Python embedded in CPP: how to get data back to CPP

Question

While working on a C++ project, I was looking for a third party library for something that is not my core business. I found a really good library, doing exactly what\'s need

Answer 1

Based on ΤΖΩΤΖΙΟΥ, Josh and Nosklo's answers i finally got it work using boost.python:

Python:

import thirdparty

def MyFunc(some_arg):
    result = thirdparty.go()
    return result

C++:

#include 
#include 
#include 

using namespace boost::python;

int main(int, char **) 
{
    Py_Initialize();

    try 
    {
        object module = import("__main__");
        object name_space = module.attr("__dict__");
        exec_file("MyModule.py", name_space, name_space);

        object MyFunc = name_space["MyFunc"];
        object result = MyFunc("some_args");

        // result is a dictionary
        std::string val = extract(result["val"]);
    } 
    catch (error_already_set) 
    {
        PyErr_Print();
    }

    Py_Finalize();
    return 0;
}

Some important points:

1. I changed 'exec' to 'exec_file' out of convenience, it also works with plain 'exec'.
2. The main reason it failed is that i did not pass a "local" name_sapce to 'exec' or 'exec_file' - this is now fixed by passing name_space twice.
3. If the python function returns unicode strings, they are not convertible to 'std::string', so i had to suffix all python strings with '.encode('ASCII', 'ignore')'.