UDP multicast using winsock API differences between XP and Vista

Question

It seems to be that the implementation required to set up a UDP multicast socket has changed between windows XP and windows vista. Specifically:

• Under windows X

Answer 1

Well very old question, but does someone know how to check which version of winsock is present on the machine?

I have some old machines still using xp or server 2003. But testing for the windows version does not help, it seems it is possible to have an windows version 5.1, which is not accepting the bind before, and a machine having 5.2 Version accepting it.