Function cancel

include/boost/asio/basic_file.hpp:747–752

        "or earlier. Consult documentation for details."))
#endif
  void cancel()
  {
    boost::system::error_code ec;
    impl_.get_service().cancel(impl_.get_implementation(), ec);
    boost::asio::detail::throw_error(ec, "cancel");
  }

  /// Cancel all asynchronous operations associated with the file.
  /**