Dblink vs calling a function that returns void

Hi,

I need to call a function via dblink that returns a void, i.e.
technically nothing.

=# select public.dblink_exec('import', 'SELECT
import.add_one_word(''word'', true)');
ERROR: statement returning results not allowed

=# select * from public.dblink('import', 'SELECT
import.add_one_word(''word'', true)') as x();
ERROR: syntax error at or near ")"
LINE 1: ...ort', 'SELECT import.add_one_word(''iphon'', true)') as x();

=# select public.dblink('import', 'SELECT import.add_one_word(''word'',
true)') as x(x void);
ERROR: syntax error at or near "("
LINE 1: ...'SELECT import.add_one_word(''iphon'', true)') as x(x void);

And, although RETURNS VOID is indistinguishable from returning a NULL:

=# select * from public.dblink('import', 'SELECT
import.add_one_word(''word'', true)') as x(x int);
ERROR: invalid input syntax for integer: ""

So, how can I do it? Besides modifying the interface of the function,
say "RETURNS int4" and using PG_RETURN_NULL()?

Best regards,
Zoltán Böszörményi

--
Bible has answers for everything. Proof:
"But let your communication be, Yea, yea; Nay, nay: for whatsoever is more
than these cometh of evil." (Matthew 5:37) - basics of digital technology.
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Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
http://www.postgresql.at/