The TPU$CONTROL routine is the main processing routine of the
    TPU editor. It is responsible for reading the text and
    commands and executing them. When you call this routine (after
    calling TPU$INITIALIZE), control is turned over to TPU.

    Format

      TPU$CONTROL  [integer]

1  –  Returns

    OpenVMS usage:cond_value
    type:         longword (unsigned)
    access:       write only
    mechanism:    by value

    Longword condition value. Most utility routines return a
    condition value in R0. Condition values that this routine can
    return are listed under Condition Values Returned.

2  –  Argument

 integer

    OpenVMS usage:integer
    type:         longword (unsigned)
    access:       read only
    mechanism:    by reference
    Prevents TPU from displaying the message "Editing session is
    not being journaled" when the calling program gives control to
    TPU. Specify a true (odd) integer to preserve compatibility in
    future releases. If you omit the parameter, TPU displays the
    message if journaling is not enabled.

3  –  Description

    This routine controls the editing session. It is responsible for
    reading the text and commands and for executing them. Windows on
    the screen are updated to reflect the edits made. Your program
    can regain control by interrupting TPU using the TPU$SPECIFY_
    ASYNC_ACTION routine, together with the TPU$TRIGGER_ASYNC_ACTION
    routine.

                                   NOTE

       Control is also returned to your program if an error occurs
       or when you enter either the built-in procedure QUIT or the
       built-in procedure EXIT.

4  –  Condition Values Returned

    TPU$_EXITING       A result of EXIT (when the default condition
                       handler is established).
    TPU$_NONANSICRT    A result of operation termination - results
                       when you call TPU with TPU$DISPLAYFILE
                       set to nodisplay and you attempt to execute
                       screen-oriented commands.
    TPU$_QUITTING      A result of QUIT (when the default condition
                       handler is established).
    TPU$_RECOVERFAIL   A recovery operation was terminated
                       abnormally.