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From: Peter Pentchev <roam@ringlet.net>
To: Warner Losh <imp@bsdimp.com>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: Re: [TUHS] v7 K&R C
Date: Tue, 19 May 2020 22:45:34 +0300	[thread overview]
Message-ID: <20200519194534.GH140052@straylight.m.ringlet.net> (raw)
In-Reply-To: <CANCZdfrpUJ4iPQ9b0=dowOPat0eupG_Z2vHLfp1=6At7Pgp6Uw@mail.gmail.com>

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On Sat, May 16, 2020 at 11:39:54AM -0600, Warner Losh wrote:
> On Sat, May 16, 2020 at 10:28 AM Paul Winalski <paul.winalski@gmail.com>
> wrote:
> 
> > > On Fri, May 15, 2020 at 4:02 PM <ron@ronnatalie.com> wrote:
> > >
> > >Unfortunately, if c is char on a machine with unsigned chars, or it’s of
> > >type unsigned char, the EOF will never be detected.
> > >
> > >    - while ((c = getchar()) != EOF) if (c == '\n') { /* entire record is
> > now there */
> >
> > The function prototype for getchar() is:    int getchar(void);
> >
> > It returns an int, not a char.  In all likelihood this is specifically
> > *because* EOF is defined as -1.  The above code works fine if c is an
> > int.  One always has to be very careful when doing a typecast of a
> > function return value.
> >
> 
> In the early days of my involvement with FreeBSD, I went through and fixed
> about a dozen cases where getopt was being assigned to a char and then
> compared with EOF. I'm certain that this is why. Also EOF has to be a value
> that's not representable by a character, or your 0xff bytes would disappear.

I think I remember a code review on one of my patches to du(1), I think,
something about adding an option to ignore specific names when
recursing, and I remember either you or BDE chastising me about
while (ch = getopt(...), ch != EOF) :)

G'luck,
Peter

-- 
Peter Pentchev  roam@ringlet.net roam@debian.org pp@storpool.com
PGP key:        http://people.FreeBSD.org/~roam/roam.key.asc
Key fingerprint 2EE7 A7A5 17FC 124C F115  C354 651E EFB0 2527 DF13

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  reply	other threads:[~2020-05-19 19:53 UTC|newest]

