跟着 http://www.boost.org/doc/libs/1_53_0/doc/html/boost_asio/tutorial.html 学习asio。
编译的时候需要加上 -lboost_
system
同步定时器
例子
class="c++" name="code">
#include <iostream>
#include <boost/asio.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
using namespace std;
void tuttimer1()
{
boost::asio::io_service io;
// 等待5秒
boost::asio::deadline_timer t(io, boost::posix_time::seconds(5));
t.wait();
}
int main() {
tuttimer1();
cout << "!!!Hello World!!!" << endl; // prints !!!Hello World!!!
return 0;
}
异步定时器例子
#include <iostream>
#include <boost/asio.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
// 定义回调函数,asio库要求回调函数只能有一个参数,且为 const boost::system::error_code & 类型
void print(const boost::system::error_code& /*e*/) {
cout << "This is asynchronous timer!" << endl;
}
void tuttimer2()
{
boost::asio::io_service io;
boost::asio::deadline_timer t(io, boost::posix_time::seconds(5));
cout << "asynchronous timer start!" << endl;
t.async_wait(&print); // 异步等待,传入回调函数,立即返回
cout << "asynchronous timer processing!" << endl;
io.run(); // 很重要!异步IO必须。如果不调用run(),
// 虽然操作被异步执行了,但没有一个等待它完成的机制,回调函数将得不到执行机会。
cout << "asynchronous timer end!" << endl;
}
int main() {
tuttimer2();
return 0;
}
/*
运行结果:
asynchronous timer start!
asynchronous timer processing!
This is asynchronous timer!
asynchronous timer end!
*/
异步定时器使用bind
#include <iostream>
#include <boost/asio.hpp>
#include <boost/date_time/posix_time/posix_time.hpp>
#include <boost/bind.hpp>
void print1(const boost::system::error_code& /*e*/,
boost::asio::deadline_timer* t, int* count)
{
if (*count < 5)
{
cout << *count << "\n" << endl;
++(*count);
t->expires_at(t->expires_at() + boost::posix_time::seconds(1));
t->async_wait(boost::bind(print1, boost::asio::placeholders::error, t, count));
}
}
void tuttimer3()
{
boost::asio::io_service io;
int count = 0;
boost::asio::deadline_timer t(io, boost::posix_time::seconds(1));
t.async_wait(boost::bind(print1, boost::asio::placeholders::error, &t, &count));
io.run();
cout << "Final count is " << count << "\n" << endl;
}
int main() {
tuttimer3();
return 0;
}
/*
运行结果:
0
1
2
3
4
Final count is 5
*/