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#Async... 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 When replying by private email, please remove the words spam and trap from the address shown in the header.