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Q142397: BUG: REPLACE with UDF May Cause "Record Is Not Locked" Error

Article: Q142397
Product(s): Microsoft FoxPro
Version(s): WINDOWS:3.0,3.0b,5.0,5.0a,6.0
Operating System(s): 
Keyword(s): kbprogramming kbvfp kbvfp300bBUG kbvfp500aBUG kbvfp500bugkbbuglist
Last Modified: 10-FEB-2000

-------------------------------------------------------------------------------
The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a, 6.0 
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SYMPTOMS
========

Using a user-defined function (UDF) that moves the record pointer in the
currently selected table with a REPLACE command causes a "Record is not locked"
error message. This error occurs if the buffering property is set to
2-Pessimistic record, 3-Optimistic record, or 5-Optimistic table.

WORKAROUND
==========

Set the buffering property to 4-Pessimistic table. This locks the record and
updates it after issuing the TABLEUPDATE() function.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products listed at
the beginning of this article. We are researching this problem and will post new
information here in the Microsoft Knowledge Base as it becomes available.

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

Steps to Reproduce Problem
--------------------------

1. Create a program called Test.prg containing the following code:

     SET MULTILOCKS ON
     SET EXCLUSIVE OFF
     SET DEFAULT TO SYS(2004)+"Samples\Data"
     OPEN DATABASE Testdata
     USE Customer
     =CURSORSETPROP("Buffering",2)
     GO 5
     REPLACE maxordamt WITH mfunc()
     REPLACE maxordamt WITH mfunc()
     =TABLEUPDATE()
     =CURSORSETPROP("Buffering",1)

     FUNCTION mfunc
     ** Moves record from original position
     oldrec=IIF(EOF(),0,RECNO())
     GO 1
     tmp=maxordamt
     IF oldrec>0
        GO oldrec
     ENDIF
     RETURN tmp

2. Run the program. The error "Record is not locked" appears after encountering
  the second REPLACE command.

REFERENCES
==========

For more information about the affect of SET EXCLUSIVE, please see the following
article in the Microsoft Knowledge Base:

  Q125732 Cursor Created by User or ODBC Has EXCLUSIVE Status

For more information about the affect of READ NOLOCK, please see the following
article in the Microsoft Knowledge Base:

  Q131031 READ NOLOCK Behavior in Visual FoxPro

Additional query words: kbvfp300 kbvfp500 kbvfp600

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Keywords          : kbprogramming kbvfp kbvfp300bBUG kbvfp500aBUG kbvfp500bug kbbuglist
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b kbVFP500 kbVFP600 kbVFP500a
Version           : WINDOWS:3.0,3.0b,5.0,5.0a,6.0
Issue type        : kbbug

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

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