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

void handler(const boost::system::error_code &ec) 
{ 
  std::cout << "5 s." << std::endl; 
} 

int main() 
{ 
  boost::asio::io_service io_service; 
  boost::asio::deadline_timer timer(io_service, 
    boost::posix_time::seconds(5)); 
  timer.async_wait(handler); 
  io_service.run(); 
}