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Revision: 1.59
Committed: Sat Jul 24 14:20:48 2010 UTC (13 years, 9 months ago) by sf-exg
Branch: MAIN
Changes since 1.58: +9 -13 lines
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# User Rev Content
1 root 1.42 RXVT-UNICODE/URXVT FREQUENTLY ASKED QUESTIONS
2     Meta, Features & Commandline Issues
3     My question isn't answered here, can I ask a human?
4     Before sending me mail, you could go to IRC: "irc.freenode.net", channel
5     "#rxvt-unicode" has some rxvt-unicode enthusiasts that might be
6     interested in learning about new and exciting problems (but not FAQs :).
7    
8 root 1.56 I use Gentoo, and I have a problem...
9     There are three big problems with Gentoo Linux: first of all, most if
10     not all Gentoo systems are completely broken (missing or mismatched
11     header files, broken compiler etc. are just the tip of the iceberg);
12     secondly, the Gentoo maintainer thinks it is a good idea to add broken
13     patches to the code; and lastly, it should be called Gentoo GNU/Linux.
14    
15     For these reasons, it is impossible to support rxvt-unicode on Gentoo.
16     Problems appearing on Gentoo systems will usually simply be ignored
17     unless they can be reproduced on non-Gentoo systems.
18    
19 root 1.42 Does it support tabs, can I have a tabbed rxvt-unicode?
20     Beginning with version 7.3, there is a perl extension that implements a
21     simple tabbed terminal. It is installed by default, so any of these
22     should give you tabs:
23    
24     urxvt -pe tabbed
25    
26     URxvt.perl-ext-common: default,tabbed
27    
28     It will also work fine with tabbing functionality of many window
29     managers or similar tabbing programs, and its embedding-features allow
30     it to be embedded into other programs, as witnessed by doc/rxvt-tabbed
31     or the upcoming "Gtk2::URxvt" perl module, which features a tabbed urxvt
32     (murxvt) terminal as an example embedding application.
33    
34     How do I know which rxvt-unicode version I'm using?
35     The version number is displayed with the usage (-h). Also the escape
36     sequence "ESC [ 8 n" sets the window title to the version number. When
37     using the urxvtc client, the version displayed is that of the daemon.
38    
39     Rxvt-unicode uses gobs of memory, how can I reduce that?
40     Rxvt-unicode tries to obey the rule of not charging you for something
41     you don't use. One thing you should try is to configure out all settings
42     that you don't need, for example, Xft support is a resource hog by
43     design, when used. Compiling it out ensures that no Xft font will be
44     loaded accidentally when rxvt-unicode tries to find a font for your
45     characters.
46    
47     Also, many people (me included) like large windows and even larger
48     scrollback buffers: Without "--enable-unicode3", rxvt-unicode will use 6
49     bytes per screen cell. For a 160x?? window this amounts to almost a
50     kilobyte per line. A scrollback buffer of 10000 lines will then (if
51     full) use 10 Megabytes of memory. With "--enable-unicode3" it gets
52     worse, as rxvt-unicode then uses 8 bytes per screen cell.
53    
54     How can I start urxvtd in a race-free way?
55     Try "urxvtd -f -o", which tells urxvtd to open the display, create the
56     listening socket and then fork.
57    
58 root 1.45 How can I start urxvtd automatically when I run urxvtc?
59 root 1.42 If you want to start urxvtd automatically whenever you run urxvtc and
60     the daemon isn't running yet, use this script:
61    
62     #!/bin/sh
63     urxvtc "$@"
64     if [ $? -eq 2 ]; then
65     urxvtd -q -o -f
66     urxvtc "$@"
67     fi
68    
69     This tries to create a new terminal, and if fails with exit status 2,
70     meaning it couldn't connect to the daemon, it will start the daemon and
71     re-run the command. Subsequent invocations of the script will re-use the
72     existing daemon.
73    
74 sf-exg 1.59 How do I distinguish whether I'm running rxvt-unicode or a regular
75     xterm? I need this to decide about setting colours etc.
76 root 1.42 The original rxvt and rxvt-unicode always export the variable
77     "COLORTERM", so you can check and see if that is set. Note that several
78     programs, JED, slrn, Midnight Commander automatically check this
79 sf-exg 1.59 variable to decide whether or not to use colour.
80 root 1.42
81     How do I set the correct, full IP address for the DISPLAY variable?
82     If you've compiled rxvt-unicode with DISPLAY_IS_IP and have enabled
83     insecure mode then it is possible to use the following shell script
84     snippets to correctly set the display. If your version of rxvt-unicode
85     wasn't also compiled with ESCZ_ANSWER (as assumed in these snippets)
86     then the COLORTERM variable can be used to distinguish rxvt-unicode from
87     a regular xterm.
88    
89     Courtesy of Chuck Blake <cblake@BBN.COM> with the following shell script
90     snippets:
91    
92     # Bourne/Korn/POSIX family of shells:
93     [ ${TERM:-foo} = foo ] && TERM=xterm # assume an xterm if we don't know
94     if [ ${TERM:-foo} = xterm ]; then
95     stty -icanon -echo min 0 time 15 # see if enhanced rxvt or not
96     echo -n '^[Z'
97     read term_id
98     stty icanon echo
99     if [ ""${term_id} = '^[[?1;2C' -a ${DISPLAY:-foo} = foo ]; then
100     echo -n '^[[7n' # query the rxvt we are in for the DISPLAY string
101     read DISPLAY # set it in our local shell
102     fi
103     fi
104    
105     How do I compile the manual pages on my own?
106     You need to have a recent version of perl installed as /usr/bin/perl,
107 root 1.49 one that comes with pod2man, pod2text and pod2xhtml (from Pod::Xhtml).
108 root 1.48 Then go to the doc subdirectory and enter "make alldoc".
109 root 1.42
110     Isn't rxvt-unicode supposed to be small? Don't all those features bloat?
111     I often get asked about this, and I think, no, they didn't cause extra
112     bloat. If you compare a minimal rxvt and a minimal urxvt, you can see
113     that the urxvt binary is larger (due to some encoding tables always
114     being compiled in), but it actually uses less memory (RSS) after
115     startup. Even with "--disable-everything", this comparison is a bit
116     unfair, as many features unique to urxvt (locale, encoding conversion,
117     iso14755 etc.) are already in use in this mode.
118    
119     text data bss drs rss filename
120     98398 1664 24 15695 1824 rxvt --disable-everything
121     188985 9048 66616 18222 1788 urxvt --disable-everything
122    
123     When you "--enable-everything" (which *is* unfair, as this involves xft
124     and full locale/XIM support which are quite bloaty inside libX11 and my
125 root 1.43 libc), the two diverge, but not unreasonably so.
