namespace std { namespace experimental { namespace net { inline namespace v1 { struct executor_arg_t { }; constexpr executor_arg_t executor_arg = executor_arg_t(); } // inline namespace v1 } // namespace net } // namespace experimental } // namespace std
The executor_arg_t struct is an empty structure type used as a unique type to disambiguate constructor and function overloading. Specifically, types may have constructors with executor_arg_t as the first argument, immediately followed by an argument of a type that satisfies the Executor requirements ([async.reqmts.executor]).