45 lines
1.3 KiB
HTML
Executable file
45 lines
1.3 KiB
HTML
Executable file
<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
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<title>Boost Function Object Adapter Library</title>
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</head>
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<body>
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<h1>Identity</h1>
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<p>The header <a href="../../boost/functional/identity.hpp">
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<boost/functional/identity.hpp></a> provides the function object
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<code>boost::identity</code> whose <code>operator()</code> returns its
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argument. It is an implementation of C++20's <code>std::identity</code>
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that supports C++03 and above.</p>
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<h2>Example</h2>
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<p>It is commonly used as the default projection in constrained algorithms.</p>
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<pre>
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<code>template<class Range, class Projection = boost::identity>
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void print(Range&& range, Projection projection = {});</code>
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</pre>
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<h2>Reference</h2>
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<pre>
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<code>namespace boost {
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struct identity {
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using is_transparent = <em>unspecified</em>;
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template<class T>
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T&& operator()(T&& value) const noexcept;
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};
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} // boost</code>
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</pre>
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<h3>Operators</h3>
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<dl>
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<dt><code>template<class T>
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T&& operator()(T&& value) const noexcept;</code></dt>
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<dd>Returns <code>std::forward<T>(value)</code></dd>
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</dl>
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<hr>
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<p>Copyright 2021 Glen Joseph Fernandes.</p>
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<p>Distributed under the
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<a href="http://www.boost.org/LICENSE_1_0.txt">Boost Software License,
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Version 1.0</a>.</p>
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</body>
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</html>
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