PRB: MVCOUNT May Cause Illegal Operation Error in VFP 5.0x (182138)


The information in this article applies to:

  • Microsoft Visual FoxPro for Windows 5.0, when used with:
    • the operating system: Microsoft Windows 95
  • Microsoft Visual FoxPro for Windows 5.0a, when used with:
    • the operating system: Microsoft Windows 95
This article was previously published under Q182138

SYMPTOMS

When you attempt to open a visual class library (.vcx) file in the Class Browser, the following error may appear:
This program performed an illegal operation and will be shutdown.
When you press the Details button, the following message appears:
VFP caused an invalid page fault in module VFP.EXE at <memory address>.
This problem does not occur in Visual FoxPro 3.0b or when running Visual FoxPro 5.0x on a Windows NT 4.0 computer.

CAUSE

The value of MVCOUNT in the Config.fpw file is greater than 34000.

RESOLUTION

Set MVCOUNT to a number less than 34000.

STATUS

Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

The MVCOUNT keyword allows you to control the number of variables that Visual FoxPro can use.

Steps to Reproduce Behavior

  1. Install Visual FoxPro (VFP) 5.0x on a Windows 95 computer.
  2. Add the following to the Config.fpw file: 
          MVCOUNT=65000
    Save the file and restart Visual FoxPro so it can read the new Config.fpw file.

    You can use any number greater than 34000.
  3. From the Tools menu, click Class Browser.
  4. After the Class Browser opens, attempt to open a .vcx file.

REFERENCES

Visual FoxPro Help; search on: "MVCOUNT"
Modification Type:MajorLast Reviewed:12/8/2000
Keywords:kbprb KB182138
©2002 Microsoft Corporation. All rights reserved.