Views and functions returning sets of records

Hi all,
maybe it’s a naive question but I was wondering if there is any
difference, from a performance point of view, between a view and a
function performing the same task, something like:

CREATE VIEW foo AS …;
CREATE FUNCTION getfoo(int) RETURNS SETOF foo AS $$
    SELECT * FROM foo WHERE fooid = $1;
$$ LANGUAGE SQL;


Thank you
--
Giorgio Valoti