FIX: Compiling VB5 Applications with Large UDTs May Crash

ID: Q171557

The information in this article applies to:

Microsoft Visual Basic Control Creation, Learning, Professional, and Enterprise Editions for Windows, version 5.0

SYMPTOMS

Compiling a project in Visual Basic 5.0 or compiling a project in Visual Basic 5.0 converted from Visual Basic 4.0, may cause an error similar to the following:

"The instruction at "0x77f64d07" referenced memory at "0x0013fff8. The memory could not be read.

Click on OK to terminate the application"

Clicking OK terminates Visual Basic 5.0.

CAUSE

Doing Put/Get on large records that contain records, VBA fails when writing out the GetPut descriptor.

A common trait of the UDTs that cause the error is that these UDTs often contain arrays of other UDTs. For example:


      Type MyType
         x as integer
         y as integer
      End Type

      Type MyType2
         a as string
         b(6) as Mytype
      End Type

Other UDTs suspected of causing the error contained 15 or more elements.

RESOLUTION

The only sure workaround is to use smaller records.

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 Studio 97 Service Pack 2.

For more information on the Visual Studio 97 Service Pack 2, please see the following article in the Microsoft Knowledge Base:

Q170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why

For a list of the Visual Basic 5.0 bugs that were fixed in the Visual Studio 97 Service Pack 2, please see the following article in the Microsoft Knowledge Base:

Q171554 INFO: Visual Basic 5.0 Fixes in Visual Studio 97 Service Pack 2

MORE INFORMATION

The UDT must be very large to cause this problem. However, it is not strictly size but the types of the members as well. The exact record size limit is unknown.

Additional query words:

Keywords : kbprg kbVS97sp2fix kbvbp500sp2fix
Version : WINDOWS:5.0
Platform : WINDOWS
Issue type : kbbug