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    CWG Issue 1234</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="1234"></A><H4>1234.
  
<I>abstract-declarator</I> does not permit <TT>...</TT> after <I>ptr-operator</I>
</H4>
<B>Section: </B>9.3.2&#160; [<A href="https://wg21.link/dcl.name">dcl.name</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++11
 &#160;&#160;&#160;

 <B>Submitter: </B>Johannes Schaub
 &#160;&#160;&#160;

 <B>Date: </B>2011-01-18<BR>


<P>[Voted into the WP at the March, 2011 meeting as part of paper N3262.]</P>



<P>The ellipsis for a parameter pack enters the normal
<I>declarator</I> grammar as part of the <I>declarator-id</I>
nonterminal.  In contrast, however, the <I>abstract-declarator</I>
grammar has no counterpart to <I>declarator-id</I>; instead, the
ellipsis is one of the productions for the <I>abstract-declarator</I>
nonterminal itself.  It is thus impossible to declare a parameter
pack for a pointer or reference using an abstract declarator, e.g.,</P>

<PRE>
  template&lt;typename... T&gt; void f(T&amp; ...t);   //<SPAN CLASS="cmnt"> </SPAN>t<SPAN CLASS="cmnt"> is a parameter pack</SPAN>
  template&lt;typename... T&gt; void f(T&amp; ...);    //<SPAN CLASS="cmnt"> equivalent to </SPAN>void f(T&amp;, ...)
</PRE>

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