vdata_id	IN:	Vdata identifier returned by VSattach
	field_index	IN:	Field index
	attr_name	IN:	Attribute name

	Purpose	Returns the index of an attribute of a vdata or vdata field.
	Return value	Returns the index of the attribute if successful and FAIL (or -1) otherwise.
	Description	VSfindattr returns the index of the attribute with the name specified by the parameter attr_name in the vdata identified by the parameter vdata_id.
		To return the index of the attribute attached to the vdata , set the value of the parameter field_index to _HDF_VDATA (or -1). To return the index of the attribute of a field in the vdata , set the value of the parameter field_index to the field index. Valid values of field_index range from 0 to the total number of the vdata fields - 1. The number of the vdata fields is returned by VFnfields.

	FORTRAN	integer function vsffdat(vdata_id, field_index, attr_name)
		integer vdata_id, field_index
		character*(*) attr_name