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@@ -0,0 +1,250 @@ +## Why does st not handle utmp entries? + +Use the excellent tool of [utmp](https://git.suckless.org/utmp/) for this task. + + +## Some _random program_ complains that st is unknown/not recognised/unsupported/whatever! + +It means that st doesn’t have any terminfo entry on your system. Chances are +you did not `make install`. If you just want to test it without installing it, +you can manually run `tic -sx st.info`. + + +## Nothing works, and nothing is said about an unknown terminal! + +* Some programs just assume they’re running in xterm i.e. they don’t rely on + terminfo. What you see is the current state of the “xterm compliance”. +* Some programs don’t complain about the lacking st description and default to + another terminal. In that case see the question about terminfo. + + +## How do I scroll back up? + +* Using a terminal multiplexer. + * `st -e tmux` using C-b [ + * `st -e screen` using C-a ESC +* Using the excellent tool of [scroll](https://git.suckless.org/scroll/). +* Using the scrollback [patch](https://st.suckless.org/patches/scrollback/). + + +## I would like to have utmp and/or scroll functionality by default + +You can add the absolute patch of both programs in your config.h +file. You only have to modify the value of utmp and scroll variables. + + +## Why doesn't the Del key work in some programs? + +Taken from the terminfo manpage: + + If the terminal has a keypad that transmits codes when the keys + are pressed, this information can be given. Note that it is not + possible to handle terminals where the keypad only works in + local (this applies, for example, to the unshifted HP 2621 keys). + If the keypad can be set to transmit or not transmit, give these + codes as smkx and rmkx. Otherwise the keypad is assumed to + always transmit. + +In the st case smkx=E[?1hE= and rmkx=E[?1lE>, so it is mandatory that +applications which want to test against keypad keys send these +sequences. + +But buggy applications (like bash and irssi, for example) don't do this. A fast +solution for them is to use the following command: + + $ printf '\033[?1h\033=' >/dev/tty + +or + $ tput smkx + +In the case of bash, readline is used. Readline has a different note in its +manpage about this issue: + + enable-keypad (Off) + When set to On, readline will try to enable the + application keypad when it is called. Some systems + need this to enable arrow keys. + +Adding this option to your .inputrc will fix the keypad problem for all +applications using readline. + +If you are using zsh, then read the zsh FAQ +<http://zsh.sourceforge.net/FAQ/zshfaq03.html#l25>: + + It should be noted that the O / [ confusion can occur with other keys + such as Home and End. Some systems let you query the key sequences + sent by these keys from the system's terminal database, terminfo. + Unfortunately, the key sequences given there typically apply to the + mode that is not the one zsh uses by default (it's the "application" + mode rather than the "raw" mode). Explaining the use of terminfo is + outside of the scope of this FAQ, but if you wish to use the key + sequences given there you can tell the line editor to turn on + "application" mode when it starts and turn it off when it stops: + + function zle-line-init () { echoti smkx } + function zle-line-finish () { echoti rmkx } + zle -N zle-line-init + zle -N zle-line-finish + +Putting these lines into your .zshrc will fix the problems. + + +## How can I use meta in 8bit mode? + +St supports meta in 8bit mode, but the default terminfo entry doesn't +use this capability. If you want it, you have to use the 'st-meta' value +in TERM. + + +## I cannot compile st in OpenBSD + +OpenBSD lacks librt, despite it being mandatory in POSIX +<http://pubs.opengroup.org/onlinepubs/9699919799/utilities/c99.html#tag_20_11_13>. +If you want to compile st for OpenBSD you have to remove -lrt from config.mk, and +st will compile without any loss of functionality, because all the functions are +included in libc on this platform. + + +## The Backspace Case + +St is emulating the Linux way of handling backspace being delete and delete being +backspace. + +This is an issue that was discussed in suckless mailing list +<https://lists.suckless.org/dev/1404/20697.html>. Here is why some old grumpy +terminal users wants its backspace to be how he feels it: + + 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 was done using punched cards, or hardcopy + terminals (basically a typewriter machine connected with the + computer using a serial port). ASCII defines DELETE as 7F, + because, in punched-card