> [...]
> But it is incomplete specially without the referenced
> example (can't find uchar.c on the web anymore).

   Perhaps, but the discussion does mention fib$w_verlimit.  I know
nothing, but I'd guess that that is the key.

   That particular FIB field is not used in UnZip, but UnZip's
[.vms]vms.c _does_ use a FIB (with sys$parse(), sys$assign(), and
sys$qiow()).  You'd need to do some work to adapt the relevant UnZip
code for this purpose -- It always does IO$_CREATE, for example, and it
has all the extra stuff needed for ODS5 extended names -- but it might
give you a start.

   If using a FIB is your biggest problem, then another search for, say,
"fibdef", might find more useful stuff than a search for "uchar.c".