ceph/src/boost/libs/phoenix/doc/html/phoenix/modules/statement/try__catch__statement.html

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  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="phoenix.modules.statement.try__catch__statement"></a><a class="link" href="try__catch__statement.html" title="try_ catch_ Statement">try_
  28         catch_ Statement</a>
  29 </h4></div></div></div>
  30 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">phoenix</span><span class="special">/</span><span class="identifier">statement</span><span class="special">/</span><span class="identifier">try_catch</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
  31 </pre>
  32 <p>
  33           The syntax is:
  34         </p>
  35 <pre class="programlisting"><span class="identifier">try_</span>
  36 <span class="special">[</span>
  37     <span class="identifier">sequenced_statements</span>
  38 <span class="special">]</span>
  39 <span class="special">.</span><span class="identifier">catch_</span><span class="special">&lt;</span><span class="identifier">exception_type</span><span class="special">&gt;()</span>
  40 <span class="special">[</span>
  41     <span class="identifier">sequenced_statements</span>
  42 <span class="special">]</span>
  43 <span class="special">.</span><span class="identifier">catch_</span><span class="special">&lt;</span><span class="identifier">another_exception_type</span><span class="special">&gt;(</span><span class="identifier">local</span><span class="special">-</span><span class="identifier">id</span><span class="special">)</span>
  44 <span class="special">[</span>
  45     <span class="identifier">sequenced_statements</span>
  46 <span class="special">]</span>
  47 <span class="special">...</span>
  48 <span class="special">.</span><span class="identifier">catch_all</span>
  49 <span class="special">[</span>
  50     <span class="identifier">sequenced_statement</span>
  51 <span class="special">]</span>
  52 </pre>
  53 <p>
  54           Note the usual underscore after try and catch, and the extra parentheses
  55           required after the catch.
  56         </p>
  57 <p>
  58           The second form of catch statement can refer thrown exception using specified
  59           local-id, which is <a class="link" href="../scope/local_variables.html" title="Local Variables">Local
  60           Variables</a>, in sequenced_statements.
  61         </p>
  62 <p>
  63           Example: The following code calls the (lazy) function <code class="computeroutput"><span class="identifier">f</span></code>
  64           for each element, and prints messages about different exception types it
  65           catches.
  66         </p>
  67 <pre class="programlisting"><span class="identifier">try_</span>
  68 <span class="special">[</span>
  69     <span class="identifier">f</span><span class="special">(</span><span class="identifier">arg1</span><span class="special">)</span>
  70 <span class="special">]</span>
  71 <span class="special">.</span><span class="identifier">catch_</span><span class="special">&lt;</span><span class="identifier">runtime_error</span><span class="special">&gt;()</span>
  72 <span class="special">[</span>
  73     <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">val</span><span class="special">(</span><span class="string">"caught runtime error or derived\n"</span><span class="special">)</span>
  74 <span class="special">]</span>
  75 <span class="special">.</span><span class="identifier">catch_</span><span class="special">&lt;</span><span class="identifier">exception</span><span class="special">&gt;(</span><span class="identifier">e_</span><span class="special">)</span>
  76 <span class="special">[</span>
  77     <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">val</span><span class="special">(</span><span class="string">"caught exception or derived: "</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">bind</span><span class="special">(&amp;</span><span class="identifier">exception</span><span class="special">::</span><span class="identifier">what</span><span class="special">,</span> <span class="identifier">e_</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="identifier">val</span><span class="special">(</span><span class="string">"\n"</span><span class="special">)</span>
  78 <span class="special">]</span>
  79 <span class="special">.</span><span class="identifier">catch_all</span>
  80 <span class="special">[</span>
  81     <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">val</span><span class="special">(</span><span class="string">"caught some other type of exception\n"</span><span class="special">)</span>
  82 <span class="special">]</span>
  83 </pre>
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  87 <td align="right"><div class="copyright-footer">Copyright &#169; 2002-2005, 2010, 2014, 2015 Joel de Guzman, Dan Marsden, Thomas
  88       Heller, John Fletcher<p>
  89         Distributed under the Boost Software License, Version 1.0. (See accompanying
  90         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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