diff --git a/ndn-cpp/encoding/binary-xml-element-reader.hpp b/ndn-cpp/encoding/binary-xml-element-reader.hpp
index 5aed8a0..f353e97 100644
--- a/ndn-cpp/encoding/binary-xml-element-reader.hpp
+++ b/ndn-cpp/encoding/binary-xml-element-reader.hpp
@@ -29,7 +29,7 @@
    * @param elementLength length of element
    */
   virtual void 
-  onReceivedElement(const uint8_t *element, unsigned int elementLength) = 0;
+  onReceivedElement(const uint8_t *element, size_t elementLength) = 0;
   
 private:
   /**
@@ -39,7 +39,7 @@
    * @param elementLength
    */
   static void 
-  staticOnReceivedElement(struct ndn_ElementListener *self, uint8_t *element, unsigned int elementLength);
+  staticOnReceivedElement(struct ndn_ElementListener *self, uint8_t *element, size_t elementLength);
 };
 
 }