#include    <errno.h>

#include    <net/if.h>

#include    <sys/socket.h>

#include    <netinet/in.h>

int sockfd_to_family(int);

int mcast_get_ttl(int sockfd)

{

    switch (sockfd_to_family(sockfd)) {

        case AF_INET: {

            u_char        ttl;

            socklen_t    len;

            len = sizeof(ttl);

            if (getsockopt(sockfd, IPPROTO_IP,

                IP_MULTICAST_TTL, &ttl, &len) < ) {

                return(-);

            }

            return (ttl);

        }

#ifdef    IPV6

        case AF_INET6: {

            int            hop;

            socklen_t    len;

            len = sizeof(hop);

            if (getsockopt(sockfd, IPPROTO_IPV6,

                IPV6_MULTICAST_HOPS, &hop, &len) < ) {

                return(-);

            }

            return (hop);

        }

#endif

        default: {

            errno = EAFNOSUPPORT;

            return(-);

        }

    }

}