Visual Basic 5 Curiosities
All examples were tested with VB5.
Arrays with zero Items
Private Sub Command1_Click()
Dim buffer(3) As Byte
Dim arr() As Byte
arr = MidB(buffer, 1, 0)
Call MsgBox(LBound(arr) & " / " & UBound(arr))
' LBound is 0 and UBound is -1
' but ReDim arr(0 to -1) is not allowed.
Private Sub Form_Load()
Dim byteBuf(3) As Byte
Dim byteSeq() As Byte
byteSeq = byteBuf
' Is allowed
Dim longBuf(3) As Long
Dim longSeq() As Long
longSeq = longBuf
' Is not possible. Why?
Long VB names
It is not possible to compile VB programs to executable files
if project name plus class name has more than 39 characters
due to a limitation of VB5 and ActiveX.
VB knows a decimal type but you have to use Variant. CORBA long long
is mapped to a Decimal inside a Variant.
Dim decVal As Variant
decVal = CDec("12345678901234567890")
Global Err object
Each ActiveX-DLL has its own global Err object if you use the DLL by reference.
There is only one global Err object if you include the DLL project in your main
project for debugging purposes and you get different behavior.
Garbage collection of weak circular references
VB do not garbage collection of weak circular references.
A reason of some memory leaks in VB applications.
ActiveX EXE doesn´t terminate if circular references exists.
Use of `As New' is discouraged
Dim obj As New cMyClass
Set obj = Nothing
If obj Is Nothing Then
This is never happen therefore declaring variables As New is,
in general, discouraged.