auto classes and finalizers

[Sean Kelly]

kris wrote:
> 
> Yes, it is. The "death tractors" (dtors in D) are notably less than 
> useful right now. Any dependencies are likely in an unknown state (as 
> you note), and then, dtors are not invoked when the program exits. From 
> what I recall, dtors are not even invoked when you "delete" an object? 
> It's actually quite hard to nail down when they /are/ invoked :)

I think dtors are called whenever an object is destroyed, be it via 
delete or by the GC.  And the GC should perform a complete clean-up on 
app termination.  I believe this is the current behavior in both Phobos 
and Ares (look at internal/gc/gc.d:gc_term() in Phobos and 
dmdrt/memory.d:gc_term() in Ares for the shutdown cleanup code).

> Given all that, the finalizer behaviour mentioned above sounds rather 
> like the current death-tractor behaviour?

It is exactly.  The dtor behavior has simply changed to be suitable for 
a more effective clean-up whenever the object is destroyed 
deterministically (ie. via delete or as an auto object).  I suppose an 
alternative would be to pass a state flag to the dtor to indicate the 
manner of disposal?  I really can't think of a means of implementing 
this that is as elegant as D deserves.


Sean