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<chapter>
  <header>
    <copyright>
      <year>2000</year><year>2009</year>
      <holder>Ericsson AB. All Rights Reserved.</holder>
    </copyright>
    <legalnotice>
      The contents of this file are subject to the Erlang Public License,
      Version 1.1, (the "License"); you may not use this file except in
      compliance with the License. You should have received a copy of the
      Erlang Public License along with this software. If not, it can be
      retrieved online at http://www.erlang.org/.
    
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      basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
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    <title>Problem Example</title>
    <prepared></prepared>
    <docno></docno>
    <date></date>
    <rev></rev>
    <file>example.xml</file>
  </header>

  <section>
    <title>Description</title>
    <p>A common interoperability situation is when there exists a piece of code solving some complex problem, and we would like to incorporate this piece of code in our Erlang program. Suppose for example we have the following C functions that we would like to be able to call from Erlang.</p>
    <codeinclude file="complex.c" tag="" type="none"></codeinclude>
    <p>(For the sake of keeping the example as simple as possible, the functions are not very complicated in this case).</p>
    <p>Preferably we would like to able to call <c>foo</c> and <c>bar</c> without having to bother about them actually being C functions.</p>
    <pre>
% Erlang code
...
Res = complex:foo(X),
...</pre>
    <p>The communication with C is hidden in the implementation of <c>complex.erl</c>. In the following chapters it is shown how this module can be implemented using the different interoperability mechanisms.</p>
  </section>
</chapter>

