[xml] diff between xmlDocs

[Emanuele Placidi <emanuele placidi gmail com>]

I've check briefly the online documentation, but it seems there isn't a way to compare two xmlDocs.
I'm asking here to avoid reinventing the wheel.
The problem is the following:
I have one xml configuration file which can be updated at any time, that is also when the program reading it is up and running. In case of update the program needs to check the difference between the new created xmlDoc and the one opened at the start up . In case something has changed it shall update only those changed part directly on the old xmlDoc.
Thanks in advance