1 Known Problems with GNU Emacs
3 Copyright (C) 1987-1989, 1993-1999, 2001-2016 Free Software Foundation,
5 See the end of the file for license conditions.
8 This file describes various problems that have been encountered
9 in compiling, installing and running GNU Emacs. Try doing C-c C-t
10 and browsing through the outline headers. (See C-h m for help on
11 Outline mode.) Information about systems that are no longer supported,
12 and old Emacs releases, has been removed. Consult older versions of
13 this file if you are interested in that information.
15 * Mule-UCS doesn't work in Emacs 23 onwards
17 It's completely redundant now, as far as we know.
19 * Emacs startup failures
21 ** Emacs fails to start, complaining about missing fonts.
23 A typical error message might be something like
25 No fonts match ‘-*-fixed-medium-r-*--6-*-*-*-*-*-iso8859-1’
27 This happens because some X resource specifies a bad font family for
28 Emacs to use. The possible places where this specification might be are:
30 - in the X server resources database, often initialized from
31 ~/.Xresources (use $ xrdb -query to find out the current state)
33 - in your ~/.Xdefaults file
35 - client-side X resource file, such as ~/Emacs or
36 /usr/share/X11/app-defaults/Emacs
38 One of these files might have bad or malformed specification of a
39 fontset that Emacs should use. To fix the problem, you need to find
40 the problematic line(s) and correct them.
42 After correcting ~/.Xresources, the new data has to be merged into the
43 X server resources database. Depending on the circumstances, the
44 following command may do the trick. See xrdb(1) for more information.
46 $ xrdb -merge ~/.Xresources
48 ** Emacs aborts while starting up, only when run without X.
50 This problem often results from compiling Emacs with GCC when GCC was
51 installed incorrectly. The usual error in installing GCC is to
52 specify --includedir=/usr/include. Installation of GCC makes
53 corrected copies of the system header files. GCC is supposed to use
54 the corrected copies in preference to the original system headers.
55 Specifying --includedir=/usr/include causes the original system header
56 files to be used. On some systems, the definition of ioctl in the
57 original system header files is invalid for ANSI C and causes Emacs
60 The fix is to reinstall GCC, and this time do not specify --includedir
61 when you configure it. Then recompile Emacs. Specifying --includedir
62 is appropriate only in very special cases and it should *never* be the
63 same directory where system header files are kept.
65 ** Emacs does not start, complaining that it cannot open termcap database file.
67 If your system uses Terminfo rather than termcap (most modern
68 systems do), this could happen if the proper version of
69 ncurses is not visible to the Emacs configure script (i.e. it
70 cannot be found along the usual path the linker looks for
71 libraries). It can happen because your version of ncurses is
72 obsolete, or is available only in form of binaries.
74 The solution is to install an up-to-date version of ncurses in
75 the developer's form (header files, static libraries and
76 symbolic links); in some GNU/Linux distributions (e.g. Debian)
77 it constitutes a separate package.
79 ** Emacs 20 and later fails to load Lisp files at startup.
81 The typical error message might be like this:
83 "Cannot open load file: fontset"
85 This could happen if you compress the file lisp/subdirs.el. That file
86 tells Emacs what are the directories where it should look for Lisp
87 files. Emacs cannot work with subdirs.el compressed, since the
88 Auto-compress mode it needs for this will not be loaded until later,
89 when your .emacs file is processed. (The package 'fontset.el' is
90 required to set up fonts used to display text on window systems, and
91 it's loaded very early in the startup procedure.)
93 Similarly, any other .el file for which there's no corresponding .elc
94 file could fail to load if it is compressed.
96 The solution is to uncompress all .el files that don't have a .elc file.
98 Another possible reason for such failures is stale *.elc files
99 lurking somewhere on your load-path -- see the next section.
101 ** Emacs prints an error at startup after upgrading from an earlier version.
103 An example of such an error is:
105 x-complement-fontset-spec: "Wrong type argument: stringp, nil"
107 This can be another symptom of stale *.elc files in your load-path.
108 The following command will print any duplicate Lisp files that are
109 present in load-path:
111 emacs -batch -f list-load-path-shadows
113 If this command prints any file names, some of these files are stale,
114 and should be deleted or their directories removed from your
119 ** Emacs crashes when running in a terminal, if compiled with GCC 4.5.0
121 This version of GCC is buggy: see
123 http://debbugs.gnu.org/6031
124 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43904
126 You can work around this error in gcc-4.5 by omitting sibling call
127 optimization. To do this, configure Emacs with
129 CFLAGS="-g -O2 -fno-optimize-sibling-calls" ./configure
131 ** Emacs compiled with GCC 4.6.1 crashes on MS-Windows when C-g is pressed
133 This is known to happen when Emacs is compiled with MinGW GCC 4.6.1
134 with the -O2 option (which is the default in the Windows build). The
135 reason is a bug in MinGW GCC 4.6.1; to work around, either add the
136 '-fno-omit-frame-pointer' switch to GCC or compile without
137 optimizations ('--no-opt' switch to the configure.bat script).
139 ** Emacs crashes in x-popup-dialog.
141 This can happen if the dialog widget cannot find the font it wants to
142 use. You can work around the problem by specifying another font with
143 an X resource--for example, 'Emacs.dialog*.font: 9x15' (or any font that
144 happens to exist on your X server).
146 ** Emacs crashes when you use Bibtex mode.
148 This happens if your system puts a small limit on stack size. You can
149 prevent the problem by using a suitable shell command (often 'ulimit')
150 to raise the stack size limit before you run Emacs.
152 Patches to raise the stack size limit automatically in 'main'
153 (src/emacs.c) on various systems would be greatly appreciated.
155 ** Error message 'Symbol’s value as variable is void: x', followed by
156 a segmentation fault and core dump.
158 This has been tracked to a bug in tar! People report that tar erroneously
159 added a line like this at the beginning of files of Lisp code:
161 x FILENAME, N bytes, B tape blocks
163 If your tar has this problem, install GNU tar--if you can manage to
166 ** Emacs can crash when displaying PNG images with transparency.
168 This is due to a bug introduced in ImageMagick 6.8.2-3. The bug should
169 be fixed in ImageMagick 6.8.3-10. See <URL:http://debbugs.gnu.org/13867>.
171 ** Crashes when displaying GIF images in Emacs built with version
172 libungif-4.1.0 are resolved by using version libungif-4.1.0b1.
173 Configure checks for the correct version, but this problem could occur
174 if a binary built against a shared libungif is run on a system with an
177 ** Emacs aborts inside the function 'tparam1'.
179 This can happen if Emacs was built without terminfo support, but the
180 terminal's capabilities use format that is only supported by terminfo.
181 If your system has ncurses installed, this might happen if your
182 version of ncurses is broken; upgrading to a newer version of ncurses
183 and reconfiguring and rebuilding Emacs should solve this.
185 All modern systems support terminfo, so even if ncurses is not the
186 problem, you should look for a way to configure Emacs so that it uses
189 ** Emacs crashes when using some version of the Exceed X server.
191 Upgrading to a newer version of Exceed has been reported to prevent
192 these crashes. You should consider switching to a free X server, such
193 as Xming or Cygwin/X.
195 ** Emacs crashes with SIGSEGV in XtInitializeWidgetClass.
197 It crashes on X, but runs fine when called with option "-nw".
199 This has been observed when Emacs is linked with GNU ld but without passing
200 the -z nocombreloc flag. Emacs normally knows to pass the -z nocombreloc
201 flag when needed, so if you come across a situation where the flag is
202 necessary but missing, please report it via M-x report-emacs-bug.
204 On platforms such as Solaris, you can also work around this problem by
205 configuring your compiler to use the native linker instead of GNU ld.
207 ** When Emacs is compiled with Gtk+, closing a display kills Emacs.
