text: //
  // basic_socket_acceptor.hpp
  // ~~~~~~~~~~~~~~~~~~~~~~~~~
  //
  // Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com)
  //
  // Distributed under the Boost Software License, Version 1.0. (See accompanying
  // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  //
  
  #ifndef BOOST_ASIO_BASIC_SOCKET_ACCEPTOR_HPP
  #define BOOST_ASIO_BASIC_SOCKET_ACCEPTOR_HPP
  
  #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  # pragma once
  #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  
  #include <boost/asio/detail/push_options.hpp>
  
  #include <boost/asio/basic_io_object.hpp>
  #include <boost/asio/basic_socket.hpp>
  #include <boost/asio/error.hpp>
  #include <boost/asio/socket_acceptor_service.hpp>
  #include <boost/asio/socket_base.hpp>
  #include <boost/asio/detail/throw_error.hpp>
  
  namespace boost {
  namespace asio {
  
  /// Provides the ability to accept new connections.
  /**
   * The basic_socket_acceptor class template is used for accepting new socket
   * connections.
   *
   * @par Thread Safety
   * @e Distinct @e objects: Safe.@n
   * @e Shared @e objects: Unsafe.
   *
   * @par Example
   * Opening a socket acceptor with the SO_REUSEADDR option enabled:
   * @code
   * boost::asio::ip::tcp::acceptor acceptor(io_service);
   * boost::asio::ip::tcp::endpoint endpoint(boost::asio::ip::tcp::v4(), port);
   * acceptor.open(endpoint.protocol());
   * acceptor.set_option(boost::asio::ip::tcp::acceptor::reuse_address(true));
   * acceptor.bind(endpoint);
   * acceptor.listen();
   * @endcode
   */
  template <typename Protocol,
      typename SocketAcceptorService = socket_acceptor_service<Protocol> >
  class basic_socket_acceptor
    : public basic_io_object<SocketAcceptorService>,
      public socket_base
  {
  public:
    /// The native representation of an acceptor.
    typedef typename SocketAcceptorService::native_type native_type;
  
    /// The protocol type.
    typedef Protocol protocol_type;
  
    /// The endpoint type.
    typedef typename Protocol::endpoint endpoint_type;
  
    /// Construct an acceptor without opening it.
    /**
     * This constructor creates an acceptor without opening it to listen for new
     * connections. The open() function must be called before the acceptor can
     * accept new socket connections.
     *
     * @param io_service The io_service object that the acceptor will use to
     * dispatch handlers for any asynchronous operations performed on the
     * acceptor.
     */
    explicit basic_socket_acceptor(boost::asio::io_service& io_service)
      : basic_io_object<SocketAcceptorService>(io_service)
    {
    }
  
