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    CWG Issue 509</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="509"></A><H4>509.
  
Dead code in the specification of default initialization
</H4>
<B>Section: </B>9.5&#160; [<A href="https://wg21.link/dcl.init">dcl.init</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD1
 &#160;&#160;&#160;

 <B>Submitter: </B>Mike Miller
 &#160;&#160;&#160;

 <B>Date: </B>18 Mar 2005<BR>


<P>[Voted into the WP at the September, 2008 meeting (resolution
in paper N2762).]</P>

<P>The definition of default initialization (9.5 [<A href="https://wg21.link/dcl.init#5">dcl.init</A>] paragraph 5)
 is:</P>

<BLOCKQUOTE>

<UL>

<LI><P>if <TT>T</TT> is a non-POD class type (Clause 11 [<A href="https://wg21.link/class">class</A>]), the default constructor for <TT>T</TT> is called (and the
initialization is ill-formed if <TT>T</TT> has no accessible default
constructor);</P></LI>

<LI><P>if <TT>T</TT> is an array type, each element is
default-initialized;</P></LI>

<LI><P>otherwise, the object is zero-initialized.</P></LI>

</UL>

</BLOCKQUOTE>

<P>However, default initialization is invoked only for non-POD class
types and arrays thereof (7.6.2.8 [<A href="https://wg21.link/expr.new#15">expr.new</A>] paragraph 15
for <I>new-expression</I>s, 9.5 [<A href="https://wg21.link/dcl.init#10">dcl.init</A>] paragraph 10
for top-level objects, and 11.9.3 [<A href="https://wg21.link/class.base.init#4">class.base.init</A>] paragraph 4
for member and base class subobjects&#160;&#8212; but see
<A HREF="510.html">issue 510</A>).  Consequently, all cases that
invoke default initialization are handled by the first two bullets;
the third bullet can never be reached.  Its presence is misleading, so
it should be removed.</P>

<P><B>Notes from the September, 2008 meeting:</B></P>

<P>The approach adopted in the resolution in paper N2762 was
different from the suggestion above: it changes the definition of
default initialization to include POD types and changes the third
bullet to specify that &#8220;no initialization is
performed.&#8221;</P>

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