libs/python/doc/html/reference/utility_and_infrastructure/boost_python_pointee_hpp.html


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=US-ASCII">
<title>boost/python/pointee.hpp</title>
<link rel="stylesheet" href="../../boostbook.css" type="text/css">
<meta name="generator" content="DocBook XSL Stylesheets V1.76.1">
<link rel="home" href="../index.html" title="Boost.Python Reference Manual">
<link rel="up" href="../utility_and_infrastructure.html" title="Chapter&#160;7.&#160;Utility and Infrastructure">
<link rel="prev" href="boost_python_instance_holder_hpp.html" title="boost/python/instance_holder.hpp">
<link rel="next" href="boost_python_handle_hpp.html" title="boost/python/handle.hpp">
</head>
<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF">
<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="" width="" height="" src="../../images/boost.png"></td></tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="boost_python_instance_holder_hpp.html"><img src="../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../utility_and_infrastructure.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="boost_python_handle_hpp.html"><img src="../../images/next.png" alt="Next"></a>
</div>
<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="utility_and_infrastructure.boost_python_pointee_hpp"></a><a class="link" href="boost_python_pointee_hpp.html" title="boost/python/pointee.hpp">boost/python/pointee.hpp</a>
</h2></div></div></div>
<div class="toc"><dl>
<dt><span class="section"><a href="boost_python_pointee_hpp.html#utility_and_infrastructure.boost_python_pointee_hpp.introduction">Introduction</a></span></dt>
<dt><span class="section"><a href="boost_python_pointee_hpp.html#utility_and_infrastructure.boost_python_pointee_hpp.class_template_pointee">Class
        template <code class="computeroutput"><span class="identifier">pointee</span></code></a></span></dt>
<dt><span class="section"><a href="boost_python_pointee_hpp.html#utility_and_infrastructure.boost_python_pointee_hpp.examples">Examples</a></span></dt>
</dl></div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="utility_and_infrastructure.boost_python_pointee_hpp.introduction"></a><a class="link" href="boost_python_pointee_hpp.html#utility_and_infrastructure.boost_python_pointee_hpp.introduction" title="Introduction">Introduction</a>
</h3></div></div></div>
<p>
          &lt;boost/python/pointee.hpp&gt; introduces a traits metafunction <code class="computeroutput"><span class="keyword">template</span> <span class="identifier">pointee</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span></code> that can be used to extract the "pointed-to"
          type from the type of a pointer or smart pointer.
        </p>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="utility_and_infrastructure.boost_python_pointee_hpp.class_template_pointee"></a><a class="link" href="boost_python_pointee_hpp.html#utility_and_infrastructure.boost_python_pointee_hpp.class_template_pointee" title="Class template pointee">Class
        template <code class="computeroutput"><span class="identifier">pointee</span></code></a>
</h3></div></div></div>
<p>
          <code class="computeroutput"><span class="identifier">pointee</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span></code>
          is used by the <a class="link" href="../high_level_components.html#high_level_components.boost_python_class_hpp.class_template_class_t_bases_hel" title="Class template class_&lt;T, Bases, HeldType, NonCopyable&gt;"><code class="computeroutput"><span class="identifier">class_</span><span class="special">&lt;...&gt;</span></code></a>
          template to deduce the type being held when a pointer or smart pointer
          type is used as its HeldType argument.
        </p>
<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">python</span>
<span class="special">{</span>
   <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">struct</span> <span class="identifier">pointee</span>
   <span class="special">{</span>
      <span class="keyword">typedef</span> <span class="identifier">T</span><span class="special">::</span><span class="identifier">element_type</span> <span class="identifier">type</span><span class="special">;</span>
   <span class="special">};</span>

   <span class="comment">// specialization for pointers</span>
   <span class="keyword">template</span> <span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">struct</span> <span class="identifier">pointee</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">*&gt;</span>
   <span class="special">{</span>
      <span class="keyword">typedef</span> <span class="identifier">T</span> <span class="identifier">type</span><span class="special">;</span>
   <span class="special">};</span>
<span class="special">}</span>
</pre>
</div>
<div class="section">
<div class="titlepage"><div><div><h3 class="title">
<a name="utility_and_infrastructure.boost_python_pointee_hpp.examples"></a><a class="link" href="boost_python_pointee_hpp.html#utility_and_infrastructure.boost_python_pointee_hpp.examples" title="Examples">Examples</a>
</h3></div></div></div>
<p>
          Given a 3rd-party smart pointer type <code class="computeroutput"><span class="identifier">smart_pointer</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span></code>, one might partially specialize <code class="computeroutput"><span class="identifier">pointee</span><span class="special">&lt;</span><span class="identifier">smart_pointer</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="special">&gt;</span></code> so that it can be used as the HeldType
          for a class wrapper:
        </p>
<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="identifier">pointee</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="keyword">class</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
<span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">third_party_lib</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>

<span class="keyword">namespace</span> <span class="identifier">boost</span> <span class="special">{</span> <span class="keyword">namespace</span> <span class="identifier">python</span>
<span class="special">{</span>
  <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">struct</span> <span class="identifier">pointee</span><span class="special">&lt;</span><span class="identifier">smart_pointer</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span> <span class="special">&gt;</span>
  <span class="special">{</span>
     <span class="keyword">typedef</span> <span class="identifier">T</span> <span class="identifier">type</span><span class="special">;</span>
  <span class="special">};</span>
<span class="special">}}</span>

<span class="identifier">BOOST_PYTHON_MODULE</span><span class="special">(</span><span class="identifier">pointee_demo</span><span class="special">)</span>
<span class="special">{</span>
   <span class="identifier">class_</span><span class="special">&lt;</span><span class="identifier">third_party_class</span><span class="special">,</span> <span class="identifier">smart_pointer</span><span class="special">&lt;</span><span class="identifier">third_party_class</span><span class="special">&gt;</span> <span class="special">&gt;(</span><span class="string">"third_party_class"</span><span class="special">)</span>
      <span class="special">.</span><span class="identifier">def</span><span class="special">(...)</span>
      <span class="special">...</span>
      <span class="special">;</span>
<span class="special">}</span>
</pre>
</div>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
<td align="left"></td>
<td align="right"><div class="copyright-footer">Copyright &#169; 2002-2005, 2015 David Abrahams, Stefan Seefeld<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        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>
      </p>
</div></td>
</tr></table>
<hr>
<div class="spirit-nav">
<a accesskey="p" href="boost_python_instance_holder_hpp.html"><img src="../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../utility_and_infrastructure.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="boost_python_handle_hpp.html"><img src="../../images/next.png" alt="Next"></a>
</div>
</body>
</html>