In common.h, define func_lib for function objects.  In configure.ac, define HAVE_STD_FUNCTION and HAVE_BOOST_FUNCTION.  Include function headers in ndnboost.
diff --git a/libs/functional/hash/examples/books.cpp b/libs/functional/hash/examples/books.cpp
new file mode 100644
index 0000000..8802e0e
--- /dev/null
+++ b/libs/functional/hash/examples/books.cpp
@@ -0,0 +1,51 @@
+
+// Copyright 2005-2009 Daniel James.
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#include "./books.hpp"
+#include <boost/functional/hash.hpp>
+#include <cassert>
+
+// If std::unordered_set was available:
+//#include <unordered_set>
+
+// This example illustrates how to use ndnboost::hash with a custom hash function.
+// For full details, see the tutorial.
+
+int main()
+{
+    library::book knife(3458, "Zane Grey", "The Hash Knife Outfit");
+    library::book dandelion(1354, "Paul J. Shanley", "Hash & Dandelion Greens");
+
+    ndnboost::hash<library::book> book_hasher;
+    std::size_t knife_hash_value = book_hasher(knife);
+    (void)knife_hash_value; // suppress unused variable warning
+
+    // If std::unordered_set was available:
+    //
+    //std::unordered_set<library::book, ndnboost::hash<library::book> > books;
+    //books.insert(knife);
+    //books.insert(library::book(2443, "Lindgren, Torgny", "Hash"));
+    //books.insert(library::book(1953, "Snyder, Bernadette M.",
+    //    "Heavenly Hash: A Tasty Mix of a Mother's Meditations"));
+
+    //assert(books.find(knife) != books.end());
+    //assert(books.find(dandelion) == books.end());
+
+    return 0;
+}
+
+namespace library
+{
+    bool operator==(book const& a, book const& b)
+    {
+        return a.id == b.id;
+    }
+
+    std::size_t hash_value(book const& b)
+    {
+        ndnboost::hash<int> hasher;
+        return hasher(b.id);
+    }
+}