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Groups > comp.lang.c > #127004
| From | Keith Thompson <kst-u@mib.org> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Text Files |
| Date | 2018-02-23 16:46 -0800 |
| Organization | None to speak of |
| Message-ID | <lny3jjjjua.fsf@kst-u.example.com> (permalink) |
| References | (9 earlier) <kfn371uw5ss.fsf@x-alumni2.alumni.caltech.edu> <ef3s8dtcrls5i26crkdklj3856b7ngpdsq@4ax.com> <kfnlgflvazg.fsf@x-alumni2.alumni.caltech.edu> <6flv8d9ii03eh280a1l8sia5a1eul0bsjs@4ax.com> <e8333d92-3eb3-4463-9720-725948c427ae@googlegroups.com> |
supercat@casperkitty.com writes:
> On Friday, February 23, 2018 at 3:08:25 AM UTC-6, robert...@yahoo.com wrote:
>> One example is inputting an integral value. Behavior on overflow is
>> undefined. So passing 9999999999 to sscanf %i (32 bit ints) might
>> result in 1.4 billion, INT_MAX, or something else. Using %lli doesn't
>> help, it just moves to boundary further out. You can specify a
>> maximum width and use a larger type in some cases.
>
> The problem is that there are a number of useful things that scanf could
> do in case of overflow, and none of them is sufficiently better than the
> others to justify mandating that all scanf implementations must be changed
> to do work that way. While the behavior should arguably be Implementation-
> Defined rather than Undefined, the only difference between Undefined
> Behavior and Implementation-Defined behavior in 1989 was whether
> implementations were *required* to formally document the behavior. Unless
> the Standard were to identify all the ways in which a scanf implementation
> might behave in case of overflow, UB and IDB would have been the same from
> a portability standpoint.
Of course the standard would specify all the ways it might behave.
Implementation-defined behavior is by definition
unspecified behavior where each implementation documents how the
choice is made
and unspecified behavior is
use of an unspecified value, or other behavior where this
International Standard **provides two or more possibilities**
and imposes no further requirements on which is chosen in
any instance
(emphasis added).
Reasonable behaviors could include setting the object to an
unspecified or implementation-defined value, or treating overflow as
a matching failure. If the standard were changed to require overflow
to behave in one of those ways, it might not break any existing
implementations, but it would make the *scanf functions much safer.
As it is, `sscanf("999999999999", "%d", &n)` could crash your
program. If overflow were implementation-defined rather than UB,
it couldn't.
--
Keith Thompson (The_Other_Keith) kst-u@mib.org <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"
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Text Files G B <gb@gb.com> - 2018-02-14 11:47 -0400
Re: Text Files Ed Prochak <edprochak@gmail.com> - 2018-02-14 08:45 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-14 08:47 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-15 01:17 -0800
Re: Text Files gordonb.ea2mq@burditt.org (Gordon Burditt) - 2018-02-14 11:10 -0600
Re: Text Files "James R. Kuyper" <jameskuyper@verizon.net> - 2018-02-14 12:28 -0500
Re: Text Files jt@toerring.de (Jens Thoms Toerring) - 2018-02-14 21:07 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-14 15:31 -0700
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-15 06:59 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 10:20 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-14 22:51 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 11:04 +0100
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-15 06:16 -0800
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-15 22:22 +0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 15:58 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 16:31 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 21:31 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 21:21 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 22:17 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 23:36 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:48 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:09 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 12:57 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 15:50 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 15:50 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 17:07 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 20:44 +0000
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 11:22 +1300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 17:48 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-16 17:06 +0100
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 11:10 +1300
Re: Text Files supercat@casperkitty.com - 2018-02-16 14:48 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-16 15:14 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 23:25 +0000
Re: Text Files supercat@casperkitty.com - 2018-02-16 15:50 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-16 07:19 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 17:13 +0100
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-19 17:55 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-19 19:14 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-19 11:48 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 08:14 -0800
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-17 18:32 -0600
Re: Text Files jacobnavia <jacob@jacob.remcomp.fr> - 2018-02-15 22:57 +0100
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 22:58 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 00:19 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 02:26 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 02:57 +0000
Re: Text Files asetofsymbols@gmail.com - 2018-02-16 00:21 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 11:30 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:36 +0100
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 11:36 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 13:10 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 12:25 +0000
Re: Text Files Ike Naar <ike@iceland.freeshell.org> - 2018-03-06 19:33 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-03-06 20:55 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 04:42 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 16:58 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 20:02 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 21:43 +0100
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 04:01 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 13:10 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 05:27 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 14:20 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-16 09:04 -0700
