[C++-sig] return boost::shared_ptr<some internal>

[Alex Leach]

On Fri, 14 Jun 2013 12:57:48 +0100, Neal Becker <ndbecker2 at gmail.com>  
wrote:

> I have a class that has a member
>
> something like this:
>
> class A {
>   boost::shared_ptr<B> b;
>
> };
>
> boost::shared_ptr<B> get_b (A const& ...) {
>   return A.b;
> }
>
> where class B is already exposed to python in a different module.


I think this depends on (at least) a few things:-

   1. libboost_python shouldn't be linked statically into each extension.  
If it is, then the to_python converter registry will be duplicated in each  
extension, so one extension module wouldn't be able to locate to python  
converters (e.g. class_'s) registered in other extensions.

   2. Class B will need to be exposed with a shared_ptr as its instance  
holder / object manager(?).. e.g.

class_<B, shared_ptr<B> >
    ...

   3. Like you've said, you'll also need to import B into Python, but as  
there's no inheritance involved between A and B (no 'bases<>' declared), I  
don't think the import order is completely relevant here, so long as both  
modules have inserted their to_python converters into a single registry.

HTH,
Alex