126 root 1.42
127     text data bss drs rss filename
128     163431 2152 24 20123 2060 rxvt --enable-everything
129     1035683 49680 66648 29096 3680 urxvt --enable-everything
130    
131     The very large size of the text section is explained by the east-asian
132     encoding tables, which, if unused, take up disk space but nothing else
133     and can be compiled out unless you rely on X11 core fonts that use those
134     encodings. The BSS size comes from the 64k emergency buffer that my c++
135     compiler allocates (but of course doesn't use unless you are out of
136     memory). Also, using an xft font instead of a core font immediately adds
137     a few megabytes of RSS. Xft indeed is responsible for a lot of RSS even
138     when not used.
139    
140     Of course, due to every character using two or four bytes instead of
141     one, a large scrollback buffer will ultimately make rxvt-unicode use
142     more memory.
143    
144     Compared to e.g. Eterm (5112k), aterm (3132k) and xterm (4680k), this
145     still fares rather well. And compared to some monsters like
146     gnome-terminal (21152k + extra 4204k in separate processes) or konsole
147     (22200k + extra 43180k in daemons that stay around after exit, plus half
148     a minute of startup time, including the hundreds of warnings it spits
149     out), it fares extremely well *g*.
150    
151     Why C++, isn't that unportable/bloated/uncool?
152     Is this a question? :) It comes up very often. The simple answer is: I
153     had to write it, and C++ allowed me to write and maintain it in a
154     fraction of the time and effort (which is a scarce resource for me). Put
155     even shorter: It simply wouldn't exist without C++.
156    
157     My personal stance on this is that C++ is less portable than C, but in
158     the case of rxvt-unicode this hardly matters, as its portability limits
159     are defined by things like X11, pseudo terminals, locale support and
160     unix domain sockets, which are all less portable than C++ itself.
161    
162     Regarding the bloat, see the above question: It's easy to write programs
163     in C that use gobs of memory, an certainly possible to write programs in
164     C++ that don't. C++ also often comes with large libraries, but this is
165     not necessarily the case with GCC. Here is what rxvt links against on my
166     system with a minimal config:
167    
168     libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x00002aaaaabc3000)
169     libc.so.6 => /lib/libc.so.6 (0x00002aaaaadde000)
170     libdl.so.2 => /lib/libdl.so.2 (0x00002aaaab01d000)
171     /lib64/ld-linux-x86-64.so.2 (0x00002aaaaaaab000)
172    
173     And here is rxvt-unicode:
174    
175     libX11.so.6 => /usr/X11R6/lib/libX11.so.6 (0x00002aaaaabc3000)
176     libgcc_s.so.1 => /lib/libgcc_s.so.1 (0x00002aaaaada2000)
177 root 1.51 libc.so.6 => /lib/libc.so.6 (0x00002aaaaaeb0000)
178     libdl.so.2 => /lib/libdl.so.2 (0x00002aaaab0ee000)
179     /lib64/ld-linux-x86-64.so.2 (0x00002aaaaaaab000)
180 root 1.42
181     No large bloated libraries (of course, none were linked in statically),
182     except maybe libX11 :)
183    
184     Rendering, Font & Look and Feel Issues
185     I can't get transparency working, what am I doing wrong?
186 root 1.50 First of all, please address all transparency related issues to Sasha
187     Vasko at sasha@aftercode.net and do not bug the author about it. Also,
188     if you can't get it working consider it a rite of passage: ... and you
189     failed.
190 root 1.42
191     Here are four ways to get transparency. Do read the manpage and option
192     descriptions for the programs mentioned and rxvt-unicode. Really, do it!
193    
194 root 1.51 1. Use transparent mode:
195 root 1.42
196     Esetroot wallpaper.jpg
197 root 1.51 urxvt -tr -tint red -sh 40
198 root 1.42
199     That works. If you think it doesn't, you lack transparency and tinting
200     support, or you are unable to read.
201    
202     2. Use a simple pixmap and emulate pseudo-transparency. This enables you
203     to use effects other than tinting and shading: Just shade/tint/whatever
204     your picture with gimp or any other tool:
205    
206 root 1.50 convert wallpaper.jpg -blur 20x20 -modulate 30 background.jpg
207 root 1.51 urxvt -pixmap "background.jpg;:root"
208 root 1.42
209 root 1.51 That works. If you think it doesn't, you lack AfterImage support, or you
210     are unable to read.
211 root 1.42
212     3. Use an ARGB visual:
213    
214     urxvt -depth 32 -fg grey90 -bg rgba:0000/0000/4444/cccc
215    
216     This requires XFT support, and the support of your X-server. If that
217     doesn't work for you, blame Xorg and Keith Packard. ARGB visuals aren't
218     there yet, no matter what they claim. Rxvt-Unicode contains the
219 root 1.43 necessary bugfixes and workarounds for Xft and Xlib to make it work, but
220     that doesn't mean that your WM has the required kludges in place.
221 root 1.42
222     4. Use xcompmgr and let it do the job:
223    
224     xprop -frame -f _NET_WM_WINDOW_OPACITY 32c \
225     -set _NET_WM_WINDOW_OPACITY 0xc0000000
226    
227     Then click on a window you want to make transparent. Replace 0xc0000000
228     by other values to change the degree of opacity. If it doesn't work and
229     your server crashes, you got to keep the pieces.
230    
231     Why does rxvt-unicode sometimes leave pixel droppings?
232     Most fonts were not designed for terminal use, which means that
233     character size varies a lot. A font that is otherwise fine for terminal
234     use might contain some characters that are simply too wide. Rxvt-unicode
235     will avoid these characters. For characters that are just "a bit" too
236     wide a special "careful" rendering mode is used that redraws adjacent
237     characters.
238    
239     All of this requires that fonts do not lie about character sizes,
240     however: Xft fonts often draw glyphs larger than their acclaimed
241     bounding box, and rxvt-unicode has no way of detecting this (the correct
242     way is to ask for the character bounding box, which unfortunately is
243     wrong in these cases).
244    
245 root 1.43 It's not clear (to me at least), whether this is a bug in Xft, freetype,
246 root 1.42 or the respective font. If you encounter this problem you might try
247     using the "-lsp" option to give the font more height. If that doesn't
248     work, you might be forced to use a different font.
249    
250     All of this is not a problem when using X11 core fonts, as their
251     bounding box data is correct.
