Hi all,

I am troubleshooting a locale related issue of our C++ software when building with musl. With some efforts I narrowed our problem down to the inability of setting a UTF-8 locale in C++ standard library.

The following C code prints UTF-8 characters correctly:

#include <ncurses.h>

#include <langinfo.h>

#include <locale.h>

int main()

{

    setlocale(LC_ALL, "");

    initscr();

    printw("LC_ALL: %s\n", setlocale(LC_ALL, NULL));

    printw("CODESET: %s\n", nl_langinfo(CODESET));

    printw("Hello, world!\n");

    printw("你好，世界!\n");

    refresh();

    getch();

    endwin();

    return 0;

}

Giving the output of

LC_ALL: C.UTF-8;C;C;C;C;C

CODESET: UTF-8

Hello, world!

你好，世界!

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;

}

Giving a corrupted output:

LC_ALL: C

C++ locale: C

CODESET: ASCII

Hello, world!

你好?~L?~V?~U~L!

Seems only ASCII C locale is available in C++. If I run the above C++ code with LANG="C.UTF-8", an exception is thrown and the program is aborted:

terminate called after throwing an instance of 'std::runtime_error'

  what():  locale::facet::_S_create_c_locale name not valid

Aborted

I also tried LANG="UTF-8”, LANG="en_US.UTF-8" but none of those works. Only LANG="C" could make the program run but then only ASCII characters are supported.

My question is that is there a way to make locale in C++ standard library work with musl? Or had I done anything wrong with it?

Regards,

Brett