FOR from query - is it a bug ?

I have function (below) that returns values in table format. But when
source table ( xxx.logic_list_item ) is empty I've got following
message in log:
"row number -1 is out of range 0..-1"

Is it a error message ? To be honest I do not know how to handle
situation when source table is empty, what should I return? In reposnse
I would like to see '0 rows found'

I'm using Postgress 8.1.

CREATE OR REPLACE FUNCTION freeconet.find_logic_items () RETURNS SETOF
xxx.logic_list_item AS $$
DECLARE
v_logic_item xxx.logic_list_item;
BEGIN

/* WYSZUKUJE logic_list_item w bazie */
FOR v_logic_item IN select * from xxx.logic_list_item LOOP
return next v_logic_item;
END LOOP;

return;

END;
$$ LANGUAGE 'plpgsql' VOLATILE;

select * from xxx.find_logic_items()

Michal Szymanski