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<h1>Boost Exception</h1>
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<!-- Copyright (c) 2006-2009 Emil Dotchevski and Reverge Studios, Inc. -->
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<div class="RenoIncludeDIV"><div class="RenoAutoDIV"><h3>enable_current_exception</h3>
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<div class="RenoIncludeDIV"><p><span class="RenoEscape">&#35;<!--<wiki>`&#35;</wiki>--></span>include &lt;<span class="RenoLink"><a href="boost_exception_enable_current_exception_hpp.html">boost/exception/enable_current_exception.hpp</a></span>&gt;</p>
<pre>namespace
boost
    {
<span class="RenoIncludeSPAN">    template &lt;class T&gt;
    ---unspecified--- <span class="RenoLink">enable_current_exception</span>( T const &amp; e );</span>
    }</pre>
</div><h4>Requirements:</h4>
<div><ul><li> T must be a class with an accessible no-throw copy constructor.</li>
<li> If T has any virtual base types, those types must have an accessible default constructor.</li>
</ul></div>
<h4>Returns:</h4>
<p>An object of <i>unspecified</i> type which derives publicly from T. That is, the returned object can be intercepted by a catch(T &amp;).</p>
<h4>Description:</h4>
<p>This function is designed to be used directly in a throw-expression to enable the <span class="RenoLink"><a href="exception_ptr.html">exception_ptr</a></span> support in Boost Exception. For example:</p>
<pre>class
my_exception:
    public std::exception
    {
    };

....
throw boost::<span class="RenoLink">enable_current_exception</span>(my_exception());</pre>
<p>Unless <span class="RenoLink">enable_current_exception</span> is called at the time an exception object is used in a throw-expression, an attempt to copy it using <span class="RenoLink"><a href="current_exception.html">current_exception</a></span> may return an <span class="RenoLink"><a href="exception_ptr.html">exception_ptr</a></span> which refers to an instance of <span class="RenoLink"><a href="unknown_exception.html">unknown_exception</a></span>. See <span class="RenoLink"><a href="current_exception.html">current_exception</a></span> for details.</p>
<h4>Note:</h4>
<p>Instead of using the throw keyword directly, it is preferable to call boost::<span class="RenoLink"><a href="throw_exception.html">throw_exception</a></span>. This is guaranteed to throw an exception that derives from boost::<span class="RenoLink"><a href="exception.html">exception</a></span> and supports the <span class="RenoLink"><a href="exception_ptr.html">exception_ptr</a></span> functionality.</p>
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See also: <span class="RenoPageList"><a href="boost-exception.html">Boost Exception</a>&nbsp;| <a href="boost_exception_enable_current_exception_hpp.html">boost/exception/enable_current_exception.hpp</a>&nbsp;| <a href="configuration_macros.html">Configuration Macros</a>&nbsp;| <a href="copy_exception.html">copy_exception</a>&nbsp;| <a href="current_exception.html">current_exception</a>&nbsp;| <a href="tutorial_exception_ptr.html">Transporting of Exceptions Between Threads</a></span>
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<!-- Copyright (c) 2006-2009 Emil Dotchevski and Reverge Studios, Inc. -->
<!-- Distributed under the Boost Software License, Version 1.0. (See accompanying -->
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
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<small>Copyright (c) 2006-2009 by Emil Dotchevski and Reverge Studios, Inc.<br/>
Distributed under the <a href="http://www.boost.org/LICENSE_1_0.txt">Boost Software License, Version 1.0</a>.</small>
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