1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>boost/python/def.hpp</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="../high_level_components.html" title="Chapter 2. High Level Components"> 9<link rel="prev" href="../high_level_components.html" title="Chapter 2. High Level Components"> 10<link rel="next" href="boost_python_def_visitor_hpp.html" title="boost/python/def_visitor.hpp"> 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="../high_level_components.html"><img src="../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../high_level_components.html"><img src="../../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../images/home.png" alt="Home"></a><a accesskey="n" href="boost_python_def_visitor_hpp.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="high_level_components.boost_python_def_hpp"></a><a class="link" href="boost_python_def_hpp.html" title="boost/python/def.hpp">boost/python/def.hpp</a> 21</h2></div></div></div> 22<div class="toc"><dl class="toc"> 23<dt><span class="section"><a href="boost_python_def_hpp.html#high_level_components.boost_python_def_hpp.introduction">Introduction</a></span></dt> 24<dt><span class="section"><a href="boost_python_def_hpp.html#high_level_components.boost_python_def_hpp.functions">Functions</a></span></dt> 25<dt><span class="section"><a href="boost_python_def_hpp.html#high_level_components.boost_python_def_hpp.example">Example</a></span></dt> 26</dl></div> 27<div class="section"> 28<div class="titlepage"><div><div><h3 class="title"> 29<a name="high_level_components.boost_python_def_hpp.introduction"></a><a class="link" href="boost_python_def_hpp.html#high_level_components.boost_python_def_hpp.introduction" title="Introduction">Introduction</a> 30</h3></div></div></div> 31<p> 32 <code class="computeroutput"><span class="identifier">def</span><span class="special">()</span></code> 33 is the function which can be used to expose C++ functions and callable 34 objects as Python functions in the <a class="link" href="boost_python_scope_hpp.html#high_level_components.boost_python_scope_hpp.introduction" title="Introduction">current 35 scope</a>. 36 </p> 37</div> 38<div class="section"> 39<div class="titlepage"><div><div><h3 class="title"> 40<a name="high_level_components.boost_python_def_hpp.functions"></a><a class="link" href="boost_python_def_hpp.html#high_level_components.boost_python_def_hpp.functions" title="Functions">Functions</a> 41</h3></div></div></div> 42<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">></span> 43<span class="keyword">void</span> <span class="identifier">def</span><span class="special">(</span><span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">name</span><span class="special">,</span> <span class="identifier">F</span> <span class="identifier">f</span><span class="special">);</span> 44 45<span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">A1</span><span class="special">></span> 46<span class="keyword">void</span> <span class="identifier">def</span><span class="special">(</span><span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">name</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">A1</span> <span class="keyword">const</span><span class="special">&);</span> 47 48<span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">A1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">A2</span><span class="special">></span> 49<span class="keyword">void</span> <span class="identifier">def</span><span class="special">(</span><span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">name</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">A1</span> <span class="keyword">const</span><span class="special">&,</span> <span class="identifier">A2</span> <span class="keyword">const</span><span class="special">&);</span> 50 51<span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">Fn</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">A1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">A2</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">A3</span><span class="special">></span> 52<span class="keyword">void</span> <span class="identifier">def</span><span class="special">(</span><span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">name</span><span class="special">,</span> <span class="identifier">Fn</span> <span class="identifier">fn</span><span class="special">,</span> <span class="identifier">A1</span> <span class="keyword">const</span><span class="special">&,</span> <span class="identifier">A2</span> <span class="keyword">const</span><span class="special">&,</span> <span class="identifier">A3</span> <span class="keyword">const</span><span class="special">&);</span> 53</pre> 54<div class="variablelist"> 55<p class="title"><b></b></p> 56<dl class="variablelist"> 57<dt><span class="term">Requires</span></dt> 58<dd> 59<p> 60 name is an <a class="link" href="../glossary.html#ntbs">ntbs</a> which conforms to Python's 61 <a href="http://www.python.org/doc/current/ref/identifiers.html" target="_top">identifier 62 naming rules</a>. 63 </p> 64<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 65<li class="listitem"> 66 If <code class="computeroutput"><span class="identifier">Fn</span></code> is [derived 67 from] <a class="link" href="../object_wrappers/boost_python_object_hpp.html#object_wrappers.boost_python_object_hpp.class_object" title="Class object">object</a>, 68 it will be added to the <a class="link" href="boost_python_scope_hpp.html#high_level_components.boost_python_scope_hpp.introduction" title="Introduction">current 69 scope</a> as a single overload. To be useful, <code class="computeroutput"><span class="identifier">fn</span></code> should be <a href="http://www.python.org/doc/current/lib/built-in-funcs.html#l2h-6" target="_top">callable</a>. 70 </li> 71<li class="listitem"> 72<p class="simpara"> 73 If <code class="computeroutput"><span class="identifier">a1</span></code> is the 74 result of an <a class="link" href="../function_invocation_and_creation/boost_python_overloads_hpp.html#function_invocation_and_creation.boost_python_overloads_hpp.introduction.overload_dispatch_expressions" title="overload-dispatch-expressions">overload-dispatch-expression</a>, 75 only the second form is allowed and <code class="computeroutput"><span class="identifier">fn</span></code> 76 must be a pointer to function or pointer to member function whose 77 <a class="link" href="../glossary.html#arity">arity</a> is the same as A1's <a class="link" href="../function_invocation_and_creation/boost_python_overloads_hpp.html#function_invocation_and_creation.boost_python_overloads_hpp.introduction.overload_dispatch_expressions" title="overload-dispatch-expressions">maximum 78 arity</a>. 