ceph/src/boost/libs/phoenix/doc/html/phoenix/starter_kit/references.html

   1 <html>
   2 <head>
   3 <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
   4 <title>References</title>
   5 <link rel="stylesheet" href="../../../../../../doc/src/boostbook.css" type="text/css">
   6 <meta name="generator" content="DocBook XSL Stylesheets V1.75.2">
   7 <link rel="home" href="../../index.html" title="Chapter&#160;1.&#160;Phoenix 3.2.0">
   8 <link rel="up" href="../starter_kit.html" title="Starter Kit">
   9 <link rel="prev" href="values.html" title="Values">
  10 <link rel="next" href="arguments.html" title="Arguments">
  11 </head>
  12 <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
  13 <table cellpadding="2" width="100%"><tr>
  14 <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../boost.png"></td>
  15 <td align="center"><a href="../../../../../../index.html">Home</a></td>
  16 <td align="center"><a href="../../../../../../libs/libraries.htm">Libraries</a></td>
  17 <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td>
  18 <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td>
  19 <td align="center"><a href="../../../../../../more/index.htm">More</a></td>
  20 </tr></table>
  21 <hr>
  22 <div class="spirit-nav">
  23 <a accesskey="p" href="values.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../starter_kit.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="arguments.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
  24 </div>
  25 <div class="section">
  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="phoenix.starter_kit.references"></a><a class="link" href="references.html" title="References">References</a>
  28 </h3></div></div></div>
  29 <p>
  30         References are functions. They hold a reference to a value stored somewhere.
  31         For example, given:
  32       </p>
  33 <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>
  34 <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>
  35 </pre>
  36 <p>
  37         we create <code class="computeroutput"><span class="identifier">references</span></code> to
  38         <code class="computeroutput"><span class="identifier">i</span></code> and <code class="computeroutput"><span class="identifier">s</span></code>
  39         this way:
  40       </p>
  41 <pre class="programlisting"><span class="identifier">ref</span><span class="special">(</span><span class="identifier">i</span><span class="special">)</span>
  42 <span class="identifier">ref</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span>
  43 </pre>
  44 <p>
  45         Like <code class="computeroutput"><span class="identifier">val</span></code>, the expressions
  46         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>,
  47         and the second one returning a <code class="computeroutput"><span class="keyword">char</span>
  48         <span class="keyword">const</span><span class="special">*&amp;</span></code>.
  49       </p>
  50 <p>
  51         (See <a href="../../../../example/references.cpp" target="_top">references.cpp</a>)
  52       </p>
  53 <div class="sidebar">
  54 <p class="title"><b></b></p>
  55 <p>
  56         <span class="inlinemediaobject"><img src="../../images/tip.png"></span>
  57         Learn more about references <a class="link" href="../modules/core/references.html" title="References">here.</a>
  58       </p>
  59 </div>
  60 </div>
  61 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
  62 <td align="left"></td>
  63 <td align="right"><div class="copyright-footer">Copyright &#169; 2002-2005, 2010, 2014, 2015 Joel de Guzman, Dan Marsden, Thomas
  64       Heller, John Fletcher<p>
  65         Distributed under the Boost Software License, Version 1.0. (See accompanying
  66         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>)
  67       </p>
  68 </div></td>
  69 </tr></table>
  70 <hr>
  71 <div class="spirit-nav">
  72 <a accesskey="p" href="values.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../starter_kit.html"><img src="../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../index.html"><img src="../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="arguments.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a>
  73 </div>
  74 </body>
  75 </html>