| 1 | <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> |
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| 2 | |
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| 3 | <!-- Copyright David Abrahams 2006. Distributed under the Boost --> |
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| 4 | <!-- Software License, Version 1.0. (See accompanying --> |
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| 5 | <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) --> |
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| 9 | "HTML Tidy for Cygwin (vers 1st April 2002), see www.w3.org"> |
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| 11 | <link rel="stylesheet" type="text/css" href="../boost.css"> |
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| 12 | |
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| 13 | <title>Boost.Python - <boost/python/data_members.hpp></title> |
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| 14 | </head> |
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| 15 | |
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| 16 | <body> |
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| 17 | <table border="0" cellpadding="7" cellspacing="0" width="100%" summary= |
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| 18 | "header"> |
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| 19 | <tr> |
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| 20 | <td valign="top" width="300"> |
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| 21 | <h3><a href="../../../../index.htm"><img height="86" width="277" |
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| 22 | alt="C++ Boost" src="../../../../boost.png" border="0"></a></h3> |
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| 23 | </td> |
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| 24 | |
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| 25 | <td valign="top"> |
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| 26 | <h1 align="center"><a href="../index.html">Boost.Python</a></h1> |
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| 27 | |
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| 28 | <h2 align="center">Header |
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| 29 | <boost/python/data_members.hpp></h2> |
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| 30 | </td> |
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| 31 | </tr> |
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| 32 | </table> |
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| 33 | <hr> |
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| 34 | |
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| 35 | <h2>Contents</h2> |
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| 36 | |
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| 37 | <dl class="page-index"> |
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| 38 | <dt><a href="#introduction">Introduction</a></dt> |
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| 39 | |
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| 40 | <dt><a href="#functions">Functions</a></dt> |
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| 41 | |
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| 42 | <dd> |
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| 43 | <dl class="page-index"> |
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| 44 | <dt><a href="#make_getter-spec">make_getter</a></dt> |
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| 45 | |
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| 46 | <dt><a href="#make_setter-spec">make_setter</a></dt> |
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| 47 | </dl> |
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| 48 | </dd> |
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| 49 | |
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| 50 | <dt><a href="#examples">Example</a></dt> |
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| 51 | </dl> |
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| 52 | <hr> |
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| 53 | |
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| 54 | <h2><a name="introduction"></a>Introduction</h2> |
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| 55 | |
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| 56 | <p><code><a href="#make_getter-spec">make_getter</a>()</code> and |
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| 57 | <code><a href="#make_setter-spec">make_setter</a>()</code> are the |
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| 58 | functions used internally by <code>class_<>::<a href= |
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| 59 | "class.html#class_-spec-modifiers">def_readonly</a></code> and |
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| 60 | <code>class_<>::<a href= |
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| 61 | "class.html#class_-spec-modifiers">def_readwrite</a></code> to produce |
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| 62 | Python callable objects which wrap C++ data members.</p> |
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| 63 | |
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| 64 | <h2><a name="functions"></a>Functions</h2> |
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| 65 | <pre> |
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| 66 | <a name="make_getter-spec">template <class C, class D></a> |
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| 67 | <a href="object.html#object-spec">object</a> make_getter(D C::*pm); |
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| 68 | |
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| 69 | template <class C, class D, class Policies> |
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| 70 | <a href= |
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| 71 | "object.html#object-spec">object</a> make_getter(D C::*pm, Policies const& policies); |
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| 72 | </pre> |
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| 73 | |
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| 74 | <dl class="function-semantics"> |
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| 75 | <dt><b>Requires:</b> <code>Policies</code> is a model of <a href= |
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| 76 | "CallPolicies.html">CallPolicies</a>.</dt> |
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| 77 | |
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| 78 | <dt><b>Effects:</b> Creates a Python callable object which accepts a |
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| 79 | single argument that can be converted <code>from_python</code> to |
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| 80 | <code>C*</code>, and returns the corresponding member <code>D</code> |
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| 81 | member of the <code>C</code> object, converted <code>to_python</code>. |
