The following code works as expected. The source code, file "file.txt" and "out.txt" are all encoded with utf8. But it does not work when I change wchar_t to char16_t at the first line in main(). I've tried both gcc5.4 and clang8.0 with -std=c++11. My goal is to replace wchar_t with char16_t, as wchar_t takes twice space in RAM. I thought these 2 types are equally well supported in c++11 and later standards. What do I miss here?
#include<iostream>
#include<fstream>
#include<locale>
#include<codecvt>
#include<string>
int main(){
typedef wchar_t my_char;
std::locale::global(std::locale("en_US.UTF-8"));
std::ofstream out("file.txt");
out << "123正则表达式abc" << std::endl;
out.close();
std::basic_ifstream<my_char> win("file.txt");
std::basic_string<my_char> wstr;
win >> wstr;
win.close();
std::ifstream in("file.txt");
std::string str;
in >> str;
in.close();
std::wstring_convert<std::codecvt_utf8<my_char>, my_char> my_char_conv;
std::basic_string<my_char> conv = my_char_conv.from_bytes(str);
std::cout << (wstr == conv ? "true" : "false") << std::endl;
std::basic_ofstream<my_char> wout("out.txt");
wout << wstr << std::endl << conv << std::endl;
wout.close();
return 0;
}
EDIT
The modified code does not compile with clang8.0. It compiles with gcc5.4 but crashes at run-time as shown by @Brian.