Why Does it not work?

Greetings,

I try to move a function which exist in my VB project over to a ATL project.

In VB my Function looks like

VB Code:

Public Function gstrCreateBarName(ByVal vstrPrivate As String, _
                                    ByVal vstrFirma As String) As String
                                    
    If vstrFirma <> gvDUMMY_EINTRAG Then
        gstrCreateBarName = vstrPrivate & " ( " & vstrFirma & ")"
    Else
        gstrCreateBarName = vstrPrivate
    End If
 
End Function

I tried the following approach in C++ but it will not work

VB Code:

STDMETHODIMP CTools::MakeBarName(BSTR Gast, BSTR Firma, BSTR *BarName)
{
    // TODO: Add your implementation code here
    bstr_t bstrFirma = Firma;
    bstr_t bstrGast = Gast;
    if (BSTR(bstrFirma) != BSTR("-/-"))
    {
        BarName = "Gast + Firma";
    }
    else
    {
        BarName = "Gast";
    }
    return S_OK;
}

any idea how I can the VB Function get over to C++

Many thanks in advance