diff --git a/Combinatorial_map/include/CGAL/Combinatorial_map_storages.h b/Combinatorial_map/include/CGAL/Combinatorial_map_storages.h
index 761c7fe1f91..cde06788e0d 100644
--- a/Combinatorial_map/include/CGAL/Combinatorial_map_storages.h
+++ b/Combinatorial_map/include/CGAL/Combinatorial_map_storages.h
@@ -64,7 +64,7 @@ namespace CGAL {
     typedef typename Dart_container::size_type             size_type;
 
     typedef std::nullptr_t Null_descriptor_type;
-    static constexpr Null_descriptor_type null_descriptor=nullptr;
+    CGAL_CPP17_INLINE static constexpr Null_descriptor_type null_descriptor=nullptr;
 
     using Type_for_compact_container=void*;
 
@@ -107,7 +107,7 @@ namespace CGAL {
     template<int i>
     using Attribute_const_handle=Attribute_const_descriptor<i>;
 
-    static constexpr Null_descriptor_type null_handle=null_descriptor;
+    CGAL_CPP17_INLINE static constexpr Null_descriptor_type null_handle=null_descriptor;
 
     /// Number of marks
     static const size_type NB_MARKS = 32;
@@ -467,6 +467,16 @@ namespace CGAL {
     typename Helper::Attribute_containers mattribute_containers;
   };
 
+#ifndef CGAL_CXX17
+  template<unsigned int d_, class Items_, class Alloc_>
+  constexpr typename Combinatorial_map_storage_1<d_, Items_, Alloc_>::Null_descriptor_type
+  Combinatorial_map_storage_1<d_, Items_, Alloc_>::null_descriptor;
+
+  template<unsigned int d_, class Items_, class Alloc_>
+  constexpr typename Combinatorial_map_storage_1<d_, Items_, Alloc_>::Null_descriptor_type
+  Combinatorial_map_storage_1<d_, Items_, Alloc_>::null_handle;
+#endif
+
 } // namespace CGAL
 
 #if defined(BOOST_GCC)
diff --git a/Generalized_map/include/CGAL/Generalized_map_storages.h b/Generalized_map/include/CGAL/Generalized_map_storages.h
index d8200128efc..d628b153a5e 100644
--- a/Generalized_map/include/CGAL/Generalized_map_storages.h
+++ b/Generalized_map/include/CGAL/Generalized_map_storages.h
@@ -64,7 +64,7 @@ namespace CGAL {
     typedef typename Dart_container::size_type            size_type;
 
     typedef std::nullptr_t Null_descriptor_type;
-    static constexpr Null_descriptor_type null_descriptor=nullptr;
+    CGAL_CPP17_INLINE static constexpr Null_descriptor_type null_descriptor=nullptr;
 
     using Type_for_compact_container=void*;
 
@@ -107,7 +107,7 @@ namespace CGAL {
     template<int i>
     using Attribute_const_handle=Attribute_const_descriptor<i>;
 
-    static constexpr Null_descriptor_type null_handle=null_descriptor;
+    CGAL_CPP17_INLINE static constexpr Null_descriptor_type null_handle=null_descriptor;
 
     /// Number of marks
     static const size_type NB_MARKS = 32;
@@ -458,6 +458,16 @@ namespace CGAL {
     typename Helper::Attribute_containers mattribute_containers;
   };
 
+#ifndef CGAL_CXX17
+  template<unsigned int d_, class Items_, class Alloc_>
+  constexpr typename Generalized_map_storage_1<d_, Items_, Alloc_>::Null_descriptor_type
+  Generalized_map_storage_1<d_, Items_, Alloc_>::null_descriptor;
+
+  template<unsigned int d_, class Items_, class Alloc_>
+  constexpr typename Generalized_map_storage_1<d_, Items_, Alloc_>::Null_descriptor_type
+  Generalized_map_storage_1<d_, Items_, Alloc_>::null_handle;
+#endif
+
 } // namespace CGAL
 
 #if defined(BOOST_GCC)
diff --git a/Linear_cell_complex/include/CGAL/CMap_linear_cell_complex_storages.h b/Linear_cell_complex/include/CGAL/CMap_linear_cell_complex_storages.h
index bb02bb50a21..661702105e1 100644
--- a/Linear_cell_complex/include/CGAL/CMap_linear_cell_complex_storages.h
+++ b/Linear_cell_complex/include/CGAL/CMap_linear_cell_complex_storages.h
@@ -74,7 +74,7 @@ namespace CGAL {
     typedef typename Dart_container::size_type             size_type;
 
     typedef std::nullptr_t Null_descriptor_type;
-    static constexpr Null_descriptor_type null_descriptor=nullptr;
+    CGAL_CPP17_INLINE static constexpr Null_descriptor_type null_descriptor=nullptr;
 
     using Type_for_compact_container=void*;
 
