anchor.diff:  stop() ->
       ?NOT_LOADED.
       
  +%% @doc Set the callback process id.
   set_pid(_) ->
       ?NOT_LOADED.
   
  +%% @doc Load a track into the player for playback. `ok' will be
  +%% returned when the track was loaded immediately into the
  +%% player. When the track did not came from the cache, the atom
  +%% `loading' is returned, in this case you need to wait for the
  +%% message <pre>{'$spotify_callback', player_load, loaded}</pre>
  +%% before attempting to play the track.
  +-spec player_load(string()) -> loading | ok.
   player_load(_Track) ->
       ?NOT_LOADED.
   
   player_prefetch(_Track) ->
       ?NOT_LOADED.
   
  +%% @doc Toggle the play state of the currently loaded track.
  +-spec player_play(boolean()) -> ok | {error, term()}.
   player_play(_Play) ->
       ?NOT_LOADED.
   
  +%% @doc Seek to position in the currently loaded track. The track offset is given in milliseconds.
  +-spec player_seek(Offset::non_neg_integer()) -> ok | {error, term()}.
   player_seek(_Offset) ->
       ?NOT_LOADED.
   
  +%% @doc Stops the currently playing track.
  +-spec player_unload() -> ok | {error, term()}.
   player_unload() ->
       ?NOT_LOADED.
  
positive.code:              end,
      ok = erlang:load_nif(SoName, 0).
  
  %% @doc Start the NIF spotify main loop. Only one spotify session per
  %% VM is supported; this is a limitation of libspotify. The pid given
  %% will receive callback messages.
  -spec start(string(), string(), pid()) -> ok | {error, already_started}.
  start(_, _, _) ->
      ?NOT_LOADED.
  
negative.code: %% @doc The libspotify Erlang Interface. 
  %%
  %% <h3>Callback messages</h3> Many calls will at some point in time an
  %% asynchronous callback message. For this purpose, the start/3
  %% function has a pid() argument, and a set_pid/1 function is provided
  %% to later change the callback pid.
  %%
  %% Callback messages are tagged tuples of the form
  %% <pre>{'$spotify_callback', CallbackName::atom(), term()}</pre>,
  %% where CallbackName is an atom named after the C function that
  %% triggered the message; and term is a result term.
  %%
  %% @author Arjan Scherpenisse
  -module(espotify_nif).
  
  -export([
  