Re: How to write wide char string literals?

From	"Alf P. Steinbach" <alf.p.steinbach@gmail.com>
Newsgroups	comp.lang.c++
Subject	Re: How to write wide char string literals?
Date	2021-07-03 16:28 +0200
Organization	A noiseless patient Spider
Message-ID	<sbps5k$b5m$1@dont-email.me> (permalink)
References	(9 earlier) <sbns4s$cfd$1@dont-email.me> <sboej7$scd$1@dont-email.me> <sbopvo$qt9$1@dont-email.me> <sbphpm$vh9$1@dont-email.me> <sbpm41$thv$1@dont-email.me>

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On 3 Jul 2021 14:44, James Kuyper wrote:
> On 7/3/21 7:31 AM, Alf P. Steinbach wrote:
>> On 3 Jul 2021 06:44, James Kuyper wrote:
[snippety]
>>>
>>> UTF-8: u8"\u00A9\U000000A9"
>>> UTF-16: u"\251\xA9\u00A9\U000000A9"
>>> UTF-32: U"\251\xA9\u00A9\U000000A9"
>>>
>>> Do you know of any implementation which is non-conforming because it
>>> misinterprets any of those escape sequences?
>>    No, they should work. These escapes are an alternative solution to
>> Juha's problem. ...
> 
> They are the only solution that this sub-thread has been about.
> 
>> ... However, they lack readability and involve much more
>> work than necessary, so IMO the thing to do is to assert UTF-8.
> 
> Those are reasonable concerns. That the system's assumptions about the
> source character set would prevent those escapes from working is not.

As far as I know nobody's argued that the source encoding assumption 
would prevent any escapes from working.

If I understand you correctly your “this sub-thread” about escapes and 
universal character designators  --  let's just call them all escapes 
-- started when you responded to my response Richard Daemon, who had 
responded to Juha Niemininen, who wrote:

[>>]
Does that work for wide string literals? Because I don't think it does.
In other words:

std::wstring s = L"Copyright \xC2\xA9 2001-2020";
[<<]

Richard responded to that:

[>>]
\x works in wide string literal too, and puts in a character with that
value. The difference is that if the wide string type isn't unicode
encoded then it might get the wrong character in the string.
[<<]

I responded to Richard:

[>>]
It gets the wrong characters in the wide string literal, period.
[<<]

Which it decidedly does.

It's trivial to just try it out and see; QED.

You responded to that where you snipped Juha's example, indicating some 
misunderstanding on your part:

[>>]
The value of a wide character is determined by the current encoding. For
wide character literals using the u or U prefixes, that encoding is
UTF-16 and UTF-32, respectively, making octal escapes redundant with and
less convenient than the use of UCNs. But as he said, they do work for
such strings.
[<<]

So, in your mind this sub-thread may have been about whether escape 
sequences (including universal character designators) are affected by 
the source encoding, but to me it has been about whether Juha's example 
yields the desired string, as he correctly surmised that it didn't.

And the outer context from the top thread, is about the source 
encoding's effect on string literals, which hopefully is now clear.

