Declare Function GetPLCInfo Lib "user.dll" (ByVal infostr As StringBuilder, _
  ByVal _
  maxsize0 As Long) as Boolean
....
 
Dim infosstr as New StringBuilder(100)
If (LslGetPLCInfo(infostr, 100) = False) Then
    MsgBox("Error in  GetPLCInfo ")
Else
    ListBox1.Items.Add(infostr.ToString())
End If