diff --git a/tinyxml2.h b/tinyxml2.h
index 887e173..a640818 100755
--- a/tinyxml2.h
+++ b/tinyxml2.h
@@ -190,7 +190,7 @@ private:
     char*   _end;
 
     StrPair( const StrPair& other );	// not supported
-    void operator=( StrPair& other );	// not supported, use TransferTo()
+    void operator=( const StrPair& other );	// not supported, use TransferTo()
 };