Thread overview: 139+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-14 18:41 Doug McIlroy
2020-05-14 18:45 ` Richard Salz
2020-05-14 20:54 ` Clem Cole
2020-05-15  2:44 ` Rob Pike
2020-05-15  3:57   ` Rich Morin
2020-05-15  7:55   ` Dr Iain Maoileoin
2020-05-15 15:01     ` Larry McVoy
2020-05-15 15:36       ` John P. Linderman
2020-05-15 20:01         ` ron
2020-05-15 20:03           ` Larry McVoy
2020-05-15 20:05           ` Clem Cole
2020-05-15 20:18             ` ron
2020-05-15 20:24               ` Clem Cole
2020-05-16  0:57               ` Brantley Coile
2020-05-16 16:14                 ` Dan Cross
2020-05-15 20:56           ` Steve Nickolas
2020-05-16  0:31             ` Peter Jeremy
2020-05-16  8:30               ` Steve Nickolas
2020-05-16  0:43           ` John P. Linderman
2020-05-16 16:28             ` Paul Winalski
2020-05-16 17:39               ` Warner Losh
2020-05-19 19:45                 ` Peter Pentchev [this message]
2020-05-20  3:52                   ` Rich Morin
2020-05-21 15:06                     ` Dave Horsfall
  -- strict thread matches above, loose matches on Subject: below --
2020-05-19 12:29 Noel Chiappa
2020-05-19  2:29 Doug McIlroy
2020-05-19  3:20 ` Steve Nickolas
2020-05-18 14:33 Doug McIlroy
2020-05-18 13:58 Doug McIlroy
2020-05-16 18:45 Richard Tobin
2020-05-16 21:55 ` Ronald Natalie
2020-05-16  0:15 Nelson H. F. Beebe
2020-05-16  0:28 ` Steffen Nurpmeso
2020-05-16  1:52 ` Warner Losh
2020-05-16 16:31   ` Paul Winalski
2020-05-16 20:35     ` Brad Spencer
2020-05-16 20:37       ` Warner Losh
2020-05-18 12:25     ` Tony Finch
2020-05-15 21:31 Richard Tobin
2020-05-15 21:53 ` Steve Nickolas
2020-05-15 22:33   ` ron
2020-05-15 23:34     ` Steffen Nurpmeso
2020-05-16  1:26       ` Larry McVoy
2020-05-16 21:59       ` Ronald Natalie
2020-05-16 23:26         ` Steffen Nurpmeso
2020-05-17 16:24           ` Paul Winalski
2020-05-17 16:29             ` ron
2020-05-17 16:38               ` Paul Winalski
2020-05-17 20:08                 ` Clem Cole
2020-05-18  8:46                   ` Peter Jeremy
2020-05-19  7:41                     ` Dave Horsfall
2020-05-18 12:04             ` Tony Finch
2020-05-18 13:10               ` Clem Cole
2020-05-18 15:13             ` Rich Morin
2020-05-18 15:51               ` Brantley Coile
2020-05-18 16:11             ` Dan Cross
2020-05-18 21:18               ` ron
2020-05-17 16:10 ` Derek Fawcus
2020-05-17 16:14   ` ron
2020-05-15 20:34 Doug McIlroy
2020-05-15 20:40 ` Warner Losh
     [not found] <mailman.1.1589421601.13778.tuhs@minnie.tuhs.org>
2020-05-14  3:02 ` Paul McJones
2020-05-14 17:08   ` Paul Winalski
2020-05-14 17:58     ` Clem Cole
2020-04-27 17:45 Noel Chiappa
2020-04-27 17:56 ` Richard Salz
2020-04-27 18:02 ` Brantley Coile
2020-04-27 18:47 ` Derek Fawcus
2020-04-25 19:41 Noel Chiappa
2020-04-25 20:27 ` Steffen Nurpmeso
2020-04-25 13:11 Noel Chiappa
2020-04-25 13:18 ` Rob Pike
2020-04-25 14:57   ` Warner Losh
2020-04-25 18:03   ` Noel Chiappa
2020-04-25 20:11     ` Michael Kjörling
2020-04-25 21:27       ` Brian L. Stuart
2020-04-26  0:07     ` emanuel stiebler
2020-04-26  0:54     ` Rob Pike
2020-04-26 19:37     ` Derek Fawcus
2020-04-26 20:10       ` Derek Fawcus
2020-04-26 21:59         ` Rich Morin
2020-04-26 22:38         ` Noel Hunt
2020-04-26 23:57         ` Nemo Nusquam
2020-04-27  3:38           ` Rob Pike
2020-04-25 13:35 ` Hellwig Geisse
2020-04-25 13:59   ` Richard Salz
2020-04-25 19:01   ` Brian L. Stuart
2020-04-25 20:07     ` Michael Kjörling
2020-04-25 21:34       ` Brian L. Stuart
2020-04-26  6:40     ` arnold
2020-04-25  1:59 Adam Thornton
2020-04-25  2:37 ` Charles Anthony
2020-04-25  2:47   ` Adam Thornton
2020-04-25  2:51     ` Rob Pike
2020-04-25  2:54       ` Rob Pike
2020-04-25  3:04         ` Larry McVoy
2020-04-25  3:30           ` Clem Cole
2020-04-25  3:43             ` Larry McVoy
2020-04-25  3:54               ` Jon Steinhart
2020-04-25 11:44                 ` Michael Kjörling
2020-04-25 13:17             ` Dan Cross
2020-05-11  0:28         ` scj
2020-05-11  0:32           ` Rob Pike
2020-05-11  0:57             ` Larry McVoy
2020-05-11 17:32               ` Greg A. Woods
2020-05-11 18:25                 ` Paul Winalski
2020-05-11 18:37                   ` Clem Cole
2020-05-11 19:12                     ` Paul Winalski
2020-05-11 19:57                       ` joe mcguckin
2020-05-11 20:25                         ` Larry McVoy
2020-05-12 17:23                           ` Paul Winalski
2020-05-12 17:35                             ` ron
2020-05-12 17:42                               ` Larry McVoy
2020-05-12 18:36                               ` Paul Winalski
2020-05-13 23:36                             ` Dave Horsfall
2020-05-14  0:42                               ` John P. Linderman
2020-05-14  2:44                                 ` Rich Morin
2020-05-14  3:09                                   ` Charles Anthony
2020-05-14 12:27                                     ` ron
2020-05-14 12:27                                     ` ron
2020-05-14 12:27                                     ` ron
2020-05-14  7:38                                   ` Dave Horsfall
2020-05-14 12:25                                     ` ron
2020-05-14 17:13                                   ` Paul Winalski
2020-05-14 17:21                                 ` Larry McVoy
2020-05-17 16:34                                   ` Derek Fawcus
2020-05-14  4:21                               ` Greg A. Woods
2020-05-14  4:40                                 ` Warner Losh
2020-05-14 17:32                               ` Larry McVoy
2020-05-14 22:32                                 ` Tony Finch
2020-05-16 23:53                                   ` Steffen Nurpmeso
2020-05-17  0:35                                     ` Larry McVoy
2020-05-11 18:37                   ` Larry McVoy
2020-05-11  2:08           ` Lawrence Stewart
2020-05-11 11:36           ` Michael Kjörling
2020-04-25  3:37       ` Dave Horsfall
2020-04-27 13:19       ` Tony Finch
2020-04-25  2:50   ` Adam Thornton
2020-04-25  5:59     ` Lars Brinkhoff

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