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| 82 | If <code>policies</code> is supplied, it will be applied to the |
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| 83 | function as described <a href="CallPolicies.html">here</a>. Otherwise, |
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| 84 | the library attempts to determine whether <code>D</code> is a |
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| 85 | user-defined class type, and if so uses <code><a href= |
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| 86 | "return_internal_reference.html#return_internal_reference-spec">return_internal_reference</a><></code></dt> |
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| 87 | |
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| 88 | <dt>for <code>Policies</code>. Note that this test may inappropriately |
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| 89 | choose <code>return_internal_reference<></code> in some cases |
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| 90 | when <code>D</code> is a smart pointer type. This is a known |
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| 91 | defect.</dt> |
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| 92 | |
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| 93 | <dt><b>Returns:</b> An instance of <a href= |
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| 94 | "object.html#object-spec">object</a> which holds the new Python |
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| 95 | callable object.</dt> |
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| 96 | </dl> |
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| 97 | <pre> |
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| 98 | template <class D> |
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| 99 | <a href="object.html#object-spec">object</a> make_getter(D const& d); |
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| 100 | template <class D, class Policies> |
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| 101 | <a href= |
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| 102 | "object.html#object-spec">object</a> make_getter(D const& d, Policies const& policies); |
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| 103 | |
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| 104 | template <class D> |
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| 105 | <a href="object.html#object-spec">object</a> make_getter(D const* p); |
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| 106 | template <class D, class Policies> |
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| 107 | <a href= |
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| 108 | "object.html#object-spec">object</a> make_getter(D const* p, Policies const& policies); |
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| 109 | </pre> |
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| 110 | |
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| 111 | <dl class="function-semantics"> |
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| 112 | <dt><b>Requires:</b> <code>Policies</code> is a model of <a href= |
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| 113 | "CallPolicies.html">CallPolicies</a>.</dt> |
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| 114 | |
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| 115 | <dt><b>Effects:</b> Creates a Python callable object which accepts no |
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| 116 | arguments and returns <code>d</code> or <code>*p</code>, converted |
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| 117 | <code>to_python</code> on demand. If <code>policies</code> is supplied, |
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| 118 | it will be applied to the function as described <a href= |
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| 119 | "CallPolicies.html">here</a>. Otherwise, the library attempts to |
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| 120 | determine whether <code>D</code> is a user-defined class type, and if |
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| 121 | so uses <code><a href= |
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| 122 | "reference_existing_object.html#reference_existing_object-spec">reference_existing_object</a></code></dt> |
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| 123 | |
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| 124 | <dt>for <code>Policies</code>.</dt> |
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| 125 | |
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| 126 | <dt><b>Returns:</b> An instance of <a href= |
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| 127 | "object.html#object-spec">object</a> which holds the new Python |
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| 128 | callable object.</dt> |
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| 129 | </dl> |
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| 130 | <pre> |
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| 131 | <a name="make_setter-spec">template <class C, class D></a> |
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| 132 | <a href="object.html#object-spec">object</a> make_setter(D C::*pm); |
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| 133 | |
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| 134 | template <class C, class D, class Policies> |
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| 135 | <a href= |
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| 136 | "object.html#object-spec">object</a> make_setter(D C::*pm, Policies const& policies); |
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| 137 | </pre> |
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| 138 | |
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| 139 | <dl class="function*-semantics"> |
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| 140 | <dt><b>Requires:</b> <code>Policies</code> is a model of <a href= |
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| 141 | "CallPolicies.html">CallPolicies</a>.</dt> |
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| 142 | |
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| 143 | <dt><b>Effects:</b> Creates a Python callable object which, when called |
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| 144 | from Python, expects two arguments which can be converted |
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| 145 | <code>from_python</code> to <code>C*</code> and |
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| 146 | <code>D const&</code>, respectively, and sets the |
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| 147 | corresponding <code>D</code> member of the <code>C</code> object. If |
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| 148 | <code>policies</code> is supplied, it will be applied to the function |
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| 149 | as described <a href="CallPolicies.html">here</a>.</dt> |
