auto classes and finalizers

[Georg Wrede]

kris wrote:
> Sean Kelly wrote:
>> kris wrote:
>>> Jarrett Billingsley wrote:
>>>>
>>>> Hmm.  'auto' works well and good for classes whose references are 
>>>> local variables, but .. what about objects whose lifetimes aren't 
>>>> determined by the return of a function?
>>>>
>>>> I.e. the Node class is used only in LinkedList.  When a LinkedList 
>>>> is killed, all its Nodes must die as well.  Since the Node 
>>>> references are kept in the LinkedList and not as local variables, 
>>>> there's no way to specify 'auto' for them.
>>>
>>> Heck, the LinkedList dtor /cannot/ rely on the nodes being valid if 
>>> they are also managed by the GC :)
>>>
>>> So, as I understand it, one cannot legitimately execute that example.
>>
>> ...unless the LinkedList has a deterministic lifetime :-)
> 
> <g> Touché !

Hey, hey, hey...

If anybody deletes stuff from a linked list, isn't it their 
responsibility to fix the pointers of the previous and/or the next item, 
to "bypass" that item??????

The mere fact that no "outside" references exist to a particular item in 
a linked list does _not_ make this item eligible for GC.

Not in the current implementation, and I dare say, in no future 
implementation ever.

In other words, it is _guaranteed_ that _all_ items in a linked list are 
valid.

This could be called a "linked-list-invariant". :-)