用asio的定时器实现带超时的connect，备忘

1. // test.cpp : 定义控制台应用程序的入口点。
2. //
3. #include "stdafx.h"
4. #include <boost/asio.hpp>
5. #include <boost/bind.hpp>
6. #include <boost/date_time/posix_time/posix_time_types.hpp>
7. #include <iostream>
8. using namespace boost::asio;
9. using boost::asio::ip::tcp;
10. class connect_handler
11. {
12. public:
13. connect_handler(io_service& ios)
14. : io_service_(ios),
15. timer_(ios),
16. socket_(ios)
17. {
18. socket_.async_connect(
19. tcp::endpoint(boost::asio::ip::address_v4::loopback(), 3212),
20. boost::bind(&connect_handler::handle_connect, this,
21. boost::asio::placeholders::error));
22. timer_.expires_from_now(boost::posix_time::seconds(5));
23. timer_.async_wait(boost::bind(&connect_handler::close, this));
24. }
25. void handle_connect(const boost::system::error_code& err)
26. {
27. if (err)
28. {
29. std::cout << "Connect error: " << err.message() << "\n";
30. }
31. else
32. {
33. std::cout << "Successful connection\n";
34. }
35. }
36. void close()
37. {
38. socket_.close();
39. }
40. private:
41. io_service& io_service_;
42. deadline_timer timer_;
43. tcp::socket socket_;
44. };
45. int main()
46. {
47. try
48. {
49. io_service ios;
50. tcp::acceptor a(ios, tcp::endpoint(tcp::v4(), 32123), 1);
51. // Make lots of connections so that at least some of them will block.
52. connect_handler ch1(ios);
53. //connect_handler ch2(ios);
54. //connect_handler ch3(ios);
55. //connect_handler ch4(ios);
56. //connect_handler ch5(ios);
57. //connect_handler ch6(ios);
58. //connect_handler ch7(ios);
59. //connect_handler ch8(ios);
60. //connect_handler ch9(ios);
61. ios.run();
62. }
63. catch (std::exception& e)
64. {
65. std::cerr << "Exception: " << e.what() << "\n";
66. }
67. return 0;
68. }