diff --git a/src/AbstractBtMessage.h b/src/AbstractBtMessage.h
index fb5daa0e..5b46ce21 100644
--- a/src/AbstractBtMessage.h
+++ b/src/AbstractBtMessage.h
@@ -106,7 +106,7 @@ public:
 
   virtual ~AbstractBtMessage();
 
-  virtual bool isInvalidate() {
+  virtual bool isInvalidate() CXX11_OVERRIDE {
     return invalidate_;
   }
 
@@ -114,7 +114,7 @@ public:
     invalidate_ = invalidate;
   }
 
-  virtual bool isUploading() {
+  virtual bool isUploading() CXX11_OVERRIDE {
     return uploading_;
   }
 
@@ -137,19 +137,19 @@ public:
 
   void setPeer(const std::shared_ptr<Peer>& peer);
 
-  virtual void doReceivedAction() {}
+  virtual void doReceivedAction() CXX11_OVERRIDE {}
 
-  virtual void validate();
+  virtual void validate() CXX11_OVERRIDE;
 
-  virtual void onQueued() {}
+  virtual void onQueued() CXX11_OVERRIDE {}
 
   virtual void onAbortOutstandingRequestEvent
-  (const BtAbortOutstandingRequestEvent& event) {}
+  (const BtAbortOutstandingRequestEvent& event) CXX11_OVERRIDE {}
 
   virtual void onCancelSendingPieceEvent
-  (const BtCancelSendingPieceEvent& event) {}
+  (const BtCancelSendingPieceEvent& event) CXX11_OVERRIDE {}
 
-  virtual void onChokingEvent(const BtChokingEvent& event) {}
+  virtual void onChokingEvent(const BtChokingEvent& event) CXX11_OVERRIDE {}
 
   void setBtMessageValidator(std::unique_ptr<BtMessageValidator> validator);
 
diff --git a/src/AbstractCommand.h b/src/AbstractCommand.h
index 8230a040..fd85980d 100644
--- a/src/AbstractCommand.h
+++ b/src/AbstractCommand.h
@@ -244,7 +244,7 @@ public:
    bool incNumConnection = true);
 
   virtual ~AbstractCommand();
-  bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 };
 
 // Returns proxy URI for given protocol.  If no proxy URI is defined,
diff --git a/src/AbstractDiskWriter.h b/src/AbstractDiskWriter.h
index 7088a1c7..64e8ade0 100644
--- a/src/AbstractDiskWriter.h
+++ b/src/AbstractDiskWriter.h
@@ -71,28 +71,31 @@ public:
   AbstractDiskWriter(const std::string& filename);
   virtual ~AbstractDiskWriter();
 
-  virtual void openFile(int64_t totalLength = 0);
+  virtual void openFile(int64_t totalLength = 0) CXX11_OVERRIDE;
 
-  virtual void closeFile();
+  virtual void closeFile() CXX11_OVERRIDE;
 
-  virtual void openExistingFile(int64_t totalLength = 0);
+  virtual void openExistingFile(int64_t totalLength = 0) CXX11_OVERRIDE;
 
-  virtual void writeData(const unsigned char* data, size_t len, int64_t offset);
+  virtual void writeData(const unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE;
 
-  virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset);
+  virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE;
 
-  virtual void truncate(int64_t length);
+  virtual void truncate(int64_t length) CXX11_OVERRIDE;
 
   // File must be opened before calling this function.
-  virtual void allocate(int64_t offset, int64_t length, bool sparse);
+  virtual void allocate(int64_t offset, int64_t length, bool sparse)
+     CXX11_OVERRIDE;
 
-  virtual int64_t size();
+  virtual int64_t size() CXX11_OVERRIDE;
 
-  virtual void enableReadOnly();
+  virtual void enableReadOnly() CXX11_OVERRIDE;
 
-  virtual void disableReadOnly();
+  virtual void disableReadOnly() CXX11_OVERRIDE;
 
-  virtual void enableMmap();
+  virtual void enableMmap() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/AbstractHttpServerResponseCommand.h b/src/AbstractHttpServerResponseCommand.h
index f972da90..431351b8 100644
--- a/src/AbstractHttpServerResponseCommand.h
+++ b/src/AbstractHttpServerResponseCommand.h
@@ -73,7 +73,7 @@ public:
 
   virtual ~AbstractHttpServerResponseCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/AbstractOptionHandler.h b/src/AbstractOptionHandler.h
index 5af9cc10..54f80876 100644
--- a/src/AbstractOptionHandler.h
+++ b/src/AbstractOptionHandler.h
@@ -64,66 +64,67 @@ public:
 
   virtual ~AbstractOptionHandler();
 
-  virtual void parse(Option& option, const std::string& arg) const;
+  virtual void parse(Option& option, const std::string& arg) const
+    CXX11_OVERRIDE;
 
-  virtual bool hasTag(uint32_t tag) const;
+  virtual bool hasTag(uint32_t tag) const CXX11_OVERRIDE;
 
-  virtual void addTag(uint32_t tag);
+  virtual void addTag(uint32_t tag) CXX11_OVERRIDE;
 
-  virtual std::string toTagString() const;
+  virtual std::string toTagString() const CXX11_OVERRIDE;
 
-  virtual const char* getName() const;
+  virtual const char* getName() const CXX11_OVERRIDE;
 
-  virtual const char* getDescription() const
+  virtual const char* getDescription() const CXX11_OVERRIDE
   {
     return description_;
   }
 
-  virtual const std::string& getDefaultValue() const
+  virtual const std::string& getDefaultValue() const CXX11_OVERRIDE
   {
     return defaultValue_;
   }
 
-  virtual const Pref* getPref() const
+  virtual const Pref* getPref() const CXX11_OVERRIDE
   {
     return pref_;
   }
 
-  virtual char getShortName() const
+  virtual char getShortName() const CXX11_OVERRIDE
   {
     return shortName_;
   }
 
-  virtual OptionHandler::ARG_TYPE getArgType() const
+  virtual OptionHandler::ARG_TYPE getArgType() const CXX11_OVERRIDE
   {
     return argType_;
   }
 
-  virtual bool isHidden() const;
+  virtual bool isHidden() const CXX11_OVERRIDE;
 
-  virtual void hide();
+  virtual void hide() CXX11_OVERRIDE;
 
-  virtual bool getEraseAfterParse() const;
+  virtual bool getEraseAfterParse() const CXX11_OVERRIDE;
 
-  virtual void setEraseAfterParse(bool f);
+  virtual void setEraseAfterParse(bool f) CXX11_OVERRIDE;
 
-  virtual bool getInitialOption() const;
+  virtual bool getInitialOption() const CXX11_OVERRIDE;
 
-  virtual void setInitialOption(bool f);
+  virtual void setInitialOption(bool f) CXX11_OVERRIDE;
 
-  virtual bool getChangeOption() const;
+  virtual bool getChangeOption() const CXX11_OVERRIDE;
 
-  virtual void setChangeOption(bool f);
+  virtual void setChangeOption(bool f) CXX11_OVERRIDE;
 
-  virtual bool getChangeOptionForReserved() const;
+  virtual bool getChangeOptionForReserved() const CXX11_OVERRIDE;
 
-  virtual void setChangeOptionForReserved(bool f);
+  virtual void setChangeOptionForReserved(bool f) CXX11_OVERRIDE;
 
-  virtual bool getChangeGlobalOption() const;
+  virtual bool getChangeGlobalOption() const CXX11_OVERRIDE;
 
-  virtual void setChangeGlobalOption(bool f);
+  virtual void setChangeGlobalOption(bool f) CXX11_OVERRIDE;
 
-  virtual bool getCumulative() const;
+  virtual bool getCumulative() const CXX11_OVERRIDE;
 
   virtual void setCumulative(bool f);
 
diff --git a/src/AbstractProxyRequestCommand.h b/src/AbstractProxyRequestCommand.h
index 68fd8af1..e394a2a4 100644
--- a/src/AbstractProxyRequestCommand.h
+++ b/src/AbstractProxyRequestCommand.h
@@ -48,7 +48,7 @@ private:
 
   std::shared_ptr<HttpConnection> httpConnection_;
 protected:
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 
   const std::shared_ptr<HttpConnection>& getHttpConnection() const
   {
diff --git a/src/AbstractSingleDiskAdaptor.h b/src/AbstractSingleDiskAdaptor.h
index 0a23e84a..209bf571 100644
--- a/src/AbstractSingleDiskAdaptor.h
+++ b/src/AbstractSingleDiskAdaptor.h
@@ -52,40 +52,42 @@ public:
 
   virtual ~AbstractSingleDiskAdaptor();
 
-  virtual void initAndOpenFile();
+  virtual void initAndOpenFile() CXX11_OVERRIDE;
 
-  virtual void openFile();
+  virtual void openFile() CXX11_OVERRIDE;
 
-  virtual void closeFile();
+  virtual void closeFile() CXX11_OVERRIDE;
 
-  virtual void openExistingFile();
+  virtual void openExistingFile() CXX11_OVERRIDE;
 
   virtual void writeData(const unsigned char* data, size_t len,
-                         int64_t offset);
+                         int64_t offset) CXX11_OVERRIDE;
 
-  virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset);
+  virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE;
 
-  virtual void writeCache(const WrDiskCacheEntry* entry);
+  virtual void writeCache(const WrDiskCacheEntry* entry) CXX11_OVERRIDE;
 
-  virtual bool fileExists();
+  virtual bool fileExists() CXX11_OVERRIDE;
 
-  virtual int64_t size();
+  virtual int64_t size() CXX11_OVERRIDE;
 
-  virtual void truncate(int64_t length);
+  virtual void truncate(int64_t length) CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<FileAllocationIterator> fileAllocationIterator();
+  virtual std::unique_ptr<FileAllocationIterator> fileAllocationIterator()
+    CXX11_OVERRIDE;
 
   // Make sure that DiskWriter is set before calling this function.
-  virtual void enableReadOnly();
+  virtual void enableReadOnly() CXX11_OVERRIDE;
 
   // Make sure that DiskWriter is set before calling this function.
-  virtual void disableReadOnly();
+  virtual void disableReadOnly() CXX11_OVERRIDE;
 
-  virtual bool isReadOnlyEnabled() const { return readOnly_; }
+  virtual bool isReadOnlyEnabled() const CXX11_OVERRIDE { return readOnly_; }
 
-  virtual void enableMmap();
+  virtual void enableMmap() CXX11_OVERRIDE;
 
-  virtual void cutTrailingGarbage();
+  virtual void cutTrailingGarbage() CXX11_OVERRIDE;
 
   virtual const std::string& getFilePath() = 0;
 
diff --git a/src/ActivePeerConnectionCommand.h b/src/ActivePeerConnectionCommand.h
index 29730907..0aeaa6d7 100644
--- a/src/ActivePeerConnectionCommand.h
+++ b/src/ActivePeerConnectionCommand.h
@@ -71,7 +71,7 @@ public:
 
   virtual ~ActivePeerConnectionCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void makeNewConnections(int num);
 
diff --git a/src/AdaptiveFileAllocationIterator.h b/src/AdaptiveFileAllocationIterator.h
index f66b6b0f..6d0c804d 100644
--- a/src/AdaptiveFileAllocationIterator.h
+++ b/src/AdaptiveFileAllocationIterator.h
@@ -59,13 +59,13 @@ public:
 
   virtual ~AdaptiveFileAllocationIterator();
 
-  virtual void allocateChunk();
+  virtual void allocateChunk() CXX11_OVERRIDE;
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
-  virtual int64_t getCurrentLength();
+  virtual int64_t getCurrentLength() CXX11_OVERRIDE;
 
-  virtual int64_t getTotalLength();
+  virtual int64_t getTotalLength() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/AdaptiveURISelector.h b/src/AdaptiveURISelector.h
index d4dfdab2..92535467 100644
--- a/src/AdaptiveURISelector.h
+++ b/src/AdaptiveURISelector.h
@@ -78,12 +78,14 @@ public:
 
   virtual std::string select
   (FileEntry* fileEntry,
-   const std::vector<std::pair<size_t, std::string> >& usedHosts);
+   const std::vector<std::pair<size_t, std::string> >& usedHosts)
+    CXX11_OVERRIDE;
 
   virtual void tuneDownloadCommand(const std::deque<std::string>& uris,
-                                   DownloadCommand* command);
+                                   DownloadCommand* command)
+    CXX11_OVERRIDE;
 
-  virtual void resetCounters();
+  virtual void resetCounters() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/AnonDiskWriterFactory.h b/src/AnonDiskWriterFactory.h
index 4d3c0116..573d203e 100644
--- a/src/AnonDiskWriterFactory.h
+++ b/src/AnonDiskWriterFactory.h
@@ -49,6 +49,7 @@ public:
   virtual ~AnonDiskWriterFactory() {}
 
   virtual std::unique_ptr<DiskWriter> newDiskWriter(const std::string& filename)
+    CXX11_OVERRIDE
   {
     return make_unique<DiskWriterType>();
   }
diff --git a/src/ApiCallbackDownloadEventListener.h b/src/ApiCallbackDownloadEventListener.h
index a681fe98..81cae4ff 100644
--- a/src/ApiCallbackDownloadEventListener.h
+++ b/src/ApiCallbackDownloadEventListener.h
@@ -45,7 +45,8 @@ public:
                                    DownloadEventCallback callback,
                                    void* userData);
   virtual ~ApiCallbackDownloadEventListener();
-  virtual void onEvent(DownloadEvent event, const RequestGroup* group);
+  virtual void onEvent(DownloadEvent event, const RequestGroup* group)
+    CXX11_OVERRIDE;
 private:
   Session* session_;
   DownloadEventCallback callback_;
diff --git a/src/AppleMessageDigestImpl.cc b/src/AppleMessageDigestImpl.cc
index b92bcd36..3416c257 100644
--- a/src/AppleMessageDigestImpl.cc
+++ b/src/AppleMessageDigestImpl.cc
@@ -51,20 +51,20 @@ public:
   MessageDigestBase() { reset(); }
   virtual ~MessageDigestBase() {}
 
-  virtual size_t getDigestLength() const {
+  virtual size_t getDigestLength() const CXX11_OVERRIDE {
     return dlen;
   }
-  virtual void reset() {
+  virtual void reset() CXX11_OVERRIDE {
     init_fn(&ctx_);
   }
-  virtual void update(const void* data, size_t length) {
+  virtual void update(const void* data, size_t length) CXX11_OVERRIDE {
     while (length) {
       CC_LONG l = std::min(length, (size_t)std::numeric_limits<uint32_t>::max());
       update_fn(&ctx_, data, l);
       length -= l;
     }
   }
-  virtual void digest(unsigned char* md) {
+  virtual void digest(unsigned char* md) CXX11_OVERRIDE {
     final_fn(md, &ctx_);
   }
 private:
diff --git a/src/AppleTLSContext.h b/src/AppleTLSContext.h
index d7ac6c25..e5c7cbba 100644
--- a/src/AppleTLSContext.h
+++ b/src/AppleTLSContext.h
@@ -58,26 +58,27 @@ public:
 
   // private key `keyfile' must be decrypted.
   virtual bool addCredentialFile(const std::string& certfile,
-                                 const std::string& keyfile);
+                                 const std::string& keyfile) CXX11_OVERRIDE;
 
-  virtual bool addSystemTrustedCACerts() {
+  virtual bool addSystemTrustedCACerts() CXX11_OVERRIDE {
     return true;
   }
 
   // certfile can contain multiple certificates.
-  virtual bool addTrustedCACertFile(const std::string& certfile);
+  virtual bool addTrustedCACertFile(const std::string& certfile)
+    CXX11_OVERRIDE;
 
-  virtual bool good() const {
+  virtual bool good() const CXX11_OVERRIDE {
     return true;
   }
-  virtual TLSSessionSide getSide() const {
+  virtual TLSSessionSide getSide() const CXX11_OVERRIDE {
     return side_;
   }
 
-  virtual bool getVerifyPeer() const {
+  virtual bool getVerifyPeer() const CXX11_OVERRIDE {
     return verifyPeer_;
   }
-  virtual void setVerifyPeer(bool verify) {
+  virtual void setVerifyPeer(bool verify) CXX11_OVERRIDE {
     verifyPeer_ = verify;
   }
 
diff --git a/src/AppleTLSSession.h b/src/AppleTLSSession.h
index 59a3e917..e776a294 100644
--- a/src/AppleTLSSession.h
+++ b/src/AppleTLSSession.h
@@ -58,34 +58,34 @@ public:
   // Initializes SSL/TLS session. The |sockfd| is the underlying
   // tranport socket. This function returns TLS_ERR_OK if it
   // succeeds, or TLS_ERR_ERROR.
-  virtual int init(sock_t sockfd);
+  virtual int init(sock_t sockfd) CXX11_OVERRIDE;
 
   // Sets |hostname| for TLS SNI extension. This is only meaningful for
   // client side session. This function returns TLS_ERR_OK if it
   // succeeds, or TLS_ERR_ERROR.
-  virtual int setSNIHostname(const std::string& hostname);
+  virtual int setSNIHostname(const std::string& hostname) CXX11_OVERRIDE;
 
   // Closes the SSL/TLS session. Don't close underlying transport
   // socket. This function returns TLS_ERR_OK if it succeeds, or
   // TLS_ERR_ERROR.
-  virtual int closeConnection();
+  virtual int closeConnection() CXX11_OVERRIDE;
 
   // Returns TLS_WANT_READ if SSL/TLS session needs more data from
   // remote endpoint to proceed, or TLS_WANT_WRITE if SSL/TLS session
   // needs to write more data to proceed. If SSL/TLS session needs
   // neither read nor write data at the moment, return value is
   // undefined.
-  virtual int checkDirection();
+  virtual int checkDirection() CXX11_OVERRIDE;
 
   // Sends |data| with length |len|. This function returns the number
   // of bytes sent if it succeeds, or TLS_ERR_WOULDBLOCK if the
   // underlying tranport blocks, or TLS_ERR_ERROR.
-  virtual ssize_t writeData(const void* data, size_t len);
+  virtual ssize_t writeData(const void* data, size_t len) CXX11_OVERRIDE;
 
   // Receives data into |data| with length |len|. This function returns
   // the number of bytes received if it succeeds, or TLS_ERR_WOULDBLOCK
   // if the underlying tranport blocks, or TLS_ERR_ERROR.
-  virtual ssize_t readData(void* data, size_t len);
+  virtual ssize_t readData(void* data, size_t len) CXX11_OVERRIDE;
 
   // Performs client side handshake. The |hostname| is the hostname of
   // the remote endpoint and is used to verify its certificate. This
@@ -93,15 +93,16 @@ public:
   // if the underlying transport blocks, or TLS_ERR_ERROR.
   // When returning TLS_ERR_ERROR, provide certificate validation error
   // in |handshakeErr|.
-  virtual int tlsConnect(const std::string& hostname, std::string& handshakeErr);
+  virtual int tlsConnect
+  (const std::string& hostname, std::string& handshakeErr) CXX11_OVERRIDE;
 
   // Performs server side handshake. This function returns TLS_ERR_OK
   // if it succeeds, or TLS_ERR_WOULDBLOCK if the underlying transport
   // blocks, or TLS_ERR_ERROR.
-  virtual int tlsAccept();
+  virtual int tlsAccept() CXX11_OVERRIDE;
 
   // Returns last error string
-  virtual std::string getLastErrorString();
+  virtual std::string getLastErrorString() CXX11_OVERRIDE;
 
 private:
   static OSStatus SocketWrite(SSLConnectionRef conn, const void* data, size_t* len) {
diff --git a/src/AutoSaveCommand.h b/src/AutoSaveCommand.h
index 69363f5d..ccbd9d92 100644
--- a/src/AutoSaveCommand.h
+++ b/src/AutoSaveCommand.h
@@ -46,9 +46,9 @@ public:
 
   virtual ~AutoSaveCommand();
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BackupIPv4ConnectCommand.h b/src/BackupIPv4ConnectCommand.h
index b6354e7a..fd3b2dfa 100644
--- a/src/BackupIPv4ConnectCommand.h
+++ b/src/BackupIPv4ConnectCommand.h
@@ -70,7 +70,7 @@ public:
                            Command* mainCommand,
                            RequestGroup* requestGroup, DownloadEngine* e);
   ~BackupIPv4ConnectCommand();
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 private:
   std::string ipaddr_;
   uint16_t port_;
diff --git a/src/BtAllowedFastMessage.cc b/src/BtAllowedFastMessage.cc
index c51f1eda..ab5e2cdd 100644
--- a/src/BtAllowedFastMessage.cc
+++ b/src/BtAllowedFastMessage.cc
@@ -67,7 +67,7 @@ namespace {
 struct ThisProgressUpdate : public ProgressUpdate {
   ThisProgressUpdate(const std::shared_ptr<Peer>& peer, size_t index)
     : peer(peer), index(index) {}
-  virtual void update(size_t length, bool complete)
+  virtual void update(size_t length, bool complete) CXX11_OVERRIDE
   {
     if(complete) {
       peer->addAmAllowedIndex(index);
diff --git a/src/BtAllowedFastMessage.h b/src/BtAllowedFastMessage.h
index dfb176e6..c58f5190 100644
--- a/src/BtAllowedFastMessage.h
+++ b/src/BtAllowedFastMessage.h
@@ -50,9 +50,9 @@ public:
   static std::unique_ptr<BtAllowedFastMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate();
+  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtBitfieldMessage.h b/src/BtBitfieldMessage.h
index e88be944..91baa550 100644
--- a/src/BtBitfieldMessage.h
+++ b/src/BtBitfieldMessage.h
@@ -63,13 +63,13 @@ public:
   static std::unique_ptr<BtBitfieldMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual unsigned char* createMessage();
+  virtual unsigned char* createMessage() CXX11_OVERRIDE;
 
-  virtual size_t getMessageLength();
+  virtual size_t getMessageLength() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtBitfieldMessageValidator.h b/src/BtBitfieldMessageValidator.h
index b53e7335..606250a3 100644
--- a/src/BtBitfieldMessageValidator.h
+++ b/src/BtBitfieldMessageValidator.h
@@ -50,7 +50,7 @@ public:
                              size_t numPiece);
   ~BtBitfieldMessageValidator();
 
-  virtual void validate();
+  virtual void validate() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtCancelMessage.h b/src/BtCancelMessage.h
index 42ca7d9c..fd3c601a 100644
--- a/src/BtCancelMessage.h
+++ b/src/BtCancelMessage.h
@@ -50,7 +50,7 @@ public:
   static std::unique_ptr<BtCancelMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtCheckIntegrityEntry.h b/src/BtCheckIntegrityEntry.h
index f04a21d9..14f8f74e 100644
--- a/src/BtCheckIntegrityEntry.h
+++ b/src/BtCheckIntegrityEntry.h
@@ -46,10 +46,12 @@ public:
   virtual ~BtCheckIntegrityEntry();
 
   virtual void onDownloadFinished
-  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e);
+  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e)
+    CXX11_OVERRIDE;
 
   virtual void onDownloadIncomplete
-  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e);
+  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtChokeMessage.cc b/src/BtChokeMessage.cc
index bd6164df..15569a36 100644
--- a/src/BtChokeMessage.cc
+++ b/src/BtChokeMessage.cc
@@ -70,7 +70,7 @@ struct ThisProgressUpdate : public ProgressUpdate {
   ThisProgressUpdate(const std::shared_ptr<Peer>& peer,
                      BtMessageDispatcher* disp)
     : peer(peer), disp(disp) {}
-  virtual void update(size_t length, bool complete)
+  virtual void update(size_t length, bool complete) CXX11_OVERRIDE
   {
     if(complete) {
       peer->amChoking(true);
diff --git a/src/BtChokeMessage.h b/src/BtChokeMessage.h
index 8eca9ca1..23a63a5e 100644
--- a/src/BtChokeMessage.h
+++ b/src/BtChokeMessage.h
@@ -47,14 +47,14 @@ public:
 
   static const char NAME[];
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
   static std::unique_ptr<BtChokeMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual bool sendPredicate() const;
+  virtual bool sendPredicate() const CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate();
+  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtDependency.h b/src/BtDependency.h
index 5f8ba2cb..8613a160 100644
--- a/src/BtDependency.h
+++ b/src/BtDependency.h
@@ -55,7 +55,7 @@ public:
 
   virtual ~BtDependency();
 
-  virtual bool resolve();
+  virtual bool resolve() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtExtendedMessage.h b/src/BtExtendedMessage.h
index 1238c96a..e1df8aec 100644
--- a/src/BtExtendedMessage.h
+++ b/src/BtExtendedMessage.h
@@ -61,15 +61,15 @@ public:
    const unsigned char* data,
    size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual unsigned char* createMessage();
+  virtual unsigned char* createMessage() CXX11_OVERRIDE;
 
-  virtual size_t getMessageLength();
+  virtual size_t getMessageLength() CXX11_OVERRIDE;
 
-  virtual bool sendPredicate() const;
+  virtual bool sendPredicate() const CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
   const std::unique_ptr<ExtensionMessage>& getExtensionMessage() const;
 };
diff --git a/src/BtFileAllocationEntry.h b/src/BtFileAllocationEntry.h
index a4355058..b1a2e902 100644
--- a/src/BtFileAllocationEntry.h
+++ b/src/BtFileAllocationEntry.h
@@ -46,7 +46,8 @@ public:
   virtual ~BtFileAllocationEntry();
 
   virtual void prepareForNextAction
-  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e);
+  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtHandshakeMessage.h b/src/BtHandshakeMessage.h
index 1d9dc78e..03ea2b8b 100644
--- a/src/BtHandshakeMessage.h
+++ b/src/BtHandshakeMessage.h
@@ -74,13 +74,13 @@ public:
 
   static const char NAME[];
 
-  virtual void doReceivedAction() {};
+  virtual void doReceivedAction() CXX11_OVERRIDE {};
 
-  virtual unsigned char* createMessage();
+  virtual unsigned char* createMessage() CXX11_OVERRIDE;
 
-  virtual size_t getMessageLength();
+  virtual size_t getMessageLength() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
   bool isFastExtensionSupported() const;
 
diff --git a/src/BtHandshakeMessageValidator.h b/src/BtHandshakeMessageValidator.h
index 274aa25b..992aec04 100644
--- a/src/BtHandshakeMessageValidator.h
+++ b/src/BtHandshakeMessageValidator.h
@@ -55,7 +55,7 @@ public:
 
   ~BtHandshakeMessageValidator();
 
-  virtual void validate();
+  virtual void validate() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtHaveAllMessage.h b/src/BtHaveAllMessage.h
index 04d8e553..efa31dd6 100644
--- a/src/BtHaveAllMessage.h
+++ b/src/BtHaveAllMessage.h
@@ -50,7 +50,7 @@ public:
   static std::unique_ptr<BtHaveAllMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtHaveMessage.h b/src/BtHaveMessage.h
index 3285774e..45ca574d 100644
--- a/src/BtHaveMessage.h
+++ b/src/BtHaveMessage.h
@@ -50,7 +50,7 @@ public:
   static std::unique_ptr<BtHaveMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtHaveNoneMessage.h b/src/BtHaveNoneMessage.h
index 84ad4f64..f68cd2d5 100644
--- a/src/BtHaveNoneMessage.h
+++ b/src/BtHaveNoneMessage.h
@@ -50,7 +50,7 @@ public:
   static std::unique_ptr<BtHaveNoneMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtInterestedMessage.cc b/src/BtInterestedMessage.cc
index 6423feca..48ce6bd7 100644
--- a/src/BtInterestedMessage.cc
+++ b/src/BtInterestedMessage.cc
@@ -74,7 +74,7 @@ namespace {
 struct ThisProgressUpdate : public ProgressUpdate {
   ThisProgressUpdate(const std::shared_ptr<Peer>& peer)
     : peer(peer) {}
-  virtual void update(size_t length, bool complete)
+  virtual void update(size_t length, bool complete) CXX11_OVERRIDE
   {
     if(complete) {
       peer->amInterested(true);
diff --git a/src/BtInterestedMessage.h b/src/BtInterestedMessage.h
index a0de9a96..a11303a7 100644
--- a/src/BtInterestedMessage.h
+++ b/src/BtInterestedMessage.h
@@ -56,11 +56,11 @@ public:
   static std::unique_ptr<BtInterestedMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual bool sendPredicate() const;
+  virtual bool sendPredicate() const CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate();
+  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate() CXX11_OVERRIDE;
 
   void setPeerStorage(PeerStorage* peerStorage);
 };
diff --git a/src/BtKeepAliveMessage.h b/src/BtKeepAliveMessage.h
index 2e3ac116..8ee940ea 100644
--- a/src/BtKeepAliveMessage.h
+++ b/src/BtKeepAliveMessage.h
@@ -49,13 +49,13 @@ public:
 
   static const char NAME[];
 
-  virtual void doReceivedAction() {}
+  virtual void doReceivedAction() CXX11_OVERRIDE {}
 
-  virtual unsigned char* createMessage();
+  virtual unsigned char* createMessage() CXX11_OVERRIDE;
 
-  virtual size_t getMessageLength();
+  virtual size_t getMessageLength() CXX11_OVERRIDE;
 
-  virtual std::string toString() const
+  virtual std::string toString() const CXX11_OVERRIDE
   {
     return NAME;
   }
diff --git a/src/BtNotInterestedMessage.cc b/src/BtNotInterestedMessage.cc
index abbded28..e91f231c 100644
--- a/src/BtNotInterestedMessage.cc
+++ b/src/BtNotInterestedMessage.cc
@@ -74,7 +74,7 @@ namespace {
 struct ThisProgressUpdate : public ProgressUpdate {
   ThisProgressUpdate(const std::shared_ptr<Peer>& peer)
     : peer(peer) {}
-  virtual void update(size_t length, bool complete)
+  virtual void update(size_t length, bool complete) CXX11_OVERRIDE
   {
     if(complete) {
       peer->amInterested(false);
diff --git a/src/BtNotInterestedMessage.h b/src/BtNotInterestedMessage.h
index 4db1c3f1..9461b726 100644
--- a/src/BtNotInterestedMessage.h
+++ b/src/BtNotInterestedMessage.h
@@ -56,11 +56,11 @@ public:
   static std::unique_ptr<BtNotInterestedMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual bool sendPredicate() const;
+  virtual bool sendPredicate() const CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate();
+  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate() CXX11_OVERRIDE;
 
   void setPeerStorage(PeerStorage* peerStorage);
 };
diff --git a/src/BtPieceMessage.cc b/src/BtPieceMessage.cc
index fb57a171..2301db6d 100644
--- a/src/BtPieceMessage.cc
+++ b/src/BtPieceMessage.cc
@@ -182,7 +182,7 @@ namespace {
 struct PieceSendUpdate : public ProgressUpdate {
   PieceSendUpdate(const std::shared_ptr<Peer>& peer, size_t headerLength)
     : peer(peer), headerLength(headerLength) {}
-  virtual void update(size_t length, bool complete)
+  virtual void update(size_t length, bool complete) CXX11_OVERRIDE
   {
     if(headerLength > 0) {
       size_t m = std::min(headerLength, length);
diff --git a/src/BtPieceMessage.h b/src/BtPieceMessage.h
index f802d919..6ff8470d 100644
--- a/src/BtPieceMessage.h
+++ b/src/BtPieceMessage.h
@@ -95,20 +95,20 @@ public:
   static std::unique_ptr<BtPieceMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
   void createMessageHeader(unsigned char* msgHeader) const;
 
   size_t getMessageHeaderLength();
 
-  virtual void send();
+  virtual void send() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
-  virtual void onChokingEvent(const BtChokingEvent& event);
+  virtual void onChokingEvent(const BtChokingEvent& event) CXX11_OVERRIDE;
 
   virtual void onCancelSendingPieceEvent
-  (const BtCancelSendingPieceEvent& event);
+  (const BtCancelSendingPieceEvent& event) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtPieceMessageValidator.h b/src/BtPieceMessageValidator.h
index 77a21e56..89c9d9b1 100644
--- a/src/BtPieceMessageValidator.h
+++ b/src/BtPieceMessageValidator.h
@@ -53,7 +53,7 @@ public:
 
   ~BtPieceMessageValidator();
 
-  virtual void validate();
+  virtual void validate() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtPortMessage.h b/src/BtPortMessage.h
index c903bc84..0846e125 100644
--- a/src/BtPortMessage.h
+++ b/src/BtPortMessage.h
@@ -68,13 +68,13 @@ public:
   static std::unique_ptr<BtPortMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual unsigned char* createMessage();
+  virtual unsigned char* createMessage() CXX11_OVERRIDE;
 
-  virtual size_t getMessageLength();
+  virtual size_t getMessageLength() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
   void setLocalNode(DHTNode* localNode);
 
diff --git a/src/BtPostDownloadHandler.h b/src/BtPostDownloadHandler.h
index 4ddfddd6..006ab2a8 100644
--- a/src/BtPostDownloadHandler.h
+++ b/src/BtPostDownloadHandler.h
@@ -48,7 +48,7 @@ public:
 
   virtual void
   getNextRequestGroups(std::vector<std::shared_ptr<RequestGroup> >& groups,
-                       RequestGroup* requestGroup);
+                       RequestGroup* requestGroup) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtRejectMessage.h b/src/BtRejectMessage.h
index 34722586..55fc8971 100644
--- a/src/BtRejectMessage.h
+++ b/src/BtRejectMessage.h
@@ -50,7 +50,7 @@ public:
   static std::unique_ptr<BtRejectMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtRequestMessage.h b/src/BtRequestMessage.h
index 15ad37a6..180ff274 100644
--- a/src/BtRequestMessage.h
+++ b/src/BtRequestMessage.h
@@ -58,12 +58,12 @@ public:
   static std::unique_ptr<BtRequestMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual void onQueued();
+  virtual void onQueued() CXX11_OVERRIDE;
 
   virtual void onAbortOutstandingRequestEvent
-  (const BtAbortOutstandingRequestEvent& event);
+  (const BtAbortOutstandingRequestEvent& event) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BtStopDownloadCommand.h b/src/BtStopDownloadCommand.h
index b0dec361..b4dc819b 100644
--- a/src/BtStopDownloadCommand.h
+++ b/src/BtStopDownloadCommand.h
@@ -65,9 +65,9 @@ public:
    DownloadEngine* e,
    time_t timeout);
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 
   void setBtRuntime(const std::shared_ptr<BtRuntime>& btRuntime)
   {
diff --git a/src/BtSuggestPieceMessage.h b/src/BtSuggestPieceMessage.h
index dac39ba4..61df93cd 100644
--- a/src/BtSuggestPieceMessage.h
+++ b/src/BtSuggestPieceMessage.h
@@ -50,7 +50,7 @@ public:
   static std::unique_ptr<BtSuggestPieceMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction() {
+  virtual void doReceivedAction() CXX11_OVERRIDE {
     // TODO Current implementation ignores this message.
   }
 };
diff --git a/src/BtUnchokeMessage.cc b/src/BtUnchokeMessage.cc
index de62c85c..a2eff67f 100644
--- a/src/BtUnchokeMessage.cc
+++ b/src/BtUnchokeMessage.cc
@@ -65,7 +65,7 @@ namespace {
 struct ThisProgressUpdate : public ProgressUpdate {
   ThisProgressUpdate(const std::shared_ptr<Peer>& peer)
     : peer(peer) {}
-  virtual void update(size_t length, bool complete)
+  virtual void update(size_t length, bool complete) CXX11_OVERRIDE
   {
     if(complete) {
       peer->amChoking(false);
diff --git a/src/BtUnchokeMessage.h b/src/BtUnchokeMessage.h
index 57134d71..5435911e 100644
--- a/src/BtUnchokeMessage.h
+++ b/src/BtUnchokeMessage.h
@@ -52,11 +52,11 @@ public:
   static std::unique_ptr<BtUnchokeMessage> create
   (const unsigned char* data, size_t dataLength);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual bool sendPredicate() const;
+  virtual bool sendPredicate() const CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate();
+  virtual std::unique_ptr<ProgressUpdate> getProgressUpdate() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/BufferedFile.h b/src/BufferedFile.h
index 1f242616..10966b2e 100644
--- a/src/BufferedFile.h
+++ b/src/BufferedFile.h
@@ -49,20 +49,20 @@ public:
   virtual ~BufferedFile();
 protected:
   // wrapper for fread. Using 1 for 2nd argument of fread.
-  virtual size_t onRead(void* ptr, size_t count);
+  virtual size_t onRead(void* ptr, size_t count) CXX11_OVERRIDE;
   // wrapper for fwrite. Using 1 for 2nd argument of fwrite.
-  virtual size_t onWrite(const void* ptr, size_t count);
+  virtual size_t onWrite(const void* ptr, size_t count) CXX11_OVERRIDE;
   // wrapper for fgets
-  virtual char* onGets(char* s, int size);
-  virtual int onVprintf(const char* format, va_list va);
+  virtual char* onGets(char* s, int size) CXX11_OVERRIDE;
+  virtual int onVprintf(const char* format, va_list va) CXX11_OVERRIDE;
   // wrapper for fflush
-  virtual int onFlush();
+  virtual int onFlush() CXX11_OVERRIDE;
   // wrapper for fclose
-  virtual int onClose();
-  virtual bool onSupportsColor();
-  virtual bool isError() const;
-  virtual bool isEOF() const;
-  virtual bool isOpen() const;
+  virtual int onClose() CXX11_OVERRIDE;
+  virtual bool onSupportsColor() CXX11_OVERRIDE;
+  virtual bool isError() const CXX11_OVERRIDE;
+  virtual bool isEOF() const CXX11_OVERRIDE;
+  virtual bool isOpen() const CXX11_OVERRIDE;
 private:
   // Don't allow copying;
   BufferedFile(const BufferedFile&);
diff --git a/src/ByteArrayDiskWriter.h b/src/ByteArrayDiskWriter.h
index 4fbeb49c..a9d2dda9 100644
--- a/src/ByteArrayDiskWriter.h
+++ b/src/ByteArrayDiskWriter.h
@@ -49,18 +49,20 @@ public:
   ByteArrayDiskWriter(size_t maxLength = 5*1024*1024);
   virtual ~ByteArrayDiskWriter();
 
