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    CWG Issue 1102</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="1102"></A><H4>1102.
  
Better example of undefined behavior
</H4>
<B>Section: </B>6.10.1&#160; [<A href="https://wg21.link/intro.execution">intro.execution</A>]
 &#160;&#160;&#160;

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

 <B>Submitter: </B>GB
 &#160;&#160;&#160;

 <B>Date: </B>2010-08-02<BR><BR>


<P>[Voted into the WP at the November, 2010 meeting.]</P>

<A href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3296.html#GB6">N3092 comment
  GB&#160;6<BR></A>

<P>There are core issues surrounding the undefined behavior
of dereferencing a null pointer. It appears the intent is
that dereferencing <I>is</I> well defined, but using the result
of the dereference will yield undefined behavior. This topic
is too confused to be the reference example of undefined
behavior, or should be stated more precisely if it is to be
retained.</P>

<P>(See also <A HREF="232.html">issue 232</A>.)</P>

<P><B>Proposed resolution (September, 2010):</B></P>

<P>Change 6.10.1 [<A href="https://wg21.link/intro.execution#4">intro.execution</A>] paragraph 4 as follows:</P>

<BLOCKQUOTE>

Certain other operations are described in this International Standard
as undefined (for example, the effect of <DEL>dereferencing the null
pointer</DEL> <INS>attempting to modify a <TT>const</TT>
object</INS>). [<I>Note:</I>...

</BLOCKQUOTE>

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