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  5. <title>References</title>
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  19. <div class="section">
  20. <div class="titlepage"><div><div><h4 class="title">
  21. <a name="phoenix.starter_kit.primitives.references"></a><a class="link" href="references.html" title="References">References</a>
  22. </h4></div></div></div>
  23. <p>
  24. References are functions. They hold a reference to a value stored somewhere.
  25. For example, given:
  26. </p>
  27. <pre class="programlisting"><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">3</span><span class="special">;</span>
  28. <span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">s</span> <span class="special">=</span> <span class="string">"Hello World"</span><span class="special">;</span>
  29. </pre>
  30. <p>
  31. we create <code class="computeroutput"><span class="identifier">references</span></code> to
  32. <code class="computeroutput"><span class="identifier">i</span></code> and <code class="computeroutput"><span class="identifier">s</span></code>
  33. this way:
  34. </p>
  35. <pre class="programlisting"><span class="identifier">ref</span><span class="special">(</span><span class="identifier">i</span><span class="special">)</span>
  36. <span class="identifier">ref</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span>
  37. </pre>
  38. <p>
  39. Like <code class="computeroutput"><span class="identifier">val</span></code>, the expressions
  40. above evaluates to a nullary function; the first one returning an <code class="computeroutput"><span class="keyword">int</span><span class="special">&amp;</span></code>,
  41. and the second one returning a <code class="computeroutput"><span class="keyword">char</span>
  42. <span class="keyword">const</span><span class="special">*&amp;</span></code>.
  43. </p>
  44. <p>
  45. (See <a href="../../../../../example/references.cpp" target="_top">references.cpp</a>)
  46. </p>
  47. <div class="sidebar">
  48. <div class="titlepage"></div>
  49. <p>
  50. <span class="inlinemediaobject"><img src="../../../images/tip.png" alt="tip"></span> Learn more about references <a class="link" href="../../modules/core/references.html" title="References">here.</a>
  51. </p>
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  54. <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
  55. <td align="left"></td>
  56. <td align="right"><div class="copyright-footer">Copyright &#169; 2002-2005, 2010 Joel de Guzman, Dan Marsden, Thomas Heller<p>
  57. Distributed under the Boost Software License, Version 1.0. (See accompanying
  58. file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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