-  virtual void initAndOpenFile(int64_t totalLength = 0);
+  virtual void initAndOpenFile(int64_t totalLength = 0) CXX11_OVERRIDE;
 
-  virtual void openFile(int64_t totalLength = 0);
+  virtual void openFile(int64_t totalLength = 0) CXX11_OVERRIDE;
 
-  virtual void closeFile();
+  virtual void closeFile() CXX11_OVERRIDE;
 
-  virtual void openExistingFile(int64_t totalLength = 0);
+  virtual void openExistingFile(int64_t totalLength = 0) CXX11_OVERRIDE;
 
-  virtual void writeData(const unsigned char* data, size_t len, int64_t offset);
-  virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset);
+  virtual void writeData(const unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE;
+  virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE;
 
-  virtual int64_t size();
+  virtual int64_t size() CXX11_OVERRIDE;
 
   void setString(const std::string& s);
 
diff --git a/src/CheckIntegrityCommand.h b/src/CheckIntegrityCommand.h
index 0ce87c40..060548e5 100644
--- a/src/CheckIntegrityCommand.h
+++ b/src/CheckIntegrityCommand.h
@@ -54,9 +54,9 @@ public:
 
   virtual ~CheckIntegrityCommand();
 
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 
-  virtual bool handleException(Exception& e);
+  virtual bool handleException(Exception& e) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/CheckIntegrityDispatcherCommand.h b/src/CheckIntegrityDispatcherCommand.h
index 8a9b419e..92ef37d4 100644
--- a/src/CheckIntegrityDispatcherCommand.h
+++ b/src/CheckIntegrityDispatcherCommand.h
@@ -50,7 +50,8 @@ public:
    CheckIntegrityMan* checkMan,
    DownloadEngine* e);
 protected:
-  virtual std::unique_ptr<Command> createCommand(CheckIntegrityEntry* entry);
+  virtual std::unique_ptr<Command> createCommand(CheckIntegrityEntry* entry)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/CheckIntegrityEntry.h b/src/CheckIntegrityEntry.h
index 106fbd9c..4978cf47 100644
--- a/src/CheckIntegrityEntry.h
+++ b/src/CheckIntegrityEntry.h
@@ -65,13 +65,13 @@ public:
 
   virtual ~CheckIntegrityEntry();
 
-  virtual int64_t getTotalLength();
+  virtual int64_t getTotalLength() CXX11_OVERRIDE;
 
-  virtual int64_t getCurrentLength();
+  virtual int64_t getCurrentLength() CXX11_OVERRIDE;
 
   virtual void validateChunk();
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
   virtual bool isValidationReady() = 0;
 
diff --git a/src/ChecksumCheckIntegrityEntry.h b/src/ChecksumCheckIntegrityEntry.h
index 2c8ce041..f043bb6f 100644
--- a/src/ChecksumCheckIntegrityEntry.h
+++ b/src/ChecksumCheckIntegrityEntry.h
@@ -50,17 +50,17 @@ public:
 
   virtual ~ChecksumCheckIntegrityEntry();
 
-  virtual bool isValidationReady();
+  virtual bool isValidationReady() CXX11_OVERRIDE;
 
-  virtual void initValidator();
+  virtual void initValidator() CXX11_OVERRIDE;
 
   virtual void onDownloadFinished
   (std::vector<std::unique_ptr<Command>>& commands,
-   DownloadEngine* e);
+   DownloadEngine* e) CXX11_OVERRIDE;
 
   virtual void onDownloadIncomplete
   (std::vector<std::unique_ptr<Command>>& commands,
-   DownloadEngine* e);
+   DownloadEngine* e) CXX11_OVERRIDE;
 
   void setRedownload(bool redownload)
   {
diff --git a/src/ChunkedDecodingStreamFilter.h b/src/ChunkedDecodingStreamFilter.h
index 00536be7..7a40f584 100644
--- a/src/ChunkedDecodingStreamFilter.h
+++ b/src/ChunkedDecodingStreamFilter.h
@@ -51,20 +51,20 @@ public:
 
   virtual ~ChunkedDecodingStreamFilter();
 
-  virtual void init();
+  virtual void init() CXX11_OVERRIDE;
 
   virtual ssize_t transform
   (const std::shared_ptr<BinaryStream>& out,
    const std::shared_ptr<Segment>& segment,
-   const unsigned char* inbuf, size_t inlen);
+   const unsigned char* inbuf, size_t inlen) CXX11_OVERRIDE;
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
-  virtual void release();
+  virtual void release() CXX11_OVERRIDE;
 
-  virtual const std::string& getName() const;
+  virtual const std::string& getName() const CXX11_OVERRIDE;
 
-  virtual size_t getBytesProcessed() const
+  virtual size_t getBytesProcessed() const CXX11_OVERRIDE
   {
     return bytesProcessed_;
   }
diff --git a/src/ConnectCommand.h b/src/ConnectCommand.h
index 56cffb88..82d08361 100644
--- a/src/ConnectCommand.h
+++ b/src/ConnectCommand.h
@@ -57,8 +57,8 @@ public:
   void setBackupConnectInfo(const std::shared_ptr<BackupConnectInfo>& info);
   const std::shared_ptr<Request>& getProxyRequest() const;
 protected:
-  virtual bool executeInternal();
-  virtual bool noCheck();
+  virtual bool executeInternal() CXX11_OVERRIDE;
+  virtual bool noCheck() CXX11_OVERRIDE;
 private:
   std::shared_ptr<Request> proxyRequest_;
   std::shared_ptr<BackupConnectInfo> backupConnectionInfo_;
diff --git a/src/ConsoleStatCalc.cc b/src/ConsoleStatCalc.cc
index 55f8d8ea..362f91c5 100644
--- a/src/ConsoleStatCalc.cc
+++ b/src/ConsoleStatCalc.cc
@@ -78,7 +78,7 @@ std::string SizeFormatter::operator()(int64_t size) const
 namespace {
 class AbbrevSizeFormatter:public SizeFormatter {
 protected:
-  virtual std::string format(int64_t size) const
+  virtual std::string format(int64_t size) const CXX11_OVERRIDE
   {
     return util::abbrevSize(size);
   }
@@ -88,7 +88,7 @@ protected:
 namespace {
 class PlainSizeFormatter:public SizeFormatter {
 protected:
-  virtual std::string format(int64_t size) const
+  virtual std::string format(int64_t size) const CXX11_OVERRIDE
   {
     return util::itos(size);
   }
diff --git a/src/ConsoleStatCalc.h b/src/ConsoleStatCalc.h
index d9385054..c2fa02d1 100644
--- a/src/ConsoleStatCalc.h
+++ b/src/ConsoleStatCalc.h
@@ -72,7 +72,7 @@ public:
 
   virtual ~ConsoleStatCalc() {}
 
-  virtual void calculateStat(const DownloadEngine* e);
+  virtual void calculateStat(const DownloadEngine* e) CXX11_OVERRIDE;
 
   void setReadoutVisibility(bool visibility)
   {
diff --git a/src/ContentTypeRequestGroupCriteria.h b/src/ContentTypeRequestGroupCriteria.h
index 67e6be3a..371f163d 100644
--- a/src/ContentTypeRequestGroupCriteria.h
+++ b/src/ContentTypeRequestGroupCriteria.h
@@ -52,7 +52,7 @@ public:
 
   virtual ~ContentTypeRequestGroupCriteria();
 
-  virtual bool match(const RequestGroup* requestGroup) const;
+  virtual bool match(const RequestGroup* requestGroup) const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/CreateRequestCommand.h b/src/CreateRequestCommand.h
index 6701f92b..e4935bb2 100644
--- a/src/CreateRequestCommand.h
+++ b/src/CreateRequestCommand.h
@@ -51,7 +51,7 @@ public:
                        RequestGroup* requestGroup,
                        DownloadEngine* e);
 protected:
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DHTAbstractMessage.h b/src/DHTAbstractMessage.h
index ee5d0620..478f5966 100644
--- a/src/DHTAbstractMessage.h
+++ b/src/DHTAbstractMessage.h
@@ -60,7 +60,7 @@ public:
                      const std::shared_ptr<DHTNode>& remoteNode,
                      const std::string& transactionID = A2STR::NIL);
 
-  virtual bool send();
+  virtual bool send() CXX11_OVERRIDE;
 
   virtual const std::string& getType() const = 0;
 
diff --git a/src/DHTAbstractNodeLookupTask.h b/src/DHTAbstractNodeLookupTask.h
index 3e65f0cf..51b9eaf2 100644
--- a/src/DHTAbstractNodeLookupTask.h
+++ b/src/DHTAbstractNodeLookupTask.h
@@ -128,8 +128,7 @@ protected:
   (std::vector<std::shared_ptr<DHTNode>>& nodes,
    const ResponseMessage* message) = 0;
 
-  virtual void onReceivedInternal
-  (const ResponseMessage* message) {}
+  virtual void onReceivedInternal(const ResponseMessage* message) {}
 
   virtual bool needsAdditionalOutgoingMessage() { return true; }
 
@@ -148,7 +147,7 @@ public:
 
   static const size_t ALPHA = 3;
 
-  virtual void startup()
+  virtual void startup() CXX11_OVERRIDE
   {
     std::vector<std::shared_ptr<DHTNode>> nodes;
     getRoutingTable()->getClosestKNodes(nodes, targetID_);
diff --git a/src/DHTAbstractTask.h b/src/DHTAbstractTask.h
index 65850af7..af249ab5 100644
--- a/src/DHTAbstractTask.h
+++ b/src/DHTAbstractTask.h
@@ -71,7 +71,7 @@ protected:
 public:
   DHTAbstractTask();
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
   DHTRoutingTable* getRoutingTable() const
   {
diff --git a/src/DHTAnnouncePeerMessage.h b/src/DHTAnnouncePeerMessage.h
index 6ba0e758..b8045a26 100644
--- a/src/DHTAnnouncePeerMessage.h
+++ b/src/DHTAnnouncePeerMessage.h
@@ -56,7 +56,7 @@ private:
 
   DHTTokenTracker* tokenTracker_;
 protected:
-  virtual std::string toStringOptional() const;
+  virtual std::string toStringOptional() const CXX11_OVERRIDE;
 public:
   DHTAnnouncePeerMessage(const std::shared_ptr<DHTNode>& localNode,
                          const std::shared_ptr<DHTNode>& remoteNode,
@@ -65,13 +65,13 @@ public:
                          const std::string& token,
                          const std::string& transactionID = A2STR::NIL);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Dict> getArgument();
+  virtual std::shared_ptr<Dict> getArgument() CXX11_OVERRIDE;
 
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
-  virtual void validate() const;
+  virtual void validate() const CXX11_OVERRIDE;
 
   const unsigned char* getInfoHash() const
   {
diff --git a/src/DHTAnnouncePeerReplyMessage.h b/src/DHTAnnouncePeerReplyMessage.h
index 1aa323c1..99dbe7ca 100644
--- a/src/DHTAnnouncePeerReplyMessage.h
+++ b/src/DHTAnnouncePeerReplyMessage.h
@@ -47,13 +47,13 @@ public:
 
   virtual ~DHTAnnouncePeerReplyMessage();
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Dict> getResponse();
+  virtual std::shared_ptr<Dict> getResponse() CXX11_OVERRIDE;
 
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
-  virtual void accept(DHTMessageCallback* callback);
+  virtual void accept(DHTMessageCallback* callback) CXX11_OVERRIDE;
 
   static const std::string ANNOUNCE_PEER;
 };
diff --git a/src/DHTAutoSaveCommand.h b/src/DHTAutoSaveCommand.h
index b1db5354..9f6111f4 100644
--- a/src/DHTAutoSaveCommand.h
+++ b/src/DHTAutoSaveCommand.h
@@ -60,9 +60,9 @@ public:
 
   virtual ~DHTAutoSaveCommand();
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 
   void setLocalNode(const std::shared_ptr<DHTNode>& localNode);
 
diff --git a/src/DHTBucketRefreshCommand.h b/src/DHTBucketRefreshCommand.h
index ac1f1274..2d9f5ca2 100644
--- a/src/DHTBucketRefreshCommand.h
+++ b/src/DHTBucketRefreshCommand.h
@@ -57,9 +57,9 @@ public:
 
   virtual ~DHTBucketRefreshCommand();
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 
   void setRoutingTable(DHTRoutingTable* routingTable);
 
diff --git a/src/DHTBucketRefreshTask.h b/src/DHTBucketRefreshTask.h
index 06bf6507..31c04866 100644
--- a/src/DHTBucketRefreshTask.h
+++ b/src/DHTBucketRefreshTask.h
@@ -48,7 +48,7 @@ public:
 
   virtual ~DHTBucketRefreshTask();
 
-  virtual void startup();
+  virtual void startup() CXX11_OVERRIDE;
 
   void setForceRefresh(bool forceRefresh);
 };
diff --git a/src/DHTConnectionImpl.h b/src/DHTConnectionImpl.h
index 8409f053..81cbac1e 100644
--- a/src/DHTConnectionImpl.h
+++ b/src/DHTConnectionImpl.h
@@ -77,10 +77,12 @@ public:
   bool bind(uint16_t& port, const std::string& addr);
 
   virtual ssize_t receiveMessage(unsigned char* data, size_t len,
-                                 std::string& host, uint16_t& port);
+                                 std::string& host, uint16_t& port)
+    CXX11_OVERRIDE;
 
   virtual ssize_t sendMessage(const unsigned char* data, size_t len,
-                              const std::string& host, uint16_t port);
+                              const std::string& host, uint16_t port)
+    CXX11_OVERRIDE;
 
   const std::shared_ptr<SocketCore>& getSocket() const
   {
diff --git a/src/DHTEntryPointNameResolveCommand.h b/src/DHTEntryPointNameResolveCommand.h
index 8ca60a1b..1ca153d3 100644
--- a/src/DHTEntryPointNameResolveCommand.h
+++ b/src/DHTEntryPointNameResolveCommand.h
@@ -90,7 +90,7 @@ public:
 
   virtual ~DHTEntryPointNameResolveCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void setBootstrapEnabled(bool f);
 
diff --git a/src/DHTFindNodeMessage.h b/src/DHTFindNodeMessage.h
index ca3017c5..4101b74b 100644
--- a/src/DHTFindNodeMessage.h
+++ b/src/DHTFindNodeMessage.h
@@ -44,18 +44,18 @@ class DHTFindNodeMessage:public DHTQueryMessage {
 private:
   unsigned char targetNodeID_[DHT_ID_LENGTH];
 protected:
-  virtual std::string toStringOptional() const;
+  virtual std::string toStringOptional() const CXX11_OVERRIDE;
 public:
   DHTFindNodeMessage(const std::shared_ptr<DHTNode>& localNode,
                      const std::shared_ptr<DHTNode>& remoteNode,
                      const unsigned char* targetNodeID,
                      const std::string& transactionID = A2STR::NIL);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Dict> getArgument();
+  virtual std::shared_ptr<Dict> getArgument() CXX11_OVERRIDE;
 
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
   const unsigned char* getTargetNodeID() const
   {
diff --git a/src/DHTFindNodeReplyMessage.h b/src/DHTFindNodeReplyMessage.h
index 3d344e48..7f0b57b2 100644
--- a/src/DHTFindNodeReplyMessage.h
+++ b/src/DHTFindNodeReplyMessage.h
@@ -46,20 +46,20 @@ private:
 
   std::vector<std::shared_ptr<DHTNode>> closestKNodes_;
 protected:
-  virtual std::string toStringOptional() const;
+  virtual std::string toStringOptional() const CXX11_OVERRIDE;
 public:
   DHTFindNodeReplyMessage(int family,
                           const std::shared_ptr<DHTNode>& localNode,
                           const std::shared_ptr<DHTNode>& remoteNode,
                           const std::string& transactionID);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Dict> getResponse();
+  virtual std::shared_ptr<Dict> getResponse() CXX11_OVERRIDE;
 
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
-  virtual void accept(DHTMessageCallback* callback);
+  virtual void accept(DHTMessageCallback* callback) CXX11_OVERRIDE;
 
   const std::vector<std::shared_ptr<DHTNode>>& getClosestKNodes() const
   {
diff --git a/src/DHTGetPeersCommand.h b/src/DHTGetPeersCommand.h
index f6e81517..44d6873f 100644
--- a/src/DHTGetPeersCommand.h
+++ b/src/DHTGetPeersCommand.h
@@ -77,7 +77,7 @@ public:
 
   virtual ~DHTGetPeersCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void setTaskQueue(DHTTaskQueue* taskQueue);
 
diff --git a/src/DHTGetPeersMessage.h b/src/DHTGetPeersMessage.h
index c0303bb7..66fce078 100644
--- a/src/DHTGetPeersMessage.h
+++ b/src/DHTGetPeersMessage.h
@@ -52,18 +52,18 @@ private:
 
   DHTTokenTracker* tokenTracker_;
 protected:
-  virtual std::string toStringOptional() const;
+  virtual std::string toStringOptional() const CXX11_OVERRIDE;
 public:
   DHTGetPeersMessage(const std::shared_ptr<DHTNode>& localNode,
                      const std::shared_ptr<DHTNode>& remoteNode,
                      const unsigned char* infoHash,
                      const std::string& transactionID = A2STR::NIL);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Dict> getArgument();
+  virtual std::shared_ptr<Dict> getArgument() CXX11_OVERRIDE;
 
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
   const unsigned char* getInfoHash() const
   {
diff --git a/src/DHTGetPeersReplyMessage.h b/src/DHTGetPeersReplyMessage.h
index 8b2b8a79..3b2c5a99 100644
--- a/src/DHTGetPeersReplyMessage.h
+++ b/src/DHTGetPeersReplyMessage.h
@@ -55,7 +55,7 @@ private:
 
   std::vector<std::shared_ptr<Peer>> values_;
 protected:
-  virtual std::string toStringOptional() const;
+  virtual std::string toStringOptional() const CXX11_OVERRIDE;
 public:
   DHTGetPeersReplyMessage(int family,
                           const std::shared_ptr<DHTNode>& localNode,
@@ -63,13 +63,13 @@ public:
                           const std::string& token,
                           const std::string& transactionID);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Dict> getResponse();
+  virtual std::shared_ptr<Dict> getResponse() CXX11_OVERRIDE;
 
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
-  virtual void accept(DHTMessageCallback* callback);
+  virtual void accept(DHTMessageCallback* callback) CXX11_OVERRIDE;
 
   const std::vector<std::shared_ptr<DHTNode>>& getClosestKNodes() const
   {
diff --git a/src/DHTInteractionCommand.h b/src/DHTInteractionCommand.h
index 38ba98a6..c53c4084 100644
--- a/src/DHTInteractionCommand.h
+++ b/src/DHTInteractionCommand.h
@@ -63,7 +63,7 @@ public:
 
   virtual ~DHTInteractionCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void setReadCheckSocket(const std::shared_ptr<SocketCore>& socket);
 
diff --git a/src/DHTMessageDispatcherImpl.h b/src/DHTMessageDispatcherImpl.h
index 744a6bb7..e2d0e72c 100644
--- a/src/DHTMessageDispatcherImpl.h
+++ b/src/DHTMessageDispatcherImpl.h
@@ -59,16 +59,18 @@ public:
   addMessageToQueue(std::unique_ptr<DHTMessage> message,
                     time_t timeout,
                     std::unique_ptr<DHTMessageCallback> callback =
-                    std::unique_ptr<DHTMessageCallback>{});
+                    std::unique_ptr<DHTMessageCallback>{})
+    CXX11_OVERRIDE;
 
   virtual void
   addMessageToQueue(std::unique_ptr<DHTMessage> message,
                     std::unique_ptr<DHTMessageCallback> callback =
-                    std::unique_ptr<DHTMessageCallback>{});
+                    std::unique_ptr<DHTMessageCallback>{})
+    CXX11_OVERRIDE;
 
-  virtual void sendMessages();
+  virtual void sendMessages() CXX11_OVERRIDE;
 
-  virtual size_t countMessageInQueue() const;
+  virtual size_t countMessageInQueue() const CXX11_OVERRIDE;
 
   void setTimeout(time_t timeout)
   {
diff --git a/src/DHTMessageFactoryImpl.h b/src/DHTMessageFactoryImpl.h
index ced2b511..a49e4bc3 100644
--- a/src/DHTMessageFactoryImpl.h
+++ b/src/DHTMessageFactoryImpl.h
@@ -83,43 +83,47 @@ public:
 
   virtual std::unique_ptr<DHTQueryMessage>
   createQueryMessage(const Dict* dict,
-                     const std::string& ipaddr, uint16_t port);
+                     const std::string& ipaddr, uint16_t port) CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTResponseMessage>
   createResponseMessage(const std::string& messageType,
                         const Dict* dict,
-                        const std::string& ipaddr, uint16_t port);
+                        const std::string& ipaddr, uint16_t port)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTPingMessage>
   createPingMessage(const std::shared_ptr<DHTNode>& remoteNode,
-                    const std::string& transactionID = A2STR::NIL);
+                    const std::string& transactionID = A2STR::NIL)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTPingReplyMessage>
   createPingReplyMessage(const std::shared_ptr<DHTNode>& remoteNode,
                          const unsigned char* id,
-                         const std::string& transactionID);
+                         const std::string& transactionID)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTFindNodeMessage>
   createFindNodeMessage(const std::shared_ptr<DHTNode>& remoteNode,
                         const unsigned char* targetNodeID,
-                        const std::string& transactionID = A2STR::NIL);
+                        const std::string& transactionID = A2STR::NIL)
+    CXX11_OVERRIDE;
 
   std::unique_ptr<DHTFindNodeReplyMessage>
   createFindNodeReplyMessage(const std::shared_ptr<DHTNode>& remoteNode,
                              const Dict* dict,
                              const std::string& transactionID);
 
-
   virtual std::unique_ptr<DHTFindNodeReplyMessage>
   createFindNodeReplyMessage
   (const std::shared_ptr<DHTNode>& remoteNode,
    std::vector<std::shared_ptr<DHTNode>> closestKNodes,
-   const std::string& transactionID);
+   const std::string& transactionID) CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTGetPeersMessage>
   createGetPeersMessage(const std::shared_ptr<DHTNode>& remoteNode,
                         const unsigned char* infoHash,
-                        const std::string& transactionID = A2STR::NIL);
+                        const std::string& transactionID = A2STR::NIL)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTGetPeersReplyMessage>
   createGetPeersReplyMessage
@@ -127,7 +131,7 @@ public:
    std::vector<std::shared_ptr<DHTNode>> closestKNodes,
    std::vector<std::shared_ptr<Peer>> peers,
    const std::string& token,
-   const std::string& transactionID);
+   const std::string& transactionID) CXX11_OVERRIDE;
 
   std::unique_ptr<DHTGetPeersReplyMessage>
   createGetPeersReplyMessage
@@ -140,15 +144,18 @@ public:
                             const unsigned char* infoHash,
                             uint16_t tcpPort,
                             const std::string& token,
-                            const std::string& transactionID = A2STR::NIL);
+                            const std::string& transactionID = A2STR::NIL)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTAnnouncePeerReplyMessage>
   createAnnouncePeerReplyMessage(const std::shared_ptr<DHTNode>& remoteNode,
-                                 const std::string& transactionID);
+                                 const std::string& transactionID)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTUnknownMessage>
   createUnknownMessage(const unsigned char* data, size_t length,
-                       const std::string& ipaddr, uint16_t port);
+                       const std::string& ipaddr, uint16_t port)
+    CXX11_OVERRIDE;
 
   void setRoutingTable(DHTRoutingTable* routingTable);
 
diff --git a/src/DHTNodeLookupTask.h b/src/DHTNodeLookupTask.h
index 59b7cab1..077fc8ad 100644
--- a/src/DHTNodeLookupTask.h
+++ b/src/DHTNodeLookupTask.h
@@ -48,12 +48,12 @@ public:
 
   virtual void getNodesFromMessage
   (std::vector<std::shared_ptr<DHTNode> >& nodes,
-   const DHTFindNodeReplyMessage* message);
+   const DHTFindNodeReplyMessage* message) CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTMessage> createMessage
-  (const std::shared_ptr<DHTNode>& remoteNode);
+  (const std::shared_ptr<DHTNode>& remoteNode) CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<DHTMessageCallback> createCallback();
+  virtual std::unique_ptr<DHTMessageCallback> createCallback() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DHTNodeLookupTaskCallback.h b/src/DHTNodeLookupTaskCallback.h
index 441ddce7..806f401d 100644
--- a/src/DHTNodeLookupTaskCallback.h
+++ b/src/DHTNodeLookupTaskCallback.h
@@ -47,15 +47,17 @@ private:
 public:
   DHTNodeLookupTaskCallback(DHTNodeLookupTask* task);
 
-  virtual void visit(const DHTAnnouncePeerReplyMessage* message);
+  virtual void visit(const DHTAnnouncePeerReplyMessage* message)
+    CXX11_OVERRIDE;
 
-  virtual void visit(const DHTFindNodeReplyMessage* message);
+  virtual void visit(const DHTFindNodeReplyMessage* message) CXX11_OVERRIDE;
 
-  virtual void visit(const DHTGetPeersReplyMessage* message);
+  virtual void visit(const DHTGetPeersReplyMessage* message) CXX11_OVERRIDE;
 
-  virtual void visit(const DHTPingReplyMessage* message);
+  virtual void visit(const DHTPingReplyMessage* message) CXX11_OVERRIDE;
 
-  virtual void onTimeout(const std::shared_ptr<DHTNode>& remoteNode);
+  virtual void onTimeout(const std::shared_ptr<DHTNode>& remoteNode)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DHTPeerAnnounceCommand.h b/src/DHTPeerAnnounceCommand.h
index 9436c932..8be4d7bf 100644
--- a/src/DHTPeerAnnounceCommand.h
+++ b/src/DHTPeerAnnounceCommand.h
@@ -51,9 +51,9 @@ public:
 
   virtual ~DHTPeerAnnounceCommand();
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 
   void setPeerAnnounceStorage(DHTPeerAnnounceStorage* storage);
 };
diff --git a/src/DHTPeerLookupTask.h b/src/DHTPeerLookupTask.h
index fdc67207..c2292245 100644
--- a/src/DHTPeerLookupTask.h
+++ b/src/DHTPeerLookupTask.h
@@ -59,16 +59,18 @@ public:
 
   virtual void getNodesFromMessage
   (std::vector<std::shared_ptr<DHTNode>>& nodes,
-   const DHTGetPeersReplyMessage* message);
+   const DHTGetPeersReplyMessage* message) CXX11_OVERRIDE;
 
-  virtual void onReceivedInternal(const DHTGetPeersReplyMessage* message);
+  virtual void onReceivedInternal(const DHTGetPeersReplyMessage* message)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<DHTMessage> createMessage
-  (const std::shared_ptr<DHTNode>& remoteNode);
+  (const std::shared_ptr<DHTNode>& remoteNode) CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<DHTMessageCallback> createCallback();
+  virtual std::unique_ptr<DHTMessageCallback> createCallback()
+    CXX11_OVERRIDE;
 
-  virtual void onFinish();
+  virtual void onFinish() CXX11_OVERRIDE;
 
   void setPeerStorage(const std::shared_ptr<PeerStorage>& peerStorage);
 };
diff --git a/src/DHTPeerLookupTaskCallback.h b/src/DHTPeerLookupTaskCallback.h
index 78cdc924..9a2f3a0e 100644
--- a/src/DHTPeerLookupTaskCallback.h
+++ b/src/DHTPeerLookupTaskCallback.h
@@ -47,15 +47,20 @@ private:
 public:
   DHTPeerLookupTaskCallback(DHTPeerLookupTask* task);
 
-  virtual void visit(const DHTAnnouncePeerReplyMessage* message);
+  virtual void visit(const DHTAnnouncePeerReplyMessage* message)
+    CXX11_OVERRIDE;
 
-  virtual void visit(const DHTFindNodeReplyMessage* message);
+  virtual void visit(const DHTFindNodeReplyMessage* message)
+    CXX11_OVERRIDE;
 
-  virtual void visit(const DHTGetPeersReplyMessage* message);
+  virtual void visit(const DHTGetPeersReplyMessage* message)
+    CXX11_OVERRIDE;
 
-  virtual void visit(const DHTPingReplyMessage* message);
+  virtual void visit(const DHTPingReplyMessage* message)
+    CXX11_OVERRIDE;
 
-  virtual void onTimeout(const std::shared_ptr<DHTNode>& remoteNode);
+  virtual void onTimeout(const std::shared_ptr<DHTNode>& remoteNode)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DHTPingMessage.h b/src/DHTPingMessage.h
index a4f47538..b5be6b3d 100644
--- a/src/DHTPingMessage.h
+++ b/src/DHTPingMessage.h
@@ -46,11 +46,11 @@ public:
                  const std::shared_ptr<DHTNode>& remoteNode,
                  const std::string& transactionID = A2STR::NIL);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Dict> getArgument();
+  virtual std::shared_ptr<Dict> getArgument() CXX11_OVERRIDE;
 
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
   static const std::string PING;
 };
diff --git a/src/DHTPingReplyMessage.h b/src/DHTPingReplyMessage.h
index a053ca4d..71494e94 100644
--- a/src/DHTPingReplyMessage.h
+++ b/src/DHTPingReplyMessage.h
@@ -49,13 +49,13 @@ public:
                       const unsigned char* id,
                       const std::string& transactionID);
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Dict> getResponse();
+  virtual std::shared_ptr<Dict> getResponse() CXX11_OVERRIDE;
 
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
-  virtual void accept(DHTMessageCallback* callback);
+  virtual void accept(DHTMessageCallback* callback) CXX11_OVERRIDE;
 
   const unsigned char* getRemoteID()
   {
diff --git a/src/DHTPingReplyMessageCallback.h b/src/DHTPingReplyMessageCallback.h
index ddb311f3..1b00c500 100644
--- a/src/DHTPingReplyMessageCallback.h
+++ b/src/DHTPingReplyMessageCallback.h
@@ -50,27 +50,28 @@ private:
 public:
   DHTPingReplyMessageCallback(Task* task):task_(task) {}
 
-  virtual void visit(const DHTAnnouncePeerReplyMessage* message)
+  virtual void visit(const DHTAnnouncePeerReplyMessage* message) CXX11_OVERRIDE
   {
     onTimeout(message->getRemoteNode());
   }
 
-  virtual void visit(const DHTFindNodeReplyMessage* message)
+  virtual void visit(const DHTFindNodeReplyMessage* message) CXX11_OVERRIDE
   {
     onTimeout(message->getRemoteNode());
   }
 
-  virtual void visit(const DHTGetPeersReplyMessage* message)
+  virtual void visit(const DHTGetPeersReplyMessage* message) CXX11_OVERRIDE
   {
     onTimeout(message->getRemoteNode());
   }
 
-  virtual void visit(const DHTPingReplyMessage* message)
+  virtual void visit(const DHTPingReplyMessage* message) CXX11_OVERRIDE
   {
     task_->onReceived(message);
   }
 
   virtual void onTimeout(const std::shared_ptr<DHTNode>& remoteNode)
+    CXX11_OVERRIDE
   {
     task_->onTimeout(remoteNode);
   }
diff --git a/src/DHTPingTask.h b/src/DHTPingTask.h
index db20b3c1..17b35940 100644
--- a/src/DHTPingTask.h
+++ b/src/DHTPingTask.h
@@ -60,7 +60,7 @@ public:
 
   virtual ~DHTPingTask();
 
-  virtual void startup();
+  virtual void startup() CXX11_OVERRIDE;
 
   void onReceived(const DHTPingReplyMessage* message);
 
diff --git a/src/DHTQueryMessage.h b/src/DHTQueryMessage.h
index 68996e91..e85067a1 100644
--- a/src/DHTQueryMessage.h
+++ b/src/DHTQueryMessage.h
@@ -51,15 +51,15 @@ public:
 
   virtual ~DHTQueryMessage();
 
-  virtual const std::string& getType() const;
+  virtual const std::string& getType() const CXX11_OVERRIDE;
 
-  virtual void fillMessage(Dict* msgDict);
+  virtual void fillMessage(Dict* msgDict) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<Dict> getArgument() = 0;
 
-  virtual bool isReply() const;
+  virtual bool isReply() const CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
   static const std::string Q;
 
diff --git a/src/DHTReplaceNodeTask.h b/src/DHTReplaceNodeTask.h
index f934bd1e..78cb9144 100644
--- a/src/DHTReplaceNodeTask.h
+++ b/src/DHTReplaceNodeTask.h
@@ -60,7 +60,7 @@ public:
 
   virtual ~DHTReplaceNodeTask();
 
-  virtual void startup();
+  virtual void startup() CXX11_OVERRIDE;
 
   void onReceived(const DHTPingReplyMessage* message);
 
diff --git a/src/DHTResponseMessage.h b/src/DHTResponseMessage.h
index f5bbe937..495fff2c 100644
--- a/src/DHTResponseMessage.h
+++ b/src/DHTResponseMessage.h
@@ -53,15 +53,15 @@ public:
 
   virtual ~DHTResponseMessage();
 
-  virtual const std::string& getType() const;
+  virtual const std::string& getType() const CXX11_OVERRIDE;
 
-  virtual void fillMessage(Dict* msgDict);
+  virtual void fillMessage(Dict* msgDict) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<Dict> getResponse() = 0;
 
-  virtual bool isReply() const;
+  virtual bool isReply() const CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
   virtual void accept(DHTMessageCallback* callback) = 0;
 
diff --git a/src/DHTTaskFactoryImpl.h b/src/DHTTaskFactoryImpl.h
index baded49d..53ff57e1 100644
--- a/src/DHTTaskFactoryImpl.h
+++ b/src/DHTTaskFactoryImpl.h
@@ -69,24 +69,26 @@ public:
 
   virtual std::shared_ptr<DHTTask>
   createPingTask(const std::shared_ptr<DHTNode>& remoteNode,
-                 int numRetry = 0);
+                 int numRetry = 0) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<DHTTask>
-  createNodeLookupTask(const unsigned char* targetID);
+  createNodeLookupTask(const unsigned char* targetID) CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<DHTTask> createBucketRefreshTask();
+  virtual std::shared_ptr<DHTTask> createBucketRefreshTask() CXX11_OVERRIDE;
 
   virtual std::shared_ptr<DHTTask>
   createPeerLookupTask(const std::shared_ptr<DownloadContext>& ctx,
                        uint16_t tcpPort,
-                       const std::shared_ptr<PeerStorage>& peerStorage);
+                       const std::shared_ptr<PeerStorage>& peerStorage)
+    CXX11_OVERRIDE;
 
   virtual std::shared_ptr<DHTTask>
-  createPeerAnnounceTask(const unsigned char* infoHash);
+  createPeerAnnounceTask(const unsigned char* infoHash) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<DHTTask>
   createReplaceNodeTask(const std::shared_ptr<DHTBucket>& bucket,
-                        const std::shared_ptr<DHTNode>& newNode);
+                        const std::shared_ptr<DHTNode>& newNode)
+    CXX11_OVERRIDE;
 
   void setRoutingTable(DHTRoutingTable* routingTable);
 
diff --git a/src/DHTTaskQueueImpl.h b/src/DHTTaskQueueImpl.h
index eb21e620..b7655ffc 100644
--- a/src/DHTTaskQueueImpl.h
+++ b/src/DHTTaskQueueImpl.h
@@ -52,13 +52,16 @@ public:
 
   virtual ~DHTTaskQueueImpl();
 
-  virtual void executeTask();
+  virtual void executeTask() CXX11_OVERRIDE;
 
-  virtual void addPeriodicTask1(const std::shared_ptr<DHTTask>& task);
+  virtual void addPeriodicTask1(const std::shared_ptr<DHTTask>& task)
+    CXX11_OVERRIDE;
 
-  virtual void addPeriodicTask2(const std::shared_ptr<DHTTask>& task);
+  virtual void addPeriodicTask2(const std::shared_ptr<DHTTask>& task)
+    CXX11_OVERRIDE;
 
