【BOOST-计时器-同步、异步(boost::asio::deadline_timer)】
//同步定时器;
{
boost::asio::io_service ios;
//所有asio程序必须要有一个io_service对象;
boost::asio::deadline_timer d_timer( ios, boost::posix_time::seconds(2) );
//两秒后定时器终止;
std::cout << d_timer.expires_at() << std::endl;
//查看终止的绝对时间;
d_timer.wait();
//调用wait()同步等待;
std::cout << "Hello asio" << std::endl;
}
//输出函数
void Print( const boost::system::error_code & )
{
std::cout << "Hello asio " << std::endl;
}
//异步定时器;
{
boost::asio::io_service ios;
//所有asio程序必须要有一个io_service对象;
boost::asio::deadline_timer d_timer( ios, boost::posix_time::seconds(2) );
//两秒后定时器终止;
d_timer.async_wait( Print );
std::cout << "it show before timer expired." << std::endl;
ios.run();
}