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);
}

this style

Code:

initdevice(fd_flags, dflags)
int fd_flags;
u_long dflags;

is outdated
use

Code:

initdevice(int fd_flags,u_long dflags)

Code:

struct ifreq ifr;

your struct is not initialized - don't you get any warnings about -
ifr.ifr_flags |= IFF_PROMISC;
??
increase you warnings level (and maybe use more uptodate compiler)

No i am not getting any warnings, getting only this message

Cannot get interface flags: Invalid argument
can you tell me, where i did mistake interims of structure?
what is your opinion?

It is VERY impolite to ask the same question in multiple places:
http://www.linuxquestions.org/questi...gument-634527/

Vart: The struct should be initialized by the SIOCGIFFLAGS, but it appears that it doesn't do that (correctly).

I don't know what the answer to the actual question is - I searched in google for a while, but found only a vague link (that is 6 years old, so I don't know if there's any relevance NOW):
http://cygwin.com/ml/cygwin/2002-10/msg00884.html

It's probably worth filling in the ifr_addr field and see if that helps. Not quite sure how you get that info...

--
Mats