Hello, In my application I use a few async state-machines with lots of events. I'd like to trace some events construction/destruction balance, so I define them as follows: volatile long eventCount; template<class MostDerived> struct EvBase : sc::event<MostDerived> { EvBase() { long c = InterlockedIncrement(&eventCount); somelog << c << std::endl; } ~EvBase() { long c = InterlockedDecrement(&eventCount); somelog << c << std::endl; } }; // inherit EvBase directly struct Ev1 : EvBase<Ev1> {}; struct Ev2 : EvBase<Ev2> {}; struct Ev3 : EvBase<Ev3> {}; // inherit EvBase indirectly template<class MostDerived> struct EvIntermediate : EvBase<MostDerived> {}; struct Ev4 : EvIntermediate<Ev4> {}; When I run the application, I see that at some stage the counter goes negative, and its tendency is to get more and more negative. I guess I don't realize something important about the sc::event, so I'd appreciate enlightment on this. Thanks, Igor'.