diff --git a/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_bounded_square_2.h b/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_bounded_square_2.h
index ad9d1781b7a..c705086acfe 100644
--- a/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_bounded_square_2.h
+++ b/Segment_Delaunay_graph_Linf_2/include/CGAL/Side_of_bounded_square_2.h
@@ -246,7 +246,7 @@ namespace CGAL {
         Point_2 const *s1;
         Point_2 const *s2;
 
-        Point_2 const *dx;
+        Point_2 const *dx = NULL;
         // check if two points have the same x coordinate
         bool exist_two_with_same_x (false);
         if (samex_pq) {