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Groups > comp.lang.c++ > #67725

Re: How to get standard paths?!?

From Tim Rentsch <tr.17687@z991.linuxsc.com>
Newsgroups comp.lang.c++
Subject Re: How to get standard paths?!?
Date 2019-08-17 22:25 -0700
Organization A noiseless patient Spider
Message-ID <86y2zravv7.fsf@mailhub.linuxsc.com> (permalink)
References (2 earlier) <qj8qil$229$2@news.albasani.net> <qj8ud8$3if$2@dont-email.me> <qj917m$k70$1@news.albasani.net> <86blwnd534.fsf@mailhub.linuxsc.com> <grr2ebFqhjbU1@mid.individual.net>

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Bo Persson <bo@bo-persson.se> writes:

> On 2019-08-17 at 20:22, Tim Rentsch wrote:
>
>> Bonita Montero <Bonita.Montero@gmail.com> writes:
>>
>>>>>> Be advised that in Windows wide strings are UTF-16 encoded.
>>>>>
>>>>> And I think that it would be the best to use std::u16string
>>>>> because wchar_t is not absolutely guaranteed to be 16 bit
>>>>> wide.
>>>>
>>>> It is guaranteed /not/ to be 16-bit on most systems.
>>>
>>> You can be pretty sure that by far most implementations specify
>>> whcar_t as 16 bit since it makes no sense to implement it
>>> differently.  But it's easier to conform to any hypothetical
>>> implementation by using char16_t.
>>
>> (and in another posting quotes the C++ standard)
>>
>>> "Type wchar_t is a distinct type whose values can represent
>>> distinct codes for all members of the largest extended character
>>> set specified among the supported locales (22.3.1)."
>>
>> Like you say, the C and C++ standards require wchar_t to be large
>> enough so one wchar_t object can hold distinct values for every
>> character in the largest supported character set.
>>
>> Most widely used operating systems today (eg, Microsoft Windows,
>> Linux) support character sets with (at least) hundreds of
>> thousands of characters.
>>
>> Can you explain how hundreds of thousands distinct values can be
>> represented in a single 16-bit wide wchar_t object?
>
> No, they would naturally not fit.
>
> But there is a loop-hole here, as the language standard says "the
> supported locales" and not "every existing locale".
>
> So if you only support the locales where 16 bits is enough, you
> haven't broken any rules.  And you cannot help is some people use
> parts of "unsupported" locales as well...

Perhaps not as much of a loophole as you think.  The setlocale()
function is defined, even for C++, by the C standard.  A call to
setlocale() must not accept a locale that has more characters
than wchar_t can accommodate, because of how 'wide character' is
defined.  So the "unsupported" locales you are talking about
cannot be used in a conforming implmentation.  Of course, if the
implementation is not conforming, it can do whatever it wants.

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Thread

How to get standard paths?!? Szyk Cech <szykcech@spoko.pl> - 2019-08-17 13:58 +0200
  Re: How to get standard paths?!? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-08-17 14:02 +0200
    Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 14:05 +0200
      Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 15:11 +0200
        Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 15:59 +0200
          Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 16:20 +0200
            Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 16:28 +0200
              Re: How to get standard paths?!? Ralf Goertz <me@myprovider.invalid> - 2019-08-17 16:37 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 16:54 +0200
                Re: How to get standard paths?!? Paavo Helde <myfirstname@osa.pri.ee> - 2019-08-17 18:37 +0300
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 17:54 +0200
                Re: How to get standard paths?!? Paavo Helde <myfirstname@osa.pri.ee> - 2019-08-17 19:55 +0300
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 19:15 +0200
                Re: How to get standard paths?!? Paavo Helde <myfirstname@osa.pri.ee> - 2019-08-17 20:39 +0300
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 19:44 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 20:10 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 08:58 +0200
                Re: How to get standard paths?!? Bart <bc@freeuk.com> - 2019-08-18 10:16 +0100
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 11:27 +0200
                Re: How to get standard paths?!? Bo Persson <bo@bo-persson.se> - 2019-08-17 21:07 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 21:41 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 17:40 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 17:52 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 18:00 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 18:01 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 18:26 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 20:20 +0200
                Re: How to get standard paths?!? Keith Thompson <kst-u@mib.org> - 2019-08-17 16:33 -0700
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-18 11:34 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 08:48 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-18 11:34 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 12:57 +0200
                Re: How to get standard paths?!? Bart <bc@freeuk.com> - 2019-08-18 13:07 +0100
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 15:49 +0200
                Re: How to get standard paths?!? Bo Persson <bo@bo-persson.se> - 2019-08-18 20:33 +0200
                Re: How to get standard paths?!? Bart <bc@freeuk.com> - 2019-08-18 20:51 +0100
                Re: How to get standard paths?!? Bo Persson <bo@bo-persson.se> - 2019-08-19 00:04 +0200
                Re: How to get standard paths?!? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-25 05:35 -0700
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-25 15:02 +0200
                Re: How to get standard paths?!? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-25 06:38 -0700
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-25 15:46 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-25 15:54 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-19 08:52 +0200
                Re: How to get standard paths?!? "Alf P. Steinbach" <alf.p.steinbach+usenet@gmail.com> - 2019-08-19 09:32 +0200
                Re: How to get standard paths?!? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-22 12:37 -0700
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-19 10:26 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 18:00 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 18:06 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 20:24 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 08:49 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-18 11:46 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 12:59 +0200
                Re: How to get standard paths?!? scott@slp53.sl.home (Scott Lurndal) - 2019-08-18 15:40 +0000
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 17:44 +0200
                Re: How to get standard paths?!? scott@slp53.sl.home (Scott Lurndal) - 2019-08-18 15:38 +0000
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 17:46 +0200
              Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 17:56 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 18:05 +0200
                Re: How to get standard paths?!? Hergen Lehmann <hlehmann.expires.5-11@snafu.de> - 2019-08-17 19:47 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 20:46 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 08:54 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-18 12:07 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 13:05 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-18 14:48 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 15:51 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-18 16:43 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 17:02 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 20:41 +0200
                Re: How to get standard paths?!? Keith Thompson <kst-u@mib.org> - 2019-08-17 16:46 -0700
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-18 12:22 +0200
                Re: How to get standard paths?!? Robert Wessel <robertwessel2@yahoo.com> - 2019-08-17 22:57 -0500
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 08:57 +0200
                Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-18 12:24 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 13:07 +0200
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-18 13:13 +0200
          Re: How to get standard paths?!? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-17 11:22 -0700
            Re: How to get standard paths?!? Bo Persson <bo@bo-persson.se> - 2019-08-17 21:21 +0200
              Re: How to get standard paths?!? Tim Rentsch <tr.17687@z991.linuxsc.com> - 2019-08-17 22:25 -0700
              Re: How to get standard paths?!? Robert Wessel <robertwessel2@yahoo.com> - 2019-08-19 01:19 -0500
                Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-19 08:25 +0200
  Re: How to get standard paths?!? Bonita Montero <Bonita.Montero@gmail.com> - 2019-08-17 14:02 +0200
  Re: How to get standard paths?!? David Brown <david.brown@hesbynett.no> - 2019-08-17 15:13 +0200
  Re: How to get standard paths?!? Sam <sam@email-scan.com> - 2019-08-17 09:21 -0400
  Re: How to get standard paths?!? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-08-19 20:57 +0000

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