209 There is a long-standing bug in GTK that prevents it from recovering
210 from disconnects: http://bugzilla.gnome.org/show_bug.cgi?id=85715.
212 Thus, for instance, when Emacs is run as a server on a text terminal,
213 and an X frame is created, and the X server for that frame crashes or
214 exits unexpectedly, Emacs must exit to prevent a GTK error that would
215 result in an endless loop.
217 If you need Emacs to be able to recover from closing displays, compile
218 it with the Lucid toolkit instead of GTK.
220 ** Emacs crashes when you try to view a file with complex characters.
222 For example, the etc/HELLO file (as shown by C-h h).
223 The message "symbol lookup error: /usr/bin/emacs: undefined symbol: OTF_open"
224 is shown in the terminal from which you launched Emacs.
225 This problem only happens when you use a graphical display (ie not
226 with -nw) and compiled Emacs with the "libotf" library for complex
229 This problem occurs because unfortunately there are two libraries
230 called "libotf". One is the library for handling OpenType fonts,
231 http://www.m17n.org/libotf/, which is the one that Emacs expects.
232 The other is a library for Open Trace Format, and is used by some
233 versions of the MPI message passing interface for parallel
236 For example, on RHEL6 GNU/Linux, the OpenMPI rpm provides a version
237 of "libotf.so" in /usr/lib/openmpi/lib. This directory is not
238 normally in the ld search path, but if you want to use OpenMPI,
239 you must issue the command "module load openmpi". This adds
240 /usr/lib/openmpi/lib to LD_LIBRARY_PATH. If you then start Emacs from
241 the same shell, you will encounter this crash.
242 Ref: <URL:https://bugzilla.redhat.com/show_bug.cgi?id=844776>
244 There is no good solution to this problem if you need to use both
245 OpenMPI and Emacs with libotf support. The best you can do is use a
246 wrapper shell script (or function) "emacs" that removes the offending
247 element from LD_LIBRARY_PATH before starting emacs proper.
248 Or you could recompile Emacs with an -Wl,-rpath option that
249 gives the location of the correct libotf.
251 * General runtime problems
255 *** Changes made to .el files do not take effect.
257 You may have forgotten to recompile them into .elc files.
258 Then the old .elc files will be loaded, and your changes
259 will not be seen. To fix this, do M-x byte-recompile-directory
260 and specify the directory that contains the Lisp files.
262 Emacs prints a warning when loading a .elc file which is older
263 than the corresponding .el file.
265 Alternatively, if you set the option 'load-prefer-newer' non-nil,
266 Emacs will load whichever version of a file is the newest.
268 *** Watch out for the EMACSLOADPATH environment variable
270 EMACSLOADPATH overrides which directories the function "load" will search.
272 If you observe strange problems, check for this variable in your
275 *** Using epop3.el package causes Emacs to signal an error.
277 The error message might be something like this:
279 "Lisp nesting exceeds max-lisp-eval-depth"
281 This happens because epop3 redefines the function gethash, which is a
282 built-in primitive beginning with Emacs 21.1. We don't have a patch
283 for epop3 to fix it, but perhaps a newer version of epop3 corrects that.
285 *** Buffers from 'with-output-to-temp-buffer' get set up in Help mode.
287 Changes in Emacs 20.4 to the hooks used by that function cause
288 problems for some packages, specifically BBDB. See the function's
289 documentation for the hooks involved. BBDB 2.00.06 fixes the problem.
291 *** The Hyperbole package causes *Help* buffers not to be displayed in
292 Help mode due to setting 'temp-buffer-show-hook' rather than using
293 'add-hook'. Using '(add-hook 'temp-buffer-show-hook 'help-mode-finish)'
294 after loading Hyperbole should fix this.
298 *** Unable to enter the M-| key on some German keyboards.
299 Some users have reported that M-| suffers from "keyboard ghosting".
300 This can't be fixed by Emacs, as the keypress never gets passed to it
301 at all (as can be verified using "xev"). You can work around this by
302 typing 'ESC |' instead.
304 *** "Compose Character" key does strange things when used as a Meta key.
306 If you define one key to serve as both Meta and Compose Character, you
307 will get strange results. In previous Emacs versions, this "worked"
308 in that the key acted as Meta--that's because the older Emacs versions
309 did not try to support Compose Character. Now Emacs tries to do
310 character composition in the standard X way. This means that you
311 must pick one meaning or the other for any given key.
313 You can use both functions (Meta, and Compose Character) if you assign
314 them to two different keys.
316 *** C-z just refreshes the screen instead of suspending Emacs.
318 You are probably using a shell that doesn't support job control, even
319 though the system itself is capable of it. Either use a different shell,
320 or set the variable 'cannot-suspend' to a non-nil value.
322 ** Mailers and other helper programs
324 *** movemail compiled with POP support can't connect to the POP server.
326 Make sure that the 'pop' entry in /etc/services, or in the services
327 NIS map if your machine uses NIS, has the same port number as the
328 entry on the POP server. A common error is for the POP server to be
329 listening on port 110, the assigned port for the POP3 protocol, while
330 the client is trying to connect on port 109, the assigned port for the
333 *** RMAIL gets error getting new mail.
335 RMAIL gets new mail from /usr/spool/mail/$USER using a program
336 called 'movemail'. This program interlocks with /bin/mail using
337 the protocol defined by /bin/mail.
339 There are two different protocols in general use. One of them uses
340 the 'flock' system call. The other involves creating a lock file;
341 'movemail' must be able to write in /usr/spool/mail in order to do
342 this. You control which one is used by defining, or not defining,
343 the macro MAIL_USE_FLOCK in config.h.
344 IF YOU DON'T USE THE FORM OF INTERLOCKING THAT IS NORMAL ON YOUR
345 SYSTEM, YOU CAN LOSE MAIL!
347 If your system uses the lock file protocol, and fascist restrictions
348 prevent ordinary users from writing the lock files in /usr/spool/mail,
349 you may need to make 'movemail' setgid to a suitable group such as
350 'mail'. To do this, use the following commands (as root) after doing the
356 Installation normally copies movemail from the build directory to an
357 installation directory which is usually under /usr/local/lib. The
358 installed copy of movemail is usually in the directory
359 /usr/local/lib/emacs/VERSION/TARGET. You must change the group and
360 mode of the installed copy; changing the group and mode of the build
361 directory copy is ineffective.
363 *** rcs2log gives you the awk error message "too many fields".
365 This is due to an arbitrary limit in certain versions of awk.
366 The solution is to use gawk (GNU awk).
368 ** Problems with hostname resolution
370 *** Emacs does not know your host's fully-qualified domain name.
372 For example, (system-name) returns some variation on
373 "localhost.localdomain", rather the name you were expecting.
375 You need to configure your machine with a fully qualified domain name,
376 (i.e., a name with at least one "."), either in /etc/hostname
377 or wherever your system calls for specifying this.
379 If you cannot fix the configuration, you can set the Lisp variable
380 mail-host-address to the value you want.
384 *** Emacs says it has saved a file, but the file does not actually
387 This can happen on certain systems when you are using NFS, if the
388 remote disk is full. It is due to a bug in NFS (or certain NFS
389 implementations), and there is apparently nothing Emacs can do to
390 detect the problem. Emacs checks the failure codes of all the system
391 calls involved in writing a file, including 'close'; but in the case
392 where the problem occurs, none of those system calls fails.
394 ** PSGML conflicts with sgml-mode.
396 PSGML package uses the same names of some variables (like keymap)
397 as built-in sgml-mode.el because it was created as a replacement
398 of that package. The conflict will be shown if you load
399 sgml-mode.el before psgml.el. E.g. this could happen if you edit
400 HTML page and then start to work with SGML or XML file. html-mode
401 (from sgml-mode.el) is used for HTML file and loading of psgml.el
402 (for sgml-mode or xml-mode) will cause an error.
