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<div id="projectname">libsigc++
 <span id="projectnumber">2.2.11</span>
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<div class="title">exception_catch()</div> </div>
<div class="ingroups"><a class="el" href="group__adaptors.html">Adaptors</a></div></div><!--header-->
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<p>sigc::exception_catch() catches an exception thrown from within the wrapped functor and directs it to a catcher functor. <a href="#details">More...</a></p>
<p>sigc::exception_catch() catches an exception thrown from within the wrapped functor and directs it to a catcher functor. </p>
<p>This catcher can then rethrow the exception and catch it with the proper type.</p>
<p>Note that the catcher is expected to return the same type as the wrapped functor so that normal flow can continue.</p>
<p>Catchers can be cascaded to catch multiple types, because uncaught rethrown exceptions proceed to the next catcher adaptor.</p>
<dl class="section user"><dt>Examples:</dt><dd><div class="fragment"><div class="line"> <span class="keyword">struct </span>my_catch</div>
<div class="line"> {</div>
<div class="line"> <span class="keywordtype">int</span> operator()()</div>
<div class="line"> {</div>
<div class="line"> <span class="keywordflow">try</span> { <span class="keywordflow">throw</span>; }</div>
<div class="line"> <span class="keywordflow">catch</span> (<a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a00915.html">std::range_error</a> e) <span class="comment">// catch what types we know</span></div>
<div class="line"> { <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01622.html#a7431d56d1e8cd7a9b854171294bd71c7">std::cerr</a> << <span class="stringliteral">"caught "</span> << e.<a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a00934.html#a45f5b9c4b7141ac429bf6ea99a7ff6bf">what</a>() << <a class="codeRef" doxygen="libstdc++.tag:http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/" href="http://gcc.gnu.org/onlinedocs/libstdc++/latest-doxygen/a01622.html#a8b3758bb8f17c440c7963363f42f69f3">std::endl</a>; }</div>
<div class="line"> <span class="keywordflow">return</span> 1;</div>
<div class="line"> }</div>
<div class="line"> }</div>
<div class="line"> <span class="keywordtype">int</span> foo(); <span class="comment">// throws std::range_error</span></div>
<div class="line"> sigc::exception_catch(&foo, my_catch())();</div>
</div><!-- fragment --></dd></dl>
<p>The functor sigc::exception_catch() returns can be directly passed into <a class="el" href="classsigc_1_1signal7.html#adc55ac9b0f935fd87a67904022e03cb2" title="Add a slot to the list of slots.">sigc::signal::connect()</a>.</p>
<dl class="section user"><dt>Example:</dt><dd><div class="fragment"><div class="line"> <a class="code" href="classsigc_1_1signal.html" title="Convenience wrapper for the numbered sigc::signal# templates.">sigc::signal<int></a> some_signal;</div>
<div class="line"> some_signal.<a class="code" href="classsigc_1_1signal7.html#adc55ac9b0f935fd87a67904022e03cb2" title="Add a slot to the list of slots.">connect</a>(sigc::exception_catch(&foo, my_catch));</div>
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