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Q184969: PRB: SET COMPATIBLE ON Causes Problems with Arrays

Article: Q184969
Product(s): Microsoft FoxPro
Version(s): MACINTOSH:3.0; WINDOWS:3.0,3.0b,5.0,5.0a
Operating System(s): 
Keyword(s): kbHWMAC kbvfp
Last Modified: 02-MAY-2001

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The information in this article applies to:

- MSPRESS Hardcore Visual Basic, Second Edition ISBN 1-57231-422-2, versions 3.0, 3.0b 
- Microsoft Visual FoxPro for Windows, versions 5.0, 5.0a 
- Microsoft Visual FoxPro for Macintosh, Professional Edition, version 3.0 
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SYMPTOMS
========

If SET COMPATIBLE is ON and an array is redimensioned, the array loses it
previously saved values and sets the current value to logical false (.F.).

CAUSE
=====

When SET COMPATIBLE is set to ON or DB4, Visual FoxPro overwrites any existing
array with a variable of the same name when a STORE command or assignment is
made.

RESOLUTION
==========

If the array needs to retain its contents, try one of the following:

- Issue SET COMPATIBLE OFF in the program or form.

- Add COMPATIBLE=OFF to the Config.fpw file.

- From the Tools menu, select Options. In the Options dialog box, click the
  General tab and clear the dBase compatibility check box.

STATUS
======

This behavior is by design.

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

Steps to Reproduce Behavior
---------------------------

This can be demonstrated when an array is redimensioned within a loop. To
reproduce the problem, create a new program and enter the following code:

     CLEAR
     SET COMPATIBLE ON         && Or SET COMPATIBLE DB4
     DIMENSION atest(5)     && Dimension to some value.
     FOR i = 1 to 10
        DIMENSION atest(i)
        Atest(i)="Test "+ALLTRIM(STR(i))
     ENDFOR

     DISPLAY MEMORY LIKE atest

When the code is executed, the array has 10 elements, but only the last element
contains a value. The other elements contain a logical false (.F.).
(c) Microsoft Corporation 1998, All Rights Reserved.
Contributions by Dean Christopher, Microsoft Corporation


REFERENCES
==========

Visual FoxPro 3.x for Windows Help; search on: "SET COMPATIBLE" (without the
quotation marks) and "STORE" (without the quotation marks)
Visual FoxPro 3.0b for Macintosh Help; search on: "SET COMPATIBLE" (without the
quotation marks) and "STORE" (without the quotation marks)
Visual FoxPro 5.x for Windows Help; search on: "SET COMPATIBLE" (without the
quotation marks) and "STORE" (without the quotation marks)
Visual FoxPro 3.x for Windows, "Language Reference", pages 756 and 794.
Visual FoxPro 5.x for Windows, "Language Reference", pages 379 and 403.
Visual FoxPro 3.0b for Macintosh, "Language Reference", pages 803 and 843.

Additional query words:

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Keywords          : kbHWMAC kbvfp 
Technology        : kbMSPressSearch kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbVFP300Mac kbVFP500 kbVFP500a
Version           : MACINTOSH:3.0; WINDOWS:3.0,3.0b,5.0,5.0a
Issue type        : kbprb

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