From: Harald van Dijk <harald@gigawatt.nl>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: martijn@inlv.org, dash@vger.kernel.org
Subject: Re: getopts doesn't properly update OPTIND when called from function
Date: Fri, 29 May 2015 07:50:09 +0200 [thread overview]
Message-ID: <5567FE11.8060103@gigawatt.nl> (raw)
In-Reply-To: <20150529025809.GA16240@gondor.apana.org.au>
On 29/05/2015 04:58, Herbert Xu wrote:
> Harald van Dijk <harald@gigawatt.nl> wrote:
>> That isn't the problem, not exactly anyway. The problem is that getopts
>> is required to keep internal state separately from the OPTIND variable
>> (a single integer is insufficient to track the progress when multiple
>> options are combined in a single word), and that internal state is
>> stored along with the positional parameters. The positional parameters
>> are saved just before a function call, and restored when the function
>> returns. The internal state of getopts should not be saved the same way.
>> It should probably just be global to dash.
>
> I think the current behaviour is fine as far as POSIX is concerned.
> It says:
>
> http://pubs.opengroup.org/onlinepubs/9699919799/utilities/getopts.html
>
> : APPLICATION USAGE
>
> ...
>
> : Note that shell functions share OPTIND with the calling shell
> : even though the positional parameters are changed. If the calling
> : shell and any of its functions uses getopts to parse arguments,
> : the results are unspecified.
The Application usage sections are informative and aren't worded as
precisely as the other sections. If a script uses getopts at the global
level, and it calls a shell function that too uses getopts, then it is
very easy to be covered by
> Any other attempt to invoke getopts multiple times in a single shell
execution environment with parameters (positional parameters or arg
operands) that are not the same in all invocations, or with an OPTIND
value modified to be a value other than 1, produces unspecified results.
But the test script in this thread does invoke getopts with parameters
that are the same in all invocations, and without modifying OPTIND. I
don't see anything else in the normative sections that would make the
result undefined or unspecified either. I do think the script is valid,
and the results in dash should match those of other shells.
Cheers,
Harald van Dijk
next prev parent reply other threads:[~2015-05-29 5:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-28 18:54 getopts doesn't properly update OPTIND when called from function Martijn Dekker
2015-05-28 22:39 ` Harald van Dijk
2015-05-29 2:58 ` Herbert Xu
2015-05-29 5:50 ` Harald van Dijk [this message]
2015-06-01 6:29 ` Herbert Xu
2015-06-01 17:30 ` Harald van Dijk
2015-06-01 22:10 ` Jilles Tjoelker
2015-06-02 0:21 ` Harald van Dijk
2015-06-04 19:56 ` Martijn Dekker
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