diff --git a/include/chaiscript/dispatchkit/exception_specification.hpp b/include/chaiscript/dispatchkit/exception_specification.hpp
index 10c3826..c0a6e3c 100644
--- a/include/chaiscript/dispatchkit/exception_specification.hpp
+++ b/include/chaiscript/dispatchkit/exception_specification.hpp
@@ -17,6 +17,8 @@ namespace chaiscript
     {
       virtual void handle(const Boxed_Value &bv, const Dispatch_Engine &t_engine) = 0;
 
+      virtual ~Exception_Handler_Base() {}
+
       protected:
         template<typename T>
         void throw_type(const Boxed_Value &bv, const Dispatch_Engine &t_engine)
@@ -28,6 +30,8 @@ namespace chaiscript
     template<typename T1>
       struct Exception_Handler_Impl1 : Exception_Handler_Base
       {
+        virtual ~Exception_Handler_Impl1() {}
+
         virtual void handle(const Boxed_Value &bv, const Dispatch_Engine &t_engine)
         {
           throw_type<T1>(bv, t_engine);
@@ -36,6 +40,8 @@ namespace chaiscript
     template<typename T1, typename T2>
       struct Exception_Handler_Impl2 : Exception_Handler_Base
       {
+        virtual ~Exception_Handler_Impl2() {}
+
         virtual void handle(const Boxed_Value &bv, const Dispatch_Engine &t_engine)
         {
           throw_type<T1>(bv, t_engine);
@@ -46,6 +52,8 @@ namespace chaiscript
     template<typename T1, typename T2, typename T3>
       struct Exception_Handler_Impl3 : Exception_Handler_Base
       {
+        virtual ~Exception_Handler_Impl3() {}
+
         virtual void handle(const Boxed_Value &bv, const Dispatch_Engine &t_engine)
         {
           throw_type<T1>(bv, t_engine);
@@ -56,6 +64,8 @@ namespace chaiscript
     template<typename T1, typename T2, typename T3, typename T4>
       struct Exception_Handler_Impl4 : Exception_Handler_Base
       {
+        virtual ~Exception_Handler_Impl4() {}
+
         virtual void handle(const Boxed_Value &bv, const Dispatch_Engine &t_engine)
         {
           throw_type<T1>(bv, t_engine);
@@ -67,6 +77,8 @@ namespace chaiscript
     template<typename T1, typename T2, typename T3, typename T4, typename T5>
       struct Exception_Handler_Impl5 : Exception_Handler_Base
       {
+        virtual ~Exception_Handler_Impl5() {}
+
         virtual void handle(const Boxed_Value &bv, const Dispatch_Engine &t_engine)
         {
           throw_type<T1>(bv, t_engine);
diff --git a/include/chaiscript/dispatchkit/proxy_functions_detail.hpp b/include/chaiscript/dispatchkit/proxy_functions_detail.hpp
index f114726..5260ec1 100644
--- a/include/chaiscript/dispatchkit/proxy_functions_detail.hpp
+++ b/include/chaiscript/dispatchkit/proxy_functions_detail.hpp
@@ -88,7 +88,7 @@ namespace chaiscript
       template<typename Ret, typename ... Params>
         bool compare_types_cast(Ret (*)(Params...),
              const std::vector<Boxed_Value> &params, const Dynamic_Cast_Conversions &t_conversions)
-        {
+       {
           try {
             Try_Cast<Params...>::do_try(params, 0, t_conversions);
           } catch (const exception::bad_boxed_cast &) {
diff --git a/include/chaiscript/language/chaiscript_engine.hpp b/include/chaiscript/language/chaiscript_engine.hpp
index 581e8ed..d3fefc6 100644
--- a/include/chaiscript/language/chaiscript_engine.hpp
+++ b/include/chaiscript/language/chaiscript_engine.hpp
@@ -483,19 +483,20 @@ namespace chaiscript
         try {
           const std::string appendedpath = m_usepaths[i] + t_filename;
 
