Writing to $ALLUSERSPROFILE

[Mark Powell]

Working on a utility for Windows that writes to 

  C:\Documents and Settings\All Users\Application Data

but it occurs to me that this would not work for non-English operating
systems.  Three questions:

- Can I use the environmental variable $ALLUSERSPROFILE with absolute
confidence that it will resolve on all Windows operating systems?
- How do I write into the "Application Data" subdirectory? (i.e. how do
I anticipate the localized name?)
- If I can't, then can I create a directory at the root of "All Users"
with absolute confidence that I can do it on all systems?

Thanks

Mark Powell