摘抄自
https://blog.csdn.net/lovekun1989/article/details/41042273
https://blog.csdn.net/Ctrl_qun/article/details/52524086
分为无select和有select版本,无select只能一个服务端一个客户端,有select能一个服务端对应多个客户端。
无select,服务端代码
/*socket tcp服务器端*/
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>#define SERVER_PORT 5555/*监听后,一直处于accept阻塞状态,直到有客户端连接,当客户端如数quit后,断开与客户端的连接*/int main()
{//调用socket函数返回的文件描述符int serverSocket;//声明两个套接字sockaddr_in结构体变量,分别表示客户端和服务器struct sockaddr_in server_addr;struct sockaddr_in clientAddr;int addr_len = sizeof(clientAddr);int client;char buffer[200];int iDataNum;//socket函数,失败返回-1//int socket(int domain, int type, int protocol);//第一个参数表示使用的地址类型,一般都是ipv4,AF_INET//第二个参数表示套接字类型:tcp:面向连接的稳定数据传输SOCK_STREAM//第三个参数设置为0if((serverSocket = socket(AF_INET, SOCK_STREAM, 0)) < 0){perror("socket");return 1;}bzero(&server_addr, sizeof(server_addr));//初始化服务器端的套接字,并用htons和htonl将端口和地址转成网络字节序server_addr.sin_family = AF_INET;server_addr.sin_port = htons(SERVER_PORT);//ip可是是本服务器的ip,也可以用宏INADDR_ANY代替,代表0.0.0.0,表明所有地址server_addr.sin_addr.s_addr = htonl(INADDR_ANY);//对于bind,accept之类的函数,里面套接字参数都是需要强制转换成(struct sockaddr *)//bind三个参数:服务器端的套接字的文件描述符,if(bind(serverSocket, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0){perror("connect");return 1;}//设置服务器上的socket为监听状态if(listen(serverSocket, 5) < 0) {perror("listen");return 1;}while(1){printf("Listening on port: %d\n", SERVER_PORT);//调用accept函数后,会进入阻塞状态//accept返回一个套接字的文件描述符,这样服务器端便有两个套接字的文件描述符,//serverSocket和client。//serverSocket仍然继续在监听状态,client则负责接收和发送数据//clientAddr是一个传出参数,accept返回时,传出客户端的地址和端口号//addr_len是一个传入-传出参数,传入的是调用者提供的缓冲区的clientAddr的长度,以避免缓冲区溢出。//传出的是客户端地址结构体的实际长度。//出错返回-1client = accept(serverSocket, (struct sockaddr*)&clientAddr, (socklen_t*)&addr_len);if(client < 0){perror("accept");continue;}printf("\nrecv client data...n");//inet_ntoa ip地址转换函数,将网络字节序IP转换为点分十进制IP//表达式:char *inet_ntoa (struct in_addr);printf("IP is %s\n", inet_ntoa(clientAddr.sin_addr));printf("Port is %d\n", htons(clientAddr.sin_port));while(1){iDataNum = recv(client, buffer, 1024, 0);if(iDataNum < 0){perror("recv");continue;}buffer[iDataNum] = '\0';if(strcmp(buffer, "quit") == 0)break;printf("%drecv data is %s\n", iDataNum, buffer);send(client, buffer, iDataNum, 0);}}return 0;
}
无select,客户端代码
/*socket tcp客户端*/
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>#define SERVER_PORT 5555/*连接到服务器后,会不停循环,等待输入,输入quit后,断开与服务器的连接*/int main()
{//客户端只需要一个套接字文件描述符,用于和服务器通信int clientSocket;//描述服务器的socketstruct sockaddr_in serverAddr;char sendbuf[200];char recvbuf[200];int iDataNum;if((clientSocket = socket(AF_INET, SOCK_STREAM, 0)) < 0){perror("socket");return 1;}serverAddr.sin_family = AF_INET;serverAddr.sin_port = htons(SERVER_PORT);//指定服务器端的ip,本地测试:127.0.0.1//inet_addr()函数,将点分十进制IP转换成网络字节序IPserverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");if(connect(clientSocket, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) < 0){perror("connect");return 1;}printf("connect with destination host...\n");while(1){printf("Input your world:>");scanf("%s", sendbuf);printf("\n");send(clientSocket, sendbuf, strlen(sendbuf), 0);if(strcmp(sendbuf, "quit") == 0)break;iDataNum = recv(clientSocket, recvbuf, 200, 0);recvbuf[iDataNum] = '\0';printf("recv data of my world is: %s\n", recvbuf);}close(clientSocket);return 0;
}
有select,服务端代码
/*socket tcp服务器端*/
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>#define SERVER_PORT 5555
#define CLIENT_MAX 5
#define BUFFER_SIZE 200int main()
