Using Boost Python & std::shared_ptr

Question

I\'m trying to get Boost Python to play nicely with std::shared_ptr. Currently, I\'m receiving this error:

Traceback (most recent call last):
  File \"test.py\",         


        

Answer 1

Unless I've misunderstood, I think this solves your problem:

boost::python::register_ptr_to_python<std::shared_ptr<Anchor>>();

http://www.boost.org/doc/libs/1_57_0/libs/python/doc/v2/register_ptr_to_python.html

Answer 2

Looks like boost::python doesn't support C++ 11 std::shared_ptr.

If you have a look to file boost/python/converter/shared_ptr_to_python.hpp you'll find implementation of template function shared_ptr_to_python(shared_ptr<T> const& x) for boost::shared_ptr (it explain why the code works fine for boost::shared_ptr).

I think you have several options:

• use boost::shared_ptr (which you trying to avoid)
• write your implementation of shared_ptr_to_python for std::shared_ptr (IMHO the best option)
• send request to boost::python developers to support std::shared_ptr

Answer 3

There's a bug report for this: https://svn.boost.org/trac/boost/ticket/6545

Looks like someone is working on it.

Answer 4

A snippet from http://boost.2283326.n4.nabble.com/No-automatic-upcasting-with-std-shared-ptr-in-function-calls-td4573165.html:

/* make boost::python understand std::shared_ptr */
namespace boost {
       template<typename T>
       T *get_pointer(std::shared_ptr<T> p)
       {
               return p.get();
       }
}

Worked for me. You would define your classes like:

class_<foo, std::shared_ptr<foo>>("Foo", ...);

With this, other methods returning std::shared_ptr<foo> will Just Work.

Some magic may be required for virtual functions/polymorphism, that should be covered in the thread I linked to.