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    CWG Issue 1772</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="1772"></A><H4>1772.
  
<TT>__func__</TT> in a lambda body
</H4>
<B>Section: </B>7.5.6&#160; [<A href="https://wg21.link/expr.prim.lambda">expr.prim.lambda</A>]
 &#160;&#160;&#160;

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

 <B>Submitter: </B>Switzerland/Canada
 &#160;&#160;&#160;

 <B>Date: </B>2013-09-24<BR><BR>


<A href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3903.html#CH5">N3690 comment
  CH&#160;5<BR></A>
<A href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2014/n3903.html#CA22">N3690 comment
  CA&#160;22<BR></A>

<P>[Moved to DR at the February, 2014 meeting.]</P>

<P>It is not clear whether <TT>__func__</TT> in the body of a lambda
refers to the <TT>operator()</TT> of the closure class or
to the containing function (if any).  Since lambdas can appear in
non-function scope, it would be preferable for them to refer to the
closure class's <TT>operator()</TT>.</P>

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

<P>Change 7.5.6 [<A href="https://wg21.link/expr.prim.lambda#7">expr.prim.lambda</A>] paragraph 7 as follows:</P>

<BLOCKQUOTE>

The <I>lambda-expression</I>'s <I>compound-statement</I> yields
the <I>function-body</I>... &#8212;<I>end example</I>] <INS>Further, a
variable <TT>__func__</TT> is implicitly defined at the beginning of
the <I>compound-statement</I> of the <I>lambda-expression</I>, with
semantics as described in 9.6.1 [<A href="https://wg21.link/dcl.fct.def.general">dcl.fct.def.general</A>].</INS>

</BLOCKQUOTE>

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