;+
; Only applicable if the loaded index file has had new rows written to it.
; This method need not be used (is called internally) when working in online
; mode: filein, 'filename', /online
;
; If line mode is on (!g.line is 1) then this updates the global 
; line io object, otherwise, it sets the
; global continuum object.
;
; @examples
; <pre>
; ; note that we are NOT in online mode
; >filein, 'filename'
; ; immediatly display contents before online index file has changed
; >list
; ; call update before anything has changed
; > update
; >'Online index file has not changed'
; >list
; ; here you see the original contents of 'filename'
; ; now wait for end of next scan
; >update
; >"Online index file has 96 new lines."
; >list
; ; followed by all the contents, including last scan, of 'filename'
; ; NOTE: the same can be done using online mode:
; >filein, 'filename', /online
; ; display before end of next scan
; >list
; >'Online index file has not changed'
; ; followed by original contents
; ; wait for end of next scan
; >list
; >'Online index file has 96 new lines."
; ; followed by original + last scan contents
; </pre>
;
; @private_file
;
; @version $Id$
;-
pro update
    if (!g.line) then begin
        !g.lineio->update
    endif else begin
        !g.contio->update
    endelse
end