<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <!-- Copyright David Abrahams 2006. Distributed under the Boost --> <!-- Software License, Version 1.0. (See accompanying --> <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) --> <html> <head> <meta name="generator" content= "HTML Tidy for Windows (vers 1st August 2002), see www.w3.org"> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <link rel="stylesheet" type="text/css" href="../boost.css"> <title>Boost.Python - <boost/python/copy_non_const_reference.hpp></title> </head> <body> <table border="0" cellpadding="7" cellspacing="0" width="100%" summary= "header"> <tr> <td valign="top" width="300"> <h3><a href="../../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../../boost.png" border="0"></a></h3> </td> <td valign="top"> <h1 align="center"><a href="../index.html">Boost.Python</a></h1> <h2 align="center">Header <boost/python/copy_non_const_reference.hpp></h2> </td> </tr> </table> <hr> <h2>Contents</h2> <dl class="page-index"> <dt><a href="#classes">Classes</a></dt> <dd> <dl class="page-index"> <dt><a href="#copy_non_const_reference-spec">Class <code>copy_non_const_reference</code></a></dt> <dd> <dl class="page-index"> <dt><a href="#copy_non_const_reference-spec-synopsis">Class <code>copy_non_const_reference</code> synopsis</a></dt> <dt><a href= "#copy_non_const_reference-spec-metafunctions">Class <code>copy_non_const_reference</code> metafunctions</a></dt> </dl> </dd> </dl> </dd> <dt><a href="#examples">Example</a></dt> </dl> <hr> <h2><a name="classes"></a>Classes</h2> <h3><a name="copy_non_const_reference-spec"></a>Class <code>copy_non_const_reference</code></h3> <p><code>copy_non_const_reference</code> is a model of <a href= "ResultConverter.html#ResultConverterGenerator-concept">ResultConverterGenerator</a> which can be used to wrap C++ functions returning a reference-to-non-const type such that the referenced value is copied into a new Python object.</p> <h4><a name="copy_non_const_reference-spec-synopsis"></a>Class <code>copy_non_const_reference</code> synopsis</h4> <pre> namespace boost { namespace python { struct copy_non_const_reference { template <class T> struct apply; }; }} </pre> <h4><a name="copy_non_const_reference-spec-metafunctions"></a>Class <code>copy_non_const_reference</code> metafunctions</h4> <pre> template <class T> struct apply </pre> <dl class="metafunction-semantics"> <dt><b>Requires:</b> <code>T</code> is <code>U&</code> for some non-const <code>U</code>.</dt> <dt><b>Returns:</b> <code>typedef <a href= "to_python_value.html#to_python_value-spec">to_python_value</a><T> type;</code></dt> </dl> <h2><a name="examples"></a>Example</h2> <p>C++ code:</p> <pre> #include <boost/python/module.hpp> #include <boost/python/class.hpp> #include <boost/python/copy_non_const_reference.hpp> #include <boost/python/return_value_policy.hpp> // classes to wrap struct Bar { int x; } struct Foo { Foo(int x) : { b.x = x; } Bar& get_bar() { return b; } private: Bar b; }; // Wrapper code using namespace boost::python; BOOST_PYTHON_MODULE(my_module) { class_<Bar>("Bar"); class_<Foo>("Foo", init<int>()) .def("get_bar", &Foo::get_bar , return_value_policy<copy_non_const_reference>()) ; } </pre> Python Code: <pre> >>> from my_module import * >>> f = Foo(3) # create a Foo object >>> b = f.get_bar() # make a copy of the internal Bar object </pre> <p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan --> 13 November, 2002 <!--webbot bot="Timestamp" endspan i-checksum="39359" --> </p> <p><i>© Copyright <a href= "http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a> 2002.</i></p> </body> </html>