{int serverSocket;struct sockaddr_in server_addr;struct sockaddr_in clientAddr;int addr_len = sizeof(clientAddr);int client, i, ret;char buffer[BUFFER_SIZE];char in_msg[BUFFER_SIZE];char recv_msg[BUFFER_SIZE];int iDataNum;int client_fds[CLIENT_MAX];fd_set server_fd_set;int max_fd = -1;struct timeval tv;if((serverSocket = socket(AF_INET, SOCK_STREAM, 0)) < 0){perror("socket");return 1;}bzero(&server_addr, sizeof(server_addr));//初始化服务器端的套接字,并用htons和htonl将端口和地址转成网络字节序server_addr.sin_family = AF_INET;server_addr.sin_port = htons(SERVER_PORT);//ip可是是本服务器的ip,也可以用宏INADDR_ANY代替,代表0.0.0.0,表明所有地址server_addr.sin_addr.s_addr = htonl(INADDR_ANY);//对于bind,accept之类的函数,里面套接字参数都是需要强制转换成(struct sockaddr *)//bind三个参数:服务器端的套接字的文件描述符,if(bind(serverSocket, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {perror("connect");return 1;}if(listen(serverSocket, 5) < 0) {perror("listen");return 1;}while(1) {tv.tv_sec = 20;tv.tv_usec = 0;FD_ZERO(&server_fd_set);FD_SET(STDIN_FILENO, &server_fd_set);if (max_fd < STDIN_FILENO) {max_fd = STDIN_FILENO;}FD_SET(serverSocket, &server_fd_set);if (max_fd < serverSocket) {max_fd = serverSocket;}for (i = 0; i < CLIENT_MAX; i++) {if (client_fds[i] != 0) {FD_SET(client_fds[i], &server_fd_set);if (max_fd < client_fds[i]) {max_fd = client_fds[i];}}}ret = select(max_fd + 1, &server_fd_set, NULL, NULL, &tv);if (ret < 0) {perror("select error");continue;} else if (ret == 0) {printf("wait ...\n");continue;} else {if (FD_ISSET(STDIN_FILENO, &server_fd_set)) {printf("send msg:");memset(in_msg, 0, BUFFER_SIZE);fgets(in_msg, BUFFER_SIZE, stdin);if (strcmp(in_msg, "quit") == 0) {exit(0);}for (i = 0; i < CLIENT_MAX; i++) {if (client_fds[i] != 0) {printf("send msg to [i:%d] [fd:%d]..\n", i, client_fds[i]);send(client_fds[i], in_msg, BUFFER_SIZE, 0);}}}if (FD_ISSET(serverSocket, &server_fd_set)) {client = accept(serverSocket, (struct sockaddr*)&clientAddr, (socklen_t*)&addr_len);if(client > 0) {int index =-1;for (i = 0; i < CLIENT_MAX; i++) {if (client_fds[i] == 0) {client_fds[i] = client;index = i;break;}}if (index >= 0) {printf("add client [%d] success, %s:%d.\n", index, inet_ntoa(clientAddr.sin_addr),htons(clientAddr.sin_port));} else {memset(in_msg, 0, BUFFER_SIZE);strcpy(in_msg, "add client fail, reach max client.\n");send(client, in_msg, BUFFER_SIZE, 0);printf("add client fail, reach max client.\n");}}}for (i = 0; i < CLIENT_MAX; i++) {if (client_fds[i] !=0 ) {if (FD_ISSET(client_fds[i], &server_fd_set)) {memset(recv_msg, 0, BUFFER_SIZE);iDataNum = recv(client_fds[i], recv_msg, BUFFER_SIZE, 0);if (iDataNum < 0) {perror("recv");continue;} else if (iDataNum > 0) {if (iDataNum > BUFFER_SIZE) {iDataNum = BUFFER_SIZE;}recv_msg[iDataNum] = '\0';printf("recv %d msg:%s.\n", client_fds[i], recv_msg);} else {FD_CLR(client_fds[i], &server_fd_set);client_fds[i] = 0; printf("client (%d) exit.\n", i);}}}}}}return 0;
}
有select,客户端代码
/*socket tcp客户端*/
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>#define SERVER_PORT 5555/*连接到服务器后,会不停循环,等待输入,输入quit后,断开与服务器的连接*/int main()
{//客户端只需要一个套接字文件描述符,用于和服务器通信int clientSocket;//描述服务器的socketstruct sockaddr_in serverAddr;char sendbuf[200];char recvbuf[200];int iDataNum;fd_set client_fd_set;struct timeval tv;int ret;if((clientSocket = socket(AF_INET, SOCK_STREAM, 0)) < 0){perror("socket");return 1;}serverAddr.sin_family = AF_INET;serverAddr.sin_port = htons(SERVER_PORT);//指定服务器端的ip,本地测试:127.0.0.1//inet_addr()函数,将点分十进制IP转换成网络字节序IPserverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");if(connect(clientSocket, (struct sockaddr *)&serverAddr, sizeof(serverAddr)) < 0){perror("connect");return 1;}printf("connect with destination host...\n");while(1){tv.tv_sec = 20;tv.tv_usec = 0;FD_ZERO(&client_fd_set); FD_SET(STDIN_FILENO, &client_fd_set);FD_SET(clientSocket, &client_fd_set);ret = select(clientSocket + 1, &client_fd_set, NULL, NULL, &tv);if (ret < 0) {perror("select error");continue;} else if (ret == 0) {//超时continue;} if(FD_ISSET(STDIN_FILENO, &client_fd_set)) {memset(sendbuf, 0, 200);scanf("%s", sendbuf);send(clientSocket, sendbuf, strlen(sendbuf), 0);printf("send msg: %s\n");if(strcmp(sendbuf, "quit") == 0) {break;}}if(FD_ISSET(clientSocket, &client_fd_set)) {memset(recvbuf, 0, 200);iDataNum = recv(clientSocket, recvbuf, 200, 0);if (iDataNum > 0) {recvbuf[iDataNum] = '\0';printf("recv data of my world is: %s", recvbuf);} else if(iDataNum < 0) {printf("接受消息出错!\n");} else {printf("服务器端退出!\n");exit(0); }}}close(clientSocket);return 0;
}