Listing 2 Multicast sender: msend.c

#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>

main(int argc, char *argv[])
{
    struct sockaddr_in addr;
    int i, fd, ttl=64;

    fd=socket(AF_INET,SOCK_DGRAM,0);
    setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, 
      (char *) &ttl, 1);

    memset(&addr,0,sizeof(addr));
    addr.sin_family=AF_INET;
    addr.sin_addr.s_addr =inet_addr("225.10.10.1");
    addr.sin_port=htons(12345);

    sendto(fd, argv[1], strlen(argv[1]), 0, 
        (struct sockaddr *) &addr, sizeof(addr));

    close(fd);
}