[exec.recv.concepts] (original) (raw)

A receiver represents the continuation of an asynchronous operation.

The receiver concept defines the requirements for a receiver type ([exec.async.ops]).

The receiver_of concept defines the requirements for a receiver type that is usable as the first argument of a set of completion operations corresponding to a set of completion signatures.

The get_env customization point object is used to access a receiver's associated environment.

namespace std::execution { template<class Rcvr> concept receiver = derived_from<typename remove_cvref_t<Rcvr>::receiver_concept, receiver_t> && requires(const remove_cvref_t<Rcvr>& rcvr) { { get_env(rcvr) } -> queryable;} && move_constructible<remove_cvref_t<Rcvr>> && constructible_from<remove_cvref_t<Rcvr>, Rcvr>; template<class Signature, class Rcvr> concept valid-completion-for = requires (Signature* sig) { []<class Tag, class... Args>(Tag(*)(Args...)) requires callable<Tag, remove_cvref_t<Rcvr>, Args...> {}(sig);};template<class Rcvr, class Completions> concept has-completions = requires (Completions* completions) { []<valid-completion-for<Rcvr>...Sigs>(completion_signatures<Sigs...>*) {}(completions);};template<class Rcvr, class Completions> concept receiver_of = receiver<Rcvr> && has-completions<Rcvr, Completions>;}