[section boost/python/opaque_pointer_converter.hpp]

[section Introduction]

`opaque<>` registers itself as a converter from Python objects to pointers to undefined types and vice versa.

``

namespace boost { namespace python

{

template<class Pointee>

struct opaque

{

opaque();

};

}}

``

[endsect]

[section Class template `opaque` constructor]

``opaque();``

[variablelist

[[Effects][

* Registers the instance as a [link to_from_python_type_conversion.boost_python_lvalue_from_pytype_.class_template_lvalue_from_pytyp `lvalue_from_pytype`] converter from Python objects into opaque pointers.

The Python Objects created are named after the type pointed to by the opaque pointer being wrapped.

* Registers the instance as a [link to_from_python_type_conversion.boost_python_to_python_converter.class_template_to_python_convert `to_python_converter`] from opaque pointers to Python objects.

]]

]

[note If there is already an instance registered by another module, this instance doesn't try to register again in order to avoid warnings about multiple registrations.]

[endsect]

[section Macro `BOOST_PYTHON_OPAQUE_SPECIALIZED_TYPE_ID(Pointee)`]

This macro must be used to define specializations of the [link utility_and_infrastructure.boost_python_type_id_hpp.functions `type_id`] function which can't be instantiated for incomplete types.

[note The macro must be invoked in every translation unit which uses the opaque converter.]

[endsect]

[endsect]