252    
253     How can I keep rxvt-unicode from using reverse video so much?
254     First of all, make sure you are running with the right terminal settings
255     ("TERM=rxvt-unicode"), which will get rid of most of these effects. Then
256     make sure you have specified colours for italic and bold, as otherwise
257     rxvt-unicode might use reverse video to simulate the effect:
258    
259     URxvt.colorBD: white
260     URxvt.colorIT: green
261    
262     Some programs assume totally weird colours (red instead of blue), how can I fix that?
263     For some unexplainable reason, some rare programs assume a very weird
264     colour palette when confronted with a terminal with more than the
265     standard 8 colours (rxvt-unicode supports 88). The right fix is, of
266     course, to fix these programs not to assume non-ISO colours without very
267     good reasons.
268    
269     In the meantime, you can either edit your "rxvt-unicode" terminfo
270     definition to only claim 8 colour support or use "TERM=rxvt", which will
271     fix colours but keep you from using other rxvt-unicode features.
272    
273     Can I switch the fonts at runtime?
274     Yes, using an escape sequence. Try something like this, which has the
275     same effect as using the "-fn" switch, and takes effect immediately:
276    
277     printf '\33]50;%s\007' "9x15bold,xft:Kochi Gothic"
278    
279     This is useful if you e.g. work primarily with japanese (and prefer a
280     japanese font), but you have to switch to chinese temporarily, where
281     japanese fonts would only be in your way.
282    
283     You can think of this as a kind of manual ISO-2022 switching.
284    
285     Why do italic characters look as if clipped?
286     Many fonts have difficulties with italic characters and hinting. For
287     example, the otherwise very nicely hinted font "xft:Bitstream Vera Sans
288     Mono" completely fails in its italic face. A workaround might be to
289     enable freetype autohinting, i.e. like this:
290    
291     URxvt.italicFont: xft:Bitstream Vera Sans Mono:italic:autohint=true
292     URxvt.boldItalicFont: xft:Bitstream Vera Sans Mono:bold:italic:autohint=true
293    
294     Can I speed up Xft rendering somehow?
295     Yes, the most obvious way to speed it up is to avoid Xft entirely, as it
296     is simply slow. If you still want Xft fonts you might try to disable
297     antialiasing (by appending ":antialias=false"), which saves lots of
298     memory and also speeds up rendering considerably.
299    
300     Rxvt-unicode doesn't seem to anti-alias its fonts, what is wrong?
301     Rxvt-unicode will use whatever you specify as a font. If it needs to
302     fall back to its default font search list it will prefer X11 core fonts,
303     because they are small and fast, and then use Xft fonts. It has
304     antialiasing disabled for most of them, because the author thinks they
305     look best that way.
306    
307     If you want antialiasing, you have to specify the fonts manually.
308    
309     What's with this bold/blink stuff?
310     If no bold colour is set via "colorBD:", bold will invert text using the
311     standard foreground colour.
312    
313     For the standard background colour, blinking will actually make the text
314 root 1.52 blink when compiled with "--enable-text-blink". Without
315     "--enable-text-blink", the blink attribute will be ignored.
316 root 1.42
317     On ANSI colours, bold/blink attributes are used to set high-intensity
318 sf-exg 1.59 foreground/background colours.
319 root 1.42
320 sf-exg 1.59 color0-7 are the low-intensity colours.
321 root 1.42
322 sf-exg 1.59 color8-15 are the corresponding high-intensity colours.
323 root 1.42
324 sf-exg 1.59 I don't like the screen colours. How do I change them?
325     You can change the screen colours at run-time using ~/.Xdefaults
326 root 1.42 resources (or as long-options).
327    
328     Here are values that are supposed to resemble a VGA screen, including
329     the murky brown that passes for low-intensity yellow:
330    
331     URxvt.color0: #000000
332     URxvt.color1: #A80000
333     URxvt.color2: #00A800
334     URxvt.color3: #A8A800
335     URxvt.color4: #0000A8
336     URxvt.color5: #A800A8
337     URxvt.color6: #00A8A8
338     URxvt.color7: #A8A8A8
339    
340     URxvt.color8: #000054
341     URxvt.color9: #FF0054
342     URxvt.color10: #00FF54
343     URxvt.color11: #FFFF54
344     URxvt.color12: #0000FF
345     URxvt.color13: #FF00FF
346     URxvt.color14: #00FFFF
347     URxvt.color15: #FFFFFF
348    
349 sf-exg 1.59 And here is a more complete set of non-standard colours.
350 root 1.42
351     URxvt.cursorColor: #dc74d1
352     URxvt.pointerColor: #dc74d1
353     URxvt.background: #0e0e0e
354     URxvt.foreground: #4ad5e1
355     URxvt.color0: #000000
356     URxvt.color8: #8b8f93
357     URxvt.color1: #dc74d1
358     URxvt.color9: #dc74d1
359     URxvt.color2: #0eb8c7
360     URxvt.color10: #0eb8c7
361     URxvt.color3: #dfe37e
362     URxvt.color11: #dfe37e
363     URxvt.color5: #9e88f0
364     URxvt.color13: #9e88f0
365     URxvt.color6: #73f7ff
366     URxvt.color14: #73f7ff
367     URxvt.color7: #e1dddd
368     URxvt.color15: #e1dddd
369    
370     They have been described (not by me) as "pretty girly".
371    
372     Why do some characters look so much different than others?
373     See next entry.
374    
375     How does rxvt-unicode choose fonts?
376     Most fonts do not contain the full range of Unicode, which is fine.
377     Chances are that the font you (or the admin/package maintainer of your
378     system/os) have specified does not cover all the characters you want to
379     display.
380    
381     rxvt-unicode makes a best-effort try at finding a replacement font.
382     Often the result is fine, but sometimes the chosen font looks
383     bad/ugly/wrong. Some fonts have totally strange characters that don't
384     resemble the correct glyph at all, and rxvt-unicode lacks the artificial
385     intelligence to detect that a specific glyph is wrong: it has to believe
386     the font that the characters it claims to contain indeed look correct.
387    
388     In that case, select a font of your taste and add it to the font list,
389     e.g.:
390    
391     urxvt -fn basefont,font2,font3...
392    
393     When rxvt-unicode sees a character, it will first look at the base font.
394     If the base font does not contain the character, it will go to the next
395     font, and so on. Specifying your own fonts will also speed up this
396     search and use less resources within rxvt-unicode and the X-server.
397    
398     The only limitation is that none of the fonts may be larger than the
399     base font, as the base font defines the terminal character cell size,
400     which must be the same due to the way terminals work.
401    
402     Why do some chinese characters look so different than others?
403     This is because there is a difference between script and language --
404     rxvt-unicode does not know which language the text that is output is, as
405     it only knows the unicode character codes. If rxvt-unicode first sees a
406     japanese/chinese character, it might choose a japanese font for display.
407     Subsequent japanese characters will use that font. Now, many chinese
408     characters aren't represented in japanese fonts, so when the first
409     non-japanese character comes up, rxvt-unicode will look for a chinese
410     font -- unfortunately at this point, it will still use the japanese font
411     for chinese characters that are also in the japanese font.
