c++基于socket的多线程聊天程序

基于socket的多线程聊天程序可以使用C++语言实现。下面是一个简单的示例：

1. 客户端代码

#include <iostream>
#include <unistd.h>
#include <cstring>
#include <cstdlib>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <pthread.h>

#define MAX_MSG_SIZE 1024
#define SERVER_PORT 8080
#define SERVER_IP "127.0.0.1"

void *receive_message(void *arg) {
    int sockfd = *(int *) arg;
    char message[MAX_MSG_SIZE];
    while (true) {
        memset(message, 0, MAX_MSG_SIZE);
        int len = recv(sockfd, message, MAX_MSG_SIZE, 0);
        if (len > 0) {
            std::cout << message << std::endl;
        } else if (len == 0) {
            std::cout << "Server disconnected." << std::endl;
            break;
        } else {
            std::cerr << "Error receiving message from server." << std::endl;
            break;
        }
    }
    close(sockfd);
    exit(0);
}

int main() {
    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        std::cerr << "Error creating socket." << std::endl;
        exit(1);
    }

    struct sockaddr_in server_addr;
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(SERVER_PORT);
    inet_pton(AF_INET, SERVER_IP, &server_addr.sin_addr);

    if (connect(sockfd, (struct sockaddr *) &server_addr, sizeof(server_addr)) < 0) {
        std::cerr << "Error connecting to server." << std::endl;
        exit(1);
    }

    std::cout << "Connected to server." << std::endl;

    pthread_t thread;
    if (pthread_create(&thread, NULL, receive_message, &sockfd) != 0) {
        std::cerr << "Error creating thread." << std::endl;
        exit(1);
    }

    std::string message;
    while (true) {
        std::getline(std::cin, message);
        if (message == "exit") {
            break;
        }
        send(sockfd, message.c_str(), message.size(), 0);
    }

    close(sockfd);
    return 0;
}

2. 服务器端代码

#include <iostream>
#include <cstring>
#include <cstdlib>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>
#include <pthread.h>

#define MAX_MSG_SIZE 1024
#define SERVER_PORT 8080

struct client_info {
    int sockfd;
    struct sockaddr_in addr;
};

void *handle_client(void *arg) {
    struct client_info *client = (struct client_info *) arg;
    char message[MAX_MSG_SIZE];
    while (true) {
        memset(message, 0, MAX_MSG_SIZE);
        int len = recv(client->sockfd, message, MAX_MSG_SIZE, 0);
        if (len > 0) {
            std::cout << inet_ntoa(client->addr.sin_addr) << ":" << ntohs(client->addr.sin_port) << " - "
                      << message << std::endl;
        } else if (len == 0) {
            std::cout << inet_ntoa(client->addr.sin_addr) << ":" << ntohs(client->addr.sin_port)
                      << " disconnected." << std::endl;
            break;
        } else {
            std::cerr << "Error receiving message from client." << std::endl;
            break;
        }
    }
    close(client->sockfd);
    delete client;
    return NULL;
}

int main() {
    int server_sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_sockfd < 0) {
        std::cerr << "Error creating socket." << std::endl;
        exit(1);
    }

    struct sockaddr_in server_addr;
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(SERVER_PORT);
    server_addr.sin_addr.s_addr = htonl(INADDR_ANY);

    if (bind(server_sockfd, (struct sockaddr *) &server_addr, sizeof(server_addr)) < 0) {
        std::cerr << "Error binding socket." << std::endl;
        exit(1);
    }

    if (listen(server_sockfd, 10) < 0) {
        std::cerr << "Error listening on socket." << std::endl;
        exit(1);
    }

    std::cout << "Server started. Listening on port " << SERVER_PORT << std::endl;

    while (true) {
        struct sockaddr_in client_addr;
        socklen_t addr_len = sizeof(client_addr);
        int client_sockfd = accept(server_sockfd, (struct sockaddr *) &client_addr, &addr_len);
        if (client_sockfd < 0) {
            std::cerr << "Error accepting connection." << std::endl;
            continue;
        }

        std::cout << inet_ntoa(client_addr.sin_addr) << ":" << ntohs(client_addr.sin_port)
                  << " connected." << std::endl;

        struct client_info *client = new client_info();
        client->sockfd = client_sockfd;
        client->addr = client_addr;

        pthread_t thread;
        if (pthread_create(&thread, NULL, handle_client, client) != 0) {
            std::cerr << "Error creating thread." << std::endl;
            break;
        }
    }

    close(server_sockfd);
    return 0;
}

该示例实现了一个简单的基于socket的多线程聊天程序，可以让客户端和服务器之间相互发送消息。在该示例中，客户端和服务器使用TCP/IP协议进行通信，客户端连接到服务器后，将通过一个线程持续接收服务器发送的消息，而主线程则负责发送消息给服务器。服务器会在接收到客户端的连接请求后，为该连接创建一个新的线程，并持续接收该客户端发送的消息。