Re: Setting keyboard layout on xterm

[Riza Dindir <riza.dindir%gmail.com@localhost>]

Hello Thomas,

When I change the kb layout using "setxkbmap -layout tr" and get the
keyboard layout (with xkbprint...), I can see where the special
characters will be. The locations for these are correct.

But, after changing the keyboard layout to tr, when I press the
"Scedilla" key it does not output anything on xterm (xterm -class
UXTerm, or xterm -u8). But the key labeled "Iabovedot" does output the
"i" character when pressed.

But on X applications, like firefox, I can, after changing the
keyboard layout (to us, or de, or tr), all the keys produce the
characters as expected.

Riza

On Thu, Jun 30, 2022 at 12:11 AM Thomas Dickey <dickey%his.com@localhost> wrote:
>
> On Wed, Jun 29, 2022 at 03:20:21PM -0400, Thomas Dickey wrote:
> > On Wed, Jun 29, 2022 at 05:56:09PM +0200, Martin Husemann wrote:
> > > On Wed, Jun 29, 2022 at 06:21:46PM +0000, Riza Dindir wrote:
> > > > I also changed the font for XTerm in the Xresources file, which uses
> > > > iso8859-9, but that does not do anything. Although the font changes,
> > > > the characters for that language can not be entered on xterm.
> > > >
> > > > Is there a way to do that?
> > >
> > > You need to set the environment variable LC_CTYPE to e.g. de_DE.ISO8859-15
> > > or de_DE.UTF-8 for german (the former giving you ISO 8859-15, the latter
> > > UTF8 unicode encoding), or tr_TR.ISO8859-9 or tr_TR.UTF-8 for turkish.
> > >
> > > You can see all available locales in /usr/share/locale/.
> >
> > just
> >       locale -a
>
> But just "locale" shows what you are actually using.
> On my test-account (not customized) for NetBSD 9.2,
> the locale command shows this in uxterm:
>
>         LANG=""
>         LC_CTYPE="en_US.UTF-8"
>         LC_COLLATE="C"
>         LC_TIME="C"
>         LC_NUMERIC="C"
>         LC_MONETARY="C"
>         LC_MESSAGES="C"
>         LC_ALL=""
>
> and this in xterm:
>
>         LANG=""
>         LC_CTYPE="C"
>         LC_COLLATE="C"
>         LC_TIME="C"
>         LC_NUMERIC="C"
>         LC_MONETARY="C"
>         LC_MESSAGES="C"
>         LC_ALL=""
>
> Since (man locale...) LC_ALL and LANG do nothing when unset, the only
> relevant setting for xterm is LC_CTYPE.  The other settings are used by
> other applications.  For UTF-8 encoding, the country-code tr_TR versus
> en_US.UTF-8 likewise does not matter.  It would be relevant (to other
> applications) if it were not UTF-8.  xterm uses the locale environment
> which is set outside to decide whether to use UTF-8 encoding.  It's
> possible to configure xterm to allow switching after startup, but most
> users don't want or need that.
>
> If xterm were started like this:
>
>         setenv LC_CTYPE en_US.UTF-8
>         xterm
>
> or
>
>         setenv LC_ALL en_US.UTF-8
>         xterm
>
> then the two outputs (from uxterm and xterm) would be the same.  The
> display (using the bitmap font) looks the same with either uxterm or
> xterm started with a locale tweak.  Both, by the way, use a less
> complete font than Debian packages for the same XLFD.  You'll probably
> be better off using TrueType with NetBSD.
>
> While answering this question, I set my locale as described above,
> and the keyboard behaved as expected when using Turkish layout.
> The keys (seen with "cat -v") matched the picture which I obtained
> using these commands:
>
>         setxkbmap -layout tr
>         xkbprint -color "${DISPLAY}" - | ps2pdf - > tr_keyboard_layout.pdf
>
> The "setlocale" manpage is usually the place to go to see how the locale
> environment variables are used.  Looking now, I see that NetBSD does
> this in nls(7):
>
>         The environment variable settings are queried by their priority
>         level in the following manner:
>         ...
>
> The Open Group expands on the environment variables here:
>
> https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_02
>
> LANG
>         This variable shall determine the locale category for native
>         language, local customs, and coded character set in the absence
>         of the LC_ALL and other LC_* (LC_COLLATE, LC_CTYPE, LC_MESSAGES,
>         LC_MONETARY, LC_NUMERIC, LC_TIME) environment variables.  This
>         can be used by applications to determine the language to use for
>         error messages and instructions, collating sequences, date
>         formats, and so on.
> LC_ALL
>         This variable shall determine the values for all locale
>         categories.  The value of the LC_ALL environment variable has
>         precedence over any of the other environment variables starting
>         with LC_ (LC_COLLATE, LC_CTYPE, LC_MESSAGES, LC_MONETARY,
>         LC_NUMERIC, LC_TIME) and the LANG environment variable.
> LC_CTYPE
>         This variable shall determine the locale category for character
>         handling functions, such as tolower(), toupper(), and isalpha().
>         This environment variable determines the interpretation of
>         sequences of bytes of text data as characters (for example,
>         single as opposed to multi-byte characters), the classification
>         of characters (for example, alpha, digit, graph), and the
>         behavior of character classes.  Additional semantics of this
>         variable, if any, are implementation-defined.
>
> --
> Thomas E. Dickey <dickey%invisible-island.net@localhost>
> https://invisible-island.net
> ftp://ftp.invisible-island.net