412    
413     The workaround is easy: just tag a chinese font at the end of your font
414     list (see the previous question). The key is to view the font list as a
415     preference list: If you expect more japanese, list a japanese font
416     first. If you expect more chinese, put a chinese font first.
417    
418     In the future it might be possible to switch language preferences at
419     runtime (the internal data structure has no problem with using different
420     fonts for the same character at the same time, but no interface for this
421     has been designed yet).
422    
423     Until then, you might get away with switching fonts at runtime (see "Can
424     I switch the fonts at runtime?" later in this document).
425    
426 root 1.50 How can I make mplayer display video correctly?
427     We are working on it, in the meantime, as a workaround, use something
428     like:
429    
430     urxvt -b 600 -geometry 20x1 -e sh -c 'mplayer -wid $WINDOWID file...'
431    
432 root 1.42 Keyboard, Mouse & User Interaction
433     The new selection selects pieces that are too big, how can I select single words?
434     If you want to select e.g. alphanumeric words, you can use the following
435     setting:
436    
437     URxvt.selection.pattern-0: ([[:word:]]+)
438    
439     If you click more than twice, the selection will be extended more and
440     more.
441    
442     To get a selection that is very similar to the old code, try this
443     pattern:
444    
445     URxvt.selection.pattern-0: ([^"&'()*,;<=>?@[\\\\]^`{|})]+)
446    
447 root 1.53 Please also note that the *LeftClick Shift-LeftClick* combination also
448 root 1.42 selects words like the old code.
449    
450     I don't like the new selection/popups/hotkeys/perl, how do I change/disable it?
451     You can disable the perl extension completely by setting the
452     perl-ext-common resource to the empty string, which also keeps
453     rxvt-unicode from initialising perl, saving memory.
454    
455     If you only want to disable specific features, you first have to
456     identify which perl extension is responsible. For this, read the section
457     PREPACKAGED EXTENSIONS in the urxvtperl(3) manpage. For example, to
458     disable the selection-popup and option-popup, specify this
459     perl-ext-common resource:
460    
461     URxvt.perl-ext-common: default,-selection-popup,-option-popup
462    
463     This will keep the default extensions, but disable the two popup
464     extensions. Some extensions can also be configured, for example,
465     scrollback search mode is triggered by M-s. You can move it to any other
466     combination either by setting the searchable-scrollback resource:
467    
468     URxvt.searchable-scrollback: CM-s
469    
470     The cursor moves when selecting text in the current input line, how do I switch this off?
471     See next entry.
472    
473     During rlogin/ssh/telnet/etc. sessions, clicking near the cursor outputs strange escape sequences, how do I fix this?
474     These are caused by the "readline" perl extension. Under normal
475     circumstances, it will move your cursor around when you click into the
476     line that contains it. It tries hard not to do this at the wrong moment,
477     but when running a program that doesn't parse cursor movements or in
478     some cases during rlogin sessions, it fails to detect this properly.
479    
480 root 1.43 You can permanently switch this feature off by disabling the "readline"
481 root 1.42 extension:
482    
483     URxvt.perl-ext-common: default,-readline
484    
485     My numerical keypad acts weird and generates differing output?
486     Some Debian GNUL/Linux users seem to have this problem, although no
487     specific details were reported so far. It is possible that this is
488 root 1.43 caused by the wrong "TERM" setting, although the details of whether and
489 root 1.42 how this can happen are unknown, as "TERM=rxvt" should offer a
490     compatible keymap. See the answer to the previous question, and please
491     report if that helped.
492    
493     My Compose (Multi_key) key is no longer working.
494     The most common causes for this are that either your locale is not set
495     correctly, or you specified a preeditStyle that is not supported by your
496     input method. For example, if you specified OverTheSpot and your input
497     method (e.g. the default input method handling Compose keys) does not
498     support this (for instance because it is not visual), then rxvt-unicode
499     will continue without an input method.
500    
501     In this case either do not specify a preeditStyle or specify more than
502     one pre-edit style, such as OverTheSpot,Root,None.
503    
504 root 1.57 If it still doesn't work, then maybe your input method doesn't support
505     compose sequences - to fall back to the built-in one, make sure you
506     don't specify an input method via "-im" or "XMODIFIERS".
507    
508 root 1.42 I cannot type "Ctrl-Shift-2" to get an ASCII NUL character due to ISO 14755
509     Either try "Ctrl-2" alone (it often is mapped to ASCII NUL even on
510     international keyboards) or simply use ISO 14755 support to your
511     advantage, typing <Ctrl-Shift-0> to get a ASCII NUL. This works for
512     other codes, too, such as "Ctrl-Shift-1-d" to type the default telnet
513     escape character and so on.
514    
515     Mouse cut/paste suddenly no longer works.
516     Make sure that mouse reporting is actually turned off since killing some
517     editors prematurely may leave the mouse in mouse report mode. I've heard
518     that tcsh may use mouse reporting unless it otherwise specified. A quick
519     check is to see if cut/paste works when the Alt or Shift keys are
520     depressed.
521    
522     What's with the strange Backspace/Delete key behaviour?
523 root 1.43 Assuming that the physical Backspace key corresponds to the Backspace
524 root 1.42 keysym (not likely for Linux ... see the following question) there are
525     two standard values that can be used for Backspace: "^H" and "^?".
526    
527     Historically, either value is correct, but rxvt-unicode adopts the
528 root 1.47 debian policy of using "^?" when unsure, because it's the one and only
529 root 1.42 correct choice :).
530    
531     Rxvt-unicode tries to inherit the current stty settings and uses the
532     value of `erase' to guess the value for backspace. If rxvt-unicode
533     wasn't started from a terminal (say, from a menu or by remote shell),
534     then the system value of `erase', which corresponds to CERASE in
535     <termios.h>, will be used (which may not be the same as your stty
536     setting).
537    
538     For starting a new rxvt-unicode:
539    
540     # use Backspace = ^H
541     $ stty erase ^H
542     $ urxvt
543    
544     # use Backspace = ^?
545     $ stty erase ^?
546     $ urxvt
547    
548     Toggle with "ESC [ 36 h" / "ESC [ 36 l".
549    
550     For an existing rxvt-unicode:
551    
552     # use Backspace = ^H
553     $ stty erase ^H
554     $ echo -n "^[[36h"
555    
556     # use Backspace = ^?
557     $ stty erase ^?
558     $ echo -n "^[[36l"
559    
560     This helps satisfy some of the Backspace discrepancies that occur, but
561     if you use Backspace = "^H", make sure that the termcap/terminfo value
562     properly reflects that.
