[MSDN Library April 2000] SIO_MULTICAST_SCOPE Command Code for WSAIoctl (50.6575963718821%)
MSDN Library - April 2000 > Platform SDK > Networking and Directory Services > Windows Sockets Version 2 > Windows Sockets Version 2 API > Overview > Multipoint and Multicast Semantics > Windows Sockets 2 Interface Elements for Multipoint and Multicast