Tatsuo Ishii <t-ishii(at)sra(dot)co(dot)jp> writes:
> I am worried about that too. But if we stick a C-level API, how can we
> define the argument data type suitable for C string? I don't see such
> data types. Maybe you are suggesting that we should not use CREATE
> FUNCTION?
Well, you'd have to use the same cheat that's used for selectivity
estimation functions, triggers, I/O functions and everything else that
deals in internal datatypes: declare the function as taking and
returning OPAQUE. This is moderately annoying but I don't think
there's anything really wrong with it in practice.
regards, tom lane