vgroup_id	IN:	Vgroup identifier returned by Vattach
	field_name_list	IN:	List of field names

	Purpose	Locates a vdata in a vgroup given a list of field names.
	Return value	Returns the reference number of the vdata if successful and FAIL (or -1) otherwise.
	Description	Vflocate searches the vgroup identified by the parameter vgroup_id for a vdata that contains all of the fields listed in the parameter field_name_list. If that vdata is found, Vflocate will return its reference number.

	FORTRAN	integer function vffloc(vgroup_id, field_name)
		integer vgroup_id
		character*(*) field_name