diff --git a/include/epanet2.bas b/include/epanet2.bas
index 1c1435c..321f4f3 100644
--- a/include/epanet2.bas
+++ b/include/epanet2.bas
@@ -206,7 +206,7 @@ Global Const EN_CUSTOM = 2        ' user-defined custom curve
  Declare Function ENgetlinkvalue Lib "epanet2.dll" (ByVal Index As Long, ByVal Code As Long, Value As Single) As Long
 
  Declare Function ENgetcurve Lib "epanet2.dll" (ByVal CurveIndex As Long, ByVal CurveID As String, nValues As Long, xValues As Any, yValues As Any) As Long
- Declare Function ENgetheadcurveindex Lib "epanet2.dll" (ByVal PumpIndex As Long, ByVal CurveIndex As Long) As Long
+ Declare Function ENgetheadcurveindex Lib "epanet2.dll" (ByVal PumpIndex As Long, CurveIndex As Long) As Long
  Declare Function ENgetpumptype Lib "epanet2.dll" (ByVal Index As Long, PumpType As Long) As Long
 
  Declare Function ENgetversion Lib "epanet2.dll" (Value As Long) As Long