1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Models of CallPolicies</title> 5<link rel="stylesheet" href="../../boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../index.html" title="Boost.Python Reference Manual"> 8<link rel="up" href="../function_invocation_and_creation.html" title="Chapter 4. Function Invocation and Creation"> 9<link rel="prev" href="function_documentation.html" title="Function documentation"> 10<link rel="next" href="models_of_resultconverter.html" title="Models of ResultConverter"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr><td valign="top"><img alt="" width="" height="" src="../../images/boost.png"></td></tr></table> 14<hr> 15<div class="spirit-nav"> 16<a accesskey="p" href="function_documentation.html"><img src="../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../function_invocation_and_creation.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="models_of_resultconverter.html"><img src="../../images/next.png" alt="Next"></a> 17</div> 18<div class="section"> 19<div class="titlepage"><div><div><h2 class="title" style="clear: both"> 20<a name="function_invocation_and_creation.models_of_callpolicies"></a><a class="link" href="models_of_callpolicies.html" title="Models of CallPolicies">Models 21 of CallPolicies</a> 22</h2></div></div></div> 23<div class="toc"><dl class="toc"> 24<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici">boost/python/default_call_policies.hpp</a></span></dt> 25<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp">boost/python/return_arg.hpp</a></span></dt> 26<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref">boost/python/return_internal_reference.hpp</a></span></dt> 27<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy">boost/python/return_value_policy.hpp</a></span></dt> 28<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_">boost/python/with_custodian_and_ward.hpp</a></span></dt> 29</dl></div> 30<div class="section"> 31<div class="titlepage"><div><div><h3 class="title"> 32<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici" title="boost/python/default_call_policies.hpp">boost/python/default_call_policies.hpp</a> 33</h3></div></div></div> 34<div class="toc"><dl class="toc"> 35<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_call_policies">Class 36 <code class="computeroutput"><span class="identifier">default_call_policies</span></code></a></span></dt> 37<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_call_policies_stat">Class 38 <code class="computeroutput"><span class="identifier">default_call_policies</span></code> static 39 functions</a></span></dt> 40<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_result_converter">Class 41 <code class="computeroutput"><span class="identifier">default_result_converter</span></code></a></span></dt> 42<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_result_converter_m">Class 43 <code class="computeroutput"><span class="identifier">default_result_converter</span></code> 44 metafunctions</a></span></dt> 45<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.example">Example</a></span></dt> 46</dl></div> 47<div class="section"> 48<div class="titlepage"><div><div><h4 class="title"> 49<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_call_policies"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_call_policies" title="Class default_call_policies">Class 50 <code class="computeroutput"><span class="identifier">default_call_policies</span></code></a> 51</h4></div></div></div> 52<p> 53 <code class="computeroutput"><span class="identifier">default_call_policies</span></code> 54 is a model of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> 55 with no <code class="computeroutput"><span class="identifier">precall</span></code> or <code class="computeroutput"><span class="identifier">postcall</span></code> behavior and a <code class="computeroutput"><span class="identifier">result_converter</span></code> which handles by-value 56 returns. Wrapped C++ functions and member functions <code class="computeroutput"><span class="identifier">use</span> 57 <span class="identifier">default_call_policies</span></code> unless 58 otherwise specified. You may find it convenient to derive new models 59 of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> 60 from <code class="computeroutput"><span class="identifier">default_call_policies</span></code>. 61 </p> 62<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> 63<span class="special">{</span> 64 <span class="keyword">struct</span> <span class="identifier">default_call_policies</span> 65 <span class="special">{</span> 66 <span class="keyword">static</span> <span class="keyword">bool</span> <span class="identifier">precall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*);</span> 67 <span class="keyword">static</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">postcall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*,</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">result</span><span class="special">);</span> 68 <span class="keyword">typedef</span> <span class="identifier">default_result_converter</span> <span class="identifier">result_converter</span><span class="special">;</span> 69 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Sig</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">extract_return_type</span> <span class="special">:</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">front</span><span class="special"><</span><span class="identifier">Sig</span><span class="special">>{};</span> 70 <span class="special">};</span> 71<span class="special">}}</span> 72</pre> 73</div> 74<div class="section"> 75<div class="titlepage"><div><div><h4 class="title"> 76<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_call_policies_stat"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_call_policies_stat" title="Class default_call_policies static functions">Class 77 <code class="computeroutput"><span class="identifier">default_call_policies</span></code> static 78 functions</a> 79</h4></div></div></div> 80<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">precall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*);</span></pre> 81<div class="variablelist"> 82<p class="title"><b></b></p> 83<dl class="variablelist"> 84<dt><span class="term">Returns</span></dt> 85<dd><p> 86 true 87 </p></dd> 88<dt><span class="term">Throws</span></dt> 89<dd><p> 90 nothing 91 </p></dd> 92</dl> 93</div> 94<pre class="programlisting"><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">postcall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*,</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">result</span><span class="special">);</span></pre> 95<div class="variablelist"> 96<p class="title"><b></b></p> 97<dl class="variablelist"> 98<dt><span class="term">Returns</span></dt> 99<dd><p> 100 result 101 </p></dd> 102<dt><span class="term">Throws</span></dt> 103<dd><p> 104 nothing 105 </p></dd> 106</dl> 107</div> 108</div> 109<div class="section"> 110<div class="titlepage"><div><div><h4 class="title"> 111<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_result_converter"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_result_converter" title="Class default_result_converter">Class 112 <code class="computeroutput"><span class="identifier">default_result_converter</span></code></a> 113</h4></div></div></div> 114<p> 115 default_result_converter is a model of <a class="link" href="../concepts/resultconverter.html#concepts.resultconverter.resultconvertergenerator_concept" title="ResultConverterGenerator Concept Requirements"><code class="computeroutput"><span class="identifier">ResultConverterGenerator</span></code></a> which 116 can be used to wrap C++ functions returning non-pointer types, <code class="computeroutput"><span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span></code>, and <code class="computeroutput"><span class="identifier">PyObject</span><span class="special">*</span></code>, by-value. 