https://blog.csdn.net/lianghe_work/article/details/46535859
想詳細徹底地了解poll或看懂下面的代碼請參考《Linux網絡編程——I/O復用之poll函數》
代碼:
- int main(int argc, char *argv[])
- {
- //1.創建tcp監聽套接字
- int sockfd = socket(AF_INET, SOCK_STREAM, 0);
- //2.綁定sockfd
- struct sockaddr_in my_addr;
- bzero(&my_addr, sizeof(my_addr));
- my_addr.sin_family = AF_INET;
- my_addr.sin_port = htons(8000);
- my_addr.sin_addr.s_addr = htonl(INADDR_ANY);
- bind(sockfd, (struct sockaddr *)&my_addr, sizeof(my_addr));
- //3.監聽listen
- listen(sockfd, 10);
- //4.poll相應參數準備
- struct pollfd client[OPEN_MAX];
- int i = 0, maxi = 0;
- for(;i<OPEN_MAX; i++)
- client[i].fd = -1;//初始化poll結構中的文件描述符fd
- client[0].fd = sockfd;//需要監測的描述符
- client[0].events = POLLIN;//普通或優先級帶數據可讀
- //5.對已連接的客戶端的數據處理
- while(1)
- {
- int ret = poll(client, maxi+1, -1);//對加入poll結構體數組所有元素進行監測
- //5.1監測sockfd(監聽套接字)是否存在連接
- if((client[0].revents & POLLIN) == POLLIN )
- {
- struct sockaddr_in cli_addr;
- int clilen = sizeof(cli_addr);
- int connfd = 0;
- //5.1.1 從tcp完成連接中提取客戶端
- connfd = accept(sockfd, (struct sockaddr *)&cli_addr, &clilen);
- //5.1.2 將提取到的connfd放入poll結構體數組中,以便于poll函數監測
- for(i=1; i<OPEN_MAX; i++)
- {
- if(client[i].fd < 0)
- {
- client[i].fd = connfd;
- client[i].events = POLLIN;
- break;
- }
- }
- //5.1.3 maxi更新
- if(i > maxi)
- maxi = i;
- //5.1.4 如果沒有就緒的描述符,就繼續poll監測,否則繼續向下看
- if(--ret <= 0)
- continue;
- }
- //5.2繼續響應就緒的描述符
- for(i=1; i<=maxi; i++)
- {
- if(client[i].fd < 0)
- continue;
- if(client[i].revents & (POLLIN | POLLERR))
- {
- int len = 0;
- char buf[128] = "";
- //5.2.1接受客戶端數據
- if((len = recv(client[i].fd, buf, sizeof(buf), 0)) < 0)
- {
- if(errno == ECONNRESET)//tcp連接超時、RST
- {
- close(client[i].fd);
- client[i].fd = -1;
- }
- else
- perror("read error:");
- }
- else if(len == 0)//客戶端關閉連接
- {
- close(client[i].fd);
- client[i].fd = -1;
- }
- else//正常接收到服務器的數據
- send(client[i].fd, buf, len, 0);
- //5.2.2所有的就緒描述符處理完了,就退出當前的for循環,繼續poll監測
- if(--ret <= 0)
- break;
- }
- }
- }
- return 0;
- }
運行結果: