11.8. Setting Up Locale Information

The /etc/locale.conf below sets some environment variables necessary for native language support. Setting them properly results in:

Replace [ll] below with the two-letter code for the desired language (e.g., “en”) and [CC] with the two-letter code for the appropriate country (e.g., “GB” or “US”). [charmap] should be replaced with the canonical charmap for your chosen locale. Optional modifiers such as “@euro” may also be present.

The list of all locales supported by Glibc can be obtained by running the following command:

locale -a

Locales can have a number of synonyms, e.g. “ISO-8859-1” is also referred to as “iso8859-1” and “iso88591”. Some applications cannot handle the various synonyms correctly, so it is safest to choose the canonical name for a particular locale. To determine the canonical name, run the following command, where [locale name] is the output given by locale -a for your preferred locale (“en_US.utf8” in our example).

LC_ALL=[locale name] locale charmap

For the “en_US.utf8” locale, the above command will print:

UTF-8

This results in a final locale setting of “en_US.UTF-8”. It is important that the locale found using the heuristic above is tested prior to it being added to /etc/locale.conf:

LC_ALL=[locale name] locale territory
LC_ALL=[locale name] locale language
LC_ALL=[locale name] locale charmap
LC_ALL=[locale name] locale int_curr_symbol
LC_ALL=[locale name] locale int_prefix

The above commands should print the language name, the character encoding used by the locale, the local currency, and the prefix to dial before the telephone number in order to get into the country. If any of the commands above fail with a message similar to the one shown below, this means that your locale was either not installed in Chapter 10 or is not supported by the default installation of Glibc.

locale: Cannot set LC_* to default locale: No such file or directory

If this happens, you should either install the desired locale using the localedef command, or consider choosing a different locale. Further instructions assume that there are no such error messages from Glibc.

Some packages beyond CLFS may also lack support for your chosen locale. One example is the X library (part of the X Window System), which outputs the following error message:

Warning: locale not supported by Xlib, locale set to C

Sometimes it is possible to fix this by removing the charmap part of the locale specification, as long as that does not change the character map that Glibc associates with the locale (this can be checked by running the locale charmap command in both locales). For example, one would have to change "de_DE.ISO-8859-15@euro" to "de_DE@euro" in order to get this locale recognized by Xlib.

Other packages can also function incorrectly (but may not necessarily display any error messages) if the locale name does not meet their expectations. In those cases, investigating how other Linux distributions support your locale might provide some useful information.

Once the proper locale settings have been determined, create the /etc/locale.conf file:

cat > /etc/locale.conf << "EOF"
# Begin /etc/locale.conf

LANG=[ll]_[CC].[charmap][@modifiers]

# End /etc/locale.conf
EOF

Note that you can modify /etc/locale.conf with systemd's localectl utility. To use localectl for the example above, run:

localectl set-locale LANG="[ll]_[CC][charmap][@modifiers]"

You can also specify other language specific environment variables such as LANG, LC_CTYPE, LC_NUMERIC or any other environment variable from locale output. Just separate them with a space. An example where LANG is set as en_US.UTF-8 but LC_CTYPE is set as just en_US is:

localectl set-locale LANG="en_US.UTF-8" LC_CTYPE="en_US"

Setting the keyboard layout, screen font, and locale-related environment variables are the only internationalization steps needed to support locales that use ordinary single-byte encodings and left-to-right writing direction. UTF-8 has been tested on the English, French, German, Italian, and Spanish locales. All other locales are untested. If you discover issues with any other locale please open a ticket in our Trac system.

Some locales need additional programs and support. CLFS will not be supporting these locales in the book. We welcome the support for these other locales via http://cblfs.cross-lfs.org/.