看看 ICU用户指南.对于简单的(单字符)案例映射，可以使用 u_toupper 代码> .对于完整案例映射，请使用 u_strToUpper .示例代码:

Have a look at the ICU User Guide. For simple (single-character) case mapping, you can use u_toupper. For full case mapping, use u_strToUpper. Example code:

#include <unicode/uchar.h>
#include <unicode/ustdio.h>
#include <unicode/ustring.h>

int main() {
    UChar32 upper = u_toupper(U'ij');
    u_printf("%lC\n", upper);

    UChar src = u'ß';
    UChar dest[3];
    UErrorCode err = U_ZERO_ERROR;
    u_strToUpper(dest, 3, &src, 1, NULL, &err);
    u_printf("%S\n", dest);

    return 0;
}