diff --git a/ndn-cpp/encoding/BinaryXMLEncoder.hpp b/ndn-cpp/encoding/BinaryXMLEncoder.hpp
index c1f8a1f..505b776 100644
--- a/ndn-cpp/encoding/BinaryXMLEncoder.hpp
+++ b/ndn-cpp/encoding/BinaryXMLEncoder.hpp
@@ -44,7 +44,7 @@
    */
   void appendTo(std::vector<unsigned char> &buffer) 
   {
-    buffer.insert(buffer.end(), this->output.array, this->output.array + this->offset);
+    buffer.insert(buffer.end(), output.array, output.array + offset);
   }
 };