caa1d8fbea
This has been asked many times on IRC and the mailinglist. Make it easier to find information about this particular Xft issue by adding it to the FAQ.
194 lines
8.1 KiB
Text
194 lines
8.1 KiB
Text
## Why does st not handle utmp entries?
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Use the excellent tool of [utmp](http://git.suckless.org/utmp/) for this task.
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## Some _random program_ complains that st is unknown/not recognised/unsupported/whatever!
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It means that st doesn’t have any terminfo entry on your system. Chances are
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you did not `make install`. If you just want to test it without installing it,
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you can manually run `tic -sx st.info`.
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## Nothing works, and nothing is said about an unknown terminal!
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* Some programs just assume they’re running in xterm i.e. they don’t rely on
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terminfo. What you see is the current state of the “xterm compliance”.
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* Some programs don’t complain about the lacking st description and default to
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another terminal. In that case see the question about terminfo.
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## I get some weird glitches/visual bug on _random program_!
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Try launching it with a different TERM: $ TERM=xterm myapp. toe(1) will give
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you a list of available terminals, but you’ll most likely switch between xterm,
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st or st-256color. The default value for TERM can be changed in config.h
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(TNAME).
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## How do I scroll back up?
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Using a terminal multiplexer.
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* `st -e tmux` using C-b [
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* `st -e screen` using C-a ESC
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## Why doesn't the Del key work in some programs?
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Taken from the terminfo manpage:
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If the terminal has a keypad that transmits codes when the keys
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are pressed, this information can be given. Note that it is not
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possible to handle terminals where the keypad only works in
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local (this applies, for example, to the unshifted HP 2621 keys).
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If the keypad can be set to transmit or not transmit, give these
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codes as smkx and rmkx. Otherwise the keypad is assumed to
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always transmit.
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In the st case smkx=E[?1hE= and rmkx=E[?1lE>, so it is mandatory that
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applications which want to test against keypad keys send these
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sequences.
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But buggy applications (like bash and irssi, for example) don't do this. A fast
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solution for them is to use the following command:
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$ printf '\033[?1h\033=' >/dev/tty
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or
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$ tput smkx
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In the case of bash, readline is used. Readline has a different note in its
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manpage about this issue:
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enable-keypad (Off)
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When set to On, readline will try to enable the
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application keypad when it is called. Some systems
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need this to enable arrow keys.
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Adding this option to your .inputrc will fix the keypad problem for all
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applications using readline.
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If you are using zsh, then read the zsh FAQ
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<http://zsh.sourceforge.net/FAQ/zshfaq03.html#l25>:
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It should be noted that the O / [ confusion can occur with other keys
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such as Home and End. Some systems let you query the key sequences
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sent by these keys from the system's terminal database, terminfo.
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Unfortunately, the key sequences given there typically apply to the
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mode that is not the one zsh uses by default (it's the "application"
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mode rather than the "raw" mode). Explaining the use of terminfo is
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outside of the scope of this FAQ, but if you wish to use the key
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sequences given there you can tell the line editor to turn on
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"application" mode when it starts and turn it off when it stops:
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function zle-line-init () { echoti smkx }
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function zle-line-finish () { echoti rmkx }
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zle -N zle-line-init
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zle -N zle-line-finish
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Putting these lines into your .zshrc will fix the problems.
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## How can I use meta in 8bit mode?
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St supports meta in 8bit mode, but the default terminfo entry doesn't
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use this capability. If you want it, you have to use the 'st-meta' value
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in TERM.
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## I cannot compile st in OpenBSD
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OpenBSD lacks librt, despite it being mandatory in POSIX
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<http://pubs.opengroup.org/onlinepubs/9699919799/utilities/c99.html#tag_20_11_13>.
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If you want to compile st for OpenBSD you have to remove -lrt from config.mk, and
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st will compile without any loss of functionality, because all the functions are
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included in libc on this platform.
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## The Backspace Case
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St is emulating the Linux way of handling backspace being delete and delete being
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backspace.
