Re: [boost] [interprocess] Atomic read and write.

From: Markus Schöpflin (markus.schoepflin_at_[hidden])
Date: 2007-10-10 12:19:22

Ion Gaztañaga schrieb:

> Markus Schöpflin escribió:
>> Hello,
>>
>> this may be a silly question, but I have been wondering what the atomic 
>> read and write primitives are actually supposed to do?
>>
>> I mean, from the readers or writers POV a read or write is always atomic, 
>> isn't it? Am I missing something very obvious here?
> 
> In some architectures, a 32 read might not be atomic (even if the read 
> is aligned). I think that Intel system is always atomic. They are there 
> for completeness, to support systems where read or write might not be 
> atomic.

Sorry for being dense, but what exactly do you mean when you say a read 
might not be atomic? Are you thinking of memory barriers here? Or is it 
something else? Is there somewhere a definition of what atomic exactly 
means here?

I'm asking because I'm currently evaluating how much of work it would be 
to make interprocess work on Tru64.

Markus