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    CWG Issue 2791</TITLE>
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<P><EM>This is an unofficial snapshot of the ISO/IEC JTC1 SC22 WG21
  Core Issues List revision 118b.
  See http://www.open-std.org/jtc1/sc22/wg21/ for the official
  list.</EM></P>
<P>2025-09-28</P>
<HR>
<A NAME="2791"></A><H4>2791.
  
Unclear phrasing about "returning to the caller"
</H4>
<B>Section: </B>8.8.4&#160; [<A href="https://wg21.link/stmt.return">stmt.return</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD7
 &#160;&#160;&#160;

 <B>Submitter: </B>Jan Schultke
 &#160;&#160;&#160;

 <B>Date: </B>2023-08-23<BR>


<P>[Accepted as a DR at the November, 2023 meeting.]</P>

<P>In 8.8.4 [<A href="https://wg21.link/stmt.return">stmt.return</A>] and 8.8.5 [<A href="https://wg21.link/stmt.return.coroutine">stmt.return.coroutine</A>], the
standard uses the phrasing "returns to its caller" when
specifying <TT>return</TT> or <TT>co_return</TT>.  It would be better
to talk about transfer of control, which is a term used elsewhere in
the standard.</P>

<P><B>Proposed resolution (approved by CWG 2023-10-06):</B></P>

<OL>
<LI>
<P>Change in 7.6.2.4 [<A href="https://wg21.link/expr.await#1">expr.await</A>] paragraph 1 as follows:</P>

<BLOCKQUOTE>

The co_await expression is used to suspend evaluation of a coroutine
(9.6.4 [<A href="https://wg21.link/dcl.fct.def.coroutine">dcl.fct.def.coroutine</A>]) while awaiting completion of the
computation represented by the operand expression.
<INS>Suspending the evaluation of a coroutine transfers control to its
caller or resumer.</INS>

</BLOCKQUOTE>

</LI>

<LI>
<P>Change 8.8.4 [<A href="https://wg21.link/stmt.return#1">stmt.return</A>] paragraph 1 as follows:</P>

<BLOCKQUOTE>

A function returns <INS>control</INS> to its caller by the return statement.

</BLOCKQUOTE>
</LI>

<LI>
<P>Change 8.8.5 [<A href="https://wg21.link/stmt.return.coroutine#1">stmt.return.coroutine</A>] paragraph 1 as follows:</P>

<BLOCKQUOTE>

<DEL>A coroutine returns to its caller or resumer
(9.6.4 [<A href="https://wg21.link/dcl.fct.def.coroutine">dcl.fct.def.coroutine</A>]) by the <TT>co_return</TT> statement or when
suspended (7.6.2.4 [<A href="https://wg21.link/expr.await">expr.await</A>]).</DEL>
<INS>A <TT>co_return</TT> statement transfers control to the caller or
resumer of a coroutine (9.6.4 [<A href="https://wg21.link/dcl.fct.def.coroutine">dcl.fct.def.coroutine</A>]).</INS> A coroutine
shall not enclose a <TT>return</TT> statement
(8.8.4 [<A href="https://wg21.link/stmt.return">stmt.return</A>]).

</BLOCKQUOTE>
</LI>

<LI>

<P>Change in 9.6.4 [<A href="https://wg21.link/dcl.fct.def.coroutine#10">dcl.fct.def.coroutine</A>] paragraph 10 as follows:</P>

<BLOCKQUOTE>

If the allocation function returns nullptr, the
coroutine <DEL>returns</DEL> <INS>transfers</INS> control to the
caller of the coroutine and the return value is obtained by a call to
<TT>T::get_return_object_on_allocation_failure()</TT>, where T is the
promise type.

</BLOCKQUOTE>
</LI>

</OL>

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