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《TCP多线程通信代码C语言开发流程解析》

news 2025/8/24 9:56:14

TCP多线程通信代码开发流程解析——让步骤清晰明了

在编写 TCP 通信代码时，我经常中途忘记需要实现哪些步骤。为了更好地熟悉整个流程，并提高今后的开发效率，我打算自己写一篇文章，系统地整理并总结编写 TCP 通信所需的关键代码和步骤。

`服务端的流程`

服务端通过主线程接受客户端连接，并为每个连接创建独立会话线程(管理线程)，在会话线程中再启两个子线程分别负责读和写。

1.接收客户端并为其分配线程

创建sockaddr_in结构体及socket套接字

struct sockaddr_in server_addr;
memset(&server_addr,0,sizeof(server_addr));
server_addr.sin_addr.s_addr=htonl(INADDR_ANY);
server_addr.sin_family=AF_INET;
server_addr.sin_port=htons(port);
int len_server_addr=sizeof(server_addr);//结构体的大小
//套接字
int serverfd=socket(AF_INET,SOCK_STREAM,0);

bind绑定


temp_result=bind(serverfd,(struct sockaddr*)&server_addr,len_server_addr);if(temp_result){handle_error("bind",temp_result);}

listen监听

temp_result=listen(serverfd,10);//第二个参数是最多可以接受多少个客户端连接请求if(temp_result){handle_error("listen",temp_result);}

创建线程accept连接

关键点

pthread_t fd; 只是个变量。
每次调用 pthread_create，都会把新建线程的 ID 写到 fd 里。
你紧接着又 pthread_detach(fd)，把这个线程设置为**“分离态”**，这样它结束时系统能自动回收资源。
下一次循环时，pthread_create 会再次把新的线程 ID 写进 fd（覆盖掉旧的）。

pthread_t fd;
struct sockaddr_in client_addr;
memset(&client_addr,0,sizeof(client_addr));
int client_addr_len=sizeof(client_addr);
while (1)
{int *client_fd=malloc(sizeof(int));*client_fd=accept(serverfd,(struct sockaddr*)&client_addr,&client_addr_len);printf("客户端%d,ip:%s,已成功与服务端连接\n",*client_fd,inet_ntoa(client_addr.sin_addr));pthread_create(&fd,NULL,&raw,client_fd);pthread_detach(fd);
}
//释放资源
close(serverfd);

2.管理该客户端的读写子线程

为什么要传输文件描述符，这就相当于一个通道，没有他我们就找不到目标地址，也就无法进行读写操作，这就相当于一个通讯大门

void *read_func(void *arg)
{int server_fd = *(int *)arg;char *read_buf = malloc(1024);int temp_result;while (1){temp_result = recv(server_fd, read_buf, 1024, 0);if (temp_result == -1){perror("recv");}else if (temp_result == 0){printf("客户端关闭了连接\n");break;}read_buf[temp_result] = '\0'; // 安全添加结束符，防止乱码printf("客户端：%s\n", read_buf);}free(read_buf);return NULL;
}void *write_func(void *arg)
{int server_fd = *(int *)arg;char *write_buf = malloc(1024);int temp_result;while (1){memset(write_buf, 0, 1024);if (fgets(write_buf, 1024, stdin) == NULL){printf("输入有误\n");break;}if (strncmp(write_buf, "exit", 4) == 0){printf("服务端主动退出\n");break;}temp_result = send(server_fd, write_buf, strlen(write_buf), 0);if (temp_result == -1){perror("send");}else if (temp_result == 0){printf("服务器关闭了连接\n");break;}else{printf("服务端：%s\n", write_buf);}}free(write_buf);return NULL;
}void *raw(void * argv)
{int sockfd=*(int*)argv;pthread_t read_t,write_t;//创建子线程读取数据并打印到终端pthread_create(&read_t, NULL, read_func, argv);//创建子线程写入数据传到服务端pthread_create(&write_t, NULL, write_func, argv);// 主线程等待子线程退出pthread_join(read_t, NULL);pthread_join(write_t, NULL);free(argv);printf("关闭资源\n");close(sockfd);
}

3.完整代码展示

#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <pthread.h>
#include <string.h>#define port 6666#define handle_error(cmd, result) \if (result < 0)               \{                             \perror(cmd);              \return -1;                \}void *read_func(void *arg)
{int server_fd = *(int *)arg;char *read_buf = malloc(1024);int temp_result;while (1){temp_result = recv(server_fd, read_buf, 1024, 0);if (temp_result == -1){perror("recv");}else if (temp_result == 0){printf("客户端关闭了连接\n");break;}read_buf[temp_result] = '\0'; // 安全添加结束符，防止乱码printf("客户端：%s\n", read_buf);}free(read_buf);return NULL;
}void *write_func(void *arg)
{int server_fd = *(int *)arg;char *write_buf = malloc(1024);int temp_result;while (1){memset(write_buf, 0, 1024);if (fgets(write_buf, 1024, stdin) == NULL){printf("输入有误\n");break;}if (strncmp(write_buf, "exit", 4) == 0){printf("服务端主动退出\n");break;}temp_result = send(server_fd, write_buf, strlen(write_buf), 0);if (temp_result == -1){perror("send");}else if (temp_result == 0){printf("服务器关闭了连接\n");break;}else{printf("服务端：%s\n", write_buf);}}free(write_buf);return NULL;
}void *raw(void * argv)
{int sockfd=*(int*)argv;pthread_t read_t,write_t;//创建子线程读取数据并打印到终端pthread_create(&read_t, NULL, read_func, argv);//创建子线程写入数据传到服务端pthread_create(&write_t, NULL, write_func, argv);// 主线程等待子线程退出pthread_join(read_t, NULL);pthread_join(write_t, NULL);free(argv);printf("关闭资源\n");close(sockfd);
}int main(int argc, char const *argv[])
{int temp_result;//声明server结构体以及初始化struct sockaddr_in server_addr;memset(&server_addr,0,sizeof(server_addr));server_addr.sin_addr.s_addr=htonl(INADDR_ANY);server_addr.sin_family=AF_INET;server_addr.sin_port=htons(port);int len_server_addr=sizeof(server_addr);//套接字int serverfd=socket(AF_INET,SOCK_STREAM,0);//绑定temp_result=bind(serverfd,(struct sockaddr*)&server_addr,len_server_addr);if(temp_result){handle_error("bind",temp_result);}//监听temp_result=listen(serverfd,10);if(temp_result){handle_error("listen",temp_result);}//接收pthread_t fd;struct sockaddr_in client_addr;memset(&client_addr,0,sizeof(client_addr));int client_addr_len=sizeof(client_addr);while (1){int *client_fd=malloc(sizeof(int));*client_fd=accept(serverfd,(struct sockaddr*)&client_addr,&client_addr_len);printf("客户端%d,ip:%s,已成功与服务端连接\n",*client_fd,inet_ntoa(client_addr.sin_addr));pthread_create(&fd,NULL,&raw,client_fd);pthread_detach(fd);}//释放资源close(serverfd);return 0;
}

