[fpc-devel] Proof of Concept ARC implementation

[Sven Barth]

Am 25.10.2014 03:17 schrieb "Hans-Peter Diettrich" <DrDiettrich1 at aol.com>:
>> - a class instance is destroyed once the reference count reaches zero
(and Free does not work for them)
>
>
> Shouldn't Free be usable as a finalizer, clearing all references to other
objects within this instance?

One could do that (for now I've chosen the simple way). One would however
need to check how this would be implemented best (e.g. it should be marked
somehow so that the destructor later on does not try to work with already
finalized fields; also all fields (Strings, arrays, interfaces, records,
etc.) should be finalized so that it is consistent). Also it needs to be
observed how other reference holders might react to that "zombie" instance.
A further problem might be legacy code which gets passed a reference
counted instance (on which ARCIncRef was called to keep it alive) and which
then calls Free. Might not be the intended result by neither code... This
might be the reason of Embarcadero to implement Free as a no-op and add a
new DisposeOf which does what you suggested.

Regards,
Sven
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