-  virtual void addImmediateTask(const std::shared_ptr<DHTTask>& task);
+  virtual void addImmediateTask(const std::shared_ptr<DHTTask>& task)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DHTTokenUpdateCommand.h b/src/DHTTokenUpdateCommand.h
index be81a5e4..b273db3e 100644
--- a/src/DHTTokenUpdateCommand.h
+++ b/src/DHTTokenUpdateCommand.h
@@ -51,9 +51,9 @@ public:
 
   virtual ~DHTTokenUpdateCommand();
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 
   void setTokenTracker(DHTTokenTracker* tokenTracker);
 };
diff --git a/src/DHTUnknownMessage.h b/src/DHTUnknownMessage.h
index 2ad03cbb..0c2e4a88 100644
--- a/src/DHTUnknownMessage.h
+++ b/src/DHTUnknownMessage.h
@@ -54,19 +54,19 @@ public:
   virtual ~DHTUnknownMessage();
 
   // do nothing
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
   // do nothing; we don't use this message as outgoing message.
-  virtual bool send();
+  virtual bool send() CXX11_OVERRIDE;
 
   // always return false
-  virtual bool isReply() const;
+  virtual bool isReply() const CXX11_OVERRIDE;
 
   // returns "unknown"
-  virtual const std::string& getMessageType() const;
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE;
 
   // show some sample bytes
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
   static const std::string E;
 
diff --git a/src/DefaultAuthResolver.h b/src/DefaultAuthResolver.h
index ea2bcf61..7716b7d3 100644
--- a/src/DefaultAuthResolver.h
+++ b/src/DefaultAuthResolver.h
@@ -42,7 +42,7 @@ namespace aria2 {
 class DefaultAuthResolver : public AbstractAuthResolver {
 public:
   virtual std::unique_ptr<AuthConfig> resolveAuthConfig
-  (const std::string& hostname);
+  (const std::string& hostname) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DefaultBtAnnounce.h b/src/DefaultBtAnnounce.h
index e4141a84..067b365e 100644
--- a/src/DefaultBtAnnounce.h
+++ b/src/DefaultBtAnnounce.h
@@ -100,37 +100,38 @@ public:
 
   bool isCompletedAnnounceReady();
 
-  virtual bool isAnnounceReady();
+  virtual bool isAnnounceReady() CXX11_OVERRIDE;
 
-  virtual std::string getAnnounceUrl();
+  virtual std::string getAnnounceUrl() CXX11_OVERRIDE;
 
   virtual std::shared_ptr<UDPTrackerRequest>
   createUDPTrackerRequest(const std::string& remoteAddr, uint16_t remotePort,
-                          uint16_t localPort);
+                          uint16_t localPort) CXX11_OVERRIDE;
 
-  virtual void announceStart();
+  virtual void announceStart() CXX11_OVERRIDE;
 
-  virtual void announceSuccess();
+  virtual void announceSuccess() CXX11_OVERRIDE;
 
-  virtual void announceFailure();
+  virtual void announceFailure() CXX11_OVERRIDE;
 
-  virtual bool isAllAnnounceFailed();
+  virtual bool isAllAnnounceFailed() CXX11_OVERRIDE;
 
-  virtual void resetAnnounce();
+  virtual void resetAnnounce() CXX11_OVERRIDE;
 
   virtual void processAnnounceResponse(const unsigned char* trackerResponse,
-                                       size_t trackerResponseLength);
+                                       size_t trackerResponseLength)
+    CXX11_OVERRIDE;
 
   virtual void processUDPTrackerResponse
-  (const std::shared_ptr<UDPTrackerRequest>& req);
+  (const std::shared_ptr<UDPTrackerRequest>& req) CXX11_OVERRIDE;
 
-  virtual bool noMoreAnnounce();
+  virtual bool noMoreAnnounce() CXX11_OVERRIDE;
 
-  virtual void shuffleAnnounce();
+  virtual void shuffleAnnounce() CXX11_OVERRIDE;
 
-  virtual void overrideMinInterval(time_t interval);
+  virtual void overrideMinInterval(time_t interval) CXX11_OVERRIDE;
 
-  virtual void setTcpPort(uint16_t port)
+  virtual void setTcpPort(uint16_t port) CXX11_OVERRIDE
   {
     tcpPort_ = port;
   }
diff --git a/src/DefaultBtInteractive.h b/src/DefaultBtInteractive.h
index 61ce66a3..10aeb3ab 100644
--- a/src/DefaultBtInteractive.h
+++ b/src/DefaultBtInteractive.h
@@ -171,30 +171,31 @@ public:
 
   virtual ~DefaultBtInteractive();
 
-  virtual void initiateHandshake();
+  virtual void initiateHandshake() CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtHandshakeMessage> receiveHandshake
-  (bool quickReply = false);
+  (bool quickReply = false) CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtHandshakeMessage> receiveAndSendHandshake();
+  virtual std::unique_ptr<BtHandshakeMessage> receiveAndSendHandshake()
+    CXX11_OVERRIDE;
 
-  virtual void doPostHandshakeProcessing();
+  virtual void doPostHandshakeProcessing() CXX11_OVERRIDE;
 
-  virtual void doInteractionProcessing();
+  virtual void doInteractionProcessing() CXX11_OVERRIDE;
 
-  virtual void cancelAllPiece();
+  virtual void cancelAllPiece() CXX11_OVERRIDE;
 
-  virtual void sendPendingMessage();
+  virtual void sendPendingMessage() CXX11_OVERRIDE;
 
   size_t receiveMessages();
 
-  virtual size_t countPendingMessage();
+  virtual size_t countPendingMessage() CXX11_OVERRIDE;
 
-  virtual bool isSendingMessageInProgress();
+  virtual bool isSendingMessageInProgress() CXX11_OVERRIDE;
 
-  virtual size_t countReceivedMessageInIteration() const;
+  virtual size_t countReceivedMessageInIteration() const CXX11_OVERRIDE;
 
-  virtual size_t countOutstandingRequest();
+  virtual size_t countOutstandingRequest() CXX11_OVERRIDE;
 
   void setCuid(cuid_t cuid)
   {
diff --git a/src/DefaultBtMessageDispatcher.h b/src/DefaultBtMessageDispatcher.h
index 27192f6d..35afbd5b 100644
--- a/src/DefaultBtMessageDispatcher.h
+++ b/src/DefaultBtMessageDispatcher.h
@@ -72,47 +72,54 @@ public:
 
   virtual ~DefaultBtMessageDispatcher();
 
-  virtual void addMessageToQueue(std::unique_ptr<BtMessage> btMessage);
+  virtual void addMessageToQueue(std::unique_ptr<BtMessage> btMessage)
+    CXX11_OVERRIDE;
 
-  virtual void sendMessages();
+  virtual void sendMessages() CXX11_OVERRIDE;
 
   // For unit tests without PeerConnection
   void sendMessagesInternal();
 
   virtual void doCancelSendingPieceAction
-  (size_t index, int32_t begin, int32_t length);
+  (size_t index, int32_t begin, int32_t length) CXX11_OVERRIDE;
 
-  virtual void doCancelSendingPieceAction(const std::shared_ptr<Piece>& piece);
+  virtual void doCancelSendingPieceAction(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE;
 
-  virtual void doAbortOutstandingRequestAction(const std::shared_ptr<Piece>& piece);
+  virtual void doAbortOutstandingRequestAction
+  (const std::shared_ptr<Piece>& piece) CXX11_OVERRIDE;
 
-  virtual void doChokedAction();
+  virtual void doChokedAction() CXX11_OVERRIDE;
 
-  virtual void doChokingAction();
+  virtual void doChokingAction() CXX11_OVERRIDE;
 
-  virtual void checkRequestSlotAndDoNecessaryThing();
+  virtual void checkRequestSlotAndDoNecessaryThing() CXX11_OVERRIDE;
 
-  virtual bool isSendingInProgress();
+  virtual bool isSendingInProgress() CXX11_OVERRIDE;
 
-  virtual size_t countMessageInQueue() {
+  virtual size_t countMessageInQueue() CXX11_OVERRIDE
+  {
     return messageQueue_.size();
   }
 
-  virtual size_t countOutstandingRequest()
+  virtual size_t countOutstandingRequest() CXX11_OVERRIDE
   {
     return requestSlots_.size();
   }
 
-  virtual bool isOutstandingRequest(size_t index, size_t blockIndex);
+  virtual bool isOutstandingRequest(size_t index, size_t blockIndex)
+    CXX11_OVERRIDE;
 
   virtual const RequestSlot* getOutstandingRequest
-  (size_t index, int32_t begin, int32_t length);
+  (size_t index, int32_t begin, int32_t length) CXX11_OVERRIDE;
 
-  virtual void removeOutstandingRequest(const RequestSlot* slot);
+  virtual void removeOutstandingRequest(const RequestSlot* slot)
+    CXX11_OVERRIDE;
 
-  virtual void addOutstandingRequest(std::unique_ptr<RequestSlot> requestSlot);
+  virtual void addOutstandingRequest(std::unique_ptr<RequestSlot> requestSlot)
+    CXX11_OVERRIDE;
 
-  virtual size_t countOutstandingUpload();
+  virtual size_t countOutstandingUpload() CXX11_OVERRIDE;
 
   const std::deque<std::unique_ptr<BtMessage>>& getMessageQueue() const
   {
diff --git a/src/DefaultBtMessageFactory.h b/src/DefaultBtMessageFactory.h
index 761ad4a0..995a55ff 100644
--- a/src/DefaultBtMessageFactory.h
+++ b/src/DefaultBtMessageFactory.h
@@ -87,53 +87,67 @@ public:
   DefaultBtMessageFactory();
 
   virtual std::unique_ptr<BtMessage>
-  createBtMessage(const unsigned char* msg, size_t msgLength);
+  createBtMessage(const unsigned char* msg, size_t msgLength) CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtHandshakeMessage>
-  createHandshakeMessage(const unsigned char* msg, size_t msgLength);
+  createHandshakeMessage(const unsigned char* msg, size_t msgLength)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtHandshakeMessage>
   createHandshakeMessage(const unsigned char* infoHash,
-                         const unsigned char* peerId);
+                         const unsigned char* peerId) CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtRequestMessage>
   createRequestMessage(const std::shared_ptr<Piece>& piece,
-                       size_t blockIndex);
+                       size_t blockIndex) CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtCancelMessage>
-  createCancelMessage(size_t index, int32_t begin, int32_t length);
+  createCancelMessage(size_t index, int32_t begin, int32_t length)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtPieceMessage>
-  createPieceMessage(size_t index, int32_t begin, int32_t length);
+  createPieceMessage(size_t index, int32_t begin, int32_t length)
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtHaveMessage> createHaveMessage(size_t index);
+  virtual std::unique_ptr<BtHaveMessage> createHaveMessage(size_t index)
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtChokeMessage> createChokeMessage();
+  virtual std::unique_ptr<BtChokeMessage> createChokeMessage() CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtUnchokeMessage> createUnchokeMessage();
+  virtual std::unique_ptr<BtUnchokeMessage> createUnchokeMessage()
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtInterestedMessage> createInterestedMessage();
+  virtual std::unique_ptr<BtInterestedMessage> createInterestedMessage()
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtNotInterestedMessage> createNotInterestedMessage();
+  virtual std::unique_ptr<BtNotInterestedMessage> createNotInterestedMessage()
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtBitfieldMessage> createBitfieldMessage();
+  virtual std::unique_ptr<BtBitfieldMessage> createBitfieldMessage()
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtKeepAliveMessage> createKeepAliveMessage();
+  virtual std::unique_ptr<BtKeepAliveMessage> createKeepAliveMessage()
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtHaveAllMessage> createHaveAllMessage();
+  virtual std::unique_ptr<BtHaveAllMessage> createHaveAllMessage()
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtHaveNoneMessage> createHaveNoneMessage();
+  virtual std::unique_ptr<BtHaveNoneMessage> createHaveNoneMessage()
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtRejectMessage>
-  createRejectMessage(size_t index, int32_t begin, int32_t length);
+  createRejectMessage(size_t index, int32_t begin, int32_t length)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtAllowedFastMessage> createAllowedFastMessage
-  (size_t index);
+  (size_t index) CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtPortMessage> createPortMessage(uint16_t port);
+  virtual std::unique_ptr<BtPortMessage> createPortMessage(uint16_t port)
+    CXX11_OVERRIDE;
 
   virtual std::unique_ptr<BtExtendedMessage>
-  createBtExtendedMessage(std::unique_ptr<ExtensionMessage> msg);
+  createBtExtendedMessage(std::unique_ptr<ExtensionMessage> msg)
+    CXX11_OVERRIDE;
 
   void setPeer(const std::shared_ptr<Peer>& peer);
 
diff --git a/src/DefaultBtMessageReceiver.h b/src/DefaultBtMessageReceiver.h
index 4044abaa..c403b129 100644
--- a/src/DefaultBtMessageReceiver.h
+++ b/src/DefaultBtMessageReceiver.h
@@ -59,11 +59,12 @@ public:
   DefaultBtMessageReceiver();
 
   virtual std::unique_ptr<BtHandshakeMessage> receiveHandshake
-  (bool quickReply = false);
+  (bool quickReply = false) CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtHandshakeMessage> receiveAndSendHandshake();
+  virtual std::unique_ptr<BtHandshakeMessage> receiveAndSendHandshake()
+    CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<BtMessage> receiveMessage();
+  virtual std::unique_ptr<BtMessage> receiveMessage() CXX11_OVERRIDE;
 
   void setDownloadContext(DownloadContext* downloadContext);
 
diff --git a/src/DefaultBtProgressInfoFile.h b/src/DefaultBtProgressInfoFile.h
index 5c821d77..28175e47 100644
--- a/src/DefaultBtProgressInfoFile.h
+++ b/src/DefaultBtProgressInfoFile.h
@@ -66,18 +66,18 @@ public:
 
   virtual ~DefaultBtProgressInfoFile();
 
-  virtual std::string getFilename() { return filename_; }
+  virtual std::string getFilename() CXX11_OVERRIDE { return filename_; }
 
-  virtual bool exists();
+  virtual bool exists() CXX11_OVERRIDE;
 
-  virtual void save();
+  virtual void save() CXX11_OVERRIDE;
 
-  virtual void load();
+  virtual void load() CXX11_OVERRIDE;
 
-  virtual void removeFile();
+  virtual void removeFile() CXX11_OVERRIDE;
 
   // re-set filename using current dctx_.
-  virtual void updateFilename();
+  virtual void updateFilename() CXX11_OVERRIDE;
 
 #ifdef ENABLE_BITTORRENT
   // for torrents
diff --git a/src/DefaultBtRequestFactory.h b/src/DefaultBtRequestFactory.h
index a6f03a3e..ccae7252 100644
--- a/src/DefaultBtRequestFactory.h
+++ b/src/DefaultBtRequestFactory.h
@@ -65,26 +65,29 @@ public:
 
   virtual ~DefaultBtRequestFactory();
 
-  virtual void addTargetPiece(const std::shared_ptr<Piece>& piece);
+  virtual void addTargetPiece(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE;
 
-  virtual void removeTargetPiece(const std::shared_ptr<Piece>& piece);
+  virtual void removeTargetPiece(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE;
 
-  virtual void removeAllTargetPiece();
+  virtual void removeAllTargetPiece() CXX11_OVERRIDE;
 
-  virtual size_t countTargetPiece() {
+  virtual size_t countTargetPiece() CXX11_OVERRIDE
+  {
     return pieces_.size();
   }
 
-  virtual size_t countMissingBlock();
+  virtual size_t countMissingBlock() CXX11_OVERRIDE;
 
-  virtual void removeCompletedPiece();
+  virtual void removeCompletedPiece() CXX11_OVERRIDE;
 
-  virtual void doChokedAction();
+  virtual void doChokedAction() CXX11_OVERRIDE;
 
   virtual std::vector<std::unique_ptr<BtRequestMessage>> createRequestMessages
-  (size_t max, bool endGame);
+  (size_t max, bool endGame) CXX11_OVERRIDE;
 
-  virtual std::vector<size_t> getTargetPieceIndexes() const;
+  virtual std::vector<size_t> getTargetPieceIndexes() const CXX11_OVERRIDE;
 
   std::deque<std::shared_ptr<Piece> >& getTargetPieces()
   {
diff --git a/src/DefaultDiskWriter.h b/src/DefaultDiskWriter.h
index 08e49257..7ce09e09 100644
--- a/src/DefaultDiskWriter.h
+++ b/src/DefaultDiskWriter.h
@@ -45,7 +45,7 @@ public:
 
   virtual ~DefaultDiskWriter();
 
-  virtual void initAndOpenFile(int64_t totalLength = 0);
+  virtual void initAndOpenFile(int64_t totalLength = 0) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DefaultDiskWriterFactory.h b/src/DefaultDiskWriterFactory.h
index 41696a76..c89a6eb4 100644
--- a/src/DefaultDiskWriterFactory.h
+++ b/src/DefaultDiskWriterFactory.h
@@ -45,7 +45,7 @@ class DefaultDiskWriterFactory:public DiskWriterFactory
 {
 public:
   virtual std::unique_ptr<DiskWriter> newDiskWriter
-  (const std::string& filename);
+  (const std::string& filename) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DefaultExtensionMessageFactory.h b/src/DefaultExtensionMessageFactory.h
index 7be897e2..7a8e0b7b 100644
--- a/src/DefaultExtensionMessageFactory.h
+++ b/src/DefaultExtensionMessageFactory.h
@@ -69,7 +69,7 @@ public:
   (const std::shared_ptr<Peer>& peer, ExtensionMessageRegistry* registry);
 
   virtual std::unique_ptr<ExtensionMessage>
-  createMessage(const unsigned char* data, size_t length);
+  createMessage(const unsigned char* data, size_t length) CXX11_OVERRIDE;
 
   void setPeerStorage(PeerStorage* peerStorage);
 
diff --git a/src/DefaultPeerStorage.h b/src/DefaultPeerStorage.h
index 3e43d798..9f2a127d 100644
--- a/src/DefaultPeerStorage.h
+++ b/src/DefaultPeerStorage.h
@@ -84,33 +84,35 @@ public:
   virtual ~DefaultPeerStorage();
 
   // TODO We need addAndCheckoutPeer for incoming peers
-  virtual bool addPeer(const std::shared_ptr<Peer>& peer);
+  virtual bool addPeer(const std::shared_ptr<Peer>& peer) CXX11_OVERRIDE;
 
-  virtual size_t countAllPeer() const;
+  virtual size_t countAllPeer() const CXX11_OVERRIDE;
 
   std::shared_ptr<Peer> getPeer(const std::string& ipaddr, uint16_t port) const;
 
-  virtual void addPeer(const std::vector<std::shared_ptr<Peer> >& peers);
+  virtual void addPeer(const std::vector<std::shared_ptr<Peer> >& peers)
+    CXX11_OVERRIDE;
 
   const std::deque<std::shared_ptr<Peer> >& getUnusedPeers();
 
-  virtual const PeerSet& getUsedPeers();
+  virtual const PeerSet& getUsedPeers() CXX11_OVERRIDE;
 
-  virtual const std::deque<std::shared_ptr<Peer> >& getDroppedPeers();
+  virtual const std::deque<std::shared_ptr<Peer> >& getDroppedPeers()
+    CXX11_OVERRIDE;
 
-  virtual bool isPeerAvailable();
+  virtual bool isPeerAvailable() CXX11_OVERRIDE;
 
-  virtual bool isBadPeer(const std::string& ipaddr);
+  virtual bool isBadPeer(const std::string& ipaddr) CXX11_OVERRIDE;
 
-  virtual void addBadPeer(const std::string& ipaddr);
+  virtual void addBadPeer(const std::string& ipaddr) CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Peer> checkoutPeer(cuid_t cuid);
+  virtual std::shared_ptr<Peer> checkoutPeer(cuid_t cuid) CXX11_OVERRIDE;
 
-  virtual void returnPeer(const std::shared_ptr<Peer>& peer);
+  virtual void returnPeer(const std::shared_ptr<Peer>& peer) CXX11_OVERRIDE;
 
-  virtual bool chokeRoundIntervalElapsed();
+  virtual bool chokeRoundIntervalElapsed() CXX11_OVERRIDE;
 
-  virtual void executeChoke();
+  virtual void executeChoke() CXX11_OVERRIDE;
 
   void deleteUnusedPeer(size_t delSize);
 
diff --git a/src/DefaultPieceStorage.h b/src/DefaultPieceStorage.h
index e79cc1d7..5fb7aac5 100644
--- a/src/DefaultPieceStorage.h
+++ b/src/DefaultPieceStorage.h
@@ -129,42 +129,43 @@ public:
 
 #ifdef ENABLE_BITTORRENT
 
-  virtual bool hasMissingPiece(const std::shared_ptr<Peer>& peer);
+  virtual bool hasMissingPiece(const std::shared_ptr<Peer>& peer)
+    CXX11_OVERRIDE;
 
   virtual void getMissingPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual void getMissingPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual void getMissingFastPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual void getMissingFastPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<Piece> getMissingPiece
   (const std::shared_ptr<Peer>& peer,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual  std::shared_ptr<Piece> getMissingPiece
   (const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   std::shared_ptr<Piece> getMissingFastPiece
   (const std::shared_ptr<Peer>& peer,
@@ -177,52 +178,56 @@ public:
 
 #endif // ENABLE_BITTORRENT
 
-  virtual bool hasMissingUnusedPiece();
+  virtual bool hasMissingUnusedPiece() CXX11_OVERRIDE;
 
   virtual std::shared_ptr<Piece> getMissingPiece
   (size_t minSplitSize,
    const unsigned char* ignoreBitfield,
    size_t length,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Piece> getMissingPiece(size_t index, cuid_t cuid);
+  virtual std::shared_ptr<Piece> getMissingPiece(size_t index, cuid_t cuid)
+    CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Piece> getPiece(size_t index);
+  virtual std::shared_ptr<Piece> getPiece(size_t index) CXX11_OVERRIDE;
 
-  virtual void completePiece(const std::shared_ptr<Piece>& piece);
+  virtual void completePiece(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE;
 
-  virtual void cancelPiece(const std::shared_ptr<Piece>& piece, cuid_t cuid);
+  virtual void cancelPiece(const std::shared_ptr<Piece>& piece, cuid_t cuid)
+    CXX11_OVERRIDE;
 
-  virtual bool hasPiece(size_t index);
+  virtual bool hasPiece(size_t index) CXX11_OVERRIDE;
 
-  virtual bool isPieceUsed(size_t index);
+  virtual bool isPieceUsed(size_t index) CXX11_OVERRIDE;
 
-  virtual int64_t getTotalLength();
+  virtual int64_t getTotalLength() CXX11_OVERRIDE;
 
-  virtual int64_t getFilteredTotalLength();
+  virtual int64_t getFilteredTotalLength() CXX11_OVERRIDE;
 
-  virtual int64_t getCompletedLength();
+  virtual int64_t getCompletedLength() CXX11_OVERRIDE;
 
-  virtual int64_t getFilteredCompletedLength();
+  virtual int64_t getFilteredCompletedLength() CXX11_OVERRIDE;
 
-  virtual void initStorage();
+  virtual void initStorage() CXX11_OVERRIDE;
 
-  virtual void setupFileFilter();
+  virtual void setupFileFilter() CXX11_OVERRIDE;
 
-  virtual void clearFileFilter();
+  virtual void clearFileFilter() CXX11_OVERRIDE;
 
-  virtual bool downloadFinished();
+  virtual bool downloadFinished() CXX11_OVERRIDE;
 
-  virtual bool allDownloadFinished();
+  virtual bool allDownloadFinished() CXX11_OVERRIDE;
 
   virtual void setBitfield(const unsigned char* bitfield,
-                           size_t bitfieldLength);
+                           size_t bitfieldLength) CXX11_OVERRIDE;
 
-  virtual size_t getBitfieldLength();
+  virtual size_t getBitfieldLength() CXX11_OVERRIDE;
 
-  virtual const unsigned char* getBitfield();
+  virtual const unsigned char* getBitfield() CXX11_OVERRIDE;
 
-  virtual void setEndGamePieceNum(size_t num) {
+  virtual void setEndGamePieceNum(size_t num) CXX11_OVERRIDE
+  {
     endGamePieceNum_ = num;
   }
 
@@ -230,63 +235,65 @@ public:
     return endGamePieceNum_;
   }
 
-  virtual bool isSelectiveDownloadingMode();
+  virtual bool isSelectiveDownloadingMode() CXX11_OVERRIDE;
 
-  virtual bool isEndGame()
+  virtual bool isEndGame() CXX11_OVERRIDE
   {
     return endGame_;
   }
 
-  virtual void enterEndGame()
+  virtual void enterEndGame() CXX11_OVERRIDE
   {
     endGame_ = true;
   }
 
-  virtual std::shared_ptr<DiskAdaptor> getDiskAdaptor();
+  virtual std::shared_ptr<DiskAdaptor> getDiskAdaptor() CXX11_OVERRIDE;
 
-  virtual WrDiskCache* getWrDiskCache();
+  virtual WrDiskCache* getWrDiskCache() CXX11_OVERRIDE;
 
-  virtual void flushWrDiskCacheEntry();
+  virtual void flushWrDiskCacheEntry() CXX11_OVERRIDE;
 
-  virtual int32_t getPieceLength(size_t index);
+  virtual int32_t getPieceLength(size_t index) CXX11_OVERRIDE;
 
-  virtual void advertisePiece(cuid_t cuid, size_t index);
+  virtual void advertisePiece(cuid_t cuid, size_t index) CXX11_OVERRIDE;
 
   virtual void
   getAdvertisedPieceIndexes(std::vector<size_t>& indexes,
-                            cuid_t myCuid, const Timer& lastCheckTime);
+                            cuid_t myCuid, const Timer& lastCheckTime)
+    CXX11_OVERRIDE;
 
-  virtual void removeAdvertisedPiece(time_t elapsed);
+  virtual void removeAdvertisedPiece(time_t elapsed) CXX11_OVERRIDE;
 
-  virtual void markAllPiecesDone();
+  virtual void markAllPiecesDone() CXX11_OVERRIDE;
 
-  virtual void markPiecesDone(int64_t length);
+  virtual void markPiecesDone(int64_t length) CXX11_OVERRIDE;
 
-  virtual void markPieceMissing(size_t index);
+  virtual void markPieceMissing(size_t index) CXX11_OVERRIDE;
 
   virtual void addInFlightPiece
-  (const std::vector<std::shared_ptr<Piece> >& pieces);
+  (const std::vector<std::shared_ptr<Piece> >& pieces) CXX11_OVERRIDE;
 
-  virtual size_t countInFlightPiece();
+  virtual size_t countInFlightPiece() CXX11_OVERRIDE;
 
   virtual void getInFlightPieces
-  (std::vector<std::shared_ptr<Piece> >& pieces);
+  (std::vector<std::shared_ptr<Piece> >& pieces) CXX11_OVERRIDE;
 
-  virtual void addPieceStats(size_t index);
+  virtual void addPieceStats(size_t index) CXX11_OVERRIDE;
 
   virtual void addPieceStats(const unsigned char* bitfield,
-                             size_t bitfieldLength);
+                             size_t bitfieldLength) CXX11_OVERRIDE;
 
   virtual void subtractPieceStats(const unsigned char* bitfield,
-                                  size_t bitfieldLength);
+                                  size_t bitfieldLength) CXX11_OVERRIDE;
 
   virtual void updatePieceStats(const unsigned char* newBitfield,
                                 size_t newBitfieldLength,
-                                const unsigned char* oldBitfield);
+                                const unsigned char* oldBitfield)
+    CXX11_OVERRIDE;
 
-  virtual size_t getNextUsedIndex(size_t index);
+  virtual size_t getNextUsedIndex(size_t index) CXX11_OVERRIDE;
 
-  virtual void onDownloadIncomplete();
+  virtual void onDownloadIncomplete() CXX11_OVERRIDE;
 
   /**
    * This method is made private for test purpose only.
diff --git a/src/DefaultStreamPieceSelector.h b/src/DefaultStreamPieceSelector.h
index 33d72ac2..2bb38924 100644
--- a/src/DefaultStreamPieceSelector.h
+++ b/src/DefaultStreamPieceSelector.h
@@ -50,9 +50,9 @@ public:
   (size_t& index,
    size_t minSplitSize,
    const unsigned char* ignoreBitfield,
-   size_t length);
+   size_t length) CXX11_OVERRIDE;
 
-  virtual void onBitfieldInit();
+  virtual void onBitfieldInit() CXX11_OVERRIDE;
 private:
   BitfieldMan* bitfieldMan_;
 };
diff --git a/src/DirectDiskAdaptor.h b/src/DirectDiskAdaptor.h
index a46a05dd..7b49ab81 100644
--- a/src/DirectDiskAdaptor.h
+++ b/src/DirectDiskAdaptor.h
@@ -41,9 +41,9 @@ namespace aria2 {
 
 class DirectDiskAdaptor : public AbstractSingleDiskAdaptor {
 public:
-  virtual const std::string& getFilePath();
+  virtual const std::string& getFilePath() CXX11_OVERRIDE;
 
-  virtual size_t utime(const Time& actime, const Time& modtime);
+  virtual size_t utime(const Time& actime, const Time& modtime) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/DlAbortEx.h b/src/DlAbortEx.h
index e49e827d..7d147a0d 100644
--- a/src/DlAbortEx.h
+++ b/src/DlAbortEx.h
@@ -40,7 +40,7 @@ namespace aria2 {
 
 class DlAbortEx:public RecoverableException {
 protected:
-  virtual std::shared_ptr<Exception> copy() const;
+  virtual std::shared_ptr<Exception> copy() const CXX11_OVERRIDE;
 public:
   DlAbortEx(const char* file, int line, const std::string& msg);
 
diff --git a/src/DlRetryEx.h b/src/DlRetryEx.h
index 98a0ff59..42b9dd12 100644
--- a/src/DlRetryEx.h
+++ b/src/DlRetryEx.h
@@ -40,7 +40,7 @@ namespace aria2 {
 
 class DlRetryEx:public RecoverableException {
 protected:
-  virtual std::shared_ptr<Exception> copy() const;
+  virtual std::shared_ptr<Exception> copy() const CXX11_OVERRIDE;
 public:
   DlRetryEx(const char* file, int line, const std::string& msg);
 
diff --git a/src/DownloadCommand.h b/src/DownloadCommand.h
index 268c7992..02520c2c 100644
--- a/src/DownloadCommand.h
+++ b/src/DownloadCommand.h
@@ -73,7 +73,7 @@ private:
 
   bool sinkFilterOnly_;
 protected:
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 
   virtual bool prepareForNextSegment();
 
diff --git a/src/DownloadFailureException.h b/src/DownloadFailureException.h
index 2d147a34..920869e7 100644
--- a/src/DownloadFailureException.h
+++ b/src/DownloadFailureException.h
@@ -44,7 +44,7 @@ namespace aria2 {
  */
 class DownloadFailureException:public RecoverableException {
 protected:
-  virtual std::shared_ptr<Exception> copy() const;
+  virtual std::shared_ptr<Exception> copy() const CXX11_OVERRIDE;
 public:
   DownloadFailureException(const char* file, int line, const std::string& msg);
 
diff --git a/src/EpollEventPoll.h b/src/EpollEventPoll.h
index 4529dc01..83f9bdb3 100644
--- a/src/EpollEventPoll.h
+++ b/src/EpollEventPoll.h
@@ -105,19 +105,22 @@ public:
 
   virtual ~EpollEventPoll();
 
-  virtual void poll(const struct timeval& tv);
+  virtual void poll(const struct timeval& tv) CXX11_OVERRIDE;
 
   virtual bool addEvents(sock_t socket,
-                         Command* command, EventPoll::EventType events);
+                         Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 
   virtual bool deleteEvents(sock_t socket,
-                            Command* command, EventPoll::EventType events);
+                            Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 #ifdef ENABLE_ASYNC_DNS
 
   virtual bool addNameResolver(const std::shared_ptr<AsyncNameResolver>& resolver,
-                               Command* command);
+                               Command* command) CXX11_OVERRIDE;
   virtual bool deleteNameResolver
-  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command);
+  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command)
+    CXX11_OVERRIDE;
 #endif // ENABLE_ASYNC_DNS
 
   static const int IEV_READ = EPOLLIN;
diff --git a/src/FallocFileAllocationIterator.h b/src/FallocFileAllocationIterator.h
index dbe47e5d..9c7f474e 100644
--- a/src/FallocFileAllocationIterator.h
+++ b/src/FallocFileAllocationIterator.h
@@ -50,13 +50,13 @@ public:
   FallocFileAllocationIterator(BinaryStream* stream, int64_t offset,
                                int64_t totalLength);
 
-  virtual void allocateChunk();
+  virtual void allocateChunk() CXX11_OVERRIDE;
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
-  virtual int64_t getCurrentLength();
+  virtual int64_t getCurrentLength() CXX11_OVERRIDE;
 
-  virtual int64_t getTotalLength();
+  virtual int64_t getTotalLength() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/FatalException.h b/src/FatalException.h
index 8b777a25..3761f82d 100644
--- a/src/FatalException.h
+++ b/src/FatalException.h
@@ -40,7 +40,7 @@ namespace aria2 {
 
 class FatalException:public Exception {
 protected:
-  virtual std::shared_ptr<Exception> copy() const;
+  virtual std::shared_ptr<Exception> copy() const CXX11_OVERRIDE;
 public:
   FatalException(const char* file, int line, const std::string& msg);
 
diff --git a/src/FeedbackURISelector.h b/src/FeedbackURISelector.h
index dedc8f1d..34b180e8 100644
--- a/src/FeedbackURISelector.h
+++ b/src/FeedbackURISelector.h
@@ -61,7 +61,8 @@ public:
   // This function expects ignoreHosts are ordered in ascending order.
   virtual std::string select
   (FileEntry* fileEntry,
-   const std::vector<std::pair<size_t, std::string> >& usedHosts);
+   const std::vector<std::pair<size_t, std::string> >& usedHosts)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/FileAllocationCommand.h b/src/FileAllocationCommand.h
index d8f6bbf7..239b1890 100644
--- a/src/FileAllocationCommand.h
+++ b/src/FileAllocationCommand.h
@@ -56,9 +56,9 @@ public:
 
   virtual ~FileAllocationCommand();
 
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 
-  virtual bool handleException(Exception& e);
+  virtual bool handleException(Exception& e) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/FileAllocationDispatcherCommand.h b/src/FileAllocationDispatcherCommand.h
index a595632f..410b6407 100644
--- a/src/FileAllocationDispatcherCommand.h
+++ b/src/FileAllocationDispatcherCommand.h
@@ -50,7 +50,8 @@ public:
    FileAllocationMan* fileAllocMan,
    DownloadEngine* e);
 protected:
-  virtual std::unique_ptr<Command> createCommand(FileAllocationEntry* entry);
+  virtual std::unique_ptr<Command> createCommand(FileAllocationEntry* entry)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/FileAllocationEntry.h b/src/FileAllocationEntry.h
index 60893f49..69e0730b 100644
--- a/src/FileAllocationEntry.h
+++ b/src/FileAllocationEntry.h
@@ -58,11 +58,11 @@ public:
 
   ~FileAllocationEntry();
 
-  virtual int64_t getCurrentLength();
+  virtual int64_t getCurrentLength() CXX11_OVERRIDE;
 
