[MPlayer-dev-eng] [PATCH] Use unrar for open vobsubs if available

[Ulion]

2007/12/8, Reimar Doeffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de>:
> On Fri, Dec 07, 2007 at 11:11:45PM +0800, Ulion wrote:
> > 2007/12/7, Reimar Doeffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de>:
> > > On Fri, Dec 07, 2007 at 07:24:32PM +0800, Ulion wrote:
> > > > > No, none of them need to be closed. All you need to do is replace stderr instead of
> > > > > closing.
> > > > > So something like
> > > > > > fd = open("/dev/null", O_WRONLY);
> > > > > > if (fd < 3) _exit(EXIT_FAILURE);
> > > > > > dup2(fd, 2);
> > > > > > close(fd);
> > > > > should do it.
> > > > > Note that this will cause MPlayer to fail if it was started without
> > > > > stdin, stdout or stderr itself (though I don't think we really need
> > > > > to care about that).
> > > >
> > > > dup2() will close target fd if it's openen. So current code looks ok for me:
> > > >         /* suppress stderr messages */
> > > >         close(2);
> > > >         fd = open("/dev/null", O_WRONLY);
> > > >         if(fd != 2) {
> > > >             if (dup2(fd, 2))
> > > >                 _exit(EXIT_FAILURE);
> > > >             close(fd);
> > > >         }
> > > >
> > > > Is it ok for you?
> > >
> > > No, not really. Your code is already like that more complex, but it also handles
> > > the case that open fails only implicitly, which is more fragile, and with the
> > > dup2 test removed it is just plain broken.
> >
> > How about:
> >
> >         fd = open("/dev/null", O_WRONLY);
> >         if(fd == -1)
> >             _exit(EXIT_FAILURE);
> >         if (fd != 2) {
> >             dup2(fd, 2);
> >             close(fd);
> >         }
>
> What is the point of the != 2 check then? Either you assume that
> stdin, stdout and stderr are correctly set at the beginning,
> then fd _can_ not be 2 (because you did not close it before).
> Or if you don't assume that and you should check for that case (which,
> due to "open" being required to return the smallest non-open
> descriptor, my < 3 test does, though I admit it is not ideal
> in clearness).

I assume stdout is correctly set, does not assume whether stdin and
stderr are correctly set.
So my last code will works fine with the assume -- stdout is correctly set.
That's enough for current implement since it only care the stdout.


-- 
Ulion