PRB: Multiple VB4 16-bit Apps Under Win95 GPF on Closing

• Professional and Enterprise Editions of Microsoft Visual Basic for Windows, 16-bit only, version 4.0

SYMPTOMS

When you run multiple Visual Basic 4.0 16-bit applications at the same time, each using the same controls, a General Protection Fault may occur when the last instance of the application is closed. This problem only occurs under Windows 95.

RESOLUTION

The resolution is to download and install OLEUPD.EXE from the Microsoft Software Library.

For additional information about this problem and its resolution, please see the following article in the Microsoft Knowledge Base. It can be found in the Windows 95 product Knowledge Base:

   ARTICLE-ID: Q139432
   TITLE     : OLE Update for Windows 95

STATUS

This behavior is by design.

MORE INFORMATION

The following Visual Basic 4.0 OCX controls are known to be affected by this problem:

   COMDLG16.OCX
   DBLIST16.OCX
   GRID16.OCX
   TABCTL16.OCX

Steps to Reproduce Problem

WARNING: You will need to reboot after reproducing the problem.

1. Start the 16-bit Edition of Visual Basic version 4.0 for Windows. Form1 is created by default.

2. Open the Loan Sample application found in the Samples\Grid directory.

3. Create an executable for the sample application, LOAN.EXE.

4. Start an instance of LOAN.EXE, placing it in the upper-left corner of the screen.

5. Start a second instance of LOAN.EXE.

6. Click the X button to close the first instance of LOAN.EXE in the upper- left corner of the screen.

7. Click the X button to close the second instance of LOAN.EXE.

8. An error dialog will be generated containing the following message and you will probably need to reboot to continue:

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

   The address information in the dialog varies, since the control could be anywhere in memory. The error dialog will often have garbage characters in the title bar.