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    CWG Issue 1618</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="1618"></A><H4>1618.
  
Gratuitously-unsigned underlying enum type
</H4>
<B>Section: </B>9.8.1&#160; [<A href="https://wg21.link/dcl.enum">dcl.enum</A>]
 &#160;&#160;&#160;

 <B>Status: </B>C++14
 &#160;&#160;&#160;

 <B>Submitter: </B>Daniel Kr&#252;gler
 &#160;&#160;&#160;

 <B>Date: </B>2013-02-03<BR>


<P>[Moved to DR at the September, 2013 meeting.]</P>



<P>In an enumeration whose underlying type is not fixed, the type of the
first enumerator is unspecified if it has no initializer, meaning that an
implementation could choose either a signed or an unsigned type.  As a
result, the values of <TT>one</TT> and <TT>two</TT> in this example could
be either -1 and 0 or very large unsigned numbers:</P>

<PRE>
  enum { zero, one = zero -1, two };
</PRE>

<P>It would be better if 9.8.1 [<A href="https://wg21.link/dcl.enum#5">dcl.enum</A>] paragraph 5 specified
the type of the first enumerator as a signed type.</P>

<P><B>Proposed resolution (August, 2013):</B></P>

<P>Change 9.8.1 [<A href="https://wg21.link/dcl.enum#5">dcl.enum</A>] paragraph 5 as follows:</P>

<BLOCKQUOTE>

<P>...If the underlying type is not fixed, the type of each enumerator is
the type of its initializing value:</P>

<UL>
<LI><P>If an initializer is specified for an enumerator...</P></LI>

<LI><P>If no initializer is specified for the first enumerator, the
initializing value has an unspecified <INS>signed</INS> integral
type.</P></LI>

<LI><P>Otherwise...</P></LI>

</UL>

</BLOCKQUOTE>

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