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<div><h2 class="title">
<a name="boost_typeindex"></a>Chapter&#160;1.&#160;Boost.TypeIndex 1.0</h2></div>
<div><p class="copyright">Copyright &#169; 2012 Antony Polukhin</p></div>
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        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>)
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<dl>
<dt><span class="section"><a href="index.html#boost_typeindex.motivation">Motivation</a></span></dt>
<dt><span class="section"><a href="boost_typeindex/getting_started.html">Getting started</a></span></dt>
<dt><span class="section"><a href="boost_typeindex/examples.html">Examples</a></span></dt>
<dt><span class="section"><a href="boost_typeindex/reference.html">Reference</a></span></dt>
<dt><span class="section"><a href="boost_typeindex/performance.html">Performance</a></span></dt>
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<div class="section boost_typeindex_motivation">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="boost_typeindex.motivation"></a><a class="link" href="index.html#boost_typeindex.motivation" title="Motivation">Motivation</a>
</h2></div></div></div>
<p>
      Sometimes getting and storing at runtime information about template type is
      required. For such cases usually used a construction like <code class="computeroutput"><span class="special">&amp;</span><span class="keyword">typeid</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span></code> or C++11 class <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">type_index</span></code>.
      And that is the point, where problems strat:
    </p>
<div class="itemizedlist"><ul class="itemizedlist" type="disc">
<li class="listitem">
          <code class="computeroutput"><span class="keyword">typeid</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span></code> and
          <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">type_index</span></code> require Run Time Type Info
          (RTTI)
        </li>
<li class="listitem">
          <code class="computeroutput"><span class="keyword">typeid</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span></code> strips
          const, volatile and references from type
        </li>
<li class="listitem">
          some compilers have bugs and do not correctly compare <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">type_info</span></code>
          across shared libraries
        </li>
<li class="listitem">
          some implementations of <code class="computeroutput"><span class="keyword">typeid</span><span class="special">(</span><span class="identifier">T</span><span class="special">)</span></code>
          do not strip const, volatile and references
        </li>
<li class="listitem">
          only a few STLs have <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">type_index</span></code>
          implementation
        </li>
<li class="listitem">
          no easy way to store type info without stripping const, volatile and references
        </li>
<li class="listitem">
          no nice and portable way to get human readable type name
        </li>
</ul></div>
<p>
      Boost.TypeIndex was designed to work around those issues.
    </p>
</div>
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<td align="left"><p><small>Last revised: June 03, 2012 at 10:43:14 GMT</small></p></td>
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