[2005] Interface with C++

[campster]

I'm trying to interface with a C++ app. I have everyone tlking to each other but the data that I am sending from VB seems to be byval versus byref.

From the ProbeValue_click event I am calling the C++ interface with sVal = 1.5. I can step through the code and see the 1.5 value when I reach the C++ function. I can also watch the value change to 3.444 in the C++ code.

The intent is to call byRef so the the value in VB equals the value set by C++. The ^ character in C++ (VS8) is the same as the old C/C++ reference character *. So, from what i can tell C++ is expecting a reference but VB is send a value.

What am I missing?

Private Sub BtnProbeValue_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtnProbeValue.Click
    Dim sVar, sVal, sError As String
    Dim sts As Integer
 
    sVar = "Hoppy"
    sVal = 1.5
    sts = SimIFace.ProbeGetValue(sVar, sVal, sError)
 
  End Sub

int SimIFaceNET::ProbeGetValue(String^ sVar, String^ sVal, String^ sError)
{
  sVal = "3.444";
  sError = sError->Empty;
  return -1;
}