Re: [boost] New New Callbacks Uploaded

From: Michael D. Crawford (crawford_at_[hidden])
Date: 2000-11-24 04:05:50

> And
> then there's multithreading.

I know it take extra effort, but you can do reference counting with 
multithreading.  The ZRef reference counted smart pointer in ZooLib handles 
multithreading correctly.

You could probably lift out ZRef and ZAtomic from ZooLib and use them on 
their own for multithreaded reference counting without using the rest of 
ZooLib.  http://zoolib.sourceforge.net

It does this by using atomic addition and subtraction on the reference 
counts when it's getting operated on.  So if you have two threads 
incrementing and decrementing the reference count it does the right thing.

It wasn't easy for Andy Green to get it right, considering also the cross-
platform issues (and we found a small  compiler bug when doing the atomic 
operations) but it does seem to work correctly.

Regards,

Mike Crawford