- Alf

Thread

How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-06-30 07:57 +0000
  Re: How to write wide char string literals? Kli-Kla-Klawitter <kliklaklawitter69@gmail.com> - 2021-06-30 10:05 +0200
    Re: How to write wide char string literals? Ralf Goertz <me@myprovider.invalid> - 2021-06-30 10:30 +0200
      Re: How to write wide char string literals? Kli-Kla-Klawitter <kliklaklawitter69@gmail.com> - 2021-06-30 12:37 +0200
        Re: How to write wide char string literals? Ralf Goertz <me@myprovider.invalid> - 2021-07-01 09:19 +0200
          Re: How to write wide char string literals? Kli-Kla-Klawitter <kliklaklawitter69@gmail.com> - 2021-07-01 11:10 +0200
            Re: How to write wide char string literals? Ralf Goertz <me@myprovider.invalid> - 2021-07-01 11:36 +0200
              Re: How to write wide char string literals? Kli-Kla-Klawitter <kliklaklawitter69@gmail.com> - 2021-07-01 16:17 +0200
                Re: How to write wide char string literals? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-07-01 10:13 -0700
                Re: How to write wide char string literals? Kli-Kla-Klawitter <kliklaklawitter69@gmail.com> - 2021-07-01 19:27 +0200
                Re: How to write wide char string literals? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-07-01 11:21 -0700
                Re: How to write wide char string literals? Real Troll <real.troll@trolls.com> - 2021-07-01 18:45 +0000
                Re: How to write wide char string literals? Kli-Kla-Klawitter <kliklaklawitter69@gmail.com> - 2021-07-02 10:03 +0200
              Re: How to write wide char string literals? Keith Thompson <Keith.S.Thompson+u@gmail.com> - 2021-07-02 02:31 -0700
                Re: How to write wide char string literals? MrSpud_oyCn@92wvlb1hltq4dhc.gov.uk - 2021-07-02 09:38 +0000
                Re: How to write wide char string literals? Paavo Helde <myfirstname@osa.pri.ee> - 2021-07-02 13:52 +0300
                Re: How to write wide char string literals? MrSpud_zg8yg@nx8574z6ey2rc0y563k5i2.net - 2021-07-02 12:53 +0000
                Re: How to write wide char string literals? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-07-02 15:22 +0200
                Re: How to write wide char string literals? Paavo Helde <myfirstname@osa.pri.ee> - 2021-07-02 17:32 +0300
  Re: How to write wide char string literals? Ralf Goertz <me@myprovider.invalid> - 2021-06-30 10:08 +0200
  Re: How to write wide char string literals? MrSpud_r5j@ywn9entw2s.org - 2021-06-30 08:39 +0000
    Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-06-30 10:52 +0000
      Re: How to write wide char string literals? MrSpud_3u59h8@0c9tv3nddl090w2ynhm.gov - 2021-06-30 11:28 +0000
        Re: How to write wide char string literals? David Brown <david.brown@hesbynett.no> - 2021-06-30 14:01 +0200
  Re: How to write wide char string literals? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-06-30 10:55 +0200
    Re: How to write wide char string literals? David Brown <david.brown@hesbynett.no> - 2021-06-30 11:23 +0200
  Re: How to write wide char string literals? Richard Damon <Richard@Damon-Family.org> - 2021-06-30 06:51 -0400
    Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-06-30 11:09 +0000
      Re: How to write wide char string literals? Richard Damon <Richard@Damon-Family.org> - 2021-06-30 07:35 -0400
  Re: How to write wide char string literals? Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-30 14:03 +0300
    Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-06-30 11:13 +0000
      Re: How to write wide char string literals? Richard Damon <Richard@Damon-Family.org> - 2021-06-30 07:39 -0400
        Re: How to write wide char string literals? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-06-30 13:50 +0200
          Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-06-30 14:19 -0400
            Re: How to write wide char string literals? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-07-01 13:31 +0200
        Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-01 04:42 +0000
          Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-01 10:58 -0400
            Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-02 05:26 +0000
              Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-02 01:44 -0400
                Re: How to write wide char string literals? Bo Persson <bo@bo-persson.se> - 2021-07-02 08:33 +0200
                Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-02 11:52 +0000
                Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-02 16:15 -0400
                Re: How to write wide char string literals? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-07-03 03:30 +0200
                Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-03 00:44 -0400
                Re: How to write wide char string literals? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-07-03 13:31 +0200
                Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-03 08:44 -0400
                Re: How to write wide char string literals? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-07-03 16:28 +0200
                Re: How to write wide char string literals? Richard Damon <Richard@Damon-Family.org> - 2021-07-03 11:48 -0400
                Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-08 15:56 -0400
                Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-03 16:59 +0000
                Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-03 17:49 -0400
                Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-08 08:11 +0000
                Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-08 05:52 -0400
                Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-03 06:59 +0000
                Re: How to write wide char string literals? James Kuyper <jameskuyper@alumni.caltech.edu> - 2021-07-03 09:03 -0400
                Re: How to write wide char string literals? Chris Vine <chris@cvine--nospam--.freeserve.co.uk> - 2021-07-03 14:23 +0100
                Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-03 17:06 +0000
                Re: How to write wide char string literals? Richard Damon <Richard@Damon-Family.org> - 2021-07-03 14:06 -0400
                Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-08 08:13 +0000
                Re: How to write wide char string literals? "Alf P. Steinbach" <alf.p.steinbach@gmail.com> - 2021-07-02 15:37 +0200
      Re: How to write wide char string literals? Manfred <noname@add.invalid> - 2021-06-30 16:54 +0200
      Re: How to write wide char string literals? Paavo Helde <myfirstname@osa.pri.ee> - 2021-06-30 17:56 +0300
  Re: How to write wide char string literals? Öö Tiib <ootiib@hot.ee> - 2021-06-30 09:22 -0700
  Re: How to write wide char string literals? Christian Gollwitzer <auriocus@gmx.de> - 2021-07-01 07:19 +0200
    Re: How to write wide char string literals? David Brown <david.brown@hesbynett.no> - 2021-07-01 10:29 +0200
      Re: How to write wide char string literals? Juha Nieminen <nospam@thanks.invalid> - 2021-07-01 08:44 +0000
        Re: How to write wide char string literals? David Brown <david.brown@hesbynett.no> - 2021-07-01 12:58 +0200
      Re: How to write wide char string literals? Christian Gollwitzer <auriocus@gmx.de> - 2021-07-01 14:01 +0200
        Re: How to write wide char string literals? David Brown <david.brown@hesbynett.no> - 2021-07-01 14:57 +0200
    Re: How to write wide char string literals? Manfred <noname@add.invalid> - 2021-07-01 15:44 +0200

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