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Q176481: FIX: LUPDATE() Does Not Report Correct Century for Year 2000

Article: Q176481
Product(s): Microsoft FoxPro
Version(s): 2.01,2.1,2.6,2.6a,3.0,3.0b,5.0,5.0a
Operating System(s): 
Keyword(s): kbYear2000 kbHWMAC kbOSUNIX kbvfp
Last Modified: 14-AUG-2001

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The information in this article applies to:

- Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a 
- Microsoft FoxPro for Windows, versions 2.6, 2.6a 
- Microsoft FoxPro for MS-DOS, versions 2.6, 2.6a 
- Microsoft Visual FoxPro for Macintosh, version 3.0b 
- Microsoft FoxPro for UNIX, version 2.6 
- Microsoft FoxBASE+ for MS-DOS, version 2.1 
- Microsoft FoxBASE+ for Macintosh, version 2.01 
- Microsoft FoxPro for Macintosh, version 2.6a 
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SYMPTOMS
========

When you use SET CENTURY ON with a computer that has the system date set to the
year 2000 and a modification is made to the structure of a table (.dbf) file, or
a copy of the table file is made, the LUPDATE() function incorrectly displays
the century as 1900.

CAUSE
=====

The date of the last update is stored in the header of the .dbf file. The
LUPDATE() function reads the date of last update from the header of the .dbf
file. This problem is caused by the manner in which FoxPro writes the date into
the table's file header.

RESOLUTION
==========

Use one of the following workarounds:

- Use the FDATE() function to obtain the correct date. With SET CENTURY ON,
  this function returns the correct year.

- Create a program subroutine with the ADIR() function to obtain the file date
  parameter as illustrated by the following program code:

  SET CENTURY ON
        =ADIR(afileinfo, "CUSTOMER.DBF")
        x = afileinfo(1, 3)
        ? x

NOTE: Because FoxBase does not support either the FDATE() or ADIR() function,
these workarounds do not apply to FoxBase.


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 FoxPro 6.0.

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

The LUPDATE() function returns the date of the last update to the table in the
currently selected work area or in a specified work area. The "last updated"
date and time are not updated by the operating system until the file is closed.
When you close a modified table, FoxPro writes the current system date of the
computer into the header of the table file.

With a network, there is no guarantee that all the computers have a synchronized
date and time. If the LUPDATE() function makes it appear that the table has not
been updated today and then new information is entered into the table, you could
be overwriting new data entered from a computer that has the wrong system date.

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

1. Change the computer's system date to 02/01/2000 (the specific date is not
  critical as long as the year is 2000 or higher).

2. In the FoxPro Command window, type the following without the comments:

        SET CENTURY ON
        USE <tablename>         && Name of the table.
        ?LUPDATE()              && Checks the current value of the last 
                                && updated date.
        APPEND BLANK            && Appends a blank record to the table.
        USE                     && This closes the table.
        USE <tablename>         && Open the table again.
        ?LUPDATE()              && Check the last updated date again.

  An incorrect answer is returned: 02/01/1900.

NOTE: Remember to reset your computer system date back to today's date.

REFERENCES
==========

For more information about the LUPDATE(), FDATE(), and ADIR() functions, please
see the following articles in the Microsoft Knowledge Base:

Q130165 PRB: LUPDATE() Does Not Return Date of Last Update

Q113943 New and Enhanced Commands and Functions in FoxPro Ver 2.6

Q100554 Using ADIR() Function to Obtain MS-DOS File Information

Microsoft FoxPro Help, "LUPDATE() Function"

Microsoft FoxPro Help, "FDATE() Function"

Microsoft FoxPro Help, "ADIR() Function"

(c) Microsoft Corporation 1999, All Rights Reserved.
Contributions by Perry Newton, Microsoft Corporation


Additional query words: Y2K

======================================================================
Keywords          : kbYear2000 kbHWMAC kbOSUNIX kbvfp 
Technology        : kbHWMAC kbOSMAC kbVFPsearch kbAudDeveloper kbFoxproSearch kbZNotKeyword3 kbFoxPro260aMac kbFoxPro260DOS kbFoxPro260aDOS kbFoxPro260UNIX kbFoxPro260 kbFoxPro260a kbFoxBASE201Mac kbFoxBASE210DOS kbFoxBASESearch kbVFP300bMac kbVFP300 kbVFP300b kbVFP500 kbVFP500a
Version           : :2.01,2.1,2.6,2.6a,3.0,3.0b,5.0,5.0a
Issue type        : kbbug
Solution Type     : kbfix

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

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