Re: preprocessor/10613: Please make -Wtrigraphs the default

[Zack Weinberg <zack at codesourcery dot com>]

The following reply was made to PR preprocessor/10613; it has been noted by GNATS.

From: Zack Weinberg <zack@codesourcery.com>
To: Neil Booth <neil@daikokuya.co.uk>
Cc: Hallvard B Furuseth <h.b.furuseth@usit.uio.no>,  gcc-gnats@gcc.gnu.org,
	  gcc-patches@gcc.gnu.org
Subject: Re: preprocessor/10613: Please make -Wtrigraphs the default
Date: Sun, 04 May 2003 13:55:35 -0700

 Neil Booth <neil@daikokuya.co.uk> writes:
 
 > This is a patch for preprocessor/10613 and preprocessor/10614.  We warn
 > about trigraphs, unless an explicit -trigraphs (or -std implying
 > -trigraphs) is given.  -Wall still implies -Wtrigraphs.
 
 Looks good.  The only thing I have to say is that this bit of
 documentation
 
 > This option is in effect unless trigraphs are turned on, and is
 > implied by @option{-Wall}.  With the exception of a trigraph that
 > would form an escaped newline, warnings are not given for trigraphs
 > within comments as they do not affect the meaning of the program.
 
 is confusing.  I would say instead
 
   Most trigraphs in comments cannot affect the meaning of the program.
   However, a trigraph that would form an escaped newline (@samp{??/}
   at the end of a line) can, by changing where the comment begins or
   ends.  Therefore, only trigraphs that would form escaped newlines
   produce warnings inside a comment.
 
   This option is implied by @option{-Wall}.  If @option{-Wall} is not
   given, this option is still enabled unless trigraphs are enabled.
   To get trigraph conversion without warnings, but get the other
   @option{-Wall} warnings, use @samp{-trigraphs -Wall -Wno-trigraphs}.
 
 zw