DOCUMENT:Q190067  07-AUG-1998  [vbwin]
TITLE   :BUG: Object References Might Not Be Released Properly
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:WINDOWS:6.0;
OPER/SYS:WINDOWS
KEYWORDS:kbVBp600bug kbNTOS kbWinOS kbnokeyword

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---------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual Basic Learning, Professional, and Enterprise Editions
   for Windows, version 6.0
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SYMPTOMS
========

If a function call to an object returns a Variant and the Variant is not
assigned to a local variable, Visual Basic might not dereference the object
correctly. As a result, a new thread is created in the object's process
space each time the function is called.

RESOLUTION
==========

Assign the function's return value to a local variable, regardless of
whether or not it is needed.

Example
-------

The class clsMyObject has a function called MyVariantFunction that returns
a Variant:

   Public Function MyVariantFunction() As Variant

If the return result of the function is not needed, calling the function
without assigning the return value might cause new threads to be created:

   Public Sub TestFunction()
      clsMyObject.MyVariantFunction
   End Sub

To avoid the unnecessary creation of threads, assign the function's return
value to a local variable, regardless of whether or not it is needed:

   Public Sub TestFunction()
      Dim vReturnValue As Variant

      ' Although this will not be used, it guarantees proper dereferencing.
      vReturnValue = clsMyObject.MyVariantFunction
   End Sub

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed
at the beginning of this article. We are researching this bug and will post
new information here in the Microsoft Knowledge Base as it becomes
available.

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

This type of behavior usually occurs when returning variant arrays that
contain user-defined types.

Additional query words:
======================================================================
Keywords          : kbVBp600bug kbNTOS kbWinOS kbnokeyword
Version           : WINDOWS:6.0;
Platform          : WINDOWS
Issue type        : kbbug
Solution Type     : kbpending

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

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