linux下c 获取本机ip

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

int get_local_ip(char *ip) {
    int sockfd;
    struct sockaddr_in sin;
    struct ifreq ifr;

    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if (sockfd == -1) {
        perror("socket");
        return -1;
    }

    strncpy(ifr.ifr_name, "eth0", IFNAMSIZ); // 使用eth0接口，根据实际情况修改
    ifr.ifr_name[IFNAMSIZ - 1] = '\0';

    if (ioctl(sockfd, SIOCGIFADDR, &ifr) == 0) {
        memcpy(&sin, &ifr.ifr_addr, sizeof(sin));
        strcpy(ip, inet_ntoa(sin.sin_addr));
    } else {
        perror("ioctl");
        close(sockfd);
        return -1;
    }

    close(sockfd);
    return 0;
}

int main() {
    char ip[16];
    if (get_local_ip(ip) == 0) {
        printf("Local IP: %s\n", ip);
    } else {
        printf("Failed to get local IP.\n");
    }
    return 0;
}