Python and shared_ptr

From: timfisken_at_[hidden]
Date: 2001-09-22 20:08:06

I've just started looking at boost::python, and I am having a litte 
difficulty with functions that take shared_ptr's as arguments. I'm 
not sure if this is due to me misunderstanding how boost::python is 
supposed to work, or a bug somewhere in my code, or g++ or something 
else entirely.

I created a class 'hello' based on the one in the getting_started2 
example, along with a free function 'invite' (again, as in the 
example). This worked fine. I then changed invite(const hello&) to 
invite(boost::shared_ptr<hello>). Now, when I try and call 'invite' 
from python, passing it a 'hello' instance created in python, I 
receive an error telling me that the extension class 'hello' does not 
wrap '<5hello>' (5hello, I discoverd, is what typeid(hello()).name() 
returns, for what that's worth).

I looked for references to any similar problems in the documentation 
and in the archive for this list, but I didn't see anything about 
this specific issue.

Have I misunderstood how boost::python interacts with smart pointers? 
invite(hello*) works the same as invite(hello&). Further, if I return 
a shared_ptr<hello> to python from a C++ function, this works just 
like a 'hello' instance in python, except that it _does_ work with 
shared_ptr version of 'invite'. This leads me to think that, from the 
python side, it is supposed to be transparent whether the C++ 
function takes a T&, a T* or a shared_ptr<T>. Is this not the case?

For what it's worth, I'm using boost 1.24.0, python 1.52 and g++ 
2.95.3; I don't know if one of these might be causing my 
difficulties, although I suspect the problem is of my own making.

Thanks,

-- 
Tim Fisken
223 King's College
07740 928082