What is the Windows equivalent for en_US.UTF-8 locale?
c++, locale, unicode, utf-8, windows
Solution
In the past UTF-8 (and some other code pages) wasn't allowed as the system locale because
Microsoft said that a UTF-8 locale might break some functions as they were written to assume multibyte encodings used no more than 2 bytes per character, thus code pages with more bytes such as UTF-8 (and also GB 18030, cp54936) could not be set as the locale.
https://en.wikipedia.org/wiki/Unicode_in_Microsoft_Windows#UTF-8
However Microsoft has gradually introduced UTF-8 locale support and started recommending the ANSI APIs (`-A`) again instead of the Unicode (`-W`) versions like before
Until recently, Windows has emphasized "Unicode" `-W` variants over `-A` APIs. However, recent releases have used the ANSI code page and `-A` APIs as a means to introduce UTF-8 support to apps. If the ANSI code page is configured for UTF-8, `-A` APIs operate in UTF-8. This model has the benefit of supporting existing code built with `-A` APIs without any code changes.
-A vs. -W APIs
Firstly they added a "Beta: Use Unicode UTF-8 for worldwide language support" checkbox since Windows 10 insider build 17035 for setting the locale code page to UTF-8
To open that dialog box open start menu, type "region" and select Region settings > Additional date, time & regional settings > Change date, time, or number formats > Administrative
After enabling it you can call `setlocal` as normal:
Starting in Windows 10 build 17134 (April 2018 Update), the Universal C Runtime supports using a UTF-8 code page. This means that `char` strings passed to C runtime functions will expect strings in the UTF-8 encoding. To enable UTF-8 mode, use "UTF-8" as the code page when using `setlocale`. For example, `setlocale(LC_ALL, ".utf8")` will use the current default Windows ANSI code page (ACP) for the locale and UTF-8 for the code page.
UTF-8 Support
You can also use this in older Windows versions
To use this feature on an OS prior to Windows 10, such as Windows 7, you must use app-local deployment or link statically using version 17134 of the Windows SDK or later. For Windows 10 operating systems prior to 17134, only static linking is supported.
Later in 2019 they added the ability for programs to use the UTF-8 locale without even setting the UTF-8 beta flag above. You can use the `/execution-charset:utf-8` or `/utf-8` options when compiling with MSVC or set the ActiveCodePage property in appxmanifest
Problem
If I want to make the following work on Windows, what is the correct locale and how do I detect that it is actually present: Does this code work universaly, or is it just my system?