Re: Best Ref-counting algorithms?

Christoffer LernC6 wrote:
>> But what language are you planning use for the implementation? If you
>> choose C++, then it is hard to find the root set. Suppose you create
>> object for use in your language; then global objects and those in th
>> stack should be registered somehow for the tracing, but those on the
>> heap should not, as the are live when they can be traced from the other.
>
> I was thinking of using C for implementation, but does that matter? As
> long as I implement the language in a non GC:ed language I will have
> to take care of writing the GC myself (or for C, use the Bohm
> conservative GC).


If you want to make a tracing GC in C++, then you will have to keep
track of where elements are located by hand.


For example, if you have class Object which keep track of a polymorphic
pointer, and a
      class S {
          Object x, y;
          ...
      };


Then in
      T f(...) {
          Object w = new S(...);
          ...
      }
the w belongs to the root set, as it is allocation on the function
stack, whereas the S::x, S::y are on the heap, as they are allocated via
the "new S".


So at least for dynamic languages, this is problem.


      Hans

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