OUT and INOUT work for PL/Perl but I don't see that mentioned in
E.1.3.8. General Server-Side Language Changes or in E.1.3.10. PL/Perl
Server-Side Language Changes. The former mentions only SQL and
PL/pgSQL and says that "The feature will be extended to other PLs
in due course."
CREATE FUNCTION foo(IN x integer, INOUT y integer, OUT z integer) AS $$
return {y => $_[1], z => $_[0]};
$$ LANGUAGE plperl;
SELECT * FROM foo(1, 2);
y | z
---+---
2 | 1
(1 row)
--
Michael Fuhr