Subject: Re: [Boost-users] [Statechart] Question regarding state_machine eventhandling
From: Andreas Huber (ahd6974-spamboostorgtrap_at_[hidden])
Date: 2010-02-26 12:32:04
> That's good to know - I did not realize that. From the tutorial and the
> reference I had the impression that a separate thread would be needed for
> every
> other state machine, and I also wanted to go the easy way first ;-)
> I'll give it a try; according to the reference all functionality I need
> seem to
> be available.
Ok, let me know if you have any trouble. Async machines differ quite a bit
from sync ones.
>> state_machine<>::post_event() is not intended to be called from code
>> "outside" of the machine, but only transition actions, which is why
>> post_event is documented as being protected. Unfortunately, it is public
>> in
>> the code because it has to be called from other class templates and
>> template
>> friend support was very spotty at the time this was implemented. Anyway,
>> I
>> certainly could have done more to prevent calls from outside (e.g. with
>> an
>> assert and/or better documentation). May I ask you to enter a ticket for
>> this?
> Sure, the ticket is opened.
Thanks.
> Regarding my other questions about the synchroneous state machine: is it
> really
> intended that a new event is processed before other events already queued?
> Of
> course this might be related to the post_event() issue above - if events
> cannot
> be queued up from outside without being processed immediately, the queue
> cannot
> contain any pending events. Right?
Correct, if post_event is only ever called from transition actions then the
posted events are processed as the last step of process_event, so there
cannot be any event ordering issues.
Regards,
Andreas