CompletionToken Interface Reference

#include <ozo/core/concept.h>

Description

Completion token concept.

CompletionToken is an entity which determines how to continue with asynchronous operation result when the operation is complete. According to boost::asio::async_completion it defines the return value of an asynchronous function.

Assume we have an asynchronous IO function:

template <typename ConnectionProvider, typename CompletionToken>
auto async_io(ConnectionProvider&&, Param1 p1, ..., CompletionToken&&);

Then the result type of the function depends on CompletionToken, and CompletionToken - is any of these next entities:

• Handler concept implementation. Asynchronous function in this case will return void. In this case the equivalent function signature will be:

  template <typename ConnectionProvider>
  void async_io(ConnectionProvider, Param1 p1, ..., Handler);

• boost::asio::use_future - to get a future on the asynchronous operation result. Asynchronous function in this case will return std::future<Connection>. In this case the equivalent function signature will be:

  template <typename ConnectionProvider>
  std::future<ozo::connection_type<ConnectionProvider>> async_io(
      ConnectionProvider&&, Param1 p1, ..., boost::asio::use_future_t);

• boost::asio::yield_context - to use async operation with Boost.Coroutine. Asynchronous function in this case will return Connection. In this case the equivalent function signature will be:

  template <typename ConnectionProvider>
  ozo::connection_type<ConnectionProvider> async_io(
      ConnectionProvider&&, Param1 p1, ..., boost::asio::yield_context);

• any other type supported with boost::asio::async_completion mechanism. Asynchronous function in this case will return a type is depends on boost::asio::async_completion::result.