Problem with line buffering and getc function on 1.7.33.

Corinna Vinschen
Sun Mar 13 11:37:00 GMT 2016

On Mar 13 12:06, Corinna Vinschen wrote:
> On Mar 12 16:41, Kaz Kylheku wrote:
> > On 12.03.2016 14:29, Corinna Vinschen wrote:
> > >I do now.  Basically it's setvbuf screwing up the internal flags in the
> > >FILE structure.  I took the liberty to update newlib's setvbuf to the
> > >OpenBSD version locally and I'm going to apply my patches to newlib
> > >soon.  I'll provide a new 2.5.0 test release of Cygwin with this patch
> > >tomorrow or early next week.
> > 
> > The change in git now seems risky; it substantially rewrites setvbuf.
> > Of course, it's not that I think OpenBSD has it wrong, but that it's
> > being cherry-picked in isolation into what looks like a code base
> > with some other old pieces. Just a thought.
> Point taken.  I compared the code carefully and I'm reasonable sure
> that the risk is low.  The major differences to the old setvbuf are:
> - The locking call is later.  The first check potenitally exiting
>   the function early does not need any access to either reent or fp.
> - OpenBSD setvbuf now drops the ungetc buffer.
> - OpenBSD resets more flags, namely __SOPT | __SNPT | __SEOF.  That's
>   certainly the safer option.
> - Optimal IO size handling is a bonus.  Just setting buffer to 1K was
>   a bit sub-optimal.
> - Add missing __sinit() call.
> - Only set buffersize to non-0 in _IOLBF case if we're already writing.
> - The rest is equivalent to before.  Only the switch statement has been
>   changed to an if in OpenBSD's setvbuf.
> Did you try Cygwin 2.0.5-0.6?



Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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