DOCUMENT:Q172479  02-APR-2000  [sna]
TITLE   :DMOD limited to 4 Non-RPC Callbacks for API Libraries
PRODUCT :Microsoft SNA Server
PROD/VER:WINDOWS:3.0,3.0 SP1
OPER/SYS:
KEYWORDS:kbnetwork

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The information in this article applies to:

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

When an application calls the Microsoft SNA Server APIs and these functions need
to register a callback, the application will fail when it tries to register more
than four callbacks.

CAUSE
=====

The Microsoft SNA Server DMOD component is limited to four non-RPC callback
routines for API libraries per process.

STATUS
======

Microsoft has confirmed this to be a problem in SNA Server versions 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


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

When an application needs to perform its own routing of received messages, the
DMOD adds the specified procedure to a list of procedures called whenever a
message is received.

The following example will illustrate a failing situation:

When an application issues the following function calls,

   sli_open();
   acssvc_convert();
   appc_display();

the sequence of registring callback routines is as follows:

   RPC registers a callback, rout_cnt (the count of callbacks
      registered) = 1
   RUI registers a callback, rout_cnt = 2
   CSV registers a callback, rout_cnt = 3
   APPC registers a callback (for conversation verbs), rout_cnt = 4

   APPC tries to register another callback (for DISPLAY & CNOS management
      verbs)

The DMOD fails this request and the DISPLAY verb fails, because it already has
four callbacks registered.


Additional query words: route

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Keywords          : kbnetwork 
Technology        : kbAudDeveloper kbSNAServSearch kbSNAServ300 kbSNAServ300SP1
Version           : WINDOWS:3.0,3.0 SP1
Issue type        : kbbug
Solution Type     : kbfix

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