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<title>Issue 4133: awaitable-receiver's members are potentially throwing</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#New">New</a> status.</em></p>
<h3 id="4133"><a href="lwg-active.html#4133">4133</a>. <code><i>awaitable-receiver</i></code>'s members are potentially throwing</h3>
<p><b>Section:</b> 33.13.1 <a href="https://wg21.link/exec.as.awaitable">[exec.as.awaitable]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a>
 <b>Submitter:</b> Eric Niebler <b>Opened:</b> 2024-07-30 <b>Last modified:</b> 2024-08-21</p>
<p><b>Priority: </b>1
</p>
<p><b>View other</b> <a href="lwg-index-open.html#exec.as.awaitable">active issues</a> in [exec.as.awaitable].</p>
<p><b>View all other</b> <a href="lwg-index.html#exec.as.awaitable">issues</a> in [exec.as.awaitable].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
The specification of <code><i>awaitable-receiver</i></code> in 33.13.1 <a href="https://wg21.link/exec.as.awaitable">[exec.as.awaitable]</a>/p4 
as of <a href="https://wg21.link/N4988" title=" Working Draft, Programming Languages — C++">N4988</a> is not taking into consideration the fact that the <code>resume()</code> 
and <code>promise()</code> member functions on <code>coroutine_handle&lt;P&gt;</code> are not marked <code>noexcept</code>. 
<code><i>awaitable-receiver</i></code>'s member functions must all be <code>noexcept</code>, but they are 
specified as being "equivalent to" statement that call <code>resume()</code> and <code>promise()</code> 
outside of <code>try</code>/<code>catch</code> blocks.
</p>

<p><i>[2024-08-21; Reflector poll]</i></p>

<p>
Set priority to 1 after reflector poll.
</p>
<p>
<code class='backtick'>promise()</code> can probably be <i>Throws</i>: Nothing
(along with a bunch of other coroutine_handle members),
but <code class='backtick'>resume()</code> certainly can throw.
Also AS-EXCEPT-PTR can throw for the <code class='backtick'>error_code</code> case
(that might be worth a separate issue though).
</p>



<p id="res-4133"><b>Proposed resolution:</b></p>





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