关于libiconv：C使用libiconv将iso ISO？8859-1转换为UTF-8

C convert iso ISO?8859-1 to UTF-8 with libconv

我需要将拉丁ISO？8859-1字符编码为UTF-8(以及相反的操作)。

我首先使用了这个答案是否有办法将UTF8转换为iso-8859-1？执行该操作并起作用；

现在，我想使用提供所有转换机制的libiconv，它应该可以帮助我简化代码。

我遵循了此处提供的示例：
https://www.lemoda.net/c/iconv-example/iconv-example.html

我写了一个看起来像这样的方法：

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char *iconvISO2UTF8(char *iso) {
iconv_t iconvDesc = iconv_open ("ISO?8859-1","UTF-8//TRANSLIT//IGNORE");

if (iconvDesc == (iconv_t) - 1) {
/* Something went wrong. */
if (errno == EINVAL)
fprintf(stderr,"conversion from '%s' to '%s' not available","ISO?8859?1","UTF-8");
else
fprintf(stderr,"LibIcon initialization failure");

return NULL;
}

size_t iconv_value;
char * utf8;
size_t len;
size_t utf8len;
char * utf8start;

int len_start;

len = strlen (iso);
if (! len) {
fprintf(stderr,"iconvISO2UTF8: input String is empty.");
return NULL;
}

/* Assign enough space to put the UTF-8. */
utf8len = 2 * len;
utf8 = calloc (utf8len, sizeof (char));
if (! utf8) {
fprintf(stderr,"iconvISO2UTF8: Calloc failed.");
return NULL;
}
/* Keep track of the variables. */
utf8start = utf8;
len_start = len;

iconv_value = iconv (iconvDesc, & iso, & len, & utf8, & utf8len);
/* Handle failures. */
if (iconv_value == (size_t) - 1) {
switch (errno) {
/* See"man 3 iconv" for an explanation. */
case EILSEQ:
fprintf(stderr,"iconv failed: Invalid multibyte sequence, in string '%s', length %d, out string '%s', length %d\
", iso, (int) len, utf8start, (int) utf8len);
break;
case EINVAL:
fprintf(stderr,"iconv failed: Incomplete multibyte sequence, in string '%s', length %d, out string '%s', length %d\
", iso, (int) len, utf8start, (int) utf8len);
break;
case E2BIG:
fprintf(stderr,"iconv failed: No more room, in string '%s', length %d, out string '%s', length %d\
", iso, (int) len, utf8start, (int) utf8len);
break;
default:
fprintf(stderr,"iconv failed, in string '%s', length %d, out string '%s', length %d\
", iso, (int) len, utf8start, (int) utf8len);
}
return NULL;
}

if(iconv_close (iconvDesc) != 0) {
fprintf(stderr,"libicon close failed: %s", strerror (errno));
}

return utf8start;

}

当我用诸如" abracadabra"之类的普通老式ascii字符来称呼此功能时，iconv可以工作。
但是，一旦我向其中发送突出的字符，例如"éàèü??"然后iconv()调用失败，并显示EILSEQ代码：

iconv failed: Invalid multibyte sequence, in string 'éàèü??', length
6, out string '', length 12

这是一个示例主程序，当存储在以ISO 8859-1编码的源文件中并在以ISO 8859-1作为默认字符集的linux系统上编译时，它会崩溃：

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int main(int argc, char **argv) {
char *iso1 ="abracadabra";
char *utf = iconvISO2UTF8(iso1);
puts(utf);
free(utf);

char *iso2 ="éàèü??";
utf = iconvISO2UTF8(iso2);
puts(utf);
free(utf);
}

是否可以使用iconv运行这种转换？
如果是，此代码有什么问题？