diff --git a/erb/v1/cpp03_zone.hpp.erb b/erb/v1/cpp03_zone.hpp.erb
index 10ab7cc6..5321be7c 100644
--- a/erb/v1/cpp03_zone.hpp.erb
+++ b/erb/v1/cpp03_zone.hpp.erb
@@ -45,7 +45,7 @@ class zone {
 
         void clear() {
             finalizer* fin = m_head;
-            finalizer* tmp = nullptr;
+            finalizer* tmp = MSGPACK_NULLPTR;
             while(fin) {
                 (*fin)();
                 tmp = fin;
diff --git a/include/msgpack/v1/detail/cpp03_zone.hpp b/include/msgpack/v1/detail/cpp03_zone.hpp
index 2de4707d..f2bd7e9f 100644
--- a/include/msgpack/v1/detail/cpp03_zone.hpp
+++ b/include/msgpack/v1/detail/cpp03_zone.hpp
@@ -45,7 +45,7 @@ class zone {
 
         void clear() {
             finalizer* fin = m_head;
-            finalizer* tmp = nullptr;
+            finalizer* tmp = MSGPACK_NULLPTR;
             while(fin) {
                 (*fin)();
                 tmp = fin;
diff --git a/include/msgpack/v1/detail/cpp11_zone.hpp b/include/msgpack/v1/detail/cpp11_zone.hpp
index 7754d6e0..adca3311 100644
--- a/include/msgpack/v1/detail/cpp11_zone.hpp
+++ b/include/msgpack/v1/detail/cpp11_zone.hpp
@@ -45,7 +45,7 @@ private:
 
         void clear() {
             finalizer* fin = m_head;
-            finalizer* tmp = nullptr;
+            finalizer* tmp = MSGPACK_NULLPTR;
             while(fin) {
                 (*fin)();
                 tmp = fin;