#include <boost/mpl/list.hpp>

#include <boost/statechart/simple_state.hpp>

#include <boost/statechart/state_machine.hpp>

#include <boost/statechart/event.hpp>

#include <boost/statechart/transition.hpp>

#include <boost/statechart/custom_reaction.hpp>

namespace sc = boost::statechart;

struct Event1 : sc::event<Event1> {};

struct Event11 : sc::event<Event11> {};

struct Meta;

struct Machine : sc::state_machine<Machine, Meta> {};

struct Meta2 : sc::simple_state<Meta2, Machine> {

  Meta2() { std::cout << "Meta2\n"; }

};

struct Inner1;

struct Inner2;

struct Meta : sc::simple_state<Meta, Machine, boost::mpl::list<Inner1, Inner2>> {

  Meta() { std::cout << "Meta\n"; }

  typedef sc::transition<Event1, Meta2> reactions;

};

struct Inner11 : sc::simple_state<Inner11, Meta::orthogonal<0>> {

  Inner11() { std::cout << "Inner11\n"; }

  typedef sc::custom_reaction<Event1> reactions;

  sc::result react(const Event1& ev) {

    std::cout << "Inner1 reaction\n";

    return forward_event();

  }

};

struct Inner1 : sc::simple_state<Inner1, Meta::orthogonal<0>> {

  Inner1() { std::cout << "Inner1\n"; }

  typedef sc::transition<Event11, Inner11> reactions;

};

struct Inner2 : sc::simple_state<Inner2, Meta::orthogonal<1>> {

  Inner2() { std::cout << "Inner2\n"; }

};

int main() {

  Machine m;

  m.initiate();

  m.process_event(Event11());

  m.process_event(Event1());

 

  return 0;

}

////////////////////

That gives me output:

Meta                                                                                                                                                                                           Meta2