Thread: Cannot get interface flags: Invalid argument

hello,
I can not interface flag. Actually getting invalid argument. Can any one give me feedback. See my flag function....

Code:

/************************************************************************
Function:  initdevice

Description: Set up the network device so we can read it.

**************************************************************************/
initdevice(fd_flags, dflags)
int fd_flags;
u_long dflags;
{
    struct ifreq ifr;
    int fd, flags = 0;

    if((fd = socket(PF_INET, SOCK_PACKET, htons(0x0003))) < 0)
    {
	perror("Cannot open device socket");
	exit(-1);
    }

    /* Get the existing interface flags */

    strcpy(ifr.ifr_name, Gdevice);
    if(ioctl(fd, SIOCGIFFLAGS, &ifr) < 0)
    {
	perror("Cannot get interface flags");
	exit(-1);
    }

    ifr.ifr_flags |= IFF_PROMISC;
    if(ioctl(fd, SIOCSIFFLAGS,  &ifr) < 0)
    {
	perror("Cannot set interface flags");
	exit(-1);
    }
    
    return(fd);
}