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Q170288: CMWAIT Returns Incorrectly After Canceling CMALLC

Article: Q170288
Product(s): Microsoft SNA Server
Version(s): WINDOWS:2.11,2.11 SP1,2.11 SP2,3.0,3.0 SP1
Operating System(s): 
Keyword(s): kbnetwork kbprogramming
Last Modified: 13-JUN-2001

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The information in this article applies to:

- Microsoft SNA Server, versions 2.11, 2.11 SP1, 2.11 SP2, 3.0, 3.0 SP1 
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SYMPTOMS
========

When you use the SNA Server Win32 asynchronous CPIC interface, a CPIC
application may encounter problems when you cancell an Allocate (CMALLC) call
with Cancel_Conversation (CMCANC).

After you cancel a CMALLC using CMCANC, subsequent attempts to issue CMALLC in
non-blocking mode appear to show that CMWAIT returns immediately, without
waiting for the CMALLC async final completion.

CAUSE
=====

Canceling an asynchronous CPI-C call (not ones that would complete by posting a
Windows message) does not work correctly. Later CMWAITs return early because
they pick up false completions from the cancelled calls.

STATUS
======

Microsoft has confirmed this to be a problem in SNA Server versions 2.11, 2.11
Service Pack 1 (SP1), 2.11 Service Pack 2 (SP2), 3.0, and 3.0 Service Pack 1
(SP1).

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):

  S E R V P A C K


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.


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

The following sequence was observed in an SNA Application CPIC API trace:

  CMINIT ->
     <- CMINIT OK
  CMSPM (set non-blocking mode)
     <- CMSPM OK
  CMALLC ->
     <- CMALLC (operation incomplete)
  CMCANC ->
     <- CMALLC (allocation_failure_no_retry)
     <- CMCANC OK
  CMINIT ->
     <- CMINIT OK
  CMSPM (set non-blocking mode) ->
     <- CMSPM OK
  CMALLC ->
     <- CMALLC (operation incomplete)
  CMWAIT ->
     <- CMWAIT OK
  CMDEAL ->
     <- CMDEAL (error = state_check)
     <- CMALLC OK

Additional query words:

======================================================================
Keywords          : kbnetwork kbprogramming 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ300 kbSNAServ211 kbSNAServ211SP1 kbSNAServ211SP2 kbSNAServ300SP1
Version           : WINDOWS:2.11,2.11 SP1,2.11 SP2,3.0,3.0 SP1
Issue type        : kbbug
Solution Type     : kbfix

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