Christopher Kohlhoff 311d355ab4 Add experimental::as_single completion token adapter. ...

The as_single completion token adapter can be used to specify that the
completion handler arguments should be combined into a single argument.
For completion signatures with a single parameter, the argument is
passed through as-is. For signatures with two or more parameters, the
arguments are combined into a tuple.

The as_single adapter may be used in conjunction with use_awaitable and
structured bindings as follows:

    auto [e, n] = co_await socket.async_read_some(
        boost::asio::buffer(data), as_single(use_awaitable));

Alternatively, it may be used as a default completion token like so:

    using default_token = as_single_t<use_awaitable_t<>>;
    using tcp_socket = default_token::as_default_on_t<tcp::socket>;
    // ...
    awaitable<void> do_read(tcp_socket socket)
    {
      // ...
      auto [e, n] = co_await socket.async_read_some(boost::asio::buffer(data));
      // ...
    }

2020-11-02 14:03:09 +11:00

..

coroutines_ts

Add experimental::as_single completion token adapter.

2020-11-02 14:03:09 +11:00