boost 定时器.

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

int main()
{
    boost::asio::io_service io;
    boost::asio::deadline_timer timer(io, boost::posix_time::seconds(3));

    timer.wait();
    std::cout << "Hello, world!
";

    return 0;
}

再来个异步的:

void print(const boost::system::error_code& /*e*/)
{
    std::cout << "Hello, world!
";
}
int main()
{
    boost::asio::io_service io;
    boost::asio::deadline_timer timer(io, boost::posix_time::seconds(5));

    timer.async_wait(&print);
    io.run();

    return 0;
}

上次演示了基本用法,但它只能发生一次.

问题是怎么定义一个重复发生的定时器(就是隔一定的时间它就会发生一次.)呢,下面的代码就是了, 关键在于回调函数中更改了延时不断的延长定时器 

void print(const boost::system::error_code& e,
           boost::asio::deadline_timer* t)
{
  cout<<"ddd"<<endl;
  t->expires_at(t->expires_at()+ boost::posix_time::seconds(1));
  t->async_wait(boost::bind(print,boost::asio::placeholders::error,t));
}

void test1()
{
   boost::asio::io_service io;
   boost::asio::deadline_timer t(io, boost::posix_time::seconds(1));
   t.async_wait(boost::bind(print,boost::asio::placeholders::error,&t));
   io.run();
}

int _tmain(int argc, _TCHAR* argv[])
{
  test1();
  system("pause");
  return 0;
}