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<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
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<h1 class="title">Exception Class Reference</h1>
<span class="small-subtitle">(QtConcurrent::Exception)<br/></span>
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<p>The Exception class provides a base class for exceptions that can transferred across threads. <a href="#details">More...</a></p>
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<p><b>Inherited by: </b><a href="qtconcurrent-unhandledexception.html">QtConcurrent::UnhandledException</a>.</p>
<p>This class was introduced in Qt 4.4.</p>
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<h2>Public Functions</h2>
<table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> virtual Exception * </td><td class="memItemRight bottomAlign"><b><a href="qtconcurrent-exception.html#clone">clone</a></b> () const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual void </td><td class="memItemRight bottomAlign"><b><a href="qtconcurrent-exception.html#raise">raise</a></b> () const</td></tr>
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<h2>Detailed Description</h2>
<p>The Exception class provides a base class for exceptions that can transferred across threads.</p>
<p>Qt Concurrent supports throwing and catching exceptions across thread boundaries, provided that the exception inherit from QtConcurrent::Exception and implement two helper functions:</p>
<pre class="cpp"> <span class="keyword">class</span> MyException : <span class="keyword">public</span> <span class="type"><a href="qtconcurrent.html">QtConcurrent</a></span><span class="operator">::</span>Exception
{
<span class="keyword">public</span>:
<span class="type">void</span> raise() <span class="keyword">const</span> { <span class="keyword">throw</span> <span class="operator">*</span><span class="keyword">this</span>; }
Exception <span class="operator">*</span>clone() <span class="keyword">const</span> { <span class="keyword">return</span> <span class="keyword">new</span> MyException(<span class="operator">*</span><span class="keyword">this</span>); }
};</pre>
<p>QtConcurrent::Exception subclasses must be thrown by value and caught by reference:</p>
<pre class="cpp"> <span class="keyword">try</span> {
<span class="type"><a href="qtconcurrent.html">QtConcurrent</a></span><span class="operator">::</span>blockingMap(list<span class="operator">,</span> throwFunction); <span class="comment">// throwFunction throws MyException</span>
} <span class="keyword">catch</span> (MyException <span class="operator">&</span>e) {
<span class="comment">// handle exception</span>
}</pre>
<p>If you throw an exception that is not a subclass of QtConcurrent::Exception, the Qt Concurrent functions will throw a <a href="qtconcurrent-unhandledexception.html">QtConcurrent::UnhandledException</a> in the receiver thread.</p>
<p>When using <a href="qfuture.html">QFuture</a>, transferred exceptions will be thrown when calling the following functions:</p>
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<li><a href="qfuture.html#waitForFinished">QFuture::waitForFinished</a>()</li>
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<h2>Member Function Documentation</h2>
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<h3 class="fn"><a name="clone"></a><span class="type">Exception</span> * Exception::<span class="name">clone</span> () const<tt> [virtual]</tt></h3>
<p>In your <a href="qtconcurrent-exception.html">QtConcurrent::Exception</a> subclass, reimplement clone() like this:</p>
<pre class="cpp"> MyException <span class="operator">*</span>MyException<span class="operator">::</span>clone() <span class="keyword">const</span> { <span class="keyword">return</span> <span class="keyword">new</span> MyException(<span class="operator">*</span><span class="keyword">this</span>); }</pre>
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<h3 class="fn"><a name="raise"></a><span class="type">void</span> Exception::<span class="name">raise</span> () const<tt> [virtual]</tt></h3>
<p>In your <a href="qtconcurrent-exception.html">QtConcurrent::Exception</a> subclass, reimplement raise() like this:</p>
<pre class="cpp"> <span class="type">void</span> MyException<span class="operator">::</span>raise() <span class="keyword">const</span> { <span class="keyword">throw</span> <span class="operator">*</span><span class="keyword">this</span>; }</pre>
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