Boost asio 同步連接超時設置失敗

場景

        boost庫中的asio模塊，在阻塞模式下，調用connect進行服務器的連接，如果服務器沒有打開，默認情況下需要20秒的超時連接，才會返回。目前嘗試設置套接字的連接超時時間，都不奏效。估計只能修改boost源碼中的超時時間

//設置成非阻塞，然后調用select等待超時，無效
int TestBoostAsioConnectTimeout()
{
 boost::asio::io_service ios;
 boost::asio::ip::tcp::socket sock(ios);
 boost::system::error_code ec;

 sock.open(boost::asio::ip::tcp::v4());
 // 設為非阻塞 
 sock.io_control(boost::asio::ip::tcp::socket::non_blocking_io(true));
 sock.connect(
  boost::asio::ip::tcp::endpoint(
   boost::asio::ip::address::from_string("192.168.1.1"), 80)
  , ec);
 fd_set fdWrite;
 FD_ZERO(&fdWrite);
 FD_SET(sock.native(), &fdWrite);
 timeval tv = { 5 };    // 5秒超時 
 if (select(0, NULL, &fdWrite, NULL, &tv) <= 0
  || !FD_ISSET(sock.native(), &fdWrite))
 {
  std::cout << "連接超時" << std::endl;
  sock.close();
  return 0;
 }
 // 設回阻塞 
 sock.io_control(boost::asio::ip::tcp::socket::non_blocking_io(false));
 std::cout << "連接成功" << std::endl;
 sock.close();

 return 0;
}

//獲取原始的套接字，進行屬性的設置

int TestBoostAsioConnectOverTime()
{
 boost::asio::io_service ios;
 boost::asio::ip::tcp::socket sock(ios);
 boost::system::error_code ec;

 sock.open(boost::asio::ip::tcp::v4());
 // 設為非阻塞 
 sock.io_control(boost::asio::ip::tcp::socket::non_blocking_io(true));
 int timeout = 3000;
 int nRet = setsockopt(sock.native(), SOL_SOCKET, SO_CONNECT_TIME, (const char*)&timeout, sizeof(timeout));
 nRet = setsockopt(sock.native(), SOL_SOCKET, SO_RCVTIMEO, (const char*)&timeout, sizeof(timeout));
 sock.connect(
  boost::asio::ip::tcp::endpoint(
   boost::asio::ip::address::from_string("192.168.1.1"), 80)
  , ec);
 fd_set fdWrite;
 FD_ZERO(&fdWrite);
 FD_SET(sock.native(), &fdWrite);
 timeval tv;
 tv.tv_sec = 1;   // 5秒超時
 tv.tv_usec = 0;
 if (select(0, NULL, &fdWrite, NULL, &tv) <= 0
  || !FD_ISSET(sock.native(), &fdWrite))
 {
  std::cout << "超時/出錯啦" << std::endl;
  sock.close();
  return 0;
 }
 // 設回阻塞 
 sock.io_control(boost::asio::ip::tcp::socket::non_blocking_io(false));
 std::cout << "連接成功" << std::endl;
 sock.close();

 return 0;
}

設置超時的代碼：
windows:
 int nTvlen=1000;  //1s
 int retOpt=setsockopt(m_Socket,SOL_SOCKET, SO_RCVTIMEO, (const char*)&nTvlen,sizeof(nTvlen));
linux:
 struct timeval nTvlen={1,0}; //1S
 int retOpt=setsockopt(m_Socket,SOL_SOCKET, SO_RCVTIMEO, (const char*)&nTvlen,sizeof(nTvlen));