programa corto en c++ buscar por nombre interfaces de red linux

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

#define MAX_LEN 1024

int main()
{
    struct ifconf ifc;
    struct ifreq  ifr[10];
    int x, fd;

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

    ifc.ifc_len = sizeof(ifr);
    ifc.ifc_buf = (char *)ifr;
    if (ioctl(fd, SIOCGIFCONF, &ifc) == -1) {
        perror("SI