Read Unicode UTF-8 file into wstring

Question

How can I read a Unicode (UTF-8) file into wstring(s) on the Windows platform?

Answer 1

According to a comment by @Hans Passant, the simplest way is to use _wfopen_s. Open the file with mode rt, ccs=UTF-8.

Here is another pure C++ solution that works at least with VC++ 2010:

#include 
#include 
#include 
#include 
#include 

int main() {
    const std::locale empty_locale = std::locale::empty();
    typedef std::codecvt_utf8 converter_type;
    const converter_type* converter = new converter_type;
    const std::locale utf8_locale = std::locale(empty_locale, converter);
    std::wifstream stream(L"test.txt");
    stream.imbue(utf8_locale);
    std::wstring line;
    std::getline(stream, line);
    std::system("pause");
}

Except for locale::empty() (here locale::global() might work as well) and the wchar_t* overload of the basic_ifstream constructor, this should even be pretty standard-compliant (where “standard” means C++0x, of course).