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

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

    Format

      $XABTRM  ITMLST=item-list-address,

               ITMLST_LEN=item-list-length,

               NXT=next-xab-address