Another update: I've added tracking similar to what I described before. It now passes the random_signal_test except for the final connection count check, which may be a result of the different signal and connection lifetime control I had to use. I ran it with 20 initial signals, a deletion probability of 0.5 and 10000 iterations and it never called a slot with a dead tracked weak_ptr, which is what we want. It also cleans up those slots for each connect() call. The tracking functionality is still somewhat ugly and its per- formance is horrible, but I think it's a starting point. The signals::tracked<...> wrapper template currently only offers implicit conversion to a shared_ptr, which won't enable binding a pointer to member function to it, so it probably needs a full smart pointer interface. I've also thought about the use of recursive_mutex. I could be turned into a normal mutex if the implementation would unlock it before each slot call and lock it again after that. Regards Timmo Stange