406 *** Lines are not updated or new lines are added in the buffer upon commit.
408 When committing files located higher in the hierarchy than the examined
409 directory, some versions of the CVS program return an ambiguous message
410 from which PCL-CVS cannot extract the full location of the committed
411 files. As a result, the corresponding lines in the PCL-CVS buffer are
412 not updated with the new revision of these files, and new lines are
413 added to the top-level directory.
415 This can happen with CVS versions 1.12.8 and 1.12.9. Upgrade to CVS
416 1.12.10 or newer to fix this problem.
418 ** Miscellaneous problems
420 *** Editing files with very long lines is slow.
422 For example, simply moving through a file that contains hundreds of
423 thousands of characters per line is slow, and consumes a lot of CPU.
424 This is a known limitation of Emacs with no solution at this time.
426 *** Emacs uses 100% of CPU time
428 This was a known problem with some old versions of the Semantic package.
429 The solution was to upgrade Semantic to version 2.0pre4 (distributed
430 with CEDET 1.0pre4) or later. Note that Emacs includes Semantic since
431 23.2, and this issue does not apply to the included version.
433 *** Self-documentation messages are garbled.
435 This means that the file 'etc/DOC' doesn't properly correspond
436 with the Emacs executable. Redumping Emacs and then installing the
437 corresponding pair of files should fix the problem.
439 *** Programs running under terminal emulator do not recognize 'emacs'
442 The cause of this is a shell startup file that sets the TERMCAP
443 environment variable. The terminal emulator uses that variable to
444 provide the information on the special terminal type that Emacs emulates.
446 Rewrite your shell startup file so that it does not change TERMCAP
447 in such a case. You could use the following conditional which sets
448 it only if it is undefined.
450 if ( ! ${?TERMCAP} ) setenv TERMCAP ~/my-termcap-file
452 Or you could set TERMCAP only when you set TERM--which should not
453 happen in a non-login shell.
455 *** In Shell mode, you get a ^M at the end of every line.
457 This happens to people who use tcsh, because it is trying to be too
458 smart. It sees that the Shell uses terminal type 'unknown' and turns
459 on the flag to output ^M at the end of each line. You can fix the
460 problem by adding this to your .cshrc file:
462 if ($?INSIDE_EMACS && $?tcsh)
464 stty -icrnl -onlcr -echo susp ^Z
467 *** Emacs startup on GNU/Linux systems (and possibly other systems) is slow.
469 This can happen if the system is misconfigured and Emacs can't get the
470 full qualified domain name, FQDN. You should have your FQDN in the
471 /etc/hosts file, something like this:
474 129.187.137.82 nuc04.t30.physik.tu-muenchen.de nuc04
476 The way to set this up may vary on non-GNU systems.
478 *** Visiting files in some auto-mounted directories causes Emacs to print
479 'Error reading dir-locals: (file-error "Read error" "is a directory" ...'
481 This can happen if the auto-mounter mistakenly reports that
482 .dir-locals.el exists and is a directory. There is nothing Emacs can
483 do about this, but you can avoid the issue by adding a suitable entry
484 to the variable 'locate-dominating-stop-dir-regexp'. For example, if
485 the problem relates to "/smb/.dir-locals.el", set that variable
486 to a new value where you replace "net\\|afs" with "net\\|afs\\|smb".
487 (The default value already matches common auto-mount prefixes.)
488 See http://lists.gnu.org/archive/html/help-gnu-emacs/2015-02/msg00461.html .
490 *** Attempting to visit remote files via ange-ftp fails.
492 If the error message is "ange-ftp-file-modtime: Specified time is not
493 representable", then this could happen when 'lukemftp' is used as the
494 ftp client. This was reported to happen on Debian GNU/Linux, kernel
495 version 2.4.3, with 'lukemftp' 1.5-5, but might happen on other
496 systems as well. To avoid this problem, switch to using the standard
497 ftp client. On a Debian system, type
499 update-alternatives --config ftp
501 and then choose /usr/bin/netkit-ftp.
503 *** Dired is very slow.
505 This could happen if invocation of the 'df' program takes a long
506 time. Possible reasons for this include:
508 - ClearCase mounted filesystems (VOBs) that sometimes make 'df'
509 response time extremely slow (dozens of seconds);
511 - slow automounters on some old versions of Unix;
513 - slow operation of some versions of 'df'.
515 To work around the problem, you could either (a) set the variable
516 'directory-free-space-program' to nil, and thus prevent Emacs from
517 invoking 'df'; (b) use 'df' from the GNU Coreutils package; or
518 (c) use CVS, which is Free Software, instead of ClearCase.
520 *** ps-print commands fail to find prologue files ps-prin*.ps.
522 This can happen if you use an old version of X-Symbol package: it
523 defines compatibility functions which trick ps-print into thinking it
524 runs in XEmacs, and look for the prologue files in a wrong directory.
526 The solution is to upgrade X-Symbol to a later version.
528 *** On systems with shared libraries you might encounter run-time errors
529 from the dynamic linker telling you that it is unable to find some
530 shared libraries, for instance those for Xaw3d or image support.
531 These errors mean Emacs has been linked with a library whose shared
532 library is not in the default search path of the dynamic linker.
534 Similar problems could prevent Emacs from building, since the build
535 process invokes Emacs several times.
537 On many systems, it is possible to set LD_LIBRARY_PATH in your
538 environment to specify additional directories where shared libraries
541 Other systems allow to set LD_RUN_PATH in a similar way, but before
542 Emacs is linked. With LD_RUN_PATH set, the linker will include a
543 specified run-time search path in the executable.
545 On some systems, Emacs can crash due to problems with dynamic
546 linking. Specifically, on SGI Irix 6.5, crashes were reported with
547 backtraces like this:
550 0 strcmp(0xf49239d, 0x4031184, 0x40302b4, 0x12, 0xf0000000, 0xf4923aa, 0x0, 0x492ddb2) ["/xlv22/ficus-jan23/work/irix/lib/libc/libc_n32_M3_ns/strings/strcmp.s":35, 0xfb7e480]
551 1 general_find_symbol(0xf49239d, 0x0, 0x0, 0x0, 0xf0000000, 0xf4923aa, 0x0, 0x492ddb2)
552 ["/comp2/mtibuild/v73/workarea/v7.3/rld/rld.c":2140, 0xfb65a98]
553 2 resolve_symbol(0xf49239d, 0x4031184, 0x0, 0xfbdd438, 0x0, 0xf4923aa, 0x0, 0x492ddb2)
554 ["/comp2/mtibuild/v73/workarea/v7.3/rld/rld.c":1947, 0xfb657e4]
555 3 lazy_text_resolve(0xd18, 0x1a3, 0x40302b4, 0x12, 0xf0000000, 0xf4923aa, 0x0, 0x492ddb2)
556 ["/comp2/mtibuild/v73/workarea/v7.3/rld/rld.c":997, 0xfb64d44]
557 4 _rld_text_resolve(0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0)
558 ["/comp2/mtibuild/v73/workarea/v7.3/rld/rld_bridge.s":175, 0xfb6032c]
560 ('rld' is the dynamic linker.) We don't know why this
561 happens, but setting the environment variable LD_BIND_NOW to 1 (which
562 forces the dynamic linker to bind all shared objects early on) seems
563 to work around the problem.
565 Please refer to the documentation of your dynamic linker for details.
567 *** When you run Ispell from Emacs, it reports a "misalignment" error.
569 This can happen if you compiled the Ispell program to use ASCII
570 characters only and then try to use it from Emacs with non-ASCII
571 characters, like Latin-1. The solution is to recompile Ispell with
572 support for 8-bit characters.
574 To see whether your Ispell program supports 8-bit characters, type
575 this at your shell's prompt:
579 and look in the output for the string "NO8BIT". If Ispell says
580 "!NO8BIT (8BIT)", your speller supports 8-bit characters; otherwise it
583 To rebuild Ispell with 8-bit character support, edit the local.h file
584 in the Ispell distribution and make sure it does _not_ define NO8BIT.
