Re: Re: [boost] Shared_ptr "mini garbage collector"

From: Peter Dimov (pdimov_at_[hidden])
Date: 2003-01-07 12:09:16

From: "William E. Kempf" <wekempf_at_[hidden]>
> > From: "Peter Dimov" <pdimov_at_[hidden]>
> > From: "William E. Kempf" <wekempf_at_[hidden]>
> > > I think that extending it to free memory in cycles would be a great
idea.
> > Of course, this opens a large can of worms about how to handle
destruction
> > of objects which refer to each other...<
> >
> > One possible approach is to return a list of references to the
"offending"
> > shared_ptr instances to the user, who can then reset() them as
appropriate.
> > Actually it's not as simple as that since a reset() can invalidate some
of
> > the returned references; the shared_ptr instances would first need to be
> > copied to a temporary container, the originals reset(), and the
temporary
> > container destroyed, but the general idea is the same.
>
> This just pushes the issue off on the end user... who may not be any more
capable of dealing with the problem either.  If he can't do a lot of book
keeping to handle the circular problem, then pushing it off on him is not
much help.  And if he can do the book keeping, there's probably a solution
he can code into the destructors themselves.<

No, the user would not be expected to do any bookkeeping. He would only need
to call find_unreachable_objects() that would return a list of the
unreachable objects, and then, optionally, call break_cycles() with that
list as an argument. Or something like that. :-)