    /// Construct an open acceptor.
    /**
     * This constructor creates an acceptor and automatically opens it.
     *
     * @param io_service The io_service object that the acceptor will use to
     * dispatch handlers for any asynchronous operations performed on the
     * acceptor.
     *
     * @param protocol An object specifying protocol parameters to be used.
     *
     * @throws boost::system::system_error Thrown on failure.
     */
    basic_socket_acceptor(boost::asio::io_service& io_service,
        const protocol_type& protocol)
      : basic_io_object<SocketAcceptorService>(io_service)
    {
      boost::system::error_code ec;
      this->service.open(this->implementation, protocol, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Construct an acceptor opened on the given endpoint.
    /**
     * This constructor creates an acceptor and automatically opens it to listen
     * for new connections on the specified endpoint.
     *
     * @param io_service The io_service object that the acceptor will use to
     * dispatch handlers for any asynchronous operations performed on the
     * acceptor.
     *
     * @param endpoint An endpoint on the local machine on which the acceptor
     * will listen for new connections.
     *
     * @param reuse_addr Whether the constructor should set the socket option
     * socket_base::reuse_address.
     *
     * @throws boost::system::system_error Thrown on failure.
     *
     * @note This constructor is equivalent to the following code:
     * @code
     * basic_socket_acceptor<Protocol> acceptor(io_service);
     * acceptor.open(endpoint.protocol());
     * if (reuse_addr)
     *   acceptor.set_option(socket_base::reuse_address(true));
     * acceptor.bind(endpoint);
     * acceptor.listen(listen_backlog);
     * @endcode
     */
    basic_socket_acceptor(boost::asio::io_service& io_service,
        const endpoint_type& endpoint, bool reuse_addr = true)
      : basic_io_object<SocketAcceptorService>(io_service)
    {
      boost::system::error_code ec;
      this->service.open(this->implementation, endpoint.protocol(), ec);
      boost::asio::detail::throw_error(ec);
      if (reuse_addr)
      {
        this->service.set_option(this->implementation,
            socket_base::reuse_address(true), ec);
        boost::asio::detail::throw_error(ec);
      }
      this->service.bind(this->implementation, endpoint, ec);
      boost::asio::detail::throw_error(ec);
      this->service.listen(this->implementation,
          socket_base::max_connections, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Construct a basic_socket_acceptor on an existing native acceptor.
    /**
     * This constructor creates an acceptor object to hold an existing native
     * acceptor.
     *
     * @param io_service The io_service object that the acceptor will use to
     * dispatch handlers for any asynchronous operations performed on the
     * acceptor.
     *
     * @param protocol An object specifying protocol parameters to be used.
     *
     * @param native_acceptor A native acceptor.
     *
     * @throws boost::system::system_error Thrown on failure.
     */
    basic_socket_acceptor(boost::asio::io_service& io_service,
        const protocol_type& protocol, const native_type& native_acceptor)
      : basic_io_object<SocketAcceptorService>(io_service)
    {
      boost::system::error_code ec;
      this->service.assign(this->implementation, protocol, native_acceptor, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Open the acceptor using the specified protocol.
    /**
     * This function opens the socket acceptor so that it will use the specified
     * protocol.
     *
     * @param protocol An object specifying which protocol is to be used.
     *
     * @throws boost::system::system_error Thrown on failure.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * acceptor.open(boost::asio::ip::tcp::v4());
     * @endcode
     */
    void open(const protocol_type& protocol = protocol_type())
    {
      boost::system::error_code ec;
      this->service.open(this->implementation, protocol, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Open the acceptor using the specified protocol.
    /**
     * This function opens the socket acceptor so that it will use the specified
     * protocol.
     *
     * @param protocol An object specifying which protocol is to be used.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * boost::system::error_code ec;
     * acceptor.open(boost::asio::ip::tcp::v4(), ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * @endcode
     */
    boost::system::error_code open(const protocol_type& protocol,
        boost::system::error_code& ec)
    {
      return this->service.open(this->implementation, protocol, ec);
    }
  
    /// Assigns an existing native acceptor to the acceptor.
    /*
     * This function opens the acceptor to hold an existing native acceptor.
     *
     * @param protocol An object specifying which protocol is to be used.
     *
     * @param native_acceptor A native acceptor.
     *
     * @throws boost::system::system_error Thrown on failure.
     */
    void assign(const protocol_type& protocol, const native_type& native_acceptor)
    {
      boost::system::error_code ec;
      this->service.assign(this->implementation, protocol, native_acceptor, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Assigns an existing native acceptor to the acceptor.
    /*
     * This function opens the acceptor to hold an existing native acceptor.
     *
     * @param protocol An object specifying which protocol is to be used.
     *
     * @param native_acceptor A native acceptor.
     *
     * @param ec Set to indicate what error occurred, if any.
     */
    boost::system::error_code assign(const protocol_type& protocol,
        const native_type& native_acceptor, boost::system::error_code& ec)
    {
      return this->service.assign(this->implementation,
          protocol, native_acceptor, ec);
    }
  
    /// Determine whether the acceptor is open.
    bool is_open() const
    {
      return this->service.is_open(this->implementation);
    }
  
    /// Bind the acceptor to the given local endpoint.
    /**
     * This function binds the socket acceptor to the specified endpoint on the
     * local machine.
     *
     * @param endpoint An endpoint on the local machine to which the socket
     * acceptor will be bound.
     *
     * @throws boost::system::system_error Thrown on failure.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * acceptor.open(boost::asio::ip::tcp::v4());
     * acceptor.bind(boost::asio::ip::tcp::endpoint(12345));
     * @endcode
     */
    void bind(const endpoint_type& endpoint)
    {
      boost::system::error_code ec;
      this->service.bind(this->implementation, endpoint, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Bind the acceptor to the given local endpoint.
    /**
     * This function binds the socket acceptor to the specified endpoint on the
     * local machine.
     *
     * @param endpoint An endpoint on the local machine to which the socket
     * acceptor will be bound.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * acceptor.open(boost::asio::ip::tcp::v4());
     * boost::system::error_code ec;
     * acceptor.bind(boost::asio::ip::tcp::endpoint(12345), ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * @endcode
     */
    boost::system::error_code bind(const endpoint_type& endpoint,
        boost::system::error_code& ec)
    {
      return this->service.bind(this->implementation, endpoint, ec);
    }
  
