<table><tr><td style="">aaronpuchert added inline comments.
</td><a style="text-decoration: none; padding: 4px 8px; margin: 0 8px 8px; float: right; color: #464C5C; font-weight: bold; border-radius: 3px; background-color: #F7F7F9; background-image: linear-gradient(to bottom,#fff,#f1f0f1); display: inline-block; border: 1px solid rgba(71,87,120,.2);" href="https://phabricator.kde.org/D16218">View Revision</a></tr></table><br /><div><strong>INLINE COMMENTS</strong><div><div style="margin: 6px 0 12px 0;"><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D16218#inline-88833">View Inline</a><span style="color: #4b4d51; font-weight: bold;">core.cpp:66</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #74777d">// sense of the term.</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #aa4000">static</span> <span class="n">std</span><span style="color: #aa2211">::</span><span class="n">atomic_bool</span> <span class="n">handlingSignal</span><span class="p">(</span><span style="color: #304a96">false</span><span class="p">);</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #aa4000">int</span> <span class="n">sig</span> <span style="color: #aa2211">=</span> <span class="n">signalReceived</span><span class="p">;</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">The <tt style="background: #ebebeb; font-size: 13px;">atomic_</tt> aliases are provided for compatibility with C code, I'd just use <tt style="background: #ebebeb; font-size: 13px;">std::atomic<bool></tt> directly.</p></div></div><br /><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D16218#inline-88832">View Inline</a><span style="color: #4b4d51; font-weight: bold;">core.cpp:67-69</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #aa4000">int</span> <span class="n">sig</span> <span style="color: #aa2211">=</span> <span class="n">signalReceived</span><span class="p">;</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span class="n">signalReceived</span> <span style="color: #aa2211">=</span> <span style="color: #601200">0</span><span class="p">;</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">Why keep <tt style="background: #ebebeb; font-size: 13px;">signalReceived</tt> if you can get the same value from the pipe?</p></div></div><br /><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D16218#inline-88834">View Inline</a><span style="color: #4b4d51; font-weight: bold;">core.cpp:79-80</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; background: rgba(251, 175, 175, .7);">    <span style="color: #aa4000">if</span> <span class="p">(<span class="bright"></span></span><span class="bright"> </span><span style="color: #aa2211">!</span><span class="n">handlingSignal<span class="bright"></span></span><span class="bright"> </span><span class="p">)</span> <span class="p">{</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(251, 175, 175, .7);">        <span class="n">handlingSignal</span> <span style="color: #aa2211">=</span> <span class="bright"></span><span style="color: #601200"><span class="bright">1</span></span><span class="p">;</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(251, 175, 175, .7);">        <span class="bright"></span><span class="n"><span class="bright">qCDebug</span></span><span class="bright"></span><span class="p"><span class="bright">(</span></span><span class="bright"></span><span class="n"><span class="bright">SHELL</span></span><span class="bright"></span><span class="p"><span class="bright">)</span></span><span class="bright"> </span><span style="color: #aa2211"><span class="bright"><<</span></span><span class="bright"> </span><span style="color: #766510"><span class="bright">"signal "</span></span><span class="bright"> </span><span style="color: #aa2211"><span class="bright"><<</span></span> <span class="n">sig<span class="bright"></span></span><span class="bright"> </span><span style="color: #aa2211"><span class="bright"><<</span></span><span class="bright"> </span><span style="color: #766510"><span class="bright">" received, shutting down gracefully"</span></span><span class="bright"></span><span class="p"><span class="bright">;</span></span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #aa4000">if</span> <span class="p">(</span><span style="color: #aa2211">!</span><span class="n">handlingSignal</span><span class="p">)</span> <span class="p">{</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">        <span class="n">handlingSignal</span> <span style="color: #aa2211">=</span> <span class="bright"></span><span style="color: #304a96"><span class="bright">true</span></span><span class="p">;</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">        <span class="bright"></span><span style="color: #74777d"><span class="bright">// the first time we see a</span> sig<span class="bright">nal we attempt to exit</span></span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">Still not atomic.</p>

<div class="remarkup-code-block" style="margin: 12px 0;" data-code-lang="text" data-sigil="remarkup-code-block"><pre class="remarkup-code" style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; padding: 12px; margin: 0; background: rgba(71, 87, 120, 0.08);">if (!handlingSignal.exchange(true)) {</pre></div></div></div><br /><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D16218#inline-88835">View Inline</a><span style="color: #4b4d51; font-weight: bold;">core.cpp:89-90</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; ">        <span class="n">app</span><span style="color: #aa2211">-></span><span class="n">quit</span><span class="p">();</span>
</div><div style="padding: 0 8px; margin: 0 4px; ">        <span style="color: #aa4000">return</span><span class="p">;</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span class="p">}</span> <span style="color: #aa4000">else</span> <span class="p">{</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">        <span class="n">qCWarning</span><span class="p">(</span><span class="n">SHELL</span><span class="p">)</span> <span style="color: #aa2211"><<</span> <span style="color: #766510">"Going down harder on signal"</span> <span style="color: #aa2211"><<</span> <span class="n">sig</span><span class="p">;</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">No else after return.</p></div></div><br /><div style="border: 1px solid #C7CCD9; border-radius: 3px;"><div style="padding: 0; background: #F7F7F7; border-color: #e3e4e8; border-style: solid; border-width: 0 0 1px 0; margin: 0;"><div style="color: #74777d; background: #eff2f4; padding: 6px 8px; overflow: hidden;"><a style="float: right; text-decoration: none;" href="https://phabricator.kde.org/D16218#inline-88836">View Inline</a><span style="color: #4b4d51; font-weight: bold;">core.cpp:106-112</span></div>
<div style="font: 11px/15px "Menlo", "Consolas", "Monaco", monospace; white-space: pre-wrap; clear: both; padding: 4px 0; margin: 0;"><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #74777d">// NOTE: using signalReceived is not thread-safe. If a 2nd signal comes in</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #74777d">// before the current signal has been processed, shutdownGracefully() will</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #74777d">// see the new value. That is not a problem in this case; the result is that</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #74777d">// the handler uses the last of a "signal burst", which is not unreasonable</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #74777d">// given that this currently makes no difference at all in the graceful</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span style="color: #74777d">// shutdown behaviour.</span>
</div><div style="padding: 0 8px; margin: 0 4px; background: rgba(151, 234, 151, .6);">    <span class="n">signalReceived</span> <span style="color: #aa2211">=</span> <span class="n">sig</span><span class="p">;</span>
</div></div></div>
<div style="margin: 8px 0; padding: 0 12px;"><p style="padding: 0; margin: 8px;">That might be true, but why bother? You write the signal value to the pipe, so you might as well read it on the other end.</p></div></div></div></div></div><br /><div><strong>REPOSITORY</strong><div><div>R32 KDevelop</div></div></div><br /><div><strong>REVISION DETAIL</strong><div><a href="https://phabricator.kde.org/D16218">https://phabricator.kde.org/D16218</a></div></div><br /><div><strong>To: </strong>rjvbb, KDevelop, kfunk<br /><strong>Cc: </strong>aaronpuchert, brauch, kfunk, arrowd, kdevelop-devel, glebaccon, antismap, iodelay, vbspam, geetamc, Pilzschaf, akshaydeo, surgenight<br /></div>