diff --git a/src/OpenMesh/Apps/Decimating/DecimaterViewerWidget.hh b/src/OpenMesh/Apps/Decimating/DecimaterViewerWidget.hh
index 49037a2c..8b3f11e7 100644
--- a/src/OpenMesh/Apps/Decimating/DecimaterViewerWidget.hh
+++ b/src/OpenMesh/Apps/Decimating/DecimaterViewerWidget.hh
@@ -114,7 +114,7 @@ public:
   typedef Decimater::ModNormalFlippingT< mesh_t >::Handle mod_nf_t;
 
   // object types
-#if __cplusplus > 199711L or __GXX_EXPERIMENTAL_CXX0X__
+#if __cplusplus > 199711L || defined(__GXX_EXPERIMENTAL_CXX0X__)
   typedef std::unique_ptr< decimater_t   >   decimater_o;
 #else
   typedef std::auto_ptr< decimater_t   >   decimater_o;
diff --git a/src/OpenMesh/Apps/Unsupported/OsgViewer/osgviewer.cc b/src/OpenMesh/Apps/Unsupported/OsgViewer/osgviewer.cc
index 60fad933..a3c43e90 100644
--- a/src/OpenMesh/Apps/Unsupported/OsgViewer/osgviewer.cc
+++ b/src/OpenMesh/Apps/Unsupported/OsgViewer/osgviewer.cc
@@ -131,7 +131,7 @@ public:
 
   bool bind( osg::GeometryPtr geo )
   {
-    #if __cplusplus > 199711L or __GXX_EXPERIMENTAL_CXX0X__
+    #if __cplusplus > 199711L || defined(__GXX_EXPERIMENTAL_CXX0X__)
       std::unique_ptr<mesh_t> obj(new mesh_t);
     #else
       std::auto_ptr<mesh_t> obj(new mesh_t);
diff --git a/src/OpenMesh/Core/Utils/PropertyManager.hh b/src/OpenMesh/Core/Utils/PropertyManager.hh
index aec248f9..88b495b0 100644
--- a/src/OpenMesh/Core/Utils/PropertyManager.hh
+++ b/src/OpenMesh/Core/Utils/PropertyManager.hh
@@ -76,7 +76,7 @@ namespace OpenMesh {
  */
 template<typename PROPTYPE, typename MeshT>
 class PropertyManager {
-#if __cplusplus > 199711L or __GXX_EXPERIMENTAL_CXX0X__
+#if __cplusplus > 199711L || defined(__GXX_EXPERIMENTAL_CXX0X__)
     public:
         PropertyManager(const PropertyManager&) = delete;
         PropertyManager& operator=(const PropertyManager&) = delete;
@@ -148,7 +148,7 @@ class PropertyManager {
 
         MeshT &getMesh() const { return *mesh_; }
 
-#if __cplusplus > 199711L or __GXX_EXPERIMENTAL_CXX0X__
+#if __cplusplus > 199711L || defined(__GXX_EXPERIMENTAL_CXX0X__)
         /// Only for pre C++11 compatibility.
 
         typedef PropertyManager<PROPTYPE, MeshT> Proxy;
diff --git a/src/Unittests/unittests_cpp_11_features.cc b/src/Unittests/unittests_cpp_11_features.cc
index 682f11d0..935856f9 100644
--- a/src/Unittests/unittests_cpp_11_features.cc
+++ b/src/Unittests/unittests_cpp_11_features.cc
@@ -53,7 +53,7 @@ class OpenMesh_Triangle : public OpenMeshBase {
  * ====================================================================
  */
 
-#if __cplusplus > 199711L or __GXX_EXPERIMENTAL_CXX0X__
+#if __cplusplus > 199711L || defined(__GXX_EXPERIMENTAL_CXX0X__)
 
 /*
  */