On Tuesday, 4 February 2014 at 20:16:20 UTC, Steven Schveighoffer
wrote:
On Tue, 04 Feb 2014 15:10:48 -0500, deadalnix
<deadal...@gmail.com> wrote:
On Tuesday, 4 February 2014 at 19:28:08 UTC, Steven
Schveighoffer wrote:
Where you have to be cognizant is avoiding cycles. Plain and
simple. And it's not that difficult. The compiler takes care
of the rest. It's somewhat magical I suppose :) Managing your
autorelease pools can make a difference, but is not
necessarily critical.
My experience is that, just like null reference, it is highly
dependent on the type of code you are facing.
Typically, you'll have trouble with complex graph of objects.
This is very true. I have only dealt with acyclic (except for
parent pointers) graphs or linked-lists.
For specialized cases, you will have to NULL out the pointers
to/from a node that has to be deleted (essentially a manual
delete).
But it works VERY well for linked-lists/queues. My app is I/O
intensive, so I have a lot of that.
-Steve
Yes.
Also, another issue comes up when you share data across threads.
Core can share a cache line in read mode, but can't in write
mode. That mean that updating the reference count will cause
contention on the cache line (core will have to fight for the
cache line ownership). That is why immutability + GC is so
efficient in a highly concurrent system, and ref counting would
ruin that.
