Thank you for the answers!
tig, the tool you linked does exactly what I was searching for. The included sample compiles and seems to work. Thanks!
However, in order to compare one's own files to the files in the browse list of another user, it would be nice to get the file hashes. AFAICS these are not available from the WinMX client's browse lists. So, I had a look at the Shareguard source, as it was suggested in other threads, and tried to browse a user using WPNPClient.cpp by username, Node-IP-Hash and port. This worked for the users I tested.
Does someone know if this works for all users? Or are there any limitations related to different peer caches or similar stuff?
So, what I would try to do is using the MXHook to get the users who are joining my upload queue, read the Username, NodeIP and Port from the original WinMX client, then use this information to browse the user using a second client based on Shareguard. Could this work? Or is there better way to do it?
I am asking, because it will take a lot time to build this tool due to my very limited C++ skills
It is good to know, that someone is working on a new client. I hope the client and the changes in protocol will be available before the majority of users are running on IPv6, only....
Again, thanks everyone for reading.