PostgreSQL - Saber nombre y tipo de campos de un record

CREATE OR REPLACE FUNCTION buscar(

    pc_table character varying)

  RETURNS SETOF record AS

$BODY$

DECLARE

 l_rec RECORD;

BEGIN

	FOR l_rec  IN execute ' select * from '|| pc_table

	LOOP

		RETURN NEXT r;

	END LOOP;

	RETURN;

END;

$BODY$  LANGUAGE plpgsql VOLATILE  COST 100

DO

$$

DECLARE

 l_rec record;

 pc_table varchar;

BEGIN

  pc_table := 'tabla';

  FOR l_rec IN

    SELECT ordinal_position, column_name, data_type

    FROM information_schema.columns

    WHERE table_name = pc_table

  LOOP

    RAISE INFO '%',  l_rec;

  END LOOP;

END;

$$

LANGUAGE plpgsql;