co_usb::detail::ErrorProtocol Concept Reference

Result protocol for signaling error via error code or full completion. More...

#include <error_protocol.hpp>

Concept definition

template<typename Ty, typename ValTy>
concept co_usb::detail::ErrorProtocol =  requires(Ty errp) {
    typename Ty::template return_type<ValTy>;
    {
        errp.template with_error<ValTy>(std::declval<std::error_code>())
    } -> std::same_as<typename Ty::template return_type<ValTy>>;
    {
        errp.template with_success<ValTy>(std::declval<ValTy>())
    } -> std::same_as<typename Ty::template return_type<ValTy>>;
}

Detailed Description

Result protocol for signaling error via error code or full completion.

Template Parameters

Ty	type of an error protocol
ValTy	type of result value

Uniform protocol that allows the compile-time selection of an error protocol for a wrapper function when a partial result is disallowed.

Guarantees

Error protocol is expected to be transient and be move constructible and assignable. Its destructor is expected to not invoke any meaningful logic.

with_success signals complete success and returns a successful result value. with_error signals error and returns an erronous result value.