[C++-sig] "extension class wrapper for base class has not been created yet" error message on Linux for a project that works fine on Windows

[Andras Pap]

I am creating a base class "Base::Foo" in Foo.dll(so) and expose it in 
the FooWrapper.pyd(so) module. Class "Derived::Bar" derives from 
Base::Foo and is in the Bar.dll(so) and exposed in the 
BarWrapper.pyd(so) module.

On Windows the following works fine:
Python 2.4.2 (#67, Sep 28 2005, 12:41:11) [MSC v.1310 32 bit (Intel)] on 
win32
Type "help", "copyright", "credits" or "license" for more information.
 >>> import FooWrapper
 >>> import BarWrapper
 >>> foo = FooWrapper.Foo()
 >>> bar = BarWrapper.Bar()
 >>> foo.sayHello()
Hi I am Foo!
 >>> bar.sayHello()
Hi I am Bar!
 >>>

On Linux I get the:
RuntimeError: extension class wrapper for base class Base::Foo has not 
been created yet error:
Python 2.4.2 (#1, Jul  2 2008, 10:27:50)
[GCC 3.2.3 20030502 (Red Hat Linux 3.2.3-59)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> import FooWrapper
 >>> import BarWrapper
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
RuntimeError: extension class wrapper for base class Base::Foo has not 
been created yet
 >>>

Instantiating "foo" before trying to import BarWrapper does not help:
Python 2.4.2 (#1, Jul  2 2008, 10:27:50)
[GCC 3.2.3 20030502 (Red Hat Linux 3.2.3-59)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> import FooWrapper
 >>> foo = FooWrapper.Foo()
 >>> foo.sayHello()
Hi I am Foo!
 >>> import BarWrapper
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
RuntimeError: extension class wrapper for base class Base::Foo has not 
been created yet
 >>>

I am hoping that I am missing a simple step, can anyone help what it may be?


Here are: Foo.cpp/h, FooWrapper.cpp Bar.cpp/h and BarWrapper.cpp:
foo.h:
#ifndef BASE_FOO_H
#define BASE_FOO_H

namespace Base
{

  class TEST_BASE Foo
  {

  public:
    /// ctor
    Foo();

    /// dtor
    virtual ~Foo();

    virtual void sayHello();
  };

} // namespace Base

#endif //BASE_FOO_H

foo.cpp:
#include <iostream>
#include "Foo.h"

using namespace Base;

Foo::Foo()
{
};

Foo::~Foo()
{
};

void Foo::sayHello()
{
  std::cout << "Hi I am Foo!" << std:: endl;
}

FooWrapper.h:
#include <vector>
#include <string>

#include <boost/python/class.hpp>
#include <boost/python/module.hpp>

#include <Foo.h>

BOOST_PYTHON_MODULE(FooWrapper)
{
  using namespace std;
  using namespace boost::python;
  using namespace Base;

  // Python wrapper for MaterialDocument
  class_<Foo>("Foo")
    .def("sayHello", &Foo::sayHello)
    ;
}

Bar.h:
#ifndef DERIVED_BAR_H
#define DERIVED_BAR_H

#include "Foo.h"

namespace Derived
{

  class TEST_DERIVED Bar : public Base::Foo
  {

  public:
    /// ctor
    Bar();

    /// dtor
    virtual ~Bar();

    virtual void sayHello();
  };

} // namespace Derived

#endif //DERIVED_BAR_H

Bar.cpp
#include <iostream>
#include "Bar.h"

using namespace Derived;

Bar::Bar() : Base::Foo()
{
};

Bar::~Bar()
{
};

void Bar::sayHello()
{
  std::cout << "Hi I am Bar!" << std:: endl;
}

BarWrapper.cpp
#include <vector>
#include <string>

#include <boost/python/class.hpp>
#include <boost/python/module.hpp>

#include <iostream>
#include <string>

#include <Bar.h>

BOOST_PYTHON_MODULE(BarWrapper)
{
  using namespace std;
  using namespace boost::python;
  using namespace Derived;

  // Python wrapper for MaterialDocument
  class_<Bar, bases<Base::Foo> >("Bar")
    .def("sayHello", &Bar::sayHello)
    ;
}




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Andras Pap               Ph:(617)497-6880x233
Coventor, Inc.           Fax: (617)497-6882
apap at coventor.com        Cell: (617)512-5768
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