draft proposal for ref counting in D

[Sönke Ludwig]

Am 13.10.2013 17:15, schrieb Sean Kelly:
> On Sunday, 13 October 2013 at 07:03:39 UTC, Rainer Schuetze wrote:
>>
>> According to the "Handbook of Garbage Collection" by Richard Jones
>> eager lock-free reference counting can only be done with a cas2
>> operation modifying two seperate locations atomically (algorithm 18.2
>> "Eager reference counting with CompareAndSwap is broken"). This might
>> be the quoted paper:
>> http://scholr.ly/paper/2199608/lock-free-reference-counting
>>
>> Unfortunately the CAS2 operation does not exist in most processors.
>
> I suppose it's worth noting that Boost (and now standard C++) has a
> shared_ptr that works across threads and the implementation I've seen
> doesn't use a mutex.  In fact, I think the Boost one doesn't even use
> CAS on x86, though it's been quite a few years so my memory could be
> wrong on that last detail.

I didn't read the paper, but I'd suspect that the paper refers to the 
case where both, the reference count _and_ the reference is thread-safe, 
since the boost/c++ shared_ptr only has a thread-safe reference count 
after all.