diff --git a/include/libtorrent/create_torrent.hpp b/include/libtorrent/create_torrent.hpp
index ff52a83eb..b0fb9c94b 100644
--- a/include/libtorrent/create_torrent.hpp
+++ b/include/libtorrent/create_torrent.hpp
@@ -391,7 +391,7 @@ namespace detail {
 	// object. The optional function ``f`` is called in between every hash that is set. ``f``
 	// must have the following signature::
 	//
-	// 	void Fun(int);
+	// 	void Fun(piece_index_t);
 	//
 	// The overloads that don't take an ``error_code&`` may throw an exception in case of a
 	// file error, the other overloads sets the error code to reflect the error, if any.
@@ -408,8 +408,8 @@ namespace detail {
 		set_piece_hashes(t, p, detail::nop, ec);
 		if (ec) throw system_error(ec);
 	}
-	template <class Fun>
-	void set_piece_hashes(create_torrent& t, std::string const& p, Fun f)
+	inline void set_piece_hashes(create_torrent& t, std::string const& p
+		, std::function<void(piece_index_t)> const& f)
 	{
 		error_code ec;
 		set_piece_hashes(t, p, f, ec);
@@ -439,9 +439,9 @@ namespace detail {
 		, std::function<void(int)> f, error_code& ec);
 
 #ifndef BOOST_NO_EXCEPTIONS
-	template <class Fun>
 	TORRENT_DEPRECATED
-	void set_piece_hashes(create_torrent& t, std::wstring const& p, Fun f)
+	inline void set_piece_hashes(create_torrent& t, std::wstring const& p
+		, std::function<void(int)> f)
 	{
 		error_code ec;
 		set_piece_hashes_deprecated(t, p, f, ec);