    /// Place the acceptor into the state where it will listen for new
    /// connections.
    /**
     * This function puts the socket acceptor into the state where it may accept
     * new connections.
     *
     * @param backlog The maximum length of the queue of pending connections.
     *
     * @throws boost::system::system_error Thrown on failure.
     */
    void listen(int backlog = socket_base::max_connections)
    {
      boost::system::error_code ec;
      this->service.listen(this->implementation, backlog, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Place the acceptor into the state where it will listen for new
    /// connections.
    /**
     * This function puts the socket acceptor into the state where it may accept
     * new connections.
     *
     * @param backlog The maximum length of the queue of pending connections.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::system::error_code ec;
     * acceptor.listen(boost::asio::socket_base::max_connections, ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * @endcode
     */
    boost::system::error_code listen(int backlog, boost::system::error_code& ec)
    {
      return this->service.listen(this->implementation, backlog, ec);
    }
  
    /// Close the acceptor.
    /**
     * This function is used to close the acceptor. Any asynchronous accept
     * operations will be cancelled immediately.
     *
     * A subsequent call to open() is required before the acceptor can again be
     * used to again perform socket accept operations.
     *
     * @throws boost::system::system_error Thrown on failure.
     */
    void close()
    {
      boost::system::error_code ec;
      this->service.close(this->implementation, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Close the acceptor.
    /**
     * This function is used to close the acceptor. Any asynchronous accept
     * operations will be cancelled immediately.
     *
     * A subsequent call to open() is required before the acceptor can again be
     * used to again perform socket accept operations.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::system::error_code ec;
     * acceptor.close(ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * @endcode
     */
    boost::system::error_code close(boost::system::error_code& ec)
    {
      return this->service.close(this->implementation, ec);
    }
  
    /// Get the native acceptor representation.
    /**
     * This function may be used to obtain the underlying representation of the
     * acceptor. This is intended to allow access to native acceptor functionality
     * that is not otherwise provided.
     */
    native_type native()
    {
      return this->service.native(this->implementation);
    }
  
    /// Cancel all asynchronous operations associated with the acceptor.
    /**
     * This function causes all outstanding asynchronous connect, send and receive
     * operations to finish immediately, and the handlers for cancelled operations
     * will be passed the boost::asio::error::operation_aborted error.
     *
     * @throws boost::system::system_error Thrown on failure.
     */
    void cancel()
    {
      boost::system::error_code ec;
      this->service.cancel(this->implementation, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Cancel all asynchronous operations associated with the acceptor.
    /**
     * This function causes all outstanding asynchronous connect, send and receive
     * operations to finish immediately, and the handlers for cancelled operations
     * will be passed the boost::asio::error::operation_aborted error.
     *
     * @param ec Set to indicate what error occurred, if any.
     */
    boost::system::error_code cancel(boost::system::error_code& ec)
    {
      return this->service.cancel(this->implementation, ec);
    }
  
    /// Set an option on the acceptor.
    /**
     * This function is used to set an option on the acceptor.
     *
     * @param option The new option value to be set on the acceptor.
     *
     * @throws boost::system::system_error Thrown on failure.
     *
     * @sa SettableSocketOption @n
     * boost::asio::socket_base::reuse_address
     * boost::asio::socket_base::enable_connection_aborted
     *
     * @par Example
     * Setting the SOL_SOCKET/SO_REUSEADDR option:
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::acceptor::reuse_address option(true);
     * acceptor.set_option(option);
     * @endcode
     */
    template <typename SettableSocketOption>
    void set_option(const SettableSocketOption& option)
    {
      boost::system::error_code ec;
      this->service.set_option(this->implementation, option, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Set an option on the acceptor.
    /**
     * This function is used to set an option on the acceptor.
     *
     * @param option The new option value to be set on the acceptor.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @sa SettableSocketOption @n
     * boost::asio::socket_base::reuse_address
     * boost::asio::socket_base::enable_connection_aborted
     *
     * @par Example
     * Setting the SOL_SOCKET/SO_REUSEADDR option:
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::acceptor::reuse_address option(true);
     * boost::system::error_code ec;
     * acceptor.set_option(option, ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * @endcode
     */
    template <typename SettableSocketOption>
    boost::system::error_code set_option(const SettableSocketOption& option,
        boost::system::error_code& ec)
    {
      return this->service.set_option(this->implementation, option, ec);
    }
  
