Is record handle available to a check constraint stored procedure call?

v8.3.4 on Linux

I have a check constraint on a column.  The constraint decides pass/fail based on the returned status of a stored procedure call that returns either "OK" or "NO".  So when the stored procedure is called, there's a living attempt to insert or update a record.

Question:  Is there a handle on the record being inserted or updated?  Something like what's available in a trigger function (new.col1, old.col2, etc...)?  If so, what does it look like?

Thanks in Advance