Boost.Python from Python to FILE* wrapper

file_wrapper.cpp

#include <boost/python.hpp>
#include <iostream>

namespace {
  void *convert_to_FILEptr(PyObject* obj) {
    return PyFile_Check(obj) ? PyFile_AsFile(obj) : 0;
  }
}

void test_argument(FILE* f) {
  fprintf(f, "Written from C++\n");
}

void test_extract(boost::python::object obj) {
  PyObject_Print(obj.ptr(), stdout, 0);
  boost::python::extract<FILE*> get_file(obj);
  if (get_file.check())
    std::cout << " can be converted to FILE*" << std::endl;
  else
    std::cout << " is not a FILE*" << std::endl;
}

BOOST_PYTHON_MODULE(file_wrapper) {
  boost::python::converter::registry::insert
    (convert_to_FILEptr,
     boost::python::type_id<FILE>(),
     &boost::python::converter::wrap_pytype<&PyFile_Type>::get_pytype);

  boost::python::def("test_argument", &test_argument);
  boost::python::def("test_extract", &test_extract);
}

file_wrapper_test.py

import file_wrapper

with open('test.txt', 'rw') as f:
    # Use the Boost.Python argument to FILE* converter.
    file_wrapper.test_argument(f)

    # Read the results.
    f.seek(0)
    print f.readline()

    # Test using extract<FILE*>
    file_wrapper.test_extract(None)
    file_wrapper.test_extract(f)
    file_wrapper.test_extract(45)