🚀 go-pugleaf

In article 331A@strata3d.com, Bret Pehrson <BretP@strata3d.com> writes:
>I just ran across something in my C++ compiler dealing with single line 
>comments and the line continuation token:
>
> if ((ch[0] == '\\') && (ch[1] == '\\'))  //look for initial \\
> {
>   ...
>
>This, under my compiler implementation will choke because of the line 
>continuation token, '\' at the end of the comment.
>
>Can someone please look in their copy of the current C++ 'standard' and tell 
>me if this is correct?

Yes, it is a consequence of the phases of translation. Escaped newlines
are handled by pasting lines together before comments are removed, the
same as in C. (When C adds '//' comments, I expect it to have the same
behavior.)

The phases of translation were very carefully worked out by the ANSI C
committee for the C standard, and any change causes various things to break
or otherwise behave strangely. The fragility is due to interactions among
	trigraphs
	escaped newlines
	escaped characters in strings or character constants
	macro expansion.

In C++, simply don't use '//' comments on any line that ends with an
escaped newline (including macro definitions!). In your example, it would
make the comment more readable IMHO if you put the '\\' in quotes anyway,
and would eliminate the problem.

---
Steve Clamage, stephen.clamage@eng.sun.com
---
[ comp.std.c++ is moderated.  To submit articles: Try just posting with your 
                newsreader.  If that fails, use mailto:std-c++@ncar.ucar.edu
  comp.std.c++ FAQ: http://reality.sgi.com/austern/std-c++/faq.html
  Moderation policy: http://reality.sgi.com/austern/std-c++/policy.html
  Comments? mailto:std-c++-request@ncar.ucar.edu 
]