Multicast UDP in VS6 C or C++

[emp]

Plenty of examples on line for later versions of Visual Studio.

I have the MSDN for VS6.0

There is no mention of Multicast UDP sockets. There is Broadcast. Looking at the socket options I find SO_BROADCAST. There is no corresponding MULTICAST socket option. Does anyone know if it even exists or am I chasing a Holy Grail????

Thanks

-E

[weaknessforcats]

https://msdn.microsoft.com/en-us/library/windows/desktop/ms739173(v=vs.85).aspx

[emp]

I had found that link last week and it created more questions. The struct ip_mreq_source is not defined anywhere in my VS6 environment. I found a definition of the struct on line and I implemented it in an existing header file. Next IP_ADD_SOURCE_M EMBERSHIP and IP_DROP_SOURCE_ MEMBERSHIP were undefined anywhere in the VS6 environment. I found them online and defined them with a #define. The variables grpaddr, srcaddr, iaddr are left to the imagination.
and Lastly do the standard sendto() and recvfrom() functions just plug in here. I've got this partially implemented to see if it will work for me.