Returning SETOF RECORD

Hi, Im trying to return a setof record (plpgsql) but this error message
appears and i dont know what to do.
ERROR: A column definition list is required for functions returning
RECORD

The function is the following (there may or may not be data in the
table(s)) right now there is no data in the table (it should return
null or something).

DECLARE
Libro ALIAS FOR $1;
Refe ALIAS FOR $2;
res RECORD;
BEGIN
FOR res IN select color, alto, ancho from referencias where
IdReferencia like Refe and IdLibro like Libro LOOP
RETURN NEXT res;
END LOOP;
return;
END;

And another question, is it possible to call a function that returns a
setof anything like this:
select foo();
or the only way is
select * from foo(); ??

thanks a lot

JuanF

Begin forwarded message:

> From: "Patrick Hatcher" <PHatcher(at)macys(dot)com>
> Date: Mon Aug 25, 2003 11:39:30 AM America/Bogota
> To: pgsql-novice(at)postgresql(dot)org
> Subject: [NOVICE] Way to tell what SQL is currently running?
>
> I'm finding that some update process is holding all other transactions
> on a
> particular table. Is there a way to tell what the Update statement is
> that
> is running? I tried to use TOP, but it does not provide enough of the
> SQL
> string to help.
> TIA
>
> Patrick Hatcher
>
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 6: Have you searched our list archives?
>
> http://archives.postgresql.org
>