#include <stdio.h>
#include <sys/types.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <unistd.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <errno.h>

int main(void) {
        static struct ifreq ifr;
        static char *ip;
        static char *ifname = "eth0";
        int sock;

        //create our sock
        sock = socket(AF_INET,SOCK_DGRAM,0);

        strcpy( ifr.ifr_name, ifname );
        ifr.ifr_addr.sa_family = AF_INET;

        // w00p get the iface addr ;>
        if (ioctl( sock, SIOCGIFADDR, &ifr ) < 0)
        perror("ioctl:");
        ip = inet_ntoa( ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr );
        printf("%s\n",ip);
        return 0;
}