117 </p> 118<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> 119<span class="special">{</span> 120 <span class="keyword">struct</span> <span class="identifier">default_result_converter</span> 121 <span class="special">{</span> 122 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">apply</span><span class="special">;</span> 123 <span class="special">};</span> 124<span class="special">}}</span> 125</pre> 126</div> 127<div class="section"> 128<div class="titlepage"><div><div><h4 class="title"> 129<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_result_converter_m"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.class_default_result_converter_m" title="Class default_result_converter metafunctions">Class 130 <code class="computeroutput"><span class="identifier">default_result_converter</span></code> 131 metafunctions</a> 132</h4></div></div></div> 133<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">apply</span></pre> 134<div class="variablelist"> 135<p class="title"><b></b></p> 136<dl class="variablelist"> 137<dt><span class="term">Requires</span></dt> 138<dd><p> 139 T is not a reference type. If T is a pointer type, T is const char* 140 or PyObject*. 141 </p></dd> 142<dt><span class="term">Returns</span></dt> 143<dd><p> 144 typedef to_python_value<T const&> type; 145 </p></dd> 146</dl> 147</div> 148</div> 149<div class="section"> 150<div class="titlepage"><div><div><h4 class="title"> 151<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.example"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_default_call_polici.example" title="Example">Example</a> 152</h4></div></div></div> 153<p> 154 This example comes from the Boost.Python implementation itself. Because 155 the return_value_policy class template does not implement precall or 156 postcall behavior, its default base class is default_call_policies: 157 </p> 158<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Handler</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span> <span class="special">=</span> <span class="identifier">default_call_policies</span><span class="special">></span> 159<span class="keyword">struct</span> <span class="identifier">return_value_policy</span> <span class="special">:</span> <span class="identifier">Base</span> 160<span class="special">{</span> 161 <span class="keyword">typedef</span> <span class="identifier">Handler</span> <span class="identifier">result_converter</span><span class="special">;</span> 162<span class="special">};</span> 163</pre> 164</div> 165</div> 166<div class="section"> 167<div class="titlepage"><div><div><h3 class="title"> 168<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp" title="boost/python/return_arg.hpp">boost/python/return_arg.hpp</a> 169</h3></div></div></div> 170<div class="toc"><dl class="toc"> 171<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.introduction">Introduction</a></span></dt> 172<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_return_arg">Class 173 <code class="computeroutput"><span class="identifier">return_arg</span></code></a></span></dt> 174<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_return_arg_static_function">Class 175 <code class="computeroutput"><span class="identifier">return_arg</span></code> static functions</a></span></dt> 176<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_template_return_self">Class 177 template <code class="computeroutput"><span class="identifier">return_self</span></code></a></span></dt> 178<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.example">Example</a></span></dt> 179</dl></div> 180<div class="section"> 181<div class="titlepage"><div><div><h4 class="title"> 182<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.introduction"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.introduction" title="Introduction">Introduction</a> 183</h4></div></div></div> 184<p> 185 <code class="computeroutput"><span class="identifier">return_arg</span></code> and <code class="computeroutput"><span class="identifier">return_self</span></code> instantiations are models 186 of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> 187 which return the specified argument parameter (usually <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>) 188 of a wrapped (member) function. 189 </p> 190</div> 191<div class="section"> 192<div class="titlepage"><div><div><h4 class="title"> 193<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_return_arg"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_return_arg" title="Class return_arg">Class 194 <code class="computeroutput"><span class="identifier">return_arg</span></code></a> 195</h4></div></div></div> 196<div class="informaltable"><table class="table"> 197<colgroup> 198<col> 199<col> 200<col> 201<col> 202</colgroup> 203<thead><tr> 204<th> 205 <p> 206 Parameter 207 </p> 208 </th> 209<th> 210 <p> 211 Requirements 212 </p> 213 </th> 214<th> 215 <p> 216 Description 217 </p> 218 </th> 219<th> 220 <p> 221 Default 222 </p> 223 </th> 224</tr></thead> 225<tbody> 226<tr> 227<td> 228 <p> 229 arg_pos 230 </p> 231 </td> 232<td> 233 <p> 234 A positive compile-time constant of type <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>. 235 </p> 236 </td> 237<td> 238 <p> 239 the position of the argument to be returned. 240 </p> 241 </td> 242<td> 243 <p> 244 1 245 </p> 246 </td> 247</tr> 248<tr> 249<td> 250 <p> 251 Base 252 </p> 253 </td> 254<td> 255 <p> 256 A model of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> 257 </p> 258 </td> 259<td> 260 <p> 261 Used for policy composition. Any <code class="computeroutput"><span class="identifier">result_converter</span></code> 262 it supplies will be overridden by <code class="computeroutput"><span class="identifier">return_arg</span></code>, 263 but its <code class="computeroutput"><span class="identifier">precall</span></code> 264 and <code class="computeroutput"><span class="identifier">postcall</span></code> 265 policies are composed as described here <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a>. 266 </p> 267 </td> 268<td> 269 <p> 270 default_call_policies 271 </p> 272 </td> 273</tr> 274</tbody> 275</table></div> 276<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> 277<span class="special">{</span> 278 <span class="keyword">template</span> <span class="special"><</span><span class="identifier">size_t</span> <span class="identifier">arg_pos</span><span class="special">=</span><span class="number">1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span> <span class="special">=</span> <span class="identifier">default_call_policies</span><span class="special">></span> 279 <span class="keyword">struct</span> <span class="identifier">return_arg</span> <span class="special">:</span> <span class="identifier">Base</span> 280 <span class="special">{</span> 281 <span class="keyword">static</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">postcall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*,</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">result</span><span class="special">);</span> 282 <span class="keyword">struct</span> <span class="identifier">result_converter</span><span class="special">{</span> <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">T</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">apply</span><span class="special">;</span> <span class="special">};</span> 283 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Sig</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">extract_return_type</span> <span class="special">:</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">at_c</span><span class="special"><</span><span class="identifier">Sig</span><span class="special">,</span> <span class="identifier">arg_pos</span><span class="special">>{};</span> 284 285 <span class="special">};</span> 286<span class="special">}}</span> 287</pre> 288</div> 289<div class="section"> 290<div class="titlepage"><div><div><h4 class="title"> 291<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_return_arg_static_function"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_return_arg_static_function" title="Class return_arg static functions">Class 292 <code class="computeroutput"><span class="identifier">return_arg</span></code> static functions</a> 293</h4></div></div></div> 294<pre class="programlisting"><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">postcall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">args</span><span class="special">,</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">result</span><span class="special">);</span></pre> 295<div class="variablelist"> 296<p class="title"><b></b></p> 297<dl class="variablelist"> 298<dt><span class="term">Requires</span></dt> 299<dd><p> 300 <code class="computeroutput"><span class="identifier">PyTuple_Check</span><span class="special">(</span><span class="identifier">args</span><span class="special">)</span> 301 <span class="special">!