563    
564     The Delete key is a another casualty of the ill-defined Backspace
565     problem. To avoid confusion between the Backspace and Delete keys, the
566     Delete key has been assigned an escape sequence to match the vt100 for
567     Execute ("ESC [ 3 ~") and is in the supplied termcap/terminfo.
568    
569     Some other Backspace problems:
570    
571     some editors use termcap/terminfo, some editors (vim I'm told) expect
572     Backspace = ^H, GNU Emacs (and Emacs-like editors) use ^H for help.
573    
574     Perhaps someday this will all be resolved in a consistent manner.
575    
576     I don't like the key-bindings. How do I change them?
577     There are some compile-time selections available via configure. Unless
578     you have run "configure" with the "--disable-resources" option you can
579     use the `keysym' resource to alter the keystrings associated with
580     keysyms.
581    
582     Here's an example for a URxvt session started using "urxvt -name URxvt"
583    
584     URxvt.keysym.Home: \033[1~
585     URxvt.keysym.End: \033[4~
586     URxvt.keysym.C-apostrophe: \033<C-'>
587     URxvt.keysym.C-slash: \033<C-/>
588     URxvt.keysym.C-semicolon: \033<C-;>
589     URxvt.keysym.C-grave: \033<C-`>
590     URxvt.keysym.C-comma: \033<C-,>
591     URxvt.keysym.C-period: \033<C-.>
592     URxvt.keysym.C-0x60: \033<C-`>
593     URxvt.keysym.C-Tab: \033<C-Tab>
594     URxvt.keysym.C-Return: \033<C-Return>
595     URxvt.keysym.S-Return: \033<S-Return>
596     URxvt.keysym.S-space: \033<S-Space>
597     URxvt.keysym.M-Up: \033<M-Up>
598     URxvt.keysym.M-Down: \033<M-Down>
599     URxvt.keysym.M-Left: \033<M-Left>
600     URxvt.keysym.M-Right: \033<M-Right>
601     URxvt.keysym.M-C-0: list \033<M-C- 0123456789 >
602     URxvt.keysym.M-C-a: list \033<M-C- abcdefghijklmnopqrstuvwxyz >
603     URxvt.keysym.F12: command:\033]701;zh_CN.GBK\007
604    
605     See some more examples in the documentation for the keysym resource.
606    
607     I'm using keyboard model XXX that has extra Prior/Next/Insert keys. How do I make use of them? For example, the Sun Keyboard type 4 has the following map
608     KP_Insert == Insert
609     F22 == Print
610     F27 == Home
611     F29 == Prior
612     F33 == End
613     F35 == Next
614    
615     Rather than have rxvt-unicode try to accommodate all the various
616     possible keyboard mappings, it is better to use `xmodmap' to remap the
617     keys as required for your particular machine.
618    
619     Terminal Configuration
620     Can I see a typical configuration?
621     The default configuration tries to be xterm-like, which I don't like
622     that much, but it's least surprise to regular users.
623    
624     As a rxvt or rxvt-unicode user, you are practically supposed to invest
625     time into customising your terminal. To get you started, here is the
626     author's .Xdefaults entries, with comments on what they do. It's
627     certainly not *typical*, but what's typical...
628    
629     URxvt.cutchars: "()*,<>[]{}|'
630     URxvt.print-pipe: cat >/tmp/xxx
631    
632     These are just for testing stuff.
633    
634     URxvt.imLocale: ja_JP.UTF-8
635     URxvt.preeditType: OnTheSpot,None
636    
637     This tells rxvt-unicode to use a special locale when communicating with
638     the X Input Method, and also tells it to only use the OnTheSpot pre-edit
639     type, which requires the "xim-onthespot" perl extension but rewards me
640     with correct-looking fonts.
641    
642     URxvt.perl-lib: /root/lib/urxvt
643     URxvt.perl-ext-common: default,selection-autotransform,selection-pastebin,xim-onthespot,remote-clipboard
644     URxvt.selection.pattern-0: ( at .*? line \\d+)
645     URxvt.selection.pattern-1: ^(/[^:]+):\
646     URxvt.selection-autotransform.0: s/^([^:[:space:]]+):(\\d+):?$/:e \\Q$1\\E\\x0d:$2\\x0d/
647     URxvt.selection-autotransform.1: s/^ at (.*?) line (\\d+)$/:e \\Q$1\\E\\x0d:$2\\x0d/
648    
649     This is my perl configuration. The first two set the perl library
650     directory and also tells urxvt to use a large number of extensions. I
651     develop for myself mostly, so I actually use most of the extensions I
652     write.
653    
654     The selection stuff mainly makes the selection perl-error-message aware
655 root 1.43 and tells it to convert perl error messages into vi-commands to load the
656 root 1.58 relevant file and go to the error line number.
657 root 1.42
658     URxvt.scrollstyle: plain
659     URxvt.secondaryScroll: true
660    
661     As the documentation says: plain is the preferred scrollbar for the
662 root 1.43 author. The "secondaryScroll" configures urxvt to scroll in full-screen
663     apps, like screen, so lines scrolled out of screen end up in urxvt's
664 root 1.42 scrollback buffer.
665    
666     URxvt.background: #000000
667     URxvt.foreground: gray90
668     URxvt.color7: gray90
669     URxvt.colorBD: #ffffff
670     URxvt.cursorColor: #e0e080
671     URxvt.throughColor: #8080f0
672     URxvt.highlightColor: #f0f0f0
673    
674     Some colours. Not sure which ones are being used or even non-defaults,
675     but these are in my .Xdefaults. Most notably, they set
676     foreground/background to light gray/black, and also make sure that the
677     colour 7 matches the default foreground colour.
678    
679     URxvt.underlineColor: yellow
680    
681     Another colour, makes underline lines look different. Sometimes hurts,
682     but is mostly a nice effect.
683    
684     URxvt.geometry: 154x36
685     URxvt.loginShell: false
686     URxvt.meta: ignore
687     URxvt.utmpInhibit: true
688    
689     Uh, well, should be mostly self-explanatory. By specifying some defaults
690     manually, I can quickly switch them for testing.
691    
692     URxvt.saveLines: 8192
693    
694     A large scrollback buffer is essential. Really.
695    
696     URxvt.mapAlert: true
697    
698     The only case I use it is for my IRC window, which I like to keep
699     iconified till people msg me (which beeps).
