Access Violation When Repeatedly Opening and Closing Conferences with NetMeeting SDK (268755)


The information in this article applies to:

  • Microsoft NetMeeting 3.01 for Windows NT 4.0
  • Microsoft NetMeeting 3.01 for Windows 98 Second Edition
  • Microsoft NetMeeting 3.01 for Windows 2000
This article was previously published under Q268755

SYMPTOMS

When you use the Microsoft NetMeeting Software Development Kit (SDK) with NetMeeting 3.01 to write a NetMeeting program that repeatedly opens and closes conferences, an access violation may occur in Conf.exe.

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

283256 NetMeeting 3.01 SP2 Is Available for Some Versions of Windows

CAUSE

The access violation occurs while NetMeeting is processing a linked list of conference members to update the call roster during a close operation. NetMeeting "walks off" the end of the linked list and generates an access violation. This occurs because of a synchronization problem that makes it possible for another thread to reallocate blocks of memory released by the roster-list cleanup code before the cleanup code finishes traversing the list. This makes it impossible to determine the end of the list in the roster-list cleanup code.

RESOLUTION

To resolve this problem, obtain the latest service pack for Windows 2000. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

260910 How to Obtain the Latest Windows 2000 Service Pack

The English version of this fix should have the following file attributes or later: 
   Date        Time     Version     Size    File Name  
   ---------------------------------------------------
   1/30/2001  06:56p  4.4.0.3385  62,224    Nmcom.dll

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article. This problem was first corrected in Windows 2000 Service Pack 3.

MORE INFORMATION

Netmeeting SP2 has been released for Microsoft Windows 95, Windows 98, Windows Millennium Edition, and Windows NT 4.0. SP2 includes the fix mentioned in this KB.

NOTE: Netmeeting SP2 is not available for Windows 2000.

The English version of the Windows 2000 fix should have the following file attributes or later: 
   Date        Time   Version     Size    File Name   Platform    0S
   ------------------------------------------------------------------
   01/30/2001 18:56  4.4.0.3385  62,224   Nmcom.dll    x86       WIn2k


For more information about Netmeeting SP2, click the following link. The following file is available for download from the Microsoft Download Center:

http://www.microsoft.com/windows/netmeeting/download/nm301x86.asp

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

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Modification Type:MinorLast Reviewed:9/23/2005
Keywords:kbHotfixServer kbQFE kbAppCompatibility kbbug kberrmsg kbfix kbWin2000sp3fix KB268755
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