VMS Help DEBUG, Heap Analyzer  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The Heap Analyzer provides a graphical representation of memory
    use in real time. This allows you to quickly identify inefficient
    memory usage in your application such as allocations that are
    made too often, memory blocks that are too large, fragmentation,
    or memory leaks.

    For details on running the Heap Analyzer from within the
    debugger, refer to the OpenVMS Debugger Manual.

    To run the standalone Heap Analyzer, issue the following
    commands:

    $ DEFINE/USER/NAME=CONFINE LIBRTL SYS$LIBRARY:LIBRTL_INSTRUMENTED
    $ RUN/NODEBUG program