Hi Norbert,

I couldn't have said it any better. For me, this also was interesting, because I first thought: "Heck, how would I make anything atomic anyways?".
And that question still stands: is there a way to make something atomic that includes message sends? I guess #critical is not the solution, is it?

Joachim

Am 14.11.13 11:12, schrieb Norbert Hartl:

Am 14.11.2013 um 10:25 schrieb Marcus Denker <marcus.denker@inria.fr>:

On 14 Nov 2013, at 10:15, Stephan Eggermont <stephan@stack.nl> wrote:

Reading this code, made me wonder what operations are actually atomic.
Anyone having a good explanation?

Stephan

AtomicQueueItem>makeCircular
� � � � "Make a receiver circular, i.e. point to itself,
� � � � answer the old value of next variable.
� � � � Note, this operation should be atomic"
� � � �
� � � � | temp |

� � � � " atomic swap here"
� � � � temp := next.
� � � � next := self.

� � � � ^ temp

-> no message send
-> no back jump bytecode

therefore it can not be interrupted and process switches can not happen between the statements.

Thanks, I learn something new every day. I�ve never thought about the condition when a process switch can happen. Can you say in short when a switch of processes is checked? Because I think I won�t finding it in a reasonable time looking myself.

Norbert

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