vdata_id	IN:	Vdata identifier returned by VSattach
	vdata_class	OUT:	Vdata class name

	Purpose	Retrieves the vdata class name, if any.
	Return value	Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.
	Description	VSgetclass retrieves the class name of the vdata identified by the parameter vdata_id and places it in the buffer vdata_class.
		Space for the buffer vdata_class must be allocated by the calling program before VSgetclass is called. The maximum length of the class name is defined by the macro VSNAMELENMAX (or 64).

	FORTRAN	integer function vsfgcls(vdata_id, vdata_class)
		integer vdata_id
		character*(*) vdata_class