cfunction
src/core/os.c on line 1908, column 1
(os/setlocale &opt locale category)
Set the system locale, which affects how dates and numbers are
formatted. Passing nil to locale will return the current locale.
Category can be one of:
* :all (default)
* :collate
* :ctype
* :monetary
* :numeric
* :time
Returns the new locale if set successfully, otherwise nil. Note
that this will affect other functions such as `os/strftime` and
even `printf`.