library/win32: conform to the template query signature

library_win32.cpp

@@ -22,16 +22,26 @@ library::library (const std::experimental::filesystem::path &path):
 }
 
 
+//-----------------------------------------------------------------------------
+library::library (library &&rhs):
+    m_handle (nullptr)
+{
+    std::swap (m_handle, rhs.m_handle);
+}
+
+
+//-----------------------------------------------------------------------------
+library&
+library::operator= (cruft::library &&rhs)
+{
+    std::swap (m_handle, rhs.m_handle);
+    return *this;
+}
+
+
 //-----------------------------------------------------------------------------
 library::~library ()
 {
+    if (m_handle)
         FreeLibrary (m_handle);
 }
-
-
-///////////////////////////////////////////////////////////////////////////////
-void*
-library::symbol (const char *name)
-{
-    return reinterpret_cast<void*> (GetProcAddress (m_handle, name));
-}

library_win32.hpp

@@ -9,6 +9,8 @@
 #ifndef __UTIL_LIBRARY_WIN32_HPP
 #define __UTIL_LIBRARY_WIN32_HPP
 
+#include <cruft/util/cast.hpp>
+
 #include <windows.h>
 
 #include <experimental/filesystem>
@@ -18,9 +20,21 @@ namespace cruft {
         class library {
         public:
             explicit library (const std::experimental::filesystem::path&);
+            library (library const&) = delete;
+            library& operator=(library const&) = delete;
+            library (library&&);
+            library& operator= (library&&);
+
             ~library ();
 
-            void* symbol (const char *name);
+            template <typename FunctionT>
+            FunctionT
+            symbol (const char *name)
+            {
+                return cast::ffs<FunctionT> (
+                      GetProcAddress (m_handle, name)
+                );
+            }
 
         private:
             HMODULE m_handle;