将wchar打印到Linux控制台？

Question

我的C程序粘贴在下面.在bash中,程序打印"char is",Ω不打印.我的语言环境都是en_US.utf8.

#include <stdio.h>
#include <wchar.h>
#include <stdlib.h>

int main() {
   int r;
   wchar_t myChar1 = L'?';
   r = wprintf(L"char is %c\n", myChar1);
}

Answer 1

这非常有趣.显然,编译器将omega从UTF-8转换为UNICODE,但不知何故libc将其搞砸了.

首先:%c-format说明符需要a char(甚至在wprintf -version中),因此你必须指定%lc(因此%ls对于字符串).

其次,如果您运行代码,则将语言环境设置为C(它不会自动从环境中获取).您必须setlocale使用空字符串调用以从环境中获取区域设置,因此libc再次开心.

#include <stdio.h>
#include <wchar.h>
#include <stdlib.h>
#include <locale.h>

int main() {
    int r;
    wchar_t myChar1 = L'?';
    setlocale(LC_CTYPE, "");
    r = wprintf(L"char is %lc (%x)\n", myChar1, myChar1);
}

Answer 2

对于建议修复LIBC的答案,您可以这样做:

#include <stdio.h>
#include <wchar.h>
#include <stdlib.h>

// NOTE: *NOT* thread safe, not re-entrant
const char* unicode_to_utf8(wchar_t c)
{
    static unsigned char b_static[5];
    unsigned char* b = b_static; 

    if (c<(1<<7))// 7 bit Unicode encoded as plain ascii
    {
        *b++ = (unsigned char)(c);
    }
    else if (c<(1<<11))// 11 bit Unicode encoded in 2 UTF-8 bytes
    {
        *b++ = (unsigned char)((c>>6)|0xC0);
        *b++ = (unsigned char)((c&0x3F)|0x80);
    }
    else if (c<(1<<16))// 16 bit Unicode encoded in 3 UTF-8 bytes
        {
        *b++ = (unsigned char)(((c>>12))|0xE0);
        *b++ =  (unsigned char)(((c>>6)&0x3F)|0x80);
        *b++ =  (unsigned char)((c&0x3F)|0x80);
    }

    else if (c<(1<<21))// 21 bit Unicode encoded in 4 UTF-8 bytes
    {
        *b++ = (unsigned char)(((c>>18))|0xF0);
        *b++ = (unsigned char)(((c>>12)&0x3F)|0x80);
        *b++ = (unsigned char)(((c>>6)&0x3F)|0x80);
        *b++ = (unsigned char)((c&0x3F)|0x80);
    }
    *b = '\0';
    return b_static;
}


int main() {
    int r;
    wchar_t myChar1 = L'?';
    r = printf("char is %s\n", unicode_to_utf8(myChar1));
    return 0;
}