On 2009-04-18 22:25:32 +0200, Don <nos...@nospam.com> said:
Leandro Lucarella wrote:
Robert Jacques, el 18 de abril a las 11:56 me escribiste:
On Sat, 18 Apr 2009 11:24:14 -0400, Leandro Lucarella <llu...@gmail.com> wrote:
I've just found out[1] this[2]:
The garbage collector is not guaranteed to run the destructor for
all unreferenced objects.
Is there any reason why D can't guarantee that all finalizers will be
called, at least when the program ends?
when the main thread ends other threads might be running, and removing
memory they are using is not necessarily a good idea.
Exceptions might delay things indefinitely and allocate more memory.
Actually with tango you can tweak what will happen with
gc_getTermCleanupLevel (in gc.d), but I don't think that there is a
satisfying solution for everybody. I think that the default in tango is
quite reasonable (normal collect).
Well, a couple of quick tests show that under normal situations (i.e.
normal program termination and termination from an exception) the
finalizers do run (D2). However, if a finalizer throws an exception,
then the rest of the finalizers aren't called. Also, if you call
std.c.stdlib.exit, the finalizers won't run.
Well, I'm not talking about experimentation, I'm talking about source code
;)
The current GC implementation don't call finalizers for data that's still
reference when the program *ended* (this is allowed by the specs, so it's
fine, the question is why it's allowed by the specs).
I don't understand why D even has finalizers. Can they do anything useful?
Two things that I acn think of, there might be more:
- Release external resources. Well probably it is better not to rely on
them if the resource is finite (basically always), but it can be useful
at times
- weak refs
