diff --git a/include/expr.cpp b/include/expr.cpp
index 9a240f112..9b3470067 100755
--- a/include/expr.cpp
+++ b/include/expr.cpp
@@ -194,7 +194,7 @@ TExpression::operator const char*()
 void TExpression::print_on(ostream& out) const       
 { out << _original; }
 
-void TExpression::evaluate_user_func(const char * name, int nparms, TStack & stack) const
+void TExpression::evaluate_user_func(const char * name, int nparms, TStack & stack, TTypeexp  type) const
 
 {                
   NFCHECK("Unknown function : %s ", name);
@@ -447,7 +447,7 @@ void TExpression::eval()
       {
         const int nparms = (int) ((real &) evalstack.pop()).integer();
         
-        evaluate_user_func(instr.string(), nparms, evalstack);
+        evaluate_user_func(instr.string(), nparms, evalstack, type);
       }
       break;
     case _sqrt:
diff --git a/include/expr.h b/include/expr.h
index cce4806d2..f3c8a7dbb 100755
--- a/include/expr.h
+++ b/include/expr.h
@@ -416,7 +416,7 @@ protected:
 protected: // TObject
   // @cmember Stampa l'espressione su <p out> (serve per implementare l'insertore)
   virtual void print_on(ostream& out) const ;
-  virtual void evaluate_user_func(const char * name, int nparms, TStack & stack) const ;
+  virtual void evaluate_user_func(const char * name, int nparms, TStack & stack, TTypeexp type) const ;
 
   // @access Public Member
 public: