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Q168380: BUG: Incorrect Evaluation of Static Member Functions in Debugge

Article: Q168380
Product(s): Microsoft C Compiler
Version(s): winnt:4.0,4.1,4.2,5.0,6.0
Operating System(s): 
Keyword(s): kbtool kbDebug kbide kbVC400bug kbVC410bug kbVC420bug kbVC500bug kbvfp600bug
Last Modified: 06-MAY-2001

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The information in this article applies to:

- The Integrated Debugger, used with:
   - Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Professional Edition, version 4.2 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 5.0 
   - Microsoft Visual C++, 32-bit Enterprise Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, version 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

Function evaluation of static member functions cannot be done in the Watch or
the QuickWatch window of the debugger. You a wrong value, or get the following
error message:

  Error:cannot display value

CAUSE
=====

The expression evaluator in the debugger does not properly distinguish between
static and non-static methods. The first case listed above appears to be an
evaluation of a method without a "this" pointer, hence, we get an "Error:cannot
display value" message. The second case occurs because the debugger is not
properly distinguishing between static and non-static member functions. The
"this" pointer is pushed onto the stack to evaluate the static member function,
which is incorrect.

RESOLUTION
==========

There is no workaround. Do not attempt to evaluate static member functions from
within the debugger, either in the watch or quick watch window.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.

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

Steps to Reproduce Behavior
---------------------------

Use the following sample code and build it with debug information:

      class A
      {
        public:
        static int bar (int i) {return i;}
      };

      void main ()
      {
        A  f;
        int j = A::bar(200);
        int i = f.bar(100);
      }

Start the debugger by stepping into (F11 key) function "main." In the Watch or
QuickWatch window, type A::bar(200) and you will get the error message described
in the SYMPTOMS section. Typing f.bar(100) produces a wrong value.

Additional query words:

======================================================================
Keywords          : kbtool kbDebug kbide kbVC400bug kbVC410bug kbVC420bug kbVC500bug kbvfp600bug 
Technology        : kbVCsearch kbAudDeveloper kbIntegratedDebugger
Version           : winnt:4.0,4.1,4.2,5.0,6.0
Issue type        : kbbug

=============================================================================

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