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From: Kim Chang Han (chkim_at_[hidden])
Date: 2003-02-26 21:55:50

Here is my simple test code modified from embedding.cpp test code(by Dirk Gerrits).

I successfully compiled, but my excutable raise heap error assertion when the time freeing the string result of the function py.hello().

Can I prevent this error?

My sampel code and result is below.

// main.cpp

// Copyright David Abrahams 2002. Permission to copy, use,
// modify, sell and distribute this software is granted provided this
// copyright notice appears in all copies. This software is provided
// "as is" without express or implied warranty, and with no claim as
// to its suitability for any purpose.

// embedded_hello -- A simple Boost.Python embedding example -- by
// Dirk Gerrits

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

namespace python = boost::python;

// An abstract base class
class Base //: public boost::noncopyable
    virtual ~Base() {};

    virtual std::string hello() { return "base"; }

// C++ derived class
class CppDerived : public Base
    virtual ~CppDerived() {}
    std::string hello()
        return "Hello from C++!";

// Familiar Boost.Python wrapper class for Base
class BaseWrap : public Base
    BaseWrap(PyObject* self_)
        : self(self_) {}

    std::string hello() { return python::call_method<std::string>(self, "hello"); }

    PyObject* self;

// Pack the Base class wrapper into a module
    python::class_<Base, BaseWrap, boost::noncopyable>("Base")


void test()
//- INITIALIZATION -----------------------------------------------------------//
        PyObject * mod;

    // Register the module with the interpreter
    if (PyImport_AppendInittab("embedded_hello", initembedded_hello) == -1)
        throw std::runtime_error("Failed to add embedded_hello to the interpreter's "
                                 "builtin modules");

    // Initialize the interpreter

    mod = PyImport_ImportModule("Phello");

    // Retrieve the main modules namespace
        python::handle<> mod_namespace(

    // Extract the raw Python object representing the just defined derived class
    python::handle<> class_ptr(
        PyRun_String("PythonDerived\n", Py_eval_input,
                     mod_namespace.get(), mod_namespace.get()) );

    // Wrap the raw Python object in a Boost.Python object
    python::object PythonDerived(class_ptr);

//- MAIN PROGRAM -------------------------------------------------------------//

    // Creating and using instances of the C++ class is as easy as always.
    CppDerived cpp;
    std::cout << cpp.hello() << std::endl;

    // But now creating and using instances of the Python class is almost
    // as easy!
    python::object py_base = PythonDerived();
    Base& py = python::extract<Base&>(py_base)();
    std::cout << py.hello() << std::endl; //<<=== ERROR From here when freeing py.hello() result string


int main()
    if (python::handle_exception(test))
        if (PyErr_Occurred())
        return 1;
    return 0;

from embedded_hello import *

class PythonDerived(Base):
        def hello(self):
                return 'Hello from Python!'

PObj = PythonDerived()
print PObj.hello()

// Result

Hello from Python!
Hello from C++!
Hello from Python!
// and error!

Debug Assertion Failed!

Program : C:\\xxxxx
File: dbgheap.c
Line : 1044

Expression: _CrtlsValidHeapPointer(pUserData)


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