服务器端：server.c
#include <stdio.h> #include <stdlib.h> #include <errno.h> #include <string.h> #include <sys/types.h> #include <netinet/in.h> #include <sys/socket.h> #include <sys/wait.h> #include <unistd.h> #include <arpa/inet.h> #include <sys/time.h> #include <sys/types.h> #define MAXBUF 1024 int main(int argc, char **argv) { int sockfd, new_fd; socklen_t len; struct sockaddr_in my_addr, their_addr; unsigned int myport, lisnum; char buf[MAXBUF + 1]; fd_set rfds; struct timeval tv; int retval, maxfd = -1; if (argv[2]) myport = atoi(argv[2]); /* 将命令行字符串转换为整数。用于端口 */ else myport = 8888; /* 设置默认端口 */ if (argv[3]) lisnum = atoi(argv[3]); /* 监听队列大小 */ else lisnum = 2; if ((sockfd = socket(PF_INET, SOCK_STREAM, 0)) == -1) { /* 创建socket对象 */ perror("socket"); exit(EXIT_FAILURE); } bzero(&my_addr, sizeof(my_addr)); my_addr.sin_family = PF_INET; /* 地址协议 */ my_addr.sin_port = htons(myport); /* 地址端口 */ if (argv[1]) my_addr.sin_addr.s_addr = inet_addr(argv[1]); else my_addr.sin_addr.s_addr = INADDR_ANY; /* 否则默认本机随意地址 */ if (bind(sockfd, (struct sockaddr *) &my_addr, sizeof(struct sockaddr)) == -1) { /* 绑定地址信息 */ perror("bind"); exit(EXIT_FAILURE); } if (listen(sockfd, lisnum) == -1) { /* 监听网络 ，最大队列数是lisnum*/ perror("listen"); exit(EXIT_FAILURE); } while (1) { printf ("\n----wait for new connect\n"); len = sizeof(struct sockaddr);
if ((new_fd =accept(sockfd, (struct sockaddr *) &their_addr,&len)) == -1) {
/* 堵塞等待连接。连接成功返回新的socket描写叙述符，their_addr存储client的sockaddr 地址信息 perror("accept"); exit(errno); } else printf("server: got connection from %s, port %d, socket %d\n", inet_ntoa(their_addr.sin_addr),ntohs(their_addr.sin_port), new_fd); while (1) { FD_ZERO(&rfds); /* 清零rfds集合 */ FD_SET(0, &rfds); /* 把标准输入加入rfds集合 */ FD_SET(new_fd, &rfds); /* 把new_fd加入rfds集合 */ maxfd = new_fd; tv.tv_sec = 1; tv.tv_usec = 0; retval = select(maxfd + 1, &rfds, NULL, NULL, &tv); /* maxfd + 1监听的最大值加一 */ if (retval == -1) { perror("select");exit(EXIT_FAILURE);} else if (retval == 0) { continue; } else{ if (FD_ISSET(0, &rfds)) /* 假设是标准输入可读 */{ bzero(buf, MAXBUF + 1); fgets(buf, MAXBUF, stdin); if (!strncasecmp(buf, "quit", 4)) { printf("i will quit!\n"); break; } len = send(new_fd, buf, strlen(buf) - 1, 0); if (len > 0) printf ("send successful,%d byte send!\n",len); else { printf("send failure!"); break; }} if (FD_ISSET(new_fd, &rfds)) /* 假设是new_fd可读 */{ bzero(buf, MAXBUF + 1); len = recv(new_fd, buf, MAXBUF, 0); if (len > 0) printf ("recv success :'%s',%dbyte recv\n", buf, len); else{ if (len < 0) printf("recv failure\n"); else{ printf("the ohter one end ,quit\n"); break;} } } }} close(new_fd); printf("need othe connecdt (no->quit)"); fflush(stdout); bzero(buf, MAXBUF + 1); fgets(buf, MAXBUF, stdin); if (!strncasecmp(buf, "no", 2)) { printf("quit!\n"); break; } } close(sockfd); return 0; } 客户端程序：client.c
#include <stdio.h>
#include <string.h> #include <errno.h> #include <sys/socket.h> #include <resolv.h> #include <stdlib.h> #include <netinet/in.h> #include <arpa/inet.h> #include <unistd.h> #include <sys/time.h> #include <sys/types.h> #define MAXBUF 1024 int main(int argc, char **argv) { int sockfd, len; struct sockaddr_in dest; char buffer[MAXBUF + 1]; fd_set rfds; struct timeval tv; int retval, maxfd = -1; if (argc != 3) { printf("argv format errno,pls:\n\t\t%s IP port\n",argv[0], argv[0]); exit(EXIT_FAILURE); } if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) { perror("Socket"); exit(EXIT_FAILURE); } bzero(&dest, sizeof(dest)); dest.sin_family = AF_INET; dest.sin_port = htons(atoi(argv[2])); if (inet_aton(argv[1], (struct in_addr *) &dest.sin_addr.s_addr) == 0) { perror(argv[1]); exit(EXIT_FAILURE); } if (connect(sockfd, (struct sockaddr *) &dest, sizeof(dest)) != 0) { perror("Connect "); exit(EXIT_FAILURE); } printf("\nget ready pls chat\n"); while (1) { FD_ZERO(&rfds); FD_SET(0, &rfds); FD_SET(sockfd, &rfds); maxfd = sockfd; tv.tv_sec = 1; tv.tv_usec = 0; retval = select(maxfd + 1, &rfds, NULL, NULL, &tv); if (retval == -1) { printf("select %s", strerror(errno)); break; } else if (retval == 0) continue;else{ if (FD_ISSET(sockfd, &rfds)) { bzero(buffer, MAXBUF + 1); len = recv(sockfd, buffer, MAXBUF, 0); if (len > 0) printf ("recv message:'%s',%d byte recv\n",buffer, len); else { if (len < 0) printf ("message recv failure\n"); else{ printf("the othe quit ,quit\n"); break;} } } if (FD_ISSET(0, &rfds)) { bzero(buffer, MAXBUF + 1); fgets(buffer, MAXBUF, stdin); if (!strncasecmp(buffer, "quit", 4)) { printf("i will quit\n"); break; } len = send(sockfd, buffer, strlen(buffer) - 1, 0); if (len < 0) { printf ("message send failure"); break; } else printf ("send success,%d byte send\n",len); } } } close(sockfd); return 0; }
測试方法例如以下：
gcc server.c -o server
gcc client.c -o client
./server 172.16.148.114 8888 /* 一个终端下。172.16.148.114是我虚拟机的IP地址*/
./client 172.16.148.114 8888 /*另外 一个终端下 */
select函数不会使用的參考这篇文章：