-  virtual int64_t getTotalLength();
+  virtual int64_t getTotalLength() CXX11_OVERRIDE;
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
   void allocateChunk();
 
diff --git a/src/FillRequestGroupCommand.h b/src/FillRequestGroupCommand.h
index dba0801d..c13a076c 100644
--- a/src/FillRequestGroupCommand.h
+++ b/src/FillRequestGroupCommand.h
@@ -51,7 +51,7 @@ public:
 
   virtual ~FillRequestGroupCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/FtpDownloadCommand.h b/src/FtpDownloadCommand.h
index 77b41172..c9b1c408 100644
--- a/src/FtpDownloadCommand.h
+++ b/src/FtpDownloadCommand.h
@@ -47,8 +47,8 @@ private:
 
   std::shared_ptr<SocketCore> ctrlSocket_;
 protected:
-  virtual bool prepareForNextSegment();
-  virtual int64_t getRequestEndOffset() const;
+  virtual bool prepareForNextSegment() CXX11_OVERRIDE;
+  virtual int64_t getRequestEndOffset() const CXX11_OVERRIDE;
 public:
   FtpDownloadCommand(cuid_t cuid,
                      const std::shared_ptr<Request>& req,
diff --git a/src/FtpFinishDownloadCommand.h b/src/FtpFinishDownloadCommand.h
index fb3f1be2..bc3d5422 100644
--- a/src/FtpFinishDownloadCommand.h
+++ b/src/FtpFinishDownloadCommand.h
@@ -45,9 +45,9 @@ class FtpFinishDownloadCommand : public AbstractCommand {
 private:
   std::shared_ptr<FtpConnection> ftpConnection_;
 protected:
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 public:
   FtpFinishDownloadCommand(cuid_t cuid,
                            const std::shared_ptr<Request>& req,
diff --git a/src/FtpInitiateConnectionCommand.h b/src/FtpInitiateConnectionCommand.h
index d8c6070e..4d4f482b 100644
--- a/src/FtpInitiateConnectionCommand.h
+++ b/src/FtpInitiateConnectionCommand.h
@@ -44,7 +44,7 @@ protected:
   virtual std::unique_ptr<Command> createNextCommand
   (const std::string& hostname, const std::string& addr, uint16_t port,
    const std::vector<std::string>& resolvedAddresses,
-   const std::shared_ptr<Request>& proxyRequest);
+   const std::shared_ptr<Request>& proxyRequest) CXX11_OVERRIDE;
 public:
   FtpInitiateConnectionCommand(cuid_t cuid, const std::shared_ptr<Request>& req,
                                const std::shared_ptr<FileEntry>& fileEntry,
diff --git a/src/FtpNegotiationCommand.h b/src/FtpNegotiationCommand.h
index 9fa5ad1d..f545ec89 100644
--- a/src/FtpNegotiationCommand.h
+++ b/src/FtpNegotiationCommand.h
@@ -154,7 +154,7 @@ private:
 
   std::deque<std::string> cwdDirs_;
 protected:
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 public:
   FtpNegotiationCommand(cuid_t cuid,
                         const std::shared_ptr<Request>& req,
diff --git a/src/FtpNegotiationConnectChain.h b/src/FtpNegotiationConnectChain.h
index 65aaead7..5c6b7c20 100644
--- a/src/FtpNegotiationConnectChain.h
+++ b/src/FtpNegotiationConnectChain.h
@@ -45,7 +45,7 @@ namespace aria2 {
 struct FtpNegotiationConnectChain : public ControlChain<ConnectCommand*> {
   FtpNegotiationConnectChain() {}
   virtual ~FtpNegotiationConnectChain() {}
-  virtual int run(ConnectCommand* t, DownloadEngine* e)
+  virtual int run(ConnectCommand* t, DownloadEngine* e) CXX11_OVERRIDE
   {
     auto c = make_unique<FtpNegotiationCommand>
       (t->getCuid(),
diff --git a/src/FtpTunnelRequestCommand.h b/src/FtpTunnelRequestCommand.h
index 664abf99..66322c49 100644
--- a/src/FtpTunnelRequestCommand.h
+++ b/src/FtpTunnelRequestCommand.h
@@ -52,7 +52,7 @@ public:
                           const std::shared_ptr<SocketCore>& s);
   virtual ~FtpTunnelRequestCommand();
 
-  virtual std::unique_ptr<Command> getNextCommand();
+  virtual std::unique_ptr<Command> getNextCommand() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/FtpTunnelRequestConnectChain.h b/src/FtpTunnelRequestConnectChain.h
index ef38a753..6a48966b 100644
--- a/src/FtpTunnelRequestConnectChain.h
+++ b/src/FtpTunnelRequestConnectChain.h
@@ -45,7 +45,7 @@ namespace aria2 {
 struct FtpTunnelRequestConnectChain : public ControlChain<ConnectCommand*> {
   FtpTunnelRequestConnectChain() {}
   virtual ~FtpTunnelRequestConnectChain() {}
-  virtual int run(ConnectCommand* t, DownloadEngine* e)
+  virtual int run(ConnectCommand* t, DownloadEngine* e) CXX11_OVERRIDE
   {
     auto c = make_unique<FtpTunnelRequestCommand>
       (t->getCuid(),
diff --git a/src/FtpTunnelResponseCommand.h b/src/FtpTunnelResponseCommand.h
index 6b5fdbef..242a6a2f 100644
--- a/src/FtpTunnelResponseCommand.h
+++ b/src/FtpTunnelResponseCommand.h
@@ -52,7 +52,7 @@ public:
                            const std::shared_ptr<SocketCore>& s);
   virtual ~FtpTunnelResponseCommand();
 
-  virtual std::unique_ptr<Command> getNextCommand();
+  virtual std::unique_ptr<Command> getNextCommand() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/GZipDecodingStreamFilter.h b/src/GZipDecodingStreamFilter.h
index 1b520bc8..fca170ea 100644
--- a/src/GZipDecodingStreamFilter.h
+++ b/src/GZipDecodingStreamFilter.h
@@ -56,19 +56,20 @@ public:
 
   virtual ~GZipDecodingStreamFilter();
 
-  virtual void init();
+  virtual void init() CXX11_OVERRIDE;
 
   virtual ssize_t transform(const std::shared_ptr<BinaryStream>& out,
                             const std::shared_ptr<Segment>& segment,
-                            const unsigned char* inbuf, size_t inlen);
+                            const unsigned char* inbuf, size_t inlen)
+    CXX11_OVERRIDE;
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
-  virtual void release();
+  virtual void release() CXX11_OVERRIDE;
 
-  virtual const std::string& getName() const;
+  virtual const std::string& getName() const CXX11_OVERRIDE;
 
-  virtual size_t getBytesProcessed() const
+  virtual size_t getBytesProcessed() const CXX11_OVERRIDE
   {
     return bytesProcessed_;
   }
diff --git a/src/GZipFile.h b/src/GZipFile.h
index 73a3182d..4a2eb043 100644
--- a/src/GZipFile.h
+++ b/src/GZipFile.h
@@ -47,16 +47,16 @@ public:
   GZipFile(const char* filename, const char* mode);
   virtual ~GZipFile();
 protected:
-  virtual size_t onRead(void* ptr, size_t count);
-  virtual size_t onWrite(const void* ptr, size_t count);
-  virtual char* onGets(char* s, int size);
-  virtual int onVprintf(const char* format, va_list va);
-  virtual int onFlush();
-  virtual int onClose();
-  virtual bool onSupportsColor();
-  virtual bool isError() const;
-  virtual bool isEOF() const;
-  virtual bool isOpen() const;
+  virtual size_t onRead(void* ptr, size_t count) CXX11_OVERRIDE;
+  virtual size_t onWrite(const void* ptr, size_t count) CXX11_OVERRIDE;
+  virtual char* onGets(char* s, int size) CXX11_OVERRIDE;
+  virtual int onVprintf(const char* format, va_list va) CXX11_OVERRIDE;
+  virtual int onFlush() CXX11_OVERRIDE;
+  virtual int onClose() CXX11_OVERRIDE;
+  virtual bool onSupportsColor() CXX11_OVERRIDE;
+  virtual bool isError() const CXX11_OVERRIDE;
+  virtual bool isEOF() const CXX11_OVERRIDE;
+  virtual bool isOpen() const CXX11_OVERRIDE;
 private:
   // Don't allow copying
   GZipFile(const GZipFile&);
diff --git a/src/GeomStreamPieceSelector.h b/src/GeomStreamPieceSelector.h
index 2c234742..d3aa3d68 100644
--- a/src/GeomStreamPieceSelector.h
+++ b/src/GeomStreamPieceSelector.h
@@ -50,9 +50,9 @@ public:
   (size_t& index,
    size_t minSplitSize,
    const unsigned char* ignoreBitfield,
-   size_t length);
+   size_t length) CXX11_OVERRIDE;
 
-  virtual void onBitfieldInit();
+  virtual void onBitfieldInit() CXX11_OVERRIDE;
 private:
   BitfieldMan* bitfieldMan_;
   double base_;
diff --git a/src/GrowSegment.h b/src/GrowSegment.h
index b16c0f56..8ca96af7 100644
--- a/src/GrowSegment.h
+++ b/src/GrowSegment.h
@@ -48,65 +48,65 @@ public:
 
   virtual ~GrowSegment();
 
-  virtual bool complete() const
+  virtual bool complete() const CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual size_t getIndex() const
+  virtual size_t getIndex() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int64_t getPosition() const
+  virtual int64_t getPosition() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int64_t getPositionToWrite() const
+  virtual int64_t getPositionToWrite() const CXX11_OVERRIDE
   {
     return writtenLength_;
   }
 
-  virtual int32_t getLength() const
+  virtual int32_t getLength() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int32_t getSegmentLength() const
+  virtual int32_t getSegmentLength() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int32_t getWrittenLength() const
+  virtual int32_t getWrittenLength() const CXX11_OVERRIDE
   {
     return writtenLength_;
   }
 
-  virtual void updateWrittenLength(int32_t bytes);
+  virtual void updateWrittenLength(int32_t bytes) CXX11_OVERRIDE;
 
 #ifdef ENABLE_MESSAGE_DIGEST
 
   virtual bool updateHash
   (int32_t begin,
    const unsigned char* data,
-   size_t dataLength)
+   size_t dataLength) CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual bool isHashCalculated() const
+  virtual bool isHashCalculated() const CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual std::string getDigest();
+  virtual std::string getDigest() CXX11_OVERRIDE;
 
 #endif // ENABLE_MESSAGE_DIGEST
 
-  virtual void clear(WrDiskCache* diskCache);
+  virtual void clear(WrDiskCache* diskCache) CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Piece> getPiece() const;
+  virtual std::shared_ptr<Piece> getPiece() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/HandshakeExtensionMessage.h b/src/HandshakeExtensionMessage.h
index 33821dcf..1a7e48a0 100644
--- a/src/HandshakeExtensionMessage.h
+++ b/src/HandshakeExtensionMessage.h
@@ -65,21 +65,21 @@ public:
 
   virtual std::string getPayload();
 
-  virtual uint8_t getExtensionMessageID() const
+  virtual uint8_t getExtensionMessageID() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual const char* getExtensionName() const
+  virtual const char* getExtensionName() const CXX11_OVERRIDE
   {
     return EXTENSION_NAME;
   }
 
   static const char EXTENSION_NAME[];
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
   void setClientVersion(const std::string& version)
   {
diff --git a/src/HaveEraseCommand.h b/src/HaveEraseCommand.h
index d08ced91..0c7c5699 100644
--- a/src/HaveEraseCommand.h
+++ b/src/HaveEraseCommand.h
@@ -46,9 +46,9 @@ public:
 
   virtual ~HaveEraseCommand();
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/HttpDownloadCommand.h b/src/HttpDownloadCommand.h
index fedcd065..b8e70cd2 100644
--- a/src/HttpDownloadCommand.h
+++ b/src/HttpDownloadCommand.h
@@ -47,8 +47,8 @@ private:
   std::unique_ptr<HttpResponse> httpResponse_;
   std::shared_ptr<HttpConnection> httpConnection_;
 protected:
-  virtual bool prepareForNextSegment();
-  virtual int64_t getRequestEndOffset() const;
+  virtual bool prepareForNextSegment() CXX11_OVERRIDE;
+  virtual int64_t getRequestEndOffset() const CXX11_OVERRIDE;
 public:
   HttpDownloadCommand(cuid_t cuid,
                       const std::shared_ptr<Request>& req,
diff --git a/src/HttpInitiateConnectionCommand.h b/src/HttpInitiateConnectionCommand.h
index 176ae4b4..df4e6fa1 100644
--- a/src/HttpInitiateConnectionCommand.h
+++ b/src/HttpInitiateConnectionCommand.h
@@ -71,7 +71,7 @@ protected:
   virtual std::unique_ptr<Command> createNextCommand
   (const std::string& hostname, const std::string& addr, uint16_t port,
    const std::vector<std::string>& resolvedAddresses,
-   const std::shared_ptr<Request>& proxyRequest);
+   const std::shared_ptr<Request>& proxyRequest) CXX11_OVERRIDE;
 public:
   HttpInitiateConnectionCommand(cuid_t cuid, const std::shared_ptr<Request>& req,
                                 const std::shared_ptr<FileEntry>& fileEntry,
diff --git a/src/HttpListenCommand.h b/src/HttpListenCommand.h
index b2d1ee60..dc7d801a 100644
--- a/src/HttpListenCommand.h
+++ b/src/HttpListenCommand.h
@@ -55,7 +55,7 @@ public:
 
   virtual ~HttpListenCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   bool bindPort(uint16_t port);
 };
diff --git a/src/HttpProxyRequestCommand.h b/src/HttpProxyRequestCommand.h
index 682684f2..5f8b2278 100644
--- a/src/HttpProxyRequestCommand.h
+++ b/src/HttpProxyRequestCommand.h
@@ -52,7 +52,7 @@ public:
                           const std::shared_ptr<SocketCore>& s);
   virtual ~HttpProxyRequestCommand();
 
-  virtual std::unique_ptr<Command> getNextCommand();
+  virtual std::unique_ptr<Command> getNextCommand() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/HttpProxyRequestConnectChain.h b/src/HttpProxyRequestConnectChain.h
index 59cbc4c0..db533374 100644
--- a/src/HttpProxyRequestConnectChain.h
+++ b/src/HttpProxyRequestConnectChain.h
@@ -45,7 +45,7 @@ namespace aria2 {
 struct HttpProxyRequestConnectChain : public ControlChain<ConnectCommand*> {
   HttpProxyRequestConnectChain() {}
   virtual ~HttpProxyRequestConnectChain() {}
-  virtual int run(ConnectCommand* t, DownloadEngine* e)
+  virtual int run(ConnectCommand* t, DownloadEngine* e) CXX11_OVERRIDE
   {
     auto c = make_unique<HttpProxyRequestCommand>
       (t->getCuid(),
diff --git a/src/HttpProxyResponseCommand.h b/src/HttpProxyResponseCommand.h
index 14bd681f..72513655 100644
--- a/src/HttpProxyResponseCommand.h
+++ b/src/HttpProxyResponseCommand.h
@@ -52,7 +52,7 @@ public:
                            const std::shared_ptr<SocketCore>& s);
   virtual ~HttpProxyResponseCommand();
 
-  virtual std::unique_ptr<Command> getNextCommand();
+  virtual std::unique_ptr<Command> getNextCommand() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/HttpRequestCommand.h b/src/HttpRequestCommand.h
index f278a3c3..014ee0e8 100644
--- a/src/HttpRequestCommand.h
+++ b/src/HttpRequestCommand.h
@@ -54,7 +54,7 @@ private:
 
   std::shared_ptr<HttpConnection> httpConnection_;
 protected:
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 public:
   HttpRequestCommand(cuid_t cuid,
                      const std::shared_ptr<Request>& req,
diff --git a/src/HttpRequestConnectChain.h b/src/HttpRequestConnectChain.h
index 4344860e..6f0610f9 100644
--- a/src/HttpRequestConnectChain.h
+++ b/src/HttpRequestConnectChain.h
@@ -47,7 +47,7 @@ namespace aria2 {
 struct HttpRequestConnectChain : public ControlChain<ConnectCommand*> {
   HttpRequestConnectChain() {}
   virtual ~HttpRequestConnectChain() {}
-  virtual int run(ConnectCommand* t, DownloadEngine* e)
+  virtual int run(ConnectCommand* t, DownloadEngine* e) CXX11_OVERRIDE
   {
     std::shared_ptr<SocketRecvBuffer> socketRecvBuffer
       (new SocketRecvBuffer(t->getSocket()));
diff --git a/src/HttpServerBodyCommand.h b/src/HttpServerBodyCommand.h
index 34a1119d..a3086353 100644
--- a/src/HttpServerBodyCommand.h
+++ b/src/HttpServerBodyCommand.h
@@ -79,7 +79,7 @@ public:
 
   virtual ~HttpServerBodyCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/HttpServerCommand.h b/src/HttpServerCommand.h
index aa47f943..c36dc55b 100644
--- a/src/HttpServerCommand.h
+++ b/src/HttpServerCommand.h
@@ -69,7 +69,7 @@ public:
 
   virtual ~HttpServerCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/HttpServerResponseCommand.h b/src/HttpServerResponseCommand.h
index 271c26a5..45d4ea74 100644
--- a/src/HttpServerResponseCommand.h
+++ b/src/HttpServerResponseCommand.h
@@ -42,7 +42,7 @@ namespace aria2 {
 class HttpServerResponseCommand : public AbstractHttpServerResponseCommand {
 protected:
   virtual void afterSend(const std::shared_ptr<HttpServer>& httpServer,
-                         DownloadEngine* e);
+                         DownloadEngine* e) CXX11_OVERRIDE;
 public:
   HttpServerResponseCommand(cuid_t cuid,
                             const std::shared_ptr<HttpServer>& httpServer,
diff --git a/src/HttpSkipResponseCommand.h b/src/HttpSkipResponseCommand.h
index f7c8aef2..6d13ef76 100644
--- a/src/HttpSkipResponseCommand.h
+++ b/src/HttpSkipResponseCommand.h
@@ -61,7 +61,7 @@ private:
 
   void poolConnection() const;
 protected:
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 public:
   HttpSkipResponseCommand
   (cuid_t cuid,
diff --git a/src/IOFile.h b/src/IOFile.h
index 12666c2a..ea98d46f 100644
--- a/src/IOFile.h
+++ b/src/IOFile.h
@@ -58,7 +58,7 @@ public:
   size_t read(void* ptr, size_t count);
   // wrapper for fwrite. Using 1 for 2nd argument of fwrite.
   size_t write(const void* ptr, size_t count);
-  virtual size_t write(const char* str);
+  virtual size_t write(const char* str) CXX11_OVERRIDE;
   // wrapper for fgets
   char* gets(char* s, int size);
   // wrapper for fgets, but trailing '\n' is replaced with '\0'.
diff --git a/src/IndexBtMessage.h b/src/IndexBtMessage.h
index 61bc6da1..209bad81 100644
--- a/src/IndexBtMessage.h
+++ b/src/IndexBtMessage.h
@@ -63,11 +63,11 @@ public:
 
   size_t getIndex() const { return index_; }
 
-  virtual unsigned char* createMessage();
+  virtual unsigned char* createMessage() CXX11_OVERRIDE;
 
-  virtual size_t getMessageLength();
+  virtual size_t getMessageLength() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/IndexBtMessageValidator.h b/src/IndexBtMessageValidator.h
index a8ac2ef4..fad84ad4 100644
--- a/src/IndexBtMessageValidator.h
+++ b/src/IndexBtMessageValidator.h
@@ -50,7 +50,7 @@ public:
 
   ~IndexBtMessageValidator();
 
-  virtual void validate();
+  virtual void validate() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/InitiateConnectionCommand.h b/src/InitiateConnectionCommand.h
index 6c77d5bb..8955fb12 100644
--- a/src/InitiateConnectionCommand.h
+++ b/src/InitiateConnectionCommand.h
@@ -50,7 +50,7 @@ protected:
    * Using nonblocking mode of socket, this funtion returns immediately
    * after send connection packet to the server.
    */
-  virtual bool executeInternal();
+  virtual bool executeInternal() CXX11_OVERRIDE;
 
   // hostname and port are the hostname and port number we are going
   // to connect. If proxy server is used, these values are hostname
diff --git a/src/InitiatorMSEHandshakeCommand.h b/src/InitiatorMSEHandshakeCommand.h
index 5e80ca76..1251d5e0 100644
--- a/src/InitiatorMSEHandshakeCommand.h
+++ b/src/InitiatorMSEHandshakeCommand.h
@@ -73,10 +73,10 @@ private:
 
   void tryNewPeer();
 protected:
-  virtual bool executeInternal();
-  virtual bool prepareForNextPeer(time_t wait);
-  virtual void onAbort();
-  virtual bool exitBeforeExecute();
+  virtual bool executeInternal() CXX11_OVERRIDE;
+  virtual bool prepareForNextPeer(time_t wait) CXX11_OVERRIDE;
+  virtual void onAbort() CXX11_OVERRIDE;
+  virtual bool exitBeforeExecute() CXX11_OVERRIDE;
 public:
   InitiatorMSEHandshakeCommand
   (cuid_t cuid,
diff --git a/src/InorderStreamPieceSelector.h b/src/InorderStreamPieceSelector.h
index 5d5481c8..0e564d21 100644
--- a/src/InorderStreamPieceSelector.h
+++ b/src/InorderStreamPieceSelector.h
@@ -50,9 +50,9 @@ public:
   (size_t& index,
    size_t minSplitSize,
    const unsigned char* ignoreBitfield,
-   size_t length);
+   size_t length) CXX11_OVERRIDE;
 
-  virtual void onBitfieldInit();
+  virtual void onBitfieldInit() CXX11_OVERRIDE;
 private:
   BitfieldMan* bitfieldMan_;
 };
diff --git a/src/InorderURISelector.h b/src/InorderURISelector.h
index 3018be7e..b76e049c 100644
--- a/src/InorderURISelector.h
+++ b/src/InorderURISelector.h
@@ -46,7 +46,8 @@ public:
 
   virtual std::string select
   (FileEntry* fileEntry,
-   const std::vector<std::pair<size_t, std::string> >& usedHosts);
+   const std::vector<std::pair<size_t, std::string> >& usedHosts)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/IteratableChecksumValidator.h b/src/IteratableChecksumValidator.h
index 57d1f78b..2ca15dcb 100644
--- a/src/IteratableChecksumValidator.h
+++ b/src/IteratableChecksumValidator.h
@@ -61,18 +61,18 @@ public:
 
   virtual ~IteratableChecksumValidator();
 
-  virtual void init();
+  virtual void init() CXX11_OVERRIDE;
 
-  virtual void validateChunk();
+  virtual void validateChunk() CXX11_OVERRIDE;
 
-  virtual bool finished() const;
+  virtual bool finished() const CXX11_OVERRIDE;
 
-  virtual int64_t getCurrentOffset() const
+  virtual int64_t getCurrentOffset() const CXX11_OVERRIDE
   {
     return currentOffset_;
   }
 
-  virtual int64_t getTotalLength() const;
+  virtual int64_t getTotalLength() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/IteratableChunkChecksumValidator.h b/src/IteratableChunkChecksumValidator.h
index 3e7375bd..250d153a 100644
--- a/src/IteratableChunkChecksumValidator.h
+++ b/src/IteratableChunkChecksumValidator.h
@@ -66,15 +66,15 @@ public:
 
   virtual ~IteratableChunkChecksumValidator();
 
-  virtual void init();
+  virtual void init() CXX11_OVERRIDE;
 
-  virtual void validateChunk();
+  virtual void validateChunk() CXX11_OVERRIDE;
 
-  virtual bool finished() const;
+  virtual bool finished() const CXX11_OVERRIDE;
 
-  virtual int64_t getCurrentOffset() const;
+  virtual int64_t getCurrentOffset() const CXX11_OVERRIDE;
 
-  virtual int64_t getTotalLength() const;
+  virtual int64_t getTotalLength() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/KeepRunningCommand.h b/src/KeepRunningCommand.h
index 9be030cb..cbd82f59 100644
--- a/src/KeepRunningCommand.h
+++ b/src/KeepRunningCommand.h
@@ -47,7 +47,7 @@ class KeepRunningCommand : public Command {
 public:
   KeepRunningCommand(cuid_t cuid, DownloadEngine* e);
   virtual ~KeepRunningCommand();
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 private:
   DownloadEngine* e_;
 };
diff --git a/src/KqueueEventPoll.h b/src/KqueueEventPoll.h
index c84d2078..9e0ea47e 100644
--- a/src/KqueueEventPoll.h
+++ b/src/KqueueEventPoll.h
@@ -110,19 +110,22 @@ public:
 
   virtual ~KqueueEventPoll();
 
-  virtual void poll(const struct timeval& tv);
+  virtual void poll(const struct timeval& tv) CXX11_OVERRIDE;
 
   virtual bool addEvents(sock_t socket,
-                         Command* command, EventPoll::EventType events);
+                         Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 
   virtual bool deleteEvents(sock_t socket,
-                            Command* command, EventPoll::EventType events);
+                            Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 #ifdef ENABLE_ASYNC_DNS
 
   virtual bool addNameResolver(const std::shared_ptr<AsyncNameResolver>& resolver,
-                               Command* command);
+                               Command* command) CXX11_OVERRIDE;
   virtual bool deleteNameResolver
-  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command);
+  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command)
+    CXX11_OVERRIDE;
 #endif // ENABLE_ASYNC_DNS
 
   static const int IEV_READ = POLLIN;
diff --git a/src/LibgnutlsTLSContext.h b/src/LibgnutlsTLSContext.h
index 8d744bd6..6f238bbe 100644
--- a/src/LibgnutlsTLSContext.h
+++ b/src/LibgnutlsTLSContext.h
@@ -52,23 +52,27 @@ public:
 
   // private key `keyfile' must be decrypted.
   virtual bool addCredentialFile(const std::string& certfile,
-                                 const std::string& keyfile);
+                                 const std::string& keyfile) CXX11_OVERRIDE;
 
-  virtual bool addSystemTrustedCACerts();
+  virtual bool addSystemTrustedCACerts() CXX11_OVERRIDE;
 
   // certfile can contain multiple certificates.
-  virtual bool addTrustedCACertFile(const std::string& certfile);
+  virtual bool addTrustedCACertFile(const std::string& certfile)
+    CXX11_OVERRIDE;
 
-  virtual bool good() const;
+  virtual bool good() const CXX11_OVERRIDE;
 
-  virtual TLSSessionSide getSide() const {
+  virtual TLSSessionSide getSide() const CXX11_OVERRIDE
+  {
     return side_;
   }
 
-  virtual bool getVerifyPeer() const {
+  virtual bool getVerifyPeer() const CXX11_OVERRIDE
+  {
     return verifyPeer_;
   }
-  virtual void setVerifyPeer(bool verify) {
+  virtual void setVerifyPeer(bool verify) CXX11_OVERRIDE
+  {
     verifyPeer_ = verify;
   }
 
diff --git a/src/LibgnutlsTLSSession.h b/src/LibgnutlsTLSSession.h
index 48b7f121..74ddc057 100644
--- a/src/LibgnutlsTLSSession.h
+++ b/src/LibgnutlsTLSSession.h
@@ -49,15 +49,16 @@ class GnuTLSSession : public TLSSession {
 public:
   GnuTLSSession(GnuTLSContext* tlsContext);
   ~GnuTLSSession();
-  virtual int init(sock_t sockfd);
-  virtual int setSNIHostname(const std::string& hostname);
-  virtual int closeConnection();
-  virtual int checkDirection();
-  virtual ssize_t writeData(const void* data, size_t len);
-  virtual ssize_t readData(void* data, size_t len);
-  virtual int tlsConnect(const std::string& hostname, std::string& handshakeErr);
-  virtual int tlsAccept();
-  virtual std::string getLastErrorString();
+  virtual int init(sock_t sockfd) CXX11_OVERRIDE;
+  virtual int setSNIHostname(const std::string& hostname) CXX11_OVERRIDE;
+  virtual int closeConnection() CXX11_OVERRIDE;
+  virtual int checkDirection() CXX11_OVERRIDE;
+  virtual ssize_t writeData(const void* data, size_t len) CXX11_OVERRIDE;
+  virtual ssize_t readData(void* data, size_t len) CXX11_OVERRIDE;
+  virtual int tlsConnect
+  (const std::string& hostname, std::string& handshakeErr) CXX11_OVERRIDE;
+  virtual int tlsAccept() CXX11_OVERRIDE;
+  virtual std::string getLastErrorString() CXX11_OVERRIDE;
 private:
   gnutls_session_t sslSession_;
   GnuTLSContext* tlsContext_;
diff --git a/src/LibsslTLSContext.h b/src/LibsslTLSContext.h
index 00def36a..9462cbb9 100644
--- a/src/LibsslTLSContext.h
+++ b/src/LibsslTLSContext.h
@@ -54,23 +54,27 @@ public:
 
   // private key `keyfile' must be decrypted.
   virtual bool addCredentialFile(const std::string& certfile,
-                                 const std::string& keyfile);
+                                 const std::string& keyfile) CXX11_OVERRIDE;
 
-  virtual bool addSystemTrustedCACerts();
+  virtual bool addSystemTrustedCACerts() CXX11_OVERRIDE;
 
   // certfile can contain multiple certificates.
-  virtual bool addTrustedCACertFile(const std::string& certfile);
+  virtual bool addTrustedCACertFile(const std::string& certfile)
+    CXX11_OVERRIDE;
 
-  virtual bool good() const;
+  virtual bool good() const CXX11_OVERRIDE;
 
-  virtual TLSSessionSide getSide() const {
+  virtual TLSSessionSide getSide() const CXX11_OVERRIDE
+  {
     return side_;
   }
 
-  virtual bool getVerifyPeer() const {
+  virtual bool getVerifyPeer() const CXX11_OVERRIDE
+  {
     return verifyPeer_;
   }
-  virtual void setVerifyPeer(bool verify) {
+  virtual void setVerifyPeer(bool verify) CXX11_OVERRIDE
+  {
     verifyPeer_ = verify;
   }
 
diff --git a/src/LibsslTLSSession.h b/src/LibsslTLSSession.h
index 29412ab8..d43b8e91 100644
--- a/src/LibsslTLSSession.h
+++ b/src/LibsslTLSSession.h
@@ -49,15 +49,16 @@ class OpenSSLTLSSession : public TLSSession {
 public:
   OpenSSLTLSSession(OpenSSLTLSContext* tlsContext);
   virtual ~OpenSSLTLSSession();
-  virtual int init(sock_t sockfd);
-  virtual int setSNIHostname(const std::string& hostname);
-  virtual int closeConnection();
-  virtual int checkDirection();
-  virtual ssize_t writeData(const void* data, size_t len);
-  virtual ssize_t readData(void* data, size_t len);
-  virtual int tlsConnect(const std::string& hostname, std::string& handshakeErr);
-  virtual int tlsAccept();
-  virtual std::string getLastErrorString();
+  virtual int init(sock_t sockfd) CXX11_OVERRIDE;
+  virtual int setSNIHostname(const std::string& hostname) CXX11_OVERRIDE;
+  virtual int closeConnection() CXX11_OVERRIDE;
+  virtual int checkDirection() CXX11_OVERRIDE;
+  virtual ssize_t writeData(const void* data, size_t len) CXX11_OVERRIDE;
+  virtual ssize_t readData(void* data, size_t len) CXX11_OVERRIDE;
+  virtual int tlsConnect
+  (const std::string& hostname, std::string& handshakeErr) CXX11_OVERRIDE;
+  virtual int tlsAccept() CXX11_OVERRIDE;
+  virtual std::string getLastErrorString() CXX11_OVERRIDE;
 private:
   int handshake();
   SSL* ssl_;
diff --git a/src/LibuvEventPoll.h b/src/LibuvEventPoll.h
index b7069176..a6974d1b 100644
--- a/src/LibuvEventPoll.h
+++ b/src/LibuvEventPoll.h
@@ -143,18 +143,21 @@ public:
 
   bool good() const { return loop_; }
 
-  virtual void poll(const struct timeval& tv);
+  virtual void poll(const struct timeval& tv) CXX11_OVERRIDE;
 
   virtual bool addEvents(sock_t socket,
-                         Command* command, EventPoll::EventType events);
+                         Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
   virtual bool deleteEvents(sock_t socket,
-                            Command* command, EventPoll::EventType events);
+                            Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 
 #ifdef ENABLE_ASYNC_DNS
   virtual bool addNameResolver(const std::shared_ptr<AsyncNameResolver>& resolver,
-                               Command* command);
+                               Command* command) CXX11_OVERRIDE;
   virtual bool deleteNameResolver(
-      const std::shared_ptr<AsyncNameResolver>& resolver, Command* command);
+      const std::shared_ptr<AsyncNameResolver>& resolver, Command* command)
+    CXX11_OVERRIDE;
 #endif // ENABLE_ASYNC_DNS
 
   static const int IEV_READ = UV_READABLE;
diff --git a/src/LongestSequencePieceSelector.h b/src/LongestSequencePieceSelector.h
index d35f38a5..6d1d908f 100644
--- a/src/LongestSequencePieceSelector.h
+++ b/src/LongestSequencePieceSelector.h
@@ -46,7 +46,8 @@ public:
   // { 1,2,3,4,7,10,11,12,13,14,15,100,112,113,114 }, then
   // returns 15 because { 10, 11, 12, 13, 14, 15 } is the longest sequence.
   virtual bool select
-  (size_t& index, const unsigned char* bitfield, size_t nbits) const;
+  (size_t& index, const unsigned char* bitfield, size_t nbits) const
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/LpdDispatchMessageCommand.h b/src/LpdDispatchMessageCommand.h
index 1fa8b018..a1dd2007 100644
--- a/src/LpdDispatchMessageCommand.h
+++ b/src/LpdDispatchMessageCommand.h
@@ -59,7 +59,7 @@ public:
 
   ~LpdDispatchMessageCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void setBtRuntime(const std::shared_ptr<BtRuntime>& btRuntime)
   {
diff --git a/src/LpdReceiveMessageCommand.h b/src/LpdReceiveMessageCommand.h
index 09f3fe60..d5a487dd 100644
--- a/src/LpdReceiveMessageCommand.h
+++ b/src/LpdReceiveMessageCommand.h
@@ -55,7 +55,7 @@ public:
    DownloadEngine* e);
   virtual ~LpdReceiveMessageCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   const std::shared_ptr<LpdMessageReceiver>& getLpdMessageReceiver() const
   {
diff --git a/src/MemoryPreDownloadHandler.h b/src/MemoryPreDownloadHandler.h
index 3c348982..d8598d42 100644
--- a/src/MemoryPreDownloadHandler.h
+++ b/src/MemoryPreDownloadHandler.h
@@ -48,7 +48,7 @@ public:
 
   virtual ~MemoryPreDownloadHandler() {}
 
-  virtual void execute(RequestGroup* requestGroup)
+  virtual void execute(RequestGroup* requestGroup) CXX11_OVERRIDE
   {
     std::shared_ptr<DiskWriterFactory> dwf(new DiskWriterFactoryType());
     requestGroup->setDiskWriterFactory(dwf);
diff --git a/src/MetalinkParserStateImpl.h b/src/MetalinkParserStateImpl.h
index 94c823d6..8b64fa52 100644
--- a/src/MetalinkParserStateImpl.h
+++ b/src/MetalinkParserStateImpl.h
@@ -51,7 +51,7 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 };
 
 class InitialMetalinkParserState:public MetalinkParserState
@@ -61,7 +61,7 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/MetalinkParserStateMachine.h b/src/MetalinkParserStateMachine.h
index 0414a4ac..13b6581c 100644
--- a/src/MetalinkParserStateMachine.h
+++ b/src/MetalinkParserStateMachine.h
@@ -95,23 +95,23 @@ public:
 
   virtual ~MetalinkParserStateMachine();
 
-  virtual bool needsCharactersBuffering() const;
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE;
 
-  virtual bool finished() const;
+  virtual bool finished() const CXX11_OVERRIDE;
 
   virtual void beginElement
   (const char* localname,
    const char* prefix,
    const char* nsUri,
-   const std::vector<XmlAttr>& attrs);
+   const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement
   (const char* localname,
    const char* prefix,
    const char* nsUri,
-   const std::string& characters);
+   const std::string& characters) CXX11_OVERRIDE;
 
-  virtual void reset();
+  virtual void reset() CXX11_OVERRIDE;
 
   void setSkipTagState();
 
diff --git a/src/MetalinkParserStateV3Impl.h b/src/MetalinkParserStateV3Impl.h
index dccc2298..dcac3d70 100644
--- a/src/MetalinkParserStateV3Impl.h
+++ b/src/MetalinkParserStateV3Impl.h
@@ -49,7 +49,7 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 };
 
 class FilesMetalinkParserState:public MetalinkParserState
@@ -59,9 +59,9 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -74,15 +74,15 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(MetalinkParserStateMachine* psm,
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -95,9 +95,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -110,9 +110,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -125,9 +125,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -140,9 +140,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -155,9 +155,9 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -170,9 +170,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -185,15 +185,15 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(MetalinkParserStateMachine* psm,
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -206,9 +206,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-			  const std::string& characters);
+			  const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -221,9 +221,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -236,9 +236,9 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -251,9 +251,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
diff --git a/src/MetalinkParserStateV4Impl.h b/src/MetalinkParserStateV4Impl.h
index 81628f32..123d2f8f 100644
--- a/src/MetalinkParserStateV4Impl.h
+++ b/src/MetalinkParserStateV4Impl.h
@@ -49,7 +49,7 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 };
 
 class FileMetalinkParserStateV4:public MetalinkParserState
@@ -59,15 +59,15 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(MetalinkParserStateMachine* psm,
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -80,9 +80,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -95,9 +95,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -110,9 +110,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -125,9 +125,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -140,9 +140,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -155,15 +155,15 @@ public:
                             const char* localname,
                             const char* prefix,
                             const char* nsUri,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(MetalinkParserStateMachine* psm,
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -176,9 +176,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-			  const std::string& characters);
+			  const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -191,9 +191,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -206,9 +206,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
@@ -221,9 +221,9 @@ public:
                           const char* localname,
                           const char* prefix,
                           const char* nsUri,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
   {
     return true;
   }
diff --git a/src/MetalinkPostDownloadHandler.h b/src/MetalinkPostDownloadHandler.h
index 1f975ea7..8b3fe195 100644
--- a/src/MetalinkPostDownloadHandler.h
+++ b/src/MetalinkPostDownloadHandler.h
@@ -48,7 +48,7 @@ public:
 
   virtual void
   getNextRequestGroups(std::vector<std::shared_ptr<RequestGroup> >& groups,
-                       RequestGroup* requestGroup);
+                       RequestGroup* requestGroup) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/MultiDiskAdaptor.h b/src/MultiDiskAdaptor.h
index bf85da90..800fe788 100644
--- a/src/MultiDiskAdaptor.h
+++ b/src/MultiDiskAdaptor.h
@@ -131,36 +131,38 @@ public:
   MultiDiskAdaptor();
   ~MultiDiskAdaptor();
 