=</span> <span class="number">0</span></code> 302 and <code class="computeroutput"><span class="identifier">PyTuple_Size</span><span class="special">(</span><span class="identifier">args</span><span class="special">)</span> <span class="special">!=</span> <span class="number">0</span></code> 303 </p></dd> 304<dt><span class="term">Returns</span></dt> 305<dd><p> 306 PyTuple_GetItem(args,arg_pos-1) 307 </p></dd> 308</dl> 309</div> 310</div> 311<div class="section"> 312<div class="titlepage"><div><div><h4 class="title"> 313<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_template_return_self"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.class_template_return_self" title="Class template return_self">Class 314 template <code class="computeroutput"><span class="identifier">return_self</span></code></a> 315</h4></div></div></div> 316<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> 317<span class="special">{</span> 318 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Base</span> <span class="special">=</span> <span class="identifier">default_call_policies</span><span class="special">></span> 319 <span class="keyword">struct</span> <span class="identifier">return_self</span> 320 <span class="special">:</span> <span class="identifier">return_arg</span><span class="special"><</span><span class="number">1</span><span class="special">,</span><span class="identifier">Base</span><span class="special">></span> 321 <span class="special">{};</span> 322<span class="special">}}</span> 323</pre> 324</div> 325<div class="section"> 326<div class="titlepage"><div><div><h4 class="title"> 327<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.example"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_arg_hpp.example" title="Example">Example</a> 328</h4></div></div></div> 329<p> 330 C++ module definition: 331 </p> 332<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="identifier">module</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 333<span class="preprocessor">#include</span> <span class="special"><</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">></span> 334<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="identifier">return_arg</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 335 336<span class="keyword">struct</span> <span class="identifier">Widget</span> 337<span class="special">{</span> 338 <span class="identifier">Widget</span><span class="special">()</span> <span class="special">:</span><span class="identifier">sensitive_</span><span class="special">(</span><span class="keyword">true</span><span class="special">){}</span> 339 <span class="keyword">bool</span> <span class="identifier">get_sensitive</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">sensitive_</span><span class="special">;</span> <span class="special">}</span> 340 <span class="keyword">void</span> <span class="identifier">set_sensitive</span><span class="special">(</span><span class="keyword">bool</span> <span class="identifier">s</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">this</span><span class="special">-></span><span class="identifier">sensitive_</span> <span class="special">=</span> <span class="identifier">s</span><span class="special">;</span> <span class="special">}</span> 341 <span class="keyword">private</span><span class="special">:</span> 342 <span class="keyword">bool</span> <span class="identifier">sensitive_</span><span class="special">;</span> 343<span class="special">};</span> 344 345<span class="keyword">struct</span> <span class="identifier">Label</span> <span class="special">:</span> <span class="identifier">Widget</span> 346<span class="special">{</span> 347 <span class="identifier">Label</span><span class="special">()</span> <span class="special">{}</span> 348 349 <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">get_label</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">label_</span><span class="special">;</span> <span class="special">}</span> 350 <span class="keyword">void</span> <span class="identifier">set_label</span><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="special">&</span><span class="identifier">l</span><span class="special">){</span> <span class="identifier">label_</span> <span class="special">=</span> <span class="identifier">l</span><span class="special">;</span> <span class="special">}</span> 351 352 <span class="keyword">private</span><span class="special">:</span> 353 <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">label_</span><span class="special">;</span> 354<span class="special">};</span> 355 356<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">;</span> 357<span class="identifier">BOOST_PYTHON_MODULE</span><span class="special">(</span><span class="identifier">return_self_ext</span><span class="special">)</span> 358<span class="special">{</span> 359 <span class="identifier">class_</span><span class="special"><</span><span class="identifier">widget</span><span class="special">>(</span><span class="string">"Widget"</span><span class="special">)</span> 360 <span class="special">.</span><span class="identifier">def</span><span class="special">(</span><span class="string">"sensitive"</span><span class="special">,</span> <span class="special">&</span><span class="identifier">Widget</span><span class="special">::</span><span class="identifier">get_sensitive</span><span class="special">)</span> 361 <span class="special">.</span><span class="identifier">def</span><span class="special">(</span><span class="string">"sensitive"</span><span class="special">,</span> <span class="special">&</span><span class="identifier">Widget</span><span class="special">::</span><span class="identifier">set_sensitive</span><span class="special">,</span> <span class="identifier">return_self</span><span class="special"><>())</span> 362 <span class="special">;</span> 363 364 <span class="identifier">class_</span><span class="special"><</span><span class="identifier">Label</span><span class="special">,</span> <span class="identifier">bases</span><span class="special"><</span><span class="identifier">Widget</span><span class="special">></span> <span class="special">>(</span><span class="string">"Label"</span><span class="special">)</span> 365 <span class="special">.</span><span class="identifier">def</span><span class="special">(</span><span class="string">"label"</span><span class="special">,</span> <span class="special">&</span><span class="identifier">Label</span><span class="special">::</span><span class="identifier">get_label</span><span class="special">)</span> 366 <span class="special">.</span><span class="identifier">def</span><span class="special">(</span><span class="string">"label"</span><span class="special">,</span> <span class="special">&</span><span class="identifier">Label</span><span class="special">::</span><span class="identifier">set_label</span><span class="special">,</span> <span class="identifier">return_self</span><span class="special"><>())</span> 367 <span class="special">;</span> 368<span class="special">}</span> 369</pre> 370<p> 371 Python code: 372 </p> 373<pre class="programlisting"><span class="special">>>></span> <span class="identifier">from</span> <span class="identifier">return_self_ext</span> <span class="identifier">import</span> <span class="special">*</span> 374<span class="special">>>></span> <span class="identifier">l1</span> <span class="special">=</span> <span class="identifier">Label</span><span class="special">().