Re: [Qemu-devel] [PATCH V2 1/3] Darwin: Fix incorrect check for fdatasync() in configure

[Andreas Färber]

Thanks, applied to the cocoa branch with a modified description.

Am 30.05.2011 um 04:32 schrieb Alexandre Raymond:

> I didn't notice anything broken. I just stumbled upon this bug while
> reviewing the code.
>
> Alexandre
>
> On Sun, May 29, 2011 at 8:09 PM, Alexandre Raymond  
> <address@hidden> wrote:
> > Sure, I'm fine with that. I wasn't sure how much detail you actually
> > wanted in this commit message :)

I like precise explanations, they can be time-saving when bisecting  
code. :)

http://repo.or.cz/w/qemu/afaerber.git/commit/eb5a6b85bb9a409ade5f72cd1b5f827e9bae904c

Andreas

> > On Sun, May 29, 2011 at 7:36 PM, Andreas Färber <address@hidden 
> > > wrote:
> > > Am 30.05.2011 um 00:22 schrieb Alexandre Raymond:
> > >
> > > > Under darwin (OS X 10.6.7), a symbol exists for the fdatasync()  
> > > > method
> > > > but it is not supported because _POSIX_SYNCHRONIZED_IO is set to  
> > > > '-1'.
> > >
> > > Question: How did you notice? Did anything break that we could  
> > > mention, or
> > > did you just review the code?
> > >
> > > > Enable fdatasync() only if _POSIX_SYNCHRONIZED_IO is '>0', as per
> > > > The Open Group Base Specifications Issue 7.
> > >
> > > Not quite what I meant. ;) Would you be okay with the following:
> > >
> > > configure: Fix check for fdatasync()
> > >
> > > Under Darwin, a symbol exists for the fdatasync() function, but it  
> > > is
> > > not supported. Yada yada. _POSIX_SYNCHRONIZED_IO is set to '-1'.
> > >
> > > According to POSIX:2008, a value of -1 means the feature is not  
> > > supported.
> > > A value of 0 means supported at compilation time, and a value  
> > > greater 0
> > > means supported at both compilation and run time.
> > >
> > > Enable fdatasync() only if _POSIX_SYNCHRONIZED_IO is '>0'.
> > >
> > > Andreas
> > >
> > > > Signed-off-by: Alexandre Raymond <address@hidden>
> > > > ---
> > > > configure |    8 +++++++-
> > > > 1 files changed, 7 insertions(+), 1 deletions(-)
> > > >
> > > > diff --git a/configure b/configure
> > > > index a318d37..b21ef75 100755
> > > > --- a/configure
> > > > +++ b/configure
> > > > @@ -2477,7 +2477,13 @@ fi
> > > > fdatasync=no
> > > > cat > $TMPC << EOF
> > > > #include <unistd.h>
> > > > -int main(void) { return fdatasync(0); }
> > > > +int main(void) {
> > > > +#if defined(_POSIX_SYNCHRONIZED_IO) && _POSIX_SYNCHRONIZED_IO > 0
> > > > +return fdatasync(0);
> > > > +#else
> > > > +#abort Not supported
> > > > +#endif
> > > > +}
> > > > EOF
> > > > if compile_prog "" "" ; then
> > > >    fdatasync=yes
> > > > --
> > > > 1.7.5