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<td >Qt 5.12</td><td ><a href="qtcore-index.html">Qt Core</a></td><td ><a href="qtcore-module.html">C++ Classes</a></td><td >QScopeGuard</td></tr></table><table class="buildversion"><tr>
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<h3><a name="toc">Contents</a></h3>
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<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#related-non-members">Related Non-Members</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
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<h1 class="title">QScopeGuard Class</h1>
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<p>Provides a scope guard for calling a function at the end of a scope. <a href="#details">More...</a></p>
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<tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QScopeGuard></span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += core</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Since:</td><td class="memItemRight bottomAlign"> Qt 5.12</td></tr></table></div><ul>
<li><a href="qscopeguard-members.html">List of all members, including inherited members</a></li>
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<h2 id="public-functions">Public Functions</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qscopeguard.html#QScopeGuard">QScopeGuard</a></b>(QScopeGuard<F> &&<i>other</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qscopeguard.html#dtor.QScopeGuard">~QScopeGuard</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qscopeguard.html#dismiss">dismiss</a></b>()</td></tr>
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<h2 id="related-non-members">Related Non-Members</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> QScopeGuard<F> </td><td class="memItemRight bottomAlign"><b><a href="qscopeguard.html#qScopeGuardx">qScopeGuard</a></b>(F <i>f</i>)</td></tr>
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<h2 id="details">Detailed Description</h2>
<p>Provides a scope guard for calling a function at the end of a scope.</p>
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<h2>Member Function Documentation</h2>
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<h3 class="fn" id="QScopeGuard"><a name="QScopeGuard"></a>QScopeGuard::<span class="name">QScopeGuard</span>(<span class="type"><a href="qscopeguard.html#QScopeGuard">QScopeGuard</a></span><<span class="type">F</span>> &&<i>other</i>)</h3>
<p>Default constructs an instance of QScopeGuard.</p><!-- @@@QScopeGuard -->
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<h3 class="fn" id="dtor.QScopeGuard"><a name="dtor.QScopeGuard"></a>QScopeGuard::<span class="name">~QScopeGuard</span>()</h3>
<p>Destroys the instance of QScopeGuard.</p><!-- @@@~QScopeGuard -->
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<h3 class="fn" id="dismiss"><a name="dismiss"></a><span class="type">void</span> QScopeGuard::<span class="name">dismiss</span>()</h3>
<p>Disarms the scope guard, so that the function <i>F</i> will not be called at the end of the scope.</p>
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<h2>Related Non-Members</h2>
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<h3 class="fn" id="qScopeGuardx"><a name="qScopeGuardx"></a><span class="type"><a href="qscopeguard.html#QScopeGuard">QScopeGuard</a></span><<span class="type">F</span>> <span class="name">qScopeGuard</span>(<span class="type">F</span> <i>f</i>)</h3>
<p>The qScopeGuard function can be used to call a function at the end of the scope.</p>
<p><a href="qscopeguard.html">QScopeGuard</a><F> is a class which sole purpose is to run a function <i>F</i> in its destructor. This is useful for guaranteeing your cleanup code is executed, whether the function is exited normally, exited early by a return statement, or exited by an exception.</p>
<p>If <i>F</i> is a lambda then you cannot instantiate the template directly, therefore the qScopeGuard() helper is provided and <a href="qscopeguard.html">QScopeGuard</a><F> is made a private implementation detail.</p>
<p>Example usage is as follows:</p>
<pre class="cpp">
<span class="type">void</span> myComplexCodeWithMultipleReturnPoints(<span class="type">int</span> v)
{
<span class="comment">// The lambda will be executed right before your function returns</span>
<span class="keyword">auto</span> cleanup <span class="operator">=</span> qScopeGuard(<span class="operator">[</span><span class="operator">]</span> { code you want executed goes HERE; });
<span class="keyword">if</span> (v <span class="operator">=</span><span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>)
<span class="keyword">return</span>;
<span class="type">int</span> v2 <span class="operator">=</span> code_that_might_throw_exceptions();
<span class="keyword">if</span> (v2 <span class="operator">=</span><span class="operator">=</span> <span class="operator">-</span><span class="number">1</span>)
<span class="keyword">return</span>;
(<span class="operator">.</span><span class="operator">.</span><span class="operator">.</span>)
}
</pre>
<p><b>Note: </b>Exceptions are not supported. The callable shouldn't throw when executed, copied or moved.</p><p><b>See also </b><a href="qscopedvaluerollback.html">QScopedValueRollback</a>.</p>
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