diff --git a/sample/testHDF5.cpp b/sample/testHDF5.cpp
index f09147d..4011889 100644
--- a/sample/testHDF5.cpp
+++ b/sample/testHDF5.cpp
@@ -45,17 +45,30 @@ struct MyStruct
   char c;
 };
 
+struct MyStruct2
+{
+   MyStruct base;
+   int d;
+};
+
+
 CTOOL_STRUCT_TYPE(MyStruct, hdf5t_MyStruct,
     ((int, a))
     ((double, b))
     ((char, c))
 )
 
+CTOOL_STRUCT_TYPE(MyStruct2, hdf5t_MyStruct2,
+    ((MyStruct, base))
+    ((int, d))
+)
+
 int main()
 {
   typedef  boost::multi_array<float, 2> array_type;
   typedef  boost::multi_array<float, 3> array3_type;
   typedef  boost::multi_array<MyStruct, 1> array_mys_type;
+  typedef  boost::multi_array<MyStruct2, 1> array_mys2_type;
   typedef  boost::multi_array<std::complex<double>, 2> arrayc_type;
   typedef array_type::index index;
 
@@ -68,6 +81,7 @@ int main()
   array3_type C(boost::extents[2][3][4]);
   arrayc_type D, E;
   array_mys_type F(boost::extents[10]), G;
+  array_mys2_type H(boost::extents[10]);
   
   int values = 0;
   for (index i = 0; i != 2; i++)
@@ -79,11 +93,14 @@ int main()
         F[i].a = i;
         F[i].b = double(i)/4.;
         F[i].c = 'r'+i;
+        H[i].base = F[i];
+        H[i].d = 2*i;
     } 
   std::cout << " c = " << ((char *)&F[1])[offsetof(MyStruct, c)] << endl;
     
   CosmoTool::hdf5_write_array(g, "test_data", A);
   CosmoTool::hdf5_write_array(g, "test_struct", F);
+  CosmoTool::hdf5_write_array(g, "test_struct2", H);
   
   CosmoTool::hdf5_read_array(g, "test_data", B);