| Home | Libraries | People | FAQ | More

# Daytime.2 - A synchronous TCP daytime server

This tutorial program shows how to use asio to implement a server application with TCP.

    #include <ctime>
    #include <iostream>
    #include <string>
    #include <boost/asio.hpp>

    using boost::asio::ip::tcp;

We define the function `make_daytime_string()` to create the string to be sent back to the client. This function will be reused in all of our daytime server applications.

    std::string make_daytime_string()
    {
      using namespace std; // For time_t, time and ctime;
      time_t now = time(0);
      return ctime(&now);
    }

    int main()
    {
      try
      {
        boost::asio::io_service io_service;

A boost::asio::ip::tcp::acceptor object needs to be created to listen for new connections. It is initialised to listen on TCP port 13, for IP version 4.

        tcp::acceptor acceptor(io_service, tcp::endpoint(tcp::v4(), 13));

This is an iterative server, which means that it will handle one connection at a time. Create a socket that will represent the connection to the client, and then wait for a connection.

        for (;;)
        {
          tcp::socket socket(io_service);
          acceptor.accept(socket);

A client is accessing our service. Determine the current time and transfer this information to the client.

          std::string message = make_daytime_string();

          boost::asio::write(socket, boost::asio::buffer(message),
              boost::asio::transfer_all(), boost::asio::ignore_error());
        }
      }

Finally, handle any exceptions.

      catch (std::exception& e)
      {
        std::cerr << e.what() << std::endl;
      }

      return 0;
    }

See the full source listing
Return to the tutorial index
Previous: Daytime.1 - A synchronous TCP daytime client
Next: Daytime.3 - An asynchronous TCP daytime server

| Copyright © 2003 - 2006 Christopher M. Kohlhoff