1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>boost/python/call.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="../function_invocation_and_creation.html" title="Chapter 4. Function Invocation and Creation"> 9<link rel="prev" href="../function_invocation_and_creation.html" title="Chapter 4. Function Invocation and Creation"> 10<link rel="next" href="boost_python_call_method_hpp.html" title="boost/python/call_method.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="../function_invocation_and_creation.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="boost_python_call_method_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="function_invocation_and_creation.boost_python_call_hpp"></a><a class="link" href="boost_python_call_hpp.html" title="boost/python/call.hpp">boost/python/call.hpp</a> 21</h2></div></div></div> 22<div class="toc"><dl class="toc"> 23<dt><span class="section"><a href="boost_python_call_hpp.html#function_invocation_and_creation.boost_python_call_hpp.introduction">Introduction</a></span></dt> 24<dt><span class="section"><a href="boost_python_call_hpp.html#function_invocation_and_creation.boost_python_call_hpp.function_call">Function 25 <code class="computeroutput"><span class="identifier">call</span></code></a></span></dt> 26<dt><span class="section"><a href="boost_python_call_hpp.html#function_invocation_and_creation.boost_python_call_hpp.example">Example</a></span></dt> 27</dl></div> 28<div class="section"> 29<div class="titlepage"><div><div><h3 class="title"> 30<a name="function_invocation_and_creation.boost_python_call_hpp.introduction"></a><a class="link" href="boost_python_call_hpp.html#function_invocation_and_creation.boost_python_call_hpp.introduction" title="Introduction">Introduction</a> 31</h3></div></div></div> 32<pre class="programlisting"><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">call</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> <span class="identifier">defines</span> <span class="identifier">the</span> <span class="identifier">call</span> <span class="identifier">family</span> <span class="identifier">of</span> <span class="identifier">overloaded</span> <span class="identifier">function</span> <span class="identifier">templates</span><span class="special">,</span> <span class="identifier">used</span> <span class="identifier">to</span> <span class="identifier">invoke</span> <span class="identifier">Python</span> <span class="identifier">callable</span> <span class="identifier">objects</span> <span class="identifier">from</span> <span class="identifier">C</span><span class="special">++.</span> 33</pre> 34</div> 35<div class="section"> 36<div class="titlepage"><div><div><h3 class="title"> 37<a name="function_invocation_and_creation.boost_python_call_hpp.function_call"></a><a class="link" href="boost_python_call_hpp.html#function_invocation_and_creation.boost_python_call_hpp.function_call" title="Function call">Function 38 <code class="computeroutput"><span class="identifier">call</span></code></a> 39</h3></div></div></div> 40<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">R</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="special">...</span> <span class="keyword">class</span> <span class="identifier">An</span><span class="special">></span> 41<span class="identifier">R</span> <span class="identifier">call</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">callable</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="special">...</span> <span class="identifier">An</span> <span class="keyword">const</span><span class="special">&)</span> 42</pre> 43<div class="variablelist"> 44<p class="title"><b></b></p> 45<dl class="variablelist"> 46<dt><span class="term">Requires</span></dt> 47<dd><p> 48 R is a pointer type, reference type, or a complete type with an accessible 49 copy constructor 50 </p></dd> 51<dt><span class="term">Effects</span></dt> 52<dd><p> 53 Invokes callable(a1, a2, ...an) in Python, where a1...an are the 54 arguments to call(), converted to Python objects. 55 </p></dd> 56<dt><span class="term">Returns</span></dt> 57<dd><p> 58 The result of the Python call, converted to the C++ type R. 59 </p></dd> 60<dt><span class="term">Rationale</span></dt> 61<dd><p> 62 For a complete semantic description and rationale, see this page. 63 </p></dd> 64</dl> 65</div> 66</div> 67<div class="section"> 68<div class="titlepage"><div><div><h3 class="title"> 69<a name="function_invocation_and_creation.boost_python_call_hpp.example"></a><a class="link" href="boost_python_call_hpp.html#function_invocation_and_creation.boost_python_call_hpp.example" title="Example">Example</a> 70</h3></div></div></div> 71<p> 72 The following C++ function applies a Python callable object to its two 73 arguments and returns the result. If a Python exception is raised or the 74 result can't be converted to a double, an exception is thrown. 75 </p> 76<pre class="programlisting"><span class="keyword">double</span> <span class="identifier">apply2</span><span class="special">(</span><span class="identifier">PyObject</span><span class="special">*</span> <span class="identifier">func</span><span class="special">,</span> <span class="keyword">double</span> <span class="identifier">x</span><span class="special">,</span> <span class="keyword">double</span> <span class="identifier">y</span><span class="special">)</span> 77<span class="special">{</span> 78 <span class="keyword">return</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">python</span><span class="special">::</span><span class="identifier">call</span><span class="special"><</span><span class="keyword">double</span><span class="special">>(</span><span class="identifier">func</span><span class="special">,</span> <span class="identifier">x</span><span class="special">,</span> <span class="identifier">y</span><span class="special">);</span> 79<span class="special">}</span> 80</pre> 81</div> 82</div> 83<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 84<td align="left"></td> 85<td align="right"><div class="copyright-footer">Copyright © 2002-2005, 2015 David Abrahams, Stefan Seefeld<p> 86 Distributed under the Boost Software License, Version 1.0. (See accompanying 87 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> 88 </p> 89</div></td> 90</tr></table> 91<hr> 92<div class="spirit-nav"> 93<a accesskey="p" href="../function_invocation_and_creation.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="boost_python_call_method_hpp.html"><img src="../../images/next.png" alt="Next"></a> 94</div> 95</body> 96</html> 97
