The following CREATE FUNCTION request specifies a CLOB as a parameter in its definition.
CREATE FUNCTION test.myudf (a CLOB, b INTEGER, c INTEGER, d CHARACTER (100)) RETURNS CHAR(50) LANGUAGE SQL DETERMINISTIC CONTAINS SQL SPECIFIC test.myudf CALLED ON NULL INPUT SQL SECURITY DEFINER COLLATION INVOKER INLINE TYPE 1 RETURN d || (SUBSTRING(a FROM b FOR c));