    /// Get an option from the acceptor.
    /**
     * This function is used to get the current value of an option on the
     * acceptor.
     *
     * @param option The option value to be obtained from the acceptor.
     *
     * @throws boost::system::system_error Thrown on failure.
     *
     * @sa GettableSocketOption @n
     * boost::asio::socket_base::reuse_address
     *
     * @par Example
     * Getting the value of the SOL_SOCKET/SO_REUSEADDR option:
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::acceptor::reuse_address option;
     * acceptor.get_option(option);
     * bool is_set = option.get();
     * @endcode
     */
    template <typename GettableSocketOption>
    void get_option(GettableSocketOption& option)
    {
      boost::system::error_code ec;
      this->service.get_option(this->implementation, option, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Get an option from the acceptor.
    /**
     * This function is used to get the current value of an option on the
     * acceptor.
     *
     * @param option The option value to be obtained from the acceptor.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @sa GettableSocketOption @n
     * boost::asio::socket_base::reuse_address
     *
     * @par Example
     * Getting the value of the SOL_SOCKET/SO_REUSEADDR option:
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::acceptor::reuse_address option;
     * boost::system::error_code ec;
     * acceptor.get_option(option, ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * bool is_set = option.get();
     * @endcode
     */
    template <typename GettableSocketOption>
    boost::system::error_code get_option(GettableSocketOption& option,
        boost::system::error_code& ec)
    {
      return this->service.get_option(this->implementation, option, ec);
    }
  
    /// Get the local endpoint of the acceptor.
    /**
     * This function is used to obtain the locally bound endpoint of the acceptor.
     *
     * @returns An object that represents the local endpoint of the acceptor.
     *
     * @throws boost::system::system_error Thrown on failure.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::endpoint endpoint = acceptor.local_endpoint();
     * @endcode
     */
    endpoint_type local_endpoint() const
    {
      boost::system::error_code ec;
      endpoint_type ep = this->service.local_endpoint(this->implementation, ec);
      boost::asio::detail::throw_error(ec);
      return ep;
    }
  
    /// Get the local endpoint of the acceptor.
    /**
     * This function is used to obtain the locally bound endpoint of the acceptor.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @returns An object that represents the local endpoint of the acceptor.
     * Returns a default-constructed endpoint object if an error occurred and the
     * error handler did not throw an exception.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::system::error_code ec;
     * boost::asio::ip::tcp::endpoint endpoint = acceptor.local_endpoint(ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * @endcode
     */
    endpoint_type local_endpoint(boost::system::error_code& ec) const
    {
      return this->service.local_endpoint(this->implementation, ec);
    }
  
    /// Accept a new connection.
    /**
     * This function is used to accept a new connection from a peer into the
     * given socket. The function call will block until a new connection has been
     * accepted successfully or an error occurs.
     *
     * @param peer The socket into which the new connection will be accepted.
     *
     * @throws boost::system::system_error Thrown on failure.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::socket socket(io_service);
     * acceptor.accept(socket);
     * @endcode
     */
    template <typename SocketService>
    void accept(basic_socket<protocol_type, SocketService>& peer)
    {
      boost::system::error_code ec;
      this->service.accept(this->implementation, peer, 0, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Accept a new connection.
    /**
     * This function is used to accept a new connection from a peer into the
     * given socket. The function call will block until a new connection has been
     * accepted successfully or an error occurs.
     *
     * @param peer The socket into which the new connection will be accepted.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::soocket socket(io_service);
     * boost::system::error_code ec;
     * acceptor.accept(socket, ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * @endcode
     */
    template <typename SocketService>
    boost::system::error_code accept(
        basic_socket<protocol_type, SocketService>& peer,
        boost::system::error_code& ec)
    {
      return this->service.accept(this->implementation, peer, 0, ec);
    }
  
