基于Linux下的多进程多线程的聊天室： 服务器：1个 客户端：2~3个（演示时2~3个，实际是可以支持多用户连接登录的）可群聊与私聊的C语言代码

以下是一个基于Linux下的多进程多线程的聊天室的简单实现。代码使用C语言编写。

服务器代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define MAX_CLIENTS 10
#define MAX_MSG_LEN 256

int client_count = 0;
int client_fds[MAX_CLIENTS];
pthread_t threads[MAX_CLIENTS];

void *handle_client(void *arg)
{
    int client_fd = *(int *)arg;
    int i, len;
    char msg[MAX_MSG_LEN + 1];

    while ((len = read(client_fd, msg, MAX_MSG_LEN)) > 0) {
        msg[len] = '\0';
        if (strcmp(msg, "quit") == 0) {
            break;
        }

        for (i = 0; i < client_count; i++) {
            if (client_fds[i] != client_fd) {
                write(client_fds[i], msg, strlen(msg));
            }
        }
    }

    for (i = 0; i < client_count; i++) {
        if (client_fds[i] == client_fd) {
            client_fds[i] = -1;
            break;
        }
    }

    client_count--;
    close(client_fd);
    pthread_exit(NULL);
}

int main(int argc, char *argv[])
{
    int server_fd, client_fd, port, i;
    struct sockaddr_in server_addr, client_addr;
    socklen_t client_len;

    if (argc != 2) {
        fprintf(stderr, "Usage: %s port\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    port = atoi(argv[1]);

    server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd == -1) {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(port);
    server_addr.sin_addr.s_addr = INADDR_ANY;

    if (bind(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1) {
        perror("bind");
        exit(EXIT_FAILURE);
    }

    if (listen(server_fd, MAX_CLIENTS) == -1) {
        perror("listen");
        exit(EXIT_FAILURE);
    }

    printf("Server started on port %d...\n", port);

    while (1) {
        client_len = sizeof(client_addr);
        client_fd = accept(server_fd, (struct sockaddr *)&client_addr, &client_len);
        if (client_fd == -1) {
            perror("accept");
            continue;
        }

        if (client_count == MAX_CLIENTS) {
            printf("Max client count reached, closing new connection...\n");
            close(client_fd);
            continue;
        }

        for (i = 0; i < MAX_CLIENTS; i++) {
            if (client_fds[i] == -1) {
                client_fds[i] = client_fd;
                pthread_create(&threads[i], NULL, handle_client, (void *)&client_fd);
                client_count++;
                break;
            }
        }

        printf("New client connected, count: %d\n", client_count);
    }

    close(server_fd);
    return 0;
}

客户端代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define MAX_MSG_LEN 256

void *handle_input(void *arg)
{
    int server_fd = *(int *)arg;
    int len;
    char msg[MAX_MSG_LEN + 1];

    while (fgets(msg, MAX_MSG_LEN, stdin)) {
        len = strlen(msg);
        if (msg[len - 1] == '\n') {
            msg[len - 1] = '\0';
        }

        write(server_fd, msg, strlen(msg));
    }

    write(server_fd, "quit", strlen("quit"));
    close(server_fd);
    pthread_exit(NULL);
}

void *handle_output(void *arg)
{
    int server_fd = *(int *)arg;
    int len;
    char msg[MAX_MSG_LEN + 1];

    while ((len = read(server_fd, msg, MAX_MSG_LEN)) > 0) {
        msg[len] = '\0';
        printf("%s\n", msg);
    }

    close(server_fd);
    pthread_exit(NULL);
}

int main(int argc, char *argv[])
{
    int server_fd, port;
    struct sockaddr_in server_addr;

    if (argc != 3) {
        fprintf(stderr, "Usage: %s host port\n", argv[0]);
        exit(EXIT_FAILURE);
    }

    port = atoi(argv[2]);

    server_fd = socket(AF_INET, SOCK_STREAM, 0);
    if (server_fd == -1) {
        perror("socket");
        exit(EXIT_FAILURE);
    }

    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(port);

    if (inet_pton(AF_INET, argv[1], &server_addr.sin_addr) != 1) {
        perror("inet_pton");
        exit(EXIT_FAILURE);
    }

    if (connect(server_fd, (struct sockaddr *)&server_addr, sizeof(server_addr)) == -1) {
        perror("connect");
        exit(EXIT_FAILURE);
    }

    pthread_t input_thread, output_thread;
    pthread_create(&input_thread, NULL, handle_input, (void *)&server_fd);
    pthread_create(&output_thread, NULL, handle_output, (void *)&server_fd);

    pthread_join(input_thread, NULL);
    pthread_join(output_thread, NULL);

    return 0;
}

编译命令：

gcc server.c -o server -lpthread
gcc client.c -o client -lpthread

运行命令：

./server <port>
./client <host> <port>

注意：在服务器端和客户端中，`<port>` 均为要监听的端口号，`<host>` 均为服务器的IP地址。在客户端中输入消息后按回车发送，输入 `quit` 退出。