From: "John P. Linderman" <jpl.jpl@gmail.com>
To: Warner Losh <imp@bsdimp.com>
Cc: The Unix Heritage Society <tuhs@minnie.tuhs.org>
Subject: Re: [TUHS] Command line options and complexity
Date: Thu, 12 Mar 2020 08:57:09 -0400 [thread overview]
Message-ID: <CAC0cEp_fQsq6-EaG-nhvXTvZij+PSab5PNTEx7WhNjYwnFVnaw@mail.gmail.com> (raw)
In-Reply-To: <CANCZdfp7=ZuS+enkrCa1zxBDhE-hAbKXFaiHkV_vTAe8tqGNYA@mail.gmail.com>
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My error. I was looking at getopt(1) rather than getopt(3). Of course
optind is documented, it's the way to find non-flag arguments.
I don't know why the Hancock authors chose to make rsort into a subroutine
rather than just piping into the command. Perhaps something to do with the
software release process?
On Wed, Mar 11, 2020 at 5:29 PM Warner Losh <imp@bsdimp.com> wrote:
>
>
> On Wed, Mar 11, 2020 at 11:43 AM John P. Linderman <jpl.jpl@gmail.com>
> wrote:
>
>> This is *great*, Kurt. The source in src/runtime/hrs/src for rsort.c is
>> their version of my external sort, modified to be a subroutine. There's
>> some lessons to be learned about "software hygiene". I was cavalier about
>> freeing what I allocated dynamically. As a result, their version leaks like
>> a sieve if the subroutine is called repeatedly. Apropos of which, they came
>> to me having noted that only the first call was acting as expected. There's
>> a wonderful irony (I'm big on irony). I had replaced my do-it-yourself
>> argument processing with getopt. The code has the following comment
>>
>> ** Use getopt() for portability.
>>
>> A few lines later, you see
>>
>> optind = 1; /* reset after use in Hancock program *
>> while ((c = getopt(argc, argv, "cCiIjmrsSuvb:f:D:o:p:T:x:y:z:")) !=
>> EOF) {
>>
>> optind??? Seems getopt has an undocumented global flag to prevent
>> reprocessing the arguments. How portable:-)
>>
>
> It's documented:
>
> The variables opterr and optind are both initialized to 1. The optind
> variable may be set to another value before a set of calls to
> getopt() in
> order to skip over more or less argv entries.
>
> is what the FreeBSD man page has to say about it. So this just resets any
> scanning that had happened before this...
>
> Warner
>
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next prev parent reply other threads:[~2020-03-12 12:58 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 14:06 Nelson H. F. Beebe
2020-03-04 16:17 ` John P. Linderman
2020-03-04 17:25 ` Bakul Shah
2020-03-05 0:55 ` Rob Pike
2020-03-05 2:05 ` Kurt H Maier
2020-03-05 4:17 ` Ken Thompson via TUHS
2020-03-05 14:53 ` Dan Cross
2020-03-05 21:50 ` Dave Horsfall
2020-03-05 21:56 ` Warner Losh
2020-03-08 5:26 ` Greg 'groggy' Lehey
2020-03-08 5:32 ` Jon Steinhart
2020-03-08 9:30 ` Tyler Adams
[not found] ` <CAC0cEp8eFRkkLTw88WVaKZoKy+qsrhuC8LkzmmsbqtdZgMf8eQ@mail.gmail.com>
[not found] ` <CAEuQd1D7+dfap98AwPo2W41+06prrcVaAWk3Ve-ve0uQ0xBu3Q@mail.gmail.com>
2020-03-09 21:06 ` John P. Linderman
2020-03-09 21:22 ` Kurt H Maier
2020-03-11 17:41 ` John P. Linderman
2020-03-11 21:29 ` Warner Losh
2020-03-12 0:13 ` John P. Linderman
2020-03-12 0:34 ` Chet Ramey
2020-03-12 12:57 ` John P. Linderman [this message]
2020-03-12 19:24 ` Steffen Nurpmeso
2020-03-08 9:51 ` Michael Kjörling
-- strict thread matches above, loose matches on Subject: below --
2020-03-13 10:45 Dave Horsfall
2020-03-14 4:35 ` Greg 'groggy' Lehey
2020-03-14 19:52 ` John P. Linderman
2020-03-14 20:25 ` Steffen Nurpmeso
2020-03-10 18:42 Doug McIlroy
2020-03-10 19:38 ` Dan Cross
2020-03-10 16:15 Doug McIlroy
2020-03-10 17:38 ` Dan Cross
2020-03-10 17:44 ` Bakul Shah
2020-03-10 18:09 ` Dan Cross
2020-03-05 4:57 Doug McIlroy
2020-03-05 22:17 ` Diomidis Spinellis
2020-03-03 18:15 Jon Steinhart
2020-03-03 18:44 ` Adam Thornton
2020-03-04 4:11 ` Tyler Adams
2020-03-04 6:03 ` Dave Horsfall
2020-03-04 6:48 ` arnold
2020-03-04 21:17 ` Dave Horsfall
2020-03-05 0:49 ` Lyndon Nerenberg
2020-03-05 20:54 ` Dave Horsfall
2020-03-05 22:01 ` William Cheswick
2020-03-04 21:50 ` Random832
2020-03-04 23:19 ` Steffen Nurpmeso
2020-03-05 6:12 ` Alan D. Salewski
2020-03-04 22:03 ` Random832
2020-03-04 23:25 ` Terry Jones
2020-03-10 23:03 ` Dan Stromberg
2020-03-11 3:18 ` Dave Horsfall
2020-03-11 4:02 ` Steve Nickolas
2020-03-11 22:56 ` Greg 'groggy' Lehey
2020-03-11 23:14 ` Dan Cross
2020-03-12 0:42 ` Greg 'groggy' Lehey
2020-03-12 0:53 ` Steve Nickolas
2020-03-12 3:09 ` Greg 'groggy' Lehey
2020-03-12 3:34 ` Steve Nickolas
2020-03-13 1:02 ` Greg 'groggy' Lehey
2020-03-12 5:38 ` Dave Horsfall
2020-03-12 6:48 ` Peter Jeremy
2020-03-12 7:37 ` Steve Nickolas
2020-03-12 7:42 ` Warner Losh
2020-03-12 23:57 ` Greg 'groggy' Lehey
2020-03-12 5:22 ` Dave Horsfall
2020-03-12 5:35 ` Steve Nickolas
2020-03-13 0:36 ` Greg 'groggy' Lehey
2020-03-13 11:26 ` Dave Horsfall
2020-03-14 2:13 ` Greg A. Woods
2020-03-14 4:31 ` Greg 'groggy' Lehey
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