Im trying the GameDev Multicasting tutorial and Im getting a error with setsockopt(). Its throwing a WSAENOPROTOOPT defined by msdn as "The option is unknown or unsupported for the specified provider or socket." I have used the code that was used in the tutorial and its giving me that error. Does anyone have any idea why it doesnt like the option "IPPROTO_IP, IP_ADD_MEMBERSHIP"? Here is my code for the socket: int WSAProcess; int MyUDPSocket; WSAData WsaData; if((WSAProcess = WSAStartup(MAKEWORD(2,2),&WsaData)) == SOCKET_ERROR) { printf("ERROR: Failed to start up WinSock...\n"); return -1; } if((MyUDPSocket = socket(AF_INET,SOCK_DGRAM,0)) == SOCKET_ERROR) { printf("ERROR: Failed to create UDP socket...\n"); return -1; } SOCKADDR_IN addrLocal; addrLocal.sin_family = AF_INET;// We want to use the Internet address family addrLocal.sin_addr.s_addr = INADDR_ANY;// Use any local address addrLocal.sin_port = htons(Port); // Use arbitrary port - but the same as on other clients/servers if(SOCKET_ERROR == bind(MyUDPSocket, (LPSOCKADDR)&addrLocal,sizeof(struct sockaddr)))// Bind socket to our address { printf("ERROR: UDP bind failed..."); return -1; } // Ready to switch to multicasting mode struct ip_mreq mreq; mreq.imr_multiaddr.s_addr = inet_addr(MultiCastGrp); mreq.imr_interface.s_addr = INADDR_ANY; /******************************************************** This is where im getting the error from *********************************************************/ if((WSAProcess = setsockopt(MyUDPSocket,IPPROTO_IP,IP_ADD_MEMBERSHIP,(char*)&mreq,sizeof(mreq))) == SOCKET_ERROR) { int error = WSAGetLastError(); switch(error) { case WSAEINVAL: printf("ERROR: WSAEINVAL thrown."); break; case WSAENOTSOCK: printf("ERROR: WSAENOTSOCK thrown."); break; case WSAENOPROTOOPT: printf("ERROR: WSAENOPROTOOPT thrown."); break; } printf("ERROR: Membership failed...\n"); return -1; } /**************************************************************/ unsigned long num; if((ioctlsocket(MyUDPSocket,FIONBIO,#))==SOCKET_ERROR) { printf("ERROR: ioctlsocket() failed on UDP"); } char TTL = 32; // Restricts threshold to same site if((setsockopt(MyUDPSocket, IPPROTO_IP, IP_MULTICAST_TTL,(char *)&TTL, sizeof(TTL))) == SOCKET_ERROR) { printf("ERROR: setsockopt() failed on UDP"); } return MyUDPSocket; [edited by - Pip on December 6, 2003 2:12:09 AM] [edited by - Pip on December 6, 2003 2:15:05 AM]

The values for IP_ADD_MEMBERSHIP differ from winsock1 to winsock2. Be sure your code is seeing the correct definition from ws2tcpip.h instead of winsock.h. Your actual code looks like it should work.

How do I do that? I tried #include <ws2tcpip.h> and got alot of errors.

Make sure your system supports Winsock2 and include all the proper headers; windows.h, winsock2.h and ws2tcpip.h in that order I think. You will also have to link to the proper library, ws2_32.lib.