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    CWG Issue 2747</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="2747"></A><H4>2747.
  
Cannot depend on an already-deleted splice
</H4>
<B>Section: </B>5.2&#160; [<A href="https://wg21.link/lex.phases">lex.phases</A>]
 &#160;&#160;&#160;

 <B>Status: </B>CD7
 &#160;&#160;&#160;

 <B>Submitter: </B>Jim X
 &#160;&#160;&#160;

 <B>Date: </B>2021-09-14<BR>


<P>[Accepted as a DR at the November, 2023 meeting.]</P>

<P>(From editorial issue
<A HREF="https://github.com/cplusplus/draft/issues/4903">4903</A>.)</P>

<P>Subclause 5.2 [<A href="https://wg21.link/lex.phases#2">lex.phases</A>] paragraph 2 specifies:</P>

<BLOCKQUOTE>

... Each sequence of a backslash character (\) immediately
followed by zero or more whitespace characters other than new-line
followed by a new-line character is deleted, splicing physical source
lines to form logical source lines. ...  A source
file that is not empty and that does not end in a new-line character,
or that ends in a splice, shall be processed as if an additional
new-line character were appended to the file.

</BLOCKQUOTE>

<P>This is confusing, because the first sentence deletes all splices,
and then the last sentence checks for a splice that has already been
deleted.</P>

<P><B>Proposed resolution (approved by CWG 2023-07-14):</B></P>

<P>Change in 5.2 [<A href="https://wg21.link/lex.phases#2">lex.phases</A>] paragraph 2 as follows:</P>

<BLOCKQUOTE>

... Each sequence of a backslash character (\) immediately
followed by zero or more whitespace characters other than new-line
followed by a new-line character is deleted, splicing physical source
lines to form logical source lines. ...  A source file that is not
empty and that <INS>(after splicing)</INS> does not end in a new-line character<DEL>, or that ends
in a splice,</DEL> shall be processed as
if an additional new-line character were appended to the file.

</BLOCKQUOTE>

<P><B>CWG 2023-07-14</B></P>

<P>CWG noted that a lone backslash at the end of a file remains (in
the status quo and with the proposed change) and turns into an
ill-formed <I>preprocessing-token</I>. The wording as amended seems
sufficiently clear to consider <A HREF="1698.html">issue 1698</A>
resolved.</P>

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