Dare I ... another volatile discussion ?

[Jens Bauer via Digitalmars-d]

On Thursday, 7 May 2015 at 21:42:08 UTC, Iain Buclaw wrote:
> On 7 May 2015 at 23:39, Iain Buclaw <ibuclaw at gdcproject.org> 
> wrote:
>> When used properly though, it's properties make it a prime 
>> candidate
>> for the foundation of libraries/programs that centre around 
>> the use of
>> atomics.  However, shared is not to be confused with a 
>> thread-safe
>> atomic type.  Thread-safety is left to the end-user on such 
>> matters of
>> access.
>>
>
> That last sentence should also include a mention of memory 
> ordering
> too being left to the end-user.

Thank you for explaining this; it does make sense. :)

-So 'shared' is not to be confused with 'atomic'; its behaviour 
seems closer to C's "extern", do I understand this correctly ?

One of the reasons I asked the question, is because no doubt D 
will need to write to hardware on any kind of platform, and I'd 
like it to be the same on both microcontrollers and a Personal 
Computer (not limited to a specific kind of processor).

Another thing, slightly related, is 'atomic'. C's implementation 
allows you to have a function, which reads/modifies/writes a 
value atomically. This is all implemented 'outside' the C 
language.
Would it make sense to mark a variable 'atomic', or would it be 
rather crazy, because if it's extern(C) anyway, C wouldn't access 
it atomically ?