file_id	IN:	File identifier returned by Hopen
	vdata_name	IN:	Name of the vdata

	Purpose	Returns the reference number of a vdata, given its name.
	Return value	Returns the vdata reference number if successful and 0 if the vdata is not found or an error occurs.
	Description	VSfind returns the reference number of the vdata with the name specified by the parameter vdata_name in the file specified by the parameter file_id. If there is more than one vdata with the same name, VSfind will only find the reference number of the first vdata in the file with that name.

	FORTRAN	integer function vsffnd(file_id, vdata_name)
		integer file_id
		character*(*) vdata_name