Re: getline() problem

From	Vir Campestris <vir.campestris@invalid.invalid>
Newsgroups	comp.lang.c++
Subject	Re: getline() problem
Date	2022-04-25 16:54 +0100
Organization	A noiseless patient Spider
Message-ID	<t46g6s$3e7$1@dont-email.me> (permalink)
References	(2 earlier) <t41dmo$35p5k$1@portraits.wsisiz.edu.pl> <t41er4$35r34$1@portraits.wsisiz.edu.pl> <t41hkn$6p9$1@dont-email.me> <t45de2$1sln$2@gioia.aioe.org> <t46f86$or8$1@dont-email.me>

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On 25/04/2022 16:37, James Kuyper wrote:
> On 4/25/22 02:00, Juha Nieminen wrote:
>> Paavo Helde <eesnimi@osa.pri.ee> wrote:
>>> There is no problem with reading NUL bytes in C++, they are not handled
>>> specially in any way, unlike in C.
>>
>> Still, I wonder if the file stream should be opened in binary mode
>> (instead of the default). I have experiences of this making a difference
>> with the Microsoft compilers in Windows. It can do funky things to
>> binary input if the file stream isn't opened in binary mode.
> 
> The C++ standard says very little about the differences between text
> mode and binary mode, cross-referencing the C standard for such issues.
> The C standard says something important to this issue:
> 
> "... Data read in from a text stream will necessarily compare equal to
> the data that were earlier written out to that stream only if: the data
> consist only of printing characters and the control characters
> horizontal tab and new-line; no new-line character is immediately
> preceded by space characters; and the last character is a new-line
> character. ..." (7.21.2p2).
> 
> As a general rule, you should not write data to a text stream if it
> contains any feature invalidating that guarantee, and you should not
> read data from a text stream if it contains any of those things.

Windows text files have 13,10 as a newline sequence, not just 10 as in 
Linux etc.

This dates back to at least CP/M where the byte stream in the file 
exactly matched the one you would send to your CRT or printer, and a 
line feed really did move the roller but not the print head.

I have a vague feeling that Apple might use 10,13 - certainly I've met 
it somewhere in the past.

The point of text mode is to allow a program to ignore these differences 
by allowing the runtime to handle them.

It's not 100%.

Andy

Thread

getline() problem Jivanmukta <jivanmukta@poczta.onet.pl> - 2022-04-23 19:07 +0200
  Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-23 10:17 -0700
    Re: getline() problem Jivanmukta <jivanmukta@poczta.onet.pl> - 2022-04-23 19:40 +0200
      Re: getline() problem Jivanmukta <jivanmukta@poczta.onet.pl> - 2022-04-23 19:59 +0200
        Re: getline() problem Paavo Helde <eesnimi@osa.pri.ee> - 2022-04-23 21:47 +0300
          Re: getline() problem Juha Nieminen <nospam@thanks.invalid> - 2022-04-25 06:00 +0000
            Re: getline() problem Öö Tiib <ootiib@hot.ee> - 2022-04-25 00:12 -0700
            Re: getline() problem Paavo Helde <eesnimi@osa.pri.ee> - 2022-04-25 11:40 +0300
            Re: getline() problem James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-04-25 11:37 -0400
              Re: getline() problem Vir Campestris <vir.campestris@invalid.invalid> - 2022-04-25 16:54 +0100
                Re: getline() problem James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-04-25 12:29 -0400
                Re: getline() problem scott@slp53.sl.home (Scott Lurndal) - 2022-04-25 17:29 +0000
                Re: getline() problem Manfred <noname@add.invalid> - 2022-04-25 20:17 +0200
                Re: getline() problem Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-04-25 10:19 -0700
                Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-25 10:41 -0700
                Re: getline() problem Paavo Helde <eesnimi@osa.pri.ee> - 2022-04-25 21:58 +0300
              Re: getline() problem scott@slp53.sl.home (Scott Lurndal) - 2022-04-25 15:56 +0000
                Re: getline() problem James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-04-25 13:12 -0400
                Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-25 11:03 -0700
                Re: getline() problem scott@slp53.sl.home (Scott Lurndal) - 2022-04-25 19:05 +0000
                Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-25 12:48 -0700
                Re: getline() problem Ben <ben.usenet@bsb.me.uk> - 2022-04-25 21:46 +0100
                Re: getline() problem Juha Nieminen <nospam@thanks.invalid> - 2022-04-26 05:43 +0000
                Re: getline() problem David Brown <david.brown@hesbynett.no> - 2022-04-26 09:36 +0200
                Re: getline() problem Juha Nieminen <nospam@thanks.invalid> - 2022-04-26 09:18 +0000
                Re: getline() problem Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-04-26 02:47 -0700
                Re: getline() problem Juha Nieminen <nospam@thanks.invalid> - 2022-04-26 11:06 +0000
                Re: getline() problem David Brown <david.brown@hesbynett.no> - 2022-04-26 15:52 +0200
                Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-26 07:04 -0700
                Re: getline() problem Manfred <noname@add.invalid> - 2022-04-26 16:49 +0200
                Re: getline() problem James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-04-26 12:01 -0400
                Re: getline() problem James Kuyper <jameskuyper@alumni.caltech.edu> - 2022-04-26 11:49 -0400
                Re: getline() problem Manfred <noname@add.invalid> - 2022-04-25 20:23 +0200
            Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-25 10:33 -0700
              Re: getline() problem "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2022-04-25 10:52 -0700
                Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-25 11:08 -0700
                Re: getline() problem "james...@alumni.caltech.edu" <jameskuyper@alumni.caltech.edu> - 2022-04-25 21:18 -0700
                Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-25 22:04 -0700
              Re: getline() problem Paavo Helde <eesnimi@osa.pri.ee> - 2022-04-25 22:06 +0300
                Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-25 13:02 -0700
        Re: getline() problem Barry Schwarz <schwarzb@delq.com> - 2022-04-23 12:54 -0700
        Re: getline() problem Montmorency <none@none.com> - 2022-04-23 14:45 -0700
          Re: getline() problem Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-04-23 16:49 -0700
            Re: getline() problem Ben <ben.usenet@bsb.me.uk> - 2022-04-24 01:04 +0100
              Re: getline() problem Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2022-04-23 18:24 -0700
                Re: getline() problem Ben <ben.usenet@bsb.me.uk> - 2022-04-24 03:16 +0100
                Re: getline() problem Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2022-04-24 22:51 -0700
                Re: getline() problem Ben <ben.usenet@bsb.me.uk> - 2022-04-25 11:07 +0100
            Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-23 17:15 -0700
              Re: getline() problem Andrey Tarasevich <andreytarasevich@hotmail.com> - 2022-04-23 18:23 -0700
          Re: getline() problem Jivanmukta <jivanmukta@poczta.onet.pl> - 2022-04-24 05:28 +0200
  Re: getline() problem Jivanmukta <jivanmukta@poczta.onet.pl> - 2022-04-25 12:41 +0200
    Re: getline() problem Paavo Helde <eesnimi@osa.pri.ee> - 2022-04-25 14:33 +0300
    Re: getline() problem Jivanmukta <jivanmukta@poczta.onet.pl> - 2022-04-25 18:53 +0200
      Re: getline() problem Paavo Helde <eesnimi@osa.pri.ee> - 2022-04-25 22:08 +0300
        Re: getline() problem Jivanmukta <jivanmukta@poczta.onet.pl> - 2022-04-26 09:01 +0200
          Re: getline() problem Paavo Helde <eesnimi@osa.pri.ee> - 2022-04-26 11:15 +0300

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