`客户端的流程`

创建sockaddr_in初始化
connect连接

1.连接服务端

int main(int argc, char const *argv[])
{// 套接字int client_fd = socket(AF_INET, SOCK_STREAM, 0);// 初始化struct sockaddr_in client_addr;memset(&client_addr, 0, sizeof(client_addr));client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");client_addr.sin_family = AF_INET;client_addr.sin_port = htons(6666);int client_addr_len = sizeof(client_addr);int sockfd = connect(client_fd, (struct sockaddr *)&client_addr, client_addr_len);if (sockfd == -1){handle_error("connect", sockfd);}pthread_t read_t, write_t;// 创建子线程读取数据并打印到终端pthread_create(&read_t, NULL, &read_func, (void *)&client_fd);// 创建子线程写入数据传到服务端pthread_create(&write_t, NULL, &write_func, (void *)&client_fd);// 主线程等待子线程退出pthread_join(read_t, NULL);pthread_join(write_t, NULL);printf("关闭资源\n");close(sockfd);return 0;
}

2.客户端的读写子线程

和服务端实现方法一样

void *read_func(void *arg)
{int server_fd = *(int *)arg;char *read_buf = malloc(1024);int temp_result;while (1){temp_result = recv(server_fd, read_buf, 1024, 0);if (temp_result == -1){perror("recv");}else if (temp_result == 0){printf("服务器关闭了连接\n");break;}read_buf[temp_result] = '\0'; // 安全添加结束符，防止乱码printf("服务器：%s\n", read_buf);}free(read_buf);return NULL;
}void *write_func(void *arg)
{int server_fd = *(int *)arg;char *write_buf = malloc(1024);int temp_result;while (1){memset(write_buf, 0, 1024);if (fgets(write_buf, 1024, stdin) == NULL){printf("输入有误\n");break;}if (strncmp(write_buf, "exit", 4) == 0){printf("客户端主动退出\n");break;}temp_result = send(server_fd, write_buf, strlen(write_buf), 0);if (temp_result == -1){perror("send");}else if (temp_result == 0){printf("服务器关闭了连接\n");break;}else{printf("客户端：%s\n", write_buf);}}free(write_buf);return NULL;
}

3.完整代码

#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <pthread.h>#define handle_error(cmd, result) \if (result < 0)               \{                             \perror(cmd);              \return -1;                \}void *read_func(void *arg)
{int server_fd = *(int *)arg;char *read_buf = malloc(1024);int temp_result;while (1){temp_result = recv(server_fd, read_buf, 1024, 0);if (temp_result == -1){perror("recv");}else if (temp_result == 0){printf("服务器关闭了连接\n");break;}read_buf[temp_result] = '\0'; // 安全添加结束符，防止乱码printf("服务器：%s\n", read_buf);}free(read_buf);return NULL;
}void *write_func(void *arg)
{int server_fd = *(int *)arg;char *write_buf = malloc(1024);int temp_result;while (1){memset(write_buf, 0, 1024);if (fgets(write_buf, 1024, stdin) == NULL){printf("输入有误\n");break;}if (strncmp(write_buf, "exit", 4) == 0){printf("客户端主动退出\n");break;}temp_result = send(server_fd, write_buf, strlen(write_buf), 0);if (temp_result == -1){perror("send");}else if (temp_result == 0){printf("服务器关闭了连接\n");break;}else{printf("客户端：%s\n", write_buf);}}free(write_buf);return NULL;
}int main(int argc, char const *argv[])
{// 套接字int client_fd = socket(AF_INET, SOCK_STREAM, 0);// 初始化struct sockaddr_in client_addr;memset(&client_addr, 0, sizeof(client_addr));client_addr.sin_addr.s_addr = inet_addr("127.0.0.1");client_addr.sin_family = AF_INET;client_addr.sin_port = htons(6666);int client_addr_len = sizeof(client_addr);int sockfd = connect(client_fd, (struct sockaddr *)&client_addr, client_addr_len);if (sockfd == -1){handle_error("connect", sockfd);}pthread_t read_t, write_t;// 创建子线程读取数据并打印到终端pthread_create(&read_t, NULL, &read_func, (void *)&client_fd);// 创建子线程写入数据传到服务端pthread_create(&write_t, NULL, &write_func, (void *)&client_fd);// 主线程等待子线程退出pthread_join(read_t, NULL);pthread_join(write_t, NULL);printf("关闭资源\n");close(sockfd);return 0;
}