79 </p> 80<p class="simpara"> 81 <span class="bold"><strong>Effects:</strong></span> For each prefix <code class="computeroutput"><span class="identifier">P</span></code> of <code class="computeroutput"><span class="identifier">Fn</span></code>'s 82 sequence of argument types, beginning with the one whose length 83 is <code class="computeroutput"><span class="identifier">A1</span></code>'s <a class="link" href="../function_invocation_and_creation/boost_python_overloads_hpp.html#function_invocation_and_creation.boost_python_overloads_hpp.introduction.overload_dispatch_expressions" title="overload-dispatch-expressions">minimum 84 arity</a>, adds a <code class="computeroutput"><span class="identifier">name</span><span class="special">(...)</span></code> function overload to the 85 <a class="link" href="boost_python_scope_hpp.html#high_level_components.boost_python_scope_hpp.introduction" title="Introduction">current 86 scope</a>. Each overload generated invokes a1's call-expression 87 with P, using a copy of a1's call policies. If the longest valid 88 prefix of A1 contains N types and a1 holds M keywords, an initial 89 sequence of the keywords are used for all but the first N - M 90 arguments of each overload. 91 </p> 92</li> 93<li class="listitem"> 94<p class="simpara"> 95 Otherwise, fn must be a non-null function or member function 96 pointer, and a single function overload built around fn is added 97 to the current scope. If any of a1-a3 are supplied, they may 98 be selected in any order from the table below. 99 </p> 100<div class="informaltable"><table class="table"> 101<colgroup> 102<col> 103<col> 104<col> 105</colgroup> 106<thead><tr> 107<th> 108 <p> 109 Mnemonic Name 110 </p> 111 </th> 112<th> 113 <p> 114 Requirements/Type properties 115 </p> 116 </th> 117<th> 118 <p> 119 Effects 120 </p> 121 </th> 122</tr></thead> 123<tbody> 124<tr> 125<td> 126 <p> 127 docstring 128 </p> 129 </td> 130<td> 131 <p> 132 Any <a class="link" href="../glossary.html#ntbs">ntbs</a> 133 </p> 134 </td> 135<td> 136 <p> 137 Value will be bound to the <code class="computeroutput"><span class="identifier">__doc__</span></code> 138 attribute of the resulting method overload. 139 </p> 140 </td> 141</tr> 142<tr> 143<td> 144 <p> 145 policies 146 </p> 147 </td> 148<td> 149 <p> 150 A model of <a class="link" href="../concepts.html#concepts.callpolicies" title="CallPolicies">CallPolicies</a> 151 </p> 152 </td> 153<td> 154 <p> 155 A copy will be used as the call policies of the resulting 156 method overload. 157 </p> 158 </td> 159</tr> 160<tr> 161<td> 162 <p> 163 keywords 164 </p> 165 </td> 166<td> 167 <p> 168 The result of a <a class="link" href="../function_invocation_and_creation.html#function_invocation_and_creation.boost_python_args_hpp.introduction.keyword_expressions" title="keyword-expressions">keyword-expression</a> 169 specifying no more arguments than the <a class="link" href="../glossary.html#arity">arity</a> 170 of <code class="computeroutput"><span class="identifier">fn</span></code>. 171 </p> 172 </td> 173<td> 174 <p> 175 A copy will be used as the call policies of the resulting 176 method overload. 177 </p> 178 </td> 179</tr> 180</tbody> 181</table></div> 182</li> 183</ul></div> 184</dd> 185</dl> 186</div> 187</div> 188<div class="section"> 189<div class="titlepage"><div><div><h3 class="title"> 190<a name="high_level_components.boost_python_def_hpp.example"></a><a class="link" href="boost_python_def_hpp.html#high_level_components.boost_python_def_hpp.example" title="Example">Example</a> 191</h3></div></div></div> 192<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">def</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 193<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> 194<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">args</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 195 196<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> 197 198<span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span> <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="keyword">int</span> <span class="identifier">y</span><span class="special">)</span> <span class="special">{</span> <span class="keyword">return</span> <span class="string">"foo"</span><span class="special">;</span> <span class="special">}</span> 199 200<span class="identifier">BOOST_PYTHON_MODULE</span><span class="special">(</span><span class="identifier">def_test</span><span class="special">)</span> 201<span class="special">{</span> 202 <span class="identifier">def</span><span class="special">(</span><span class="string">"foo"</span><span class="special">,</span> <span class="identifier">foo</span><span class="special">,</span> <span class="identifier">args</span><span class="special">(</span><span class="string">"x"</span><span class="special">,</span> <span class="string">"y"</span><span class="special">),</span> <span class="string">"foo's docstring"</span><span class="special">);</span> 203<span class="special">}</span> 204</pre> 205</div> 206</div> 207<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 208<td align="left"></td> 209<td align="right"><div class="copyright-footer">Copyright © 2002-2005, 2015 David Abrahams, Stefan Seefeld<p> 210 Distributed under the Boost Software License, Version 1.0. (See accompanying 211 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> 212 </p> 213</div></td> 214</tr></table> 215<hr> 216<div class="spirit-nav"> 217<a accesskey="p" href="../high_level_components.html"><img src="../../images/prev.png" alt="Prev"></a><a accesskey="u" href="../high_level_components.html"><img src="../../images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../images/home.png" alt="Home"></a><a accesskey="n" href="boost_python_def_visitor_hpp.html"><img src="../../images/next.png" alt="Next"></a> 218</div> 219</body> 220</html> 221
