如何将#defined string literal转换为宽字符串文字？

#define WIDE_STRING_LITERAL L"Hello, world!"

#include<string>

#define STRING_LITERAL "Hello, world!"
#define WIDE_STRING_LITERAL std::wstring(L"Hello, world!")

int main() {
    std::wstring wide_string = WIDE_STRING_LITERAL;
    return 0;
}

#include<Windows.h>
#include<iostream>

#define STRING_LITERAL "Hello, world!"

int main() {
    int len = MultiByteToWideChar(CP_UTF8, 0, STRING_LITERAL, -1, NULL, 0);
    if (len == 0) {
        std::cerr << "MultiByteToWideChar failed"<< std::endl;
        return 1;
    }

    std::wstring wide_string(len, 0);
    MultiByteToWideChar(CP_UTF8, 0, STRING_LITERAL, -1, &wide_string[0], len);

    return 0;
}