diff --git a/ndn-cpp/encoding/BinaryXMLEncoder.hpp b/ndn-cpp/encoding/BinaryXMLEncoder.hpp
index 2ae5196..f31de46 100644
--- a/ndn-cpp/encoding/BinaryXMLEncoder.hpp
+++ b/ndn-cpp/encoding/BinaryXMLEncoder.hpp
@@ -7,6 +7,7 @@
 #define	NDN_BINARYXMLENCODER_HPP
 
 #include <vector>
+#include "../common.hpp"
 #include "../c/util/ndn_realloc.h"
 #include "../c/encoding/BinaryXMLEncoder.h"
 
@@ -27,12 +28,11 @@
   }
   
   /**
-   * Copy the encoded bytes to the end of the buffer.
-   * @param buffer a vector to receive the copy
+   * Return the output as a shared_ptr.
    */
-  void appendTo(std::vector<unsigned char> &buffer) 
+  ptr_lib::shared_ptr<std::vector<unsigned char> > getOutput() 
   {
-    buffer.insert(buffer.end(), output.array, output.array + offset);
+    return ptr_lib::shared_ptr<std::vector<unsigned char> >(new std::vector<unsigned char>(output.array, output.array + offset));
   }
 };
 
diff --git a/ndn-cpp/encoding/BinaryXMLWireFormat.cpp b/ndn-cpp/encoding/BinaryXMLWireFormat.cpp
index 0c1f4d2..2faa4c3 100644
--- a/ndn-cpp/encoding/BinaryXMLWireFormat.cpp
+++ b/ndn-cpp/encoding/BinaryXMLWireFormat.cpp
@@ -18,7 +18,7 @@
 
 BinaryXMLWireFormat BinaryXMLWireFormat::instance_;
 
-void BinaryXMLWireFormat::encodeInterest(const Interest &interest, vector<unsigned char> &output) 
+ptr_lib::shared_ptr<vector<unsigned char> > BinaryXMLWireFormat::encodeInterest(const Interest &interest) 
 {
   struct ndn_NameComponent nameComponents[100];
   struct ndn_ExcludeEntry excludeEntries[100];
@@ -31,7 +31,7 @@
   BinaryXMLEncoder encoder;
   ndn_encodeBinaryXMLInterest(&interestStruct, &encoder);
      
-  encoder.appendTo(output);
+  return encoder.getOutput();
 }
 
 void BinaryXMLWireFormat::decodeInterest(Interest &interest, const unsigned char *input, unsigned int inputLength)
@@ -51,7 +51,7 @@
   interest.set(interestStruct);
 }
 
-void BinaryXMLWireFormat::encodeContentObject(const ContentObject &contentObject, vector<unsigned char> &output) 
+ptr_lib::shared_ptr<vector<unsigned char> > BinaryXMLWireFormat::encodeContentObject(const ContentObject &contentObject) 
 {
   struct ndn_NameComponent nameComponents[100];
   struct ndn_ContentObject contentObjectStruct;
@@ -62,7 +62,7 @@
   BinaryXMLEncoder encoder;
   ndn_encodeBinaryXMLContentObject(&contentObjectStruct, &encoder);
      
-  encoder.appendTo(output);
+  return encoder.getOutput();
 }
 
 void BinaryXMLWireFormat::decodeContentObject(ContentObject &contentObject, const unsigned char *input, unsigned int inputLength)
diff --git a/ndn-cpp/encoding/BinaryXMLWireFormat.hpp b/ndn-cpp/encoding/BinaryXMLWireFormat.hpp
index d35660f..20ebacd 100644
--- a/ndn-cpp/encoding/BinaryXMLWireFormat.hpp
+++ b/ndn-cpp/encoding/BinaryXMLWireFormat.hpp
@@ -12,10 +12,10 @@
 
 class BinaryXMLWireFormat : public WireFormat {
 public:
-  virtual void encodeInterest(const Interest &interest, std::vector<unsigned char> &output);
+  virtual ptr_lib::shared_ptr<std::vector<unsigned char> > encodeInterest(const Interest &interest);
   virtual void decodeInterest(Interest &interest, const unsigned char *input, unsigned int inputLength);
 
-  virtual void encodeContentObject(const ContentObject &contentObject, std::vector<unsigned char> &output);
+  virtual ptr_lib::shared_ptr<std::vector<unsigned char> > encodeContentObject(const ContentObject &contentObject);
   virtual void decodeContentObject(ContentObject &contentObject, const unsigned char *input, unsigned int inputLength);
   
   static BinaryXMLWireFormat &instance() { return instance_; }
diff --git a/ndn-cpp/encoding/WireFormat.cpp b/ndn-cpp/encoding/WireFormat.cpp
index 5d46241..238ce9c 100644
--- a/ndn-cpp/encoding/WireFormat.cpp
+++ b/ndn-cpp/encoding/WireFormat.cpp
@@ -9,7 +9,7 @@
 using namespace std;
 
 namespace ndn {
-void WireFormat::encodeInterest(const Interest &interest, vector<unsigned char> &output) 
+ptr_lib::shared_ptr<vector<unsigned char> > WireFormat::encodeInterest(const Interest &interest) 
 {
   throw logic_error("unimplemented");
 }
@@ -18,7 +18,7 @@
   throw logic_error("unimplemented");
 }
 
-void WireFormat::encodeContentObject(const ContentObject &contentObject, vector<unsigned char> &output) 
+ptr_lib::shared_ptr<vector<unsigned char> > WireFormat::encodeContentObject(const ContentObject &contentObject) 
 {
   throw logic_error("unimplemented");
 }
diff --git a/ndn-cpp/encoding/WireFormat.hpp b/ndn-cpp/encoding/WireFormat.hpp
index df532e9..1afe25f 100644
--- a/ndn-cpp/encoding/WireFormat.hpp
+++ b/ndn-cpp/encoding/WireFormat.hpp
@@ -6,6 +6,7 @@
 #ifndef NDN_WIREFORMAT_HPP
 #define	NDN_WIREFORMAT_HPP
 
+#include "../common.hpp"
 #include <vector>
 
 namespace ndn {
@@ -15,10 +16,10 @@
   
 class WireFormat {
 public:
-  virtual void encodeInterest(const Interest &interest, std::vector<unsigned char> &output);
+  virtual ptr_lib::shared_ptr<std::vector<unsigned char> > encodeInterest(const Interest &interest);
   virtual void decodeInterest(Interest &interest, const unsigned char *input, unsigned int inputLength);
 
-  virtual void encodeContentObject(const ContentObject &contentObject, std::vector<unsigned char> &output);
+  virtual ptr_lib::shared_ptr<std::vector<unsigned char> > encodeContentObject(const ContentObject &contentObject);
   virtual void decodeContentObject(ContentObject &contentObject, const unsigned char *input, unsigned int inputLength);
 };