C++ DLL from VB6 (Run-time error ‘49’: Bad DLL calling convention)

[jkeller]

Could you throw a messagebox in the .NET code and see what values the two IntPtr hold?

Second, try:

Public Sub LoadFromFile(ByVal BmpFile As String)
    Dim Template As Integer
    Dim Mask As Integer
    Call SomeFunction (BmpFile, VarPtr(Template), VarPtr(Mask), Width, Height)
End Sub

Try that with both Template and Mask as Integers and as Longs.

I did display the IntPtr values in the .NET version when I was coding that; they were indeed big negative numbers (memory addresses) which eventually dereferenced fine using the Marhal calls.

The VarPtr looks interesting. I tried it using your syntax, and this slightly modified version:

Call SomeFunction (BmpFile, VarPtr(TemplatePtr), VarPtr(MaskPtr), VarPtr(WidthPtr), VarPtr(HeightPtr))

I still get the '49' error for both calls.

I'll research VarPtr and see if I can learn more about it though; it does sound promising, thanks.