Dear Mr. Andreas Huber, Are completion transitions and events supported by the Statechart Boost library? If so, how do you recommend they should be implemented in code. I have not found examples of statemachines containing transitions *without* explicit triggers in your library's doc page (http://www.boost.org/libs/statechart/doc/index.html). Thank you, Francisco Santos PS: I have included the definition of a completion transition and completion event for reference: A completion transition is a transition without an explicit trigger, although it may have a guard defined. When all transition and entry actions and activities in the currently active state are completed, a completion event instance is generated. This event is the implicit trigger for a completion transition. The completion event is dispatched before any other queued events and has no associated parameters. For instance, a completion transition emanating from a concurrent composite state will be taken automatically as soon as all the concurrent regions have reached their final state. If multiple completion transitions are defined for a state, then they should have mutually exclusive guard conditions. [1] "Completion transitions and completion events", p. 144, Unified Modeling Language Specification, v1.4.2, 2004