A bug in my code

[Sergey Gromov]

Jarrett Billingsley <jarrett.billingsley at gmail.com> wrote:
> On Sun, Sep 7, 2008 at 12:59 PM, bearophile <bearophileHUGS at lycos.com> wrote:
> > Uhm... I don't understand fully: do you mean roots don't become deleted
> > when they have nothing that points to them?
> > The docs say:
> > "Roots are references to memory allocated by the collector that are
> > maintained in memory outside the collector pool."
> 
> I think what you should be using instead is addRange.  addRoot more or
> less tells the GC "never collect memory referenced by this pointer",
> but it doesn't actually scan the memory _pointed to_ by the roots for
> pointers.

This just cannot be.  A root is a place where a tree of live memory 
objects is grafted.  That's why it is called a "root".  A memory block 
pointed to by a root is kept alive and, obviously, scanned for pointers 
to other memory blocks if it hasPointers().

There's a problem with addRoot() that, if the memory block is re-
allocated, the old root stops serving its purpose.  In that case you 
need to remove an old root and add the new one, pointing into the re-
allocated block.