file_id	IN:	File identifier returned by Hopen
	vgroup_name	IN:	Name of the vgroup

	Purpose	Returns the reference number of a vgroup given its name.
	Return value	Returns the reference number of the vgroup if successful and 0 otherwise.
	Description	Vfind searches the file identified by the parameter file_id for a vgroup with the name specified by the parameter vgroup_name, and returns the corresponding reference number.
		If more than one vgroup has the same name, Vfind will return the reference number of the first one.

	FORTRAN	integer function vfind(file_id, vgroup_name)
		integer file_id
		character*(*) vgroup_name