shared - i need it to be useful

[Nicholas Wilson]

On Tuesday, 16 October 2018 at 21:19:26 UTC, Steven Schveighoffer 
wrote:
> OK, so here is where I think I misunderstood your point. When 
> you said a lock-free queue would be unusable if it wasn't 
> shared, I thought you meant it would be unusable if we didn't 
> allow the implicit cast. But I realize now, you meant you 
> should be able to use a lock-free queue without it being 
> actually shared anywhere.
>
> What I say to this is that it doesn't need to be usable. I 
> don't care to use a lock-free queue in a thread-local capacity. 
> I'll just use a normal queue, which is easy to implement, and 
> doesn't have to worry about race conditions or using atomics. A 
> lock free queue is a special thing, very difficult to get 
> right, and only really necessary if you are going to share it. 
> And used for performance reasons!

I think this comes up where the queue was originally shared, you 
acquired a lock on the thing it is a member of, and you want to 
continue using it through your exclusive reference.