-  virtual void initAndOpenFile();
+  virtual void initAndOpenFile() CXX11_OVERRIDE;
 
-  virtual void openFile();
+  virtual void openFile() CXX11_OVERRIDE;
 
-  virtual void openExistingFile();
+  virtual void openExistingFile() CXX11_OVERRIDE;
 
-  virtual void closeFile();
+  virtual void closeFile() CXX11_OVERRIDE;
 
   virtual void writeData(const unsigned char* data, size_t len,
-                         int64_t offset);
+                         int64_t offset) CXX11_OVERRIDE;
 
-  virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset);
+  virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE;
 
-  virtual void writeCache(const WrDiskCacheEntry* entry);
+  virtual void writeCache(const WrDiskCacheEntry* entry) CXX11_OVERRIDE;
 
-  virtual bool fileExists();
+  virtual bool fileExists() CXX11_OVERRIDE;
 
-  virtual int64_t size();
+  virtual int64_t size() CXX11_OVERRIDE;
 
-  virtual std::unique_ptr<FileAllocationIterator> fileAllocationIterator();
+  virtual std::unique_ptr<FileAllocationIterator> fileAllocationIterator()
+    CXX11_OVERRIDE;
 
-  virtual void enableReadOnly();
+  virtual void enableReadOnly() CXX11_OVERRIDE;
 
-  virtual void disableReadOnly();
+  virtual void disableReadOnly() CXX11_OVERRIDE;
 
-  virtual bool isReadOnlyEnabled() const { return readOnly_; }
+  virtual bool isReadOnlyEnabled() const CXX11_OVERRIDE { return readOnly_; }
 
   // Enables mmap feature. This method must be called after files are
   // opened.
-  virtual void enableMmap();
+  virtual void enableMmap() CXX11_OVERRIDE;
 
   void setPieceLength(int32_t pieceLength)
   {
@@ -171,11 +173,11 @@ public:
     return pieceLength_;
   }
 
-  virtual void cutTrailingGarbage();
+  virtual void cutTrailingGarbage() CXX11_OVERRIDE;
 
   void setMaxOpenFiles(int maxOpenFiles);
 
-  virtual size_t utime(const Time& actime, const Time& modtime);
+  virtual size_t utime(const Time& actime, const Time& modtime) CXX11_OVERRIDE;
 
   const DiskWriterEntries& getDiskWriterEntries() const
   {
diff --git a/src/MultiFileAllocationIterator.h b/src/MultiFileAllocationIterator.h
index 2f55d234..ea3181a8 100644
--- a/src/MultiFileAllocationIterator.h
+++ b/src/MultiFileAllocationIterator.h
@@ -57,13 +57,13 @@ public:
 
   virtual ~MultiFileAllocationIterator();
 
-  virtual void allocateChunk();
+  virtual void allocateChunk() CXX11_OVERRIDE;
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
-  virtual int64_t getCurrentLength();
+  virtual int64_t getCurrentLength() CXX11_OVERRIDE;
 
-  virtual int64_t getTotalLength();
+  virtual int64_t getTotalLength() CXX11_OVERRIDE;
 
   const DiskWriterEntries& getDiskWriterEntries() const;
 };
diff --git a/src/NameResolveCommand.h b/src/NameResolveCommand.h
index 66e1ae82..a8433541 100644
--- a/src/NameResolveCommand.h
+++ b/src/NameResolveCommand.h
@@ -74,7 +74,7 @@ public:
 
   virtual ~NameResolveCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/Netrc.h b/src/Netrc.h
index a2845f78..3b44b173 100644
--- a/src/Netrc.h
+++ b/src/Netrc.h
@@ -66,7 +66,7 @@ public:
 
   virtual ~Authenticator();
 
-  virtual bool match(const std::string& hostname) const;
+  virtual bool match(const std::string& hostname) const CXX11_OVERRIDE;
 
   const std::string& getMachine() const
   {
@@ -107,7 +107,7 @@ public:
 
   virtual ~DefaultAuthenticator();
 
-  virtual bool match(const std::string& hostname) const;
+  virtual bool match(const std::string& hostname) const CXX11_OVERRIDE;
 };
 
 class Netrc {
diff --git a/src/NetrcAuthResolver.h b/src/NetrcAuthResolver.h
index d9b74acd..4e3c6d4e 100644
--- a/src/NetrcAuthResolver.h
+++ b/src/NetrcAuthResolver.h
@@ -53,7 +53,7 @@ public:
   NetrcAuthResolver();
 
   virtual std::unique_ptr<AuthConfig> resolveAuthConfig
-  (const std::string& hostname);
+  (const std::string& hostname) CXX11_OVERRIDE;
 
   void setNetrc(Netrc* netrc);
 
diff --git a/src/NullOutputFile.h b/src/NullOutputFile.h
index 97c05562..a1a71c0e 100644
--- a/src/NullOutputFile.h
+++ b/src/NullOutputFile.h
@@ -42,10 +42,11 @@ namespace aria2 {
 class NullOutputFile:public OutputFile {
 public:
   virtual ~NullOutputFile() {}
-  virtual size_t write(const char* str) { return 0; }
-  virtual int flush() { return 0; }
-  virtual int vprintf(const char* format, va_list va) { return 0; }
-  virtual bool supportsColor() { return false; }
+  virtual size_t write(const char* str) CXX11_OVERRIDE { return 0; }
+  virtual int flush() CXX11_OVERRIDE { return 0; }
+  virtual int vprintf(const char* format, va_list va) CXX11_OVERRIDE
+  { return 0; }
+  virtual bool supportsColor() CXX11_OVERRIDE { return false; }
 };
 
 } // namespace aria2
diff --git a/src/NullProgressInfoFile.h b/src/NullProgressInfoFile.h
index 7ae2e44f..baea4679 100644
--- a/src/NullProgressInfoFile.h
+++ b/src/NullProgressInfoFile.h
@@ -44,20 +44,20 @@ class NullProgressInfoFile:public BtProgressInfoFile {
 public:
   virtual ~NullProgressInfoFile() {}
 
-  virtual std::string getFilename()
+  virtual std::string getFilename() CXX11_OVERRIDE
   {
     return A2STR::NIL;
   }
 
-  virtual bool exists() { return false; }
+  virtual bool exists() CXX11_OVERRIDE { return false; }
 
-  virtual void save() {}
+  virtual void save() CXX11_OVERRIDE {}
 
-  virtual void load() {}
+  virtual void load() CXX11_OVERRIDE {}
 
-  virtual void removeFile() {}
+  virtual void removeFile() CXX11_OVERRIDE {}
 
-  virtual void updateFilename() {}
+  virtual void updateFilename() CXX11_OVERRIDE {}
 };
 
 } // namespace aria2
diff --git a/src/NullSinkStreamFilter.h b/src/NullSinkStreamFilter.h
index e3dc8f43..ead7bd91 100644
--- a/src/NullSinkStreamFilter.h
+++ b/src/NullSinkStreamFilter.h
@@ -45,32 +45,32 @@ private:
 public:
   NullSinkStreamFilter():bytesProcessed_(0) {}
 
-  virtual void init() {}
+  virtual void init() CXX11_OVERRIDE {}
 
   virtual ssize_t transform
   (const std::shared_ptr<BinaryStream>& out,
    const std::shared_ptr<Segment>& segment,
-   const unsigned char* inbuf, size_t inlen)
+   const unsigned char* inbuf, size_t inlen) CXX11_OVERRIDE
   {
     bytesProcessed_ = inlen;
     return bytesProcessed_;
   }
 
-  virtual bool finished()
+  virtual bool finished() CXX11_OVERRIDE
   {
     return true;
   }
 
-  virtual void release() {}
+  virtual void release() CXX11_OVERRIDE {}
 
-  virtual const std::string& getName() const
+  virtual const std::string& getName() const CXX11_OVERRIDE
   {
     return NAME;
   }
 
   static const std::string NAME;
 
-  virtual size_t getBytesProcessed() const
+  virtual size_t getBytesProcessed() const CXX11_OVERRIDE
   {
     return bytesProcessed_;
   }
diff --git a/src/NullStatCalc.h b/src/NullStatCalc.h
index e9de0972..21788aaf 100644
--- a/src/NullStatCalc.h
+++ b/src/NullStatCalc.h
@@ -43,7 +43,7 @@ class NullStatCalc:public StatCalc {
 public:
   virtual ~NullStatCalc() {}
 
-  virtual void calculateStat(const DownloadEngine* e) {}
+  virtual void calculateStat(const DownloadEngine* e) CXX11_OVERRIDE {}
 };
 
 } // namespace aria2
diff --git a/src/OptionHandlerException.h b/src/OptionHandlerException.h
index 5426ee9d..77bc4ca7 100644
--- a/src/OptionHandlerException.h
+++ b/src/OptionHandlerException.h
@@ -44,7 +44,7 @@ class OptionHandlerException:public RecoverableException {
 private:
   const Pref* pref_;
 protected:
-  virtual std::shared_ptr<Exception> copy() const;
+  virtual std::shared_ptr<Exception> copy() const CXX11_OVERRIDE;
 public:
   OptionHandlerException(const char* file, int line,
                          const Pref* pref);
diff --git a/src/OptionHandlerImpl.h b/src/OptionHandlerImpl.h
index eb699f85..05d66fd2 100644
--- a/src/OptionHandlerImpl.h
+++ b/src/OptionHandlerImpl.h
@@ -55,8 +55,9 @@ public:
                        OptionHandler::ARG_TYPE argType = OptionHandler::REQ_ARG,
                        char shortName = 0);
   virtual ~BooleanOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class IntegerRangeOptionHandler : public AbstractOptionHandler {
@@ -70,8 +71,9 @@ public:
                             int32_t min, int32_t max,
                             char shortName = 0);
   virtual ~IntegerRangeOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class NumberOptionHandler : public AbstractOptionHandler {
@@ -87,9 +89,10 @@ public:
                       char shortName = 0);
   virtual ~NumberOptionHandler();
 
-  virtual void parseArg(Option& option, const std::string& optarg) const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
   void parseArg(Option& option, int64_t number) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class UnitNumberOptionHandler : public NumberOptionHandler {
@@ -101,7 +104,8 @@ public:
                           int64_t max = -1,
                           char shortName = 0);
   virtual ~UnitNumberOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
 };
 
 class FloatNumberOptionHandler : public AbstractOptionHandler {
@@ -115,8 +119,9 @@ public:
                            double min = -1, double max = -1,
                            char shortName = 0);
   virtual ~FloatNumberOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class DefaultOptionHandler : public AbstractOptionHandler {
@@ -130,8 +135,9 @@ public:
                        OptionHandler::ARG_TYPE argType = OptionHandler::REQ_ARG,
                        char shortName = 0);
   virtual ~DefaultOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class CumulativeOptionHandler : public AbstractOptionHandler {
@@ -148,8 +154,9 @@ public:
                           OptionHandler::REQ_ARG,
                           char shortName = 0);
   virtual ~CumulativeOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class IndexOutOptionHandler : public AbstractOptionHandler {
@@ -158,8 +165,9 @@ public:
                         const char* description,
                         char shortName = 0);
   virtual ~IndexOutOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 #ifdef ENABLE_MESSAGE_DIGEST
@@ -169,8 +177,9 @@ public:
                         const char* description,
                         char shortName = 0);
   virtual ~ChecksumOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 #endif // ENABLE_MESSAGE_DIGEST
 
@@ -184,8 +193,9 @@ public:
                          std::vector<std::string> validParamValues,
                          char shortName = 0);
   virtual ~ParameterOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class HostPortOptionHandler : public AbstractOptionHandler {
@@ -200,10 +210,11 @@ public:
                         const Pref* portOptionName,
                         char shortName = 0);
   virtual ~HostPortOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
   void setHostAndPort
   (Option& option, const std::string& hostname, uint16_t port) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class HttpProxyOptionHandler : public AbstractOptionHandler {
@@ -216,8 +227,9 @@ public:
                          const std::string& defaultValue,
                          char shortName = 0);
   virtual ~HttpProxyOptionHandler();
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class LocalFilePathOptionHandler : public AbstractOptionHandler {
@@ -230,8 +242,9 @@ public:
    const std::string& defaultValue = NO_DEFAULT_VALUE,
    bool acceptStdin = false,
    char shortName = 0);
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 class PrioritizePieceOptionHandler:public AbstractOptionHandler {
@@ -241,8 +254,9 @@ public:
    const char* description = NO_DESCRIPTION,
    const std::string& defaultValue = NO_DEFAULT_VALUE,
    char shortName = 0);
-  virtual void parseArg(Option& option, const std::string& optarg) const;
-  virtual std::string createPossibleValuesString() const;
+  virtual void parseArg(Option& option, const std::string& optarg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
 };
 
 // This class is used to deprecate option and optionally handle its
@@ -259,31 +273,32 @@ public:
   (OptionHandler* depOptHandler,
    const OptionHandler* repOptHandler = 0);
   virtual ~DeprecatedOptionHandler();
-  virtual void parse(Option& option, const std::string& arg) const;
-  virtual std::string createPossibleValuesString() const;
-  virtual bool hasTag(uint32_t tag) const;
-  virtual void addTag(uint32_t tag);
-  virtual std::string toTagString() const;
-  virtual const char* getName() const;
-  virtual const char* getDescription() const;
-  virtual const std::string& getDefaultValue() const;
-  virtual bool isHidden() const;
-  virtual void hide();
-  virtual const Pref* getPref() const;
-  virtual ARG_TYPE getArgType() const;
-  virtual char getShortName() const;
-  virtual bool getEraseAfterParse() const;
-  virtual void setEraseAfterParse(bool eraseAfterParse);
-  virtual bool getInitialOption() const;
-  virtual void setInitialOption(bool f);
-  virtual bool getChangeOption() const;
-  virtual void setChangeOption(bool f);
-  virtual bool getChangeOptionForReserved() const;
-  virtual void setChangeOptionForReserved(bool f);
-  virtual bool getChangeGlobalOption() const;
-  virtual void setChangeGlobalOption(bool f);
-  virtual bool getCumulative() const;
-  virtual void setCumulative(bool f);
+  virtual void parse(Option& option, const std::string& arg) const
+    CXX11_OVERRIDE;
+  virtual std::string createPossibleValuesString() const CXX11_OVERRIDE;
+  virtual bool hasTag(uint32_t tag) const CXX11_OVERRIDE;
+  virtual void addTag(uint32_t tag) CXX11_OVERRIDE;
+  virtual std::string toTagString() const CXX11_OVERRIDE;
+  virtual const char* getName() const CXX11_OVERRIDE;
+  virtual const char* getDescription() const CXX11_OVERRIDE;
+  virtual const std::string& getDefaultValue() const CXX11_OVERRIDE;
+  virtual bool isHidden() const CXX11_OVERRIDE;
+  virtual void hide() CXX11_OVERRIDE;
+  virtual const Pref* getPref() const CXX11_OVERRIDE;
+  virtual ARG_TYPE getArgType() const CXX11_OVERRIDE;
+  virtual char getShortName() const CXX11_OVERRIDE;
+  virtual bool getEraseAfterParse() const CXX11_OVERRIDE;
+  virtual void setEraseAfterParse(bool eraseAfterParse) CXX11_OVERRIDE;
+  virtual bool getInitialOption() const CXX11_OVERRIDE;
+  virtual void setInitialOption(bool f) CXX11_OVERRIDE;
+  virtual bool getChangeOption() const CXX11_OVERRIDE;
+  virtual void setChangeOption(bool f) CXX11_OVERRIDE;
+  virtual bool getChangeOptionForReserved() const CXX11_OVERRIDE;
+  virtual void setChangeOptionForReserved(bool f) CXX11_OVERRIDE;
+  virtual bool getChangeGlobalOption() const CXX11_OVERRIDE;
+  virtual void setChangeGlobalOption(bool f) CXX11_OVERRIDE;
+  virtual bool getCumulative() const CXX11_OVERRIDE;
+  virtual void setCumulative(bool f) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/PeerAbstractCommand.h b/src/PeerAbstractCommand.h
index af006751..0e9e3b7c 100644
--- a/src/PeerAbstractCommand.h
+++ b/src/PeerAbstractCommand.h
@@ -103,7 +103,7 @@ public:
 
   virtual ~PeerAbstractCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/PeerChokeCommand.h b/src/PeerChokeCommand.h
index 8cf5e7a5..51ec751b 100644
--- a/src/PeerChokeCommand.h
+++ b/src/PeerChokeCommand.h
@@ -58,7 +58,7 @@ public:
 
   virtual ~PeerChokeCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void setPeerStorage(const std::shared_ptr<PeerStorage>& peerStorage);
 
diff --git a/src/PeerInitiateConnectionCommand.h b/src/PeerInitiateConnectionCommand.h
index 50a4f514..7183ef0e 100644
--- a/src/PeerInitiateConnectionCommand.h
+++ b/src/PeerInitiateConnectionCommand.h
@@ -56,10 +56,10 @@ private:
 
   bool mseHandshakeEnabled_;
 protected:
-  virtual bool executeInternal();
-  virtual bool prepareForNextPeer(time_t wait);
-  virtual void onAbort();
-  virtual bool exitBeforeExecute();
+  virtual bool executeInternal() CXX11_OVERRIDE;
+  virtual bool prepareForNextPeer(time_t wait) CXX11_OVERRIDE;
+  virtual void onAbort() CXX11_OVERRIDE;
+  virtual bool exitBeforeExecute() CXX11_OVERRIDE;
 
 public:
   PeerInitiateConnectionCommand(cuid_t cuid,
diff --git a/src/PeerInteractionCommand.h b/src/PeerInteractionCommand.h
index dae71ddc..f31326b8 100644
--- a/src/PeerInteractionCommand.h
+++ b/src/PeerInteractionCommand.h
@@ -68,11 +68,11 @@ private:
 
   const std::shared_ptr<Option>& getOption() const;
 protected:
-  virtual bool executeInternal();
-  virtual bool prepareForNextPeer(time_t wait);
-  virtual void onAbort();
-  virtual void onFailure(const Exception& err);
-  virtual bool exitBeforeExecute();
+  virtual bool executeInternal() CXX11_OVERRIDE;
+  virtual bool prepareForNextPeer(time_t wait) CXX11_OVERRIDE;
+  virtual void onAbort() CXX11_OVERRIDE;
+  virtual void onFailure(const Exception& err) CXX11_OVERRIDE;
+  virtual bool exitBeforeExecute() CXX11_OVERRIDE;
 public:
   PeerInteractionCommand(cuid_t cuid,
                          RequestGroup* requestGroup,
diff --git a/src/PeerListenCommand.h b/src/PeerListenCommand.h
index fa59cfdd..544378f5 100644
--- a/src/PeerListenCommand.h
+++ b/src/PeerListenCommand.h
@@ -56,7 +56,7 @@ public:
 
   virtual ~PeerListenCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   /**
    * Binds port. If successful, the binded port number is assinged to port and
diff --git a/src/PeerReceiveHandshakeCommand.h b/src/PeerReceiveHandshakeCommand.h
index 8c0adfff..c7b76029 100644
--- a/src/PeerReceiveHandshakeCommand.h
+++ b/src/PeerReceiveHandshakeCommand.h
@@ -48,8 +48,8 @@ class PeerReceiveHandshakeCommand:public PeerAbstractCommand
 private:
   std::shared_ptr<PeerConnection> peerConnection_;
 protected:
-  virtual bool executeInternal();
-  virtual bool exitBeforeExecute();
+  virtual bool executeInternal() CXX11_OVERRIDE;
+  virtual bool exitBeforeExecute() CXX11_OVERRIDE;
 public:
   PeerReceiveHandshakeCommand
   (cuid_t cuid,
diff --git a/src/PieceHashCheckIntegrityEntry.h b/src/PieceHashCheckIntegrityEntry.h
index e380e79c..fda4b02e 100644
--- a/src/PieceHashCheckIntegrityEntry.h
+++ b/src/PieceHashCheckIntegrityEntry.h
@@ -48,9 +48,9 @@ public:
 
   virtual ~PieceHashCheckIntegrityEntry();
 
-  virtual bool isValidationReady();
+  virtual bool isValidationReady() CXX11_OVERRIDE;
 
-  virtual void initValidator();
+  virtual void initValidator() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/PiecedSegment.h b/src/PiecedSegment.h
index 4e7fda31..375ef3a0 100644
--- a/src/PiecedSegment.h
+++ b/src/PiecedSegment.h
@@ -54,27 +54,27 @@ public:
 
   virtual ~PiecedSegment();
 
-  virtual bool complete() const;
+  virtual bool complete() const CXX11_OVERRIDE;
 
-  virtual size_t getIndex() const;
+  virtual size_t getIndex() const CXX11_OVERRIDE;
 
-  virtual int64_t getPosition() const;
+  virtual int64_t getPosition() const CXX11_OVERRIDE;
 
-  virtual int64_t getPositionToWrite() const;
+  virtual int64_t getPositionToWrite() const CXX11_OVERRIDE;
 
-  virtual int32_t getLength() const;
+  virtual int32_t getLength() const CXX11_OVERRIDE;
 
-  virtual int32_t getSegmentLength() const
+  virtual int32_t getSegmentLength() const CXX11_OVERRIDE
   {
     return pieceLength_;
   }
 
-  virtual int32_t getWrittenLength() const
+  virtual int32_t getWrittenLength() const CXX11_OVERRIDE
   {
     return writtenLength_;
   }
 
-  virtual void updateWrittenLength(int32_t bytes);
+  virtual void updateWrittenLength(int32_t bytes) CXX11_OVERRIDE;
 
 #ifdef ENABLE_MESSAGE_DIGEST
 
@@ -82,17 +82,17 @@ public:
   virtual bool updateHash
   (int32_t begin,
    const unsigned char* data,
-   size_t dataLength);
+   size_t dataLength) CXX11_OVERRIDE;
 
-  virtual bool isHashCalculated() const;
+  virtual bool isHashCalculated() const CXX11_OVERRIDE;
 
-  virtual std::string getDigest();
+  virtual std::string getDigest() CXX11_OVERRIDE;
 
 #endif // ENABLE_MESSAGE_DIGEST
 
-  virtual void clear(WrDiskCache* diskCache);
+  virtual void clear(WrDiskCache* diskCache) CXX11_OVERRIDE;
 
-  virtual std::shared_ptr<Piece> getPiece() const;
+  virtual std::shared_ptr<Piece> getPiece() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/PollEventPoll.h b/src/PollEventPoll.h
index 730a7da6..0b88baef 100644
--- a/src/PollEventPoll.h
+++ b/src/PollEventPoll.h
@@ -104,19 +104,22 @@ public:
 
   virtual ~PollEventPoll();
 
-  virtual void poll(const struct timeval& tv);
+  virtual void poll(const struct timeval& tv) CXX11_OVERRIDE;
 
   virtual bool addEvents(sock_t socket,
-                         Command* command, EventPoll::EventType events);
+                         Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 
   virtual bool deleteEvents(sock_t socket,
-                            Command* command, EventPoll::EventType events);
+                            Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 #ifdef ENABLE_ASYNC_DNS
 
   virtual bool addNameResolver(const std::shared_ptr<AsyncNameResolver>& resolver,
-                               Command* command);
+                               Command* command) CXX11_OVERRIDE;
   virtual bool deleteNameResolver
-  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command);
+  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command)
+    CXX11_OVERRIDE;
 #endif // ENABLE_ASYNC_DNS
 
   static const int IEV_READ = POLLIN;
diff --git a/src/PortEventPoll.h b/src/PortEventPoll.h
index 3f25e3dd..4071c17b 100644
--- a/src/PortEventPoll.h
+++ b/src/PortEventPoll.h
@@ -112,19 +112,22 @@ public:
 
   virtual ~PortEventPoll();
 
-  virtual void poll(const struct timeval& tv);
+  virtual void poll(const struct timeval& tv) CXX11_OVERRIDE;
 
   virtual bool addEvents(sock_t socket,
-                         Command* command, EventPoll::EventType events);
+                         Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 
   virtual bool deleteEvents(sock_t socket,
-                            Command* command, EventPoll::EventType events);
+                            Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 #ifdef ENABLE_ASYNC_DNS
 
   virtual bool addNameResolver(const std::shared_ptr<AsyncNameResolver>& resolver,
-                               Command* command);
+                               Command* command) CXX11_OVERRIDE;
   virtual bool deleteNameResolver
-  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command);
+  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command)
+    CXX11_OVERRIDE;
 #endif // ENABLE_ASYNC_DNS
 
   static const int IEV_READ = POLLIN;
diff --git a/src/PriorityPieceSelector.h b/src/PriorityPieceSelector.h
index 8360af56..024ecdb2 100644
--- a/src/PriorityPieceSelector.h
+++ b/src/PriorityPieceSelector.h
@@ -51,7 +51,8 @@ public:
   PriorityPieceSelector(const std::shared_ptr<PieceSelector>& selector);
 
   virtual bool select
-  (size_t& index, const unsigned char* bitfield, size_t nbits) const;
+  (size_t& index, const unsigned char* bitfield, size_t nbits) const
+    CXX11_OVERRIDE;
 
   template<typename InputIterator>
   void setPriorityPiece(InputIterator first, InputIterator last)
diff --git a/src/RangeBtMessage.h b/src/RangeBtMessage.h
index a9c590e3..0da6c557 100644
--- a/src/RangeBtMessage.h
+++ b/src/RangeBtMessage.h
@@ -74,11 +74,11 @@ public:
 
   void setLength(int32_t length) { length_ = length; }
 
-  virtual unsigned char* createMessage();
+  virtual unsigned char* createMessage() CXX11_OVERRIDE;
 
-  virtual size_t getMessageLength();
+  virtual size_t getMessageLength() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/RangeBtMessageValidator.h b/src/RangeBtMessageValidator.h
index 759a4aa8..e6747a3a 100644
--- a/src/RangeBtMessageValidator.h
+++ b/src/RangeBtMessageValidator.h
@@ -53,7 +53,7 @@ public:
 
   ~RangeBtMessageValidator();
 
-  virtual void validate();
+  virtual void validate() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/RarestPieceSelector.h b/src/RarestPieceSelector.h
index 91abe956..6d1ea86c 100644
--- a/src/RarestPieceSelector.h
+++ b/src/RarestPieceSelector.h
@@ -50,7 +50,8 @@ public:
   RarestPieceSelector(const std::shared_ptr<PieceStatMan>& pieceStatMan);
 
   virtual bool select
-  (size_t& index, const unsigned char* bitfield, size_t nbits) const;
+  (size_t& index, const unsigned char* bitfield, size_t nbits) const
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/RealtimeCommand.h b/src/RealtimeCommand.h
index 6373a126..f06fbf81 100644
--- a/src/RealtimeCommand.h
+++ b/src/RealtimeCommand.h
@@ -62,7 +62,7 @@ public:
 
   virtual ~RealtimeCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   virtual bool executeInternal() = 0;
 
diff --git a/src/ReceiverMSEHandshakeCommand.h b/src/ReceiverMSEHandshakeCommand.h
index a5feea30..ee82e536 100644
--- a/src/ReceiverMSEHandshakeCommand.h
+++ b/src/ReceiverMSEHandshakeCommand.h
@@ -64,8 +64,8 @@ private:
 
   void createCommand();
 protected:
-  virtual bool executeInternal();
-  virtual bool exitBeforeExecute();
+  virtual bool executeInternal() CXX11_OVERRIDE;
+  virtual bool exitBeforeExecute() CXX11_OVERRIDE;
 public:
   ReceiverMSEHandshakeCommand(cuid_t cuid,
                               const std::shared_ptr<Peer>& peer,
diff --git a/src/RecoverableException.h b/src/RecoverableException.h
index e5a98d81..4a880d22 100644
--- a/src/RecoverableException.h
+++ b/src/RecoverableException.h
@@ -40,7 +40,7 @@ namespace aria2 {
 
 class RecoverableException:public Exception {
 protected:
-  virtual std::shared_ptr<Exception> copy() const;
+  virtual std::shared_ptr<Exception> copy() const CXX11_OVERRIDE;
 public:
   RecoverableException(const char* file, int line, const std::string& msg);
 
diff --git a/src/RpcMethodImpl.h b/src/RpcMethodImpl.h
index 0a5a9b4a..fa39e6fd 100644
--- a/src/RpcMethodImpl.h
+++ b/src/RpcMethodImpl.h
@@ -128,7 +128,7 @@ void toStringList(OutputIterator out, const List* src)
 class AddUriRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -139,7 +139,7 @@ public:
 class RemoveRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -150,7 +150,7 @@ public:
 class ForceRemoveRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -161,7 +161,7 @@ public:
 class PauseRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -172,7 +172,7 @@ public:
 class ForcePauseRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -183,7 +183,7 @@ public:
 class PauseAllRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -194,7 +194,7 @@ public:
 class ForcePauseAllRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -205,7 +205,7 @@ public:
 class UnpauseRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -216,7 +216,7 @@ public:
 class UnpauseAllRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -228,7 +228,7 @@ public:
 class AddTorrentRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -241,7 +241,7 @@ public:
 class AddMetalinkRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -253,7 +253,7 @@ public:
 class PurgeDownloadResultRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -264,7 +264,7 @@ public:
 class RemoveDownloadResultRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -275,7 +275,7 @@ public:
 class GetUrisRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -286,7 +286,7 @@ public:
 class GetFilesRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -298,7 +298,7 @@ public:
 class GetPeersRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -310,7 +310,7 @@ public:
 class GetServersRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -321,7 +321,7 @@ public:
 class TellStatusRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -332,7 +332,7 @@ public:
 class TellActiveRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -377,7 +377,7 @@ protected:
   typedef IndexedList<a2_gid_t, std::shared_ptr<T> > ItemListType;
 
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e)
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE
   {
     const Integer* offsetParam = checkRequiredParam<Integer>(req, 0);
     const Integer* numParam = checkRequiredInteger(req, 1, IntegerGE(0));
@@ -415,13 +415,14 @@ protected:
 class TellWaitingRpcMethod:
     public AbstractPaginationRpcMethod<RequestGroup> {
 protected:
-  virtual const RequestGroupList& getItems(DownloadEngine* e) const;
+  virtual const RequestGroupList& getItems(DownloadEngine* e) const
+    CXX11_OVERRIDE;
 
   virtual void createEntry
   (const std::shared_ptr<Dict>& entryDict,
    const std::shared_ptr<RequestGroup>& item,
    DownloadEngine* e,
-   const std::vector<std::string>& keys) const;
+   const std::vector<std::string>& keys) const CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -432,13 +433,14 @@ public:
 class TellStoppedRpcMethod:
     public AbstractPaginationRpcMethod<DownloadResult> {
 protected:
-  virtual const DownloadResultList& getItems(DownloadEngine* e) const;
+  virtual const DownloadResultList& getItems(DownloadEngine* e) const
+    CXX11_OVERRIDE;
 
   virtual void createEntry
   (const std::shared_ptr<Dict>& entryDict,
    const std::shared_ptr<DownloadResult>& item,
    DownloadEngine* e,
-   const std::vector<std::string>& keys) const;
+   const std::vector<std::string>& keys) const CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -449,7 +451,7 @@ public:
 class ChangeOptionRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -460,7 +462,7 @@ public:
 class ChangeGlobalOptionRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -471,7 +473,7 @@ public:
 class GetVersionRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -482,7 +484,7 @@ public:
 class GetOptionRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -493,7 +495,7 @@ public:
 class GetGlobalOptionRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -504,7 +506,7 @@ public:
 class ChangePositionRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -515,7 +517,7 @@ public:
 class ChangeUriRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -526,7 +528,7 @@ public:
 class GetSessionInfoRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -537,7 +539,7 @@ public:
 class ShutdownRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -548,7 +550,7 @@ public:
 class GetGlobalStatRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -559,7 +561,7 @@ public:
 class ForceShutdownRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -570,7 +572,7 @@ public:
 class SystemMulticallRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 public:
   static const char* getMethodName()
   {
@@ -581,7 +583,7 @@ public:
 class NoSuchMethodRpcMethod:public RpcMethod {
 protected:
   virtual std::shared_ptr<ValueBase> process
-  (const RpcRequest& req, DownloadEngine* e);
+  (const RpcRequest& req, DownloadEngine* e) CXX11_OVERRIDE;
 };
 
 // Helper function to store data to entryDict from ds. This function
diff --git a/src/RpcResponse.cc b/src/RpcResponse.cc
index 5f5cab1a..a3c16655 100644
--- a/src/RpcResponse.cc
+++ b/src/RpcResponse.cc
@@ -59,21 +59,21 @@ void encodeValue(const std::shared_ptr<ValueBase>& value, OutputStream& o)
 
     virtual ~XmlValueBaseVisitor() {}
 
-    virtual void visit(const String& v)
+    virtual void visit(const String& v) CXX11_OVERRIDE
     {
       o_ << "<value><string>" << util::htmlEscape(v.s()) << "</string></value>";
     }
 
-    virtual void visit(const Integer& v)
+    virtual void visit(const Integer& v) CXX11_OVERRIDE
     {
       o_ << "<value><int>" << v.i() << "</int></value>";
     }
 
-    virtual void visit(const Bool& boolValue) {}
+    virtual void visit(const Bool& boolValue) CXX11_OVERRIDE {}
 
-    virtual void visit(const Null& nullValue) {}
+    virtual void visit(const Null& nullValue) CXX11_OVERRIDE {}
 
-    virtual void visit(const List& v)
+    virtual void visit(const List& v) CXX11_OVERRIDE
     {
       o_ << "<value><array><data>";
       for(List::ValueType::const_iterator i = v.begin(), eoi = v.end();
@@ -83,7 +83,7 @@ void encodeValue(const std::shared_ptr<ValueBase>& value, OutputStream& o)
       o_ << "</data></array></value>";
     }
 
-    virtual void visit(const Dict& v)
+    virtual void visit(const Dict& v) CXX11_OVERRIDE
     {
       o_ << "<value><struct>";
       for(Dict::ValueType::const_iterator i = v.begin(), eoi = v.end();
diff --git a/src/SaveSessionCommand.h b/src/SaveSessionCommand.h
index ab4d271f..fcd37bbc 100644
--- a/src/SaveSessionCommand.h
+++ b/src/SaveSessionCommand.h
@@ -46,9 +46,9 @@ public:
 
   virtual ~SaveSessionCommand();
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/SeedCheckCommand.h b/src/SeedCheckCommand.h
index 172a6190..fa2fb5f2 100644
--- a/src/SeedCheckCommand.h
+++ b/src/SeedCheckCommand.h
@@ -64,7 +64,7 @@ public:
 
   virtual ~SeedCheckCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void setBtRuntime(const std::shared_ptr<BtRuntime>& btRuntime);
 
diff --git a/src/SelectEventPoll.h b/src/SelectEventPoll.h
index 56623c00..0a7a4b54 100644
--- a/src/SelectEventPoll.h
+++ b/src/SelectEventPoll.h
@@ -186,19 +186,22 @@ public:
 
   virtual ~SelectEventPoll();
 
-  virtual void poll(const struct timeval& tv);
+  virtual void poll(const struct timeval& tv) CXX11_OVERRIDE;
 
   virtual bool addEvents(sock_t socket,
-                         Command* command, EventPoll::EventType events);
+                         Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 
   virtual bool deleteEvents(sock_t socket,
-                            Command* command, EventPoll::EventType events);
+                            Command* command, EventPoll::EventType events)
+    CXX11_OVERRIDE;
 #ifdef ENABLE_ASYNC_DNS
 
   virtual bool addNameResolver(const std::shared_ptr<AsyncNameResolver>& resolver,
-                               Command* command);
+                               Command* command) CXX11_OVERRIDE;
   virtual bool deleteNameResolver
-  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command);
+  (const std::shared_ptr<AsyncNameResolver>& resolver, Command* command)
+    CXX11_OVERRIDE;
 #endif // ENABLE_ASYNC_DNS
 };
 
diff --git a/src/SequentialDispatcherCommand.h b/src/SequentialDispatcherCommand.h
index 359807e2..ac4c7a6d 100644
--- a/src/SequentialDispatcherCommand.h
+++ b/src/SequentialDispatcherCommand.h
@@ -68,7 +68,7 @@ public:
     setStatusRealtime();
   }
 
-  virtual bool execute()
+  virtual bool execute() CXX11_OVERRIDE
   {
     if(e_->getRequestGroupMan()->downloadFinished() || e_->isHaltRequested()) {
       return true;
diff --git a/src/ShareRatioSeedCriteria.h b/src/ShareRatioSeedCriteria.h
index e61e2a66..e15e7557 100644
--- a/src/ShareRatioSeedCriteria.h
+++ b/src/ShareRatioSeedCriteria.h
@@ -57,9 +57,9 @@ public:
 
   virtual ~ShareRatioSeedCriteria();
 
