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    CWG Issue 2093</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="2093"></A><H4>2093.
  
Qualification conversion for pointer-to-member handler matching
</H4>
<B>Section: </B>14.4&#160; [<A href="https://wg21.link/except.handle">except.handle</A>]
 &#160;&#160;&#160;

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

 <B>Submitter: </B>David Majnemer
 &#160;&#160;&#160;

 <B>Date: </B>2015-03-06<BR>


<P>[Adopted at the February, 2016 meeting.]</P>

<P>The criteria for matching an exception handler in
14.4 [<A href="https://wg21.link/except.handle#3">except.handle</A>] paragraph 3 include a qualification
conversion for a handler of pointer or reference to pointer type
but not for a handler of pointer-to-member type.  However, current
implementations permit such conversions.</P>

<P><B>Proposed resolution (October, 2015):</B></P>

<P>Change 14.4 [<A href="https://wg21.link/except.handle#3.3">except.handle</A>] bullet 3.3 as follows:</P>

<BLOCKQUOTE>

<P>A <I>handler</I> is a match for an exception object of
type <TT>E</TT> if</P>

<UL>
<LI><P>...</P></LI>

<LI>

<P>the <I>handler</I> is of type <I>cv</I> <TT>T</TT>
or <TT>const T&amp;</TT> where <TT>T</TT> is a
pointer <INS>or pointer to member</INS> type and <TT>E</TT>
is a pointer <INS>or pointer to member</INS> type that can
be converted to <TT>T</TT> by either or both of</P>
</LI>

<UL>
<LI><P>a standard pointer conversion (7.3.12 [<A href="https://wg21.link/conv.ptr">conv.ptr</A>])
not involving conversions to pointers to private or
protected or ambiguous classes</P></LI>

<LI><P>a qualification
conversion <INS>(7.3.6 [<A href="https://wg21.link/conv.qual">conv.qual</A>])</INS>,
or</P></LI>

</UL>

<LI><P>the <I>handler</I> is...</P></LI>

</UL>

</BLOCKQUOTE>

<P><B>Notes from the October, 2015 meeting:</B></P>

<P>This resolution should not be adopted as a Defect Report,
only a change in the working paper for future revisions of
the Standard, because it could silently change the behavior
of well-defined programs in implementations that conform to
the existing wording.</P>

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