c语言写一个x客户端

在C语言中，创建一个简单的telnet/xclient（X Window系统客户端）程序，通常用于与X服务器交互，可以使用`ncurses`库或者直接操作网络套接字。这里是一个基本的telnet客户端的例子，它使用`telnetlib`库：

#include <stdio.h>
#include <stdlib.h>
#include "telnetlib.h"

int main(int argc, char **argv) {
    struct addrinfo hints, *res;
    int sock = -1;
    struct sockaddr_in server_addr;

    if (argc != 2) {
        fprintf(stderr, "Usage: %s <hostname>\n", argv[0]);
        return 1;
    }

    // 获取主机信息
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC; // 不指定AF_INET还是AF_INET6
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

    if ((sock = socket(hints.ai_family, hints.ai_socktype, hints.ai_protocol)) == -1) {
        perror("Error creating socket");
        exit(1);
    }

    if (getaddrinfo(argv[1], "23", &hints, &res) != 0) { // telnet默认端口是23
        perror("Error resolving address");
        exit(1);
    }

    // 连接到服务器
    if (connect(sock, res->ai_addr, res->ai_addrlen) == -1) {
        perror("Error connecting to server");
        freeaddrinfo(res);
        exit(1);
    }

    // 发送命令并接收响应
    printf("Connecting to %s...\n", argv[1]);
    char cmd[] = "USER your_username\r\n"; // 用实际用户名替换your_username
    send(sock, cmd, strlen(cmd), 0);

    char buffer[1024] = "";
    ssize_t bytes_received;
    while ((bytes_received = recv(sock, buffer, sizeof(buffer), 0)) > 0) {
        buffer[bytes_received] = '\0'; // null-terminate the received data
        printf("Server response: %s\n", buffer);
    }

    // 关闭连接
    close(sock);
    freeaddrinfo(res);

    return 0;
}