</span><span class="identifier">label</span><span class="special">(</span><span class="string">"foo"</span><span class="special">).</span><span class="identifier">sensitive</span><span class="special">(</span><span class="keyword">false</span><span class="special">)</span> 375<span class="special">>>></span> <span class="identifier">l2</span> <span class="special">=</span> <span class="identifier">Label</span><span class="special">().</span><span class="identifier">sensitive</span><span class="special">(</span><span class="keyword">false</span><span class="special">).</span><span class="identifier">label</span><span class="special">(</span><span class="string">"foo"</span><span class="special">)</span> 376</pre> 377</div> 378</div> 379<div class="section"> 380<div class="titlepage"><div><div><h3 class="title"> 381<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref" title="boost/python/return_internal_reference.hpp">boost/python/return_internal_reference.hpp</a> 382</h3></div></div></div> 383<div class="toc"><dl class="toc"> 384<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.introduction">Introduction</a></span></dt> 385<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.class_template_return_internal_r">Class 386 template <code class="computeroutput"><span class="identifier">return_internal_reference</span></code></a></span></dt> 387<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.class_return_internal_reference_">Class 388 <code class="computeroutput"><span class="identifier">return_internal_reference</span></code> 389 static functions</a></span></dt> 390<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.example">Example</a></span></dt> 391</dl></div> 392<div class="section"> 393<div class="titlepage"><div><div><h4 class="title"> 394<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.introduction"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.introduction" title="Introduction">Introduction</a> 395</h4></div></div></div> 396<p> 397 <code class="computeroutput"><span class="identifier">return_internal_reference</span></code> 398 instantiations are models of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> which allow pointers 399 and references to objects held internally by a free or member function 400 argument or from the target of a member function to be returned safely 401 without making a copy of the referent. The default for its first template 402 argument handles the common case where the containing object is the target 403 (<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>) 404 of a wrapped member function. 405 </p> 406</div> 407<div class="section"> 408<div class="titlepage"><div><div><h4 class="title"> 409<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.class_template_return_internal_r"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.class_template_return_internal_r" title="Class template return_internal_reference">Class 410 template <code class="computeroutput"><span class="identifier">return_internal_reference</span></code></a> 411</h4></div></div></div> 412<div class="informaltable"><table class="table"> 413<colgroup> 414<col> 415<col> 416<col> 417<col> 418</colgroup> 419<thead><tr> 420<th> 421 <p> 422 Parameter 423 </p> 424 </th> 425<th> 426 <p> 427 Requirements 428 </p> 429 </th> 430<th> 431 <p> 432 Description 433 </p> 434 </th> 435<th> 436 <p> 437 Default 438 </p> 439 </th> 440</tr></thead> 441<tbody> 442<tr> 443<td> 444 <p> 445 owner_arg 446 </p> 447 </td> 448<td> 449 <p> 450 A positive compile-time constant of type <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>. 451 </p> 452 </td> 453<td> 454 <p> 455 The index of the parameter which contains the object to which 456 the reference or pointer is being returned. If used to wrap 457 a member function, parameter 1 is the target object (<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>). 458 Note that if the target Python object type doesn't support 459 weak references, a Python TypeError exception will be raised 460 when the function being wrapped is called. 461 </p> 462 </td> 463<td> 464 </td> 465</tr> 466<tr> 467<td> 468 <p> 469 Base 470 </p> 471 </td> 472<td> 473 <p> 474 A model of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> 475 </p> 476 </td> 477<td> 478 <p> 479 Used for policy composition. Any <code class="computeroutput"><span class="identifier">result_converter</span></code> 480 it supplies will be overridden by <code class="computeroutput"><span class="identifier">return_internal_reference</span></code>, 481 but its <code class="computeroutput"><span class="identifier">precall</span></code> 482 and <code class="computeroutput"><span class="identifier">postcall</span></code> 483 policies are composed as described here <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a>. 484 </p> 485 </td> 486<td> 487 <p> 488 default_call_policies 489 </p> 490 </td> 491</tr> 492</tbody> 493</table></div> 494<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> 495<span class="special">{</span> 496 <span class="keyword">template</span> <span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">owner_arg</span> <span class="special">=</span> <span class="number">1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span> <span class="special">=</span> <span class="identifier">default_call_policies</span><span class="special">></span> 497 <span class="keyword">struct</span> <span class="identifier">return_internal_reference</span> <span class="special">:</span> <span class="identifier">Base</span> 498 <span class="special">{</span> 499 <span class="keyword">static</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">postcall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*,</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">result</span><span class="special">);</span> 500 <span class="keyword">typedef</span> <span class="identifier">reference_existing_object</span> <span class="identifier">result_converter</span><span class="special">;</span> 501 <span class="special">};</span> 502<span class="special">}}</span> 503</pre> 504</div> 505<div class="section"> 506<div class="titlepage"><div><div><h4 class="title"> 507<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.class_return_internal_reference_"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.class_return_internal_reference_" title="Class return_internal_reference static functions">Class 508 <code class="computeroutput"><span class="identifier">return_internal_reference</span></code> 509 static functions</a> 510</h4></div></div></div> 511<pre class="programlisting"><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">postcall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">args</span><span class="special">,</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">result</span><span class="special">);</span></pre> 512<div class="variablelist"> 513<p class="title"><b></b></p> 514<dl class="variablelist"> 515<dt><span class="term">Requires</span></dt> 516<dd><p> 517 <code class="computeroutput"><span class="identifier">PyTuple_Check</span><span class="special">(</span><span class="identifier">args</span><span class="special">)</span> 518 <span class="special">!