Q166215: INFO: Modifying VTables with AddressOf Is Not Supported

Article: Q166215
Product(s): Microsoft Visual Basic for Windows
Version(s): 5.0
Operating System(s): 
Keyword(s): kbpolicy kbVBp500 kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Control Creation Edition for Windows, version 5.0 
- Microsoft Visual Basic Learning Edition for Windows, version 5.0 
- Microsoft Visual Basic Professional Edition for Windows, version 5.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 
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SUMMARY
=======

In the March 1997 issue of the Visual Basic Programmer's Journal, an article by
Matthew Curland and William Storage was published which featured a technique for
simulating the calling of function pointers in Microsoft Visual Basic 5.0.

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

As described in the article, the technique requires modification of a class's
VTable through the use of the AddressOf operator and the CopyMemory and
VirtualProtect Win32 API functions.

Modifying VTables and the technique described in the article are not supported by
Microsoft.

Visual Basic Programmer's Journal is published by Fawcette Technical
Publications, a publisher independent of Microsoft; we make no warranty, implied
or otherwise, regarding this publication's content or reliability.


REFERENCES
==========

Visual Basic Programmer's Journal
Fawcette Technical Publications
March 1997, Volume 7, No. 3
"Modifying vtables with AddressOf." (pgs 131-133)

Additional query words: Vtables pointer recursive recursion hack sort qsort compare void overwrite

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Keywords          : kbpolicy kbVBp500 kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500Search kbVBA500 kbVB500 kbZNotKeyword3
Version           : 5.0
Issue type        : kbinfo

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