585 Then rebuild the speller.
587 Another possible cause for "misalignment" error messages is that the
588 version of Ispell installed on your machine is old. Upgrade.
590 Yet another possibility is that you are trying to spell-check a word
591 in a language that doesn't fit the dictionary you choose for use by
592 Ispell. (Ispell can only spell-check one language at a time, because
593 it uses a single dictionary.) Make sure that the text you are
594 spelling and the dictionary used by Ispell conform to each other.
596 If your spell-checking program is Aspell, it has been reported that if
597 you have a personal configuration file (normally ~/.aspell.conf), it
598 can cause this error. Remove that file, execute 'ispell-kill-ispell'
599 in Emacs, and then try spell-checking again.
601 *** Emacs eats all file descriptors when using kqueue file notifications.
602 See <http://debbugs.gnu.org/22814>.
604 When you have a large number of buffers running auto-revert-mode, and
605 Emacs is configured to use the kqueue file notification library, it
606 uses an own file descriptor for every watched file. On systems with a
607 small limit of file descriptors allowed per process, like OS X, you
608 could run out of file descriptors. You won't be able to open new files.
610 auto-revert-use-notify is set to nil in global-auto-revert-mode, therefore.
612 * Runtime problems related to font handling
614 ** Characters are displayed as empty boxes or with wrong font under X.
616 *** This can occur when two different versions of FontConfig are used.
617 For example, XFree86 4.3.0 has one version and Gnome usually comes
618 with a newer version. Emacs compiled with Gtk+ will then use the
619 newer version. In most cases the problem can be temporarily fixed by
620 stopping the application that has the error (it can be Emacs or any
621 other application), removing ~/.fonts.cache-1, and then starting the
622 application again. If removing ~/.fonts.cache-1 and restarting
623 doesn't help, the application with problem must be recompiled with the
624 same version of FontConfig as the rest of the system uses. For KDE,
625 it is sufficient to recompile Qt.
627 *** Some fonts have a missing glyph and no default character. This is
628 known to occur for character number 160 (no-break space) in some
629 fonts, such as Lucida but Emacs sets the display table for the unibyte
630 and Latin-1 version of this character to display a space.
632 *** Some of the fonts called for in your fontset may not exist on your
635 Each X font covers just a fraction of the characters that Emacs
636 supports. To display the whole range of Emacs characters requires
637 many different fonts, collected into a fontset. You can remedy the
638 problem by installing additional fonts.
640 The intlfonts distribution includes a full spectrum of fonts that can
641 display all the characters Emacs supports. The etl-unicode collection
642 of fonts (available from <URL:ftp://ftp.x.org/contrib/fonts/>) includes
643 fonts that can display many Unicode characters; they can also be used
644 by ps-print and ps-mule to print Unicode characters.
646 ** Under X, some characters appear improperly aligned in their lines.
648 You may have bad fonts.
650 ** Under X, an unexpected monospace font is used as the default font.
652 When compiled with XFT, Emacs tries to use a default font named
653 "monospace". This is a "virtual font", which the operating system
654 (Fontconfig) redirects to a suitable font such as DejaVu Sans Mono.
655 On some systems, there exists a font that is actually named Monospace,
656 which takes over the virtual font. This is considered an operating
659 http://lists.gnu.org/archive/html/emacs-devel/2008-10/msg00696.html
661 If you encounter this problem, set the default font to a specific font
662 in your .Xresources or initialization file. For instance, you can put
663 the following in your .Xresources:
665 Emacs.font: DejaVu Sans Mono 12
667 ** Certain fonts make each line take one pixel more than it should.
669 This is because these fonts contain characters a little taller than
670 the font's nominal height. Emacs needs to make sure that lines do not
673 ** Font Lock displays portions of the buffer in incorrect faces.
675 By far the most frequent cause of this is a parenthesis '(' or a brace
676 '{' in column zero. Font Lock assumes that such a paren is outside of
677 any comment or string. This is of course not true in general, but the
678 vast majority of well-formatted program source files don't have such
679 parens, and therefore this assumption is used to allow optimizations
680 in Font Lock's syntactical analysis. These optimizations avoid some
681 pathological cases where jit-lock, the Just-in-Time fontification
682 introduced with Emacs 21.1, could significantly slow down scrolling
683 through the buffer, especially scrolling backwards, and also jumping
684 to the end of a very large buffer.
686 Beginning with version 22.1, a parenthesis or a brace in column zero
687 is highlighted in bold-red face if it is inside a string or a comment,
688 to indicate that it could interfere with Font Lock (and also with
689 indentation) and should be moved or escaped with a backslash.
691 If you don't use large buffers, or have a very fast machine which
692 makes the delays insignificant, you can avoid the incorrect
693 fontification by setting the variable
694 'font-lock-beginning-of-syntax-function' to a nil value. (This must
695 be done _after_ turning on Font Lock.)
697 Another alternative is to avoid a paren in column zero. For example,
698 in a Lisp string you could precede the paren with a backslash.
700 ** Emacs pauses for several seconds when changing the default font.
702 This has been reported for fvwm 2.2.5 and the window manager of KDE
703 2.1. The reason for the pause is Xt waiting for a ConfigureNotify
704 event from the window manager, which the window manager doesn't send.
705 Xt stops waiting after a default timeout of usually 5 seconds.
707 A workaround for this is to add something like
709 emacs.waitForWM: false
711 to your X resources. Alternatively, add '(wait-for-wm . nil)' to a
712 frame's parameter list, like this:
714 (modify-frame-parameters nil '((wait-for-wm . nil)))
716 (this should go into your '.emacs' file).
718 ** Underlines appear at the wrong position.
720 This is caused by fonts having a wrong UNDERLINE_POSITION property.
721 Examples are the 7x13 font on XFree86 prior to version 4.1, or the jmk
722 neep font from the Debian xfonts-jmk package prior to version 3.0.17.
723 To circumvent this problem, set x-use-underline-position-properties
724 to nil in your '.emacs'.
726 To see what is the value of UNDERLINE_POSITION defined by the font,
727 type 'xlsfonts -lll FONT' and look at the font's UNDERLINE_POSITION property.
729 ** When using Exceed, fonts sometimes appear too tall.
731 When the display is set to an Exceed X-server and fonts are specified
732 (either explicitly with the -fn option or implicitly with X resources)
733 then the fonts may appear "too tall". The actual character sizes are
734 correct but there is too much vertical spacing between rows, which
735 gives the appearance of "double spacing".
737 To prevent this, turn off the Exceed's "automatic font substitution"
738 feature (in the font part of the configuration window).
740 ** Subscript/superscript text in TeX is hard to read.
742 If 'tex-fontify-script' is non-nil, tex-mode displays
743 subscript/superscript text in the faces subscript/superscript, which
744 are smaller than the normal font and lowered/raised. With some fonts,
745 nested superscripts (say) can be hard to read. Switching to a
746 different font, or changing your antialiasing setting (on an LCD
747 screen), can both make the problem disappear. Alternatively, customize
748 the following variables: tex-font-script-display (how much to
749 lower/raise); tex-suscript-height-ratio (how much smaller than
750 normal); tex-suscript-height-minimum (minimum height).
752 * Internationalization problems
754 ** M-{ does not work on a Spanish PC keyboard.
756 Many Spanish keyboards seem to ignore that combination. Emacs can't
757 do anything about it.
759 ** International characters aren't displayed under X.
