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- <div class="titlepage"><div><div><h2 class="title" style="clear: both">
- <a name="function_invocation_and_creation.boost_python_make_function_hpp"></a><a class="link" href="boost_python_make_function_hpp.html" title="boost/python/make_function.hpp">boost/python/make_function.hpp</a>
- </h2></div></div></div>
- <div class="toc"><dl class="toc">
- <dt><span class="section"><a href="boost_python_make_function_hpp.html#function_invocation_and_creation.boost_python_make_function_hpp.introduction">Introduction</a></span></dt>
- <dt><span class="section"><a href="boost_python_make_function_hpp.html#function_invocation_and_creation.boost_python_make_function_hpp.functions">Functions</a></span></dt>
- <dt><span class="section"><a href="boost_python_make_function_hpp.html#function_invocation_and_creation.boost_python_make_function_hpp.example">Example</a></span></dt>
- </dl></div>
- <div class="section">
- <div class="titlepage"><div><div><h3 class="title">
- <a name="function_invocation_and_creation.boost_python_make_function_hpp.introduction"></a><a class="link" href="boost_python_make_function_hpp.html#function_invocation_and_creation.boost_python_make_function_hpp.introduction" title="Introduction">Introduction</a>
- </h3></div></div></div>
- <p>
- make_function() and make_constructor() are the functions used internally
- by def() and class_<>::def() to produce Python callable objects which
- wrap C++ functions and member functions.
- </p>
- </div>
- <div class="section">
- <div class="titlepage"><div><div><h3 class="title">
- <a name="function_invocation_and_creation.boost_python_make_function_hpp.functions"></a><a class="link" href="boost_python_make_function_hpp.html#function_invocation_and_creation.boost_python_make_function_hpp.functions" title="Functions">Functions</a>
- </h3></div></div></div>
- <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>
- <span class="identifier">object</span> <span class="identifier">make_function</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">)</span>
- <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Policies</span><span class="special">></span>
- <span class="identifier">object</span> <span class="identifier">make_function</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">Policies</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">policies</span><span class="special">)</span>
- <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Policies</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">KeywordsOrSignature</span><span class="special">></span>
- <span class="identifier">object</span> <span class="identifier">make_function</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">Policies</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">policies</span><span class="special">,</span> <span class="identifier">KeywordsOrSignature</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">ks</span><span class="special">)</span>
- <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Policies</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Keywords</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Signature</span><span class="special">></span>
- <span class="identifier">object</span> <span class="identifier">make_function</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">Policies</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">policies</span><span class="special">,</span> <span class="identifier">Keywords</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">kw</span><span class="special">,</span> <span class="identifier">Signature</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">sig</span><span class="special">)</span>
- </pre>
- <div class="variablelist">
- <p class="title"><b></b></p>
- <dl class="variablelist">
- <dt><span class="term">Requires</span></dt>
- <dd><p>
- F is a function pointer or member function pointer type. If policies
- are supplied, it must be a model of CallPolicies. If kewords are
- supplied, it must be the result of a keyword-expression specifying
- no more arguments than the arity of f.
- </p></dd>
- <dt><span class="term">Effects</span></dt>
- <dd>
- <p>
- Creates a Python callable object which, when called from Python,
- converts its arguments to C++ and calls f. If F is a pointer-to-member-function
- type, the target object of the function call (*this) will be taken
- from the first Python argument, and subsequent Python arguments will
- be used as the arguments to f.
- </p>
- <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
- <li class="listitem">
- If policies are supplied, it will be applied to the function
- as described here.
- </li>
- <li class="listitem">
- If keywords are supplied, the keywords will be applied in order
- to the final arguments of the resulting function.
- </li>
- <li class="listitem">
- If Signature is supplied, it should be an instance of an MPL
- front-extensible sequence representing the function's return
- type followed by its argument types. Pass a Signature when wrapping
- function object types whose signatures can't be deduced, or when
- you wish to override the types which will be passed to the wrapped
- function.
- </li>
- </ul></div>
- </dd>
- <dt><span class="term">Returns</span></dt>
- <dd><p>
- An instance of object which holds the new Python callable object.
- </p></dd>
- <dt><span class="term">Caveats</span></dt>
- <dd><p>
- An argument of pointer type may be 0 if None is passed from Python.
- An argument type which is a constant reference may refer to a temporary
- which was created from the Python object for just the duration of
- the call to the wrapped function, for example a std::vector conjured
- up by the conversion process from a Python list. Use a non-const
- reference argument when a persistent lvalue is required.
