13 Asynchronous model [async]

13.11 uses_executor [async.uses.executor]

13.11.1 uses_executor trait [async.uses.executor.trait]

namespace std {
namespace experimental {
namespace net {
inline namespace v1 {

  template<class T, class Executor> struct uses_executor;

} // inline namespace v1
} // namespace net
} // namespace experimental
} // namespace std
1

Remark: Detects whether T has a nested executor_type that is convertible from Executor. Meets the BinaryTypeTrait requirements (C++ 2014 [meta.rqmts]). The implementation provides a definition that is derived from true_type if the qualified-id T::executor_type is valid and denotes a type and is_convertible<Executor, T::executor_type>::value != false, otherwise it is derived from false_type. A program may specialize this template to derive from true_type for a user-defined type T that does not have a nested executor_type but nonetheless can be constructed with an executor if the first argument of a constructor has type executor_arg_t and the second argument has type Executor.

13.11.2 uses-executor construction [async.uses.executor.cons]

1

Uses-executor construction with executor Executor refers to the construction of an object obj of type T, using constructor arguments v1, v2, ..., vN of types V1, V2, ..., VN, respectively, and an executor ex of type Executor, according to the following rules:

  • (1.1)

    if uses_executor_v<T, Executor> is true and is_constructible<T, executor_arg_t, Executor, V1, V2, ..., VN>::value is true, then obj is initialized as obj(executor_arg, ex, v1, v2, ..., vN);

  • (1.2)

    otherwise, obj is initialized as obj(v1, v2, ..., vN).