diff --git a/include/boost/serialization/singleton.hpp b/include/boost/serialization/singleton.hpp
index 0df50661..d56cc562 100644
--- a/include/boost/serialization/singleton.hpp
+++ b/include/boost/serialization/singleton.hpp
@@ -81,29 +81,29 @@ namespace serialization {
 // attempt to retieve a mutable instances while locked will
 // generate a assertion if compiled for debug.
 
+// note usage of BOOST_DLLEXPORT.  These functions are in danger of
+// being eliminated by the optimizer when building an application in
+// release mode. Usage of the macro is meant to signal the compiler/linker
+// to avoid dropping these functions which seem to be unreferenced.
+// This usage is not related to autolinking.
+
 class BOOST_SYMBOL_VISIBLE singleton_module :
     public boost::noncopyable
 {
 private:
     BOOST_SERIALIZATION_DECL static bool & get_lock();
 public:
-    static void lock(){
+    BOOST_DLLEXPORT static void lock(){
         get_lock() = true;
     }
-    static void unlock(){
+    BOOST_DLLEXPORT static void unlock(){
         get_lock() = false;
     }
-    static bool is_locked(){
+    BOOST_DLLEXPORT static bool is_locked(){
         return get_lock();
     }
 };
 
-// note usage of BOOST_DLLEXPORT.  These functions are in danger of
-// being eliminated by the optimizer when building an application in
-// release mode. Usage of the macro is meant to signal the compiler/linker
-// to avoid dropping these functions which seem to be unreferenced.
-// This usage is not related to autolinking.
-
 template <class T>
 class singleton : public singleton_module
 {
diff --git a/test/test_optional.cpp b/test/test_optional.cpp
index 7eb7ee50..6592cdb5 100644
--- a/test/test_optional.cpp
+++ b/test/test_optional.cpp
@@ -29,10 +29,18 @@ namespace std{
 struct A {
     int m_x;
     template<class Archive>
-    void serialize(Archive & ar, const unsigned int version){};
+    void serialize(Archive & ar, const unsigned int /* version */){
+        ar & boost::serialization::make_nvp("x", m_x);
+    };
     bool operator==(const A & rhs) const {
         return m_x == rhs.m_x;
     }
+    A() :
+        m_x(0)
+    {}
+    A(int x) :
+        m_x(x)
+    {}
 };
 
 int test_main( int /* argc */, char* /* argv */[] )
@@ -43,7 +51,7 @@ int test_main( int /* argc */, char* /* argv */[] )
     const boost::optional<int> aoptional1;
     const boost::optional<int> aoptional2(123);
     const boost::optional<A> aoptional3;
-    A a;
+    A a(1);
     const boost::optional<A> aoptional4(a);
     const boost::optional<A *> aoptional5;
     const boost::optional<A *> aoptional6(& a);