@@ -128,7 +128,7 @@ namespace CGAL {
     using Vertex_attribute_handle=Vertex_attribute_descriptor;
     using Vertex_attribute_const_handle=Vertex_attribute_const_descriptor;
 
-    static constexpr Null_descriptor_type null_handle=null_descriptor;
+    CGAL_CPP17_INLINE static constexpr Null_descriptor_type null_handle=null_descriptor;
 
     /// Number of marks
     static const size_type NB_MARKS = 32;
@@ -502,6 +502,17 @@ namespace CGAL {
     typename Helper::Attribute_containers mattribute_containers;
   };
 
+#ifndef CGAL_CXX17
+  template<unsigned int d_, unsigned int ambient_dim,
+           class Traits_, class Items_, class Alloc_>
+  constexpr typename CMap_linear_cell_complex_storage_1<d_,ambient_dim, Traits_, Items_, Alloc_>::Null_descriptor_type
+    CMap_linear_cell_complex_storage_1<d_,ambient_dim, Traits_, Items_, Alloc_>::null_descriptor;
+
+  template<unsigned int d_, unsigned int ambient_dim,
+           class Traits_, class Items_, class Alloc_>
+  constexpr typename CMap_linear_cell_complex_storage_1<d_,ambient_dim, Traits_, Items_, Alloc_>::Null_descriptor_type
+    CMap_linear_cell_complex_storage_1<d_,ambient_dim, Traits_, Items_, Alloc_>::null_handle;
+#endif
 } // namespace CGAL
 
 #if defined(BOOST_GCC)
diff --git a/Linear_cell_complex/include/CGAL/GMap_linear_cell_complex_storages.h b/Linear_cell_complex/include/CGAL/GMap_linear_cell_complex_storages.h
index d3d17b3cea4..6e7e03b86dd 100644
--- a/Linear_cell_complex/include/CGAL/GMap_linear_cell_complex_storages.h
+++ b/Linear_cell_complex/include/CGAL/GMap_linear_cell_complex_storages.h
@@ -74,7 +74,7 @@ namespace CGAL {
     typedef typename Dart_container::size_type             size_type;
 
     typedef std::nullptr_t Null_descriptor_type;
-    static constexpr Null_descriptor_type null_descriptor=nullptr;
+    CGAL_CPP17_INLINE static constexpr Null_descriptor_type null_descriptor=nullptr;
 
     using Type_for_compact_container=void*;
 
@@ -128,7 +128,7 @@ namespace CGAL {
     using Vertex_attribute_handle=Vertex_attribute_descriptor;
     using Vertex_attribute_const_handle=Vertex_attribute_const_descriptor;
 
-    static constexpr Null_descriptor_type null_handle=null_descriptor;
+    CGAL_CPP17_INLINE static constexpr Null_descriptor_type null_handle=null_descriptor;
 
     /// Number of marks
     static const size_type NB_MARKS = 32;
@@ -493,6 +493,18 @@ namespace CGAL {
     typename Helper::Attribute_containers mattribute_containers;
   };
 
+#ifndef CGAL_CXX17
+  template<unsigned int d_, unsigned int ambient_dim,
+           class Traits_, class Items_, class Alloc_>
+  constexpr typename GMap_linear_cell_complex_storage_1<d_, ambient_dim, Traits_, Items_, Alloc_>::Null_descriptor_type
+  GMap_linear_cell_complex_storage_1<d_, ambient_dim, Traits_, Items_, Alloc_>::null_descriptor;
+
+  template<unsigned int d_, unsigned int ambient_dim,
+           class Traits_, class Items_, class Alloc_>
+  constexpr typename GMap_linear_cell_complex_storage_1<d_, ambient_dim, Traits_, Items_, Alloc_>::Null_descriptor_type
+  GMap_linear_cell_complex_storage_1<d_, ambient_dim, Traits_, Items_, Alloc_>::null_handle;
+#endif
+
 } // namespace CGAL
 
 #if defined(BOOST_GCC)