diff --git a/src/Mod/Fem/App/FemConstraint.cpp b/src/Mod/Fem/App/FemConstraint.cpp
index 32c8bcd26..a8f4d955b 100644
--- a/src/Mod/Fem/App/FemConstraint.cpp
+++ b/src/Mod/Fem/App/FemConstraint.cpp
@@ -58,6 +58,11 @@
 
 using namespace Fem;
 
+// maybe in the c++ standard later, older compiler don't have round()
+double round(double r) {
+    return (r > 0.0) ? floor(r + 0.5) : ceil(r - 0.5);
+}
+
 PROPERTY_SOURCE(Fem::Constraint, App::DocumentObject);
 
 Constraint::Constraint()
diff --git a/src/Mod/Fem/Gui/TaskFemConstraint.h b/src/Mod/Fem/Gui/TaskFemConstraint.h
index 72390e113..f163f6da7 100644
--- a/src/Mod/Fem/Gui/TaskFemConstraint.h
+++ b/src/Mod/Fem/Gui/TaskFemConstraint.h
@@ -40,7 +40,7 @@ public:
     TaskFemConstraint(ViewProviderFemConstraint *ConstraintView,QWidget *parent = 0,const char* pixmapname = "");
     virtual ~TaskFemConstraint() {}
 
-    virtual const std::string getReferences(void) const {}
+    virtual const std::string getReferences(void) const {return std::string();}
     const std::string getReferences(const std::vector<std::string>& items) const;
 
 protected Q_SLOTS: