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When using Guix on top of GNU/Linux distribution other than Guix System—a so-called foreign distro—a few additional steps are needed to get everything in place. Here are some of them.
Packages installed via Guix will not use the locale data of the
host system. Instead, you must first install one of the locale packages
available with Guix and then define the GUIX_LOCPATH environment
variable:
$ guix install glibc-locales $ export GUIX_LOCPATH=$HOME/.guix-profile/lib/locale
Note that the glibc-locales package contains data for all the
locales supported by the GNU libc and weighs in at around
917 MiB. Alternatively, the glibc-utf8-locales is smaller but
limited to a few UTF-8 locales.
The GUIX_LOCPATH variable plays a role similar to LOCPATH
(see LOCPATH in The GNU C Library Reference
Manual). There are two important differences though:
GUIX_LOCPATH is honored only by the libc in Guix, and not by the libc
provided by foreign distros. Thus, using GUIX_LOCPATH allows you
to make sure the programs of the foreign distro will not end up loading
incompatible locale data.
GUIX_LOCPATH with /X.Y, where
X.Y is the libc version—e.g., 2.22. This means that,
should your Guix profile contain a mixture of programs linked against
different libc version, each libc version will only try to load locale
data in the right format.
This is important because the locale data format used by different libc versions may be incompatible.
When using Guix on a foreign distro, we strongly recommend that
the system run the GNU C library’s name service cache daemon,
nscd, which should be listening on the
/var/run/nscd/socket socket. Failing to do that, applications
installed with Guix may fail to look up host names or user accounts, or
may even crash. The next paragraphs explain why.
The GNU C library implements a name service switch (NSS), which is an extensible mechanism for “name lookups” in general: host name resolution, user accounts, and more (see Name Service Switch in The GNU C Library Reference Manual).
Being extensible, the NSS supports plugins, which provide new name
lookup implementations: for example, the nss-mdns plugin allow
resolution of .local host names, the nis plugin allows
user account lookup using the Network information service (NIS), and so
on. These extra “lookup services” are configured system-wide in
/etc/nsswitch.conf, and all the programs running on the system
honor those settings (see NSS Configuration File in The GNU C
Reference Manual).
When they perform a name lookup—for instance by calling the
getaddrinfo function in C—applications first try to connect to
the nscd; on success, nscd performs name lookups on their behalf. If
the nscd is not running, then they perform the name lookup by
themselves, by loading the name lookup services into their own address
space and running it. These name lookup services—the
libnss_*.so files—are dlopen’d, but they may come from
the host system’s C library, rather than from the C library the
application is linked against (the C library coming from Guix).
And this is where the problem is: if your application is linked against
Guix’s C library (say, glibc 2.24) and tries to load NSS plugins from
another C library (say, libnss_mdns.so for glibc 2.22), it will
likely crash or have its name lookups fail unexpectedly.
Running nscd on the system, among other advantages, eliminates
this binary incompatibility problem because those libnss_*.so
files are loaded in the nscd process, not in applications
themselves.
The majority of graphical applications use Fontconfig to locate and
load fonts and perform X11-client-side rendering. The fontconfig
package in Guix looks for fonts in $HOME/.guix-profile
by default. Thus, to allow graphical applications installed with Guix
to display fonts, you have to install fonts with Guix as well.
Essential font packages include gs-fonts, font-dejavu, and
font-gnu-freefont.
Once you have installed or removed fonts, or when you notice an application that does not find fonts, you may need to install Fontconfig and to force an update of its font cache by running:
guix install fontconfig fc-cache -rv
To display text written in Chinese languages, Japanese, or Korean in
graphical applications, consider installing
font-adobe-source-han-sans or font-wqy-zenhei. The former
has multiple outputs, one per language family (see Packages with Multiple Outputs). For instance, the following command installs fonts
for Chinese languages:
guix install font-adobe-source-han-sans:cn
Older programs such as xterm do not use Fontconfig and instead
rely on server-side font rendering. Such programs require to specify a
full name of a font using XLFD (X Logical Font Description), like this:
-*-dejavu sans-medium-r-normal-*-*-100-*-*-*-*-*-1
To be able to use such full names for the TrueType fonts installed in your Guix profile, you need to extend the font path of the X server:
xset +fp $(dirname $(readlink -f ~/.guix-profile/share/fonts/truetype/fonts.dir))
After that, you can run xlsfonts (from xlsfonts package)
to make sure your TrueType fonts are listed there.
The nss-certs package provides X.509 certificates, which allow
programs to authenticate Web servers accessed over HTTPS.
When using Guix on a foreign distro, you can install this package and define the relevant environment variables so that packages know where to look for certificates. See X.509 Certificates, for detailed information.
When you install Emacs packages with Guix, the Elisp files are placed
under the share/emacs/site-lisp/ directory of the profile in
which they are installed. The Elisp libraries are made available to
Emacs through the EMACSLOADPATH environment variable, which is
set when installing Emacs itself.
Additionally, autoload definitions are automatically evaluated at the
initialization of Emacs, by the Guix-specific
guix-emacs-autoload-packages procedure. If, for some reason, you
want to avoid auto-loading the Emacs packages installed with Guix, you
can do so by running Emacs with the --no-site-file option
(see Init File in The GNU Emacs Manual).
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