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<title>Issue 1275: Creating and setting futures</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#Resolved">Resolved</a> status.</em></p>
<h3 id="1275"><a href="lwg-defects.html#1275">1275</a>. Creating and setting futures</h3>
<p><b>Section:</b> 32.10 <a href="https://wg21.link/futures">[futures]</a> <b>Status:</b> <a href="lwg-active.html#Resolved">Resolved</a>
 <b>Submitter:</b> Jonathan Wakely <b>Opened:</b> 2009-11-22 <b>Last modified:</b> 2016-01-28</p>
<p><b>Priority: </b>Not Prioritized
</p>
<p><b>View all other</b> <a href="lwg-index.html#futures">issues</a> in [futures].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#Resolved">Resolved</a> status.</p>
<p><b>Discussion:</b></p>
<p>
 [futures.unique_future]/1 should be updated to mention
<code>async</code>.
</p>

<p>
 [futures.shared_future]/1 should also be updated for
<code>async</code>. That paragraph also says
</p>

<blockquote><p>
... Its value or exception can be set by use of a
<code>shared_future</code>, <code>promise</code> (32.10.6 <a href="https://wg21.link/futures.promise">[futures.promise]</a>), or <code>packaged_task</code> (32.10.10 <a href="https://wg21.link/futures.task">[futures.task]</a>) object that shares the same associated state.
</p></blockquote>

<p>
How can the value be set by a <code>shared_future</code>?
</p>

<p>
99 [futures.atomic_future]/1 says
</p>

<blockquote><p>
An <code>atomic_future</code> object can only be created by use of a
<code>promise</code> (32.10.6 <a href="https://wg21.link/futures.promise">[futures.promise]</a>) or
<code>packaged_task</code> (32.10.10 <a href="https://wg21.link/futures.task">[futures.task]</a>) object.
</p></blockquote>

<p>
which is wrong, it's created from a <code>std::future</code>, which could
have been default-constructed. That paragraph should be closer to the
text of  [futures.shared_future]/1, and should also mention
<code>async</code>.
</p>

<p><i>[
2010 Pittsburgh:  Moved to <del>NAD Editorial</del><ins>Resolved</ins>.  Rationale added below.
]</i></p>




<p><b>Rationale:</b></p>
<p>
Solved by
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3058.html">N3058</a>.
</p>


<p id="res-1275"><b>Proposed resolution:</b></p>





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