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    CWG Issue 628</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="628"></A><H4>628.
  
The values of an enumeration with no enumerator
</H4>
<B>Section: </B>9.8.1&#160; [<A href="https://wg21.link/dcl.enum">dcl.enum</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD2
 &#160;&#160;&#160;

 <B>Submitter: </B>Gennaro Prota
 &#160;&#160;&#160;

 <B>Date: </B>15 March 2007<BR><BR>


<A href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2010/n3086.html#UK96">N2800 comment
  UK&#160;96<BR></A>

<P>[Voted into the WP at the March, 2009 meeting.]</P>

<P>According to 9.8.1 [<A href="https://wg21.link/dcl.enum#6">dcl.enum</A>] paragraph 6, the underlying
type of an enumeration with an empty <I>enumeration-list</I> is
determined as if the <I>enumeration-list</I> contained a single
enumerator with value 0.  Paragraph 7, which specifies the values of
an enumeration and the minimum size of bit-field needed represent
those values needs a similar provision for
empty <I>enumeration-list</I>s.</P>

<P><B>Proposed resolution (March, 2008):</B></P>

<P>Add the indicated sentence to the end of 9.8.1 [<A href="https://wg21.link/dcl.enum#5">dcl.enum</A>] paragraph 5:
</P>

<BLOCKQUOTE>

...It is possible to define an enumeration that has values not defined
by any of its enumerators.  <INS>If the <I>enumerator-list</I> is empty,
the values of the enumeration are as if the enumeration had a single
enumerator with value 0.</INS>

</BLOCKQUOTE>

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