mailing list of musl libc
 help / color / mirror / code / Atom feed
From: Samuel Holland <samuel@sholland.org>
To: musl@lists.openwall.com, "Érico Nogueira" <ericonr@disroot.org>,
	"Dong Brett" <brett.browning.dong@gmail.com>
Subject: Re: [musl] Question on C++ locale
Date: Mon, 30 Nov 2020 08:39:18 -0600	[thread overview]
Message-ID: <551d3310-039f-23c4-608e-5e15e625f638@sholland.org> (raw)
In-Reply-To: <C7GN68S9FS2B.19BJN1CBUFA60@mussels>

On 11/30/20 7:44 AM, Érico Nogueira wrote:
> On Mon Nov 30, 2020 at 8:35 AM -03, Szabolcs Nagy wrote:
>> * Dong Brett <brett.browning.dong@gmail.com> [2020-11-30 18:41:33
>> +0800]:
>>> However, the following C++ code does not work (our software uses std::locale in C++ standard library for locale related stuff):
>>> #include <langinfo.h>
>>> #include <locale.h>
>>> #include <locale>
>>> using namespace std;
>>> int main()
>>> {
>>>     std::locale::global(locale(""));
>>>     initscr();
>>>     printw("LC_ALL: %s\n", setlocale(LC_ALL, NULL));
>>>     printw("C++ locale: %s\n", locale().name().c_str());
>>>     printw("CODESET: %s\n", nl_langinfo(CODESET));
>>>     printw("Hello, world!\n");
>>>     printw("你好,世界!\n");
>>>     refresh();
>>>     getch();
>>>     endwin();
>>>     return 0;
>>> }
>>
>> fwiw for me even the first line fails.
>> i don't know how c++ locales are supposed to work.
> 
> From [1], it seems that C++ locales are supposed to affect the global
> locale as well, so they should call setlocale() when appropriate.
> 
> - [1] https://www.cplusplus.com/reference/locale/locale/
> 
> Unfortunately, I assume libstdc++ uses their generic locale support on
> musl...  From gcc-10.2.0/libstdc++-v3/config/locale/generic/c_locale.cc:
> 
>   void
>   locale::facet::_S_create_c_locale(__c_locale& __cloc, const char* __s,
> 				    __c_locale)
>   {
>     // Currently, the generic model only supports the "C" locale.
>     // See http://gcc.gnu.org/ml/libstdc++/2003-02/msg00345.html
>     __cloc = 0;
>     if (strcmp(__s, "C"))
>       __throw_runtime_error(__N("locale::facet::_S_create_c_locale "
> 			    "name not valid"));
>   }
> 

I don't know for sure that it's the right thing to do, but I have been patching
out that error for the last several years[1] and so far I have not noticed any
negative effects. Adelie, which is very thorough about testing, has also carried
the patch for a while[2].

Samuel

[1]:
https://github.com/smaeul/portage/blob/c744774a/patches/sys-devel/gcc/gcc-5.4.0-locale.patch
[2]: https://code.foxkit.us/adelie/packages/-/commit/d09b437d

  reply	other threads:[~2020-11-30 14:39 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-30 10:41 Dong Brett
2020-11-30 11:31 ` Szabolcs Nagy
2020-11-30 11:58   ` Dong Brett
2020-11-30 11:35 ` Szabolcs Nagy
2020-11-30 12:37   ` Érico Nogueira
2020-11-30 13:44   ` Érico Nogueira
2020-11-30 14:39     ` Samuel Holland [this message]
2020-11-30 14:48       ` Rich Felker
2020-11-30 15:12       ` Érico Nogueira
2020-11-30 15:35         ` Rich Felker
2020-11-30 17:14           ` Érico Nogueira
2020-11-30 18:11             ` Rich Felker
2020-11-30 14:51 ` Rich Felker
2020-12-09 14:35   ` Érico Nogueira
2020-12-09 16:41     ` Rich Felker
2020-12-01  3:53 ` [musl] " Dong Brett
2020-12-01 16:21   ` Rich Felker

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=551d3310-039f-23c4-608e-5e15e625f638@sholland.org \
    --to=samuel@sholland.org \
    --cc=brett.browning.dong@gmail.com \
    --cc=ericonr@disroot.org \
    --cc=musl@lists.openwall.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://git.vuxu.org/mirror/musl/

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).