+extern std::string datadir;
+extern std::string user_dir;
+
+/** maps a virtual resource path to a real path (ie. levels/bla is mapped to
+ * $DATADIR/levels/bla or $HOME/.supertux/levels/bla)
+ * All paths inside the game should be handled in as virtual paths and then
+ * expanded with this function just before the call to fopen or std::ifstream.
+ */
+std::string get_resource_filename(const std::string& resource);
+
+void load_shared();
+void unload_shared();
+
+#endif