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Q187642: BUG: "Out of Memory" Calling COMTI in Same MTS Pkg. as Caller

Article: Q187642
Product(s): Microsoft SNA Server
Version(s): WINDOWS:1.0 SP1,4.0 SP1
Operating System(s): 
Keyword(s): 
Last Modified: 04-DEC-2001

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The information in this article applies to:

- Microsoft COM Transaction Integrator for CICS and IMS, version 1.0 SP1, used with:
   - Microsoft SNA Server, version 4.0 SP1 
-------------------------------------------------------------------------------

SYMPTOMS
========

An "Out of Memory" error occurs when one component installed in a Microsoft
Transaction Server (MTS) package invokes a method of a COM Transaction
Integrator for CICS and IMS (COMTI) component installed in the same MTS package.
The error occurs in the COMTI component. The following conditions are met:

- A COMTI component is called from another MTS component.

- Both components are installed in the same MTS package.

- The COMTI method being called has a return value.

- Both components share MTS Object Context, for example:

        Set oComTI = GetObjectConext().CreateInstance("MyCOMTI.MyMethod")

CAUSE
=====

The pointer to the return value data is not properly initialized in the COMTI
runtime. This causes an attempt to free memory (that has not been acquired)
before handling the return value of the reply data from the host. Thus, the
COMTI component sends an Access Violation exception, which MTS receives.
Therefore, MTS destroys the hosting process (Mtx.exe). This causes a failed
method call and eventually an "Out Of Memory" error to be returned to the
caller.

WORKAROUND
==========

To work around this problem, do one of the following:

- Put the COMTI component in a different MTS package from the calling
  component. This causes a marshal to occur, and the marshaling code
  initializes pointers to all parameters (including return values).

- Do not share MTS Object Context. This causes the COMTI component to be
  created on a different thread. Therefore, a thread marshal occurs and yields
  similar results to the first workaround.

- Do not use a return value for the COMTI method; instead make the desired
  return value an output parameter, which avoids the problem.

STATUS
======

Microsoft has confirmed this to be a problem in Microsoft COM Transaction
Integrator for CICS and IMS version 1.0 SP1, included with SNA Server version
4.0 SP1.


A supported fix 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 Product
Support Services for more information.


Additional query words:

======================================================================
Keywords          :  
Technology        : kbAudDeveloper kbCOMTISearch
Version           : WINDOWS:1.0 SP1,4.0 SP1
Issue type        : kbbug
Solution Type     : kbfix

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