On Mon, Feb 19, 2001 at 04:40:02PM +0530, vrd_boss@indya.com wrote:
> Hello,
> I don't know how to join to a multicast
> group in Linux.
> My ethernet card is multicast enabled.
> (from the ifconfig)
> Could You tell me how to join to a
> multicast group.
> Please help me.
Do you have some specific multicast group in mind? All the applications
that utilize multicast can do it by themselves already, it's only a few
lines of code.
Or do you want to join a multicast group in your own program? If so, here
the few lines of code I mentioned. It's totally untested, lacks all error
checking and such, but should give you the idea.
struct ip_mreq imr;
int sock;
sock = socket(AF_INET, SOCK_DGRAM, 0);
memset(&imr, 0, sizeof(imr));
inet_aton("224.0.0.1", &imr.imr_multiaddr);
setsockopt(sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, &imr, sizeof(imr));
However, if your upstream router does not support multicast routing,
joining a multicast group won't do you much good since you will be limited
to the multicast traffic within your own LAN.
--
Tommi Komulainen Tommi.Komulainen@iki.fi
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