/* myserver.c */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <arpa/inet.h> #include <sys/types.h> #include <sys/socket.h> #include <unistd.h> #include <ctype.h> #define SERV_PORT 6666 #define SERV_IP INADDR_ANY #define MAXLISTENQ 128 void perr_exit(const char * s) { perror(s); exit(1); } int main(void) { int listenfd, connfd; int n; char buf[BUFSIZ] ,clieIP[BUFSIZ]; struct sockaddr_in servaddr, clieaddr; socklen_t clieaddr_len; // 创建套接字 if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1 ) { perr_exit("socket error"); } // 绑定套接字地址 bzero(&servaddr, sizeof(servaddr)); servaddr.sin_family = AF_INET; servaddr.sin_port = htons(SERV_PORT); servaddr.sin_addr.s_addr = htonl(SERV_IP); if((n = bind(listenfd, (struct sockaddr *)&servaddr, sizeof(servaddr))) == -1) { perr_exit("bind error"); } // 监听 if ((n = listen(listenfd, MAXLISTENQ)) == -1) { perr_exit("listen error"); } printf("wait for client connect ...\n"); clieaddr_len = sizeof(clieaddr); if ((connfd = accept(listenfd, (struct sockaddr *)&clieaddr, &clieaddr_len)) == -1) { perr_exit("accept error"); } // 显示客户端的IP地址 if (inet_ntop(AF_INET, &clieaddr.sin_addr.s_addr, clieIP, sizeof(clieIP)) == NULL) { perr_exit("inet_ntop error"); } printf("connected---> client IP address: %s\tport: %d\t\n", clieIP, ntohs(clieaddr.sin_port)); while (1) { // 从客户端读取信息 if ((n = read(connfd, &buf, sizeof(buf))) == -1) { perr_exit("read error"); } // 打印到标准输出 write(STDOUT_FILENO, buf, n); for (int i = 0; i < n; i++) { buf[i] = toupper(buf[i]); } // 向客户端发送信息 if ((n = write(connfd, buf, n)) == -1) { perr_exit("write to client error"); } } return 0; }
一个简单的返回大写字母的服务器程序
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转载自blog.csdn.net/liang_gu/article/details/80596939
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