terms, it means all the holes of the + card punched; it is thus a kind of 'physical delete'. In the + same way, the BACKSPACE key was a non-destructive backspace, + as on a typewriter. So, if you wanted to delete a character, + you had to BACKSPACE and then DELETE. Another use of BACKSPACE + was to type 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 + the BACKSPACE key is located today on common PC keyboards. + All the terminal emulators emulated the difference between + these keys correctly: the backspace key generated a BACKSPACE + (^H) and delete key generated a DELETE (^?). + + But a problem arose when Linus Torvalds wrote Linux. Unlike + earlier terminals, the Linux virtual terminal (the terminal + emulator integrated in the kernel) returned a DELETE when + backspace was pressed, due to the VT100 having a DELETE key in + the same position. This created a lot of problems (see [1] + and [2]). Since Linux has become the king, a lot of terminal + emulators today generate a DELETE when the backspace key is + pressed in order to avoid problems with Linux. The result is + that the only way of generating a BACKSPACE on these systems + is by using CONTROL + H. (I also think that emacs had an + important point here because the 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 configures the correct value of stty + erase for this terminal. In the case of terminal emulators, + however, you don't have any getty that can set the correct + value of stty erase, so you always get the default value. + For this reason, it is necessary to add 'stty erase ^H' to your + profile if you have changed the value of the backspace key. + Of course, another solution is for st itself to modify the + value of stty erase. I usually have the inverse problem: + when I connect to non-Unix machines, I have to press CONTROL + + h to get a BACKSPACE. The inverse problem occurs 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 + + +## But I really want the old grumpy behaviour of my terminal + +Apply [1]. + +[1] https://st.suckless.org/patches/delkey + + +## Why do images not work in st using the w3m image hack? + +w3mimg uses a hack that draws an image on top of the terminal emulator Drawable +window. The hack relies on the terminal to use a single buffer to draw its +contents directly. + +st uses double-buffered drawing so the image is quickly replaced and may show a +short flicker effect. + +Below is a patch example to change st double-buffering to a single Drawable +buffer. + +diff --git a/x.c b/x.c +--- a/x.c ++++ b/x.c +@@ -732,10 +732,6 @@ xresize(int col, int row) + win.tw = col * win.cw; + win.th = row * win.ch; + +- XFreePixmap(xw.dpy, xw.buf); +- xw.buf = XCreatePixmap(xw.dpy, xw.win, win.w, win.h, +- DefaultDepth(xw.dpy, xw.scr)); +- XftDrawChange(xw.draw, xw.buf); + xclear(0, 0, win.w, win.h); + + /* resize to new width */ +@@ -1148,8 +1144,7 @@ xinit(int cols, int rows) + gcvalues.graphics_exposures = False; + dc.gc = XCreateGC(xw.dpy, parent, GCGraphicsExposures, + &gcvalues); +- xw.buf = XCreatePixmap(xw.dpy, xw.win, win.w, win.h, +- DefaultDepth(xw.dpy, xw.scr)); ++ xw.buf = xw.win; + XSetForeground(xw.dpy, dc.gc, dc.col[defaultbg].pixel); + XFillRectangle(xw.dpy, xw.buf, dc.gc, 0, 0, win.w, win.h); + +@@ -1632,8 +1627,6 @@ xdrawline(Line line, int x1, int y1, int x2) + void + xfinishdraw(void) + { +- XCopyArea(xw.dpy, xw.buf, xw.win, dc.gc, 0, 0, win.w, +- win.h, 0, 0); + XSetForeground(xw.dpy, dc.gc, + dc.col[IS_SET(MODE_REVERSE)? + defaultfg : defaultbg].pixel); + + +## BadLength X error in Xft when trying to render emoji + +Xft makes st crash when rendering color emojis with the following error: + +"X Error of failed request: BadLength (poly request too large or internal Xlib length error)" + Major opcode of failed request: 139 (RENDER) + Minor opcode of failed request: 20 (RenderAddGlyphs) + Serial number of failed request: 1595 + Current serial number in output stream: 1818" + +This is a known bug in Xft (not st) which happens on some platforms and +combination of particular fonts and fontconfig settings. + +See also: +https://gitlab.freedesktop.org/xorg/lib/libxft/issues/6 +https://bugs.freedesktop.org/show_bug.cgi?id=107534 +https://bugzilla.redhat.com/show_bug.cgi?id=1498269 + +The solution is to remove color emoji fonts or disable this in the fontconfig +XML configuration. As an ugly workaround (which may work only on newer +fontconfig versions (FC_COLOR)), the following code can be used to mask color +fonts: + + FcPatternAddBool(fcpattern, FC_COLOR, FcFalse); + +Please don't bother reporting this bug to st, but notify the upstream Xft +developers about fixing this bug. |