slick-orderbook/api/conceptslick_1_1orderbook_1_1OrderBookObserver.html

template<typename T>

concept slick::orderbook::OrderBookObserver =  requires(T observer,

                                     const PriceLevelUpdate& level_update,

                                     const OrderUpdate& order_update,

                                     const Trade& trade,

                                     const TopOfBook& tob) {

    { observer.onPriceLevelUpdate(level_update) } -> std::same_as<void>;

    { observer.onOrderUpdate(order_update) } -> std::same_as<void>;

    { observer.onTrade(trade) } -> std::same_as<void>;

    { observer.onTopOfBookUpdate(tob) } -> std::same_as<void>;

}

slick::orderbook::OrderBookObserver
Concept for orderbook observers Observers must implement all four callback methods.
Definition concepts.hpp:22