VMS Help RMS, RMS Control Block Macros, $XABITM  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The $XABITM macro allocates and initializes a XABITM. No value is
    returned for this assembly-time operation.

    Format

      $XABITM  ITEMLIST=item-list-address,

               MODE={sensemode|setmode},

               NXT=next-xab-address