/sys$common/syshlp/DBG$HELP.HLB  —  DEBUG  DECLARE
    Declares a formal parameter within a command procedure. This
    enables you to pass an actual parameter to the procedure when
    entering an execute procedure (@) command.

    Format

      DECLARE  p-name:p-kind [,p-name:p-kind[, . . . ]]

1  –  Parameters

 p-name

    Specifies a formal parameter (a symbol) that is declared within
    the command procedure.

    Do not specify a null parameter (represented either by two
    consecutive commas or by a comma at the end of the command).

 p-kind

    Specifies the parameter kind of a formal parameter. Valid
    keywords are as follows:

    ADDRESS   Specifies that the actual parameter is interpreted
              as an address expression. Same effect as
              DEFINE/ADDRESS symbol-name = actual-parameter.
    COMMAND   Specifies that the actual parameter is
              interpreted as a command. Same effect as
              DEFINE/COMMAND symbol-name = actual-parameter.
    VALUE     Specifies that the actual parameter is interpreted as a
              value expression in the current language. Same effect
              as DEFINE/VALUE symbol-name = actual-parameter.

2  –  Description

    The DECLARE command is valid only within a command procedure.

    The DECLARE command binds one or more actual parameters,
    specified on the command line following the execute procedure
    (@) command, to formal parameters (symbols) declared within a
    command procedure.

    Each p-name:p-kind pair specified by a DECLARE command binds one
    formal parameter to one actual parameter. Formal parameters are
    bound to actual parameters in the order in which the debugger
    processes the parameter declarations. If you specify several
    formal parameters on a single DECLARE command, the leftmost
    formal parameter is bound to the first actual parameter, the
    next formal parameter is bound to the second, and so on. If you
    use a DECLARE command in a loop, the formal parameter is bound
    to the first actual parameter on the first iteration of the loop;
    the same formal parameter is bound to the second actual parameter
    on the next iteration, and so on.

    Each parameter declaration acts like a DEFINE command: it
    associates a formal parameter with an address expression, a
    command, or a value expression in the current language, according
    to the parameter kind specified. The formal parameters themselves
    are consistent with those accepted by the DEFINE command and can
    in fact be deleted from the symbol table with the DELETE command.

    The %PARCNT built-in symbol, which can be used only within a
    command procedure, enables you to pass a variable number of
    parameters to a command procedure. The value of %PARCNT is the
    number of actual parameters passed to the command procedure.

    Related commands:

       @ (Execute Procedure)
       DEFINE
       DELETE

3  –  Examples

    1.! ***** Debugger Command Procedure EXAM_GO.COM *****
      DECLARE L:ADDRESS, M:COMMAND
      EXAMINE L; M

      DBG> @EXAM_GO X "@DUMP"

      In this example, the command procedure EXAM_GO.COM accepts two
      parameters, an address expression (L)  and a command string
      (M).  The address expression is then examined and the command
      is executed.

      At the debugger prompt, the @EXAM_GO X "@DUMP" command executes
      EXAM_GO.COM, passing the address expression X and the command
      string @DUMP.

    2.! ***** Debugger Command Procedure VAR.DBG *****
      SET OUTPUT VERIFY
      FOR I = 1 TO %PARCNT DO (DECLARE X:VALUE; EVALUATE X)
      DBG> @VAR.DBG 12,37,45
      %DEBUG-I-VERIFYIC, entering command procedure VAR.DBG
       FOR I = 1 TO %PARCNT DO (DECLARE X:VALUE; EVALUATE X)
      12
      37
      45
      %DEBUG-I-VERIFYIC, exiting command procedure VAR.DBG
      DBG>

      In this example, the command procedure VAR.DBG accepts a
      variable number of parameters. That number is stored in the
      built-in symbol %PARCNT.

      At the debugger prompt, the @VAR.DBG command executes VAR.DBG,
      passing the actual parameters 12, 37, and 45. Therefore,
      %PARCNT has the value 3, and the FOR loop is repeated 3
      times. The FOR loop causes the DECLARE command to bind each
      of the three actual parameters (starting with 12) to a new
      declaration of X. Each actual parameter is interpreted as a
      value expression in the current language, and the EVALUATE X
      command displays that value.
Close Help