diff --git a/libsrc/geom2d/csg2d.hpp b/libsrc/geom2d/csg2d.hpp
index cb77143e..eeb1a75b 100644
--- a/libsrc/geom2d/csg2d.hpp
+++ b/libsrc/geom2d/csg2d.hpp
@@ -111,7 +111,7 @@ struct Vertex : Point<2>
   optional<Spline> spline = nullopt;
   EdgeInfo info;
 
-  Vertex * Insert(Point<2> p, double lam = -1.0);
+  DLL_HEADER Vertex * Insert(Point<2> p, double lam = -1.0);
 
   void Link( Vertex * v )
   {
@@ -562,16 +562,16 @@ struct Solid2d
 
   Solid2d() = default;
   Solid2d(string name_) : name(name_) {}
-  Solid2d(const Array<std::variant<Point<2>, EdgeInfo>> & points, string name_=MAT_DEFAULT, string bc_=BC_DEFAULT);
+  DLL_HEADER Solid2d(const Array<std::variant<Point<2>, EdgeInfo>> & points, string name_=MAT_DEFAULT, string bc_=BC_DEFAULT);
 
-  Solid2d operator+(const Solid2d & other) const;
-  Solid2d operator*(const Solid2d & other) const;
-  Solid2d operator-(const Solid2d & other) const;
+  DLL_HEADER Solid2d operator+(const Solid2d & other) const;
+  DLL_HEADER Solid2d operator*(const Solid2d & other) const;
+  DLL_HEADER Solid2d operator-(const Solid2d & other) const;
 
-  Solid2d& operator=(const Solid2d & other) = default;
-  Solid2d& operator+=(const Solid2d & other);
-  Solid2d& operator*=(const Solid2d & other);
-  Solid2d& operator-=(const Solid2d & other);
+  DLL_HEADER Solid2d& operator=(const Solid2d & other) = default;
+  DLL_HEADER Solid2d& operator+=(const Solid2d & other);
+  DLL_HEADER Solid2d& operator*=(const Solid2d & other);
+  DLL_HEADER Solid2d& operator-=(const Solid2d & other);
 
   void Append( const Loop & poly )
   {
@@ -646,15 +646,15 @@ class CSG2d
       solids.Append(s);
     }
 
-    shared_ptr<netgen::SplineGeometry2d> GenerateSplineGeometry();
-    shared_ptr<netgen::Mesh> GenerateMesh(MeshingParameters & mp);
+    DLL_HEADER shared_ptr<netgen::SplineGeometry2d> GenerateSplineGeometry();
+    DLL_HEADER shared_ptr<netgen::Mesh> GenerateMesh(MeshingParameters & mp);
 };
 
-Solid2d Circle( Point<2> center, double r, string name="", string bc="");
-Solid2d Rectangle( Point<2> p0, Point<2> p1, string mat=MAT_DEFAULT, string bc=BC_DEFAULT );
+DLL_HEADER Solid2d Circle( Point<2> center, double r, string name="", string bc="");
+DLL_HEADER Solid2d Rectangle( Point<2> p0, Point<2> p1, string mat=MAT_DEFAULT, string bc=BC_DEFAULT );
 
-void AddIntersectionPoints ( Solid2d & s1, Solid2d & s2 );
-Solid2d ClipSolids ( Solid2d s1, Solid2d s2, bool intersect=true );
+DLL_HEADER void AddIntersectionPoints ( Solid2d & s1, Solid2d & s2 );
+DLL_HEADER Solid2d ClipSolids ( Solid2d s1, Solid2d s2, bool intersect=true );
 
 }
 #endif // NETGEN_CSG2D_HPP_INCLUDED
diff --git a/libsrc/geom2d/geometry2d.hpp b/libsrc/geom2d/geometry2d.hpp
index e71d17d8..daab8d12 100644
--- a/libsrc/geom2d/geometry2d.hpp
+++ b/libsrc/geom2d/geometry2d.hpp
@@ -204,8 +204,8 @@ namespace netgen
 
 
     size_t GetNDomains() const { return materials.Size(); }
-    void GetMaterial (int  domnr, char* & material );
-    void SetMaterial (int  domnr, const string & material);
+    DLL_HEADER void GetMaterial (int  domnr, char* & material );
+    DLL_HEADER void SetMaterial (int  domnr, const string & material);
 
     double GetDomainMaxh ( const int domnr );
     void SetDomainMaxh ( const int domnr, double maxh );
diff --git a/libsrc/gprim/geomtest3d.hpp b/libsrc/gprim/geomtest3d.hpp
index c1fb1186..b26c9b41 100644
--- a/libsrc/gprim/geomtest3d.hpp
+++ b/libsrc/gprim/geomtest3d.hpp
@@ -75,7 +75,7 @@ extern double MinDistLP2 (const Point2d & lp1, const Point2d & lp2, const Point2
 extern double MinDistLP2 (const Point3d & lp1, const Point3d & lp2, const Point3d & p);
 
 /// Minimal distance of point p to the triangle segment [tp1,tp2,pt3]
-extern double MinDistTP2 (const Point3d & tp1, const Point3d & tp2, 
+DLL_HEADER double MinDistTP2 (const Point3d & tp1, const Point3d & tp2, 
 			  const Point3d & tp3, const Point3d & p);
 
   inline double MinDistTP2 (const Point<2> & tp1, const Point<2> & tp2, 
diff --git a/libsrc/gprim/spline.hpp b/libsrc/gprim/spline.hpp
index b594f85b..94a96f60 100644
--- a/libsrc/gprim/spline.hpp
+++ b/libsrc/gprim/spline.hpp
@@ -200,9 +200,9 @@ namespace netgen
     double GetWeight () const { return weight; }
     void SetWeight (double w) { weight = w; }
     ///
-    virtual Point<D> GetPoint (double t) const;
+    DLL_HEADER virtual Point<D> GetPoint (double t) const;
     ///
-    virtual Vec<D> GetTangent (const double t) const;
+    DLL_HEADER virtual Vec<D> GetTangent (const double t) const;
 
   
     DLL_HEADER virtual void GetDerivatives (const double t, 
@@ -210,12 +210,12 @@ namespace netgen
 				 Vec<D> & first,
 				 Vec<D> & second) const;
     ///
-    virtual const GeomPoint<D> & StartPI () const { return p1; };
+    DLL_HEADER virtual const GeomPoint<D> & StartPI () const { return p1; };
     ///
-    virtual const GeomPoint<D> & EndPI () const { return p3; }
+    DLL_HEADER virtual const GeomPoint<D> & EndPI () const { return p3; }
     ///
-    virtual void GetCoeff (Vector & coeffs) const;
-    virtual void GetCoeff (Vector & coeffs, Point<D> p0) const;
+    DLL_HEADER virtual void GetCoeff (Vector & coeffs) const;
+    DLL_HEADER virtual void GetCoeff (Vector & coeffs, Point<D> p0) const;
     
     virtual string GetType(void) const {return "spline3";}