to a py::object and then cast to an int. For STL containers like std::map, std::vector there is automatic conversion if you #include <pybind11/stl.h> . I am unsure about conversion to struct, but I would use one of PyBind's built in STL conversions between Python and C++ and then construct the struct on the C++ side.