=</span> <span class="number">0</span></code> 519 </p></dd> 520<dt><span class="term">Returns</span></dt> 521<dd><p> 522 <a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_st" title="Class with_custodian_and_ward static functions"><code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span><span class="special">::</span><span class="identifier">postcall</span><span class="special">(</span><span class="identifier">args</span><span class="special">,</span> <span class="identifier">result</span><span class="special">)</span></code></a> 523 </p></dd> 524</dl> 525</div> 526</div> 527<div class="section"> 528<div class="titlepage"><div><div><h4 class="title"> 529<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.example"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_internal_ref.example" title="Example">Example</a> 530</h4></div></div></div> 531<p> 532 C++ module definition: 533 </p> 534<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="identifier">module</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 535<span class="preprocessor">#include</span> <span class="special"><</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">></span> 536<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="identifier">return_internal_reference</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 537 538<span class="keyword">class</span> <span class="identifier">Bar</span> 539<span class="special">{</span> 540 <span class="keyword">public</span><span class="special">:</span> 541 <span class="identifier">Bar</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">x</span><span class="special">)</span> <span class="special">:</span> <span class="identifier">x</span><span class="special">(</span><span class="identifier">x</span><span class="special">)</span> <span class="special">{}</span> 542 <span class="keyword">int</span> <span class="identifier">get_x</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">x</span><span class="special">;</span> <span class="special">}</span> 543 <span class="keyword">void</span> <span class="identifier">set_x</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">x</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">this</span><span class="special">-></span><span class="identifier">x</span> <span class="special">=</span> <span class="identifier">x</span><span class="special">;</span> <span class="special">}</span> 544 <span class="keyword">private</span><span class="special">:</span> 545 <span class="keyword">int</span> <span class="identifier">x</span><span class="special">;</span> 546<span class="special">};</span> 547 548<span class="keyword">class</span> <span class="identifier">Foo</span> 549<span class="special">{</span> 550 <span class="keyword">public</span><span class="special">:</span> 551 <span class="identifier">Foo</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">x</span><span class="special">)</span> <span class="special">:</span> <span class="identifier">b</span><span class="special">(</span><span class="identifier">x</span><span class="special">)</span> <span class="special">{}</span> 552 553 <span class="comment">// Returns an internal reference</span> 554 <span class="identifier">Bar</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">get_bar</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">b</span><span class="special">;</span> <span class="special">}</span> 555 556 <span class="keyword">private</span><span class="special">:</span> 557 <span class="identifier">Bar</span> <span class="identifier">b</span><span class="special">;</span> 558<span class="special">};</span> 559 560<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">;</span> 561<span class="identifier">BOOST_PYTHON_MODULE</span><span class="special">(</span><span class="identifier">internal_refs</span><span class="special">)</span> 562<span class="special">{</span> 563 <span class="identifier">class_</span><span class="special"><</span><span class="identifier">Bar</span><span class="special">>(</span><span class="string">"Bar"</span><span class="special">,</span> <span class="identifier">init</span><span class="special"><</span><span class="keyword">int</span><span class="special">>())</span> 564 <span class="special">.</span><span class="identifier">def</span><span class="special">(</span><span class="string">"get_x"</span><span class="special">,</span> <span class="special">&</span><span class="identifier">Bar</span><span class="special">::</span><span class="identifier">get_x</span><span class="special">)</span> 565 <span class="special">.</span><span class="identifier">def</span><span class="special">(</span><span class="string">"set_x"</span><span class="special">,</span> <span class="special">&</span><span class="identifier">Bar</span><span class="special">::</span><span class="identifier">set_x</span><span class="special">)</span> 566 <span class="special">;</span> 567 568 <span class="identifier">class_</span><span class="special"><</span><span class="identifier">Foo</span><span class="special">>(</span><span class="string">"Foo"</span><span class="special">,</span> <span class="identifier">init</span><span class="special"><</span><span class="keyword">int</span><span class="special">>())</span> 569 <span class="special">.</span><span class="identifier">def</span><span class="special">(</span><span class="string">"get_bar"</span><span class="special">,</span> <span class="special">&</span><span class="identifier">Foo</span><span class="special">::</span><span class="identifier">get_bar</span> 570 <span class="special">,</span> <span class="identifier">return_internal_reference</span><span class="special"><>())</span> 571 <span class="special">;</span> 572<span class="special">}</span> 573</pre> 574<p> 575 Python code: 576 </p> 577<pre class="programlisting"><span class="special">>>></span> <span class="identifier">from</span> <span class="identifier">internal_refs</span> <span class="identifier">import</span> <span class="special">*</span> 578<span class="special">>>></span> <span class="identifier">f</span> <span class="special">=</span> <span class="identifier">Foo</span><span class="special">(</span><span class="number">3</span><span class="special">)</span> 579<span class="special">>>></span> <span class="identifier">b1</span> <span class="special">=</span> <span class="identifier">f</span><span class="special">.</span><span class="identifier">get_bar</span><span class="special">()</span> 580<span class="special">>>></span> <span class="identifier">b2</span> <span class="special">=</span> <span class="identifier">f</span><span class="special">.</span><span class="identifier">get_bar</span><span class="special">()</span> 581<span class="special">>>></span> <span class="identifier">b1</span><span class="special">.</span><span class="identifier">get_x</span><span class="special">()</span> 582<span class="number">3</span> 583<span class="special">>>></span> <span class="identifier">b2</span><span class="special">.</span><span class="identifier">get_x</span><span class="special">()</span> 584<span class="number">3</span> 585<span class="special">>>></span> <span class="identifier">b1</span><span class="special">.</span><span class="identifier">set_x</span><span class="special">(</span><span class="number">42</span><span class="special">)</span> 586<span class="special">>>></span> <span class="identifier">b2</span><span class="special">.</span><span class="identifier">get_x</span><span class="special">()</span> 587<span class="number">42</span> 588</pre> 589</div> 590</div> 591<div class="section"> 592<div class="titlepage"><div><div><h3 class="title"> 593<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy" title="boost/python/return_value_policy.hpp">boost/python/return_value_policy.hpp</a> 594</h3></div></div></div> 595<div class="toc"><dl class="toc"> 596<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.introduction">Introduction</a></span></dt> 597<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.class_template_return_value_poli">Class 598 template <code class="computeroutput"><span class="identifier">return_value_policy</span></code></a></span></dt> 599<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.example">Example</a></span></dt> 600</dl></div> 601<div class="section"> 602<div class="titlepage"><div><div><h4 class="title"> 603<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.introduction"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.introduction" title="Introduction">Introduction</a> 604</h4></div></div></div> 605<p> 606 return_value_policy instantiations are simply models of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> which are composed 607 of a <a class="link" href="../concepts/resultconverter.html#concepts.resultconverter.resultconvertergenerator_concept" title="ResultConverterGenerator Concept Requirements"><code class="computeroutput"><span class="identifier">ResultConverterGenerator</span></code></a> and 608 optional <code class="computeroutput"><span class="identifier">Base</span></code> <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a>. 