[C] How to get device ip

Usage :
char eth16[16]={0};
GetDeviceIP(“eth16”, eth16)

static int GetDeviceIP(char* device, char* ipaddr)
{
    int sockfd;
    struct ifreq req;

    if((!device)||(!ipaddr))
    {
       return -1;
    }

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

    memset(&req,0,sizeof(req));
    strncpy(req.ifr_name, device, sizeof(req.ifr_name)-1);
    if (ioctl(sockfd, SIOCGIFADDR, &req) < 0)
    {
        close( sockfd );
        return -1;
    }

    strcpy(ipaddr,inet_ntoa(((struct sockaddr_in*)&(req.ifr_addr))->sin_addr));

    close( sockfd );
    return 0;
}