On 10/16/18 6:24 PM, Nicholas Wilson wrote:
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.
Isn't that a locking queue? I thought we were talking lock-free?
-Steve
