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多线程并发服务器

模型

sfd = socket();
bind();
listen();
while(1){newfd = accept();pthread_create(&tid, NULL, do_cli_msg, [newfd, cin]集合);pthread_detach(tid);
}
close(sfd);void* do_cli_msg(void* arg){while(1){recv();send();    }close(newfd);
}

服务器实现

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <pthread.h>#define PORT 8080
#define IP "192.168.124.38"
#define MAX_CLIENTS 5
#define BUFFER_SIZE 1024void *handle_client(void *arg);
int server_fd, new_socket, valread;
struct sockaddr_in address;
int opt = 1;
int addrlen = sizeof(address);
char buffer[BUFFER_SIZE] = {0};
fd_set readfds;int main() {// 创建socketif ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0) {perror("socket failed");exit(EXIT_FAILURE);}// 设置端口复用if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) {perror("setsockopt");exit(EXIT_FAILURE);}address.sin_family = AF_INET;                                                                                       address.sin_addr.s_addr = IP;address.sin_port = htons(PORT);// 绑定if (bind(server_fd, (struct sockaddr *)&address, sizeof(address))<0) {perror("bind failed");exit(EXIT_FAILURE);}// 监听if (listen(server_fd, MAX_CLIENTS) < 0) {perror("listen");exit(EXIT_FAILURE);}printf("服务器端口：%d...\n", PORT);while (1) {// 接受新的连接请求if ((new_socket = accept(server_fd, (struct sockaddr *)&address, (socklen_t*)&addrlen))<0) {perror("accept");exit(EXIT_FAILURE);}// 为新连接创建线程pthread_t client_thread;if(pthread_create(&client_thread, NULL, handle_client, (void*) &new_socket) < 0){perror("create thread");exit(EXIT_FAILURE);}// 分离线程，防止资源泄漏pthread_detach(client_thread);}return 0;
}void* handle_client(void* arg){int sock = *((int*)arg);char client_message[BUFFER_SIZE];while(1) {memset(client_message, 0, sizeof(client_message));valread = read(sock , client_message, BUFFER_SIZE);if(valread <= 0){// 发生错误或客户端关闭连接break;}printf("Client %d says: %s\n", sock, client_message);// 处理客户端消息并准备响应char *response = "服务器已就绪\n";send(sock , response , strlen(response) , 0 );}close(sock);printf("关闭socket： %d\n", sock);pthread_exit(NULL);}

---

select的TCP服务器

模型

sfd = socket();
bind();
listen();
while(1){tempfds = readfds;select(maxfd+1, &tempfds, NULL, NULL, NULL);for(int i=0; i<=maxfd; i++){if(FD_ISSET(i, &temfds) == 0)     continue;if(0 == i){                    }          else if(sfd == i){newfd=accept()FD_SET(newfd, &readfds);maxfd=newfd>maxfd?newfd:maxfd;        }   else{res=recv(i,  );if(0 == res){FD_CLR(i, &readfds);close(i);while(FD_ISSET(maxfd, &readfds)==0 && maxfd-->0);            }send(i,  );        }           }
}
close(sfd);

服务器实现

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/select.h>#define PORT 12345 int main() {int listenfd, newfd, maxfd, i, j, nbytes;struct sockaddr_in server_addr, client_addr;socklen_t addrlen;char buffer[1024];fd_set master_set, read_fds;if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {perror("socket");exit(1);}server_addr.sin_family = AF_INET;server_addr.sin_port = htons(PORT);server_addr.sin_addr.s_addr = 192.168.124.38;memset(&(server_addr.sin_zero), '\0', 8);if (bind(listenfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) {perror("bind");close(listenfd);exit(1);}if (listen(listenfd, 10 ) == -1) {perror("listen");close(listenfd);exit(1);}FD_ZERO(&master_set);FD_ZERO(&read_fds);FD_SET(listenfd, &master_set);maxfd = listenfd;while (1) {read_fds = master_set;if (select(maxfd + 1, &read_fds, NULL, NULL, NULL) == -1) {perror("select");exit(1);}for (i = 0; i <= maxfd; i++) {if (FD_ISSET(i, &read_fds)) {if (i == listenfd) {addrlen = sizeof(client_addr);if ((newfd = accept(listenfd, (struct sockaddr *)&client_addr, &addrlen)) == -1) {perror("accept");} else {FD_SET(newfd, &master_set);if (newfd > maxfd) {maxfd = newfd;}printf("New connection from %s on socket %d\n", inet_ntoa(client_addr.sin_addr), newfd);}} else {if ((nbytes = recv(i, buffer, sizeof(buffer), 0)) <= 0) {if (nbytes == 0) {printf("Socket %d hung up\n", i);} else {perror("recv");}close(i);FD_CLR(i, &master_set);} else {for (j = 0; j < nbytes; j += 0) {int sent = send(i, buffer + j, nbytes - j, 0);if (sent == -1) {perror("send");close(i);FD_CLR(i, &master_set);break;}j += sent;}}}}}}close(listenfd);return 0;
}

---

select的TCP客户端

实现

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/select.h>#define SERVER_IP "127.0.0.1"  // 服务器 IP 地址
#define SERVER_PORT 12345      // 服务器端口int main() {int sockfd, maxfd, nbytes;struct sockaddr_in server_addr;fd_set read_fds;char buffer[1024];if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1) {perror("socket");exit(1);}server_addr.sin_family = AF_INET;server_addr.sin_port = htons(SERVER_PORT);server_addr.sin_addr.s_addr = inet_addr(SERVER_IP);memset(&(server_addr.sin_zero), '\0', 8);if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(struct sockaddr)) == -1) {perror("connect");exit(1);}printf("Connected to server on socket %d\n", sockfd);while (1) {FD_ZERO(&read_fds);FD_SET(sockfd, &read_fds);FD_SET(STDIN_FILENO, &read_fds);maxfd = (sockfd > STDIN_FILENO ? sockfd : STDIN_FILENO) + 1;if (select(maxfd, &read_fds, NULL, NULL, NULL) == -1) {perror("select");exit(1);}if (FD_ISSET(STDIN_FILENO, &read_fds)) {if (fgets(buffer, sizeof(buffer), stdin) == NULL) {break;}nbytes = strlen(buffer);if (send(sockfd, buffer, nbytes, 0) == -1) {perror("send");exit(1);}}if (FD_ISSET(sockfd, &read_fds)) {if ((nbytes = recv(sockfd, buffer, sizeof(buffer), 0)) <= 0) {if (nbytes == 0) {printf("Server hung up\n");} else {perror("recv");}break;} else {printf("Received from server: %.*s", nbytes, buffer);}}}close(sockfd);return 0;
}