Q221737: FIX: C0000005 Fatal Error With SET(‘RELATION’) Function

Article: Q221737
Product(s): Microsoft FoxPro
Version(s): WINDOWS:6.0
Operating System(s): 
Keyword(s): kbservicepack kbDatabase kbvfp600 kbvfp600bug kbXBase KbDBFDBC kbVS600sp2 kbVS600SP1 kb
Last Modified: 20-MAY-1999

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, version 6.0 
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SYMPTOMS
========

When repeatedly calling the SET() function and passing the "RELATION" argument,
you might see an error similar to the the following:

  Fatal error: Exception code=C0000005
  Called from - <procedure name and line number> {<path and
  filename>}

The error may also appear as follows under Windows NT:

  An application error has occurred and an application error log is being
  generated.
  VFP6.exe
  Exception: access violation (0xc0000005),Address 0x77f6489f

It is possible that use of the SET() function with certain other arguments could
also cause this behavior. These are SET('FIELDS'), SET('ORDER'), SET('INDEX'),
SET('NOCPTRANS'), and SET('SKIP').

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.

This bug was corrected in Visual Studio 6.0 Service Pack 3. For more information
about Visual Studio service packs, please see the following articles in the
Microsoft Knowledge Base:

Q194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

Q194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed

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

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

1. Run the following code from a program (.PRG) file:

  FOR i = 1 TO 100
     @ 1,1 SAY i PICTURE '999'
     DO Proc1
  ENDFOR

  RETURN

  PROCEDURE Proc1

     DELETE FILE a01.DBF
     DELETE FILE a01.CDX
     DELETE FILE a02.DBF
     DELETE FILE a02.CDX

     CREATE TABLE a01 (f1 c(10),f2 c(10),f3 c(10),f4 c(10))
     INDEX ON f1+f2+f3+f4 TAG f1234

     CREATE TABLE a02 (f1 c(10),f2 c(10),f3 c(10),f4 c(10))
     INDEX ON f1+f2+f3+f4 TAG f1234

     SELECT a02
     SET RELATION TO ;
        SUBS(f1,1,1)+SUBS(f2,2,2)+SUBS(f3,3,3)+SUBS(f4,4,4)+;
        SUBS(f1,5,5)+SUBS(f2,6,6)+SUBS(f3,7,7)+SUBS(f4,8,8) ;
        INTO a01

     * With the following line uncommented no error occurs
     * m.setrel = SPACE(1024)

     m.setrel = SET('RELATION')

     CLOSE DATA

     RETURN
  ENDPROC

2. The error occurs.

Allocating a buffer for the variable to which the value is stored will prevent
the exception from occurring. You can remove the asterisk from the beginning of
the line m.setrel = SPACE(1024) to demonstrate this.

(c) Microsoft Corporation 1999, All Rights Reserved.
Contributions by Jim Saunders, Microsoft Corporation


Additional query words:

======================================================================
Keywords          : kbservicepack kbDatabase kbvfp600 kbvfp600bug kbXBase KbDBFDBC kbVS600sp2 kbVS600SP1 kbVS600sp3fix kbGrpDSFox 
Technology        : kbVFPsearch kbAudDeveloper kbVFP600
Version           : WINDOWS:6.0
Issue type        : kbbug
Solution Type     : kbfix

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