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    CWG Issue 737</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="737"></A><H4>737.
  
Uninitialized trailing characters in string initialization
</H4>
<B>Section: </B>9.5.3&#160; [<A href="https://wg21.link/dcl.init.string">dcl.init.string</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD2
 &#160;&#160;&#160;

 <B>Submitter: </B>James Kanze
 &#160;&#160;&#160;

 <B>Date: </B>26 October, 2008<BR>


<P>[Voted into WP at October, 2009 meeting.]</P>



<P>The current specification of string initialization in 9.5.3 [<A href="https://wg21.link/dcl.init.string">dcl.init.string</A>] leaves uninitialized all characters following the
terminating <TT>'\0'</TT> of a character array with automatic storage
duration.  This is different from C99, in which string initialization
is handled like aggregate initialization and all trailing characters
are zeroed (6.7.8 paragraph 21).</P>

<P>(See also <A HREF="694.html">issue 694</A>, in which we
are considering following C99 in a somewhat similar case of
zero-initializing trailing data.)</P>

<P><B>Proposed resolution (September, 2009):</B></P>

<P>Add a new paragraph following 9.5.3 [<A href="https://wg21.link/dcl.init.string#2">dcl.init.string</A>] paragraph 2:</P>

<BLOCKQUOTE>

<P>There shall not be more initializers than there are array elements. [<I>Example:</I>
</P>

<PRE>
  char cv[4] = "asdf";    //<SPAN CLASS="cmnt"> error</SPAN>
</PRE>

<P>is ill-formed since there is no space for the implied trailing '\0'.
&#8212;<I>end example</I>]</P>

<P><INS>If there are fewer initializers than there are array elements,
then each element not explicitly initialized shall be zero-initialized
(9.5 [<A href="https://wg21.link/dcl.init">dcl.init</A>]).</INS></P>

</BLOCKQUOTE>

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