Q149747: PRB: Debugger Cannot Evaluate Out of Scope Named Constants

Article: Q149747
Product(s): Microsoft Fortran Compiler
Version(s): 4.0
Operating System(s): 
Keyword(s): kbFortranPS kbLangFortran
Last Modified: 03-NOV-1999

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The information in this article applies to:

- Microsoft Fortran PowerStation for Windows 95 and Windows NT, version 4.0 
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SYMPTOMS
========

The debugger's watch window cannot evaluate expressions that contain named
constants that have gone out of scope. Attempting to use a variable evaluation
expression containing a locally undefined named constant in one of the watch
windows causes the message "EE2347: Undefined variable" to be returned in the
corresponding value field.

STATUS
======

This behavior is by design.

MORE INFORMATION
================

The scope context operator allows you to view information about module variables
that have gone out of scope. However, using the scope context operator in this
manner does not apply to named constants. You cannot use the scope context
operator to evaluate named constants.

Steps to Illustrate Behavior
----------------------------

1. Build the sample code provided in Developer Studio.

2. After successfully building the sample code, start a debugging session by
  selecting Debug from the Build menu and then choosing Step Into.

3. Step into the module subroutine MODULE_PROC. In a watch window, type:

  " MY_MODULE::MODULE_PROC::Y" (without the quotation marks)

  The number 9.00000 is correctly displayed for the named constant Y.

4. Step into the internal module subroutine INTERNAL_PROC to the assignment
  statement of variable N. Note that the watch expression created in Step 3 is
  no longer valid because it references the named constant Y which is out of
  scope.

5. In the subroutine INTERNAL_PROC, evaluate the variables H and N and the named
  constant Y. In a watch window, do the following:

  To evaluate H using the scope context operator, type:

  " {MY_MODULE::MODULE_PROC::INTERNAL_PROC}H" (without the quotation marks)

  To evaluate N using the scope context operator, type:

  " {MY_MODULE::MODULE_PROC::INTERNAL_PROC}N" (without the quotation marks)

  Evaluation of Y will fail when out of scope or when using the scope context
  operator.

  Using the scope context operator, type:

  " {MY_MODULE::MODULE_PROC::INTERNAL_PROC}Y" (without the quotation marks)

  -or-

  Without the scope context operator, type:

  " MY_MODULE::MODULE_PROC::INTERNAL_PROC::Y" (without the quotation marks)

NOTE: "EE2347: Undefined variable" is generated for the named constant Y. The
value of the named constant Y can only be viewed while control is in the
MODULE_PROC subroutine.

Sample Code
-----------

  ! Compile options needed: /Zi
        MODULE MY_MODULE
          INTEGER H
        CONTAINS
          SUBROUTINE MODULE_PROC
            PARAMETER(Y=9.0)
            CALL INTERNAL_PROC
          CONTAINS
              SUBROUTINE INTERNAL_PROC
                INTEGER N
                N = Y + H
              END SUBROUTINE INTERNAL_PROC
          END SUBROUTINE MODULE_PROC
        END MODULE MY_MODULE

        PROGRAM TEST
          USE MY_MODULE
          CALL MODULE_PROC
        END PROGRAM TEST

Additional query words: 4.00

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Keywords          : kbFortranPS kbLangFortran 
Technology        : kbAudDeveloper kbPTProdChange kbFortranSearch kbFORTRANPower400NT
Version           : :4.0

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