#include "stdafx.h"
#include <windows.h>
#include <comdef.h>
#include <stdio.h>
 
BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
					 )
{
    return TRUE;
}
 
void __stdcall G_OpenFF(ULONG Number, PULONG pDeviceHandle) 
{ 
	*pDeviceHandle = Number;
}

    <Runtime.InteropServices.DllImport("...pfad zur dll...")> _
    Public Shared Function G_OpenFF(ByVal a As Int32, ByRef b As Int32) As _
    String
    End Function
 
    Private Sub TestDll()
        Dim i1 As Integer = 33
        Dim i2 As Integer = 44
        G_OpenFF(i1, i2)
        ' i2 = 33 jetzt
    End Sub

Those people who think they know everything are a great annoyance to those of us who do - Isaac Asimov