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| <boost/python/return_value_policy.hpp></title> |
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| <h1 align="center"><a href="../index.html">Boost.Python</a></h1> |
| |
| <h2 align="center">Header |
| <boost/python/return_value_policy.hpp></h2> |
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| </tr> |
| </table> |
| <hr> |
| |
| <h2>Contents</h2> |
| |
| <dl class="page-index"> |
| <dt><a href="#introduction">Introduction</a></dt> |
| |
| <dt><a href="#classes">Classes</a></dt> |
| |
| <dd> |
| <dl class="page-index"> |
| <dt><a href="#return_value_policy-spec">Class Template |
| <code>return_value_policy</code></a></dt> |
| |
| <dd> |
| <dl class="page-index"> |
| <dt><a href="#return_value_policy-spec-synopsis">Class Template |
| <code>return_value_policy</code> synopsis</a></dt> |
| </dl> |
| </dd> |
| </dl> |
| </dd> |
| |
| <dt><a href="#examples">Example</a></dt> |
| </dl> |
| <hr> |
| |
| <h2><a name="introduction"></a>Introduction</h2> |
| <code>return_value_policy</code> instantiations are simply models of <a |
| href="CallPolicies.html">CallPolicies</a> which are composed of a <a |
| href= |
| "ResultConverter.html#ResultConverterGenerator-concept">ResultConverterGenerator</a> |
| and optional <code>Base</code> <a href= |
| "CallPolicies.html">CallPolicies</a>. |
| |
| <h2><a name="classes"></a>Classes</h2> |
| |
| <h3><a name="return_value_policy-spec"></a>Class template |
| <code>return_value_policy</code></h3> |
| |
| <table border="1" summary="return_value_policy template parameters"> |
| <caption> |
| <b><code>return_value_policy</code> template parameters</b> |
| </caption> |
| |
| <tr> |
| <th>Parameter</th> |
| |
| <th>Requirements</th> |
| |
| <th>Default</th> |
| </tr> |
| |
| <tr> |
| <td><a href= |
| "ResultConverter.html#ResultConverterGenerator-concept">ResultConverterGenerator</a></td> |
| |
| <td>A model of <a href= |
| "ResultConverter.html#ResultConverterGenerator-concept">ResultConverterGenerator</a>.</td> |
| </tr> |
| |
| <tr> |
| <td><code>Base</code></td> |
| |
| <td>A model of <a href="CallPolicies.html">CallPolicies</a></td> |
| |
| <td><code><a href= |
| "default_call_policies.html#default_call_policies-spec">default_call_policies</a></code></td> |
| </tr> |
| </table> |
| |
| <h4><a name="return_value_policy-spec-synopsis"></a>Class template |
| <code>return_value_policy</code> synopsis</h4> |
| <pre> |
| namespace boost { namespace python |
| { |
| template <class ResultConverterGenerator, class Base = default_call_policies> |
| struct return_value_policy : Base |
| { |
| typedef ResultConverterGenerator result_converter; |
| }; |
| }} |
| </pre> |
| |
| <h2><a name="examples"></a>Example</h2> |
| |
| <h3>C++ Module Definition</h3> |
| <pre> |
| #include <boost/python/module.hpp> |
| #include <boost/python/class.hpp> |
| #include <boost/python/copy_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 const& get_bar() const { 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_const_reference>()) |
| ; |
| } |
| </pre> |
| |
| <h3>Python Code</h3> |
| <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> |
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