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| <h1 align="center"><a href="../index.html">Boost.Python</a></h1> |
| |
| <h2 align="center">Header |
| <boost/python/return_by_value.hpp></h2> |
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| |
| <h2>Contents</h2> |
| |
| <dl class="page-index"> |
| <dt><a href="#classes">Classes</a></dt> |
| |
| <dd> |
| <dl class="page-index"> |
| <dt><a href="#return_by_value-spec">Class |
| <code>return_by_value</code></a></dt> |
| |
| <dd> |
| <dl class="page-index"> |
| <dt><a href="#return_by_value-spec-synopsis">Class |
| <code>return_by_value</code> synopsis</a></dt> |
| |
| <dt><a href="#return_by_value-spec-metafunctions">Class |
| <code>return_by_value</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="return_by_value-spec"></a>Class |
| <code>return_by_value</code></h3> |
| |
| <p><code>return_by_value</code> is a model of <a href= |
| "ResultConverter.html#ResultConverterGenerator-concept">ResultConverterGenerator</a> |
| which can be used to wrap C++ functions returning any reference or value |
| type such that the return value is copied into a new Python object.</p> |
| |
| <h4><a name="return_by_value-spec-synopsis"></a>Class |
| <code>return_by_value</code> synopsis</h4> |
| <pre> |
| namespace boost { namespace python |
| { |
| struct return_by_value |
| { |
| template <class T> struct apply; |
| }; |
| }} |
| </pre> |
| |
| <h4><a name="return_by_value-spec-metafunctions"></a>Class |
| <code>return_by_value</code> metafunctions</h4> |
| <pre> |
| template <class T> struct apply |
| </pre> |
| |
| <dl class="metafunction-semantics"> |
| <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> |
| |
| <h3>C++ Module Definition</h3> |
| <pre> |
| #include <boost/python/module.hpp> |
| #include <boost/python/class.hpp> |
| #include <boost/python/return_by_value.hpp> |
| #include <boost/python/return_value_policy.hpp> |
| |
| // classes to wrap |
| struct Bar { }; |
| |
| Bar global_bar; |
| |
| // functions to wrap: |
| Bar b1(); |
| Bar& b2(); |
| Bar const& b3(); |
| |
| // Wrapper code |
| using namespace boost::python; |
| template <class R> |
| void def_void_function(char const* name, R (*f)()) |
| { |
| def(name, f, return_value_policy<return_by_value>()); |
| } |
| |
| BOOST_PYTHON_MODULE(my_module) |
| { |
| class_<Bar>("Bar"); |
| def_void_function("b1", b1); |
| def_void_function("b2", b2); |
| def_void_function("b3", b3); |
| } |
| </pre> |
| |
| <h3>Python Code</h3> |
| <pre> |
| >>> from my_module import * |
| >>> b = b1() # each of these calls |
| >>> b = b2() # creates a brand |
| >>> b = b3() # new 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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