609 </p> 610</div> 611<div class="section"> 612<div class="titlepage"><div><div><h4 class="title"> 613<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.class_template_return_value_poli"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.class_template_return_value_poli" title="Class template return_value_policy">Class 614 template <code class="computeroutput"><span class="identifier">return_value_policy</span></code></a> 615</h4></div></div></div> 616<div class="informaltable"><table class="table"> 617<colgroup> 618<col> 619<col> 620<col> 621</colgroup> 622<thead><tr> 623<th> 624 <p> 625 Parameter 626 </p> 627 </th> 628<th> 629 <p> 630 Requirements 631 </p> 632 </th> 633<th> 634 <p> 635 Default 636 </p> 637 </th> 638</tr></thead> 639<tbody> 640<tr> 641<td> 642 <p> 643 ResultConverterGenerator 644 </p> 645 </td> 646<td> 647 <p> 648 A model of <a class="link" href="../concepts/resultconverter.html#concepts.resultconverter.resultconvertergenerator_concept" title="ResultConverterGenerator Concept Requirements"><code class="computeroutput"><span class="identifier">ResultConverterGenerator</span></code></a> 649 </p> 650 </td> 651<td> 652 </td> 653</tr> 654<tr> 655<td> 656 <p> 657 Base 658 </p> 659 </td> 660<td> 661 <p> 662 A model of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> 663 </p> 664 </td> 665<td> 666 <p> 667 default_call_policies 668 </p> 669 </td> 670</tr> 671</tbody> 672</table></div> 673<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> 674<span class="special">{</span> 675 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">ResultConverterGenerator</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span> <span class="special">=</span> <span class="identifier">default_call_policies</span><span class="special">></span> 676 <span class="keyword">struct</span> <span class="identifier">return_value_policy</span> <span class="special">:</span> <span class="identifier">Base</span> 677 <span class="special">{</span> 678 <span class="keyword">typedef</span> <span class="identifier">ResultConverterGenerator</span> <span class="identifier">result_converter</span><span class="special">;</span> 679 <span class="special">};</span> 680<span class="special">}}</span> 681</pre> 682</div> 683<div class="section"> 684<div class="titlepage"><div><div><h4 class="title"> 685<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.example"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_return_value_policy.example" title="Example">Example</a> 686</h4></div></div></div> 687<p> 688 C++ module definition: 689 </p> 690<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="identifier">module</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 691<span class="preprocessor">#include</span> <span class="special"><</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">></span> 692<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="identifier">copy_const_reference</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 693<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">python</span><span class="special">/</span><span class="identifier">return_value_policy</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 694 695<span class="comment">// classes to wrap</span> 696<span class="keyword">struct</span> <span class="identifier">Bar</span> <span class="special">{</span> <span class="keyword">int</span> <span class="identifier">x</span><span class="special">;</span> <span class="special">}</span> 697 698<span class="keyword">struct</span> <span class="identifier">Foo</span> <span class="special">{</span> 699 <span class="identifier">Foo</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">x</span><span class="special">)</span> <span class="special">:</span> <span class="special">{</span> <span class="identifier">b</span><span class="special">.</span><span class="identifier">x</span> <span class="special">=</span> <span class="identifier">x</span><span class="special">;</span> <span class="special">}</span> 700 <span class="identifier">Bar</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">get_bar</span><span class="special">()</span> <span class="keyword">const</span> <span class="special">{</span> <span class="keyword">return</span> <span class="identifier">b</span><span class="special">;</span> <span class="special">}</span> 701 <span class="keyword">private</span><span class="special">:</span> 702 <span class="identifier">Bar</span> <span class="identifier">b</span><span class="special">;</span> 703<span class="special">};</span> 704 705<span class="comment">// Wrapper code</span> 706<span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">;</span> 707<span class="identifier">BOOST_PYTHON_MODULE</span><span class="special">(</span><span class="identifier">my_module</span><span class="special">)</span> 708<span class="special">{</span> 709 <span class="identifier">class_</span><span class="special"><</span><span class="identifier">Bar</span><span class="special">>(</span><span class="string">"Bar"</span><span class="special">);</span> 710 711 <span class="identifier">class_</span><span class="special"><</span><span class="identifier">Foo</span><span class="special">>(</span><span class="string">"Foo"</span><span class="special">,</span> <span class="identifier">init</span><span class="special"><</span><span class="keyword">int</span><span class="special">>())</span> 712 <span class="special">.</span><span class="identifier">def</span><span class="special">(</span><span class="string">"get_bar"</span><span class="special">,</span> <span class="special">&</span><span class="identifier">Foo</span><span class="special">::</span><span class="identifier">get_bar</span> 713 <span class="special">,</span> <span class="identifier">return_value_policy</span><span class="special"><</span><span class="identifier">copy_const_reference</span><span class="special">>())</span> 714 <span class="special">;</span> 715<span class="special">}</span> 716</pre> 717<p> 718 Python code: 719 </p> 720<pre class="programlisting"><span class="special">>>></span> <span class="identifier">from</span> <span class="identifier">my_module</span> <span class="identifier">import</span> <span class="special">*</span> 721<span class="special">>>></span> <span class="identifier">f</span> <span class="special">=</span> <span class="identifier">Foo</span><span class="special">(</span><span class="number">3</span><span class="special">)</span> <span class="special">#</span> <span class="identifier">create</span> <span class="identifier">a</span> <span class="identifier">Foo</span> <span class="identifier">object</span> 722<span class="special">>>></span> <span class="identifier">b</span> <span class="special">=</span> <span class="identifier">f</span><span class="special">.