diff --git a/src/util/in-memory-storage-fifo.hpp b/src/util/in-memory-storage-fifo.hpp
index 4d522a4..3710284 100644
--- a/src/util/in-memory-storage-fifo.hpp
+++ b/src/util/in-memory-storage-fifo.hpp
@@ -43,26 +43,23 @@
   explicit
   InMemoryStorageFifo(boost::asio::io_service& ioService, size_t limit = 10);
 
-  virtual
-  ~InMemoryStorageFifo();
-
 NDN_CXX_PUBLIC_WITH_TESTS_ELSE_PROTECTED:
   /** @brief Removes one Data packet from in-memory storage based on FIFO
    *  @return{ whether the Data was removed }
    */
   virtual bool
-  evictItem();
+  evictItem() override;
 
   /** @brief Update the entry after a entry is successfully inserted, add it to the cleanupIndex
    */
   virtual void
-  afterInsert(InMemoryStorageEntry* entry);
+  afterInsert(InMemoryStorageEntry* entry) override;
 
   /** @brief Update the entry or other data structures before a entry is successfully erased,
    *  erase it from the cleanupIndex
    */
   virtual void
-  beforeErase(InMemoryStorageEntry* entry);
+  beforeErase(InMemoryStorageEntry* entry) override;
 
 private:
   //multi_index_container to implement FIFO