diff --git a/Packages/Matrix_search/include/CGAL/Sorted_matrix_search_traits_adaptor.h b/Packages/Matrix_search/include/CGAL/Sorted_matrix_search_traits_adaptor.h
index db6c87471ae..bef9edb640a 100644
--- a/Packages/Matrix_search/include/CGAL/Sorted_matrix_search_traits_adaptor.h
+++ b/Packages/Matrix_search/include/CGAL/Sorted_matrix_search_traits_adaptor.h
@@ -28,17 +28,17 @@
 
 CGAL_BEGIN_NAMESPACE
 
-template < class _FeasibilityTest, class _Matrix >
+template < class FeasibilityTest_, class Matrix_ >
 class Sorted_matrix_search_traits_adaptor {
 public:
-  typedef _FeasibilityTest         FeasibilityTest;
-  typedef _Matrix                  Matrix;
-  typedef typename _Matrix::Value  Value;
+  typedef FeasibilityTest_         FeasibilityTest;
+  typedef Matrix_                  Matrix;
+  typedef typename Matrix::Value   Value;
   typedef std::less< Value >       Compare_strictly;
   typedef std::less_equal< Value > Compare_non_strictly;
 
   Sorted_matrix_search_traits_adaptor(FeasibilityTest ft)
-  : _ft( ft)
+  : ft_( ft)
   {}
 
   Compare_strictly
@@ -51,10 +51,10 @@ public:
 
   bool
   is_feasible(Value a)
-  { return _ft( a); }
+  { return ft_( a); }
 
 protected:
-  FeasibilityTest _ft;
+  FeasibilityTest ft_;
 };
 
 //!!! with iterator traits we replace const Matrix&
diff --git a/Packages/Matrix_search/include/CGAL/Transform_iterator.h b/Packages/Matrix_search/include/CGAL/Transform_iterator.h
index e18f7c3e22c..7bd72421655 100644
--- a/Packages/Matrix_search/include/CGAL/Transform_iterator.h
+++ b/Packages/Matrix_search/include/CGAL/Transform_iterator.h
@@ -40,10 +40,10 @@ struct Transform_iterator {
 
   Transform_iterator( const OutputIterator& o,
                       const Operation& op)
-    : _o( o), _op( op)
+    : o_( o), op_( op)
   {}
 
-  operator OutputIterator() { return _o; }
+  operator OutputIterator() { return o_; }
 
   self& operator*() { return *this; }
 
@@ -52,13 +52,13 @@ struct Transform_iterator {
   self& operator++( int) { return *this; }
 
   self& operator=( const argument_type& a) {
-    *(_o++) = _op( a);
+    *(o_++) = op_( a);
     return *this;
   }
 
 private:
-  OutputIterator _o;
-  Operation      _op;
+  OutputIterator o_;
+  Operation      op_;
 };
 
 template < class OutputIterator, class Operation > inline
diff --git a/Packages/Matrix_search/include/CGAL/extremal_polygon_2.h b/Packages/Matrix_search/include/CGAL/extremal_polygon_2.h
index 3761dd698e1..980cdfda23e 100644
--- a/Packages/Matrix_search/include/CGAL/extremal_polygon_2.h
+++ b/Packages/Matrix_search/include/CGAL/extremal_polygon_2.h
@@ -183,7 +183,7 @@ template < class RandomAccessIC,
 template < class RandomAccessIC,
            class Outputiterator,
            class Traits,
-           class _FT >
+           class FT_ >
 #endif
 Outputiterator
 CGAL_maximum_inscribed_rooted_k_gon(
@@ -193,7 +193,7 @@ CGAL_maximum_inscribed_rooted_k_gon(
 #ifndef CGAL_CFG_MATCHING_BUG_1
   typename Traits::FT& max_area,
 #else
-  _FT& max_area,
+  FT_& max_area,
 #endif
   Outputiterator o,
   const Traits& t)
@@ -282,7 +282,7 @@ template < class RandomAccessIC_point,
            class RandomAccessIC_int,
            class OutputIterator,
            class Traits,
-           class _FT >
+           class FT_ >
 #endif
 OutputIterator
 CGAL_maximum_inscribed_rooted_k_gon(
@@ -296,7 +296,7 @@ CGAL_maximum_inscribed_rooted_k_gon(
 #ifndef CGAL_CFG_MATCHING_BUG_1
   typename Traits::FT& max_area,
 #else
-  _FT& max_area,
+  FT_& max_area,
 #endif
   OutputIterator o,
   const Traits& t)
@@ -373,7 +373,7 @@ CGAL_maximum_inscribed_rooted_k_gon(
   #ifndef CGAL_CFG_MATCHING_BUG_1
   typedef typename Traits::FT               FT;
   #else
-  typedef _FT                               FT;
+  typedef FT_                               FT;
   #endif
   typedef std::vector< FT >                 FT_cont;
   typedef std::vector< int >                Index_cont;
@@ -654,7 +654,7 @@ template < class RandomAccessIC_point,
            class RandomAccessIC_int,
            class OutputIterator,
            class Traits,
-           class _FT >
+           class FT_ >
 #endif
 OutputIterator
 CGAL_maximum_inscribed_k_gon(
@@ -670,7 +670,7 @@ CGAL_maximum_inscribed_k_gon(
 #ifndef CGAL_CFG_MATCHING_BUG_1
   typename Traits::FT& max_area,
 #else
-  _FT& max_area,
+  FT_& max_area,
 #endif
   OutputIterator o,
   const Traits& t)
@@ -710,7 +710,7 @@ CGAL_maximum_inscribed_k_gon(
 #ifndef CGAL_CFG_MATCHING_BUG_1
   typedef typename Traits::FT               FT;
 #else
-  typedef _FT                               FT;
+  typedef FT_                               FT;
 #endif
   typedef std::vector< int >        Index_cont;