Calls to this routine should match calls to NBS_FIND_ITEM / NBS_FIND_NTH_ITEM. After calling it, this identifier should not be used again (even though it is in fact still valid until NBS_LOSE_NOTICEBOARD is called).
[FORCE:] Unmap the item regardless of whether there are identifiers derived from this one.
[CHECK:] Check that no identifiers are derived from this one (assumed if invalid option is given).
NBS__NILID NIL ID
NBS__NOTTOPLEVEL ID is not a top-level identifier
NBS__NEVERFOUND Item was never found (or more items
have been lost than were found)
NBS__HASIDS Noticeboard has identifiers derived
from it
SS$_* System service codes from SYS$DELTVA (VMS only).
NBS The Noticeboard System