Hi,

I found that answer for exceptions which can occur during the processing:

https://lists.boost.org/boost-users/2012/03/73904.php

Here is handled the case that exception is derived from std::exception. What happens if not? Can the parameter be changed to std::exception_ptr or just a template Parameter?

only std::exception are caught. Others just go through and interrupt the transition, which might leave the state machine in a dirty state, where an entry or exit action would not have been called. Cheers, Christophe