[C++-sig] Efficient string passing

[Mohan Ganesalingam]

Dear all,

I recently sent an e-mail which (I think) didn't reach the list, about 
trying to return large strings from C++ into Python without copying them. 
By looking at the C/Python API I've subsequently figured out roughly how to 
do this... something like

Class World
{
	object return_object()
	{
		PyObject *result = PyString_FromStringAndSize(0, 7);
		// initialise the underlying string using PyString_AsString 
		handle<> h(result);
		return object();
	}

...

		
main_namespace["World"] = class_<World>("World")
.def("return_object", &World::return_object);
									
Unfortunately this doesn't work; when I call w.return_object(), I get back 
None. Returning a raw PyObject * instead of a boost::python::object works, 
but I can't tell if that involves a copy... and using 
return_value_policy<manage_new_object>() with a PyObject * return crashes.

Any advice here would be very much appreciated!

Thank you and best wishes,
Mohan