<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Struct template hash</title> <link rel="stylesheet" href="../../../doc/src/boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.78.1"> <link rel="home" href="../index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> <link rel="up" href="../hash/reference.html#header.boost.functional.hash_hpp" title="Header <boost/functional/hash.hpp>"> <link rel="prev" href="../hash/reference.html" title="Reference"> <link rel="next" href="hash_boo_idm45507130924768.html" title="Struct hash<bool>"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../boost.png"></td> <td align="center"><a href="../../../index.html">Home</a></td> <td align="center"><a href="../../../libs/libraries.htm">Libraries</a></td> <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> <td align="center"><a href="../../../more/index.htm">More</a></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="../hash/reference.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../hash/reference.html#header.boost.functional.hash_hpp"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="hash_boo_idm45507130924768.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> </div> <div class="refentry"> <a name="boost.hash"></a><div class="titlepage"></div> <div class="refnamediv"> <h2><span class="refentrytitle">Struct template hash</span></h2> <p>boost::hash — A <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2005/n1836.pdf" target="_top">TR1</a> compliant hash function object.</p> </div> <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../hash/reference.html#header.boost.functional.hash_hpp" title="Header <boost/functional/hash.hpp>">boost/functional/hash.hpp</a>> </span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span> <span class="keyword">struct</span> <a class="link" href="hash.html" title="Struct template hash">hash</a> <span class="special">:</span> <span class="keyword">public</span> std::unary_function<T, std::size_t> <span class="special">{</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <a class="link" href="hash.html#idm45507165886288-bb"><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span></a><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span> <span class="special">}</span><span class="special">;</span></pre></div> <div class="refsect1"> <a name="idm45555348496592"></a><h2>Description</h2> <pre class="literallayout"><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <a name="idm45507165886288-bb"></a><span class="keyword">operator</span><span class="special">(</span><span class="special">)</span><span class="special">(</span><span class="identifier">T</span> <span class="keyword">const</span><span class="special">&</span> val<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre> <div class="variablelist"><table border="0" class="variablelist compact"> <colgroup> <col align="left" valign="top"> <col> </colgroup> <tbody> <tr> <td><p><span class="term">Returns:</span></p></td> <td> <p> </p> <pre class="programlisting"><a class="link" href="../hash/reference.html#boost.hash_val_idm45507095703056">hash_value</a><span class="special">(</span><span class="identifier">val</span><span class="special">)</span></pre> <p> </p> </td> </tr> <tr> <td><p><span class="term">Notes:</span></p></td> <td> <p> The call to <code class="computeroutput"><a class="link" href="../hash/reference.html#boost.hash_val_idm45507095703056">hash_value</a></code> is unqualified, so that custom overloads can be found via argument dependent lookup. </p> <p> This is not defined when the macro <code class="computeroutput">BOOST_HASH_NO_EXTENSIONS</code> is defined. The specializations are still defined, so only the specializations required by TR1 are defined. </p> <p> Forward declared in <code class="computeroutput"><boost/functional/hash_fwd.hpp></code> </p> <p> This hash function is not intended for general use, and isn't guaranteed to be equal during separate runs of a program - so please don't use it for any persistent storage or communication. </p> </td> </tr> <tr> <td><p><span class="term">Throws:</span></p></td> <td><p> Only throws if <code class="computeroutput"><a class="link" href="../hash/reference.html#boost.hash_val_idm45507095703056">hash_value</a>(T)</code> throws. </p></td> </tr> </tbody> </table></div> </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 © 2005-2008 Daniel James<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> <div class="spirit-nav"> <a accesskey="p" href="../hash/reference.html"><img src="../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../hash/reference.html#header.boost.functional.hash_hpp"><img src="../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../index.html"><img src="../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="hash_boo_idm45507130924768.html"><img src="../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>