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This is an issue that was discussed in suckless mailing list
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<http://lists.suckless.org/dev/1404/20697.html>. Here is why some old grumpy
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terminal users wants its backspace to be how he feels it:
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Well, I am going to comment why I want to change the behaviour
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of this key. When ASCII was defined in 1968, communication
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with computers was done using punched cards, or hardcopy
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terminals (basically a typewriter machine connected with the
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computer using a serial port). ASCII defines DELETE as 7F,
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because, in punched-card terms, it means all the holes of the
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card punched; it is thus a kind of 'physical delete'. In the
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same way, the BACKSPACE key was a non-destructive backspace,
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as on a typewriter. So, if you wanted to delete a character,
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you had to BACKSPACE and then DELETE. Another use of BACKSPACE
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was to type accented characters, for example 'a BACKSPACE `'.
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The VT100 had no BACKSPACE key; it was generated using the
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CONTROL key as another control character (CONTROL key sets to
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0 b7 b6 b5, so it converts H (code 0x48) into BACKSPACE (code
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0x08)), but it had a DELETE key in a similar position where
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the BACKSPACE key is located today on common PC keyboards.
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All the terminal emulators emulated the difference between
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these keys correctly: the backspace key generated a BACKSPACE
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(^H) and delete key generated a DELETE (^?).
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But a problem arose when Linus Torvalds wrote Linux. Unlike
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earlier terminals, the Linux virtual terminal (the terminal
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emulator integrated in the kernel) returned a DELETE when
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backspace was pressed, due to the VT100 having a DELETE key in
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the same position. This created a lot of problems (see [1]
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and [2]). Since Linux has become the king, a lot of terminal
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emulators today generate a DELETE when the backspace key is
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pressed in order to avoid problems with Linux. The result is
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that the only way of generating a BACKSPACE on these systems
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is by using CONTROL + H. (I also think that emacs had an
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important point here because the CONTROL + H prefix is used
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in emacs in some commands (help commands).)
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From point of view of the kernel, you can change the key
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for deleting a previous character with stty erase. When you
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connect a real terminal into a machine you describe the type
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of terminal, so getty configures the correct value of stty
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erase for this terminal. In the case of terminal emulators,
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however, you don't have any getty that can set the correct
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value of stty erase, so you always get the default value.
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For this reason, it is necessary to add 'stty erase ^H' to your
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profile if you have changed the value of the backspace key.
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Of course, another solution is for st itself to modify the
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value of stty erase. I usually have the inverse problem:
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when I connect to non-Unix machines, I have to press CONTROL +
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h to get a BACKSPACE. The inverse problem occurs when a user
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connects to my Unix machines from a different system with a
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correct backspace key.
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[1] http://www.ibb.net/~anne/keyboard.html
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[2] http://www.tldp.org/HOWTO/Keyboard-and-Console-HOWTO-5.html
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## But I really want the old grumpy behaviour of my terminal
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Apply [1].
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[1] http://st.suckless.org/patches/delkey
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## BadLength X error in Xft when trying to render emoji
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Xft makes st crash when rendering color emojis with the following error:
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"X Error of failed request: BadLength (poly request too large or internal Xlib length error)"
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Major opcode of failed request: 139 (RENDER)
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Minor opcode of failed request: 20 (RenderAddGlyphs)
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Serial number of failed request: 1595
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Current serial number in output stream: 1818"
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This is a known bug in Xft (not st) which happens on some platforms and
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combination of particular fonts and fontconfig settings.
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See also:
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https://gitlab.freedesktop.org/xorg/lib/libxft/issues/6
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https://bugs.freedesktop.org/show_bug.cgi?id=107534
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https://bugzilla.redhat.com/show_bug.cgi?id=1498269
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The solution is to remove color emoji fonts or disable this in the fontconfig
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XML configuration. As an ugly workaround (which may work only on newer
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fontconfig versions (FC_COLOR)), the following code can be used to mask color
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fonts:
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FcPatternAddBool(fcpattern, FC_COLOR, FcFalse);
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Please don't bother reporting this bug to st, but notify the upstream Xft
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developers about fixing this bug.
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