std::shared_ptr works with pointer tracking

test.cpp

@@ -3,6 +3,7 @@
 #include <cereal/binary_archive/binary_archive.hpp>
 #include <cereal/binary_archive/string.hpp>
 #include <cereal/json_archive/json_archive.hpp>
+#include <cereal/binary_archive/shared_ptr.hpp>
 
 #include <cxxabi.h>
 #include <sstream>
@@ -135,12 +136,44 @@ int main()
 
   assert(e_in == e_out);
 
-  cereal::JSONOutputArchive json(std::cout);
+  //cereal::JSONOutputArchive json(std::cout);
 
-  std::string hello = "Hello, World!";
-  json & CEREAL_NVP(hello);
+  //std::string hello = "Hello, World!";
+  //json & CEREAL_NVP(hello);
   //json & CEREAL_NVP(e_out); <<< Need to figure out how to recurse!
-  //
+
+  {
+    std::ofstream os("ptr.txt");
+    cereal::BinaryOutputArchive archive(os);
+    std::shared_ptr<int> xptr1 = std::make_shared<int>(5);
+    std::shared_ptr<int> xptr2 = xptr1;
+    std::shared_ptr<int> yptr1 = std::make_shared<int>(6);
+    std::shared_ptr<int> yptr2 = yptr1;
+    archive & xptr1;
+    archive & xptr2;
+    archive & yptr1;
+    archive & yptr2;
+
+  }
+  {
+    std::ifstream is("ptr.txt");
+    cereal::BinaryInputArchive archive(is);
+    std::shared_ptr<int> xptr1;
+    std::shared_ptr<int> xptr2;
+    std::shared_ptr<int> yptr1;
+    std::shared_ptr<int> yptr2;
+    archive & xptr1;
+    archive & xptr2;
+    archive & yptr1;
+    archive & yptr2;
+
+    assert(xptr1.get() == xptr2.get());
+    assert(yptr1.get() == yptr2.get());
+    std::cout << *xptr1 << " " << *xptr2 << std::endl;
+    std::cout << *yptr1 << " " << *yptr2 << std::endl;
+  }
+
+
 
   return 0;
 }