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Q305661: Retried COM Function Calls Using IMessageFilter May Cause a Leak

Article: Q305661
Product(s): Microsoft Windows NT
Version(s): 4.0
Operating System(s): 
Keyword(s): kbenv
Last Modified: 08-MAY-2002

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The information in this article applies to:

- Microsoft Windows NT Workstation version 4.0 
- Microsoft Windows NT Server version 4.0 
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SYMPTOMS
========

An event handle leak and a memory leak may occur when you are using
IMessageFilter to handle incoming COM calls. Use the hotfix that is described in
this article only if all of the following conditions exist:

- The client implements IMessageFilter and SERVERCALL_RETRYLATER is returned in
  the implemented IMessageFilter::HandleInComingCall function.

- The IMessageFilter::HandleInComing call in the client is called as a result
  of the COM layer synchronizing calls because of cross-apartment
  communication. An example of this is a single-threaded apartment (STA) client
  process calling out a multiple-threaded apartment (MTA) COM server process
  and the MTA COM server process calling back into the STA client process

- The client that implements IMessageFilter is running on Windows NT 4.0. If
  the client is running on Microsoft Windows 2000, the leak does not occur.

- The client process has a visible handle leak that you can observe by using a
  process-monitoring tool such as Windows Task Manager.

- The client process has a visible memory leak that you can observe by using a
  process-monitoring tool such as Windows Task Manager.

CAUSE
=====

This issue is caused by a problem in the COM run-time in Windows NT 4.0.

RESOLUTION
==========

A supported fix is now available from Microsoft, but it is only intended to
correct the problem described in this article and should be applied only to
systems experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the
fix. For a complete list of Microsoft Product Support Services phone numbers and
information on support costs, please go to the following address on the World
Wide Web:

  http://support.microsoft.com/default.aspx?scid=fh;EN-US;CNTACTMS

NOTE: In special cases, charges that are normally incurred for support calls may
be canceled, if a Microsoft Support Professional determines that a specific
update will resolve your problem. Normal support costs will apply to additional
support questions and issues that do not qualify for the specific update in
question.

The English version of this fix should have the following file attributes or
later:

  Date         Time   Version        Size       File name  Platform
  -----------------------------------------------------------------
  29-Aug-2001  20:44  4.0.1381.7102    701,200  Ole32.dll  i386
  29-Aug-2001  20:44  4.0.1381.7102    107,280  Rpcss.exe  i386
  24-Aug-2001  03:26  4.0.1381.7102  1,239,824  Ole32.dll  Alpha
  24-Aug-2001  03:26  4.0.1381.7102    183,568  Rpcss.exe  Alpha

NOTE: Because of file dependencies, this hotfix requires Microsoft Windows NT 4.0
Service Pack 6a.



STATUS
======

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

Additional query words:

======================================================================
Keywords          : kbenv 
Technology        : kbWinNTsearch kbWinNTWsearch kbWinNTW400 kbWinNTW400search kbWinNT400search kbWinNTSsearch kbWinNTS400search kbWinNTS400
Version           : :4.0
Hardware          : ALPHA x86
Issue type        : kbbug
Solution Type     : kbfix

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