how do i create trigger with params?

i would like to create c-type trigger which is used with params.
so i created function:
CREATE function dfti(text) RETURNS opaque as
'/home/users/pgdba/work/lib/dfti.so' language 'C';
o.k. created
byt when i try to:
CREATE trigger dfti_trg after INSERT or UPDATE or DELETE on newstexts for each
row execute procedure dfti ('newstexts');
i get:
psql:create.sql:9: ERROR: CreateTrigger: function dfti() does not exist

which is of course true. function dfti() doesn't exist, but i wanted to use
dfti(text)!

if i change function creation not to have (text) trigger is properly created,
but it fails (killing backend) on insert.
what did i wrong?

depesz

--
hubert depesz lubaczewski http://www.depesz.pl/
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