Re: [Boost-users] [statechart] Question about do activities

Subject: Re: [Boost-users] [statechart] Question about do activities
From: Bill Clark (bill_at_[hidden])
Date: 2009-04-22 12:01:42

Hi Andreas,

Ok, I was thinking that you were equating cancellation with interruption. My
reference to a stop() function was meant as a placeholder for any kind of
function (other than cancellation or interruption) that tells an active
object to quit processing and clean up after itself. A function like that is
needed if cancellation/interruption aren't available.

So, would the following statements be true?

- boost::statechart imposes no requirements on do-activity threads, other
than that they stop when instructed to (by whatever means) and that they
clean up after themselves.
- Any timing requirements on how quickly the thread actually exits are
determined by the design of the application; boost::statechart itself
imposes no such requirements.

Bill

On Wed, Apr 22, 2009 at 2:11 AM, Andreas Huber <
ahd6974-spamboostorgtrap_at_[hidden]> wrote:

> Hi Bill
>
>  I see that I'm way behind the times on boost::thread - I hadn't realized
>> that cancellation had been added to it.
>>
>
> Interruption has been added to it, which is not what I had in mind with
> cancellation. The former only allows to "stop" a thread at predefined points
> (usually when the thread is waiting on a lock or a condition variable, etc.
> The latter allows to "stop" a thread anywhere (even when it is executing a
> while (true) {} loop).
>
> In order to be useful for the general case, both actions must lead to an
> exception being thrown in the target thread. An exception is required so
> that acquired resources can be cleaned up correctly, which is why I put the
> word stop in quotes above. The thread isn't really stopped immediately, it's
> just instructed to start cleaning up as soon as possible.
>
>  So, I'll rephrase the question - from the point of view of
>> boost::statechart, is there a reason to prefer cancellation over some
>> other
>> means of stopping a thread, like calling a stop() function and then
>> join()?
>>
>
> Boost.Thread doesn't offer stop(). Which threading API do you have in mind?
>
> Regards,
>
> --
> Andreas Huber
>
> When replying by private email, please remove the words spam and trap
> from the address shown in the header.
>
> _______________________________________________
> Boost-users mailing list
> Boost-users_at_[hidden]
> http://lists.boost.org/mailman/listinfo.cgi/boost-users
>