You can invoke the heap analyzer during a debugging session in one of
  the following ways:

   -  In the debugger main window, choose the Run Image or Rerun Same
      items from the File menu.  When a dialog box appears, select the
      program you wish to execute and click the heap analyzer toggle
      button.

   -  At the debugger command entry prompt, enter the RUN/HEAP_ANALYZER
      or RERUN/HEAP_ANALYZER command.

   -  On VAX and Alpha systems, at the DCL prompt ($) in a DECterm window
      outside the debugger, enter the following commands and then execute
      your program:
      $ DEFINE/USER LIBRTL SYS$LIBRARY:LIBRTL_INSTRUMENTED

   -  To display the Heap Analyzer graphical display on I64 systems, at
      the DCL prompt ($) enter the command
      START HEAP_ANALYZER

  You can also invoke the heap analyzer outside a debugging session by
  entering the DEFINE/USER command detailed above, and then the DCL
  command RUN/NODEBUG.

  After you successfully invoke the heap analyzer, the heap analyzer
  startup screen appears.