From 81f4714b1b6d7e6384975b0a02714c8f7424e529 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sebastien.loriot@cgal.org>
Date: Thu, 29 Dec 2016 10:25:11 +0100
Subject: [PATCH] mimic what is done for Has_clear

typeof is an gcc extension
---
 .../boost/graph/split_graph_into_polylines.h  | 27 +++++++++++++------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/BGL/include/CGAL/boost/graph/split_graph_into_polylines.h b/BGL/include/CGAL/boost/graph/split_graph_into_polylines.h
index adb9552c763..7c50bb16791 100644
--- a/BGL/include/CGAL/boost/graph/split_graph_into_polylines.h
+++ b/BGL/include/CGAL/boost/graph/split_graph_into_polylines.h
@@ -39,16 +39,26 @@ struct IsTerminalDefault
   }
 };
 
-template <typename T>
-class BGL_sgip_visitor_has_add_edge {
-  typedef char yes;
-  struct no { char t[2]; };
+template<class T, class ED>
+class BGL_sgip_visitor_has_add_edge
+{
+private:
+  template<class U, U>
+  class check {};
 
-  template <typename C> static yes test( typeof(&C::add_edge) );
-  template <typename C> static no test(...);
+  template<class C>
+  static char f(check<void(C::*)(ED), &C::add_edge>*);
 
+  template<class C>
+  static char f(check<void(C::*)(const ED&), &C::add_edge>*);
+
+  template<class C>
+  static char f(check<void(C::*)(ED&), &C::add_edge>*);
+
+  template<class C>
+  static int f(...);
 public:
-  enum { value = sizeof(test<T>(0)) == sizeof(yes) };
+  static const bool value = (sizeof(f<T>(0)) == sizeof(char));
 };
 
 template <typename Visitor, typename Edge_descriptor>
@@ -57,6 +67,7 @@ bgl_sgip_maybe_call_visitor_add_edge_impl(Visitor&,
                                           Edge_descriptor,
                                           CGAL::Tag_false /*has_add_edge*/)
 {
+
 }
 
 template <typename Visitor, typename Edge_descriptor>
@@ -71,7 +82,7 @@ bgl_sgip_maybe_call_visitor_add_edge_impl(Visitor& visitor,
 template <typename Visitor, typename Edge_descriptor>
 void bgl_sgip_maybe_call_visitor_add_edge(Visitor& visitor,
                                           Edge_descriptor e) {
-  typedef BGL_sgip_visitor_has_add_edge<Visitor> Has_add_edge;
+  typedef BGL_sgip_visitor_has_add_edge<Visitor, Edge_descriptor> Has_add_edge;
   bgl_sgip_maybe_call_visitor_add_edge_impl
     ( visitor, e, CGAL::Boolean_tag<Has_add_edge::value>() );
 }