Programme multicast en C

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <netinet/in.h>

#include <stdio.h>

#include <stdlib.h>

 
 
struct in_addr localInterface;

struct sockaddr_in groupSock;

int sd;

int datalen;

char databuf[1024];

 
int main (int argc, char *argv[])

{

        sd = socket(AF_INET, SOCK_DGRAM, 0);

        if (sd < 0) {

        perror("opening datagram socket");

        exit(1);

                         }

 
memset((char *) &groupSock, 0, sizeof(groupSock));

groupSock.sin_family = AF_INET;

groupSock.sin_addr.s_addr = inet_addr("225.1.1.1");

groupSock.sin_port = htons(5555);

 
   {

     char loopch=0;

 
     if (setsockopt(sd, IPPROTO_IP, IP_MULTICAST_LOOP,

     (char *)&loopch, sizeof(loopch)) < 0) {

     perror("setting IP_MULTICAST_LOOP:");

     close(sd);

     exit(1);

   }

}

   localInterface.s_addr = inet_addr("9.5.1.1");

   if (setsockopt(sd, IPPROTO_IP, IP_MULTICAST_IF,

   (char *)&localInterface,

   sizeof(localInterface)) < 0)

     {

               perror("setting local interface");

               exit(1);

      }

datalen = 10;

if (sendto(sd, databuf, datalen, 0,

(struct sockaddr*)&groupSock,

sizeof(groupSock)) < 0)

     {

              perror("sending datagram message");

      }