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Re: error: "no newline at end of file"
On 27/03/07, Joe Buck <Joe.Buck@synopsys.com> wrote:
On Tue, Mar 27, 2007 at 02:23:47PM +0100, Manuel López-Ibáñez wrote:
> On 27/03/07, Martin Michlmayr <tbm@cyrius.com> wrote:
> >* Manuel López-Ibáñez <lopezibanez@gmail.com> [2007-03-27 14:08]:
> >> C++ preprocessor emits errors by default for nonconformant code,
> >> following the C++ frot-end default behaviour. Users can use the
> >> -fpermissive option to downgrade these diagnostics from errors to
> >> warnings.
> >
> >s/frot-end/front-end/
> >
> >I'm not sure whether "nonconformant code" is specific enough. Apart
> >from this, it looks good.
>
> It comes from the definition of fpermissive in invoke.texi.
Users aren't going to know from this language what has changed. Manuel,
since you're the guy who has been studying the warnings lately: which
other preprocessor diagnostics, other than "no newline at end of file",
are affected by this change?
I would suggest language like:
Certain nonconformant code detected by the C++ preprocessor, such as
"no newline at end of file", that were formerly warnings are now hard
errors. Users can use the -fpermissive option to downgrade these
diagnostics from errors to warnings.
If there are two or three more, the affected diagnostics could be listed
as bullet items.
There aren't two or three. Any pedwarn has become an error. That is
how the C++ front-end works. Perhaps it is not how the C++ front-end
was intended to work but I have checked the C++ front-end code and it
does indeed emit errors for pedwarns even when -pedantic was not given
in the command line.
manuel@gcc05:~/src/trunk$ cat /home/manuel/src/test.cc
extern void f(void);
static void f(void);
manuel@gcc05:~/src/trunk$ /n/b01/guerby/release/3.4.6/bin/g++ -c ~/src/test.cc
/home/manuel/src/test.cc:3: error: `void f()' was declared `extern'
and later `static'
/home/manuel/src/test.cc:1: error: previous declaration of `void f()'
manuel@gcc05:~/src/trunk$ /n/b01/guerby/release/3.4.6/bin/g++
-fpermissive -c ~/src/test.cc
/home/manuel/src/test.cc:3: warning: `void f()' was declared `extern'
and later `static'
/home/manuel/src/test.cc:1: warning: previous declaration of `void f()'
In GCC 4.3 the C++ preprocessor works like the C++ front-end, pedwarns
are errors by default. Now, if the C++ front-end behaviour was already
incorrect, that is a different issue altogether. Fixing this in both
the C++ front-end and preprocessor seems fairly simple to me, if that
is what we really want to do but it is going to change from errors to
warnings a lot of pedwarns that have been errors since GCC 3.4.6 at
least.
I think we should consider this first and once there is a decision
made, we can think about what to say in the changes page and what to
do with the nonewline warning.
Cheers,
Manuel.