From ae8bf9fa9c0c0baf275d68538804be6ac6f7922a Mon Sep 17 00:00:00 2001
From: Brandon Kohn <blkohn@hotmail.com>
Date: Sun, 2 Feb 2014 13:58:57 -0500
Subject: [PATCH] Changes to singleton to allow extern templates on singletons.

---
 include/boost/serialization/extern.hpp    | 62 +++++++++++++++++++++++++++++++
 include/boost/serialization/singleton.hpp | 16 ++++----
 2 files changed, 70 insertions(+), 8 deletions(-)
 create mode 100644 include/boost/serialization/extern.hpp

diff --git a/include/boost/serialization/extern.hpp b/include/boost/serialization/extern.hpp
new file mode 100644
index 0000000..8b2cc35
--- /dev/null
+++ b/include/boost/serialization/extern.hpp
@@ -0,0 +1,62 @@
+/////////1/////////2/////////3/////////4/////////5/////////6/////////7/////////8
+// extern.hpp
+
+// (C) Copyright 2014 Brandon Kohn
+// Use, modification and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_SERIALIZATION_EXTERN_HPP
+#define BOOST_SERIALIZATION_EXTERN_HPP
+
+// MS compatible compilers support #pragma once
+#if defined(_MSC_VER)
+# pragma once
+#endif
+
+#include <boost/config.hpp>
+
+#ifndef BOOST_NO_CXX11_EXTERN_TEMPLATE
+    #define BOOST_SERIALIZATION_EXTERN_OSERIALIZER(Archive, T, Export) \
+    namespace boost { namespace serialization {                        \
+        extern template class Export singleton                         \
+        <                                                              \
+            ::boost::archive::detail::oserializer<Archive, T>          \
+        >;                                                             \
+    }}                                                                 \
+    /***/
+
+    #define BOOST_SERIALIZATION_INSTANTIATE_OSERIALIZER(Archive, T, Export) \
+    namespace boost { namespace serialization {                             \
+        template class Export singleton                                     \
+        <                                                                   \
+            ::boost::archive::detail::oserializer<Archive, T>               \
+        >;                                                                  \
+    }}                                                                      \
+    /***/
+
+    #define BOOST_SERIALIZATION_EXTERN_ISERIALIZER(Archive, T, Export) \
+    namespace boost { namespace serialization {                        \
+        extern template class Export singleton                         \
+        <                                                              \
+            ::boost::archive::detail::iserializer<Archive, T>          \
+        >;                                                             \
+    }}                                                                 \
+    /***/
+
+    #define BOOST_SERIALIZATION_INSTANTIATE_ISERIALIZER(Archive, T, Export) \
+    namespace boost { namespace serialization {                             \
+        template class Export singleton                                     \
+        <                                                                   \
+            ::boost::archive::detail::iserializer<Archive, T>               \
+        >;                                                                  \
+    }}                                                                      \
+    /***/
+#else
+    #define BOOST_SERIALIZATION_EXTERN_OSERIALIZER(Archive, T, Export)
+    #define BOOST_SERIALIZATION_INSTANTIATE_OSERIALIZER(Archive, T, Export)
+    #define BOOST_SERIALIZATION_EXTERN_ISERIALIZER(Archive, T, Export)
+    #define BOOST_SERIALIZATION_INSTANTIATE_ISERIALIZER(Archive, T, Export)    
+#endif
+
+#endif //! BOOST_SERIALIZATION_EXTERN_HPP
diff --git a/include/boost/serialization/singleton.hpp b/include/boost/serialization/singleton.hpp
index 546118c..ab6e31c 100644
--- a/include/boost/serialization/singleton.hpp
+++ b/include/boost/serialization/singleton.hpp
@@ -77,7 +77,7 @@ namespace serialization {
 // attempt to retieve a mutable instances while locked will
 // generate a assertion if compiled for debug.
 
-class singleton_module : 
+class BOOST_DLLEXPORT singleton_module : 
     public boost::noncopyable
 {
 private:
@@ -118,13 +118,13 @@ bool detail::singleton_wrapper< T >::m_is_destroyed = false;
 } // detail
 
 template <class T>
-class singleton : public singleton_module
+class BOOST_DLLEXPORT singleton : public singleton_module
 {
 private:
-    BOOST_DLLEXPORT static T & instance;
+     static T & instance;
     // include this to provoke instantiation at pre-execution time
     static void use(T const &) {}
-    BOOST_DLLEXPORT static T & get_instance() {
+     static T & get_instance() {
         static detail::singleton_wrapper< T > t;
         // refer to instance, causing it to be instantiated (and
         // initialized at startup on working compilers)
@@ -133,20 +133,20 @@ private:
         return static_cast<T &>(t);
     }
 public:
-    BOOST_DLLEXPORT static T & get_mutable_instance(){
+     static T & get_mutable_instance(){
         BOOST_ASSERT(! is_locked());
         return get_instance();
     }
-    BOOST_DLLEXPORT static const T & get_const_instance(){
+     static const T & get_const_instance(){
         return get_instance();
     }
-    BOOST_DLLEXPORT static bool is_destroyed(){
+     static bool is_destroyed(){
         return detail::singleton_wrapper< T >::m_is_destroyed;
     }
 };
 
 template<class T>
-BOOST_DLLEXPORT T & singleton< T >::instance = singleton< T >::get_instance();
+ T & singleton< T >::instance = singleton< T >::get_instance();
 
 } // namespace serialization
 } // namespace boost
-- 
1.8.5.2.msysgit.0