763 XFree86 4 contains many fonts in iso10646-1 encoding which have
764 minimal character repertoires (whereas the encoding part of the font
765 name is meant to be a reasonable indication of the repertoire
766 according to the XLFD spec). Emacs may choose one of these to display
767 characters from the mule-unicode charsets and then typically won't be
768 able to find the glyphs to display many characters. (Check with C-u
769 C-x = .) To avoid this, you may need to use a fontset which sets the
770 font for the mule-unicode sets explicitly. E.g. to use GNU unifont,
771 include in the fontset spec:
773 mule-unicode-2500-33ff:-gnu-unifont-*-iso10646-1,\
774 mule-unicode-e000-ffff:-gnu-unifont-*-iso10646-1,\
775 mule-unicode-0100-24ff:-gnu-unifont-*-iso10646-1
777 ** The UTF-8/16/7 coding systems don't encode CJK (Far Eastern) characters.
779 Emacs directly supports the Unicode BMP whose code points are in the
780 ranges 0000-33ff and e000-ffff, and indirectly supports the parts of
781 CJK characters belonging to these legacy charsets:
783 GB2312, Big5, JISX0208, JISX0212, JISX0213-1, JISX0213-2, KSC5601
785 The latter support is done in Utf-Translate-Cjk mode (turned on by
786 default). Which Unicode CJK characters are decoded into which Emacs
787 charset is decided by the current language environment. For instance,
788 in Chinese-GB, most of them are decoded into chinese-gb2312.
790 If you read UTF-8 data with code points outside these ranges, the
791 characters appear in the buffer as raw bytes of the original UTF-8
792 (composed into a single quasi-character) and they will be written back
793 correctly as UTF-8, assuming you don't break the composed sequences.
794 If you read such characters from UTF-16 or UTF-7 data, they are
795 substituted with the Unicode 'replacement character', and you lose
798 ** Accented ISO-8859-1 characters are displayed as | or _.
800 Try other font set sizes (S-mouse-1). If the problem persists with
801 other sizes as well, your text is corrupted, probably through software
802 that is not 8-bit clean. If the problem goes away with another font
803 size, it's probably because some fonts pretend to be ISO-8859-1 fonts
804 when they are really ASCII fonts. In particular the schumacher-clean
805 fonts have this bug in some versions of X.
807 To see what glyphs are included in a font, use 'xfd', like this:
809 xfd -fn -schumacher-clean-medium-r-normal--12-120-75-75-c-60-iso8859-1
811 If this shows only ASCII glyphs, the font is indeed the source of the problem.
813 The solution is to remove the corresponding lines from the appropriate
814 'fonts.alias' file, then run 'mkfontdir' in that directory, and then run
817 ** The 'oc-unicode' package doesn't work with Emacs 21.
819 This package tries to define more private charsets than there are free
820 slots now. The current built-in Unicode support is actually more
821 flexible. (Use option 'utf-translate-cjk-mode' if you need CJK
822 support.) Files encoded as emacs-mule using oc-unicode aren't
823 generally read correctly by Emacs 21.
827 ** X keyboard problems
829 *** You "lose characters" after typing Compose Character key.
831 This is because the Compose Character key is defined as the keysym
832 Multi_key, and Emacs (seeing that) does the proper X
833 character-composition processing. If you don't want your Compose key
834 to do that, you can redefine it with xmodmap.
836 For example, here's one way to turn it into a Meta key:
838 xmodmap -e "keysym Multi_key = Meta_L"
840 If all users at your site of a particular keyboard prefer Meta to
841 Compose, you can make the remapping happen automatically by adding the
842 xmodmap command to the xdm setup script for that display.
844 *** Using X Window System, control-shift-leftbutton makes Emacs hang.
846 Use the shell command 'xset bc' to make the old X Menu package work.
848 *** C-SPC fails to work on Fedora GNU/Linux (or with fcitx input method).
850 Fedora Core 4 steals the C-SPC key by default for the 'iiimx' program
851 which is the input method for some languages. It blocks Emacs users
852 from using the C-SPC key for 'set-mark-command'.
854 One solutions is to remove the '<Ctrl>space' from the 'Iiimx' file
855 which can be found in the '/usr/lib/X11/app-defaults' directory.
856 However, that requires root access.
858 Another is to specify 'Emacs*useXIM: false' in your X resources.
860 Another is to build Emacs with the '--without-xim' configure option.
862 The same problem happens on any other system if you are using fcitx
863 (Chinese input method) which by default use C-SPC for toggling. If
864 you want to use fcitx with Emacs, you have two choices. Toggle fcitx
865 by another key (e.g. C-\) by modifying ~/.fcitx/config, or be
866 accustomed to use C-@ for 'set-mark-command'.
868 *** Link-time optimization with clang doesn't work on Fedora 20.
870 As of May 2014, Fedora 20 has broken LLVMgold.so plugin support in clang
871 (tested with clang-3.4-6.fc20) - 'clang --print-file-name=LLVMgold.so'
872 prints 'LLVMgold.so' instead of full path to plugin shared library, and
873 'clang -flto' is unable to find the plugin with the following error:
875 /bin/ld: error: /usr/bin/../lib/LLVMgold.so: could not load plugin library:
876 /usr/bin/../lib/LLVMgold.so: cannot open shared object file: No such file
879 The only way to avoid this is to build your own clang from source code
880 repositories, as described at http://clang.llvm.org/get_started.html.
882 *** M-SPC seems to be ignored as input.
884 See if your X server is set up to use this as a command
885 for character composition.
887 *** The S-C-t key combination doesn't get passed to Emacs on X.
889 This happens because some X configurations assign the Ctrl-Shift-t
890 combination the same meaning as the Multi_key. The offending
891 definition is in the file '...lib/X11/locale/iso8859-1/Compose'; there
892 might be other similar combinations which are grabbed by X for similar
895 We think that this can be countermanded with the 'xmodmap' utility, if
896 you want to be able to bind one of these key sequences within Emacs.
898 *** Under X, C-v and/or other keys don't work.
900 These may have been intercepted by your window manager.
901 See the WM's documentation for how to change this.
903 *** Clicking C-mouse-2 in the scroll bar doesn't split the window.
905 This currently doesn't work with scroll-bar widgets (and we don't know
906 a good way of implementing it with widgets). If Emacs is configured
907 --without-toolkit-scroll-bars, C-mouse-2 on the scroll bar does work.
909 *** Inability to send an Alt-modified key, when Emacs is communicating
910 directly with an X server.
912 If you have tried to bind an Alt-modified key as a command, and it
913 does not work to type the command, the first thing you should check is
914 whether the key is getting through to Emacs. To do this, type C-h c
915 followed by the Alt-modified key. C-h c should say what kind of event
916 it read. If it says it read an Alt-modified key, then make sure you
917 have made the key binding correctly.
919 If C-h c reports an event that doesn't have the Alt modifier, it may
920 be because your X server has no key for the Alt modifier. The X
921 server that comes from MIT does not set up the Alt modifier by default.
923 If your keyboard has keys named Alt, you can enable them as follows:
925 xmodmap -e 'add mod2 = Alt_L'
926 xmodmap -e 'add mod2 = Alt_R'
928 If the keyboard has just one key named Alt, then only one of those
929 commands is needed. The modifier 'mod2' is a reasonable choice if you
930 are using an unmodified MIT version of X. Otherwise, choose any
931 modifier bit not otherwise used.
933 If your keyboard does not have keys named Alt, you can use some other
934 keys. Use the keysym command in xmodmap to turn a function key (or
935 some other 'spare' key) into Alt_L or into Alt_R, and then use the
936 commands show above to make them modifier keys.
938 Note that if you have Alt keys but no Meta keys, Emacs translates Alt
939 into Meta. This is because of the great importance of Meta in Emacs.
