RPG SPECIAL exit routines

This question is a bit more technical than the usual RPG question,
but...

Before the advent of OA handlers, I had a SPECIAL exit routine for
which the original intent was to allow the programmer to use different
record lengths that suited their needs. But what I found was that I
couldn't tell (from inside the SPECIAL exit routine) what record length
the programmer had used. Thus, there was "garbage" in the "unused"
portion of the passed record area. I ended up having to force the
programmer to always code the maximum supported record length.

So my question is... Is there a way for a SPECIAL exit routine to
find out the record length used by an RPG program that invokes it
(possibly a register that points to the file control blocks)? Then, by
extension, is there a way to find out the same information within an OA
handler?

I need the first answer more than the second but the second would
come in handy, too. Thanks.

Sincerely,

Dave Clark