fprintf() crashes on wide-oriented stream.

[Takashi Yano]

On Thu, 5 Oct 2023 19:18:14 +0900
Takashi Yano wrote:
> Hi Jeff,
> 
> Thanks for reviewing and the comment.
> 
> On Wed, 4 Oct 2023 16:16:13 -0400
> Jeff Johnston wrote:
> > I finally took a look at this.  The issue is whether POSIX compliance is
> > desired.
> 
> IIUC, POSIX states that width setting is once decided, it cannot be
> changed until the stream is closed. However, nothing is stated what
> should happen when different width data is output into the stream.
> 
> > Corinna would have
> > strong opinions that it is desired and thus, I think she should have her
> > say when she gets back.  I personally believe that
> > newlib should have behaved like glibc.  I also think the test snippet is
> > invalid and should have performed an fwide call on stdout
> > to reset the wide-orientation and have the code work properly in all cases.
> 
> Currently, fputs and fputc works even for wide-oriended stream, so to
> be consistent with that, fprintf also might be better to work.
> 
> I wouldn't necessarily expect fprintf to work on wide-oriented streams,
> but buffer overruns should not happen anyway.
> 
> So, newlib should be fixed either way.

As a test, I made a patch attached to make it behave like glibc.
What do you think?

-- 
Takashi Yano <takashi.yano@nifty.ne.jp>
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