DOCUMENT:Q162553  24-MAR-2000  [foxpro]
TITLE   :FIX: ALEN() Function Causes Illegal Operation in Debug Window
PRODUCT :Microsoft FoxPro
PROD/VER:WINDOWS:3.0,3.0b
OPER/SYS:
KEYWORDS:kbvfp kbvfp300bBUG kbvfp500fixkbbuglist kbfixlist

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The information in this article applies to:

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

Using the ALEN() function in the Debug window to reference an array that does
not exist in a form causes Visual FoxPro 3.0 for Windows to shut down. The
following error message appears in Windows 95 after the form closes:

   This program has performed an illegal operation and will be shut down.

Clicking Details reveals the following message:

   VFP caused an invalid page fault in module <module name> at <memory
   address>.

In Windows NT 4.0, the following error appears:

   An application error has occurred and an application error log is being
   generated.

   VFP.exe
   Exception: access violation <error number>, Address: <memory
   address>.

The operating system then closes Visual FoxPro.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual FoxPro 5.0 for
Windows.

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

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

1. Create a form called ztest.scx.

2. Add a command button to the form. In the Click event of the button, place the
   following code:

         ThisForm.Release

3. Save the form.

4. Invoke the Debug window, type the following line, and press the Enter key:

   " ALEN(ThisForm.atest) " (without the quotation marks)

   This references a nonexistent array.

5. Run the form and click the command button to close the form.

6. The error occurs and Visual FoxPro shuts down.

Additional query words:

======================================================================
Keywords          : kbvfp kbvfp300bBUG kbvfp500fix kbbuglist kbfixlist
Technology        : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b
Version           : WINDOWS:3.0,3.0b
Issue type        : kbbug
Solution Type     : kbfix

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