941 ** Window-manager and toolkit-related problems
943 *** Emacs built with GTK+ toolkit produces corrupted display on HiDPI screen
945 This can happen if you set GDK_SCALE=2 in the environment or in your
946 '.xinitrc' file. (This setting is usually accompanied by
947 GDK_DPI_SCALE=0.5.) Emacs can not support these settings correctly,
948 as it doesn't use GTK+ exclusively. The result is that sometimes
949 widgets like the scroll bar are displayed incorrectly, and frames
950 could be displayed "cropped" to only part of the stuff that should be
953 The workaround is to explicitly disable these settings when invoking
954 Emacs, for example (from a Posix shell prompt):
956 $ GDK_SCALE=1 GDK_DPI_SCALE=1 emacs
958 *** Metacity: Resizing Emacs or ALT-Tab causes X to be unresponsive.
960 This happens sometimes when using Metacity. Resizing Emacs or ALT-Tab:bing
961 makes the system unresponsive to the mouse or the keyboard. Killing Emacs
962 or shifting out from X and back again usually cures it (i.e. Ctrl-Alt-F1
963 and then Alt-F7). A bug for it is here:
964 https://bugs.launchpad.net/ubuntu/+source/metacity/+bug/231034.
965 Note that a permanent fix seems to be to disable "assistive technologies".
967 *** Gnome: Emacs receives input directly from the keyboard, bypassing XIM.
969 This seems to happen when gnome-settings-daemon version 2.12 or later
970 is running. If gnome-settings-daemon is not running, Emacs receives
971 input through XIM without any problem. Furthermore, this seems only
972 to happen in *.UTF-8 locales; zh_CN.GB2312 and zh_CN.GBK locales, for
973 example, work fine. A bug report has been filed in the Gnome
974 bugzilla: http://bugzilla.gnome.org/show_bug.cgi?id=357032
976 *** Gnome: Emacs's xterm-mouse-mode doesn't work on the Gnome terminal.
978 A symptom of this bug is that double-clicks insert a control sequence
979 into the buffer. The reason this happens is an apparent
980 incompatibility of the Gnome terminal with Xterm, which also affects
981 other programs using the Xterm mouse interface. A problem report has
984 *** KDE: When running on KDE, colors or fonts are not as specified for Emacs,
987 For example, you could see background you set for Emacs only in the
988 empty portions of the Emacs display, while characters have some other
991 This happens because KDE's defaults apply its color and font
992 definitions even to applications that weren't compiled for KDE. The
993 solution is to uncheck the "Apply fonts and colors to non-KDE apps"
994 option in Preferences->Look&Feel->Style (KDE 2). In KDE 3, this option
995 is in the "Colors" section, rather than "Style".
997 Alternatively, if you do want the KDE defaults to apply to other
998 applications, but not to Emacs, you could modify the file 'Emacs.ad'
999 (should be in the '/usr/share/apps/kdisplay/app-defaults/' directory)
1000 so that it doesn't set the default background and foreground only for
1001 Emacs. For example, make sure the following resources are either not
1002 present or commented out:
1004 Emacs.default.attributeForeground
1005 Emacs.default.attributeBackground
1009 It is also reported that a bug in the gtk-engines-qt engine can cause this if
1010 Emacs is compiled with Gtk+.
1011 The bug is fixed in version 0.7 or newer of gtk-engines-qt.
1013 *** KDE: Emacs hangs on KDE when a large portion of text is killed.
1015 This is caused by a bug in the KDE applet 'klipper' which periodically
1016 requests the X clipboard contents from applications. Early versions
1017 of klipper don't implement the ICCCM protocol for large selections,
1018 which leads to Emacs being flooded with selection requests. After a
1019 while, Emacs may print a message:
1021 Timed out waiting for property-notify event
1023 A workaround is to not use 'klipper'. Upgrading 'klipper' to the one
1024 coming with KDE 3.3 or later also solves the problem.
1026 *** CDE: Frames may cover dialogs they created when using CDE.
1028 This can happen if you have "Allow Primary Windows On Top" enabled which
1029 seems to be the default in the Common Desktop Environment.
1030 To change, go in to "Desktop Controls" -> "Window Style Manager"
1031 and uncheck "Allow Primary Windows On Top".
1033 *** Xaw3d : When using Xaw3d scroll bars without arrows, the very first mouse
1034 click in a scroll bar might be ignored by the scroll bar widget. This
1035 is probably a bug in Xaw3d; when Xaw3d is compiled with arrows, the
1038 *** Xaw: There are known binary incompatibilities between Xaw, Xaw3d, neXtaw,
1039 XawM and the few other derivatives of Xaw. So when you compile with
1040 one of these, it may not work to dynamically link with another one.
1041 For example, strange problems, such as Emacs exiting when you type
1042 "C-x 1", were reported when Emacs compiled with Xaw3d and libXaw was
1043 used with neXtaw at run time.
1045 The solution is to rebuild Emacs with the toolkit version you actually
1046 want to use, or set LD_PRELOAD to preload the same toolkit version you
1049 *** Open Motif: Problems with file dialogs in Emacs built with Open Motif.
1051 When Emacs 21 is built with Open Motif 2.1, it can happen that the
1052 graphical file dialog boxes do not work properly. The "OK", "Filter"
1053 and "Cancel" buttons do not respond to mouse clicks. Dragging the
1054 file dialog window usually causes the buttons to work again.
1056 As a workaround, you can try building Emacs using Motif or LessTif instead.
1058 Another workaround is not to use the mouse to trigger file prompts,
1059 but to use the keyboard. This way, you will be prompted for a file in
1060 the minibuffer instead of a graphical file dialog.
1062 *** LessTif: Problems in Emacs built with LessTif.
1064 The problems seem to depend on the version of LessTif and the Motif
1065 emulation for which it is set up.
1067 Only the Motif 1.2 emulation seems to be stable enough in LessTif.
1068 LessTif 0.92-17's Motif 1.2 emulation seems to work okay on FreeBSD.
1069 On GNU/Linux systems, lesstif-0.92.6 configured with "./configure
1070 --enable-build-12 --enable-default-12" is reported to be the most
1071 successful. The binary GNU/Linux package
1072 lesstif-devel-0.92.0-1.i386.rpm was reported to have problems with
1075 On some systems, Emacs occasionally locks up, grabbing all mouse and
1076 keyboard events. We don't know what causes these problems; they are
1077 not reproducible by Emacs developers.
1079 *** Motif: The Motif version of Emacs paints the screen a solid color.
1081 This has been observed to result from the following X resource:
1083 Emacs*default.attributeFont: -*-courier-medium-r-*-*-*-140-*-*-*-*-iso8859-*
1085 That the resource has this effect indicates a bug in something, but we
1086 do not know what. If it is an Emacs bug, we hope someone can
1087 explain what the bug is so we can fix it. In the mean time, removing
1088 the resource prevents the problem.
1090 ** General X problems
1092 *** Redisplay using X is much slower than previous Emacs versions.
1094 We've noticed that certain X servers draw the text much slower when
1095 scroll bars are on the left. We don't know why this happens. If this
1096 happens to you, you can work around it by putting the scroll bars
1097 on the right (as they were in Emacs 19).
1099 Here's how to do this:
1101 (set-scroll-bar-mode 'right)
1103 If you're not sure whether (or how much) this problem affects you,
1104 try that and see how much difference it makes. To set things back
1107 (set-scroll-bar-mode 'left)
1109 *** Error messages about undefined colors on X.
1111 The messages might say something like this:
1113 Unable to load color "grey95"
1115 (typically, in the '*Messages*' buffer), or something like this:
1117 Error while displaying tooltip: (error Undefined color lightyellow)
1119 These problems could happen if some other X program has used up too
1120 many colors of the X palette, leaving Emacs with insufficient system
1121 resources to load all the colors it needs.
1123 A solution is to exit the offending X programs before starting Emacs.
1125 "undefined color" messages can also occur if the RgbPath entry in the
1126 X configuration file is incorrect, or the rgb.txt file is not where
1127 X expects to find it.
1129 *** Improving performance with slow X connections.
