[C++-sig] Constructors in callback classes.

[Brett Calcott]

>
> Good point. I need to add a note in
>   http://www.boost.org/libs/python/doc/v2/class.html#HeldType
> and Joel should add something in
>
http://www.boost.org/libs/python/doc/tutorial/doc/class_virtual_functions.ht
ml
>
> Thanks for pointing it out.

In the same area, the class_ definition is like this (4 args):

template <class T
          , class Bases = bases<>
            , class HeldType = T
            , class NonCopyable = unspecified
           >
  class class_ : ....

But the docs and examples of wrapping do this (Only 3 args):

class_<Base, BaseWrap, boost::noncopyable>("Base", no_init)

This is confusing.

I had a look at the header and see you do something I don't (yet) understand
to make this happen. Very cool.

Cheers,
Brett