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    CWG Issue 1716</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>
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<A NAME="1716"></A><H4>1716.
  
When are default arguments evaluated?
</H4>
<B>Section: </B>9.3.4.7&#160; [<A href="https://wg21.link/dcl.fct.default">dcl.fct.default</A>]
 &#160;&#160;&#160;

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

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

 <B>Date: </B>2013-07-17<BR>


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



<P>According to 9.3.4.7 [<A href="https://wg21.link/dcl.fct.default#9">dcl.fct.default</A>] paragraph 9,</P>

<BLOCKQUOTE>

Default arguments are evaluated each time the function is called.

</BLOCKQUOTE>

<P>Obviously, what was intended by this is that the default argument
is evaluated only if no corresponding actual argument is provided, but
this could be read as indicating that the default argument is evaluated
and discarded by every function call.</P>

<P><B>Proposed resolution (January, 2014):</B></P>

<P>Change 9.3.4.7 [<A href="https://wg21.link/dcl.fct.default#9">dcl.fct.default</A>] paragraph 9 as follows:</P>

<BLOCKQUOTE>

<DEL>Default arguments are</DEL> <INS>A default argument
is</INS> evaluated each time the function is
called <INS>with no argument for the corresponding
parameter</INS>. The order of evaluation...

</BLOCKQUOTE>

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