1131 There are several ways to improve this performance, any subset of which can
1132 be carried out at the same time:
1134 1) If you don't need X Input Methods (XIM) for entering text in some
1135 language you use, you can improve performance on WAN links by using
1136 the X resource useXIM to turn off use of XIM. This does not affect
1137 the use of Emacs's own input methods, which are part of the Leim
1140 2) If the connection is very slow, you might also want to consider
1141 switching off scroll bars, menu bar, and tool bar. Adding the
1142 following forms to your .emacs file will accomplish that, but only
1143 after the initial frame is displayed:
1145 (scroll-bar-mode -1)
1149 For still quicker startup, put these X resources in your
1150 .Xresources or .Xdefaults file:
1152 Emacs.verticalScrollBars: off
1156 3) Use ssh to forward the X connection, and enable compression on this
1157 forwarded X connection (ssh -XC remotehostname emacs ...).
1159 4) Use lbxproxy on the remote end of the connection. This is an interface
1160 to the low bandwidth X extension in most modern X servers, which
1161 improves performance dramatically, at the slight expense of correctness
1162 of the X protocol. lbxproxy achieves the performance gain by grouping
1163 several X requests in one TCP packet and sending them off together,
1164 instead of requiring a round-trip for each X request in a separate
1165 packet. The switches that seem to work best for emacs are:
1166 -noatomsfile -nowinattr -cheaterrors -cheatevents
1167 Note that the -nograbcmap option is known to cause problems.
1168 For more about lbxproxy, see:
1169 http://www.x.org/archive/X11R6.8.0/doc/lbxproxy.1.html
1171 5) If copying and killing is slow, try to disable the interaction with the
1172 native system's clipboard by adding these lines to your .emacs file:
1173 (setq interprogram-cut-function nil)
1174 (setq interprogram-paste-function nil)
1176 *** Emacs gives the error, Couldn't find per display information.
1178 This can result if the X server runs out of memory because Emacs uses
1179 a large number of fonts. On systems where this happens, C-h h is
1182 We do not know of a way to prevent the problem.
1184 *** Emacs does not notice when you release the mouse.
1186 There are reports that this happened with (some) Microsoft mice and
1187 that replacing the mouse made it stop.
1189 *** You can't select from submenus (in the X toolkit version).
1191 On certain systems, mouse-tracking and selection in top-level menus
1192 works properly with the X toolkit, but neither of them works when you
1193 bring up a submenu (such as Bookmarks or Compare or Apply Patch, in
1196 This works on most systems. There is speculation that the failure is
1197 due to bugs in old versions of X toolkit libraries, but no one really
1198 knows. If someone debugs this and finds the precise cause, perhaps a
1199 workaround can be found.
1201 *** An error message such as 'X protocol error: BadMatch (invalid
1202 parameter attributes) on protocol request 93'.
1204 This comes from having an invalid X resource, such as
1206 (which is invalid because it specifies a color name for something
1207 that isn't a color.)
1209 The fix is to correct your X resources.
1211 *** Slow startup on X11R6 with X windows.
1213 If Emacs takes two minutes to start up on X11R6, see if your X
1214 resources specify any Adobe fonts. That causes the type-1 font
1215 renderer to start up, even if the font you asked for is not a type-1
1218 One way to avoid this problem is to eliminate the type-1 fonts from
1219 your font path, like this:
1221 xset -fp /usr/X11R6/lib/X11/fonts/Type1/
1223 *** Pull-down menus appear in the wrong place, in the toolkit version of Emacs.
1225 An X resource of this form can cause the problem:
1227 Emacs*geometry: 80x55+0+0
1229 This resource is supposed to apply, and does apply, to the menus
1230 individually as well as to Emacs frames. If that is not what you
1231 want, rewrite the resource.
1233 To check thoroughly for such resource specifications, use 'xrdb
1234 -query' to see what resources the X server records, and also look at
1235 the user's ~/.Xdefaults and ~/.Xdefaults-* files.
1237 *** Emacs running under X Window System does not handle mouse clicks.
1238 *** 'emacs -geometry 80x20' finds a file named '80x20'.
1240 One cause of such problems is having (setq term-file-prefix nil) in
1241 your .emacs file. Another cause is a bad value of EMACSLOADPATH in
1244 *** X doesn't work if DISPLAY uses a hostname.
1246 People have reported kernel bugs in certain systems that cause Emacs
1247 not to work with X if DISPLAY is set using a host name. But
1248 the problem does not occur if DISPLAY is set to 'unix:0.0'. I think
1249 the bug has to do with SIGIO or FIONREAD.
1251 You may be able to compensate for the bug by doing (set-input-mode nil nil).
1252 However, that has the disadvantage of turning off interrupts, so that
1253 you are unable to quit out of a Lisp program by typing C-g.
1255 *** Prevent double pastes in X
1257 The problem: a region, such as a command, is pasted twice when you copy
1258 it with your mouse from GNU Emacs to an xterm or an RXVT shell in X.
1259 The solution: try the following in your X configuration file,
1260 /etc/X11/xorg.conf This should enable both PS/2 and USB mice for
1261 single copies. You do not need any other drivers or options.
1263 Section "InputDevice"
1264 Identifier "Generic Mouse"
1266 Option "Device" "/dev/input/mice"
1269 *** Emacs is slow to exit in X
1271 After you use e.g. C-x C-c to exit, it takes many seconds before the
1272 Emacs window disappears. If Emacs was started from a terminal, you
1275 Error saving to X clipboard manager.
1276 If the problem persists, set 'x-select-enable-clipboard-manager' to nil.
1278 As the message suggests, this problem occurs when Emacs thinks you
1279 have a clipboard manager program running, but has trouble contacting it.
1280 If you don't want to use a clipboard manager, you can set the
1281 suggested variable. Or you can make Emacs not wait so long by
1282 reducing the value of 'x-selection-timeout', either in .emacs or with
1285 Sometimes this problem is due to a bug in your clipboard manager.
1286 Updating to the latest version of the manager can help.
1287 For example, in the Xfce 4.8 desktop environment, the clipboard
1288 manager in versions of xfce4-settings-helper before 4.8.2 is buggy;
1289 https://bugzilla.xfce.org/show_bug.cgi?id=7588 .
1291 *** Warning messages when running in Ubuntu
1293 When you start Emacs you may see something like this:
1295 (emacs:2286): LIBDBUSMENU-GTK-CRITICAL **: watch_submenu: assertion
1296 'GTK_IS_MENU_SHELL(menu)' failed
1298 This happens if the Emacs binary has been renamed. The cause is the Ubuntu
1299 appmenu concept. It tries to track Emacs menus and show them in the top
1300 panel, instead of in each Emacs window. This is not properly implemented,
1301 so it fails for Emacs. The order of menus is wrong, and things like copy/paste
1302 that depend on what state Emacs is in are usually wrong (i.e. paste disabled
1303 even if you should be able to paste, and similar).
1305 You can get back menus on each frame by starting emacs like this:
1306 % env UBUNTU_MENUPROXY= emacs
1308 * Runtime problems on character terminals
1310 ** The meta key does not work on xterm.
1312 Typing M-x rings the terminal bell, and inserts a string like ";120~".
1313 For recent xterm versions (>= 216), Emacs uses xterm's modifyOtherKeys
1314 feature to generate strings for key combinations that are not
1315 otherwise usable. One circumstance in which this can cause problems
1316 is if you have specified the X resource
1318 xterm*VT100.Translations
1320 to contain translations that use the meta key. Then xterm will not
1321 use meta in modified function-keys, which confuses Emacs. To fix
1322 this, you can remove the X resource or put this in your init file:
1324 (xterm-remove-modify-other-keys)
1326 ** Emacs spontaneously displays "I-search: " at the bottom of the screen.
