Q145721: FIX: Access Violation Error on 16 MB Windows NT System

Article: Q145721
Product(s): Microsoft FoxPro
Version(s): 3.00
Operating System(s): 
Keyword(s): kbenvkbbuglist kbfixlist
Last Modified: 24-MAR-2000

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 3.0 
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SYMPTOMS
========

The "Access violation" error may occur when you use table buffering,
transactions, and large amounts of data on a computer system that has 16
megabytes of memory and that is running Windows NT version 3.51. The error does
not occur on sytems running Windows NT with 24 or 32 megabytes of RAM.

WORKAROUND
==========

Use TABLEUPDATE() with smaller data sets. The Sample Code listed in this article
fails when updating 4000 records at one time. However, reducing the number to
2000 cures the problem.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article. This problem was corrected in Visual FoxPro 3.0b
for Windows.

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

Sample Code to Reproduce Problem
--------------------------------

  *-- Begin Code Example
  SET ESCAPE OFF
  SET TALK OFF
  SET FULL ON
  SET DELETED ON
  SET EXCLUSIVE OFF
  SET EXACT ON
  SET MULTILOCKS ON

  CLOSE DATA ALL

  IF !FILE( 'mydbc.dbc' )
      CREATE DATABASE mydbc
      OPEN DATA mydbc EXCLUSIVE
      CREATE TABLE mytable (keyfld n(10) PRIMARY KEY)
      CLOSE DATA ALL
  ENDIF

  USE mytable
  CALC MAX(keyfld) TO m.keyfld

  IF CURSORSETPROP('buffering', 5 )
      ? 'table buffering enabled'

      FOR i = 1 TO 4000
          m.keyfld = m.keyfld + 1
              IF i % 100 = 0
                  ? i, ' records added'
              ENDIF
              INSERT INTO mytable (keyfld) VALUES (m.keyfld)
      ENDFOR

      ? 'beginning transaction'
      BEGIN TRANSACTION
      ? 'transaction begun'

      IF TABLEUPDATE( .t. )
              ? 'table update succeeded'
      ELSE
              ? 'table update failed'
              =TABLEREVERT(.t.)
      ENDIF

      ? 'ending transaction'
      END TRANSACTION
      ? 'transaction ended'

  ENDIF
  WAIT WINDOW
  CLOSE DATA ALL
  *-- End Code Example

NOTE: This has not been tested on computers that are running Windows for
Workgroups or Windows 95 with 16 megabytes of RAM.

Additional query words: VFoxWin buglist3.00 fixlist3.00b Crash tableupdate

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Keywords          : kbenv kbbuglist kbfixlist
Technology        : kbVFPsearch kbAudDeveloper kbVFP300
Version           : 3.00
Issue type        : kbbug
Solution Type     : kbfix

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