|
@ -98,3 +98,61 @@ If you want to compile st for OpenBSD you have to remove -lrt from config.mk, an |
|
|
st will compile without any loss of functionality, because all the functions are |
|
|
st will compile without any loss of functionality, because all the functions are |
|
|
included in libc on this platform. |
|
|
included in libc on this platform. |
|
|
|
|
|
|
|
|
|
|
|
## Backspace key does not work |
|
|
|
|
|
|
|
|
|
|
|
This is an issue that was discussed in suckless mailing list |
|
|
|
|
|
<http://lists.suckless.org/dev/1404/20697.html>: |
|
|
|
|
|
|
|
|
|
|
|
Well, I am going to comment why I want to change the behaviour |
|
|
|
|
|
of this key. When ascii was defined in 1968 communication |
|
|
|
|
|
with computers were done using punched cards, or hardcopy |
|
|
|
|
|
terminals (basically a typewritter machine connected with |
|
|
|
|
|
the computer using a serial port). Due to this, ascii defines |
|
|
|
|
|
DELETE as 7F, because in the puched cards, it means all the |
|
|
|
|
|
holes of the card punched, so it is a kind of 'phisical |
|
|
|
|
|
delete'. In the same way, BACKSPACE key was a non destructive |
|
|
|
|
|
back space, as in typewriter machines. So, if you wanted |
|
|
|
|
|
to delete a character, you had to BACKSPACE and then DELETE. |
|
|
|
|
|
Other use of BACKSPACE was accented characters, for example |
|
|
|
|
|
'a BACKSPACE `'. The VT100 had no BACKSPACE key, it was |
|
|
|
|
|
generated using the CONTROL key as another control character |
|
|
|
|
|
(CONTROL key sets to 0 b7 b6 b5, so it converts H (code |
|
|
|
|
|
0x48) into BACKSPACE (code 0x08)), but it had a DELETE key |
|
|
|
|
|
in a similar position where BACKSPACE key is located today |
|
|
|
|
|
in common PC keyboards. All the terminal emulators emulated |
|
|
|
|
|
correctly the difference between these keys, and backspace |
|
|
|
|
|
key generated a BACKSPACE (^H) and delete key generated a |
|
|
|
|
|
DELETE (^?). |
|
|
|
|
|
|
|
|
|
|
|
But the problem arised when Linus Torvald wrote Linux, and |
|
|
|
|
|
he did that the virtual terminal (the terminal emulator |
|
|
|
|
|
integrated in the kernel) returns a DELETE when backspace |
|
|
|
|
|
was pressed, due to the fact of the key in that position |
|
|
|
|
|
in VT100 was a delete key. This created a lot of problems |
|
|
|
|
|
(you can see it in [1] and [2]), and how Linux became the |
|
|
|
|
|
king, a lot of terminal emulators today generate a DELETE |
|
|
|
|
|
when backspace key is pressed in order to avoid problems |
|
|
|
|
|
with linux. It causes that the only way of generating a |
|
|
|
|
|
BACKSPACE in these systems is using CONTROL + H. I also |
|
|
|
|
|
think that emacs had an important point here because CONTROL |
|
|
|
|
|
+ H prefix is used in emacs in some commands (help commands). |
|
|
|
|
|
|
|
|
|
|
|
From point of view of the kernel, you can change the key |
|
|
|
|
|
for deleting a previous character with stty erase. When you |
|
|
|
|
|
connect a real terminal into a machine you describe the |
|
|
|
|
|
type of terminal, so getty configure the correct value of |
|
|
|
|
|
stty erase for this terminal, but in the case of terminal |
|
|
|
|
|
emulators you don't have any getty that can set the correct |
|
|
|
|
|
value of stty erase, so you always get the default value. |
|
|
|
|
|
So it means that in case of changing the value of the |
|
|
|
|
|
backspace keyboard, you have to add a 'stty erase ^H' into |
|
|
|
|
|
your profile. Of course, other solution can be that st |
|
|
|
|
|
itself modify the value of stty erase. I have usually the |
|
|
|
|
|
inverse problem, when I connect with non Unix machines, and |
|
|
|
|
|
I have to press control + h to get a BACKSPACE, or the |
|
|
|
|
|
inverse, when a user connects to my unix machines from a |
|
|
|
|
|
different system with a correct backspace key. |
|
|
|
|
|
|
|
|
|
|
|
[1] http://www.ibb.net/~anne/keyboard.html |
|
|
|
|
|
[2] http://www.tldp.org/HOWTO/Keyboard-and-Console-HOWTO-5.html |
|
|
|
|
|
|