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

[Eric Blake <eblake@redhat.com>]

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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.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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