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| 150 | |
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| 151 | <dt><b>Returns:</b> An instance of <a href= |
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| 152 | "object.html#object-spec">object</a> which holds the new Python |
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| 153 | callable object.</dt> |
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| 154 | </dl> |
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| 155 | <pre> |
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| 156 | template <class D> |
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| 157 | <a href="object.html#object-spec">object</a> make_setter(D& d); |
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| 158 | template <class D, class Policies> |
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| 159 | <a href= |
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| 160 | "object.html#object-spec">object</a> make_setter(D& d, Policies const& policies); |
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| 161 | |
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| 162 | template <class D> |
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| 163 | <a href="object.html#object-spec">object</a> make_setter(D* p); |
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| 164 | template <class D, class Policies> |
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| 165 | <a href= |
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| 166 | "object.html#object-spec">object</a> make_setter(D* p, Policies const& policies); |
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| 167 | </pre> |
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| 168 | |
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| 169 | <dl class="function-semantics"> |
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| 170 | <dt><b>Requires:</b> <code>Policies</code> is a model of <a href= |
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| 171 | "CallPolicies.html">CallPolicies</a>.</dt> |
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| 172 | |
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| 173 | <dt><b>Effects:</b> Creates a Python callable object which accepts one |
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| 174 | argument, which is converted from Python to <code>D const&</code> |
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| 175 | and written into <code>d</code> or <code>*p</code>, respectively. If |
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| 176 | <code>policies</code> is supplied, it will be applied to the function |
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| 177 | as described <a href="CallPolicies.html">here</a>.</dt> |
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| 178 | |
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| 179 | <dt><b>Returns:</b> An instance of <a href= |
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| 180 | "object.html#object-spec">object</a> which holds the new Python |
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| 181 | callable object.</dt> |
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| 182 | </dl> |
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| 183 | |
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| 184 | <h2><a name="examples"></a>Example</h2> |
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| 185 | |
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| 186 | <p>The code below uses make_getter and make_setter to expose a data |
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| 187 | member as functions:</p> |
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| 188 | <pre> |
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| 189 | #include <boost/python/data_members.hpp> |
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| 190 | #include <boost/python/module.hpp> |
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| 191 | #include <boost/python/class.hpp> |
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| 192 | |
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| 193 | struct X |
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| 194 | { |
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| 195 | X(int x) : y(x) {} |
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| 196 | int y; |
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| 197 | }; |
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| 198 | |
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| 199 | using namespace boost::python; |
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| 200 | |
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| 201 | BOOST_PYTHON_MODULE_INIT(data_members_example) |
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| 202 | { |
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| 203 | class_<X>("X", init<int>()) |
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| 204 | .def("get", make_getter(&X::y)) |
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| 205 | .def("set", make_setter(&X::y)) |
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| 206 | ; |
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| 207 | } |
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| 208 | </pre> |
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| 209 | It can be used this way in Python: |
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| 210 | <pre> |
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| 211 | >>> from data_members_example import * |
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| 212 | >>> x = X(1) |
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| 213 | >>> x.get() |
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| 214 | 1 |
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| 215 | >>> x.set(2) |
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| 216 | >>> x.get() |
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| 217 | 2 |
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| 218 | </pre> |
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| 219 | |
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| 220 | <p> |
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| 221 | <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan --> |
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| 222 | 5 August, 2003 <!--webbot bot="Timestamp" endspan i-checksum="39359" --> |
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| 223 | </p> |
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| 224 | |
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| 225 | <p><i>© Copyright <a href= |
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| 226 | "../../../../people/dave_abrahams.htm">Dave Abrahams</a> 2002.</i></p> |
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| 227 | </body> |
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| 228 | </html> |
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| 229 | |
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