socket_mcjoin4.c

It support IPv4 and IPv6 unicast and multicast and contains a trivial sender and a trivial receiver

#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include "socket.h"
#include "byte.h"

int socket_mcjoin4(int s,const char ip[4],const char interface[4])
{
  struct ip_mreq opt;
  byte_copy(&opt.imr_multiaddr.s_addr,4,ip);
  byte_copy(&opt.imr_interface.s_addr,4,interface);
  return setsockopt(s,IPPROTO_IP,IP_ADD_MEMBERSHIP,&opt,sizeof opt);
}