Re: [Boost-users] Statechart problem

Subject: Re: [Boost-users] Statechart problem
From: Andreas Huber (ahd6974-spamboostorgtrap_at_[hidden])
Date: 2009-03-25 12:34:01

> I guessed that was the problem indeed I followed the event go pushed into
> the event queue but it miraculously disappears somewhere very strange.

It doesn't disappear. It's simply held in the internal queue until you call 
process_event() the next time. However, as I said before it's not a good 
idea to use post_event this way.

> If I would make an event which encapsulates the message I would still
> need to send it from another thread and then I could only use the
> statemachine.process_event( EvEvent() ) mechanism. I tried that and the
> behavior was not exactly what I needed. The calling function would not
> leave the process_event method and hold op the system.

state_machine is not thread-safe and, more importantly, not reentrant, as 
documented here:

http://www.boost.org/doc/libs/1_38_0/libs/statechart/doc/tutorial.html#AsynchronousStateMachines

So both of the approaches you tried are dangerous, to say the least.

> Maybe I should start thinking about rewriting the code to use the
> asynchronous_state_machine.

Yes, that sounds like a good idea. The usage of asynchronous_state_machine 
is very different from the one of state_machine, so don't hesitate to post 
here if you run into any problems.

HTH,

-- 
Andreas Huber
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