Question

I was wondering if any one here might be able to help me out with the following problem I’m having.

I seem unable to create a boost::python::object from a c++ class I’ve bound to python that is noncopyable. Here is a simplified example..

#include <boost/python.hpp>

class A
{
public:
    static A*
    create() {return new A;}

protected:
    A(){}
};

void
doSomething(const A& a)
{
    boost::python::object obj(a);
}

BOOST_PYTHON_MODULE(test)
{
    boost::python::class_<A, boost::noncopyable>("A", boost::python::no_init)
    .def("__init__", boost::python::make_constructor(&A::create));

    boost::python::def("doSomething", &doSomething);
}

Then at runtime in python

import test
a = test.A()
test.doSomething(a)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: No to_python (by-value) converter found for C++ type: A

I realise that the boost::noncopyable parameter prevents a to_python converter for A being registered. Does anyone know how I might be able to create a boost::python::object from an A instance ?

thanks in advance!

Answer 1

Use this

boost::python::object obj(**boost::cref(a)**);