vgroup_id	IN:	Vgroup identifier returned by Vattach
	vgroup_class	IN:	Class name of a vgroup

	Purpose	Sets the class name of a vgroup.
	Return value	Returns SUCCEED (or 0) if successful and FAIL (or -1) otherwise.
	Description	Vsetclass sets the class name specified by the parameter vgroup_class to the vgroup identified by the parameter vgroup_id.
		A vgroup initially has a class name of NULL. The class name may be set more than once. Class names, like vgroup names, can be of any character strings. They exist solely as meaningful labels for user applications.
		The class name is limited to VSNAMELENMAX (or 64) characters.

	FORTRAN	integer function vfscls(vgroup_id, vgroup_class)
		integer vgroup_id
		character*(*) vgroup_class