Bug#775952: xterm: VT100.backarrowKey default value vs man page documentation
Control: retitle -1 xterm: VT100.backarrowKey initial value vs man page documentation
On 2015-01-21 22:38:53 +0100, Vincent Lefevre wrote:
> Whether I run
>
> xterm -xrm "*VT100.backarrowKey: true"
>
> or
>
> xterm -xrm "*VT100.backarrowKey: false"
>
> the backarrow key gives the delete (127) character, while the xterm
> man page says:
>
> backarrowKey (class BackarrowKey)
> Specifies whether the backarrow key transmits a backspace (8)
> or delete (127) character. This corresponds to the DECBKM
> control sequence. A “true” value specifies backspace. The
> default is “True”. Pressing the control key toggles this
> behavior.
>
> This is actually the observed behavior only when backarrowKeyIsErase
> is set to false:
>
> xterm -xrm "*backarrowKeyIsErase: false" -xrm ...
>
> I think that when backarrowKeyIsErase is set to true (the default),
> this is the expected behavior, as described under backarrowKeyIsErase,
> and that the man page description of backarrowKey is incorrect.
>
> So, I suppose that the default value of backarrowKey is "true" if
> backarrowKeyIsErase is false; otherwise it depends...
Actually this is not related to the default value (because the
-xrm "*VT100.backarrowKey: ..." overrides the default value).
What apparently happens is that the backarrowKey initial value
is set from the stty erase character if backarrowKeyIsErase is
true. This is just the initial value; the backarrowKey value
can later be changed via the menu[*], for instance.
[*] Backarrow Key (BS/DEL)
Said otherwise, it seems that the initial value is:
1. obtained from the stty erase character if backarrowKeyIsErase
is true;
2. otherwise obtained by an explicit setting of backarrowKey;
3. otherwise set to "True" (the default value).
--
Vincent Lefèvre <vincent@vinc17.net> - Web: <https://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
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