DOCUMENT:Q130719  25-JUL-2001  [visualc]
TITLE   :FIX: "Unable to Create File Buffer" 32-Bit ODBC Error
PRODUCT :Microsoft C Compiler
PROD/VER:1.50 1.51 1.52 1.52a | 2.00 2.10
OPER/SYS:
KEYWORDS:kbDatabase kbMFC kbODBC kbVCkbbuglist kbfixlist

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The information in this article applies to:

 - The Microsoft Foundation Classes (MFC), included with:
    - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.5, 1.51, 1.52 
    - Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 2.2 
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SYMPTOMS
========

After a long period of successful operation, an application generates the
following ODBC error when that application uses the MFC database classes such
that the 32-bit ODBC cursor library:

   General error: Unable to create file buffer
   State:S1000,Native:0,Origin:[Microsoft][ODBC Cursor Library]

CAUSE
=====

The ODBC cursor library generates temporary files for its own use. To ensure
that the temporary file names are unique, the 32-bit ODBC cursor library
generates temporary file names that include a hex number. That number is
incremented every time a new filename is generated. Here is an example of
filenames that are genrated by the cursor library for its temporary files:

   CTT1111.TMP
   CTT1112.TMP
   CTT1113.TMP

When the hex number embedded in the filename wraps from FFFF to 0, the error is
generated:

   CTTFFFD.TMP
   CTTFFFE.TMP
   CTTFFFF.TMP
   CTT0.TMP <-- This temporary filename causes the error

RESOLUTION
==========

To avoid the error, create a file named CTT0.TMP, and place it in the directory
that the cursor library uses to generate its temporary files. Temporary files
are created in the current working directory with the 32-bit cursor library. The
cursor library will see the existing file with that name and skip over it to the
next filename (CTT1.TMP).

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This problem has been corrected in the ODBC cursor
library that ships with Visual C++ 4.0 and 4.1 (ODBCCR32.DLL, version
2.50.3006).

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

This problem applies only to the 32-bit ODBC components. However, the 16-bit MFC
programs can thunk to the 32-bit components when running on Windows NT if you've
set up a 32-bit data source rather than a 16-bit data source.

The error described in this article can appear for other reasons. Please see the
following article in the Microsoft Knowledge Base:

   Q115516 PRB: S1000: "Unable to create file buffer" ODBC Error

In general, other reasons produce a failure immediately upon trying to use the
ODBC components. The problem described in this article produces a failure after
a long period of successful operation. For example, doing a large number of
requeries can cause the error.

Additional query words: 2.50 2.51 2.52 2.52a 3.00 3.10 3.20

======================================================================
Keywords          : kbDatabase kbMFC kbODBC kbVC kbbuglist kbfixlist
Technology        : kbAudDeveloper kbMFC
Version           : 1.50 1.51 1.52 1.52a | 2.00 2.10
Issue type        : kbbug
Solution Type     : kbfix

=============================================================================

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