-          chaiscript::detail::threading::lock_guard<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
-          chaiscript::detail::threading::shared_lock<chaiscript::detail::threading::shared_mutex> l2(m_mutex);
+          chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::recursive_mutex> l(m_use_mutex);
+          chaiscript::detail::threading::unique_lock<chaiscript::detail::threading::shared_mutex> l2(m_mutex);
 
           if (m_used_files.count(appendedpath) == 0)
           {
-            m_used_files.insert(appendedpath);
             l2.unlock();
             eval_file(appendedpath);
-          }
+            l2.lock();
+            m_used_files.insert(appendedpath);
+           }
 
           return; // return, we loaded it, or it was already loaded
         } catch (const exception::file_not_found_error &) {
-          if (i == m_usepaths.size() - 1)
+           if (i == m_usepaths.size() - 1)
           {
             throw exception::file_not_found_error(t_filename);
           }
diff --git a/src/reflection.cpp b/src/reflection.cpp
index 40e9efe..b7cb1c5 100644
--- a/src/reflection.cpp
+++ b/src/reflection.cpp
@@ -44,6 +44,12 @@ chaiscript::AST_NodePtr get_parse_tree(const chaiscript::Const_Proxy_Function &t
 }
 
 
+#ifdef __llvm__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
+#endif
+
+
 CHAISCRIPT_MODULE_EXPORT  chaiscript::ModulePtr create_chaiscript_module_reflection()
 {
   chaiscript::ModulePtr m(new chaiscript::Module());
@@ -98,6 +104,11 @@ CHAISCRIPT_MODULE_EXPORT  chaiscript::ModulePtr create_chaiscript_module_reflect
   return m;
 }
 
+#ifdef __llvm__
+#pragma clang diagnostic pop
+#endif
+
+
 
 #ifdef CHAISCRIPT_MSVC
 #pragma warning(pop)
diff --git a/src/stl_extra.cpp b/src/stl_extra.cpp
index 9868366..e97dfb3 100644
--- a/src/stl_extra.cpp
+++ b/src/stl_extra.cpp
@@ -11,11 +11,19 @@
 #pragma warning(disable : 4190)
 #endif
 
+#ifdef __llvm__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
+#endif
+
 CHAISCRIPT_MODULE_EXPORT chaiscript::ModulePtr create_chaiscript_module_stl_extra()
 {
   return chaiscript::bootstrap::standard_library::list_type<std::list<chaiscript::Boxed_Value> >("List");
 }
 
+#ifdef __llvm__
+#pragma clang diagnostic pop
+#endif
 
 #ifdef CHAISCRIPT_MSVC
 #pragma warning(pop)
diff --git a/src/test_module.cpp b/src/test_module.cpp
index 3e2f21e..5b1aa0a 100644
--- a/src/test_module.cpp
+++ b/src/test_module.cpp
@@ -49,6 +49,10 @@ int *get_new_int()
 #pragma warning(disable : 4190)
 #endif
 
+#ifdef __llvm__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
+#endif
 
 CHAISCRIPT_MODULE_EXPORT  chaiscript::ModulePtr create_chaiscript_module_test_module()
 {
@@ -86,6 +90,10 @@ CHAISCRIPT_MODULE_EXPORT  chaiscript::ModulePtr create_chaiscript_module_test_mo
 }
 
 
+#ifdef __llvm__
+#pragma clang diagnostic pop
+#endif
+
 #ifdef CHAISCRIPT_MSVC
 #pragma warning(pop)
 #endif
diff --git a/unittests/multithreaded_test.cpp b/unittests/multithreaded_test.cpp
index 806dfb6..3b8c862 100644
--- a/unittests/multithreaded_test.cpp
+++ b/unittests/multithreaded_test.cpp
@@ -24,13 +24,17 @@ int expected_value(int num_iters)
 
 void do_work(chaiscript::ChaiScript &c, int id)
 {
-  std::stringstream ss;
-  ss << "MyVar" << rand();
-  c.add(chaiscript::var(5), ss.str());
-  ss.str("");
-  ss << id;
-  c.use("multithreaded_work.inc");
-  c("do_chai_work(4000, " + ss.str() + ");");
+  try{
+    std::stringstream ss;
+    ss << "MyVar" << rand();
+    c.add(chaiscript::var(5), ss.str());
+    ss.str("");
+    ss << id;
+    c.use("multithreaded_work.inc");
+    c("do_chai_work(4000, " + ss.str() + ");");
+  } catch (const std::exception &e) {
+    std::cout << "exception: " << e.what() << " thread:  " << id;
+  }
 }
 
 int main()
@@ -80,6 +84,7 @@ int main()
   }
 
 
+
   for (int i = 0; i < num_threads; ++i)
   {
     std::stringstream ss;