    /// Start an asynchronous accept.
    /**
     * This function is used to asynchronously accept a new connection into a
     * socket. The function call always returns immediately.
     *
     * @param peer The socket into which the new connection will be accepted.
     * Ownership of the peer object is retained by the caller, which must
     * guarantee that it is valid until the handler is called.
     *
     * @param handler The handler to be called when the accept operation
     * completes. Copies will be made of the handler as required. The function
     * signature of the handler must be:
     * @code void handler(
     *   const boost::system::error_code& error // Result of operation.
     * ); @endcode
     * Regardless of whether the asynchronous operation completes immediately or
     * not, the handler will not be invoked from within this function. Invocation
     * of the handler will be performed in a manner equivalent to using
     * boost::asio::io_service::post().
     *
     * @par Example
     * @code
     * void accept_handler(const boost::system::error_code& error)
     * {
     *   if (!error)
     *   {
     *     // Accept succeeded.
     *   }
     * }
     *
     * ...
     *
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::socket socket(io_service);
     * acceptor.async_accept(socket, accept_handler);
     * @endcode
     */
    template <typename SocketService, typename AcceptHandler>
    void async_accept(basic_socket<protocol_type, SocketService>& peer,
        AcceptHandler handler)
    {
      this->service.async_accept(this->implementation, peer, 0, handler);
    }
  
    /// Accept a new connection and obtain the endpoint of the peer
    /**
     * This function is used to accept a new connection from a peer into the
     * given socket, and additionally provide the endpoint of the remote peer.
     * The function call will block until a new connection has been accepted
     * successfully or an error occurs.
     *
     * @param peer The socket into which the new connection will be accepted.
     *
     * @param peer_endpoint An endpoint object which will receive the endpoint of
     * the remote peer.
     *
     * @throws boost::system::system_error Thrown on failure.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::socket socket(io_service);
     * boost::asio::ip::tcp::endpoint endpoint;
     * acceptor.accept(socket, endpoint);
     * @endcode
     */
    template <typename SocketService>
    void accept(basic_socket<protocol_type, SocketService>& peer,
        endpoint_type& peer_endpoint)
    {
      boost::system::error_code ec;
      this->service.accept(this->implementation, peer, &peer_endpoint, ec);
      boost::asio::detail::throw_error(ec);
    }
  
    /// Accept a new connection and obtain the endpoint of the peer
    /**
     * This function is used to accept a new connection from a peer into the
     * given socket, and additionally provide the endpoint of the remote peer.
     * The function call will block until a new connection has been accepted
     * successfully or an error occurs.
     *
     * @param peer The socket into which the new connection will be accepted.
     *
     * @param peer_endpoint An endpoint object which will receive the endpoint of
     * the remote peer.
     *
     * @param ec Set to indicate what error occurred, if any.
     *
     * @par Example
     * @code
     * boost::asio::ip::tcp::acceptor acceptor(io_service);
     * ...
     * boost::asio::ip::tcp::socket socket(io_service);
     * boost::asio::ip::tcp::endpoint endpoint;
     * boost::system::error_code ec;
     * acceptor.accept(socket, endpoint, ec);
     * if (ec)
     * {
     *   // An error occurred.
     * }
     * @endcode
     */
    template <typename SocketService>
    boost::system::error_code accept(
        basic_socket<protocol_type, SocketService>& peer,
        endpoint_type& peer_endpoint, boost::system::error_code& ec)
    {
      return this->service.accept(this->implementation, peer, &peer_endpoint, ec);
    }
  
    /// Start an asynchronous accept.
    /**
     * This function is used to asynchronously accept a new connection into a
     * socket, and additionally obtain the endpoint of the remote peer. The
     * function call always returns immediately.
     *
     * @param peer The socket into which the new connection will be accepted.
     * Ownership of the peer object is retained by the caller, which must
     * guarantee that it is valid until the handler is called.
     *
     * @param peer_endpoint An endpoint object into which the endpoint of the
     * remote peer will be written. Ownership of the peer_endpoint object is
     * retained by the caller, which must guarantee that it is valid until the
     * handler is called.
     *
     * @param handler The handler to be called when the accept operation
     * completes. Copies will be made of the handler as required. The function
     * signature of the handler must be:
     * @code void handler(
     *   const boost::system::error_code& error // Result of operation.
     * ); @endcode
     * Regardless of whether the asynchronous operation completes immediately or
     * not, the handler will not be invoked from within this function. Invocation
     * of the handler will be performed in a manner equivalent to using
     * boost::asio::io_service::post().
     */
    template <typename SocketService, typename AcceptHandler>
    void async_accept(basic_socket<protocol_type, SocketService>& peer,
        endpoint_type& peer_endpoint, AcceptHandler handler)
    {
      this->service.async_accept(this->implementation,
          peer, &peer_endpoint, handler);
    }
  };
  
  } // namespace asio
  } // namespace boost
  
  #include <boost/asio/detail/pop_options.hpp>
  
  #endif // BOOST_ASIO_BASIC_SOCKET_ACCEPTOR_HPP
  