Disconnect this slot and block the calling thread pending the completion of signals being emitted on the signaler by any other threads. If the slot was already disconnected, this function has no effect on the slot. Throws nothing. The behavior is undefined if this function is called from a slot on the same signaler. Note that it is guaranteed that this slot will not be called by a signal on the same signaler that begins after this function completes, whether wait is true or not.