700    
701     URxvt.visualBell: true
702    
703     The audible bell is often annoying, especially when in a crowd.
704    
705     URxvt.insecure: true
706    
707     Please don't hack my mutt! Ooops...
708    
709     URxvt.pastableTabs: false
710    
711     I once thought this is a great idea.
712    
713     urxvt.font: 9x15bold,\
714     -misc-fixed-bold-r-normal--15-140-75-75-c-90-iso10646-1,\
715     -misc-fixed-medium-r-normal--15-140-75-75-c-90-iso10646-1, \
716     [codeset=JISX0208]xft:Kochi Gothic, \
717     xft:Bitstream Vera Sans Mono:autohint=true, \
718     xft:Code2000:antialias=false
719     urxvt.boldFont: -xos4-terminus-bold-r-normal--14-140-72-72-c-80-iso8859-15
720     urxvt.italicFont: xft:Bitstream Vera Sans Mono:italic:autohint=true
721     urxvt.boldItalicFont: xft:Bitstream Vera Sans Mono:bold:italic:autohint=true
722    
723     I wrote rxvt-unicode to be able to specify fonts exactly. So don't be
724 root 1.43 overwhelmed. A special note: the "9x15bold" mentioned above is actually
725 root 1.42 the version from XFree-3.3, as XFree-4 replaced it by a totally
726     different font (different glyphs for ";" and many other harmless
727     characters), while the second font is actually the "9x15bold" from
728     XFree4/XOrg. The bold version has less chars than the medium version, so
729 root 1.43 I use it for rare characters, too. When editing sources with vim, I use
730 root 1.42 italic for comments and other stuff, which looks quite good with
731     Bitstream Vera anti-aliased.
732    
733     Terminus is a quite bad font (many very wrong glyphs), but for most of
734     my purposes, it works, and gives a different look, as my normal
735     (Non-bold) font is already bold, and I want to see a difference between
736     bold and normal fonts.
737    
738     Please note that I used the "urxvt" instance name and not the "URxvt"
739 root 1.58 class name. That is because I use different configs for different
740 root 1.42 purposes, for example, my IRC window is started with "-name IRC", and
741     uses these defaults:
742    
743     IRC*title: IRC
744     IRC*geometry: 87x12+535+542
745     IRC*saveLines: 0
746     IRC*mapAlert: true
747     IRC*font: suxuseuro
748     IRC*boldFont: suxuseuro
749     IRC*colorBD: white
750     IRC*keysym.M-C-1: command:\033]710;suxuseuro\007\033]711;suxuseuro\007
751     IRC*keysym.M-C-2: command:\033]710;9x15bold\007\033]711;9x15bold\007
752    
753 root 1.57 "Alt-Ctrl-1" and "Alt-Ctrl-2" switch between two different font sizes.
754 root 1.42 "suxuseuro" allows me to keep an eye (and actually read) stuff while
755     keeping a very small window. If somebody pastes something complicated
756     (e.g. japanese), I temporarily switch to a larger font.
757    
758     The above is all in my ".Xdefaults" (I don't use ".Xresources" nor
759     "xrdb"). I also have some resources in a separate ".Xdefaults-hostname"
760     file for different hosts, for example, on ym main desktop, I use:
761    
762     URxvt.keysym.C-M-q: command:\033[3;5;5t
763     URxvt.keysym.C-M-y: command:\033[3;5;606t
764     URxvt.keysym.C-M-e: command:\033[3;1605;5t
765     URxvt.keysym.C-M-c: command:\033[3;1605;606t
766     URxvt.keysym.C-M-p: perl:test
767    
768     The first for keysym definitions allow me to quickly bring some windows
769     in the layout I like most. Ion users might start laughing but will stop
770     immediately when I tell them that I use my own Fvwm2 module for much the
771     same effect as Ion provides, and I only very rarely use the above key
772     combinations :->
773    
774     Why doesn't rxvt-unicode read my resources?
775     Well, why, indeed? It does, in a way very similar to other X
776     applications. Most importantly, this means that if you or your OS loads
777     resources into the X display (the right way to do it), rxvt-unicode will
778     ignore any resource files in your home directory. It will only read
779     $HOME/.Xdefaults when no resources are attached to the display.
780    
781     If you have or use an $HOME/.Xresources file, chances are that resources
782     are loaded into your X-server. In this case, you have to re-login after
783     every change (or run xrdb -merge $HOME/.Xresources).
784    
785     Also consider the form resources have to use:
786    
787     URxvt.resource: value
788    
789     If you want to use another form (there are lots of different ways of
790 root 1.43 specifying resources), make sure you understand whether and why it
791     works. If unsure, use the form above.
792 root 1.42
793     When I log-in to another system it tells me about missing terminfo data?
794     The terminal description used by rxvt-unicode is not as widely available
795     as that for xterm, or even rxvt (for which the same problem often
796     arises).
797    
798     The correct solution for this problem is to install the terminfo, this
799 root 1.57 can be done by simply installing rxvt-unicode on the remote system as
800     well (in case you have a nice package manager ready), or you can install
801     the terminfo database manually like this (with ncurses infocmp. works as
802     user and root):
803 root 1.42
804     REMOTE=remotesystem.domain
805 root 1.44 infocmp rxvt-unicode | ssh $REMOTE "mkdir -p .terminfo && cat >/tmp/ti && tic /tmp/ti"
806 root 1.42
807 root 1.44 One some systems you might need to set $TERMINFO to the full path of
808     $HOME/.terminfo for this to work.
809    
810 root 1.42 If you cannot or do not want to do this, then you can simply set
811     "TERM=rxvt" or even "TERM=xterm", and live with the small number of
812     problems arising, which includes wrong keymapping, less and different
813     colours and some refresh errors in fullscreen applications. It's a nice
814     quick-and-dirty workaround for rare cases, though.
815    
816     If you always want to do this (and are fine with the consequences) you
817     can either recompile rxvt-unicode with the desired TERM value or use a
818     resource to set it:
819    
820     URxvt.termName: rxvt
821    
822     If you don't plan to use rxvt (quite common...) you could also replace
823     the rxvt terminfo file with the rxvt-unicode one and use "TERM=rxvt".
824    
825 root 1.57 nano fails with "Error opening terminal: rxvt-unicode"
826     This exceptionally confusing and useless error message is printed by
827     nano when it can't find the terminfo database. Nothing is wrong with
828     your terminal, read the previous answer for a solution.
829    
830 root 1.42 "tic" outputs some error when compiling the terminfo entry.
831     Most likely it's the empty definition for "enacs=". Just replace it by
832     "enacs=\E[0@" and try again.
833    
834     "bash"'s readline does not work correctly under urxvt.
835     See next entry.
836    
837     I need a termcap file entry.
838     One reason you might want this is that some distributions or operating
839     systems still compile some programs using the long-obsoleted termcap
840     library (Fedora Core's bash is one example) and rely on a termcap entry
841     for "rxvt-unicode".