-  virtual void reset();
+  virtual void reset() CXX11_OVERRIDE;
 
-  virtual bool evaluate();
+  virtual bool evaluate() CXX11_OVERRIDE;
 
   void setRatio(double ratio) {
     ratio_ = ratio;
diff --git a/src/SimpleBtMessage.h b/src/SimpleBtMessage.h
index f08bc904..0f7fdc37 100644
--- a/src/SimpleBtMessage.h
+++ b/src/SimpleBtMessage.h
@@ -45,7 +45,7 @@ class SimpleBtMessage : public AbstractBtMessage {
 public:
   SimpleBtMessage(uint8_t id, const char* name);
 
-  virtual void send();
+  virtual void send() CXX11_OVERRIDE;
 
   virtual unsigned char* createMessage() = 0;
 
diff --git a/src/SimpleRandomizer.h b/src/SimpleRandomizer.h
index f1670413..ffcb33ec 100644
--- a/src/SimpleRandomizer.h
+++ b/src/SimpleRandomizer.h
@@ -62,14 +62,14 @@ public:
 
   virtual ~SimpleRandomizer();
 
-  virtual long int getRandomNumber();
+  virtual long int getRandomNumber() CXX11_OVERRIDE;
 
-  virtual long int getMaxRandomNumber();
+  virtual long int getMaxRandomNumber() CXX11_OVERRIDE;
 
   /**
    * Returns random number in [0, to).
    */
-  virtual long int getRandomNumber(long int to);
+  virtual long int getRandomNumber(long int to) CXX11_OVERRIDE;
 
   long int operator()(long int to);
 };
diff --git a/src/SingleFileAllocationIterator.h b/src/SingleFileAllocationIterator.h
index 73eaf1d1..201baaf5 100644
--- a/src/SingleFileAllocationIterator.h
+++ b/src/SingleFileAllocationIterator.h
@@ -59,16 +59,16 @@ public:
 
   virtual ~SingleFileAllocationIterator();
 
-  virtual void allocateChunk();
+  virtual void allocateChunk() CXX11_OVERRIDE;
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
-  virtual int64_t getCurrentLength()
+  virtual int64_t getCurrentLength() CXX11_OVERRIDE
   {
     return offset_;
   }
 
-  virtual int64_t getTotalLength()
+  virtual int64_t getTotalLength() CXX11_OVERRIDE
   {
     return totalLength_;
   }
diff --git a/src/SinkStreamFilter.h b/src/SinkStreamFilter.h
index 5f428b12..ebb72c1a 100644
--- a/src/SinkStreamFilter.h
+++ b/src/SinkStreamFilter.h
@@ -49,28 +49,28 @@ private:
 public:
   SinkStreamFilter(WrDiskCache* wrDiskCache = 0, bool hashUpdate = false);
 
-  virtual void init() {}
+  virtual void init() CXX11_OVERRIDE {}
 
   virtual ssize_t transform
   (const std::shared_ptr<BinaryStream>& out,
    const std::shared_ptr<Segment>& segment,
-   const unsigned char* inbuf, size_t inlen);
+   const unsigned char* inbuf, size_t inlen) CXX11_OVERRIDE;
 
-  virtual bool finished()
+  virtual bool finished() CXX11_OVERRIDE
   {
     return true;
   }
 
-  virtual void release() {}
+  virtual void release() CXX11_OVERRIDE {}
 
-  virtual const std::string& getName() const
+  virtual const std::string& getName() const CXX11_OVERRIDE
   {
     return NAME;
   }
 
   static const std::string NAME;
 
-  virtual size_t getBytesProcessed() const
+  virtual size_t getBytesProcessed() const CXX11_OVERRIDE
   {
     return bytesProcessed_;
   }
diff --git a/src/SocketBuffer.h b/src/SocketBuffer.h
index 9a76e2b4..32d78287 100644
--- a/src/SocketBuffer.h
+++ b/src/SocketBuffer.h
@@ -78,10 +78,10 @@ private:
                       std::unique_ptr<ProgressUpdate> progressUpdate);
     virtual ~ByteArrayBufEntry();
     virtual ssize_t send
-    (const std::shared_ptr<SocketCore>& socket, size_t offset);
-    virtual bool final(size_t offset) const;
-    virtual size_t getLength() const;
-    virtual const unsigned char* getData() const;
+    (const std::shared_ptr<SocketCore>& socket, size_t offset) CXX11_OVERRIDE;
+    virtual bool final(size_t offset) const CXX11_OVERRIDE;
+    virtual size_t getLength() const CXX11_OVERRIDE;
+    virtual const unsigned char* getData() const CXX11_OVERRIDE;
   private:
     unsigned char* bytes_;
     size_t length_;
@@ -92,10 +92,10 @@ private:
     StringBufEntry(std::string s,
                    std::unique_ptr<ProgressUpdate> progressUpdate);
     virtual ssize_t send
-    (const std::shared_ptr<SocketCore>& socket, size_t offset);
-    virtual bool final(size_t offset) const;
-    virtual size_t getLength() const;
-    virtual const unsigned char* getData() const;
+    (const std::shared_ptr<SocketCore>& socket, size_t offset) CXX11_OVERRIDE;
+    virtual bool final(size_t offset) const CXX11_OVERRIDE;
+    virtual size_t getLength() const CXX11_OVERRIDE;
+    virtual const unsigned char* getData() const CXX11_OVERRIDE;
   private:
     std::string str_;
   };
diff --git a/src/Sqlite3CookieParserImpl.h b/src/Sqlite3CookieParserImpl.h
index 20a53d42..9a2e281e 100644
--- a/src/Sqlite3CookieParserImpl.h
+++ b/src/Sqlite3CookieParserImpl.h
@@ -44,7 +44,7 @@ public:
   Sqlite3MozCookieParser(const std::string& filename);
   virtual ~Sqlite3MozCookieParser();
 protected:
-  virtual const char* getQuery() const;
+  virtual const char* getQuery() const CXX11_OVERRIDE;
 };
 
 class Sqlite3ChromiumCookieParser:public Sqlite3CookieParser {
@@ -52,7 +52,7 @@ public:
   Sqlite3ChromiumCookieParser(const std::string& filename);
   virtual ~Sqlite3ChromiumCookieParser();
 protected:
-  virtual const char* getQuery() const;
+  virtual const char* getQuery() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/StreamCheckIntegrityEntry.h b/src/StreamCheckIntegrityEntry.h
index 8e880944..c4db1023 100644
--- a/src/StreamCheckIntegrityEntry.h
+++ b/src/StreamCheckIntegrityEntry.h
@@ -49,10 +49,12 @@ public:
   virtual ~StreamCheckIntegrityEntry();
 
   virtual void onDownloadFinished
-  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e);
+  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e)
+    CXX11_OVERRIDE;
 
   virtual void onDownloadIncomplete
-  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e);
+  (std::vector<std::unique_ptr<Command>>& commands, DownloadEngine* e)
+    CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/StreamFileAllocationEntry.h b/src/StreamFileAllocationEntry.h
index d4522b20..a689fcf4 100644
--- a/src/StreamFileAllocationEntry.h
+++ b/src/StreamFileAllocationEntry.h
@@ -49,7 +49,7 @@ public:
 
   virtual void prepareForNextAction
   (std::vector<std::unique_ptr<Command>>& commands,
-   DownloadEngine* e);
+   DownloadEngine* e) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/TimeBasedCommand.h b/src/TimeBasedCommand.h
index 967ebf9b..229c8ff8 100644
--- a/src/TimeBasedCommand.h
+++ b/src/TimeBasedCommand.h
@@ -99,7 +99,7 @@ public:
 
   virtual ~TimeBasedCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/TimeSeedCriteria.h b/src/TimeSeedCriteria.h
index 9dba4023..bc6bf9af 100644
--- a/src/TimeSeedCriteria.h
+++ b/src/TimeSeedCriteria.h
@@ -49,9 +49,9 @@ public:
   TimeSeedCriteria(time_t duration);
   virtual ~TimeSeedCriteria();
 
-  virtual void reset();
+  virtual void reset() CXX11_OVERRIDE;
 
-  virtual bool evaluate();
+  virtual bool evaluate() CXX11_OVERRIDE;
 
   void setDuration(time_t duration)
   {
diff --git a/src/TimedHaltCommand.h b/src/TimedHaltCommand.h
index c5052706..46329156 100644
--- a/src/TimedHaltCommand.h
+++ b/src/TimedHaltCommand.h
@@ -48,9 +48,9 @@ public:
 
   virtual ~TimedHaltCommand();
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/TrackerWatcherCommand.h b/src/TrackerWatcherCommand.h
index 63fa3cf9..2e6f20fa 100644
--- a/src/TrackerWatcherCommand.h
+++ b/src/TrackerWatcherCommand.h
@@ -72,11 +72,12 @@ class HTTPAnnRequest:public AnnRequest {
 public:
   HTTPAnnRequest(const std::shared_ptr<RequestGroup>& rg);
   virtual ~HTTPAnnRequest();
-  virtual bool stopped() const;
-  virtual bool success() const;
-  virtual bool issue(DownloadEngine* e);
-  virtual void stop(DownloadEngine* e);
-  virtual bool processResponse(const std::shared_ptr<BtAnnounce>& btAnnounce);
+  virtual bool stopped() const CXX11_OVERRIDE;
+  virtual bool success() const CXX11_OVERRIDE;
+  virtual bool issue(DownloadEngine* e) CXX11_OVERRIDE;
+  virtual void stop(DownloadEngine* e) CXX11_OVERRIDE;
+  virtual bool processResponse(const std::shared_ptr<BtAnnounce>& btAnnounce)
+    CXX11_OVERRIDE;
 private:
   std::shared_ptr<RequestGroup> rg_;
 };
@@ -85,11 +86,12 @@ class UDPAnnRequest:public AnnRequest {
 public:
   UDPAnnRequest(const std::shared_ptr<UDPTrackerRequest>& req);
   virtual ~UDPAnnRequest();
-  virtual bool stopped() const;
-  virtual bool success() const;
-  virtual bool issue(DownloadEngine* e);
-  virtual void stop(DownloadEngine* e);
-  virtual bool processResponse(const std::shared_ptr<BtAnnounce>& btAnnounce);
+  virtual bool stopped() const CXX11_OVERRIDE;
+  virtual bool success() const CXX11_OVERRIDE;
+  virtual bool issue(DownloadEngine* e) CXX11_OVERRIDE;
+  virtual void stop(DownloadEngine* e) CXX11_OVERRIDE;
+  virtual bool processResponse(const std::shared_ptr<BtAnnounce>& btAnnounce)
+    CXX11_OVERRIDE;
 private:
   std::shared_ptr<UDPTrackerRequest> req_;
 };
@@ -136,7 +138,7 @@ public:
 
   std::shared_ptr<AnnRequest> createAnnounce(DownloadEngine* e);
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void setPeerStorage(const std::shared_ptr<PeerStorage>& peerStorage);
 
diff --git a/src/TrueRequestGroupCriteria.h b/src/TrueRequestGroupCriteria.h
index 3f8e0911..d1a4d7a0 100644
--- a/src/TrueRequestGroupCriteria.h
+++ b/src/TrueRequestGroupCriteria.h
@@ -46,7 +46,7 @@ public:
 
   virtual ~TrueRequestGroupCriteria() {}
 
-  virtual bool match(const RequestGroup* requestGroup) const
+  virtual bool match(const RequestGroup* requestGroup) const CXX11_OVERRIDE
   {
     return true;
   }
diff --git a/src/TruncFileAllocationIterator.h b/src/TruncFileAllocationIterator.h
index 79c34d88..0ce43470 100644
--- a/src/TruncFileAllocationIterator.h
+++ b/src/TruncFileAllocationIterator.h
@@ -52,13 +52,13 @@ public:
   TruncFileAllocationIterator(BinaryStream* stream, int64_t offset,
                               int64_t totalLength);
 
-  virtual void allocateChunk();
+  virtual void allocateChunk() CXX11_OVERRIDE;
 
-  virtual bool finished();
+  virtual bool finished() CXX11_OVERRIDE;
 
-  virtual int64_t getCurrentLength();
+  virtual int64_t getCurrentLength() CXX11_OVERRIDE;
 
-  virtual int64_t getTotalLength();
+  virtual int64_t getTotalLength() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/UTMetadataDataExtensionMessage.h b/src/UTMetadataDataExtensionMessage.h
index 873d3f90..3c617d0b 100644
--- a/src/UTMetadataDataExtensionMessage.h
+++ b/src/UTMetadataDataExtensionMessage.h
@@ -59,11 +59,11 @@ private:
 public:
   UTMetadataDataExtensionMessage(uint8_t extensionMessageID);
 
-  virtual std::string getPayload();
+  virtual std::string getPayload() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
   void setTotalSize(size_t totalSize);
 
diff --git a/src/UTMetadataExtensionMessage.h b/src/UTMetadataExtensionMessage.h
index 70e27b15..866dbfe3 100644
--- a/src/UTMetadataExtensionMessage.h
+++ b/src/UTMetadataExtensionMessage.h
@@ -47,12 +47,12 @@ private:
 public:
   UTMetadataExtensionMessage(uint8_t extensionMessageID);
 
-  virtual uint8_t getExtensionMessageID() const
+  virtual uint8_t getExtensionMessageID() const CXX11_OVERRIDE
   {
     return extensionMessageID_;
   }
 
-  virtual const char* getExtensionName() const
+  virtual const char* getExtensionName() const CXX11_OVERRIDE
   {
     return EXTENSION_NAME;
   }
diff --git a/src/UTMetadataPostDownloadHandler.h b/src/UTMetadataPostDownloadHandler.h
index 54c40c9e..a0c3484d 100644
--- a/src/UTMetadataPostDownloadHandler.h
+++ b/src/UTMetadataPostDownloadHandler.h
@@ -46,14 +46,14 @@ private:
   class Criteria:public RequestGroupCriteria
   {
   public:
-    virtual bool match(const RequestGroup* requestGroup) const;
+    virtual bool match(const RequestGroup* requestGroup) const CXX11_OVERRIDE;
   };
 public:
   UTMetadataPostDownloadHandler();
 
   virtual void
   getNextRequestGroups(std::vector<std::shared_ptr<RequestGroup> >& groups,
-                       RequestGroup* requestGroup);
+                       RequestGroup* requestGroup) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/UTMetadataRejectExtensionMessage.h b/src/UTMetadataRejectExtensionMessage.h
index 6c596814..2bc820f5 100644
--- a/src/UTMetadataRejectExtensionMessage.h
+++ b/src/UTMetadataRejectExtensionMessage.h
@@ -43,11 +43,11 @@ class UTMetadataRejectExtensionMessage:public UTMetadataExtensionMessage {
 public:
   UTMetadataRejectExtensionMessage(uint8_t extensionMessageID);
 
-  virtual std::string getPayload();
+  virtual std::string getPayload() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/UTMetadataRequestExtensionMessage.h b/src/UTMetadataRequestExtensionMessage.h
index eaba6b3c..a59b9283 100644
--- a/src/UTMetadataRequestExtensionMessage.h
+++ b/src/UTMetadataRequestExtensionMessage.h
@@ -58,11 +58,11 @@ private:
 public:
   UTMetadataRequestExtensionMessage(uint8_t extensionMessageID);
 
-  virtual std::string getPayload();
+  virtual std::string getPayload() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
   void setDownloadContext(DownloadContext* dctx);
 
diff --git a/src/UTPexExtensionMessage.h b/src/UTPexExtensionMessage.h
index e977f9f6..1489a0f2 100644
--- a/src/UTPexExtensionMessage.h
+++ b/src/UTPexExtensionMessage.h
@@ -71,23 +71,23 @@ private:
 public:
   UTPexExtensionMessage(uint8_t extensionMessageID);
 
-  virtual std::string getPayload();
+  virtual std::string getPayload() CXX11_OVERRIDE;
 
-  virtual uint8_t getExtensionMessageID() const
+  virtual uint8_t getExtensionMessageID() const CXX11_OVERRIDE
   {
     return extensionMessageID_;
   }
 
-  virtual const char* getExtensionName() const
+  virtual const char* getExtensionName() const CXX11_OVERRIDE
   {
     return EXTENSION_NAME;
   }
 
   static const char EXTENSION_NAME[];
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 
-  virtual void doReceivedAction();
+  virtual void doReceivedAction() CXX11_OVERRIDE;
 
   bool addFreshPeer(const std::shared_ptr<Peer>& peer);
 
diff --git a/src/UnionSeedCriteria.h b/src/UnionSeedCriteria.h
index 68910ecf..a650b695 100644
--- a/src/UnionSeedCriteria.h
+++ b/src/UnionSeedCriteria.h
@@ -49,9 +49,9 @@ public:
   UnionSeedCriteria();
   virtual ~UnionSeedCriteria();
 
-  virtual void reset();
+  virtual void reset() CXX11_OVERRIDE;
 
-  virtual bool evaluate();
+  virtual bool evaluate() CXX11_OVERRIDE;
 
   void addSeedCriteria(std::unique_ptr<SeedCriteria> cri);
 
diff --git a/src/UnknownLengthPieceStorage.h b/src/UnknownLengthPieceStorage.h
index c7d232ed..f74adf03 100644
--- a/src/UnknownLengthPieceStorage.h
+++ b/src/UnknownLengthPieceStorage.h
@@ -68,45 +68,46 @@ public:
    * Returns true if the peer has a piece that localhost doesn't have.
    * Otherwise returns false.
    */
-  virtual bool hasMissingPiece(const std::shared_ptr<Peer>& peer);
+  virtual bool hasMissingPiece(const std::shared_ptr<Peer>& peer)
+    CXX11_OVERRIDE;
 
   virtual void getMissingPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual void getMissingPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual void getMissingFastPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual void getMissingFastPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<Piece> getMissingPiece
   (const std::shared_ptr<Peer>& peer,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   virtual std::shared_ptr<Piece> getMissingPiece
   (const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 #endif // ENABLE_BITTORRENT
 
-  virtual bool hasMissingUnusedPiece();
+  virtual bool hasMissingUnusedPiece() CXX11_OVERRIDE;
 
   /**
    * Returns a missing piece if available. Otherwise returns 0;
@@ -115,7 +116,7 @@ public:
   (size_t minSplitSize,
    const unsigned char* ignoreBitfield,
    size_t length,
-   cuid_t cuid);
+   cuid_t cuid) CXX11_OVERRIDE;
 
   /**
    * Returns a missing piece whose index is index.
@@ -123,63 +124,66 @@ public:
    * then returns 0.
    * Also returns 0 if any of missing piece is not available.
    */
-  virtual std::shared_ptr<Piece> getMissingPiece(size_t index, cuid_t cuid);
+  virtual std::shared_ptr<Piece> getMissingPiece(size_t index, cuid_t cuid)
+    CXX11_OVERRIDE;
 
   /**
    * Returns the piece denoted by index.
    * No status of the piece is changed in this method.
    */
-  virtual std::shared_ptr<Piece> getPiece(size_t index);
+  virtual std::shared_ptr<Piece> getPiece(size_t index) CXX11_OVERRIDE;
 
   /**
    * Tells that the download of the specfied piece completes.
    */
-  virtual void completePiece(const std::shared_ptr<Piece>& piece);
+  virtual void completePiece(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE;
 
   /**
    * Tells that the download of the specified piece is canceled.
    */
-  virtual void cancelPiece(const std::shared_ptr<Piece>& piece, cuid_t cuid);
+  virtual void cancelPiece(const std::shared_ptr<Piece>& piece, cuid_t cuid)
+    CXX11_OVERRIDE;
 
   /**
    * Returns true if the specified piece is already downloaded.
    * Otherwise returns false.
    */
-  virtual bool hasPiece(size_t index);
+  virtual bool hasPiece(size_t index) CXX11_OVERRIDE;
 
-  virtual bool isPieceUsed(size_t index);
+  virtual bool isPieceUsed(size_t index) CXX11_OVERRIDE;
 
-  virtual int64_t getTotalLength()
+  virtual int64_t getTotalLength() CXX11_OVERRIDE
   {
     return totalLength_;
   }
 
-  virtual int64_t getFilteredTotalLength()
+  virtual int64_t getFilteredTotalLength() CXX11_OVERRIDE
   {
     return totalLength_;
   }
 
-  virtual int64_t getCompletedLength()
+  virtual int64_t getCompletedLength() CXX11_OVERRIDE
   {
     // TODO we have to return actual completed length here?
     return totalLength_;
   }
 
-  virtual int64_t getFilteredCompletedLength()
+  virtual int64_t getFilteredCompletedLength() CXX11_OVERRIDE
   {
     return getCompletedLength();
   }
 
-  virtual void setupFileFilter() {}
+  virtual void setupFileFilter() CXX11_OVERRIDE {}
 
-  virtual void clearFileFilter() {}
+  virtual void clearFileFilter() CXX11_OVERRIDE {}
 
   /**
    * Returns true if download has completed.
    * If file filter is enabled, then returns true if those files have
    * downloaded.
    */
-  virtual bool downloadFinished()
+  virtual bool downloadFinished() CXX11_OVERRIDE
   {
     return downloadFinished_;
   }
@@ -188,7 +192,7 @@ public:
    * Returns true if all files have downloaded.
    * The file filter is ignored.
    */
-  virtual bool allDownloadFinished()
+  virtual bool allDownloadFinished() CXX11_OVERRIDE
   {
     return downloadFinished();
   }
@@ -197,48 +201,48 @@ public:
    * Initializes DiskAdaptor.
    * TODO add better documentation here.
    */
-  virtual void initStorage();
+  virtual void initStorage() CXX11_OVERRIDE;
 
-  virtual const unsigned char* getBitfield()
+  virtual const unsigned char* getBitfield() CXX11_OVERRIDE
   {
     return 0;
   }
 
   virtual void setBitfield(const unsigned char* bitfield,
-                           size_t bitfieldLength) {}
+                           size_t bitfieldLength) CXX11_OVERRIDE {}
 
-  virtual size_t getBitfieldLength()
+  virtual size_t getBitfieldLength() CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual bool isSelectiveDownloadingMode()
+  virtual bool isSelectiveDownloadingMode() CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual bool isEndGame()
+  virtual bool isEndGame() CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual void enterEndGame() {}
+  virtual void enterEndGame() CXX11_OVERRIDE {}
 
-  virtual void setEndGamePieceNum(size_t num) {}
+  virtual void setEndGamePieceNum(size_t num) CXX11_OVERRIDE {}
 
-  virtual std::shared_ptr<DiskAdaptor> getDiskAdaptor();
+  virtual std::shared_ptr<DiskAdaptor> getDiskAdaptor() CXX11_OVERRIDE;
 
-  virtual WrDiskCache* getWrDiskCache() { return 0; }
+  virtual WrDiskCache* getWrDiskCache() CXX11_OVERRIDE { return 0; }
 
-  virtual void flushWrDiskCacheEntry() {}
+  virtual void flushWrDiskCacheEntry() CXX11_OVERRIDE {}
 
-  virtual int32_t getPieceLength(size_t index);
+  virtual int32_t getPieceLength(size_t index) CXX11_OVERRIDE;
 
   /**
    * Adds piece index to advertise to other commands. They send have message
    * based on this information.
    */
-  virtual void advertisePiece(cuid_t cuid, size_t index) {}
+  virtual void advertisePiece(cuid_t cuid, size_t index) CXX11_OVERRIDE {}
 
   /**
    * Returns piece index which is not advertised by the caller command and
@@ -247,54 +251,58 @@ public:
   virtual void
   getAdvertisedPieceIndexes(std::vector<size_t>& indexes,
                             cuid_t myCuid, const Timer& lastCheckTime)
+    CXX11_OVERRIDE
   {}
 
   /**
    * Removes have entry if specified seconds have elapsed since its
    * registration.
    */
-  virtual void removeAdvertisedPiece(time_t elapsed) {}
+  virtual void removeAdvertisedPiece(time_t elapsed) CXX11_OVERRIDE {}
 
   /**
    * Sets all bits in bitfield to 1.
    */
-  virtual void markAllPiecesDone();
+  virtual void markAllPiecesDone() CXX11_OVERRIDE;
 
-  virtual void markPiecesDone(int64_t length);
+  virtual void markPiecesDone(int64_t length) CXX11_OVERRIDE;
 
-  virtual void markPieceMissing(size_t index);
+  virtual void markPieceMissing(size_t index) CXX11_OVERRIDE;
 
   /**
    * Do nothing because loading in-flight piece is not supported for this
    * class.
    */
   virtual void addInFlightPiece
-  (const std::vector<std::shared_ptr<Piece> >& pieces) {}
+  (const std::vector<std::shared_ptr<Piece> >& pieces) CXX11_OVERRIDE {}
 
-  virtual size_t countInFlightPiece()
+  virtual size_t countInFlightPiece() CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual void getInFlightPieces(std::vector<std::shared_ptr<Piece> >& pieces);
+  virtual void getInFlightPieces(std::vector<std::shared_ptr<Piece> >& pieces)
+    CXX11_OVERRIDE;
 
-  virtual void addPieceStats(size_t index) {}
+  virtual void addPieceStats(size_t index) CXX11_OVERRIDE {}
 
   virtual void addPieceStats(const unsigned char* bitfield,
-                             size_t bitfieldLength) {}
+                             size_t bitfieldLength) CXX11_OVERRIDE {}
 
   virtual void subtractPieceStats(const unsigned char* bitfield,
-                                  size_t bitfieldLength) {}
+                                  size_t bitfieldLength) CXX11_OVERRIDE {}
 
   virtual void updatePieceStats(const unsigned char* newBitfield,
                                 size_t newBitfieldLength,
-                                const unsigned char* oldBitfield) {}
+                                const unsigned char* oldBitfield)
+    CXX11_OVERRIDE
+  {}
 
-  virtual size_t getNextUsedIndex(size_t index) { return 0; }
+  virtual size_t getNextUsedIndex(size_t index) CXX11_OVERRIDE { return 0; }
 
   void setDiskWriterFactory(const std::shared_ptr<DiskWriterFactory>& diskWriterFactory);
 
-  virtual void onDownloadIncomplete() {}
+  virtual void onDownloadIncomplete() CXX11_OVERRIDE {}
 };
 
 } // namespace aria2
diff --git a/src/UnknownOptionException.h b/src/UnknownOptionException.h
index b6dd2e88..2500ac19 100644
--- a/src/UnknownOptionException.h
+++ b/src/UnknownOptionException.h
@@ -42,7 +42,7 @@ class UnknownOptionException:public RecoverableException {
 private:
   std::string unknownOption_;
 protected:
-  virtual std::shared_ptr<Exception> copy() const;
+  virtual std::shared_ptr<Exception> copy() const CXX11_OVERRIDE;
 public:
   UnknownOptionException(const char* file, int line,
                          const std::string& unknownOption);
diff --git a/src/ValueBase.h b/src/ValueBase.h
index c7986acf..115c1616 100644
--- a/src/ValueBase.h
+++ b/src/ValueBase.h
@@ -114,7 +114,7 @@ public:
     return std::shared_ptr<String>(new String(first, last));
   }
 
-  virtual void accept(ValueBaseVisitor& visitor) const;
+  virtual void accept(ValueBaseVisitor& visitor) const CXX11_OVERRIDE;
 private:
   ValueType str_;
 };
@@ -138,7 +138,7 @@ public:
 
   static std::shared_ptr<Integer> g(ValueType integer);
 
-  virtual void accept(ValueBaseVisitor& visitor) const;
+  virtual void accept(ValueBaseVisitor& visitor) const CXX11_OVERRIDE;
 private:
   ValueType integer_;
 };
@@ -148,7 +148,7 @@ public:
   static std::shared_ptr<Bool> gTrue();
   static std::shared_ptr<Bool> gFalse();
   bool val() const;
-  virtual void accept(ValueBaseVisitor& visitor) const;
+  virtual void accept(ValueBaseVisitor& visitor) const CXX11_OVERRIDE;
 private:
   Bool(bool val);
   // Don't allow copying
@@ -162,7 +162,7 @@ private:
 class Null:public ValueBase {
 public:
   static std::shared_ptr<Null> g();
-  virtual void accept(ValueBaseVisitor& visitor) const;
+  virtual void accept(ValueBaseVisitor& visitor) const CXX11_OVERRIDE;
 private:
   Null();
   // Don't allow copying
@@ -225,7 +225,7 @@ public:
 
   static std::shared_ptr<List> g();
 
-  virtual void accept(ValueBaseVisitor& visitor) const;
+  virtual void accept(ValueBaseVisitor& visitor) const CXX11_OVERRIDE;
 private:
   ValueType list_;
 };
@@ -291,7 +291,7 @@ public:
 
   static std::shared_ptr<Dict> g();
 
-  virtual void accept(ValueBaseVisitor& visitor) const;
+  virtual void accept(ValueBaseVisitor& visitor) const CXX11_OVERRIDE;
 private:
   ValueType dict_;
 };
@@ -299,12 +299,12 @@ private:
 class EmptyDowncastValueBaseVisitor:public ValueBaseVisitor {
 public:
   EmptyDowncastValueBaseVisitor() {}
-  virtual void visit(const String& v) {}
-  virtual void visit(const Integer& v) {}
-  virtual void visit(const Bool& v) {}
-  virtual void visit(const Null& v) {}
-  virtual void visit(const List& v) {}
-  virtual void visit(const Dict& v) {}
+  virtual void visit(const String& v) CXX11_OVERRIDE {}
+  virtual void visit(const Integer& v) CXX11_OVERRIDE {}
+  virtual void visit(const Bool& v) CXX11_OVERRIDE {}
+  virtual void visit(const Null& v) CXX11_OVERRIDE {}
+  virtual void visit(const List& v) CXX11_OVERRIDE {}
+  virtual void visit(const Dict& v) CXX11_OVERRIDE {}
 };
 
 template<typename T>
@@ -312,7 +312,7 @@ class DowncastValueBaseVisitor:public EmptyDowncastValueBaseVisitor {
 public:
   DowncastValueBaseVisitor():result_(0) {}
 
-  virtual void visit(const T& t)
+  virtual void visit(const T& t) CXX11_OVERRIDE
   {
     result_ = &t;
   }
diff --git a/src/ValueBaseDiskWriter.h b/src/ValueBaseDiskWriter.h
index 5c26ca83..c44389ab 100644
--- a/src/ValueBaseDiskWriter.h
+++ b/src/ValueBaseDiskWriter.h
@@ -54,35 +54,37 @@ public:
   virtual ~ValueBaseDiskWriter()
   {}
 
-  virtual void initAndOpenFile(int64_t totalLength = 0)
+  virtual void initAndOpenFile(int64_t totalLength = 0) CXX11_OVERRIDE
   {
     parser_.reset();
   }
 
-  virtual void openFile(int64_t totalLength = 0)
+  virtual void openFile(int64_t totalLength = 0) CXX11_OVERRIDE
   {
     initAndOpenFile(totalLength);
   }
 
-  virtual void closeFile() {}
+  virtual void closeFile() CXX11_OVERRIDE {}
 
-  virtual void openExistingFile(int64_t totalLength = 0)
+  virtual void openExistingFile(int64_t totalLength = 0) CXX11_OVERRIDE
   {
     initAndOpenFile(totalLength);
   }
 
-  virtual int64_t size()
+  virtual int64_t size() CXX11_OVERRIDE
   {
     return 0;
   }
 
   virtual void writeData(const unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE
   {
     // Return value is ignored here but handled in finalize()
     parser_.parseUpdate(reinterpret_cast<const char*>(data), len);
   }
 
   virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE
   {
     return 0;
   }
diff --git a/src/ValueBaseStructParserStateImpl.h b/src/ValueBaseStructParserStateImpl.h
index adef7f64..1956eb5c 100644
--- a/src/ValueBaseStructParserStateImpl.h
+++ b/src/ValueBaseStructParserStateImpl.h
@@ -44,10 +44,10 @@ public:
   virtual ~ValueValueBaseStructParserState() {}
 
   virtual void beginElement(ValueBaseStructParserStateMachine* psm,
-                            int elementType);
+                            int elementType) CXX11_OVERRIDE;
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType)
+                          int elementType) CXX11_OVERRIDE
   {}
 };
 
@@ -56,10 +56,10 @@ public:
   virtual ~DictValueBaseStructParserState() {}
 
   virtual void beginElement(ValueBaseStructParserStateMachine* psm,
-                            int elementType);
+                            int elementType) CXX11_OVERRIDE;
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType)
+                          int elementType) CXX11_OVERRIDE
   {}
 };
 
@@ -68,11 +68,11 @@ public:
   virtual ~DictKeyValueBaseStructParserState() {}
 
   virtual void beginElement(ValueBaseStructParserStateMachine* psm,
-                            int elementType)
+                            int elementType) CXX11_OVERRIDE
   {}
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType);
+                          int elementType) CXX11_OVERRIDE;
 };
 
 class DictDataValueBaseStructParserState :
@@ -81,7 +81,7 @@ public:
   virtual ~DictDataValueBaseStructParserState() {}
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType);
+                          int elementType) CXX11_OVERRIDE;
 };
 
 class ArrayValueBaseStructParserState : public ValueBaseStructParserState {
@@ -89,10 +89,10 @@ public:
   virtual ~ArrayValueBaseStructParserState() {}
 
   virtual void beginElement(ValueBaseStructParserStateMachine* psm,
-                            int elementType);
+                            int elementType) CXX11_OVERRIDE;
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType)
+                          int elementType) CXX11_OVERRIDE
   {}
 };
 
@@ -102,7 +102,7 @@ public:
   virtual ~ArrayDataValueBaseStructParserState() {}
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType);
+                          int elementType) CXX11_OVERRIDE;
 };
 
 class StringValueBaseStructParserState : public ValueBaseStructParserState {
@@ -110,11 +110,11 @@ public:
   virtual ~StringValueBaseStructParserState() {}
 
   virtual void beginElement(ValueBaseStructParserStateMachine* psm,
-                            int elementType)
+                            int elementType) CXX11_OVERRIDE
   {}
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType);
+                          int elementType) CXX11_OVERRIDE;
 };
 
 class NumberValueBaseStructParserState : public ValueBaseStructParserState {
@@ -122,11 +122,11 @@ public:
   virtual ~NumberValueBaseStructParserState() {}
 
   virtual void beginElement(ValueBaseStructParserStateMachine* psm,
-                            int elementType)
+                            int elementType) CXX11_OVERRIDE
   {}
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType);
+                          int elementType) CXX11_OVERRIDE;
 };
 
 class BoolValueBaseStructParserState : public ValueBaseStructParserState {
@@ -134,11 +134,11 @@ public:
   virtual ~BoolValueBaseStructParserState() {}
 
   virtual void beginElement(ValueBaseStructParserStateMachine* psm,
-                            int elementType)
+                            int elementType) CXX11_OVERRIDE
   {}
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType);
+                          int elementType) CXX11_OVERRIDE;
 };
 
 class NullValueBaseStructParserState : public ValueBaseStructParserState {
@@ -146,11 +146,11 @@ public:
   virtual ~NullValueBaseStructParserState() {}
 
   virtual void beginElement(ValueBaseStructParserStateMachine* psm,
-                            int elementType)
+                            int elementType) CXX11_OVERRIDE
   {}
 
   virtual void endElement(ValueBaseStructParserStateMachine* psm,
-                          int elementType);
+                          int elementType) CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/ValueBaseStructParserStateMachine.h b/src/ValueBaseStructParserStateMachine.h
index a0f0e6a5..38834438 100644
--- a/src/ValueBaseStructParserStateMachine.h
+++ b/src/ValueBaseStructParserStateMachine.h
@@ -73,16 +73,18 @@ public:
   ValueBaseStructParserStateMachine();
   virtual ~ValueBaseStructParserStateMachine();
 
-  virtual void beginElement(int elementType);
-  virtual void endElement(int elementType);
+  virtual void beginElement(int elementType) CXX11_OVERRIDE;
+  virtual void endElement(int elementType) CXX11_OVERRIDE;
 
-  virtual void charactersCallback(const char* data, size_t len);
-  virtual void numberCallback(int64_t number, int frac, int exp);
-  virtual void boolCallback(bool bval);
+  virtual void charactersCallback(const char* data, size_t len)
+    CXX11_OVERRIDE;
+  virtual void numberCallback(int64_t number, int frac, int exp)
+    CXX11_OVERRIDE;
+  virtual void boolCallback(bool bval) CXX11_OVERRIDE;
 
   std::shared_ptr<ValueBase> getResult() const;
 
-  virtual void reset();
+  virtual void reset() CXX11_OVERRIDE;
 
   const std::string& getCharacters() const;
   const NumberData& getNumber() const;
diff --git a/src/WatchProcessCommand.h b/src/WatchProcessCommand.h
index e03833c4..7976d004 100644
--- a/src/WatchProcessCommand.h
+++ b/src/WatchProcessCommand.h
@@ -49,9 +49,9 @@ public:
    unsigned int pid,
    bool forceHalt = false);
 
