Microsoft KB Archive/171837
Article ID: 171837
Article Last Modified on 12/10/2003
- Microsoft Visual Basic 5.0 Control Creation Edition
- Microsoft Visual Basic 5.0 Learning Edition
- Microsoft Visual Basic 5.0 Professional Edition
- Microsoft Visual Basic 5.0 Enterprise Edition
This article was previously published under Q171837
The following error may occur when the if expression uses Byte data type:
Visual Basic does not evaluate Byte data type correctly in the if expression when compiled to Native code with optimizations.
Install Visual Studio 97 Service Pack 2 (SP2). The problem can also be addressed by compiling to P-code, compiling to Native Code with no optimizations, or using a data type other than the byte data type in the if expression.
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:
170365 : 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:
171554 : INFO: Visual Basic 5.0 Fixes in Visual Studio 97 Service Pack 2
The following code (known as the "Triangle Inequality") will run as expected in the Visual Basic IDE or compiled as P-code but will fail when compiled as a Native EXE file with optimizations.
Steps to Reproduce Behavior
- Start a New Standard EXE project. Form1 is created by default.
In the General Declarations section of Form1, place the following code:
Sub Checksides (a as Byte, b as Byte, c as Byte) If (c > a + b) or (a > b + c) or (b > a + c) then MsgBox "Not a triangle" Else MsgBox "Triangle" End If End Sub
In the Form_Load() event of Form1, place the following code:
Private Sub Form_Load() CheckSides 1,1,1 End End sub
- Select Project Properties from the Project menu. Open the Compile tab and make sure the project is set to compile to Native Code with some sort of optimization selected, such as Optimize for fast code.
- Select Make Project1.exe from the File Menu.
- Execute the Project1.exe file.
This will produce the error message "Run-time error 6. OverFlow."
Keywords: kbbug kbfix kbvbp500sp2fix kbvs97sp2fix KB171837