/wj9012/p/3876734.html
一个tcp的客户端服务器程序
服务器端不变，客户端通过I/O复用轮询键盘输入与socket输入（接收客户端的信息）
服务器端：
1 /*服务器: 2 1.客户端关闭后，服务器再向客户端发送信息，第一次会收到一个RST复位报文，第二次会收到SIGPIPE信号，导致服务器关闭，必须对这个信号进行处理： 31.在服务器对read返回值为0的情况进行处理，不向客户端发送信息 42.signal函数: signal(SIGPIPE, handle) 或者直接忽略signal(SIGPIPE, SIG_IGN) 5 */ 6 #include <stdio.h> 7 #include <stdlib.h> 8 #include <string.h> 9 #include <unistd.h>10 #include <errno.h>11 #include <sys/types.h>12 #include <sys/stat.h>13 #include <sys/socket.h>14 #include <arpa/inet.h>15 #include <signal.h>16 17 #define ERR_EXIT(m) \18do { \19 perror(m);\20 exit(EXIT_FAILURE);\21}while(0)//宏定义的错误处理22 23 static void do_service(int fd)24 {25char recvbuf[1024] = {0};26int ret;27while(1)28{29 memset(recvbuf, 0, sizeof recvbuf);30 ret = read(&rt, recvbuf, 1024);31 sleep(3);32 if(ret == 0)//关闭客户端时会导致ret== 033 printf("no message\n");34 else if(ret == -1)35 {36 if(errno == EINTR)37 continue;38 return ;39 } 40 rio_writen(fd, recvbuf, 5);41}42 }43 44 void handle(int signum)//SIGPIPE信号处理函数45 {46 printf("hello\n");47 }48 49 int main(int argc, const char *argv[])50 {51if(signal(SIGPIPE, handle) == SIG_ERR)52 ERR_EXIT("signal"); 53 54int listenfd = socket(AF_INET, SOCK_STREAM, 0);//准备一个socketfd55if(listenfd == -1 )56 ERR_EXIT("listen");57 58int on = 1;59if(setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1)//setsockopt设置端口复用60{61 close(listenfd);62 ERR_EXIT("setsockopt");63}64 65struct sockaddr_in seraddr;66seraddr.sin_family = AF_INET;67seraddr.sin_port = htons(8888);68seraddr.sin_addr.s_addr = htonl(INADDR_ANY);69socklen_t len = sizeof(seraddr);70if(bind(listenfd, (struct sockaddr*)&seraddr, len) == -1)//监听socket端口，71{72 close(listenfd);73 ERR_EXIT("bind");74}75//上述过程可以封装到起来，不用全部写入main76if(listen(listenfd, 6) == -1)77{78 close(listenfd);79 ERR_EXIT("listen");80}81 82struct sockaddr_in cliaddr;83bzero(&cliaddr, sizeof(cliaddr));84socklen_t cli_len = sizeof cliaddr;85 86int clientfd;87clientfd = accept(listenfd, (struct sockaddr*)&cliaddr, &cli_len);88 89if(clientfd == -1) 90{91 close(listenfd);92 ERR_EXIT("accept");93}94do_service(clientfd);95 96close(clientfd);97close(listenfd);98return 0;99 }
1.select客户端:
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <string.h> 4 #include <errno.h> 5 #include <sys/types.h> 6 #include <sys/socket.h> 7 #include <netinet/in.h> 8 #include <arpa/inet.h> 9 #include <sys/select.h>10 11 #define ERR_EXIT(m) \12do { \13 perror(m);\14 exit(EXIT_FAILURE);\15}while(0)16 17 static void do_client(int fd)18 {19char recvbuf[MAXLINE + 1] = {0};20char sendbuf[MAXLINE + 1] = {0};21 22fd_set reade, ready;//将ready集合放入select轮询，每次轮询前将reade赋值给ready23FD_ZERO(&reade);//清空reade集合24int fd_stdin = fileno(stdin);25FD_SET(fd_stdin, &reade);26FD_SET(fd, &reade);//将需要监听的文件描述符加入集合27int fd_max = (fd_stdin > fd) ? fd_stdin : fd;//select轮询的最大文件描述符28 29int ret;30while(1)31{32 ready = reade;33 ret = select( fd_max+1, &ready, NULL, NULL, NULL);//轮询，最后一个参数struct *timeval设置为NULL表示即时轮询（每次轮询间没时间间隔）34 if(ret < 0)35 {36 if(errno == EINTR)37 continue;38 ERR_EXIT("select");39 }else if(ret == 0)//监听的文件描述符状态未发生变化40 {41 continue;42 }43 44 if(FD_ISSET(fd_stdin, &ready))45 {46 if(fgets(sendbuf, sizeof(sendbuf), stdin) == NULL)47 {48 shutdown(fd, SHUT_WR);//关闭fd的写端，close关闭时关闭整个描述符,若再写的话会导致write返回-1，系统会向客户端进程发送一个SIGPIPE信号，
导致关闭，可以对信号进行signal(SIGPIPE, SIG_IGN)处理，也可将fd_stdin从监听队列删除49// close(fd);50 exit(EXIT_SUCCESS);51//break;
52 }else53 write(fd, sendbuf, strlen(sendbuf)); 54 }55 56 if(FD_ISSET(fd, &ready))57 {58 int nread = read(fd, recvbuf, MAXLINE);59 if(nread < 0)60 ERR_EXIT("read");61 if(nread == 0)//如果没接收到消息，打印关闭描述符，退出循环62 {63 fprintf(stdout, "fd close\n");64 break;65 }66 fprintf(stdout, "receive:%s\n", recvbuf);//注意要刷新67 }68 memset(recvbuf, 0, sizeof recvbuf);69 memset(sendbuf, 0, sizeof sendbuf);70}71 }72 73 int main(int argc, const char *argv[])74 {75int fd = socket(AF_INET, SOCK_STREAM, 0);76if(fd < 0)77 ERR_EXIT("socket");78 79struct sockaddr_in cliaddr;80cliaddr.sin_family = AF_INET;81cliaddr.sin_port = htons(8888);82cliaddr.sin_addr.s_addr = inet_addr("127.0.0.1");83socklen_t len = sizeof cliaddr;84 85int ret ;86if((ret = connect(fd, (struct sockaddr*)&cliaddr, len)) == -1)87{88 close(fd);89 ERR_EXIT("connect");90}91do_client(fd);92close(fd);93printf("123\n");94return 0;95 }
2.poll客户端：
//其余部分和select中一样
3.epoll客户端
