Re: Aliasing and Garbage Collection

[M_Boosten <mboosten@xxxxxxxxxxxxxxxxxxx>]

> > Some more remarks on the performance overhead of Garbage Collection:
> > The overhead of Garbage Collection can be O(#pointercopies).
> > Use the following scheme:
> >   - when allocating a memory fragment, register the object is shared
> >     once "shareCount = 1"
> >   - when copying a pointer, register the object is shared once more
> >     "shareCount++"
> >   - register the release of a pointer.
> >     void free { sharedCount--; if (sharedCount==0) { call private free } }
> 
> Reference counting is subject to memory leaks when cycles exist. Object A
> contains a ptr to B, B contains a ptr to A, but both are unreachable from
> the program. They are not reclaimed as both have a sharedCount of 1.
> 
> Algorithms which do not suffer from this problem are (I believe)
> considerably more expensive.

You are right: in case of bad OO designs, it does not work.
Normally (using standard design practices), I would not expect
these situations not to occur.

I think one always has some graph-like structure in mind for
"ownership".  This is what you suggest as well...?

Cheers,
	Marcel