capture "changed" signal for the cell of treeview

[yu wu <vanii warem gmail com>]

I am using the followed to renderer text in cells:

++++++++++++++++++++++++

  renderer = gtk_cell_renderer_text_new();
  column = gtk_tree_view_column_new_with_attributes((local = char_to_utf8 ("weight(kg/m)")), renderer, "text", MEM_SEC_WEIGHT_PER_METER, NULL);
  g_free(local);
  gtk_tree_view_append_column(treeview, column);

++++++++++++++++++++++++

I don't set `editable' attribute for the renderer. The value for specified cell is set by 

other sub-function. Then how can I get the `changed' signal for the specified cell when its 
value is changed? My purpose is to update other widget when text value in cell is changed. 
For the text cell renderer, it only has edited signal that is not useful for my case 

(or maybe I misunderstand some points). When some cell is changed, it might have no 
any selection. That's, the `changed' signal for selection has no use here.

Please help.