842    
843 root 1.43 You could use rxvt's termcap entry with reasonable results in many
844     cases. You can also create a termcap entry by using terminfo's infocmp
845     program like this:
846 root 1.42
847     infocmp -C rxvt-unicode
848    
849 root 1.55 Or you could use the termcap entry in doc/etc/rxvt-unicode.termcap,
850     generated by the command above.
851 root 1.42
852     Why does "ls" no longer have coloured output?
853     The "ls" in the GNU coreutils unfortunately doesn't use terminfo to
854 root 1.43 decide whether a terminal has colour, but uses its own configuration
855 root 1.42 file. Needless to say, "rxvt-unicode" is not in its default file (among
856     with most other terminals supporting colour). Either add:
857    
858     TERM rxvt-unicode
859    
860     to "/etc/DIR_COLORS" or simply add:
861    
862     alias ls='ls --color=auto'
863    
864     to your ".profile" or ".bashrc".
865    
866     Why doesn't vim/emacs etc. use the 88 colour mode?
867     See next entry.
868    
869     Why doesn't vim/emacs etc. make use of italic?
870     See next entry.
871    
872     Why are the secondary screen-related options not working properly?
873     Make sure you are using "TERM=rxvt-unicode". Some pre-packaged
874     distributions (most notably Debian GNU/Linux) break rxvt-unicode by
875     setting "TERM" to "rxvt", which doesn't have these extra features.
876     Unfortunately, some of these (most notably, again, Debian GNU/Linux)
877     furthermore fail to even install the "rxvt-unicode" terminfo file, so
878     you will need to install it on your own (See the question When I log-in
879     to another system it tells me about missing terminfo data? on how to do
880     this).
881    
882     Encoding / Locale / Input Method Issues
883     Rxvt-unicode does not seem to understand the selected encoding?
884     See next entry.
885    
886     Unicode does not seem to work?
887     If you encounter strange problems like typing an accented character but
888     getting two unrelated other characters or similar, or if program output
889     is subtly garbled, then you should check your locale settings.
890    
891     Rxvt-unicode must be started with the same "LC_CTYPE" setting as the
892 root 1.46 programs running in it. Often rxvt-unicode is started in the "C" locale,
893     while the login script running within the rxvt-unicode window changes
894     the locale to something else, e.g. "en_GB.UTF-8". Needless to say, this
895     is not going to work, and is the most common cause for problems.
896 root 1.42
897     The best thing is to fix your startup environment, as you will likely
898     run into other problems. If nothing works you can try this in your
899     .profile.
900    
901 root 1.46 printf '\33]701;%s\007' "$LC_CTYPE" # $LANG or $LC_ALL are worth a try, too
902 root 1.42
903     If this doesn't work, then maybe you use a "LC_CTYPE" specification not
904     supported on your systems. Some systems have a "locale" command which
905     displays this (also, "perl -e0" can be used to check locale settings, as
906     it will complain loudly if it cannot set the locale). If it displays
907     something like:
908    
909     locale: Cannot set LC_CTYPE to default locale: ...
910    
911     Then the locale you specified is not supported on your system.
912    
913     If nothing works and you are sure that everything is set correctly then
914     you will need to remember a little known fact: Some programs just don't
915     support locales :(
916    
917     How does rxvt-unicode determine the encoding to use?
918     See next entry.
919    
920     Is there an option to switch encodings?
921     Unlike some other terminals, rxvt-unicode has no encoding switch, and no
922     specific "utf-8" mode, such as xterm. In fact, it doesn't even know
923     about UTF-8 or any other encodings with respect to terminal I/O.
924    
925     The reasons is that there exists a perfectly fine mechanism for
926     selecting the encoding, doing I/O and (most important) communicating
927     this to all applications so everybody agrees on character properties
928     such as width and code number. This mechanism is the *locale*.
929     Applications not using that info will have problems (for example,
930     "xterm" gets the width of characters wrong as it uses its own,
931     locale-independent table under all locales).
932    
933     Rxvt-unicode uses the "LC_CTYPE" locale category to select encoding. All
934     programs doing the same (that is, most) will automatically agree in the
935     interpretation of characters.
936    
937     Unfortunately, there is no system-independent way to select locales, nor
938     is there a standard on how locale specifiers will look like.
939    
940     On most systems, the content of the "LC_CTYPE" environment variable
941     contains an arbitrary string which corresponds to an already-installed
942     locale. Common names for locales are "en_US.UTF-8", "de_DE.ISO-8859-15",
943     "ja_JP.EUC-JP", i.e. "language_country.encoding", but other forms (i.e.
944     "de" or "german") are also common.
945    
946     Rxvt-unicode ignores all other locale categories, and except for the
947     encoding, ignores country or language-specific settings, i.e.
948     "de_DE.UTF-8" and "ja_JP.UTF-8" are the normally same to rxvt-unicode.
949    
950     If you want to use a specific encoding you have to make sure you start
951     rxvt-unicode with the correct "LC_CTYPE" category.
952    
953     Can I switch locales at runtime?
954     Yes, using an escape sequence. Try something like this, which sets
955     rxvt-unicode's idea of "LC_CTYPE".
956    
957     printf '\33]701;%s\007' ja_JP.SJIS
958    
959     See also the previous answer.
960    
961     Sometimes this capability is rather handy when you want to work in one
962     locale (e.g. "de_DE.UTF-8") but some programs don't support it (e.g.
963     UTF-8). For example, I use this script to start "xjdic", which first
964     switches to a locale supported by xjdic and back later:
965    
966     printf '\33]701;%s\007' ja_JP.SJIS
967     xjdic -js
968     printf '\33]701;%s\007' de_DE.UTF-8
969    
970     You can also use xterm's "luit" program, which usually works fine,
971     except for some locales where character width differs between program-
972     and rxvt-unicode-locales.
973    
974     I have problems getting my input method working.
975     Try a search engine, as this is slightly different for every input
976     method server.
977    
978     Here is a checklist:
979    
980     - Make sure your locale *and* the imLocale are supported on your OS.
981     Try "locale -a" or check the documentation for your OS.
982    
983     - Make sure your locale or imLocale matches a locale supported by your
984     XIM.
985     For example, kinput2 does not support UTF-8 locales, you should use
986     "ja_JP.EUC-JP" or equivalent.
987    
988     - Make sure your XIM server is actually running.
989     - Make sure the "XMODIFIERS" environment variable is set correctly when
990     *starting* rxvt-unicode.