</span><span class="identifier">get_bar</span><span class="special">()</span> <span class="special">#</span> <span class="identifier">make</span> <span class="identifier">a</span> <span class="identifier">copy</span> <span class="identifier">of</span> <span class="identifier">the</span> <span class="identifier">internal</span> <span class="identifier">Bar</span> <span class="identifier">object</span> 723</pre> 724</div> 725</div> 726<div class="section"> 727<div class="titlepage"><div><div><h3 class="title"> 728<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_" title="boost/python/with_custodian_and_ward.hpp">boost/python/with_custodian_and_ward.hpp</a> 729</h3></div></div></div> 730<div class="toc"><dl class="toc"> 731<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.introduction">Introduction</a></span></dt> 732<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward">Class 733 <code class="computeroutput"><span class="identifier">with_custodian_and_ward</span></code></a></span></dt> 734<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_st">Class 735 <code class="computeroutput"><span class="identifier">with_custodian_and_ward</span></code> 736 static functions</a></span></dt> 737<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_po">Class 738 <code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span></code></a></span></dt> 739<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_p0">Class 740 <code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span></code> 741 static functions</a></span></dt> 742<dt><span class="section"><a href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.example">Example</a></span></dt> 743</dl></div> 744<div class="section"> 745<div class="titlepage"><div><div><h4 class="title"> 746<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.introduction"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.introduction" title="Introduction">Introduction</a> 747</h4></div></div></div> 748<p> 749 This header provides facilities for establishing a lifetime dependency 750 between two of a function's Python argument or result objects. The ward 751 object will not be destroyed until after the custodian as long as the 752 custodian object supports <a href="http://www.python.org/doc/current/lib/module-weakref.html" target="_top">weak 753 references</a> (Boost.Python extension classes all support weak references). 754 If the custodian object does not support weak references and is not 755 <code class="computeroutput"><span class="identifier">None</span></code>, an appropriate 756 exception will be thrown. The two class templates <code class="computeroutput"><span class="identifier">with_custodian_and_ward</span></code> 757 and <code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span></code> 758 differ in the point at which they take effect. 759 </p> 760<p> 761 In order to reduce the chance of inadvertently creating dangling pointers, 762 the default is to do lifetime binding before the underlying C++ object 763 is invoked. However, before invocation the result object is not available, 764 so <code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span></code> 765 is provided to bind lifetimes after invocation. Also, if a C++ exception 766 is thrown after <code class="computeroutput"><span class="identifier">with_custodian_and_ward</span><span class="special"><>::</span><span class="identifier">precall</span></code> 767 but before the underlying C++ object actually stores a pointer, the lifetime 768 of the custodian and ward objects will be artificially bound together, 769 so one might choose <code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span></code> 770 instead, depending on the semantics of the function being wrapped. 771 </p> 772<p> 773 Please note that this is not the appropriate tool to use when wrapping 774 functions which transfer ownership of a raw pointer across the function-call 775 boundary. Please see the FAQ if you want to do that. 776 </p> 777</div> 778<div class="section"> 779<div class="titlepage"><div><div><h4 class="title"> 780<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward" title="Class with_custodian_and_ward">Class 781 <code class="computeroutput"><span class="identifier">with_custodian_and_ward</span></code></a> 782</h4></div></div></div> 783<div class="informaltable"><table class="table"> 784<colgroup> 785<col> 786<col> 787<col> 788<col> 789</colgroup> 790<thead><tr> 791<th> 792 <p> 793 Parameter 794 </p> 795 </th> 796<th> 797 <p> 798 Requirements 799 </p> 800 </th> 801<th> 802 <p> 803 Description 804 </p> 805 </th> 806<th> 807 <p> 808 Default 809 </p> 810 </th> 811</tr></thead> 812<tbody> 813<tr> 814<td> 815 <p> 816 custodian 817 </p> 818 </td> 819<td> 820 <p> 821 A positive compile-time constant of <code class="computeroutput"><span class="identifier">type</span> 822 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>. 823 </p> 824 </td> 825<td> 826 <p> 827 The 1-based index of the parameter which is the dependency 828 in the lifetime relationship to be established. If used to 829 wrap a member function, parameter 1 is the target object (<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>). 830 Note that if the target Python object type doesn't support 831 weak references, a Python TypeError exception will be raised 832 when the C++ object being wrapped is called. 833 </p> 834 </td> 835<td> 836 </td> 837</tr> 838<tr> 839<td> 840 <p> 841 ward 842 </p> 843 </td> 844<td> 845 <p> 846 A positive compile-time constant of type <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>. 847 </p> 848 </td> 849<td> 850 <p> 851 The 1-based index of the parameter which is the dependent in 852 the lifetime relationship to be established. If used to wrap 853 a member function, parameter 1 is the target object (<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>). 854 </p> 855 </td> 856<td> 857 </td> 858</tr> 859<tr> 860<td> 861 <p> 862 Base 863 </p> 864 </td> 865<td> 866 <p> 867 A model of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> 868 </p> 869 </td> 870<td> 871 <p> 872 Used for policy <a class="link" href="../concepts.html#concepts.callpolicies.callpolicies_composition" title="CallPolicies Composition">composition</a>. 873 </p> 874 </td> 875<td> 876 <p> 877 default_call_policies 878 </p> 879 </td> 880</tr> 881</tbody> 882</table></div> 883<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> 884<span class="special">{</span> 885 <span class="keyword">template</span> <span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">custodian</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">ward</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span> <span class="special">=</span> <span class="identifier">default_call_policies</span><span class="special">></span> 886 <span class="keyword">struct</span> <span class="identifier">with_custodian_and_ward</span> <span class="special">:</span> <span class="identifier">Base</span> 887 <span class="special">{</span> 888 <span class="keyword">static</span> <span class="keyword">bool</span> <span class="identifier">precall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">args</span><span class="special">);</span> 889 <span class="special">};</span> 890<span class="special">}}</span></pre> 891</div> 892<div class="section"> 893<div class="titlepage"><div><div><h4 class="title"> 894<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_st"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_st" title="Class with_custodian_and_ward static functions">Class 895 <code class="computeroutput"><span class="identifier">with_custodian_and_ward</span></code> 896 static functions</a> 897</h4></div></div></div> 898<pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">precall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">args</span><span class="special">);</span></pre> 899<div class="variablelist"> 900<p class="title"><b></b></p> 901<dl class="variablelist"> 902<dt><span class="term">Requires</span></dt> 903<dd><p> 904 <code class="computeroutput"><span class="identifier">PyTuple_Check</span><span class="special">(</span><span class="identifier">args</span><span class="special">)</span> 905 <span class="special">!=</span> <span class="number">0</span></code> 906 </p></dd> 907<dt><span class="term">Effects</span></dt> 908<dd><p> 909 Makes the lifetime of the argument indicated by ward dependent 910 on the lifetime of the argument indicated by custodian. 911 </p></dd> 912<dt><span class="term">Returns</span></dt> 913<dd><p> 914 false and PyErr_Occurred() != 0 upon failure, true otherwise. 