how to recover a domain types and constraints?

Hi list,

I intend to recover domains type (I/O) and their constraints from my DB in
order to simplify the program that access the DB (so, using types & constraints
to auto-implement them into my program.)

I already found a query to recover domain types from a function:
SELECT function_args('testaddctr', 'public');
         function_args
-------------------------------
 (0,o,"RETURN VALUE",smallint)
 (1,i,,dn_ctr)
 (2,i,,dn_ctr)
(3 rows)

But how could I know that:
dn_ctr =            smallint
dn_ctr constraints: NOT NULL & CHECK(VALUE > -1)
?

JY
--
BOFH excuse #172:
pseudo-user on a pseudo-terminal