...
Notes
The wildcard string must be explicit. Eg. to match "L*" in :RAM.0 you will need ":RAM.0/L*". If necessary use GN_Fex to expand the non-explicit wildcard string before calling GN_Opw.
Bugs
If HL addresses segment 2 then this call will fail (B=0). Further, using segment 3 will return no matches with GN_Wfn (fetching matches of GN_Opw wildcard search specifier).
Related calls
GN_Esa, read & write to filename segments
GN_Fcm, compress a filename
GN_Fex, expand a filename
GN_Pfs, parse filename segment
GN_Prs, parse filename
GN_Wcl, close wildcard handle
GN_Wfn, fetch next match for wildcard string (handle)
GN_Wsm, match filename segment to wildcard string