Re: Class attributes

[Barry S. <ba...@ba...>]

On 21 Nov 2008, at 21:53, William Newbery wrote:

> I want add attributes to my c++ classes that can be used from  
> python. I know ive got to use the getattr method, however my  
> implementation crashes on the second access with an error about a  
> negative reference count.

     virtual Py::Object getattr(const char *name)
     {
         if(std::string("cls2")==name)return Py::asObject(cls2);
         else return getattr_methods(name);
     }


asObject takes ownership of cls2. And when the ref count drops to 0  
cls2 is deleted.
You then pass a pointer to a deleted object ot asObject as get a crash.

I suggest that you keep cls2 is a Py::Object so that you keep a ref  
count of 1 so long as Cls() exists.

I added std::cout to the c'tor and d'tor of your objects to prove this  
was the case.

Barry