PHP setlocale depends on underlying system (XAMPP on Windows)

I’m maintaining a few websites, so I have a local webserver running to do testing and debugging. Until recently, I was using IIS on my Windows laptop. However, I ditched IIS a while ago, replacing it with XAMPP. This is much closer to the environment that’s running the websites (e.g. I can use .htaccess directly, rather than converting it to a web.config file).

This all worked fine, except for setlocale in PHP. I wanted to use Dutch (Belgian), but I could not get
setlocale(LC_ALL, 'nl_BE');
to work on my local machine.

I searched the web, but did not find any useful information. So I looked at the PHP setlocale helpinfo again, and noticed the Tip in the NotesWindows users will find useful information about locale strings at Microsoft’s MSDN website.

After checking, it turned out that Microsoft decided to go for another “standard”, so ‘nl_BE’ was not recognized. To use Dutch on Windows, I needed
setlocale(LC_ALL, 'nld_nld');

Oh well…