regclass without error?

Hi,

Is there any way to use regclass without having ERROR?

pgpool-II needs to find the oid from table name and for the purpose it
issues something like "SELECT 'table_name'::regproc::oid". Problem is,
if the table does not exist, an error occured and the transaction
aborts. Ideally if the table does not exist, the SELECT returns 0
(InvalidOid).

Any idea?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp