support user data
diff --git a/tinyxml2.cpp b/tinyxml2.cpp
index 4099fc8..d5d8ebb 100755
--- a/tinyxml2.cpp
+++ b/tinyxml2.cpp
@@ -719,6 +719,7 @@
     _parent( 0 ),

     _firstChild( 0 ), _lastChild( 0 ),

     _prev( 0 ), _next( 0 ),

+	_userData( 0 ),

     _memPool( 0 )

 {

 }