public void set_do_overwrite_confirmation (bool do_overwrite_confirmation)
Sets whether a file chooser in gtk_file_chooser_action_save mode will present a confirmation dialog if the user types a file name that already exists.
This is false by default.
If set to true, the this will emit the confirm_overwrite signal when appropriate.
If all you need is the stock confirmation dialog, set this property to true. You can override the way confirmation is done by actually handling the confirm_overwrite signal; please refer to its documentation for the details.
whether to confirm overwriting in save mode