FIX: ALEN() Function Causes Illegal Operation in Debug Window

• Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b

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.

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

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

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

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)
   

   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.