From 75f9c7798e200bcce252622467c68ceac0f567cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mael=20Rouxel-Labb=C3=A9?=
 <mael.rouxel.labbe@geometryfactory.com>
Date: Thu, 9 May 2019 08:06:10 +0200
Subject: [PATCH] Add a forward declaration

---
 BGL/include/CGAL/boost/graph/generators.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/BGL/include/CGAL/boost/graph/generators.h b/BGL/include/CGAL/boost/graph/generators.h
index 4df1422d895..8659f68738c 100644
--- a/BGL/include/CGAL/boost/graph/generators.h
+++ b/BGL/include/CGAL/boost/graph/generators.h
@@ -43,6 +43,11 @@ typename boost::graph_traits<Graph>::face_descriptor add_face(const VertexRange&
 
 namespace internal {
 
+template <class FaceGraph>
+void swap_vertices(typename boost::graph_traits<FaceGraph>::vertex_descriptor& p,
+                   typename boost::graph_traits<FaceGraph>::vertex_descriptor& q,
+                   FaceGraph& g);
+
 template<typename InputIterator>
 typename std::iterator_traits<InputIterator>::value_type
 random_entity_in_range(InputIterator first, InputIterator beyond,