The Microsoft documentation for setlocale() suggests that - since 2018 - they support UTF-8 locales and short (Unix-style) locale identifiers like "en_US". However, I cannot get that to work, not even with Microsoft's own example code. The linked page also contains the up-to-date documentation for setlocale() on Windows.

I'm running a recent Windows 10 system inside VirtualBox. I have tried to switch the locale with (Strawberry) Perl and two versions of MinGW gcc. The result is always the same. I can set the locale to something like "German_Germany.1252" but none of "de_DE", "de-DE", "German_Germany.UTF-8", ".UTF8", "German_Germany.65001", ... work. 65001 is the "code page" for utf-8.

Can anybody shed some light on this?

I'm using this C code for testing (run with "PROGRAMNAME LOCALE"): 

#include <locale.h>
#include <stdio.h>
#include <time.h>
#include <string.h>

int
main(int argc, char *argv[])
{
    char date[256];
    time_t then = 1678658400;
    const char *locale = setlocale(LC_TIME, argv[1]);

    strftime(date, sizeof date, "%B", localtime(&then));
    printf("%s: %s (%u bytes)\n", locale, date, strlen(date));

    return 0;
}

[download]

Or in Perl

use v5.10;
use POSIX qw(LC_ALL setlocale strftime);

my $locale = $ARGV[0];
say "$locale: ", POSIX::setlocale(LC_ALL, $locale);

my $march = strftime("%B", 0, 0, 0, 1, 2, 123);
say $march;

[download]

On non-Windows systems, both versions invoked as "./PROGRAM de_DE.UTF-8" spit out the German word for the month march "März" in utf-8.

In reply to Using setlocale() on Windows with utf-8 support by gflohr

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