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1 | <html> |
| 2 | <head> | |
| 3 | <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> | |
| 4 | <title>References</title> | |
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| 7 | <link rel="home" href="../../index.html" title="Chapter 1. Phoenix 3.2.0"> | |
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| 13 | <table cellpadding="2" width="100%"><tr> | |
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| 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">&</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">*&</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 © 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> |