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
107
108
109
110
111
112
113
114
115
116
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<meta name="generator" content="HTML Tidy, see www.w3.org">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link rel="stylesheet" type="text/css" href="../boost.css">
<title>Boost.Python - <boost/python/pointee.hpp></title>
<table border="0" cellpadding="7" cellspacing="0" width="100%" summary=
"header">
<tr>
<td valign="top" width="300">
<h3><a href="../../../../index.htm"><img height="86" width="277" alt=
"C++ Boost" src="../../../../boost.png" border="0"></a></h3>
<td valign="top">
<h1 align="center"><a href="../index.html">Boost.Python</a></h1>
<h2 align="center">Header <boost/python/pointee.hpp></h2>
</table>
<hr>
<h2>Contents</h2>
<dl class="page-index">
<dt><a href="#introduction">Introduction</a>
<dt><a href="#classes">Classes</a>
<dd>
<dl class="page-index">
<dt><a href="#pointee-spec">Class Template<code>pointee</code></a>
<dd>
<dl class="page-index">
<dt><a href="#pointee-spec-synopsis">Class Template
<code>pointee</code> synopsis</a>
</dl>
</dl>
<dt><a href="#examples">Example</a>
</dl>
<hr>
<h2><a name="introduction"></a>Introduction</h2>
<p><code><boost/python/pointee.hpp></code> introduces a
traits <a
href="../../../mpl/doc/refmanual/metafunction.html">metafunction</a>
template <code>pointee<T></code> that can be used to extract the "pointed-to" type from the type of a pointer or smart pointer.
<h2><a name="classes"></a>Classes</h2>
<h3><a name="pointee-spec"></a>Class Template <code>pointee<class T></code></h3>
<p><code>pointee<T></code> is used by the <code><a
href="class.html#class_-spec">class_</a><...></code>
template to deduce the type being held when a pointer or smart
pointer type is used as its <code>HeldType</code> argument.
<h4><a name="pointee-spec-synopsis"></a>Class Template
<code>pointee</code> synopsis</h4>
<pre>
namespace boost { namespace python
{
template <class T> struct pointee
{
typedef T::element_type type;
};
// specialization for pointers
template <T> struct pointee<T*>
{
typedef T type;
};
}
</pre>
<h2><a name="examples"></a>Example</h2>
Given a 3rd-party smart pointer type
<code>smart_pointer<T></code>, one might partially specialize
<code>pointee<smart_pointer<T> ></code> so that it can be
used as the <code>HeldType</code> for a class wrapper:
<pre>
#include <boost/python/pointee.hpp>
#include <boost/python/class.hpp>
#include <third_party_lib.hpp>
namespace boost { namespace python
{
template <class T> struct pointee<smart_pointer<T> >
{
typedef T type;
};
}}
BOOST_PYTHON_MODULE(pointee_demo)
{
class_<third_party_class, smart_pointer<third_party_class> >("third_party_class")
.def(...)
...
;
}
</pre>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
13 November, 2002
<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
<p><i>© Copyright <a href="../../../../people/dave_abrahams.htm">Dave
Abrahams</a> 2002. </i>
|
