[Cin] [spam?] Re: Help: clarify some points of the manual

Georgy Salnikov sge at nmr.nioch.nsc.ru
Wed Sep 30 05:26:54 CEST 2020

On Tue, 29 Sep 2020, Phyllis Smith via Cin wrote:

> A program called "xev" that you can type at the prompt on a window which
> brings up a square box but if you move the mouse to that little window and
> type a character, it shows you what the key name is.  For left alt, it is
> Alt_L but right alt has no name.  Another anomaly is the left ctrl key
> which is Ctrl_L and the right ctrl key which is Ctrl_R.

Just now I have checked the same behavior on my computer at work with xev:

Left Ctrl is called Control_L, keycode 37, keysym 0xffe3
Right Ctrl is called Control_R, keycode 105, keysym 0xffe4
Left Alt is called Alt_L, keycode 64, keysym 0xffe9
Right Alt is called Alt_R, keycode 108, keysym 0xffea

So, the right Alt key is active, an application can use it just as it uses
left Alt.

Which key has which name, and whether an X11 application is given chance to
see it at all, depends on the Xorg server configuration: XkbLayout,
XkbVariant, XkbOptions etc.

After that, keystrokes may be catched by the window manager and, may be,
some special key interceptors like, for example, language switchers in
multilingual keyboard configurations, or accessibility tools emulating, for
example, mouse motion via some combination of keys.

For example, I have the following configs:

X.Org X Server 1.9.5
Option "XkbLayout" "us+ru3"
Option "XkbOptions" "terminate:ctrl_alt_bksp,grp:shifts_toggle,grp_led:scroll"
Window manager fvwm-2.6.1 (neither KDE nor GNOME)
Keyboard language switcher xxkb

The xxkb switcher uses a rather exotic key combination Shift_L+Shift_R

The window manager uses several key bindings:

Menu - to set keyboard focus to a selected window
Alt/Shift/Left (Right, Up, Down) to move cursor discretely without mouse

Of course I cannot use the same combinations in any application. Should I
wish to use Alt/Shift/Left in Cinelerra, for example, then I have firstly to
remove the corresponding definitions from my fvwm configfile.

Georgy Salnikov
NMR Group
Novosibirsk Institute of Organic Chemistry
Lavrentjeva, 9, 630090 Novosibirsk, Russia
Phone   +7-383-3307864
Email   sge at nmr.nioch.nsc.ru

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