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    CWG Issue 2282</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="2282"></A><H4>2282.
  
Consistency with mismatched aligned/non-over-aligned allocation/deallocation functions
</H4>
<B>Section: </B>7.6.2.8&#160; [<A href="https://wg21.link/expr.new">expr.new</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++20
 &#160;&#160;&#160;

 <B>Submitter: </B>Richard Smith
 &#160;&#160;&#160;

 <B>Date: </B>2016-06-27<BR>


<P>[Adopted as a DR at the November, 2019 meeting.]</P>



<P>The fallback treatment for alignment and non-alignment
allocation and deallocation functions is asymmetric. While a
deletion of a non-overaligned class object will match a
class-specific alignment deallocation function if no
class-specific non-alignment deallocation function is
provided, the same is not true for allocation: a
<I>new-expression</I> for a non-overaligned class type will
fail if an alignment allocation function is provided with no
non-alignment allocation function. The allocation behavior
should be changed to match the deallocation behavior.</P>

<P><B>Proposed resolution (September, 2019):</B></P>

<P>Change 7.6.2.8 [<A href="https://wg21.link/expr.new#18">expr.new</A>] paragraph 18 as follows, splitting
the running text into bullets:</P>

<BLOCKQUOTE>

<P>Overload resolution is performed on a function call created
by assembling an argument list. The first argument is the
amount of space requested, and has type <TT>std::size_t</TT>. If the
type of the allocated object has new-extended alignment, the
next argument is the type's alignment, and has type
<TT>std::align_val_t</TT>. If the <I>new-placement</I> syntax is
used, the <I>initializer-clause</I>s in
its <I>expression-list</I> are the succeeding arguments.  If
no matching function is found <INS>then</INS>
</P>

<UL>
<LI><P>
<DEL>and</DEL> <INS>if</INS> the allocated object
type has new-extended alignment, the alignment argument is
removed from the argument list<DEL>,</DEL><INS>;</INS>
</P></LI>

<LI><P><INS>otherwise, an argument list that is the type's alignment
and has type <TT>std::align_val_t</TT> is added into the argument
list immediately after the first argument;</INS></P></LI>

</UL>

<P>and <INS>then</INS> overload resolution is performed
again.</P>

</BLOCKQUOTE>

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