Something needs to happen with shared, and soon.

[David Nadlinger]

On Thursday, 15 November 2012 at 23:22:32 UTC, Sean Kelly wrote:
> On Nov 15, 2012, at 3:05 PM, David Nadlinger 
> <see at klickverbot.at> wrote:
>> Well, to be picky, that depends on what kind of memory 
>> operation you mean – moving non-volatile loads/stores across 
>> volatile ones is typically considered acceptable.
>
> Usually not, really.  Like if you implement a mutex, you don't 
> want non-volatile operations to be hoisted above the mutex 
> acquire or sunk below the mutex release.  However, it's safe to 
> move additional operations into the block where the mutex is 
> held.

Oh well, I was just being stupid when typing up my response: What 
I meant to say is that you _can_ reorder a set of memory 
operations involving atomic/volatile ones unless you violate the 
guarantees of the chosen memory order option.

So, for Andrei's statement to be true, shared needs to be defined 
as making all memory operations sequentially consistent. Walter 
doesn't seem to think this is the way to go, at least if that is 
what he is referring to as »memory barriers«.

David