std::ostream& operator<<(std::ostream& o, const ARDOUR::ListenPosition& sf);
std::ostream& operator<<(std::ostream& o, const ARDOUR::LayerModel& sf);
std::ostream& operator<<(std::ostream& o, const ARDOUR::InsertMergePolicy& sf);
std::ostream& operator<<(std::ostream& o, const ARDOUR::ListenPosition& sf);
std::ostream& operator<<(std::ostream& o, const ARDOUR::LayerModel& sf);
std::ostream& operator<<(std::ostream& o, const ARDOUR::InsertMergePolicy& sf);