991     When you want to use e.g. kinput2, it must be set to "@im=kinput2".
992 root 1.43 For scim, use "@im=SCIM". You can see what input method servers are
993 root 1.42 running with this command:
994    
995     xprop -root XIM_SERVERS
996    
997 root 1.54
998 root 1.42
999     My input method wants <some encoding> but I want UTF-8, what can I do?
1000     You can specify separate locales for the input method and the rest of
1001     the terminal, using the resource "imlocale":
1002    
1003     URxvt.imlocale: ja_JP.EUC-JP
1004    
1005     Now you can start your terminal with "LC_CTYPE=ja_JP.UTF-8" and still
1006     use your input method. Please note, however, that, depending on your
1007     Xlib version, you may not be able to input characters outside "EUC-JP"
1008     in a normal way then, as your input method limits you.
1009    
1010     Rxvt-unicode crashes when the X Input Method changes or exits.
1011     Unfortunately, this is unavoidable, as the XIM protocol is racy by
1012     design. Applications can avoid some crashes at the expense of memory
1013     leaks, and Input Methods can avoid some crashes by careful ordering at
1014     exit time. kinput2 (and derived input methods) generally succeeds, while
1015     SCIM (or similar input methods) fails. In the end, however, crashes
1016     cannot be completely avoided even if both sides cooperate.
1017    
1018     So the only workaround is not to kill your Input Method Servers.
1019    
1020     Operating Systems / Package Maintaining
1021     I am using Debian GNU/Linux and have a problem...
1022     The Debian GNU/Linux package of rxvt-unicode in sarge contains large
1023     patches that considerably change the behaviour of rxvt-unicode (but
1024     unfortunately this notice has been removed). Before reporting a bug to
1025     the original rxvt-unicode author please download and install the genuine
1026     version (<http://software.schmorp.de#rxvt-unicode>) and try to reproduce
1027     the problem. If you cannot, chances are that the problems are specific
1028     to Debian GNU/Linux, in which case it should be reported via the Debian
1029     Bug Tracking System (use "reportbug" to report the bug).
1030    
1031     For other problems that also affect the Debian package, you can and
1032     probably should use the Debian BTS, too, because, after all, it's also a
1033     bug in the Debian version and it serves as a reminder for other users
1034     that might encounter the same issue.
1035    
1036     I am maintaining rxvt-unicode for distribution/OS XXX, any recommendation?
1037     You should build one binary with the default options. configure now
1038     enables most useful options, and the trend goes to making them
1039 root 1.43 runtime-switchable, too, so there is usually no drawback to enabling
1040 root 1.42 them, except higher disk and possibly memory usage. The perl interpreter
1041     should be enabled, as important functionality (menus, selection, likely
1042     more in the future) depends on it.
1043    
1044 root 1.58 You should not overwrite the "perl-ext-common" and "perl-ext" resources
1045 root 1.42 system-wide (except maybe with "defaults"). This will result in useful
1046     behaviour. If your distribution aims at low memory, add an empty
1047     "perl-ext-common" resource to the app-defaults file. This will keep the
1048     perl interpreter disabled until the user enables it.
1049    
1050     If you can/want build more binaries, I recommend building a minimal one
1051     with "--disable-everything" (very useful) and a maximal one with
1052     "--enable-everything" (less useful, it will be very big due to a lot of
1053     encodings built-in that increase download times and are rarely used).
1054    
1055     I need to make it setuid/setgid to support utmp/ptys on my OS, is this safe?
1056     It should be, starting with release 7.1. You are encouraged to properly
1057     install urxvt with privileges necessary for your OS now.
1058    
1059     When rxvt-unicode detects that it runs setuid or setgid, it will fork
1060     into a helper process for privileged operations (pty handling on some
1061     systems, utmp/wtmp/lastlog handling on others) and drop privileges
1062     immediately. This is much safer than most other terminals that keep
1063     privileges while running (but is more relevant to urxvt, as it contains
1064     things as perl interpreters, which might be "helpful" to attackers).
1065    
1066     This forking is done as the very first within main(), which is very
1067     early and reduces possible bugs to initialisation code run before
1068     main(), or things like the dynamic loader of your system, which should
1069     result in very little risk.
1070    
1071     I am on FreeBSD and rxvt-unicode does not seem to work at all.
1072     Rxvt-unicode requires the symbol "__STDC_ISO_10646__" to be defined in
1073     your compile environment, or an implementation that implements it,
1074 root 1.43 whether it defines the symbol or not. "__STDC_ISO_10646__" requires that
1075 root 1.42 wchar_t is represented as unicode.
1076    
1077 root 1.43 As you might have guessed, FreeBSD does neither define this symbol nor
1078 root 1.42 does it support it. Instead, it uses its own internal representation of
1079     wchar_t. This is, of course, completely fine with respect to standards.
1080    
1081     However, that means rxvt-unicode only works in "POSIX", "ISO-8859-1" and
1082 root 1.55 "UTF-8" locales under FreeBSD (which all use Unicode as wchar_t).
1083 root 1.42
1084     "__STDC_ISO_10646__" is the only sane way to support multi-language apps
1085     in an OS, as using a locale-dependent (and non-standardized)
1086     representation of wchar_t makes it impossible to convert between wchar_t
1087     (as used by X11 and your applications) and any other encoding without
1088     implementing OS-specific-wrappers for each and every locale. There
1089     simply are no APIs to convert wchar_t into anything except the current
1090     locale encoding.
1091    
1092     Some applications (such as the formidable mlterm) work around this by
1093     carrying their own replacement functions for character set handling with
1094     them, and either implementing OS-dependent hacks or doing multiple
1095     conversions (which is slow and unreliable in case the OS implements
1096     encodings slightly different than the terminal emulator).
1097    
1098     The rxvt-unicode author insists that the right way to fix this is in the
1099     system libraries once and for all, instead of forcing every app to carry
1100     complete replacements for them :)
1101    
1102     How can I use rxvt-unicode under cygwin?
1103     rxvt-unicode should compile and run out of the box on cygwin, using the
1104     X11 libraries that come with cygwin. libW11 emulation is no longer
1105     supported (and makes no sense, either, as it only supported a single
1106     font). I recommend starting the X-server in "-multiwindow" or
1107     "-rootless" mode instead, which will result in similar look&feel as the
1108     old libW11 emulation.
1109    
1110     At the time of this writing, cygwin didn't seem to support any
1111     multi-byte encodings (you might try "LC_CTYPE=C-UTF-8"), so you are
1112     likely limited to 8-bit encodings.
1113    
1114 root 1.49 Character widths are not correct.
1115     urxvt uses the system wcwidth function to know the information about the
1116     width of characters, so on systems with incorrect locale data you will
1117     likely get bad results. Two notorious examples are Solaris 9, where
1118     single-width characters like U+2514 are reported as double-width, and
1119     Darwin 8, where combining chars are reported having width 1.
1120    
1121     The solution is to upgrade your system or switch to a better one. A
1122     possibly working workaround is to use a wcwidth implementation like
1123    
1124     http://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
1125