diff --git a/Arrangement_on_surface_2/include/CGAL/Curved_kernel_via_analysis_2/Point_2.h b/Arrangement_on_surface_2/include/CGAL/Curved_kernel_via_analysis_2/Point_2.h
index 2d194eb5254..789f24b841e 100644
--- a/Arrangement_on_surface_2/include/CGAL/Curved_kernel_via_analysis_2/Point_2.h
+++ b/Arrangement_on_surface_2/include/CGAL/Curved_kernel_via_analysis_2/Point_2.h
@@ -700,13 +700,13 @@ public:
         default:
           // ASCII
           os << "Point_2(";
-          os << oformat(this->ptr()->_m_xy);
+          os << ::CGAL::IO::oformat(this->ptr()->_m_xy);
           os << ",";
-          os << oformat(this->ptr()->_m_x);
+          os << ::CGAL::IO::oformat(this->ptr()->_m_x);
           os << ",";
-          os << oformat(this->ptr()->_m_curve);
+          os << ::CGAL::IO::oformat(this->ptr()->_m_curve);
           os << ",";
-          os << oformat(this->ptr()->_m_arcno);
+          os << ::CGAL::IO::oformat(this->ptr()->_m_arcno);
           os << ",";
           os << this->ptr()->_m_location;
 
diff --git a/Arrangement_on_surface_2/test/Arrangement_on_surface_2/Traits_base_test.h b/Arrangement_on_surface_2/test/Arrangement_on_surface_2/Traits_base_test.h
index 696c03ebb69..f03b66bb81d 100644
--- a/Arrangement_on_surface_2/test/Arrangement_on_surface_2/Traits_base_test.h
+++ b/Arrangement_on_surface_2/test/Arrangement_on_surface_2/Traits_base_test.h
@@ -136,8 +136,8 @@ protected:
     typename Traits::Equal_2 equal = this->m_geom_traits.equal_2_object();
     if (equal(exp_answer, real_answer)) return true;
 
-    std::string exp_answer_str  = boost::lexical_cast<std::string>( oformat(exp_answer) );
-    std::string real_answer_str = boost::lexical_cast<std::string>( oformat(real_answer) );
+    std::string exp_answer_str  = boost::lexical_cast<std::string>( CGAL::IO::oformat(exp_answer) );
+    std::string real_answer_str = boost::lexical_cast<std::string>( CGAL::IO::oformat(real_answer) );
     this->print_answer(exp_answer_str, real_answer_str, "x-monotone curve");
     return false;
   }