No special API call. The folder should be present on all Mac's and is always called /Users/Shared/, even when the Mac is set-up for another language.
If it's not there, then I use Brucey's Special Folder mod to retrieve the user's own folder and store the files there instead.
If it's not there, then I use Brucey's Special Folder mod to retrieve the user's own folder and store the files there instead.