Stefan Seefeld <stefan.seefeld@orthosoft.ca> writes:

hi there,

I'm compiling the following code with gcc 3.2:

#include <boost/python.hpp> namespace python = boost::python;

namespace {

class Bar {};

Bar *BarFactory() { static Bar bar; return &bar; }

}

BOOST_PYTHON_MODULE(Sandbox) { python::class_<Foo, boost::noncopyable> foo("Foo", python::no_init);

python::class_<Bar, boost::noncopyable> bar("Bar", python::no_init); bar.def("foo", &Bar::foo, python::return_internal_reference<>());

python::def("Bar", BarFactory, python::return_internal_reference<>()); //python::return_value_policy<python::manage_new_object>()); }

That compiles fine, but when I call the 'Bar' constructor from python, I get

...

...

...

from Sandbox import * bar = Bar() Traceback (most recent call last): File "<stdin>", line 1, in ? IndexError: tuple index out of range

What is going on here ?

return_internal_reference tries to bind the lifetime of the function's first argument to that of the result. Where's the first argument to Bar()?

What does the boost::python runtime do with the returned value that involves a tuple ?

Indexes into the argument tuple to do the lifetime binding.

When I replace the 'return_internal_reference<>' policy by 'return_value_policy<manage_new_object>' the function call returns successfully. But of course, that would crash at the end of the application...

See C:\boost\libs\python\doc\v2\reference_existing_object.html -- Dave Abrahams Boost Consulting www.boost-consulting.com