From a86712d1aae9a1a6d2004db3fc8fcdac6ef6b782 Mon Sep 17 00:00:00 2001
From: Thomas Krijnen <t.krijnen@gmail.com>
Date: Sun, 7 Jun 2020 15:25:18 +0200
Subject: [PATCH] Don't segfault on empty Nef_nary_x

---
 Nef_3/include/CGAL/Nef_nary_intersection_3.h | 3 ++-
 Nef_3/include/CGAL/Nef_nary_union_3.h        | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/Nef_3/include/CGAL/Nef_nary_intersection_3.h b/Nef_3/include/CGAL/Nef_nary_intersection_3.h
index 70fc5791fae..5178705dc2f 100644
--- a/Nef_3/include/CGAL/Nef_nary_intersection_3.h
+++ b/Nef_3/include/CGAL/Nef_nary_intersection_3.h
@@ -52,7 +52,8 @@ class Nef_nary_intersection_3 {
   }
 
   Polyhedron get_intersection() {
-
+    if (queue.empty())
+      return empty;
     while(queue.size() > 1)
       intersect();
     inserted = 0;
diff --git a/Nef_3/include/CGAL/Nef_nary_union_3.h b/Nef_3/include/CGAL/Nef_nary_union_3.h
index ecbbae2db59..c8663bb911b 100644
--- a/Nef_3/include/CGAL/Nef_nary_union_3.h
+++ b/Nef_3/include/CGAL/Nef_nary_union_3.h
@@ -52,7 +52,8 @@ class Nef_nary_union_3 {
   }
 
   Polyhedron get_union() {
-
+    if (queue.empty())
+      return empty;
     while(queue.size() > 1)
       unite();
     inserted = 0;