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This is an automatically generated e-mail. To reply, visit:
<a href="https://git.reviewboard.kde.org/r/121134/">https://git.reviewboard.kde.org/r/121134/</a>
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<p style="margin-top: 0;">On November 16th, 2014, 8:05 p.m. CET, <b>Pino Toscano</b> wrote:</p>
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<a href="https://git.reviewboard.kde.org/r/121134/diff/3/?file=328834#file328834line323" style="color: black; font-weight: bold; text-decoration: underline;">kdecore/kernel/kglobal.cpp</a>
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(Diff revision 3)
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<td colspan="2"><pre style="font-size: 8pt; line-height: 140%; margin: 0; ">static int s_refCount = 0;</pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="k">static</span> <span class="kt"><span class="hl">i</span>nt</span> <span class="n">s_<span class="hl">refCount</span></span><span class="hl"> </span><span class="o"><span class="hl">=</span></span><span class="hl"> </span><span class="mi"><span class="hl">0</span></span><span class="p">;</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="k">static</span> <span class="n"><span class="hl">QAtomicI</span>nt</span> <span class="n">s_<span class="hl">allowQuit</span></span><span class="p"><span class="hl">(</span></span><span class="mi"><span class="hl">0</span></span><span class="p"><span class="hl">)</span>;</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="k">static</span> <span class="kt">bool</span> <span class="n">s_allowQuit</span> <span class="o">=</span> <span class="nb">false</span><span class="p">;</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="k">static</span> <span class="n">QAtomicInt</span> <span class="nf">s_refCount</span><span class="p">(</span><span class="mi">0</span><span class="p">);</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">QAtomicInt is not a POD, so it is not safe to be used this way. You rather need to use the semi-private QBasicAtomicInt, which is not a POD, like:</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;"><div class="codehilite" style="background: #f8f8f8"><pre style="line-height: 125%"><span style="color: #008000; font-weight: bold">static</span> QBasicAtomicInt s_allowQuit <span style="color: #666666">=</span> Q_BASIC_ATOMIC_INITIALIZER(<span style="color: #666666">0</span>);
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<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">The API should be the same.</p></pre>
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<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">Personal education: what does POD stand for in this context?</p></pre>
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<p>- René J.V.</p>
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<p>On November 16th, 2014, 8:01 p.m. CET, René J.V. Bertin wrote:</p>
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<div>Review request for KDE Software on Mac OS X and kdelibs.</div>
<div>By René J.V. Bertin.</div>
<p style="color: grey;"><i>Updated Nov. 16, 2014, 8:01 p.m.</i></p>
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<b style="color: #575012; font-size: 10pt;">Repository: </b>
kdelibs
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">I have been experiencing unexpected exits from KDevelop that were not due to any kind of error in the KDevelop code; it was as if someone told the application to exit normally. This happens mostly on OS X, but also sometimes on Linux.
I finally traced this to <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">KGlobal::deref</code> reaching a zero reference count and invoking <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">QCoreApplication::quit</code> when called from one of KDevelop's KJob dtors. There does not appear to be a reference counting mismatch in the code, so the issue might be due to a race condition in KGlobal::ref/deref.</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">This patch introduces thread-safety to KGlobal's reference counting by turning the simple global <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">static int s_refCount</code> into a <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">static QAtomicInt s_refCount</code>. I consider this an important bug fix regardless of whether it corrects the issue I have with KDevelop.</p></pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">On OS X 10.6.8 only for now.</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">NB: Qt itself uses the QAtomicInt's parent class (QBasicAtomicInt) for its own reference counter used for implicit sharing. This is thus well-tested code that is unlikely to introduce regressions to a core KDE feature.</p></pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>kdecore/kernel/kglobal.cpp <span style="color: grey">(cf003a4)</span></li>
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<p><a href="https://git.reviewboard.kde.org/r/121134/diff/" style="margin-left: 3em;">View Diff</a></p>
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