Differences between modules and library modules.

[Enrique Marcote Peña]

What are the differences between a module and a "library module"? And 
what about internal exports and external exports, are they different for 
the compiler indeed?

The library module skeleton created by the erlang mode looks like this:

%%%-------------------------------------------------------------------
%%% File : my_math.erl
%%% Author : Enrique Marcote Pe?a <mpquique@REDACTED>
%%% Description : Mathematical functions not included on math
%%%
%%% Created : 11 Feb 2003 by Enrique Marcote Pe?a <mpquique@REDACTED>
%%%-------------------------------------------------------------------
-module(my_math).

%%--------------------------------------------------------------------
%% Include files
%%--------------------------------------------------------------------

%%--------------------------------------------------------------------
%% External exports
%%--------------------------------------------------------------------
-export([
]).

%%--------------------------------------------------------------------
%% Internal exports
%%--------------------------------------------------------------------
-export([
]).

%%--------------------------------------------------------------------
%% Macros
%%--------------------------------------------------------------------

%%--------------------------------------------------------------------
%% Records
%%--------------------------------------------------------------------

%%====================================================================
%% External functions
%%====================================================================
%%--------------------------------------------------------------------
%% Function:
%% Description:
%%--------------------------------------------------------------------

%%====================================================================
%% Internal functions
%%====================================================================

What should I place on external exports and what sort of functions 
should go among the internal ones? Thanks in advance.

Regards,

Quique