From: Tobias Peters <tpeters@...>
Date: 2004-10-26T07:54:06+09:00
Subject: Re: "add" function in swig and the ruby GC?

Richard P. Groenewegen wrote:
> Hi,
> 
> I'm trying to write an add-function in C++ with swig, but I think that
> ruby does not Garbage collect my objects.  Example:
> 
> class Thingy {
>     public:
>         Thingy() { }
>         ~Thingy() { cout << "Thingy is destructed."; }
> 
>         Thingy *add(const Thingy *other) const {
>             Thingy *result = new Thingy();
>             // ...
>             return result;
>         }
> }
> 
> Using GC.start I can check that ruby does not destruct Thingies made
> with "add".  So, what is the correct way to do this?  I could return a
> Thingy instead of a Thingy*, but is this the preferred(TM) way?

How could SWIG or Ruby possibly know that the pointer returned by your 
add method points to a newly created object on the heap. Swig does not 
interpret C++ Code, only types and signatures.

The solution to your problem is in the fine SWIG manual. Hint: %newobject

Tobias