Reads or writes the position of the top-left corner of a file's icon.
MacOS X systems have no good API for the desktop manager yet. This function reported to not works on OS X systems at least up to OS X 10.4.x. It might start working on later OS X systems if the desktop manager gets fixed. All current MacOS X systems are returning 0:0 here.
Linux and Windows systems have no concept for file labels so this function is not supported on those platforms. It is perfectly valid to call this function on the unsupported platforms but it will only return nil there.