Printing UTF-8 Text to the Windows Console: Sample Code

In a previous blog post, you saw that to print some UTF-8-encoded text to the Windows console, you first have to convert it to UTF-16.

In fact, calling _setmode to change stdout to _O_U8TEXT, and then trying to print UTF-8-encoded text with cout, resulted in a debug assertion failure in the VC++ runtime library. (Please take a look at the aforementioned blog post for more details.)

That blog post lacked some compilable demo code showing the solution, though. So, here you are:

// Test printing UTF-8-encoded text to the Windows console

#include "UnicodeConv.hpp"  // My Unicode conversion helpers

#include <fcntl.h>
#include <io.h>
#include <stdint.h>
#include <iostream>
#include <string>

int main()
{
    // Change stdout to Unicode UTF-16.
    //
    // Note: _O_U8TEXT doesn't seem to work, e.g.:
    // https://blogs.msmvps.com/gdicanio/2017/08/22/printing-utf-8-text-to-the-windows-console/
    //
    _setmode(_fileno(stdout), _O_U16TEXT);


    // Japanese name for Japan, encoded in UTF-8
    uint8_t utf8[] = {
        0xE6, 0x97, 0xA5, // U+65E5
        0xE6, 0x9C, 0xAC, // U+672C
        0x00
    };
    std::string japan(reinterpret_cast<const char*>(utf8));

    // Print UTF-16-encoded text
    std::wcout << Utf16FromUtf8("Connie") << L"\n\n";
    std::wcout << Utf16FromUtf8(japan)    << L'\n';
}

Note that in the above code I test printing out both a pure ASCII string like “Connie” (which is automatically a valid UTF-8-encoded string), and a couple of Japanese kanjis, encoded in UTF-8.

This is the output:

Unicode UTF-8 text converted to UTF-16 and printed out to the Windows console

All right.

Note also that I set the Windows console font to MS Gothic to be able to correctly render the Japanese kanjis.

The compilable C++ source code, including the implementation of the Utf16FromUtf8 Unicode conversion helper function, can be found here on GitHub.