The multicast example from the NETOS4 manual doesn’t work in an proper way. especially the calls iTemp = 2; n = setsockopt(s, IPPROTO_IP, IP_MULTICAST_TTL, (char *) &iTemp, sizeof(iTemp)); and iTemp = 0; n = setsockopt(s, IPPROTO_IP, IP_MULTICAST_LOOP, (char *) &iTemp, sizeof(iTemp)); returns -1 (error code 22 - EINVAL). However, joining and leaving the multicast group works. Are these options not supported or is there a failure in my example?

There was a mistake on that, the example in the documentation uses an (int) tough it should be a ( char ) for iTmp which is used in the setsockopt for TTL. There is a running Multicast example api posted on the web under sample applications

Thanks, iTmp as char works fine. The multicast example on the web seems to use an int parameter like the documentation example.