gnome_dialog_run return values?

[Dietmar Maurer <dm vlsivie tuwien ac at>]

gnome_dialog_run returns the number of the button the user pressed, or
-1 if no button is pressed.  I have a dialog with a CList and want that
the double click on a list item ends the dialog, executing the same
action as the OK button -> gnome_dialog_run should return the number of
the OK button (or any user defined number) if the user double click on a
list item. How can I accomplish that?