基于select模型的udp客户端实现超时重传机制

 1 int maxfdp,sockfd;
 2 fd_set fds;
 3 struct timeval timeout;
 4 int interval = 3;
 5 
 6 while (1) {
 7 
 8     timeout.tv_usec = 0;
 9     timeout.tv_sec = interval;
10 
11     FD_ZERO(&fds);
12     FD_SET(sockfd, &fds);
13     maxfdp = sockfd + 1;
14     sendto();
15 
16     switch(select(maxfdp, &fds, NULL, NULL, &timeout)) {
17         case -1:
18                     exit(-1);
19                     break;
20         
21          case 0:
22                     break;
23     
24          default:
25                     if(FD_ISSET(fd, &fds)) {
26                         revcfrom();
27                     }
28                     break;
29      }
30 }