1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Binding Member Variables</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Chapter 1. Phoenix 3.2.0"> 8<link rel="up" href="../bind.html" title="Bind"> 9<link rel="prev" href="binding_member_functions.html" title="Binding Member Functions"> 10<link rel="next" href="compatibility_with_boost_bind.html" title="Compatibility with Boost.Bind"> 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="binding_member_functions.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../bind.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="compatibility_with_boost_bind.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="phoenix.modules.bind.binding_member_variables"></a><a class="link" href="binding_member_variables.html" title="Binding Member Variables">Binding 28 Member Variables</a> 29</h4></div></div></div> 30<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">phoenix</span><span class="special">/</span><span class="identifier">bind</span><span class="special">/</span><span class="identifier">bind_member_variable</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 31</pre> 32<p> 33 Member variables can also be bound much like member functions. Member variables 34 are not functions. Yet, like the <a class="link" href="../core/references.html" title="References"><code class="computeroutput"><span class="identifier">ref</span><span class="special">(</span><span class="identifier">x</span><span class="special">)</span></code></a> 35 that acts like a nullary function returning a reference to the data, member 36 variables, when bound, act like a unary function, taking in a pointer or 37 reference to an object as its argument and returning a reference to the 38 bound member variable. For instance, given: 39 </p> 40<pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">xyz</span> 41<span class="special">{</span> 42 <span class="keyword">int</span> <span class="identifier">v</span><span class="special">;</span> 43<span class="special">};</span> 44</pre> 45<p> 46 <code class="computeroutput"><span class="identifier">xyz</span><span class="special">::</span><span class="identifier">v</span></code> can be bound as: 47 </p> 48<pre class="programlisting"><span class="identifier">bind</span><span class="special">(&</span><span class="identifier">xyz</span><span class="special">::</span><span class="identifier">v</span><span class="special">,</span> <span class="identifier">obj</span><span class="special">)</span> <span class="comment">// obj is an xyz object</span> 49</pre> 50<p> 51 As noted, just like the bound member function, a bound member variable 52 also expects the first (and only) argument to be a pointer or reference 53 to an object. The object (reference or pointer) can be lazily bound. Examples: 54 </p> 55<pre class="programlisting"><span class="identifier">xyz</span> <span class="identifier">obj</span><span class="special">;</span> 56<span class="identifier">bind</span><span class="special">(&</span><span class="identifier">xyz</span><span class="special">::</span><span class="identifier">v</span><span class="special">,</span> <span class="identifier">arg1</span><span class="special">)</span> <span class="comment">// arg1.v</span> 57<span class="identifier">bind</span><span class="special">(&</span><span class="identifier">xyz</span><span class="special">::</span><span class="identifier">v</span><span class="special">,</span> <span class="identifier">obj</span><span class="special">)</span> <span class="comment">// obj.v</span> 58<span class="identifier">bind</span><span class="special">(&</span><span class="identifier">xyz</span><span class="special">::</span><span class="identifier">v</span><span class="special">,</span> <span class="identifier">arg1</span><span class="special">)(</span><span class="identifier">obj</span><span class="special">)</span> <span class="special">=</span> <span class="number">4</span> <span class="comment">// obj.v = 4</span> 59</pre> 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="binding_member_functions.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../bind.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="compatibility_with_boost_bind.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 73</div> 74</body> 75</html> 76