915 </p></dd> 916</dl> 917</div> 918</div> 919<div class="section"> 920<div class="titlepage"><div><div><h4 class="title"> 921<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_po"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_po" title="Class with_custodian_and_ward_postcall">Class 922 <code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span></code></a> 923</h4></div></div></div> 924<div class="informaltable"><table class="table"> 925<colgroup> 926<col> 927<col> 928<col> 929<col> 930</colgroup> 931<thead><tr> 932<th> 933 <p> 934 Parameter 935 </p> 936 </th> 937<th> 938 <p> 939 Requirements 940 </p> 941 </th> 942<th> 943 <p> 944 Description 945 </p> 946 </th> 947<th> 948 <p> 949 Default 950 </p> 951 </th> 952</tr></thead> 953<tbody> 954<tr> 955<td> 956 <p> 957 custodian 958 </p> 959 </td> 960<td> 961 <p> 962 A positive compile-time constant of type <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>. 963 </p> 964 </td> 965<td> 966 <p> 967 The index of the parameter which is the dependency in the lifetime 968 relationship to be established. Zero indicates the result object; 969 1 indicates the first argument. If used to wrap a member function, 970 parameter 1 is the target object (<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>). Note that if the target 971 Python object type doesn't support weak references, a Python 972 TypeError exception will be raised when the C++ object being 973 wrapped is called. 974 </p> 975 </td> 976<td> 977 </td> 978</tr> 979<tr> 980<td> 981 <p> 982 ward 983 </p> 984 </td> 985<td> 986 <p> 987 A positive compile-time constant of type <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span></code>. 988 </p> 989 </td> 990<td> 991 <p> 992 The index of the parameter which is the dependent in the lifetime 993 relationship to be established. Zero indicates the result object; 994 1 indicates the first argument. If used to wrap a member function, 995 parameter 1 is the target object (<code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>). 996 </p> 997 </td> 998<td> 999 </td> 1000</tr> 1001<tr> 1002<td> 1003 <p> 1004 Base 1005 </p> 1006 </td> 1007<td> 1008 <p> 1009 A model of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies"><code class="computeroutput"><span class="identifier">CallPolicies</span></code></a> 1010 </p> 1011 </td> 1012<td> 1013 <p> 1014 Used for policy <a class="link" href="../concepts.html#concepts.callpolicies.callpolicies_composition" title="CallPolicies Composition">composition</a>. 1015 </p> 1016 </td> 1017<td> 1018 <p> 1019 default_call_policies 1020 </p> 1021 </td> 1022</tr> 1023</tbody> 1024</table></div> 1025<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> 1026<span class="special">{</span> 1027 <span class="keyword">template</span> <span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">custodian</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">ward</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span> <span class="special">=</span> <span class="identifier">default_call_policies</span><span class="special">></span> 1028 <span class="keyword">struct</span> <span class="identifier">with_custodian_and_ward_postcall</span> <span class="special">:</span> <span class="identifier">Base</span> 1029 <span class="special">{</span> 1030 <span class="keyword">static</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">postcall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">args</span><span class="special">,</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">result</span><span class="special">);</span> 1031 <span class="special">};</span> 1032<span class="special">}}</span> 1033</pre> 1034</div> 1035<div class="section"> 1036<div class="titlepage"><div><div><h4 class="title"> 1037<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_p0"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.class_with_custodian_and_ward_p0" title="Class with_custodian_and_ward_postcall static functions">Class 1038 <code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span></code> 1039 static functions</a> 1040</h4></div></div></div> 1041<pre class="programlisting"><span class="identifier">PyObject</span> <span class="special">*</span><span class="identifier">postcall</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">args</span><span class="special">,</span> <span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">result</span><span class="special">);</span></pre> 1042<div class="variablelist"> 1043<p class="title"><b></b></p> 1044<dl class="variablelist"> 1045<dt><span class="term">Requires</span></dt> 1046<dd><p> 1047 <code class="computeroutput"><span class="identifier">PyTuple_Check</span><span class="special">(</span><span class="identifier">args</span><span class="special">)</span> 1048 <span class="special">!=</span> <span class="number">0</span></code>, 1049 <code class="computeroutput"><span class="identifier">result</span> <span class="special">!=</span> 1050 <span class="number">0</span></code> 1051 </p></dd> 1052<dt><span class="term">Effects</span></dt> 1053<dd><p> 1054 Makes the lifetime of the object indicated by ward dependent on 1055 the lifetime of the object indicated by custodian. 1056 </p></dd> 1057<dt><span class="term">Returns</span></dt> 1058<dd><p> 1059 <code class="computeroutput"><span class="number">0</span></code> and <code class="computeroutput"><span class="identifier">PyErr_Occurred</span><span class="special">()</span> 1060 <span class="special">!=</span> <span class="number">0</span></code> 1061 upon failure, <code class="computeroutput"><span class="keyword">true</span></code> 1062 otherwise. 1063 </p></dd> 1064</dl> 1065</div> 1066</div> 1067<div class="section"> 1068<div class="titlepage"><div><div><h4 class="title"> 1069<a name="function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.example"></a><a class="link" href="models_of_callpolicies.html#function_invocation_and_creation.models_of_callpolicies.boost_python_with_custodian_and_.example" title="Example">Example</a> 1070</h4></div></div></div> 1071<p> 1072 The following example shows how <code class="computeroutput"><span class="identifier">with_custodian_and_ward_postcall</span></code> 1073 is used by the library to implement <code class="computeroutput"><span class="identifier">return_internal_reference</span></code> 1074 </p> 1075<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">owner_arg</span> <span class="special">=</span> <span class="number">1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Base</span> <span class="special">=</span> <span class="identifier">default_call_policies</span><span class="special">></span> 1076<span class="keyword">struct</span> <span class="identifier">return_internal_reference</span> 1077 <span class="special">:</span> <span class="identifier">with_custodian_and_ward_postcall</span><span class="special"><</span><span class="number">0</span><span class="special">,</span> <span class="identifier">owner_arg</span><span class="special">,</span> <span class="identifier">Base</span><span class="special">></span> 1078<span class="special">{</span> 1079 <span class="keyword">typedef</span> <span class="identifier">reference_existing_object</span> <span class="identifier">result_converter</span><span class="special">;</span> 1080<span class="special">};</span> 1081</pre> 1082</div> 1083</div> 1084</div> 1085<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 1086<td align="left"></td> 1087<td align="right"><div class="copyright-footer">Copyright © 2002-2005, 2015 David Abrahams, Stefan Seefeld<p> 1088 Distributed under the Boost Software License, Version 1.0. (See accompanying 1089 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> 1090 </p> 1091</div></td> 1092</tr></table> 1093<hr> 1094<div class="spirit-nav"> 1095<a accesskey="p" href="function_documentation.html"><img src="../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../function_invocation_and_creation.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="models_of_resultconverter.html"><img src="../../images/next.png" alt="Next"></a> 1096</div> 1097</body> 1098</html> 1099
