When entered from DCL level, Ctrl/Y interrupts an image that is
    running without debugger control, enabling you then to start the
    debugger with the DCL command DEBUG.

                                  NOTES

       Do not use Ctrl/Y from within a debugging session. Instead,
       use Ctrl/C or an equivalent abort-key sequence established
       with the SET ABORT_KEY command.

       When you start the debugger with the Ctrl/Y-DEBUG sequence,
       you cannot then use the debugger RUN or RERUN commands.

    Format

      <Ctrl/Y>

1  –  Description

    Pressing Ctrl/Y at DCL level enables you to interrupt an image
    that is running without debugger control, so that you can then
    start the debugger with the DCL command DEBUG.

    You can bring an image under debugger control only if, as a
    minimum, that image was linked with the /TRACEBACK qualifier
    (/TRACEBACK is the default for the LINK command).

    When you press Ctrl/Y to interrupt the image's execution, control
    is passed to DCL. If you then enter the DCL command DEBUG, the
    interrupted image is brought under control of the debugger. The
    debugger sets its language-dependent parameters to the source
    language of the module in which execution was interrupted and
    displays its prompt. You can then determine where execution was
    suspended by entering a SHOW CALLS command.

    The Ctrl/Y-DEBUG sequence is not supported in the kept debugger
    configuration.

    The Ctrl/Y-DEBUG sequence is not supported in the VSI DECwindows
    Motif for OpenVMS user interface to the debugger. Instead, use
    the STOP button.

    Within a debugging session, you can use the CONNECT command to
    connect an image that is running without debugger control in
    another process (of the same job) to that debugging session.

    Related commands:

       CONNECT
       Ctrl/C
       DEBUG (DCL command)
       RUN (DCL command)

2  –  Examples

    1.$ RUN/NODEBUG TEST_B
           . . .
          <Ctrl/Y>
      Interrupt
      $ DEBUG

                 Debugger Banner and Version Number

      Language: ADA, Module: SWAP
      DBG>

      In this example, the RUN/NODEBUG command executes the image
      TEST_B without debugger control. Execution is interrupted
      with Ctrl/Y. The DEBUG command then causes the debugger to be
      started. The debugger displays its banner, sets the language-
      dependent parameters to the language (Ada, in this case) of the
      module (SWAP) in which execution was interrupted, and displays
      the prompt.

    2.$ RUN/NODEBUG PROG2
           . . .
          <Ctrl/Y>
      Interrupt
      $ DEBUG

                 Debugger Banner and Version Number

      Language: FORTRAN, Module: SUB4
      predefined trace on activation at SUB4\%LINE 12 in %PROCESS_NUMBER 1
      DBG>

      In this example, the DEFINE/JOB command establishes a
      multiprocess debugging configuration. The RUN/NODEBUG command
      executes the image PROG2 without debugger control. The Ctrl/Y-
      DEBUG sequence interrupts execution and starts the debugger.
      The banner indicates that a new debugging session has been
      started. The activation tracepoint indicates where execution
      was interrupted when the debugger took control of the process.