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<title>Issue 1471: Default constructor of atomics needs specification</title>
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<p><em>This page is a snapshot from the LWG issues list, see the <a href="lwg-active.html">Library Active Issues List</a> for more information and the meaning of <a href="lwg-active.html#NAD_Editorial">NAD Editorial</a> status.</em></p>
<h3 id="1471"><a href="lwg-closed.html#1471">1471</a>. Default constructor of atomics needs specification</h3>
<p><b>Section:</b> 32.5.8.2 <a href="https://wg21.link/atomics.types.operations">[atomics.types.operations]</a> <b>Status:</b> <a href="lwg-active.html#NAD_Editorial">NAD Editorial</a>
 <b>Submitter:</b> INCITS <b>Opened:</b> 2010-08-25 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View other</b> <a href="lwg-index-open.html#atomics.types.operations">active issues</a> in [atomics.types.operations].</p>
<p><b>View all other</b> <a href="lwg-index.html#atomics.types.operations">issues</a> in [atomics.types.operations].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#NAD Editorial">NAD Editorial</a> status.</p>
<p><b>Discussion:</b></p>
<p><b>Addresses US-168</b></p>

<p>
32.5.8.2 <a href="https://wg21.link/atomics.types.operations">[atomics.types.operations]</a> around p. 4: The definition of the default constructor needs exposition.
</p>


<p id="res-1471"><b>Proposed resolution:</b></p>
<p>
Insert a new general prototype description following the current 32.5.8.2 <a href="https://wg21.link/atomics.types.operations">[atomics.types.operations]</a> p. 3 as indicated:
</p>
<blockquote><p>
3 [<em>Note</em>: Many operations are volatile-qualified. The “volatile as device register” semantics have not changed
in the standard. This qualification means that volatility is preserved when applying these operations to
volatile objects. It does not mean that operations on non-volatile objects become volatile. Thus, volatile
qualified operations on non-volatile objects may be merged under some conditions. -- <em>end note</em>]
</p></blockquote>
<blockquote><pre>
<ins>A::A() = default;</ins>
</pre><blockquote><p>
<ins>? <em>Effects</em>: Leaves the atomic object in an uninitialized state.
[<em>Note</em>: These semantics ensure compatiblity with <code>C</code>. -- <em>end note</em>]</ins>
</p></blockquote></blockquote>
<blockquote><pre>
constexpr A::A(C desired);
[..]
</pre></blockquote>





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