Locale oddity

[Polytropon]

On Sun, 19 Jul 2020 19:14:44 +0200, Morten Bo Johansen via freebsd-questions wrote:
> If I unset the $LANG variable, then all other LC_* category
> locale variables will automatically be set to "C" except for
> the $LC_ALL variable:
> 
>   ~/ % LANG= locale
>   LANG=
>   LC_CTYPE="C"
>   LC_COLLATE="C"
>   LC_TIME="C"
>   LC_NUMERIC="C"
>   LC_MONETARY="C"
>   LC_MESSAGES="C"
>   LC_ALL=
> 
> Otherwise they are:
> 
>   ~/ % locale    
>   LANG=da_DK.UTF-8
>   LC_CTYPE="da_DK.UTF-8"
>   LC_COLLATE="da_DK.UTF-8"
>   LC_TIME="da_DK.UTF-8"
>   LC_NUMERIC="da_DK.UTF-8"
>   LC_MONETARY="da_DK.UTF-8"
>   LC_MESSAGES="da_DK.UTF-8"
>   LC_ALL=
> 
> I don't understand this behaviour. Could someone explain the
> logic of this to me?

There is a certain "precedence" in the language variables:
IF $LANG is set, all others are ignored; if $LC_ALL is set,
all other $LC_*s will be ignored.

You can find more information in "man 3 setlocale":

	Only three locales are defined by default, the empty
	string "" which denotes the native environment, and
	the "C" and "POSIX" locales, which denote the C
	language environment. [...] By default, C programs
	start in the "C" locale.

The Handbook also has detailed information in section 22.2.

https://www.freebsd.org/doc/handbook/using-localization.html

So what you see is correct and expected: All $LC_* variables
except $LC_ALL will default to "C", otherwise they will
inherit what $LANG contains; $LC_ALL will not be set
automatically to anything.


-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...