ceph/src/boost/libs/exception/doc/current_exception.html

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  17 <h1>Boost Exception</h1>
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  19 <!-- Copyright (c) 2006-2009 Emil Dotchevski and Reverge Studios, Inc. -->
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  22 <div class="RenoIncludeDIV"><div class="RenoAutoDIV"><h3>current_exception</h3>
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  24 <div class="RenoIncludeDIV"><p><span class="RenoEscape">&#35;<!--<wiki>`&#35;</wiki>--></span>include &lt;<span class="RenoLink"><a href="boost_exception_ptr_hpp.html">boost/exception_ptr.hpp</a></span>&gt;</p>
  25 <pre>namespace
  26 boost
  27     {
  28 <span class="RenoIncludeSPAN">    <span class="RenoLink"><a href="exception_ptr.html">exception_ptr</a></span> <span class="RenoLink">current_exception</span>();</span>
  29     }</pre>
  30 </div><h4>Requirements:</h4>
  31 <p>The <span class="RenoLink">current_exception</span> function must not be called outside of a catch block.</p>
  32 <p>In addition, to safely copy an exception from one thread to another, if the exception object is copied by <span class="RenoLink">current_exception</span> or <span class="RenoLink"><a href="copy_exception.html">copy_exception</a></span>, the two copies must not have shared state. Exceptions that have value-type semantics (as well as the boost::<span class="RenoLink"><a href="exception.html">exception</a></span> type itself) satisfy this requirement.</p>
  33 <h4>Returns:</h4>
  34 <div><ul><li> An <span class="RenoLink"><a href="exception_ptr.html">exception_ptr</a></span> that refers to the currently handled exception or a copy of the currently handled exception.</li>
  35 <li> If the function needs to allocate memory and the attempt fails, it returns an <span class="RenoLink"><a href="exception_ptr.html">exception_ptr</a></span> that refers to an instance of std::bad_alloc.</li>
  36 </ul></div>
  37 <h4>Throws:</h4>
  38 <p>Nothing.</p>
  39 <h4>Notes:</h4>
  40 <div><ul><li> It is unspecified whether the return values of two successive calls to <span class="RenoLink">current_exception</span> refer to the same exception object.</li>
  41 <li> Correct implementation of <span class="RenoLink">current_exception</span> may require compiler support, unless <span class="RenoLink"><a href="enable_current_exception.html">enable_current_exception</a></span> was used at the time the currently handled exception object was passed to throw. Whenever <span class="RenoLink">current_exception</span> fails to properly copy the current exception object, it returns an <span class="RenoLink"><a href="exception_ptr.html">exception_ptr</a></span> to an object of type that is as close as possible to the original exception type, using <span class="RenoLink"><a href="unknown_exception.html">unknown_exception</a></span> as a final fallback. All such types derive from boost::<span class="RenoLink"><a href="exception.html">exception</a></span>, and:<div><ul><li> if the original exception object derives from boost::<span class="RenoLink"><a href="exception.html">exception</a></span>, then the boost::<span class="RenoLink"><a href="exception.html">exception</a></span> sub-object of the object referred to by the returned <span class="RenoLink"><a href="exception_ptr.html">exception_ptr</a></span> is initialized by the boost::<span class="RenoLink"><a href="exception.html">exception</a></span> copy constructor;</li>
  42 <li> if available, the exception contains the std::type_info of the original exception object, accessible through <span class="RenoLink"><a href="get_error_info.html">get_error_info</a></span>&lt;<span class="RenoLink"><a href="original_exception_type.html">original_exception_type</a></span>&gt;.</li>
  43 </ul></div>
  44 </li>
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  47 See also: <span class="RenoPageList"><a href="boost-exception.html">Boost Exception</a>&nbsp;| <a href="boost_exception_ptr_hpp.html">boost/exception_ptr.hpp</a>&nbsp;| <a href="copy_exception.html">copy_exception</a>&nbsp;| <a href="enable_current_exception.html">enable_current_exception</a>&nbsp;| <a href="frequently_asked_questions.html">Frequently Asked Questions</a>&nbsp;| <a href="original_exception_type.html">original_exception_type</a>&nbsp;| <a href="unknown_exception.html">unknown_exception</a></span>
  48 </div>
  49 <!-- Copyright (c) 2006-2009 Emil Dotchevski and Reverge Studios, Inc. -->
  50 <!-- Distributed under the Boost Software License, Version 1.0. (See accompanying -->
  51 <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
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  56 <small>Copyright (c) 2006-2009 by Emil Dotchevski and Reverge Studios, Inc.<br/>
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