- </p></dd>
- </dl>
- </div>
- <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>
- <span class="identifier">object</span> <span class="identifier">make_constructor</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">)</span>
- <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Policies</span><span class="special">></span>
- <span class="identifier">object</span> <span class="identifier">make_constructor</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">Policies</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">policies</span><span class="special">)</span>
- <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Policies</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">KeywordsOrSignature</span><span class="special">></span>
- <span class="identifier">object</span> <span class="identifier">make_constructor</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">Policies</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">policies</span><span class="special">,</span> <span class="identifier">KeywordsOrSignature</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">ks</span><span class="special">)</span>
- <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">F</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Policies</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Keywords</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Signature</span><span class="special">></span>
- <span class="identifier">object</span> <span class="identifier">make_constructor</span><span class="special">(</span><span class="identifier">F</span> <span class="identifier">f</span><span class="special">,</span> <span class="identifier">Policies</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">policies</span><span class="special">,</span> <span class="identifier">Keywords</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">kw</span><span class="special">,</span> <span class="identifier">Signature</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">sig</span><span class="special">)</span>
- </pre>
- <div class="variablelist">
- <p class="title"><b></b></p>
- <dl class="variablelist">
- <dt><span class="term">Requires</span></dt>
- <dd><p>
- F is a function pointer type. If policies are supplied, it must be
- a model of CallPolicies. If kewords are supplied, it must be the
- result of a keyword-expression specifying no more arguments than
- the arity of f.
- </p></dd>
- <dt><span class="term">Effects</span></dt>
- <dd><p>
- Creates a Python callable object which, when called from Python,
- converts its arguments to C++ and calls f.
- </p></dd>
- <dt><span class="term">Returns</span></dt>
- <dd><p>
- An instance of object which holds the new Python callable object.
- </p></dd>
- </dl>
- </div>
- </div>
- <div class="section">
- <div class="titlepage"><div><div><h3 class="title">
- <a name="function_invocation_and_creation.boost_python_make_function_hpp.example"></a><a class="link" href="boost_python_make_function_hpp.html#function_invocation_and_creation.boost_python_make_function_hpp.example" title="Example">Example</a>
- </h3></div></div></div>
- <p>
- C++ function exposed below returns a callable object wrapping one of two
- functions.
- </p>
- <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">make_function</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span>
- <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>
- <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="special">{</span> <span class="keyword">return</span> <span class="string">"foo"</span><span class="special">;</span> <span class="special">}</span>
- <span class="keyword">char</span> <span class="keyword">const</span><span class="special">*</span> <span class="identifier">bar</span><span class="special">()</span> <span class="special">{</span> <span class="keyword">return</span> <span class="string">"bar"</span><span class="special">;</span> <span class="special">}</span>
- <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>
- <span class="identifier">object</span> <span class="identifier">choose_function</span><span class="special">(</span><span class="keyword">bool</span> <span class="identifier">selector</span><span class="special">)</span>
- <span class="special">{</span>
- <span class="keyword">if</span> <span class="special">(</span><span class="identifier">selector</span><span class="special">)</span>
- <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">make_function</span><span class="special">(</span><span class="identifier">foo</span><span class="special">);</span>
- <span class="keyword">else</span>
- <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">make_function</span><span class="special">(</span><span class="identifier">bar</span><span class="special">);</span>
- <span class="special">}</span>
- <span class="identifier">BOOST_PYTHON_MODULE</span><span class="special">(</span><span class="identifier">make_function_test</span><span class="special">)</span>
- <span class="special">{</span>
- <span class="identifier">def</span><span class="special">(</span><span class="string">"choose_function"</span><span class="special">,</span> <span class="identifier">choose_function</span><span class="special">);</span>
- <span class="special">}</span>
- </pre>
- <p>
- It can be used this way in Python:
- </p>
- <pre class="programlisting"><span class="special">>>></span> <span class="identifier">from</span> <span class="identifier">make_function_test</span> <span class="identifier">import</span> <span class="special">*</span>
- <span class="special">>>></span> <span class="identifier">f</span> <span class="special">=</span> <span class="identifier">choose_function</span><span class="special">(</span><span class="number">1</span><span class="special">)</span>
- <span class="special">>>></span> <span class="identifier">g</span> <span class="special">=</span> <span class="identifier">choose_function</span><span class="special">(</span><span class="number">0</span><span class="special">)</span>
- <span class="special">>>></span> <span class="identifier">f</span><span class="special">()</span>
- <span class="char">'foo'</span>
- <span class="special">>>></span> <span class="identifier">g</span><span class="special">()</span>
- <span class="char">'bar'</span>
- </pre>
- </div>
- </div>
- <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
- <td align="left"></td>
- <td align="right"><div class="copyright-footer">Copyright © 2002-2005, 2015 David Abrahams, Stefan Seefeld<p>
- Distributed under the Boost Software License, Version 1.0. (See accompanying
- 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>
- </p>
- </div></td>
- </tr></table>
- <hr>
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