-  virtual void preProcess();
+  virtual void preProcess() CXX11_OVERRIDE;
 
-  virtual void process();
+  virtual void process() CXX11_OVERRIDE;
 private:
   unsigned int pid_;
   bool forceHalt_;
diff --git a/src/WebSocketInteractionCommand.h b/src/WebSocketInteractionCommand.h
index 4b1acf73..ce7f7723 100644
--- a/src/WebSocketInteractionCommand.h
+++ b/src/WebSocketInteractionCommand.h
@@ -62,7 +62,7 @@ public:
 
   virtual ~WebSocketInteractionCommand();
 
-  virtual bool execute();
+  virtual bool execute() CXX11_OVERRIDE;
 
   void updateWriteCheck();
 };
diff --git a/src/WebSocketResponseCommand.h b/src/WebSocketResponseCommand.h
index b570a5d0..24b21ffa 100644
--- a/src/WebSocketResponseCommand.h
+++ b/src/WebSocketResponseCommand.h
@@ -44,7 +44,7 @@ namespace rpc {
 class WebSocketResponseCommand : public AbstractHttpServerResponseCommand {
 protected:
   virtual void afterSend(const std::shared_ptr<HttpServer>& httpServer,
-                         DownloadEngine* e);
+                         DownloadEngine* e) CXX11_OVERRIDE;
 public:
   WebSocketResponseCommand(cuid_t cuid,
                            const std::shared_ptr<HttpServer>& httpServer,
diff --git a/src/WebSocketSessionMan.h b/src/WebSocketSessionMan.h
index d32654c0..1081bf8b 100644
--- a/src/WebSocketSessionMan.h
+++ b/src/WebSocketSessionMan.h
@@ -60,7 +60,8 @@ public:
   void addSession(const std::shared_ptr<WebSocketSession>& wsSession);
   void removeSession(const std::shared_ptr<WebSocketSession>& wsSession);
   void addNotification(const std::string& method, const RequestGroup* group);
-  virtual void onEvent(DownloadEvent event, const RequestGroup* group);
+  virtual void onEvent(DownloadEvent event, const RequestGroup* group)
+    CXX11_OVERRIDE;
 private:
   WebSocketSessions sessions_;
 };
diff --git a/src/WinConsoleFile.h b/src/WinConsoleFile.h
index b39d292e..ec6f8e26 100644
--- a/src/WinConsoleFile.h
+++ b/src/WinConsoleFile.h
@@ -44,10 +44,10 @@ class WinConsoleFile:public OutputFile {
 public:
   WinConsoleFile(DWORD stdHandle);
   virtual ~WinConsoleFile();
-  virtual size_t write(const char* str);
-  virtual int vprintf(const char* format, va_list va);
-  virtual int flush();
-  virtual bool supportsColor();
+  virtual size_t write(const char* str) CXX11_OVERRIDE;
+  virtual int vprintf(const char* format, va_list va) CXX11_OVERRIDE;
+  virtual int flush() CXX11_OVERRIDE;
+  virtual bool supportsColor() CXX11_OVERRIDE;
 private:
   DWORD stdHandle_;
   // Don't allow copying
diff --git a/src/XmlRpcDiskWriter.h b/src/XmlRpcDiskWriter.h
index 93d3f83c..b40cdc55 100644
--- a/src/XmlRpcDiskWriter.h
+++ b/src/XmlRpcDiskWriter.h
@@ -54,28 +54,30 @@ public:
 
   virtual ~XmlRpcDiskWriter();
 
-  virtual void initAndOpenFile(int64_t totalLength = 0);
+  virtual void initAndOpenFile(int64_t totalLength = 0) CXX11_OVERRIDE;
 
-  virtual void openFile(int64_t totalLength = 0)
+  virtual void openFile(int64_t totalLength = 0) CXX11_OVERRIDE
   {
     initAndOpenFile(totalLength);
   }
 
-  virtual void closeFile() {}
+  virtual void closeFile() CXX11_OVERRIDE {}
 
-  virtual void openExistingFile(int64_t totalLength = 0)
+  virtual void openExistingFile(int64_t totalLength = 0) CXX11_OVERRIDE
   {
     initAndOpenFile(totalLength);
   }
 
-  virtual int64_t size()
+  virtual int64_t size() CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual void writeData(const unsigned char* data, size_t len, int64_t offset);
+  virtual void writeData(const unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE;
 
   virtual ssize_t readData(unsigned char* data, size_t len, int64_t offset)
+    CXX11_OVERRIDE
   {
     return 0;
   }
diff --git a/src/XmlRpcRequestParserStateImpl.h b/src/XmlRpcRequestParserStateImpl.h
index e2bfd5c5..a9aa0b46 100644
--- a/src/XmlRpcRequestParserStateImpl.h
+++ b/src/XmlRpcRequestParserStateImpl.h
@@ -45,190 +45,199 @@ class InitialXmlRpcRequestParserState:public XmlRpcRequestParserState {
 public:
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class UnknownElementXmlRpcRequestParserState:public XmlRpcRequestParserState {
 public:
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters) {}
+                          const std::string& characters) CXX11_OVERRIDE {}
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class MethodCallXmlRpcRequestParserState:public XmlRpcRequestParserState {
 public:
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters) {}
+                          const std::string& characters) CXX11_OVERRIDE {}
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class MethodNameXmlRpcRequestParserState:public XmlRpcRequestParserState {
 public:
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return true; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE { return true; }
 };
 
 class ParamsXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters) {}
+                          const std::string& characters) CXX11_OVERRIDE {}
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class ParamXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class ValueXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 protected:
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return true; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE { return true; }
 };
 
 class IntXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return true; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE { return true; }
 };
 
 class StringXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return true; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE { return true; }
 };
 
 class Base64XmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return true; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE { return true; }
 };
 
 class StructXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters) {}
+                          const std::string& characters) CXX11_OVERRIDE {}
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class MemberXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class NameXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 
-  virtual bool needsCharactersBuffering() const { return true; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE { return true; }
 };
 
 class ArrayXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters) {}
+                          const std::string& characters) CXX11_OVERRIDE {}
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class DataXmlRpcRequestParserState:public XmlRpcRequestParserState {
   virtual void beginElement(XmlRpcRequestParserStateMachine* psm,
                             const char* name,
-                            const std::vector<XmlAttr>& attrs);
+                            const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters) {}
+                          const std::string& characters) CXX11_OVERRIDE {}
 
-  virtual bool needsCharactersBuffering() const { return false; }
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE
+  { return false; }
 };
 
 class ArrayValueXmlRpcRequestParserState:public ValueXmlRpcRequestParserState {
   virtual void endElement(XmlRpcRequestParserStateMachine* psm,
                           const char* name,
-                          const std::string& characters);
+                          const std::string& characters) CXX11_OVERRIDE;
 };
 
 } // namespace rpc
diff --git a/src/XmlRpcRequestParserStateMachine.h b/src/XmlRpcRequestParserStateMachine.h
index 7116df9f..2fb423c4 100644
--- a/src/XmlRpcRequestParserStateMachine.h
+++ b/src/XmlRpcRequestParserStateMachine.h
@@ -55,22 +55,22 @@ public:
   XmlRpcRequestParserStateMachine();
   virtual ~XmlRpcRequestParserStateMachine();
 
-  virtual bool needsCharactersBuffering() const;
-  virtual bool finished() const;
+  virtual bool needsCharactersBuffering() const CXX11_OVERRIDE;
+  virtual bool finished() const CXX11_OVERRIDE;
 
   virtual void beginElement
   (const char* localname,
    const char* prefix,
    const char* nsUri,
-   const std::vector<XmlAttr>& attrs);
+   const std::vector<XmlAttr>& attrs) CXX11_OVERRIDE;
 
   virtual void endElement
   (const char* localname,
    const char* prefix,
    const char* nsUri,
-   const std::string& characters);
+   const std::string& characters) CXX11_OVERRIDE;
 
-  virtual void reset();
+  virtual void reset() CXX11_OVERRIDE;
 
   void setMethodName(const std::string& methodName);
   const std::string& getMethodName() const;
diff --git a/src/ZeroBtMessage.h b/src/ZeroBtMessage.h
index 223d3d68..c1389d7d 100644
--- a/src/ZeroBtMessage.h
+++ b/src/ZeroBtMessage.h
@@ -56,11 +56,11 @@ protected:
 public:
   ZeroBtMessage(uint8_t id, const char* name);
 
-  virtual unsigned char* createMessage();
+  virtual unsigned char* createMessage() CXX11_OVERRIDE;
 
-  virtual size_t getMessageLength();
+  virtual size_t getMessageLength() CXX11_OVERRIDE;
 
-  virtual std::string toString() const;
+  virtual std::string toString() const CXX11_OVERRIDE;
 };
 
 } // namespace aria2
diff --git a/src/aria2api.cc b/src/aria2api.cc
index 0443ebfb..c3833bff 100644
--- a/src/aria2api.cc
+++ b/src/aria2api.cc
@@ -691,7 +691,7 @@ struct RequestGroupDH : public DownloadHandle {
       ts(group->calculateStat())
   {}
   virtual ~RequestGroupDH() {}
-  virtual DownloadStatus getStatus()
+  virtual DownloadStatus getStatus() CXX11_OVERRIDE
   {
     if(group->getState() == RequestGroup::STATE_ACTIVE) {
       return DOWNLOAD_ACTIVE;
@@ -703,19 +703,19 @@ struct RequestGroupDH : public DownloadHandle {
       }
     }
   }
-  virtual int64_t getTotalLength()
+  virtual int64_t getTotalLength() CXX11_OVERRIDE
   {
     return group->getTotalLength();
   }
-  virtual int64_t getCompletedLength()
+  virtual int64_t getCompletedLength() CXX11_OVERRIDE
   {
     return group->getCompletedLength();
   }
-  virtual int64_t getUploadLength()
+  virtual int64_t getUploadLength() CXX11_OVERRIDE
   {
     return ts.allTimeUploadLength;
   }
-  virtual std::string getBitfield()
+  virtual std::string getBitfield() CXX11_OVERRIDE
   {
     const std::shared_ptr<PieceStorage>& ps = group->getPieceStorage();
     if(ps) {
@@ -725,15 +725,15 @@ struct RequestGroupDH : public DownloadHandle {
       return "";
     }
   }
-  virtual int getDownloadSpeed()
+  virtual int getDownloadSpeed() CXX11_OVERRIDE
   {
     return ts.downloadSpeed;
   }
-  virtual int getUploadSpeed()
+  virtual int getUploadSpeed() CXX11_OVERRIDE
   {
     return ts.uploadSpeed;
   }
-  virtual const std::string& getInfoHash()
+  virtual const std::string& getInfoHash() CXX11_OVERRIDE
   {
 #ifdef ENABLE_BITTORRENT
     if(group->getDownloadContext()->hasAttribute(CTX_ATTR_BT)) {
@@ -743,36 +743,36 @@ struct RequestGroupDH : public DownloadHandle {
 #endif // ENABLE_BITTORRENT
     return A2STR::NIL;
   }
-  virtual size_t getPieceLength()
+  virtual size_t getPieceLength() CXX11_OVERRIDE
   {
     const std::shared_ptr<DownloadContext>& dctx = group->getDownloadContext();
     return dctx->getPieceLength();
   }
-  virtual int getNumPieces()
+  virtual int getNumPieces() CXX11_OVERRIDE
   {
     return group->getDownloadContext()->getNumPieces();
   }
-  virtual int getConnections()
+  virtual int getConnections() CXX11_OVERRIDE
   {
     return group->getNumConnection();
   }
-  virtual int getErrorCode()
+  virtual int getErrorCode() CXX11_OVERRIDE
   {
     return 0;
   }
-  virtual const std::vector<A2Gid>& getFollowedBy()
+  virtual const std::vector<A2Gid>& getFollowedBy() CXX11_OVERRIDE
   {
     return group->followedBy();
   }
-  virtual A2Gid getBelongsTo()
+  virtual A2Gid getBelongsTo() CXX11_OVERRIDE
   {
     return group->belongsTo();
   }
-  virtual const std::string& getDir()
+  virtual const std::string& getDir() CXX11_OVERRIDE
   {
     return group->getOption()->get(PREF_DIR);
   }
-  virtual std::vector<FileData> getFiles()
+  virtual std::vector<FileData> getFiles() CXX11_OVERRIDE
   {
     std::vector<FileData> res;
     const std::shared_ptr<DownloadContext>& dctx = group->getDownloadContext();
@@ -783,12 +783,12 @@ struct RequestGroupDH : public DownloadHandle {
                     group->getPieceStorage());
     return res;
   }
-  virtual int getNumFiles()
+  virtual int getNumFiles() CXX11_OVERRIDE
   {
     const std::shared_ptr<DownloadContext>& dctx = group->getDownloadContext();
     return dctx->getFileEntries().size();
   }
-  virtual FileData getFile(int index)
+  virtual FileData getFile(int index) CXX11_OVERRIDE
   {
     const std::shared_ptr<DownloadContext>& dctx = group->getDownloadContext();
     BitfieldMan bf(dctx->getPieceLength(), dctx->getTotalLength());
@@ -798,7 +798,7 @@ struct RequestGroupDH : public DownloadHandle {
     }
     return createFileData(dctx->getFileEntries()[index-1], index, &bf);
   }
-  virtual BtMetaInfoData getBtMetaInfo()
+  virtual BtMetaInfoData getBtMetaInfo() CXX11_OVERRIDE
   {
     BtMetaInfoData res;
 #ifdef ENABLE_BITTORRENT
@@ -820,11 +820,11 @@ struct RequestGroupDH : public DownloadHandle {
       }
     return res;
   }
-  virtual const std::string& getOption(const std::string& name)
+  virtual const std::string& getOption(const std::string& name) CXX11_OVERRIDE
   {
     return getRequestOption(group->getOption(), name);
   }
-  virtual KeyVals getOptions()
+  virtual KeyVals getOptions() CXX11_OVERRIDE
   {
     return getRequestOptions(group->getOption());
   }
@@ -839,7 +839,7 @@ struct DownloadResultDH : public DownloadHandle {
     : dr(dr)
   {}
   virtual ~DownloadResultDH() {}
-  virtual DownloadStatus getStatus()
+  virtual DownloadStatus getStatus() CXX11_OVERRIDE
   {
     switch(dr->result) {
     case error_code::FINISHED:
@@ -850,63 +850,63 @@ struct DownloadResultDH : public DownloadHandle {
       return DOWNLOAD_ERROR;
     }
   }
-  virtual int64_t getTotalLength()
+  virtual int64_t getTotalLength() CXX11_OVERRIDE
   {
     return dr->totalLength;
   }
-  virtual int64_t getCompletedLength()
+  virtual int64_t getCompletedLength() CXX11_OVERRIDE
   {
     return dr->completedLength;
   }
-  virtual int64_t getUploadLength()
+  virtual int64_t getUploadLength() CXX11_OVERRIDE
   {
     return dr->uploadLength;
   }
-  virtual std::string getBitfield()
+  virtual std::string getBitfield() CXX11_OVERRIDE
   {
     return dr->bitfield;
   }
-  virtual int getDownloadSpeed()
+  virtual int getDownloadSpeed() CXX11_OVERRIDE
   {
     return 0;
   }
-  virtual int getUploadSpeed()
+  virtual int getUploadSpeed() CXX11_OVERRIDE
   {
     return 0;
   }
-  virtual const std::string& getInfoHash()
+  virtual const std::string& getInfoHash() CXX11_OVERRIDE
   {
     return dr->infoHash;
   }
-  virtual size_t getPieceLength()
+  virtual size_t getPieceLength() CXX11_OVERRIDE
   {
     return dr->pieceLength;
   }
-  virtual int getNumPieces()
+  virtual int getNumPieces() CXX11_OVERRIDE
   {
     return dr->numPieces;
   }
-  virtual int getConnections()
+  virtual int getConnections() CXX11_OVERRIDE
   {
     return 0;
   }
-  virtual int getErrorCode()
+  virtual int getErrorCode() CXX11_OVERRIDE
   {
     return dr->result;
   }
-  virtual const std::vector<A2Gid>& getFollowedBy()
+  virtual const std::vector<A2Gid>& getFollowedBy() CXX11_OVERRIDE
   {
     return dr->followedBy;
   }
-  virtual A2Gid getBelongsTo()
+  virtual A2Gid getBelongsTo() CXX11_OVERRIDE
   {
     return dr->belongsTo;
   }
-  virtual const std::string& getDir()
+  virtual const std::string& getDir() CXX11_OVERRIDE
   {
     return dr->dir;
   }
-  virtual std::vector<FileData> getFiles()
+  virtual std::vector<FileData> getFiles() CXX11_OVERRIDE
   {
     std::vector<FileData> res;
     createFileEntry(std::back_inserter(res),
@@ -914,26 +914,26 @@ struct DownloadResultDH : public DownloadHandle {
                     dr->totalLength, dr->pieceLength, dr->bitfield);
     return res;
   }
-  virtual int getNumFiles()
+  virtual int getNumFiles() CXX11_OVERRIDE
   {
     return dr->fileEntries.size();
   }
-  virtual FileData getFile(int index)
+  virtual FileData getFile(int index) CXX11_OVERRIDE
   {
     BitfieldMan bf(dr->pieceLength, dr->totalLength);
     bf.setBitfield(reinterpret_cast<const unsigned char*>(dr->bitfield.data()),
                    dr->bitfield.size());
     return createFileData(dr->fileEntries[index-1], index, &bf);
   }
-  virtual BtMetaInfoData getBtMetaInfo()
+  virtual BtMetaInfoData getBtMetaInfo() CXX11_OVERRIDE
   {
     return BtMetaInfoData();
   }
-  virtual const std::string& getOption(const std::string& name)
+  virtual const std::string& getOption(const std::string& name) CXX11_OVERRIDE
   {
     return getRequestOption(dr->option, name);
   }
-  virtual KeyVals getOptions()
+  virtual KeyVals getOptions() CXX11_OVERRIDE
   {
     return getRequestOptions(dr->option);
   }
diff --git a/src/bencode2.cc b/src/bencode2.cc
index 00bb2a78..81b14403 100644
--- a/src/bencode2.cc
+++ b/src/bencode2.cc
@@ -82,22 +82,22 @@ std::string encode(const ValueBase* vlb)
   private:
     std::ostringstream out_;
   public:
-    virtual void visit(const String& string)
+    virtual void visit(const String& string) CXX11_OVERRIDE
     {
       const std::string& s = string.s();
       out_ << s.size() << ":";
       out_.write(s.data(), s.size());
     }
 
-    virtual void visit(const Integer& integer)
+    virtual void visit(const Integer& integer) CXX11_OVERRIDE
     {
       out_ << "i" << integer.i() << "e";
     }
 
-    virtual void visit(const Bool& v) {}
-    virtual void visit(const Null& v) {}
+    virtual void visit(const Bool& v) CXX11_OVERRIDE {}
+    virtual void visit(const Null& v) CXX11_OVERRIDE {}
 
-    virtual void visit(const List& list)
+    virtual void visit(const List& list) CXX11_OVERRIDE
     {
       out_ << "l";
       for(List::ValueType::const_iterator i = list.begin(), eoi = list.end();
@@ -107,7 +107,7 @@ std::string encode(const ValueBase* vlb)
       out_ << "e";
     }
 
-    virtual void visit(const Dict& dict)
+    virtual void visit(const Dict& dict) CXX11_OVERRIDE
     {
       out_ << "d";
       for(Dict::ValueType::const_iterator i = dict.begin(), eoi = dict.end();
diff --git a/src/bittorrent_helper.cc b/src/bittorrent_helper.cc
index b4f26d65..238d2c0e 100644
--- a/src/bittorrent_helper.cc
+++ b/src/bittorrent_helper.cc
@@ -141,18 +141,18 @@ void extractUrlList
     (std::vector<std::string>& uris, TorrentAttribute* torrent):
       uris_(uris), torrent_(torrent) {}
 
-    virtual void visit(const String& v)
+    virtual void visit(const String& v) CXX11_OVERRIDE
     {
       std::string utf8Uri = util::encodeNonUtf8(v.s());
       uris_.push_back(utf8Uri);
       torrent_->urlList.push_back(utf8Uri);
     }
 
-    virtual void visit(const Integer& v) {}
-    virtual void visit(const Bool& v) {}
-    virtual void visit(const Null& v) {}
+    virtual void visit(const Integer& v) CXX11_OVERRIDE {}
+    virtual void visit(const Bool& v) CXX11_OVERRIDE {}
+    virtual void visit(const Null& v) CXX11_OVERRIDE {}
 
-    virtual void visit(const List& v)
+    virtual void visit(const List& v) CXX11_OVERRIDE
     {
       for(List::ValueType::const_iterator itr = v.begin(), eoi = v.end();
           itr != eoi; ++itr) {
@@ -164,7 +164,7 @@ void extractUrlList
         }
       }
     }
-    virtual void visit(const Dict& v) {}
+    virtual void visit(const Dict& v) CXX11_OVERRIDE {}
   };
 
   if(v) {
diff --git a/src/bittorrent_helper.h b/src/bittorrent_helper.h
index 19647b42..d6d93400 100644
--- a/src/bittorrent_helper.h
+++ b/src/bittorrent_helper.h
@@ -278,7 +278,7 @@ void extractPeer(const ValueBase* peerData, int family, OutputIterator dest)
 
     virtual ~PeerListValueBaseVisitor() {}
 
-    virtual void visit(const String& peerData)
+    virtual void visit(const String& peerData) CXX11_OVERRIDE
     {
       int unit = family_ == AF_INET?6:18;
       size_t length = peerData.s().size();
@@ -296,11 +296,11 @@ void extractPeer(const ValueBase* peerData, int family, OutputIterator dest)
       }
     }
 
-    virtual void visit(const Integer& v) {}
-    virtual void visit(const Bool& v) {}
-    virtual void visit(const Null& v) {}
+    virtual void visit(const Integer& v) CXX11_OVERRIDE {}
+    virtual void visit(const Bool& v) CXX11_OVERRIDE {}
+    virtual void visit(const Null& v) CXX11_OVERRIDE {}
 
-    virtual void visit(const List& peerData)
+    virtual void visit(const List& peerData) CXX11_OVERRIDE
     {
       for(List::ValueType::const_iterator itr = peerData.begin(),
             eoi = peerData.end(); itr != eoi; ++itr) {
@@ -320,7 +320,7 @@ void extractPeer(const ValueBase* peerData, int family, OutputIterator dest)
       }
     }
 
-    virtual void visit(const Dict& v) {}
+    virtual void visit(const Dict& v) CXX11_OVERRIDE {}
   };
   if(peerData) {
     PeerListValueBaseVisitor visitor(dest, family);
diff --git a/src/json.h b/src/json.h
index fa2e07ee..9d9cf7f7 100644
--- a/src/json.h
+++ b/src/json.h
@@ -51,27 +51,27 @@ OutputStream& encode(OutputStream& out, const ValueBase* vlb)
   public:
     JsonValueBaseVisitor(OutputStream& out):out_(out) {}
 
-    virtual void visit(const String& string)
+    virtual void visit(const String& string) CXX11_OVERRIDE
     {
       encodeString(string.s());
     }
 
-    virtual void visit(const Integer& integer)
+    virtual void visit(const Integer& integer) CXX11_OVERRIDE
     {
       out_ << integer.i();
     }
 
-    virtual void visit(const Bool& boolValue)
+    virtual void visit(const Bool& boolValue) CXX11_OVERRIDE
     {
       out_ << (boolValue.val() ? "true" : "false");
     }
 
-    virtual void visit(const Null& nullValue)
+    virtual void visit(const Null& nullValue) CXX11_OVERRIDE
     {
       out_ << "null";
     }
 
-    virtual void visit(const List& list)
+    virtual void visit(const List& list) CXX11_OVERRIDE
     {
       out_ << "[";
       List::ValueType::const_iterator i = list.begin();
@@ -86,7 +86,7 @@ OutputStream& encode(OutputStream& out, const ValueBase* vlb)
       out_ << "]";
     }
 
-    virtual void visit(const Dict& dict)
+    virtual void visit(const Dict& dict) CXX11_OVERRIDE
     {
       out_ << "{";
       Dict::ValueType::const_iterator i = dict.begin();
diff --git a/test/BtPieceMessageTest.cc b/test/BtPieceMessageTest.cc
index 285ba21f..77ef609f 100644
--- a/test/BtPieceMessageTest.cc
+++ b/test/BtPieceMessageTest.cc
@@ -53,7 +53,8 @@ public:
     virtual std::unique_ptr<BtRejectMessage>
     createRejectMessage(size_t index,
                         int32_t begin,
-                        int32_t length) {
+                        int32_t length) CXX11_OVERRIDE
+    {
       return make_unique<BtRejectMessage>(index, begin, length);
     }
   };
diff --git a/test/BtPortMessageTest.cc b/test/BtPortMessageTest.cc
index a2675b59..4a3dda34 100644
--- a/test/BtPortMessageTest.cc
+++ b/test/BtPortMessageTest.cc
@@ -41,12 +41,13 @@ public:
   public:
     virtual std::shared_ptr<DHTTask>
     createPingTask(const std::shared_ptr<DHTNode>& remoteNode, int numRetry)
+      CXX11_OVERRIDE
     {
       return std::shared_ptr<DHTTask>(new MockDHTTask(remoteNode));
     }
 
     virtual std::shared_ptr<DHTTask>
-    createNodeLookupTask(const unsigned char* targetID)
+    createNodeLookupTask(const unsigned char* targetID) CXX11_OVERRIDE
     {
       std::shared_ptr<MockDHTTask> task(new MockDHTTask(std::shared_ptr<DHTNode>()));
       task->setTargetID(targetID);
diff --git a/test/FixedNumberRandomizer.h b/test/FixedNumberRandomizer.h
index 0e3be223..e2579fb9 100644
--- a/test/FixedNumberRandomizer.h
+++ b/test/FixedNumberRandomizer.h
@@ -14,15 +14,15 @@ public:
 
   virtual ~FixedNumberRandomizer() {}
 
-  virtual long int getRandomNumber() {
+  virtual long int getRandomNumber() CXX11_OVERRIDE {
     return fixedNumber;
   }
 
-  virtual long int getMaxRandomNumber() {
+  virtual long int getMaxRandomNumber() CXX11_OVERRIDE {
     return RAND_MAX;
   }
 
-  virtual long int getRandomNumber(long int to)
+  virtual long int getRandomNumber(long int to) CXX11_OVERRIDE
   {
     return getRandomNumber();
   }
diff --git a/test/InorderPieceSelector.h b/test/InorderPieceSelector.h
index a84f78ee..f9aa13cc 100644
--- a/test/InorderPieceSelector.h
+++ b/test/InorderPieceSelector.h
@@ -10,6 +10,7 @@ class InorderPieceSelector:public PieceSelector {
 public:
   virtual bool select
   (size_t& index, const unsigned char* bitfield, size_t nbits) const
+    CXX11_OVERRIDE
   {
     for(size_t i = 0; i < nbits; ++i) {
       if(bitfield::test(bitfield, nbits, i)) {
diff --git a/test/MockBtAnnounce.h b/test/MockBtAnnounce.h
index 170d6e44..c72ace14 100644
--- a/test/MockBtAnnounce.h
+++ b/test/MockBtAnnounce.h
@@ -14,7 +14,7 @@ public:
   MockBtAnnounce() {}
   virtual ~MockBtAnnounce() {}
 
-  virtual bool isAnnounceReady() {
+  virtual bool isAnnounceReady() CXX11_OVERRIDE {
     return announceReady;
   }
 
@@ -22,13 +22,13 @@ public:
     this->announceReady = flag;
   }
 
-  virtual std::string getAnnounceUrl() {
+  virtual std::string getAnnounceUrl() CXX11_OVERRIDE {
     return announceUrl;
   }
 
   virtual std::shared_ptr<UDPTrackerRequest>
   createUDPTrackerRequest(const std::string& remoteAddr, uint16_t remotePort,
-                          uint16_t localPort) {
+                          uint16_t localPort) CXX11_OVERRIDE {
     return nullptr;
   }
 
@@ -36,38 +36,36 @@ public:
     this->announceUrl = url;
   }
 
-  virtual void announceStart() {}
+  virtual void announceStart() CXX11_OVERRIDE {}
 
-  virtual void announceSuccess() {}
+  virtual void announceSuccess() CXX11_OVERRIDE {}
 
-  virtual void announceFailure() {}
+  virtual void announceFailure() CXX11_OVERRIDE {}
 
-  virtual bool isAllAnnounceFailed() {
+  virtual bool isAllAnnounceFailed() CXX11_OVERRIDE {
     return false;
   }
 
-  virtual void resetAnnounce() {}
+  virtual void resetAnnounce() CXX11_OVERRIDE {}
 
   virtual void processAnnounceResponse(const unsigned char* trackerResponse,
-                                       size_t trackerResponseLength) {}
+                                       size_t trackerResponseLength)
+    CXX11_OVERRIDE
+  {}
 
   virtual void processUDPTrackerResponse
-  (const std::shared_ptr<UDPTrackerRequest>& req) {}
+  (const std::shared_ptr<UDPTrackerRequest>& req) CXX11_OVERRIDE {}
 
-  virtual bool noMoreAnnounce() {
+  virtual bool noMoreAnnounce() CXX11_OVERRIDE {
     return false;
   }
 
-  virtual void shuffleAnnounce() {
+  virtual void shuffleAnnounce() CXX11_OVERRIDE {
   }
 
-  virtual std::string getPeerId() {
-    return peerId;
-  }
+  virtual void overrideMinInterval(time_t interval) CXX11_OVERRIDE {}
 
-  virtual void overrideMinInterval(time_t interval) {}
-
-  virtual void setTcpPort(uint16_t port) {}
+  virtual void setTcpPort(uint16_t port) CXX11_OVERRIDE {}
 
   void setPeerId(const std::string& peerId) {
     this->peerId = peerId;
diff --git a/test/MockBtMessage.h b/test/MockBtMessage.h
index 1de8f223..a07cca59 100644
--- a/test/MockBtMessage.h
+++ b/test/MockBtMessage.h
@@ -50,7 +50,7 @@ public:
 
   virtual ~MockBtMessage() {}
 
-  virtual bool isInvalidate() {
+  virtual bool isInvalidate() CXX11_OVERRIDE {
     return invalidate;
   }
 
@@ -58,7 +58,7 @@ public:
     this->invalidate = flag;
   }
 
-  virtual bool isUploading() {
+  virtual bool isUploading() CXX11_OVERRIDE {
     return uploading;
   }
 
@@ -66,24 +66,25 @@ public:
     this->uploading = flag;
   }
 
-  virtual void doReceivedAction() {
+  virtual void doReceivedAction() CXX11_OVERRIDE {
   }
 
-  virtual void send() {}
+  virtual void send() CXX11_OVERRIDE {}
 
-  virtual void validate() {}
+  virtual void validate() CXX11_OVERRIDE {}
 
   virtual void onAbortOutstandingRequestEvent
-  (const BtAbortOutstandingRequestEvent& event) {}
+  (const BtAbortOutstandingRequestEvent& event) CXX11_OVERRIDE {}
 
   virtual void onCancelSendingPieceEvent
-  (const BtCancelSendingPieceEvent& event) {}
+  (const BtCancelSendingPieceEvent& event) CXX11_OVERRIDE {}
 
-  virtual void onChokingEvent(const BtChokingEvent& event) {}
+  virtual void onChokingEvent(const BtChokingEvent& event) CXX11_OVERRIDE {}
 
-  virtual void onQueued() {}
+  virtual void onQueued() CXX11_OVERRIDE {}
 
-  virtual std::string toString() const { return "MockBtMessage"; }
+  virtual std::string toString() const CXX11_OVERRIDE
+  { return "MockBtMessage"; }
 
 };
 
diff --git a/test/MockBtMessageDispatcher.h b/test/MockBtMessageDispatcher.h
index 7f1aba89..913421f2 100644
--- a/test/MockBtMessageDispatcher.h
+++ b/test/MockBtMessageDispatcher.h
@@ -16,51 +16,63 @@ public:
 
   virtual ~MockBtMessageDispatcher() {}
 
-  virtual void addMessageToQueue(std::unique_ptr<BtMessage> btMessage) {
+  virtual void addMessageToQueue(std::unique_ptr<BtMessage> btMessage)
+    CXX11_OVERRIDE
+  {
     messageQueue.push_back(std::move(btMessage));
   }
 
-  virtual void sendMessages() {}
+  virtual void sendMessages() CXX11_OVERRIDE {}
 
   virtual void doCancelSendingPieceAction
-  (size_t index, int32_t begin, int32_t length) {}
+  (size_t index, int32_t begin, int32_t length) CXX11_OVERRIDE {}
 
-  virtual void doCancelSendingPieceAction(const std::shared_ptr<Piece>& piece) {}
+  virtual void doCancelSendingPieceAction(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE
+  {}
 
-  virtual void doAbortOutstandingRequestAction(const std::shared_ptr<Piece>& piece) {}
+  virtual void doAbortOutstandingRequestAction
+  (const std::shared_ptr<Piece>& piece) CXX11_OVERRIDE {}
 
-  virtual void doChokedAction() {}
+  virtual void doChokedAction() CXX11_OVERRIDE {}
 
-  virtual void doChokingAction() {}
+  virtual void doChokingAction() CXX11_OVERRIDE {}
 
-  virtual void checkRequestSlotAndDoNecessaryThing() {}
+  virtual void checkRequestSlotAndDoNecessaryThing() CXX11_OVERRIDE {}
 
-  virtual bool isSendingInProgress() {
+  virtual bool isSendingInProgress() CXX11_OVERRIDE {
     return false;
   }
 
-  virtual size_t countMessageInQueue() {
+  virtual size_t countMessageInQueue() CXX11_OVERRIDE {
     return messageQueue.size();
   }
 
-  virtual size_t countOutstandingRequest() {
+  virtual size_t countOutstandingRequest() CXX11_OVERRIDE {
     return 0;
   }
 
-  virtual bool isOutstandingRequest(size_t index, size_t blockIndex) {
+  virtual bool isOutstandingRequest(size_t index, size_t blockIndex)
+    CXX11_OVERRIDE
+  {
     return false;
   }
 
   virtual const RequestSlot* getOutstandingRequest
-  (size_t index, int32_t begin, int32_t length) {
+  (size_t index, int32_t begin, int32_t length) CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual void removeOutstandingRequest(const RequestSlot* slot) {}
+  virtual void removeOutstandingRequest(const RequestSlot* slot)
+    CXX11_OVERRIDE
+  {}
 
-  virtual void addOutstandingRequest(std::unique_ptr<RequestSlot> slot) {}
+  virtual void addOutstandingRequest(std::unique_ptr<RequestSlot> slot)
+    CXX11_OVERRIDE
+  {}
 
