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    CWG Issue 1615</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="1615"></A><H4>1615.
  
Alignment of types, variables, and members
</H4>
<B>Section: </B>9.13.2&#160; [<A href="https://wg21.link/dcl.align">dcl.align</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD4
 &#160;&#160;&#160;

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

 <B>Date: </B>2013-02-01<BR>


<P>[Moved to DR at the November, 2014 meeting.]</P>



<P>According to 9.13.2 [<A href="https://wg21.link/dcl.align#5">dcl.align</A>] paragraph 5,</P>

<BLOCKQUOTE>

The combined effect of all <I>alignment-specifier</I>s in a declaration
shall not specify an alignment that is less strict than the alignment that
would be required for the entity being declared if
all <I>alignment-specifier</I>s were omitted (including those in other
declarations).

</BLOCKQUOTE>

<P>Presumably the intent was &#8220;other declarations of the same
entity,&#8221; but the wording as written could be read to make the
following example well-formed (assuming <TT>alignof(int)</TT> is 4):</P>

<PRE>
  struct alignas(4) A {
    alignas(8) int n;
  };
  struct alignas(8) B {
    char c;
  };
  alignas(1) B b;
  struct alignas(1) C : B {};
  enum alignas(8) E : int { k };
  alignas(4) E e = k;
</PRE>

<P><B>Proposed resolution (February, 2014):</B></P>

<P>Change 9.13.2 [<A href="https://wg21.link/dcl.align#5">dcl.align</A>] paragraph 5 as follows:</P>

<BLOCKQUOTE>

<P>...if all <I>alignment-specifier</I>s <INS>appertaining to that
entity</INS> were omitted <DEL>(including those in other
declarations)</DEL>. <INS>[<I>Example:</I></INS>
</P>

<PRE>
<INS>  struct alignas(8) S {};
  struct alignas(1) U {
    S s;
  };   //<SPAN CLASS="cmnt"> Error: </SPAN>U<SPAN CLASS="cmnt"> specifies an alignment that is less strict than</SPAN>
       //<SPAN CLASS="cmnt"> if the </SPAN>alignas(1)<SPAN CLASS="cmnt"> were omitted.</SPAN></INS>
</PRE>

<P><INS>&#8212;<I>end example</I>]</INS></P>

</BLOCKQUOTE>

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