Q189772: FIX: GETPEM() Function Does Not Return the Correct ParentClass

Article: Q189772
Product(s): Microsoft FoxPro
Version(s): WINDOWS:5.0,5.0a
Operating System(s): 
Keyword(s): 
Last Modified: 11-DEC-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a 
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SYMPTOMS
========

If you use the GETPEM() function to return the value of the ParentClass property
of an instantiated class, you might get incorrect results. The return value
might be the ParentClass from another class in the class hierarchy, or might be
empty when it should have a value.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This has been corrected in Visual FoxPro 6.0.

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

You use the GETPEM() function to return values of properties, or code from
events/methods of any classes or objects in memory. The GETPEM() function
requires two parameters. First, you pass it an object reference or the name of a
class. Second, you pass it a property, event, or method name.

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

1. Run the following code from a program (.prg) file:

        CLEAR
        CLEAR ALL
        oMe = CREATEOBJECT( "Son" )
        cClass = oMe.CLASS

        DO WHILE NOT(EMPTY(cClass))
           ?cClass + ' was begotten by ' + GETPEM(cClass, "ParentClass")
           cClass = GETPEM(cClass, "ParentClass")
        ENDDO

        DEFINE CLASS granddad AS CUSTOM
        ENDDEFINE

        DEFINE CLASS Dad AS granddad
        ENDDEFINE

        DEFINE CLASS Son AS Dad
        ENDDEFINE

RESULT: If you run the code under Visual FoxPro 5.0x, the program returns the
following to the desktop:

  Son was begotten by Granddad
  Granddad was begotten by

This is incorrect. The correct return values are:

  Son was begotten by Dad
  Dad was begotten by Granddad
  Granddad was begotten by Custom
  Custom was begotten by

Additional query words: kbVFp500abug kbVFp600fix kbOOP

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Keywords          :  
Technology        : kbVFPsearch kbAudDeveloper kbVFP500 kbVFP500a
Version           : WINDOWS:5.0,5.0a
Issue type        : kbbug
Solution Type     : kbfix

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