DMOD limited to 4 Non-RPC Callbacks for API Libraries (172479)


The information in this article applies to:

  • Microsoft SNA Server 3.0
  • Microsoft SNA Server 3.0 SP1
This article was previously published under Q172479

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.
Modification Type:MajorLast Reviewed:6/24/2004
Keywords:kbbug kbfix kbnetwork KB172479
©2004 Microsoft Corporation. All rights reserved.