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 14:31 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 06:42 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-16 14:58 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 07:23 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-16 15:24 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-16 04:13 -0800
Re: Text Files Siri Cruise <chine.bleu@yahoo.com> - 2018-02-16 04:29 -0800
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-20 16:41 +0000
Re: Text Files Siri Cruise <chine.bleu@yahoo.com> - 2018-02-20 09:39 -0800
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-20 19:16 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 12:46 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-15 14:52 +0100
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-15 17:07 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 14:23 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-15 18:52 +0300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 14:39 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 15:43 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 20:32 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 22:06 +0000
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-15 23:12 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-15 15:12 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 23:43 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:54 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 23:35 +0000
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-16 17:07 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-17 02:38 +0000
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-17 17:26 +1300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-17 11:22 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-17 12:07 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 04:17 -0800
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-17 16:25 +0300
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-17 07:35 -0800
Re: Text Files GOTHIER Nathan <nathan.gothier@gmail.com> - 2018-02-17 15:24 +0100
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-18 11:10 +1300
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-19 12:05 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-19 15:32 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-21 10:34 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-21 15:35 -0800
Re: Text Files bartc <bc@freeuk.com> - 2018-02-22 00:11 +0000
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-21 18:26 -0600
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-21 21:39 -0800
Re: Text Files Robert Wessel <robertwessel2@yahoo.com> - 2018-02-23 03:08 -0600
Re: Text Files supercat@casperkitty.com - 2018-02-23 16:16 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-23 16:46 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-24 02:49 -0800
Re: Text Files asetofsymbols@gmail.com - 2018-02-24 05:16 -0800
Re: Text Files "F. Russell" <fr@random.info> - 2018-02-24 14:35 +0000
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-24 08:48 -0700
Re: Text Files supercat@casperkitty.com - 2018-02-25 15:09 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-25 15:54 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-26 11:04 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 11:52 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-26 14:12 -0800
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 14:40 -0800
Re: Text Files already5chosen@yahoo.com - 2018-02-22 04:58 -0800
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-22 05:33 -0800
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-22 13:59 +0000
Re: Text Files Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-02-22 07:24 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-20 12:14 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-15 21:37 +0100
Re: Text Files bartc <bc@freeuk.com> - 2018-02-15 21:34 +0000
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-15 14:15 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-16 10:47 +0100
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-15 22:20 +0800
Re: Text Files "F. Russell" <fr@random.info> - 2018-02-15 15:24 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-15 16:05 +0000
Re: Text Files "Mr. Man-wai Chang" <toylet.toylet@gmail.com> - 2018-02-16 00:22 +0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-15 13:35 -0700
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 00:13 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-24 21:24 +0000
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 14:55 +0300
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 13:00 +0000
Re: Text Files Real Troll <Real.Troll@Trolls.com> - 2018-02-24 17:35 -0400
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-24 21:36 +0000
Re: Text Files Real Troll <Real.Troll@Trolls.com> - 2018-02-24 17:45 -0400
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-24 22:51 +0000
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-24 23:56 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 00:14 +0000
Re: Text Files bartc <bc@freeuk.com> - 2018-02-25 00:22 +0000
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 15:16 +0300
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-25 15:20 -0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-25 20:27 -0700
Re: Text Files gazelle@shell.xmission.com (Kenny McCormack) - 2018-02-26 06:19 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-26 15:35 +0300
Re: Text Files Reinhardt Behm <rbehm@hushmail.com> - 2018-02-26 20:53 +0800
Grammar Patrol (Was: Text Files) gazelle@shell.xmission.com (Kenny McCormack) - 2018-02-26 17:54 +0000
Re: Text Files Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-02-26 15:27 +0000
Re: Text Files Anton Shepelev <anton.txt@g{oogle}mail.com> - 2018-02-26 18:50 +0300
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 09:26 -0800
Re: Text Files scott@slp53.sl.home (Scott Lurndal) - 2018-02-26 19:46 +0000
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 09:04 +0100
Re: Text Files already5chosen@yahoo.com - 2018-02-27 00:56 -0800
Re: Text Files Ian Collins <ian-news@hotmail.com> - 2018-02-27 22:07 +1300
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 14:37 +0100
Re: Text Files already5chosen@yahoo.com - 2018-02-27 07:38 -0800
Re: Text Files supercat@casperkitty.com - 2018-02-27 09:18 -0800
Re: Text Files David Brown <david.brown@hesbynett.no> - 2018-02-27 10:15 +0100
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-27 08:53 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-26 23:14 -0800
Re: Text Files Joe Pfeiffer <pfeiffer@cs.nmsu.edu> - 2018-02-26 08:32 -0700
Re: Text Files Keith Thompson <kst-u@mib.org> - 2018-02-26 09:17 -0800
Re: Text Files Tim Rentsch <txr@alumni.caltech.edu> - 2018-02-26 22:55 -0800
Re: Text Files Anton Shepelev <anton.txt@gmail.com> - 2018-02-25 15:02 +0300
Re: Text Files Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-02-25 20:12 +0000
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