diff --git a/example/cpp03/class_intrusive.cpp b/example/cpp03/class_intrusive.cpp
index e547ecb0..a770d734 100644
--- a/example/cpp03/class_intrusive.cpp
+++ b/example/cpp03/class_intrusive.cpp
@@ -21,10 +21,10 @@
 #include <sstream>
 #include <cassert>
 
-#if 0 // When you want to adapt map instead of array, you can enable these macro definition.
-#define MSGPACK_USE_DEFINE_MAP
-#define MSGPACK_USE_BOOST
-#endif
+// When you want to adapt map instead of array, you can enable these macro definition.
+//
+// #define MSGPACK_USE_DEFINE_MAP
+
 
 #include <msgpack.hpp>
 
@@ -100,6 +100,7 @@ int main() {
     }
     {   // create object with zone
         my_class my("John Smith", 42);
+        my.a = 123;
         my.set_b("ABC");
         my.set_c("DEF");
         msgpack::zone z;
diff --git a/example/cpp03/class_intrusive_map.cpp b/example/cpp03/class_intrusive_map.cpp
index 5b5fef33..e3ddc707 100644
--- a/example/cpp03/class_intrusive_map.cpp
+++ b/example/cpp03/class_intrusive_map.cpp
@@ -28,6 +28,9 @@ class my_class {
 public:
     my_class() {} // When you want to convert from msgpack::object to my_class,
                   // my_class should be default constractible.
+                  // If you use C++11, you can adapt non-default constructible
+                  // classes to msgpack::object.
+                  // See https://github.com/msgpack/msgpack-c/wiki/v1_1_cpp_adaptor#non-default-constructible-class-support-c11-only
     my_class(std::string const& name, int age):name_(name), age_(age) {}
 
     friend bool operator==(my_class const& lhs, my_class const& rhs) {
@@ -39,7 +42,7 @@ private:
     int age_;
 
 public:
-    MSGPACK_DEFINE(name_, age_);
+    MSGPACK_DEFINE_MAP(name_, age_);
 };
 
 void print(std::string const& buf) {