-  virtual size_t countOutstandingUpload()
+  virtual size_t countOutstandingUpload() CXX11_OVERRIDE
   {
     return 0;
   }
diff --git a/test/MockBtMessageFactory.h b/test/MockBtMessageFactory.h
index 1e0a128a..bf36811d 100644
--- a/test/MockBtMessageFactory.h
+++ b/test/MockBtMessageFactory.h
@@ -33,89 +33,121 @@ public:
   virtual ~MockBtMessageFactory() {}
 
   virtual std::unique_ptr<BtMessage>
-  createBtMessage(const unsigned char* msg, size_t msgLength) {
+  createBtMessage(const unsigned char* msg, size_t msgLength) CXX11_OVERRIDE {
     return nullptr;
   };
 
   virtual std::unique_ptr<BtHandshakeMessage>
-  createHandshakeMessage(const unsigned char* msg, size_t msgLength) {
+  createHandshakeMessage(const unsigned char* msg, size_t msgLength)
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
   virtual std::unique_ptr<BtHandshakeMessage>
   createHandshakeMessage(const unsigned char* infoHash,
-                         const unsigned char* peerId) {
+                         const unsigned char* peerId) CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
   virtual std::unique_ptr<BtRequestMessage>
-  createRequestMessage(const std::shared_ptr<Piece>& piece, size_t blockIndex) {
+  createRequestMessage(const std::shared_ptr<Piece>& piece, size_t blockIndex)
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
   virtual std::unique_ptr<BtCancelMessage>
-  createCancelMessage(size_t index, int32_t begin, int32_t length) {
+  createCancelMessage(size_t index, int32_t begin, int32_t length)
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
   virtual std::unique_ptr<BtPieceMessage>
-  createPieceMessage(size_t index, int32_t begin, int32_t length) {
+  createPieceMessage(size_t index, int32_t begin, int32_t length)
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtHaveMessage> createHaveMessage(size_t index) {
+  virtual std::unique_ptr<BtHaveMessage> createHaveMessage(size_t index)
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtChokeMessage> createChokeMessage() {
+  virtual std::unique_ptr<BtChokeMessage> createChokeMessage()
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtUnchokeMessage> createUnchokeMessage() {
+  virtual std::unique_ptr<BtUnchokeMessage> createUnchokeMessage()
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtInterestedMessage> createInterestedMessage() {
+  virtual std::unique_ptr<BtInterestedMessage> createInterestedMessage()
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtNotInterestedMessage> createNotInterestedMessage() {
+  virtual std::unique_ptr<BtNotInterestedMessage> createNotInterestedMessage()
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtBitfieldMessage> createBitfieldMessage() {
+  virtual std::unique_ptr<BtBitfieldMessage> createBitfieldMessage()
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtKeepAliveMessage> createKeepAliveMessage() {
+  virtual std::unique_ptr<BtKeepAliveMessage> createKeepAliveMessage()
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtHaveAllMessage> createHaveAllMessage() {
+  virtual std::unique_ptr<BtHaveAllMessage> createHaveAllMessage()
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
-  virtual std::unique_ptr<BtHaveNoneMessage> createHaveNoneMessage() {
+  virtual std::unique_ptr<BtHaveNoneMessage> createHaveNoneMessage()
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
   virtual std::unique_ptr<BtRejectMessage>
-  createRejectMessage(size_t index, int32_t begin, int32_t length) {
+  createRejectMessage(size_t index, int32_t begin, int32_t length)
+    CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
   virtual std::unique_ptr<BtAllowedFastMessage> createAllowedFastMessage
-  (size_t index) {
+  (size_t index) CXX11_OVERRIDE
+  {
     return nullptr;
   }
 
   virtual std::unique_ptr<BtPortMessage> createPortMessage(uint16_t port)
+    CXX11_OVERRIDE
   {
     return nullptr;
   }
 
   virtual std::unique_ptr<BtExtendedMessage>
   createBtExtendedMessage(std::unique_ptr<ExtensionMessage> extmsg)
+    CXX11_OVERRIDE
   {
     return nullptr;
   }
diff --git a/test/MockBtProgressInfoFile.h b/test/MockBtProgressInfoFile.h
index fb253e44..00cd7805 100644
--- a/test/MockBtProgressInfoFile.h
+++ b/test/MockBtProgressInfoFile.h
@@ -12,25 +12,25 @@ public:
   MockBtProgressInfoFile() {}
   virtual ~MockBtProgressInfoFile() {}
 
-  virtual std::string getFilename() {
+  virtual std::string getFilename() CXX11_OVERRIDE {
     return filename;
   }
 
-  virtual void setFilename(const std::string& filename) {
+  void setFilename(const std::string& filename) {
     this->filename = filename;
   }
 
-  virtual bool exists() {
+  virtual bool exists() CXX11_OVERRIDE {
     return false;
   }
 
-  virtual void save() {}
+  virtual void save() CXX11_OVERRIDE {}
 
-  virtual void load() {}
+  virtual void load() CXX11_OVERRIDE {}
 
-  virtual void removeFile() {}
+  virtual void removeFile() CXX11_OVERRIDE {}
 
-  virtual void updateFilename() {}
+  virtual void updateFilename() CXX11_OVERRIDE {}
 };
 
 } // namespace aria2
diff --git a/test/MockBtRequestFactory.h b/test/MockBtRequestFactory.h
index 70e9f740..5a1aa938 100644
--- a/test/MockBtRequestFactory.h
+++ b/test/MockBtRequestFactory.h
@@ -10,27 +10,31 @@ class MockBtRequestFactory : public BtRequestFactory {
 public:
   virtual ~MockBtRequestFactory() {}
 
-  virtual void addTargetPiece(const std::shared_ptr<Piece>& piece) {}
+  virtual void addTargetPiece(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE
+  {}
 
-  virtual void removeTargetPiece(const std::shared_ptr<Piece>& piece) {}
+  virtual void removeTargetPiece(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE
+  {}
 
-  virtual void removeAllTargetPiece() {}
+  virtual void removeAllTargetPiece() CXX11_OVERRIDE {}
 
-  virtual size_t countTargetPiece() { return 0; }
+  virtual size_t countTargetPiece() CXX11_OVERRIDE { return 0; }
 
-  virtual size_t countMissingBlock() { return 0; }
+  virtual size_t countMissingBlock() CXX11_OVERRIDE { return 0; }
 
-  virtual void removeCompletedPiece() {}
+  virtual void removeCompletedPiece() CXX11_OVERRIDE {}
 
-  virtual void doChokedAction() {}
+  virtual void doChokedAction() CXX11_OVERRIDE {}
 
   virtual std::vector<std::unique_ptr<BtRequestMessage>> createRequestMessages
-  (size_t max, bool endGame)
+  (size_t max, bool endGame) CXX11_OVERRIDE
   {
     return std::vector<std::unique_ptr<BtRequestMessage>>{};
   }
 
-  virtual std::vector<size_t> getTargetPieceIndexes() const
+  virtual std::vector<size_t> getTargetPieceIndexes() const CXX11_OVERRIDE
   {
     return std::vector<size_t>{};
   }
diff --git a/test/MockDHTMessage.h b/test/MockDHTMessage.h
index 8fb9fd82..ec464572 100644
--- a/test/MockDHTMessage.h
+++ b/test/MockDHTMessage.h
@@ -34,17 +34,19 @@ public:
 
   virtual ~MockDHTMessage() {}
 
-  virtual void doReceivedAction() {}
+  virtual void doReceivedAction() CXX11_OVERRIDE {}
 
-  virtual bool send() { return true; }
+  virtual bool send() CXX11_OVERRIDE { return true; }
 
-  virtual bool isReply() const { return isReply_; }
+  virtual bool isReply() const CXX11_OVERRIDE { return isReply_; }
 
   void setReply(bool f) { isReply_ = f; }
 
-  virtual const std::string& getMessageType() const { return messageType_; }
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE
+  { return messageType_; }
 
-  virtual std::string toString() const { return "MockDHTMessage"; }
+  virtual std::string toString() const CXX11_OVERRIDE
+  { return "MockDHTMessage"; }
 };
 
 class MockDHTQueryMessage:public DHTQueryMessage {
@@ -66,17 +68,20 @@ public:
 
   virtual ~MockDHTQueryMessage() {}
 
-  virtual void doReceivedAction() {}
+  virtual void doReceivedAction() CXX11_OVERRIDE {}
 
-  virtual bool send() { return true; }
+  virtual bool send() CXX11_OVERRIDE { return true; }
 
-  virtual bool isReply() const { return false; }
+  virtual bool isReply() const CXX11_OVERRIDE { return false; }
 
-  virtual const std::string& getMessageType() const { return messageType_; }
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE
+  { return messageType_; }
 
-  virtual std::string toString() const { return "MockDHTMessage"; }
+  virtual std::string toString() const CXX11_OVERRIDE
+  { return "MockDHTMessage"; }
 
-  virtual std::shared_ptr<Dict> getArgument() { return Dict::g(); }
+  virtual std::shared_ptr<Dict> getArgument() CXX11_OVERRIDE
+  { return Dict::g(); }
 };
 
 class MockDHTResponseMessage:public DHTResponseMessage {
@@ -98,19 +103,22 @@ public:
 
   virtual ~MockDHTResponseMessage() {}
 
-  virtual void doReceivedAction() {}
+  virtual void doReceivedAction() CXX11_OVERRIDE {}
 
-  virtual bool send() { return true; }
+  virtual bool send() CXX11_OVERRIDE { return true; }
 
-  virtual bool isReply() const { return true; }
+  virtual bool isReply() const CXX11_OVERRIDE { return true; }
 
-  virtual const std::string& getMessageType() const { return messageType_; }
+  virtual const std::string& getMessageType() const CXX11_OVERRIDE
+  { return messageType_; }
 
-  virtual std::string toString() const { return "MockDHTMessage"; }
+  virtual std::string toString() const CXX11_OVERRIDE
+  { return "MockDHTMessage"; }
 
-  virtual std::shared_ptr<Dict> getResponse() { return Dict::g(); }
+  virtual std::shared_ptr<Dict> getResponse() CXX11_OVERRIDE
+  { return Dict::g(); }
 
-  virtual void accept(DHTMessageCallback* callback) {}
+  virtual void accept(DHTMessageCallback* callback) CXX11_OVERRIDE {}
 };
 
 } // namespace aria2
diff --git a/test/MockDHTMessageCallback.h b/test/MockDHTMessageCallback.h
index ed574771..a579ebef 100644
--- a/test/MockDHTMessageCallback.h
+++ b/test/MockDHTMessageCallback.h
@@ -11,15 +11,18 @@ public:
 
   virtual ~MockDHTMessageCallback() {}
 
-  virtual void visit(const DHTAnnouncePeerReplyMessage* message) {}
+  virtual void visit(const DHTAnnouncePeerReplyMessage* message) CXX11_OVERRIDE
+  {}
 
-  virtual void visit(const DHTFindNodeReplyMessage* message) {}
+  virtual void visit(const DHTFindNodeReplyMessage* message) CXX11_OVERRIDE {}
 
-  virtual void visit(const DHTGetPeersReplyMessage* message) {}
+  virtual void visit(const DHTGetPeersReplyMessage* message) CXX11_OVERRIDE {}
 
-  virtual void visit(const DHTPingReplyMessage* message) {}
+  virtual void visit(const DHTPingReplyMessage* message) CXX11_OVERRIDE {}
 
-  virtual void onTimeout(const std::shared_ptr<DHTNode>& remoteNode) {}
+  virtual void onTimeout(const std::shared_ptr<DHTNode>& remoteNode)
+    CXX11_OVERRIDE
+  {}
 };
 
 } // namespace aria2
diff --git a/test/MockDHTMessageDispatcher.h b/test/MockDHTMessageDispatcher.h
index 60388b82..6c9dd42a 100644
--- a/test/MockDHTMessageDispatcher.h
+++ b/test/MockDHTMessageDispatcher.h
@@ -32,7 +32,7 @@ public:
   addMessageToQueue(std::unique_ptr<DHTMessage> message,
                     time_t timeout,
                     std::unique_ptr<DHTMessageCallback> callback =
-                    std::unique_ptr<DHTMessageCallback>{})
+                    std::unique_ptr<DHTMessageCallback>{}) CXX11_OVERRIDE
   {
     messageQueue_.push_back(Entry(std::move(message), timeout,
                                   std::move(callback)));
@@ -41,15 +41,15 @@ public:
   virtual void
   addMessageToQueue(std::unique_ptr<DHTMessage> message,
                     std::unique_ptr<DHTMessageCallback> callback =
-                    std::unique_ptr<DHTMessageCallback>{})
+                    std::unique_ptr<DHTMessageCallback>{}) CXX11_OVERRIDE
   {
     messageQueue_.push_back(Entry(std::move(message), DHT_MESSAGE_TIMEOUT,
                                   std::move(callback)));
   }
 
-  virtual void sendMessages() {}
+  virtual void sendMessages() CXX11_OVERRIDE {}
 
-  virtual size_t countMessageInQueue() const
+  virtual size_t countMessageInQueue() const CXX11_OVERRIDE
   {
     return messageQueue_.size();
   }
diff --git a/test/MockDHTMessageFactory.h b/test/MockDHTMessageFactory.h
index 96914b53..458e9a9d 100644
--- a/test/MockDHTMessageFactory.h
+++ b/test/MockDHTMessageFactory.h
@@ -24,7 +24,7 @@ public:
 
   virtual std::unique_ptr<DHTQueryMessage>
   createQueryMessage(const Dict* dict,
-                     const std::string& ipaddr, uint16_t port)
+                     const std::string& ipaddr, uint16_t port) CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -33,6 +33,7 @@ public:
   createResponseMessage(const std::string& messageType,
                         const Dict* dict,
                         const std::string& ipaddr, uint16_t port)
+    CXX11_OVERRIDE
   {
     auto remoteNode = std::make_shared<DHTNode>();
     // TODO At this point, removeNode's ID is random.
@@ -44,7 +45,7 @@ public:
 
   virtual std::unique_ptr<DHTPingMessage>
   createPingMessage(const std::shared_ptr<DHTNode>& remoteNode,
-                    const std::string& transactionID = "")
+                    const std::string& transactionID = "") CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -52,7 +53,7 @@ public:
   virtual std::unique_ptr<DHTPingReplyMessage>
   createPingReplyMessage(const std::shared_ptr<DHTNode>& remoteNode,
                          const unsigned char* remoteNodeID,
-                         const std::string& transactionID)
+                         const std::string& transactionID) CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -60,7 +61,7 @@ public:
   virtual std::unique_ptr<DHTFindNodeMessage>
   createFindNodeMessage(const std::shared_ptr<DHTNode>& remoteNode,
                         const unsigned char* targetNodeID,
-                        const std::string& transactionID = "")
+                        const std::string& transactionID = "") CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -69,7 +70,7 @@ public:
   createFindNodeReplyMessage
   (const std::shared_ptr<DHTNode>& remoteNode,
    std::vector<std::shared_ptr<DHTNode>> closestKNodes,
-   const std::string& transactionID)
+   const std::string& transactionID) CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -77,7 +78,7 @@ public:
   virtual std::unique_ptr<DHTGetPeersMessage>
   createGetPeersMessage(const std::shared_ptr<DHTNode>& remoteNode,
                         const unsigned char* infoHash,
-                        const std::string& transactionID)
+                        const std::string& transactionID) CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -88,7 +89,7 @@ public:
    std::vector<std::shared_ptr<DHTNode>> closestKNodes,
    std::vector<std::shared_ptr<Peer>> peers,
    const std::string& token,
-   const std::string& transactionID)
+   const std::string& transactionID) CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -99,6 +100,7 @@ public:
                             uint16_t tcpPort,
                             const std::string& token,
                             const std::string& transactionID = "")
+    CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -106,13 +108,14 @@ public:
   virtual std::unique_ptr<DHTAnnouncePeerReplyMessage>
   createAnnouncePeerReplyMessage(const std::shared_ptr<DHTNode>& remoteNode,
                                  const std::string& transactionID)
+    CXX11_OVERRIDE
   {
     return nullptr;
   }
 
   virtual std::unique_ptr<DHTUnknownMessage>
   createUnknownMessage(const unsigned char* data, size_t length,
-                       const std::string& ipaddr, uint16_t port)
+                       const std::string& ipaddr, uint16_t port) CXX11_OVERRIDE
   {
     return nullptr;
   }
diff --git a/test/MockDHTTask.h b/test/MockDHTTask.h
index 8823a631..284f7098 100644
--- a/test/MockDHTTask.h
+++ b/test/MockDHTTask.h
@@ -24,9 +24,9 @@ public:
 
   virtual ~MockDHTTask() {}
 
-  virtual void startup() {}
+  virtual void startup() CXX11_OVERRIDE {}
 
-  virtual bool finished()
+  virtual bool finished() CXX11_OVERRIDE
   {
     return finished_;
   }
diff --git a/test/MockDHTTaskFactory.h b/test/MockDHTTaskFactory.h
index b93465a0..c1a312d0 100644
--- a/test/MockDHTTaskFactory.h
+++ b/test/MockDHTTaskFactory.h
@@ -11,18 +11,18 @@ public:
 
   virtual std::shared_ptr<DHTTask>
   createPingTask(const std::shared_ptr<DHTNode>& remoteNode,
-                 int numRetry = 0)
+                 int numRetry = 0) CXX11_OVERRIDE
   {
     return nullptr;
   }
 
   virtual std::shared_ptr<DHTTask>
-  createNodeLookupTask(const unsigned char* targetID)
+  createNodeLookupTask(const unsigned char* targetID) CXX11_OVERRIDE
   {
     return nullptr;
   }
 
-  virtual std::shared_ptr<DHTTask> createBucketRefreshTask()
+  virtual std::shared_ptr<DHTTask> createBucketRefreshTask() CXX11_OVERRIDE
   {
     return nullptr;
   }
@@ -31,19 +31,20 @@ public:
   createPeerLookupTask(const std::shared_ptr<DownloadContext>& ctx,
                        uint16_t tcpPort,
                        const std::shared_ptr<PeerStorage>& peerStorage)
+    CXX11_OVERRIDE
   {
     return nullptr;
   }
 
   virtual std::shared_ptr<DHTTask>
-  createPeerAnnounceTask(const unsigned char* infoHash)
+  createPeerAnnounceTask(const unsigned char* infoHash) CXX11_OVERRIDE
   {
     return nullptr;
   }
 
   virtual std::shared_ptr<DHTTask>
   createReplaceNodeTask(const std::shared_ptr<DHTBucket>& bucket,
-                        const std::shared_ptr<DHTNode>& newNode)
+                        const std::shared_ptr<DHTNode>& newNode) CXX11_OVERRIDE
   {
     return nullptr;
   }
diff --git a/test/MockDHTTaskQueue.h b/test/MockDHTTaskQueue.h
index 62ea3714..e4434be6 100644
--- a/test/MockDHTTaskQueue.h
+++ b/test/MockDHTTaskQueue.h
@@ -17,19 +17,22 @@ public:
 
   virtual ~MockDHTTaskQueue() {}
 
-  virtual void executeTask() {}
+  virtual void executeTask() CXX11_OVERRIDE {}
 
   virtual void addPeriodicTask1(const std::shared_ptr<DHTTask>& task)
+    CXX11_OVERRIDE
   {
     periodicTaskQueue1_.push_back(task);
   }
 
   virtual void addPeriodicTask2(const std::shared_ptr<DHTTask>& task)
+    CXX11_OVERRIDE
   {
     periodicTaskQueue2_.push_back(task);
   }
 
   virtual void addImmediateTask(const std::shared_ptr<DHTTask>& task)
+    CXX11_OVERRIDE
   {
     immediateTaskQueue_.push_back(task);
   }
diff --git a/test/MockExtensionMessage.h b/test/MockExtensionMessage.h
index 06861e34..7a4f07e4 100644
--- a/test/MockExtensionMessage.h
+++ b/test/MockExtensionMessage.h
@@ -39,27 +39,27 @@ public:
       evcheck_{evcheck}
   {}
 
-  virtual std::string getPayload()
+  virtual std::string getPayload() CXX11_OVERRIDE
   {
     return data_;
   }
 
-  virtual uint8_t getExtensionMessageID() const
+  virtual uint8_t getExtensionMessageID() const CXX11_OVERRIDE
   {
     return extensionMessageID_;
   }
 
-  virtual const char* getExtensionName() const
+  virtual const char* getExtensionName() const CXX11_OVERRIDE
   {
     return extensionName_.c_str();
   }
 
-  virtual std::string toString() const
+  virtual std::string toString() const CXX11_OVERRIDE
   {
     return extensionName_;
   }
 
-  virtual void doReceivedAction()
+  virtual void doReceivedAction() CXX11_OVERRIDE
   {
     if(evcheck_) {
       evcheck_->doReceivedActionCalled = true;
diff --git a/test/MockExtensionMessageFactory.h b/test/MockExtensionMessageFactory.h
index ec138cb3..75e77a46 100644
--- a/test/MockExtensionMessageFactory.h
+++ b/test/MockExtensionMessageFactory.h
@@ -11,7 +11,7 @@ public:
   virtual ~MockExtensionMessageFactory() {}
 
   virtual std::unique_ptr<ExtensionMessage>
-  createMessage(const unsigned char* data, size_t length)
+  createMessage(const unsigned char* data, size_t length) CXX11_OVERRIDE
   {
     return make_unique<MockExtensionMessage>
       ("a2_mock", *data, data+1, length-1, nullptr);
diff --git a/test/MockPeerStorage.h b/test/MockPeerStorage.h
index 2b8176ff..79518afa 100644
--- a/test/MockPeerStorage.h
+++ b/test/MockPeerStorage.h
@@ -20,13 +20,15 @@ public:
   MockPeerStorage():numChokeExecuted_(0) {}
   virtual ~MockPeerStorage() {}
 
-  virtual bool addPeer(const std::shared_ptr<Peer>& peer)
+  virtual bool addPeer(const std::shared_ptr<Peer>& peer) CXX11_OVERRIDE
   {
     unusedPeers.push_back(peer);
     return true;
   }
 
-  virtual void addPeer(const std::vector<std::shared_ptr<Peer> >& peers) {
+  virtual void addPeer(const std::vector<std::shared_ptr<Peer> >& peers)
+    CXX11_OVERRIDE
+  {
     unusedPeers.insert(unusedPeers.end(), peers.begin(), peers.end());
   }
 
@@ -35,12 +37,14 @@ public:
     return unusedPeers;
   }
 
-  virtual size_t countAllPeer() const
+  virtual size_t countAllPeer() const CXX11_OVERRIDE
   {
     return unusedPeers.size() + usedPeers.size();
   }
 
-  virtual const std::deque<std::shared_ptr<Peer> >& getDroppedPeers() {
+  virtual const std::deque<std::shared_ptr<Peer> >& getDroppedPeers()
+    CXX11_OVERRIDE
+  {
     return droppedPeers;
   }
 
@@ -48,7 +52,8 @@ public:
     droppedPeers.push_back(peer);
   }
 
-  virtual bool isPeerAvailable() {
+  virtual bool isPeerAvailable() CXX11_OVERRIDE
+  {
     return false;
   }
 
@@ -61,35 +66,35 @@ public:
     peers.insert(peers.end(), activePeers.begin(), activePeers.end());
   }
 
-  virtual const PeerSet& getUsedPeers()
+  virtual const PeerSet& getUsedPeers() CXX11_OVERRIDE
   {
     return usedPeers;
   }
 
-  virtual bool isBadPeer(const std::string& ipaddr)
+  virtual bool isBadPeer(const std::string& ipaddr) CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual void addBadPeer(const std::string& ipaddr)
+  virtual void addBadPeer(const std::string& ipaddr) CXX11_OVERRIDE
   {
   }
 
-  virtual std::shared_ptr<Peer> checkoutPeer(cuid_t cuid)
+  virtual std::shared_ptr<Peer> checkoutPeer(cuid_t cuid) CXX11_OVERRIDE
   {
     return nullptr;
   }
 
-  virtual void returnPeer(const std::shared_ptr<Peer>& peer)
+  virtual void returnPeer(const std::shared_ptr<Peer>& peer) CXX11_OVERRIDE
   {
   }
 
-  virtual bool chokeRoundIntervalElapsed()
+  virtual bool chokeRoundIntervalElapsed() CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual void executeChoke()
+  virtual void executeChoke() CXX11_OVERRIDE
   {
     ++numChokeExecuted_;
   }
diff --git a/test/MockPieceSelector.h b/test/MockPieceSelector.h
index 7723c97a..af55076e 100644
--- a/test/MockPieceSelector.h
+++ b/test/MockPieceSelector.h
@@ -9,6 +9,7 @@ class MockPieceSelector:public PieceSelector {
 public:
   virtual bool select
   (size_t& index, const unsigned char* bitfield, size_t nbits) const
+    CXX11_OVERRIDE
   {
     return false;
   }
diff --git a/test/MockPieceStorage.h b/test/MockPieceStorage.h
index dc39594b..4886d9c5 100644
--- a/test/MockPieceStorage.h
+++ b/test/MockPieceStorage.h
@@ -40,7 +40,9 @@ public:
 
 #ifdef ENABLE_BITTORRENT
 
-  virtual bool hasMissingPiece(const std::shared_ptr<Peer>& peer) {
+  virtual bool hasMissingPiece(const std::shared_ptr<Peer>& peer)
+    CXX11_OVERRIDE
+  {
     return false;
   }
 
@@ -48,7 +50,7 @@ public:
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
-   cuid_t cuid)
+   cuid_t cuid) CXX11_OVERRIDE
   {}
 
   virtual void getMissingPiece
@@ -56,14 +58,14 @@ public:
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid)
+   cuid_t cuid) CXX11_OVERRIDE
   {}
 
   virtual void getMissingFastPiece
   (std::vector<std::shared_ptr<Piece> >& pieces,
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
-   cuid_t cuid)
+   cuid_t cuid) CXX11_OVERRIDE
   {}
 
   virtual void getMissingFastPiece
@@ -71,12 +73,12 @@ public:
    size_t minMissingBlocks,
    const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid)
+   cuid_t cuid) CXX11_OVERRIDE
   {}
 
   virtual std::shared_ptr<Piece> getMissingPiece
   (const std::shared_ptr<Peer>& peer,
-   cuid_t cuid)
+   cuid_t cuid) CXX11_OVERRIDE
   {
     return std::shared_ptr<Piece>(new Piece());
   }
@@ -84,14 +86,14 @@ public:
   virtual std::shared_ptr<Piece> getMissingPiece
   (const std::shared_ptr<Peer>& peer,
    const std::vector<size_t>& excludedIndexes,
-   cuid_t cuid)
+   cuid_t cuid) CXX11_OVERRIDE
   {
     return std::shared_ptr<Piece>(new Piece());
   }
 
 #endif // ENABLE_BITTORRENT
 
-  virtual bool hasMissingUnusedPiece()
+  virtual bool hasMissingUnusedPiece() CXX11_OVERRIDE
   {
     return false;
   }
@@ -100,38 +102,46 @@ public:
   (size_t minSplitSize,
    const unsigned char* ignoreBitfield,
    size_t length,
-   cuid_t cuid)
+   cuid_t cuid) CXX11_OVERRIDE
   {
     return std::shared_ptr<Piece>(new Piece());
   }
 
   virtual std::shared_ptr<Piece> getMissingPiece(size_t index, cuid_t cuid)
+    CXX11_OVERRIDE
   {
     return std::shared_ptr<Piece>(new Piece());
   }
 
-  virtual bool isPieceUsed(size_t index)
+  virtual bool isPieceUsed(size_t index) CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual void markPieceMissing(size_t index) {}
+  virtual void markPieceMissing(size_t index) CXX11_OVERRIDE {}
 
-  virtual void markPiecesDone(int64_t) {}
+  virtual void markPiecesDone(int64_t) CXX11_OVERRIDE {}
 
-  virtual std::shared_ptr<Piece> getPiece(size_t index) {
+  virtual std::shared_ptr<Piece> getPiece(size_t index) CXX11_OVERRIDE
+  {
     return std::shared_ptr<Piece>(new Piece());
   }
 
-  virtual void completePiece(const std::shared_ptr<Piece>& piece) {}
+  virtual void completePiece(const std::shared_ptr<Piece>& piece)
+    CXX11_OVERRIDE
+  {}
 
-  virtual void cancelPiece(const std::shared_ptr<Piece>& piece, cuid_t cuid) {}
+  virtual void cancelPiece(const std::shared_ptr<Piece>& piece, cuid_t cuid)
+    CXX11_OVERRIDE
+  {}
 
-  virtual bool hasPiece(size_t index) {
+  virtual bool hasPiece(size_t index) CXX11_OVERRIDE
+  {
     return false;
   }
 
-  virtual int64_t getTotalLength() {
+  virtual int64_t getTotalLength() CXX11_OVERRIDE
+  {
     return totalLength;
   }
 
@@ -139,7 +149,8 @@ public:
     this->totalLength = totalLength;
   }
 
-  virtual int64_t getFilteredTotalLength() {
+  virtual int64_t getFilteredTotalLength() CXX11_OVERRIDE
+  {
     return filteredTotalLength;
   }
 
@@ -147,7 +158,8 @@ public:
     this->filteredTotalLength = totalLength;
   }
 
-  virtual int64_t getCompletedLength() {
+  virtual int64_t getCompletedLength() CXX11_OVERRIDE
+  {
     return completedLength;
   }
 
@@ -155,7 +167,8 @@ public:
     this->completedLength = completedLength;
   }
 
-  virtual int64_t getFilteredCompletedLength() {
+  virtual int64_t getFilteredCompletedLength() CXX11_OVERRIDE
+  {
     return filteredCompletedLength;
   }
 
@@ -163,11 +176,12 @@ public:
     this->filteredCompletedLength = completedLength;
   }
 
-  virtual void setupFileFilter() {}
+  virtual void setupFileFilter() CXX11_OVERRIDE {}
 
-  virtual void clearFileFilter() {}
+  virtual void clearFileFilter() CXX11_OVERRIDE {}
 
-  virtual bool downloadFinished() {
+  virtual bool downloadFinished() CXX11_OVERRIDE
+  {
     return downloadFinished_;
   }
 
@@ -176,7 +190,8 @@ public:
     downloadFinished_ = f;
   }
 
-  virtual bool allDownloadFinished() {
+  virtual bool allDownloadFinished() CXX11_OVERRIDE
+  {
     return allDownloadFinished_;
   }
 
@@ -185,18 +200,21 @@ public:
     allDownloadFinished_ = f;
   }
 
-  virtual void initStorage() {}
+  virtual void initStorage() CXX11_OVERRIDE {}
 
-  virtual const unsigned char* getBitfield() {
+  virtual const unsigned char* getBitfield() CXX11_OVERRIDE
+  {
     return bitfieldMan->getBitfield();
   }
 
   virtual void setBitfield(const unsigned char* bitfield,
-                           size_t bitfieldLength) {
+                           size_t bitfieldLength) CXX11_OVERRIDE
+  {
     bitfieldMan->setBitfield(bitfield, bitfieldLength);
   }
 
-  virtual size_t getBitfieldLength() {
+  virtual size_t getBitfieldLength() CXX11_OVERRIDE
+  {
     return bitfieldMan->getBitfieldLength();
   }
 
@@ -204,7 +222,8 @@ public:
     this->bitfieldMan = bitfieldMan;
   }
 
-  virtual bool isSelectiveDownloadingMode() {
+  virtual bool isSelectiveDownloadingMode() CXX11_OVERRIDE
+  {
     return selectiveDownloadingMode;
   }
 
@@ -212,31 +231,36 @@ public:
     this->selectiveDownloadingMode = flag;
   }
 
-  virtual bool isEndGame() {
+  virtual bool isEndGame() CXX11_OVERRIDE
+  {
     return endGame;
   }
 
-  virtual void setEndGamePieceNum(size_t num) {}
+  virtual void setEndGamePieceNum(size_t num) CXX11_OVERRIDE {}
 
-  virtual void enterEndGame() {
+  virtual void enterEndGame() CXX11_OVERRIDE
+  {
     this->endGame = true;
   }
 
-  virtual std::shared_ptr<DiskAdaptor> getDiskAdaptor() {
+  virtual std::shared_ptr<DiskAdaptor> getDiskAdaptor() CXX11_OVERRIDE
+  {
     return diskAdaptor;
   }
 
-  virtual WrDiskCache* getWrDiskCache() {
+  virtual WrDiskCache* getWrDiskCache() CXX11_OVERRIDE
+  {
     return 0;
   }
 
-  virtual void flushWrDiskCacheEntry() {}
+  virtual void flushWrDiskCacheEntry() CXX11_OVERRIDE {}
 
   void setDiskAdaptor(const std::shared_ptr<DiskAdaptor>& adaptor) {
     this->diskAdaptor = adaptor;
   }
 
-  virtual int32_t getPieceLength(size_t index) {
+  virtual int32_t getPieceLength(size_t index) CXX11_OVERRIDE
+  {
     return pieceLengthList.at(index);
   }
 
@@ -244,50 +268,55 @@ public:
     pieceLengthList.push_back(length);
   }
 
-  virtual void advertisePiece(cuid_t cuid, size_t index) {}
+  virtual void advertisePiece(cuid_t cuid, size_t index) CXX11_OVERRIDE {}
 
   virtual void getAdvertisedPieceIndexes(std::vector<size_t>& indexes,
                                          cuid_t myCuid,
                                          const Timer& lastCheckTime)
+    CXX11_OVERRIDE
   {}
 
-  virtual void removeAdvertisedPiece(time_t elapsed) {}
+  virtual void removeAdvertisedPiece(time_t elapsed) CXX11_OVERRIDE {}
 
-  virtual void markAllPiecesDone() {}
+  virtual void markAllPiecesDone() CXX11_OVERRIDE {}
 
-  virtual void addInFlightPiece(const std::vector<std::shared_ptr<Piece> >& pieces)
+  virtual void addInFlightPiece
+  (const std::vector<std::shared_ptr<Piece> >& pieces) CXX11_OVERRIDE
   {
     std::copy(pieces.begin(), pieces.end(), back_inserter(inFlightPieces));
   }
 
-  virtual size_t countInFlightPiece()
+  virtual size_t countInFlightPiece() CXX11_OVERRIDE
   {
     return inFlightPieces.size();
   }
 
   virtual void getInFlightPieces(std::vector<std::shared_ptr<Piece> >& pieces)
+    CXX11_OVERRIDE
   {
     pieces.insert(pieces.end(), inFlightPieces.begin(), inFlightPieces.end());
   }
 
-  virtual void addPieceStats(size_t index) {}
+  virtual void addPieceStats(size_t index) CXX11_OVERRIDE {}
 
   virtual void addPieceStats(const unsigned char* bitfield,
-                             size_t bitfieldLength) {}
+                             size_t bitfieldLength) CXX11_OVERRIDE {}
 
   virtual void subtractPieceStats(const unsigned char* bitfield,
-                                  size_t bitfieldLength) {}
+                                  size_t bitfieldLength) CXX11_OVERRIDE {}
 
   virtual void updatePieceStats(const unsigned char* newBitfield,
                                 size_t newBitfieldLength,
-                                const unsigned char* oldBitfield) {}
+                                const unsigned char* oldBitfield)
+    CXX11_OVERRIDE
+  {}
 
-  virtual size_t getNextUsedIndex(size_t index)
+  virtual size_t getNextUsedIndex(size_t index) CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual void onDownloadIncomplete() {}
+  virtual void onDownloadIncomplete() CXX11_OVERRIDE {}
 };
 
 } // namespace aria2
diff --git a/test/MockSegment.h b/test/MockSegment.h
index 4cdebbdf..b25a8dc9 100644
--- a/test/MockSegment.h
+++ b/test/MockSegment.h
@@ -9,67 +9,67 @@ namespace aria2 {
 
 class MockSegment:public Segment {
 public:
-  virtual bool complete() const
+  virtual bool complete() const CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual size_t getIndex() const
+  virtual size_t getIndex() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int64_t getPosition() const
+  virtual int64_t getPosition() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int64_t getPositionToWrite() const
+  virtual int64_t getPositionToWrite() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int32_t getLength() const
+  virtual int32_t getLength() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int32_t getSegmentLength() const
+  virtual int32_t getSegmentLength() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual int32_t getWrittenLength() const
+  virtual int32_t getWrittenLength() const CXX11_OVERRIDE
   {
     return 0;
   }
 
-  virtual void updateWrittenLength(int32_t bytes) {}
+  virtual void updateWrittenLength(int32_t bytes) CXX11_OVERRIDE {}
 
 #ifdef ENABLE_MESSAGE_DIGEST
 
   // `begin' is a offset inside this segment.
   virtual bool updateHash
-  (int32_t begin, const unsigned char* data, size_t dataLength)
+  (int32_t begin, const unsigned char* data, size_t dataLength) CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual bool isHashCalculated() const
+  virtual bool isHashCalculated() const CXX11_OVERRIDE
   {
     return false;
   }
 
-  virtual std::string getDigest()
+  virtual std::string getDigest() CXX11_OVERRIDE
   {
     return A2STR::NIL;
   }
 
 #endif // ENABLE_MESSAGE_DIGEST
 
-  virtual void clear(WrDiskCache* diskCache) {}
+  virtual void clear(WrDiskCache* diskCache) CXX11_OVERRIDE {}
 
-  virtual std::shared_ptr<Piece> getPiece() const
+  virtual std::shared_ptr<Piece> getPiece() const CXX11_OVERRIDE
   {
     return std::shared_ptr<Piece>(new Piece());
   }
diff --git a/test/SinkStreamFilterTest.cc b/test/SinkStreamFilterTest.cc
index c2d0adb4..e711a534 100644
--- a/test/SinkStreamFilterTest.cc
+++ b/test/SinkStreamFilterTest.cc
@@ -22,17 +22,17 @@ class SinkStreamFilterTest:public CppUnit::TestFixture {
   public:
     MockSegment2(int32_t length):length(length), writtenLength(0) {}
 
-    virtual int32_t getLength() const
+    virtual int32_t getLength() const CXX11_OVERRIDE
     {
       return length;
     }
 
-    virtual int32_t getWrittenLength() const
+    virtual int32_t getWrittenLength() const CXX11_OVERRIDE
     {
       return writtenLength;
     }
 
-    virtual void updateWrittenLength(int32_t bytes)
+    virtual void updateWrittenLength(int32_t bytes) CXX11_OVERRIDE
     {
       writtenLength += bytes;
     }
diff --git a/test/UTMetadataRequestFactoryTest.cc b/test/UTMetadataRequestFactoryTest.cc
index caa6f080..eb15163f 100644
--- a/test/UTMetadataRequestFactoryTest.cc
+++ b/test/UTMetadataRequestFactoryTest.cc
@@ -31,7 +31,7 @@ public:
     virtual std::shared_ptr<Piece> getMissingPiece
     (const std::shared_ptr<Peer>& peer,
      const std::vector<size_t>& exlucdedIndexes,
-     cuid_t cuid)
+     cuid_t cuid) CXX11_OVERRIDE
     {
       if(missingIndexes.empty()) {
         return nullptr;