### handler_type

(Deprecated: Use two-parameter version of `async_result`.) Default handler type traits provided for all completion token types.

    template<
        typename CompletionToken,
        typename Signature,
        typename  = void>
    struct handler_type

##### Types

Name | Description
--- | ---
type | The handler type for the specific signature.

The `handler_type` traits class is used for determining the concrete handler type to be used for an asynchronous operation. It allows the handler type to be determined at the point where the specific completion handler signature is known.

This template may be specialised for user-defined completion token types.

##### Requirements

Header: `asio/handler_type.hpp`

Convenience header: `asio.hpp`