[cpp-threads] New strawman proposal

[Doug Lea]

Boehm, Hans wrote:

> 
>>2. Leaving the semantics of anything with cycles undefined 
>>might be the best we can do, but means that many programs 
>>will unknowingly be ill-formed. I suppose it is possible to 
>>create tools that can detect and inform programmers about 
>>such constructions.
> 
> Do you have an example in mind here?
> 
> Actually, my intent was that a cycle generally reflects
> an infeasible synchronizes-with relation.  I think we're not
> outlawing
> 
> Initially x = y = 0, x and y are unordered synchronization
> variables:
> 
> Thread 1			Thread 2
> x = y				y = x
> 
> Outcome: x = y = 42
> 

What if the reads here are atomic.readAcquire
and writes were atomic.storeRelease (or whatever
we decide to call these)?



> I'd like to see a prototype of at least the interface.
> (If we had a candidate interface, I'd be interested in trying
> to implement it in terms of atomic_ops, updating that
> if necessary.  That should give us a semi-portable
> prototype.)

I posted a couple of starts on this that got shot down;
I believe Peter Dimov is the last person to volunteer
to give it a shot?

-Doug