text: //
  // timer.cpp
  // ~~~~~~~~~
  //
  // Copyright (c) 2003-2018 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)
  //
  
  #include <iostream>
  #include <boost/asio.hpp>
  #include <boost/bind.hpp>
  
  void print(const boost::system::error_code& /*e*/,
      boost::asio::steady_timer* t, int* count)
  {
    if (*count < 5)
    {
      std::cout << *count << std::endl;
      ++(*count);
  
      t->expires_at(t->expiry() + boost::asio::chrono::seconds(1));
      t->async_wait(boost::bind(print,
            boost::asio::placeholders::error, t, count));
    }
  }
  
  int main()
  {
    boost::asio::io_context io;
  
    int count = 0;
    boost::asio::steady_timer t(io, boost::asio::chrono::seconds(1));
    t.async_wait(boost::bind(print,
          boost::asio::placeholders::error, &t, &count));
  
    io.run();
  
    std::cout << "Final count is " << count << std::endl;
  
    return 0;
  }
  