Queues an asynchronous system trap (AST) for the calling access
    mode or for a less privileged access mode.

    On Alpha and Integrity server systems, this service accepts 64-
    bit addresses.

    Format

      SYS$DCLAST  astadr ,[astprm] ,[acmode]

    C Prototype

      int sys$dclast  (void (*astadr)(__unknown_params), unsigned

                      __int64 astprm, unsigned int acmode);