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1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> 5<title>References</title> 6<link rel="stylesheet" href="../../../boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> 8<link rel="home" href="../../../index.html" title="Chapter 1. Phoenix 3.0"> 9<link rel="up" href="../primitives.html" title="Primitives"> 10<link rel="prev" href="values.html" title="Values"> 11<link rel="next" href="arguments.html" title="Arguments"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr><td valign="top"></td></tr></table> 15<hr> 16<div class="spirit-nav"> 17<a accesskey="p" href="values.html"><img src="../../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../primitives.html"><img src="../../../images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../images/home.png" alt="Home"></a><a accesskey="n" href="arguments.html"><img src="../../../images/next.png" alt="Next"></a> 18</div> 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">&</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">*&</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> 52</div> 53</div> 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 © 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>) 59 </p> 60</div></td> 61</tr></table> 62<hr> 63<div class="spirit-nav"> 64<a accesskey="p" href="values.html"><img src="../../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../primitives.html"><img src="../../../images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../images/home.png" alt="Home"></a><a accesskey="n" href="arguments.html"><img src="../../../images/next.png" alt="Next"></a> 65</div> 66</body> 67</html>