Invalid Page Fault in Wappc32.dll Using WinAPPCSetBlockingHook (175778)
The information in this article applies to:
- Microsoft SNA Server 2.11
- Microsoft SNA Server 2.11 SP1
- Microsoft SNA Server 2.11 SP2
- Microsoft SNA Server 3.0
- Microsoft SNA Server 3.0 SP1
- Microsoft SNA Server 3.0 SP2
This article was previously published under Q175778 SYMPTOMS
A 32-bit APPC application that initiates multiple conversations and uses
the WinAPPCSetBlockingHook() call causes a general protection fault (GP
fault) in Wappc32.dll on a computer running Windows 95 and using the SNA
Server Client for Windows 95. The GP fault will be similar to the
following:
This program has performed an illegal operation and will be shut down.
If the problem persists, contact the program vendor.
<Program Name> caused an invalid page fault in module WAPPC32.DLL at
<memory location>.
Registers:
..data omitted..
CAUSE
The 32-bit APPC library does not correctly handle the case where the
WinAPPCSetBlockingHook() call returns FALSE on multiple threads.
WORKAROUND
If the WinAPPCSetBlockingHook() call is being used to cancel one
conversation when the MC_ALLOCATE() takes too long. The application should
call WinAPPCCancelBlockingCall() from within the WinAPPCSetBlockingHook()
call. If this is done, the WinAPPCSetBlockingHook() call would continue to
return TRUE instead of FALSE.
Another alternative is to have the application use the Asynchronous APPC
API and the WinAPPCCancelAsyncRequest() call.
Please refer to the SNA Server "APPC Programmer's Guide" for more details
on the APPC functions mentioned in this article.
STATUS
Microsoft has confirmed this to be a problem in SNA Server versions 2.11,
2.11 Service Pack 1, 2.11 Service Pack 2, 3.0, 3.0 Service Pack 1, 3.0
Service Pack 2.
The 32-bit APPC library has been updated to correctly handle cases where a
WinAPPCSetBlockingHook() call returns FALSE. The updated module is
Wappc32.dll.
This problem was corrected in the latest SNA Server version 3.0 U.S.
Service Pack. For information on obtaining this Service Pack, query on
the following word in the Microsoft Knowledge Base (without the spaces):
A supported fix for SNA Server version 2.11 is now available, but has not
been fully regression tested and should be applied only to systems
experiencing this specific problem. Unless you are severely impacted by
this specific problem, Microsoft recommends that you wait for the next
Service Pack that contains this fix. Contact Microsoft Technical Support
for more information.
| Modification Type: | Minor | Last Reviewed: | 9/22/2005 |
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| Keywords: | kbHotfixServer kbQFE kbbug kbfix KB175778 |
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