if sendRecvMsgFunc.err != nil {
			return
		}
		defer syscall.CloseHandle(s)
		var n uint32
		sendRecvMsgFunc.err = syscall.WSAIoctl(s,
			syscall.SIO_GET_EXTENSION_FUNCTION_POINTER,
			(*byte)(unsafe.Pointer(&WSAID_WSARECVMSG)),
			uint32(unsafe.Sizeof(WSAID_WSARECVMSG)),
			(*byte)(unsafe.Pointer(&sendRecvMsgFunc.recvAddr)),