Re: [Qemu-block] [PATCH v2] qemu-io: Reinitialize optind to 1 (not 0) before parsing inner command.

[Kevin Wolf]

Am 08.01.2019 um 15:51 hat Eric Blake geschrieben:
> On 1/8/19 6:16 AM, Kevin Wolf wrote:
> > Unconditionally setting optind = 1 looks fine. I would, however, quote a
> > different part of the glibc man page (in addition or instead of the
> > paragraph you already quoted):
> > 
> >     The  variable  optind is the index of the next element to be
> >     processed in argv.  The system initializes this value to 1.  The
> >     caller can reset it to 1 to restart scanning of the same argv, or
> >     when scanning a new argument vector.
> > 
> > This makes it pretty clear that optind = 1 is fine for our case with
> > glibc. The FreeBSD man page still suggests that we need optreset = 1, so
> > I suppose we'd end up with something like:
> > 
> > ...
> > optind = 1;
> > #ifdef __FreeBSD__
> > optreset = 1;
> > #endif
> 
> If you really want to set optreset for BSD systems, I'd do a configure
> probe for whether optreset exists, and if so set it for ALL platforms
> that have optreset, not just for __FreeBSD__.  (That, and checkpatch.pl
> will gripe if you don't do it that way).
> 
> But I'm leaning towards not bothering with optreset UNLESS someone
> proves they have a case where it actually matters.

I don't mind either way as long as it works. Using optreset would be
following the spec by the letter.

In fact, I had already applied this patch because it's correct even if
possibly incomplete, depending on your interpretation, but I decided to
reply instead because the commit message didn't really describe that
optreset = 1 is correct for glibc, but that optreset = 0 is necessary in
some other case (which is irrelevant here). So the commit message was my
main point.

Kevin

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