http://blog.csdn.net/stpeace/article/details/73718836
select
//连接代理服务器
connect(socket, (sockaddr*)&servAddr, sizeof(sockaddr));
FD_ZERO(&r);
FD_SET(socket, &r);
timeout.tv_sec = 5;
timeout.tv_usec =0;
ret = select(0, 0, &r, 0, &timeout);
如果进程句柄超过1024,select很容易崩溃