Find Interface name

[chellappa]

hi all,
i trying to find the intferface name using this coding ,but that is
not working ,,,if anybody this pervious..pleas e help to find the
interface name using Linux C.

//CODE
ioctl(sd, SIOCGIFNAME, &ifr);
strncpy(ifname, ifr.ifr_name,IF NAMSIZ);
printf("Interfa ce name :%s\n",ifname);

//
thanks all

[Eric Sosman]

Re: Find Interface name

chellappa wrote:[color=blue]
> hi all,
> i trying to find the intferface name using this coding ,but that is
> not working ,,,if anybody this pervious..pleas e help to find the
> interface name using Linux C.
>
> //CODE
> ioctl(sd, SIOCGIFNAME, &ifr);
> strncpy(ifname, ifr.ifr_name,IF NAMSIZ);
> printf("Interfa ce name :%s\n",ifname);[/color]

In Standard C, an `int' is guaranteed to be able
to count as high as 32767. Some implementations use
a wider `int', but 32767 is the maximum you can be
absolutely sure of.

If one were to write a program to count the number
of times Chellappa has been told that Standard C has
no networking facilities, the number of times he has
been told to take his networking questions to newsgroups
where networking experts hang out, the number of times
he has been given the names of those newsgroups, and the
number of times he has utterly failed to get the message,
would it be wise to use a mere `int' for the counter?

--
Eric Sosman
esosman@acm-dot-org.invalid

[Joe Estock]

[OT] Re: Find Interface name

Eric Sosman wrote:[color=blue]
> chellappa wrote:
>[color=green]
>> hi all,
>> i trying to find the intferface name using this coding ,but that is
>> not working ,,,if anybody this pervious..pleas e help to find the
>> interface name using Linux C.
>>
>> //CODE
>> ioctl(sd, SIOCGIFNAME, &ifr);
>> strncpy(ifname, ifr.ifr_name,IF NAMSIZ);
>> printf("Interfa ce name :%s\n",ifname);[/color]
>
>
> In Standard C, an `int' is guaranteed to be able
> to count as high as 32767. Some implementations use
> a wider `int', but 32767 is the maximum you can be
> absolutely sure of.
>
> If one were to write a program to count the number
> of times Chellappa has been told that Standard C has
> no networking facilities, the number of times he has
> been told to take his networking questions to newsgroups
> where networking experts hang out, the number of times
> he has been given the names of those newsgroups, and the
> number of times he has utterly failed to get the message,
> would it be wise to use a mere `int' for the counter?
>[/color]

I'd put bets on at least an unsigned long, preferably an unsigned long
long if the implementation supports it.

Joe

[wcang79@gmail.com]

Re: Find Interface name

Hi,

I don't know about SIOCGIFNAME, but I assume that what you want is
to call ioctl(sd, SIOCGIFCONF, &ifconf) to obtain all the network
interfaces on your system.

Regards,
Ang Way Chuang

[wcang79@gmail.com]

Re: Find Interface name

In addition, you may also want to look into these 2 functions:

char *if_indextoname (unsigned ifindex, char *ifname);
struct if_nameindex *if_nameindex(v oid);

http://www.opengroup.org/onlinepubs/009695399/functions/if_indextoname.html

http://www.opengroup.org/onlinepubs/009695399/functions/if_nameindex.html

I think you should download Single Unix Specification version 3 from
www.opengroup.org if you plan to program in Unix. Hope this answer your
question.

Regards,
Ang Way Chuang