Christopher Wright wrote:
grauzone wrote:
Jarrett Billingsley wrote:
On Sun, Mar 29, 2009 at 4:42 PM, Leandro Lucarella <llu...@gmail.com>
wrote:
This was discussed several times in the past. For example:
http://www.digitalmars.com/d/archives/digitalmars/D/learn/weak_references_13301.html
http://www.digitalmars.com/d/archives/digitalmars/D/learn/Soft_weak_references_8264.html
http://www.digitalmars.com/d/archives/digitalmars/D/announce/ANN_WeakObjectReference_-_class_to_hold_weak_references_9103.html
etc.
I hope it helps.
The one provided by Bill:
http://www.dsource.org/projects/scrapple/browser/trunk/weakref
seems to work fine, and has the advantage of working in both Phobos
and Tango.
First, I doubt this actually works. The WeakRef stores the pointer as
size_t, but the GC is conservative and will still recognize the size_t
as a pointer. The unittest in the existing code only works, because he
uses an explicit delete on the referenced object.
If the WeakRef is on the stack, this is true.
If the WeakRef is part of an aggregate type that contains pointers, this
is true.
If WeakRef is a class, this is also true. Because all objects contain a
hidden monitor pointer, and the monitor is subject to garbage collection
AFAIK.
Otherwise, the GC will see that the relevant block is marked as having
no pointers.
True -- weakref is a difficult thing to make thread-safe.
It seems there's still work to do, and a thread-safe WeakRef can't be
created with the current interfaces. Is this true?
I'm thinking rt_attachDisposeEvent() should take a *pointer* to the
reference instead of the reference itself (effectively a double
pointer), and clear this pointer during garbage collection, when all
threads are still globally locked.
