On 03.04.2019 7:47, Eli Zaretskii wrote:
> On Tue, 2 Apr 2019 23:57:35 +0300 Владимир Мартьянов wrote:
>>
>> I'm able to use results from setlocale(), but how can the user
>> influenсe the result of setlocale?
> 
> Beware: only the Cygwin setlocale supports environment variables, the
> native MS-Windows implementation used by MinGW does not.
> 

That's what gettext is for. And/or gnulib.