1328 This means that Control-S/Control-Q (XON/XOFF) "flow control" is being
1329 used. C-s/C-q flow control is bad for Emacs editors because it takes
1330 away C-s and C-q as user commands. Since editors do not output long
1331 streams of text without user commands, there is no need for a
1332 user-issuable "stop output" command in an editor; therefore, a
1333 properly designed flow control mechanism would transmit all possible
1334 input characters without interference. Designing such a mechanism is
1335 easy, for a person with at least half a brain.
1337 There are three possible reasons why flow control could be taking place:
1339 1) Terminal has not been told to disable flow control
1340 2) Insufficient padding for the terminal in use
1341 3) Some sort of terminal concentrator or line switch is responsible
1343 First of all, many terminals have a set-up mode which controls whether
1344 they generate XON/XOFF flow control characters. This must be set to
1345 "no XON/XOFF" in order for Emacs to work. (For example, on a VT220
1346 you may select "No XOFF" in the setup menu.) Sometimes there is an
1347 escape sequence that the computer can send to turn flow control off
1348 and on. If so, perhaps the termcap 'ti' string should turn flow
1349 control off, and the 'te' string should turn it on.
1351 Once the terminal has been told "no flow control", you may find it
1352 needs more padding. The amount of padding Emacs sends is controlled
1353 by the termcap entry for the terminal in use, and by the output baud
1354 rate as known by the kernel. The shell command 'stty' will print
1355 your output baud rate; 'stty' with suitable arguments will set it if
1356 it is wrong. Setting to a higher speed causes increased padding. If
1357 the results are wrong for the correct speed, there is probably a
1358 problem in the termcap entry. You must speak to a local Unix wizard
1359 to fix this. Perhaps you are just using the wrong terminal type.
1361 For terminals that lack a "no flow control" mode, sometimes just
1362 giving lots of padding will prevent actual generation of flow control
1363 codes. You might as well try it.
1365 If you are really unlucky, your terminal is connected to the computer
1366 through a concentrator which sends XON/XOFF flow control to the
1367 computer, or it insists on sending flow control itself no matter how
1368 much padding you give it. Unless you can figure out how to turn flow
1369 control off on this concentrator (again, refer to your local wizard),
1370 you are screwed! You should have the terminal or concentrator
1371 replaced with a properly designed one. In the mean time, some drastic
1372 measures can make Emacs semi-work.
1374 You can make Emacs ignore C-s and C-q and let the operating system
1375 handle them. To do this on a per-session basis, just type M-x
1376 enable-flow-control RET. You will see a message that C-\ and C-^ are
1377 now translated to C-s and C-q. (Use the same command M-x
1378 enable-flow-control to turn *off* this special mode. It toggles flow
1381 If C-\ and C-^ are inconvenient for you (for example, if one of them
1382 is the escape character of your terminal concentrator), you can choose
1383 other characters by setting the variables flow-control-c-s-replacement
1384 and flow-control-c-q-replacement. But choose carefully, since all
1385 other control characters are already used by emacs.
1387 IMPORTANT: if you type C-s by accident while flow control is enabled,
1388 Emacs output will freeze, and you will have to remember to type C-q in
1391 If you work in an environment where a majority of terminals of a
1392 certain type are flow control hobbled, you can use the function
1393 'enable-flow-control-on' to turn on this flow control avoidance scheme
1394 automatically. Here is an example:
1396 (enable-flow-control-on "vt200" "vt300" "vt101" "vt131")
1398 If this isn't quite correct (e.g. you have a mixture of flow-control hobbled
1399 and good vt200 terminals), you can still run enable-flow-control
1402 I have no intention of ever redesigning the Emacs command set for the
1403 assumption that terminals use C-s/C-q flow control. XON/XOFF flow
1404 control technique is a bad design, and terminals that need it are bad
1405 merchandise and should not be purchased. Now that X is becoming
1406 widespread, XON/XOFF seems to be on the way out. If you can get some
1407 use out of GNU Emacs on inferior terminals, more power to you, but I
1408 will not make Emacs worse for properly designed systems for the sake
1409 of inferior systems.
1411 ** Control-S and Control-Q commands are ignored completely.
1413 For some reason, your system is using brain-damaged C-s/C-q flow
1414 control despite Emacs's attempts to turn it off. Perhaps your
1415 terminal is connected to the computer through a concentrator
1416 that wants to use flow control.
1418 You should first try to tell the concentrator not to use flow control.
1419 If you succeed in this, try making the terminal work without
1420 flow control, as described in the preceding section.
1422 If that line of approach is not successful, map some other characters
1423 into C-s and C-q using keyboard-translate-table. The example above
1424 shows how to do this with C-^ and C-\.
1426 ** Screen is updated wrong, but only on one kind of terminal.
1428 This could mean that the termcap entry you are using for that
1429 terminal is wrong, or it could mean that Emacs has a bug handling
1430 the combination of features specified for that terminal.
1432 The first step in tracking this down is to record what characters
1433 Emacs is sending to the terminal. Execute the Lisp expression
1434 (open-termscript "./emacs-script") to make Emacs write all
1435 terminal output into the file ~/emacs-script as well; then do
1436 what makes the screen update wrong, and look at the file
1437 and decode the characters using the manual for the terminal.
1438 There are several possibilities:
1440 1) The characters sent are correct, according to the terminal manual.
1442 In this case, there is no obvious bug in Emacs, and most likely you
1443 need more padding, or possibly the terminal manual is wrong.
1445 2) The characters sent are incorrect, due to an obscure aspect
1446 of the terminal behavior not described in an obvious way by termcap.
1448 This case is hard. It will be necessary to think of a way for
1449 Emacs to distinguish between terminals with this kind of behavior
1450 and other terminals that behave subtly differently but are
1451 classified the same by termcap; or else find an algorithm for
1452 Emacs to use that avoids the difference. Such changes must be
1453 tested on many kinds of terminals.
1455 3) The termcap entry is wrong.
1457 See the file etc/TERMS for information on changes
1458 that are known to be needed in commonly used termcap entries
1459 for certain terminals.
1461 4) The characters sent are incorrect, and clearly cannot be
1462 right for any terminal with the termcap entry you were using.
1464 This is unambiguously an Emacs bug, and can probably be fixed
1465 in termcap.c, tparam.c, term.c, scroll.c, cm.c or dispnew.c.
1467 ** Control-S and Control-Q commands are ignored completely on a net connection.
1469 Some versions of rlogin (and possibly telnet) do not pass flow
1470 control characters to the remote system to which they connect.
1471 On such systems, emacs on the remote system cannot disable flow
1472 control on the local system. Sometimes 'rlogin -8' will avoid this problem.
1474 One way to cure this is to disable flow control on the local host
1475 (the one running rlogin, not the one running rlogind) using the
1476 stty command, before starting the rlogin process. On many systems,
1477 "stty start u stop u" will do this. On some systems, use
1478 "stty -ixon" instead.
1480 Some versions of tcsh will prevent even this from working. One way
1481 around this is to start another shell before starting rlogin, and
1482 issue the stty command to disable flow control from that shell.
1484 If none of these methods work, the best solution is to type
1485 M-x enable-flow-control at the beginning of your emacs session, or
1486 if you expect the problem to continue, add a line such as the
1487 following to your .emacs (on the host running rlogind):
1489 (enable-flow-control-on "vt200" "vt300" "vt101" "vt131")
1491 See the entry about spontaneous display of I-search (above) for more info.
1493 ** Output from Control-V is slow.
1495 On many bit-map terminals, scrolling operations are fairly slow.
1496 Often the termcap entry for the type of terminal in use fails
1497 to inform Emacs of this. The two lines at the bottom of the screen
1498 before a Control-V command are supposed to appear at the top after
1499 the Control-V command. If Emacs thinks scrolling the lines is fast,
1500 it will scroll them to the top of the screen.
1502 If scrolling is slow but Emacs thinks it is fast, the usual reason is
1503 that the termcap entry for the terminal you are using does not
1504 specify any padding time for the 'al' and 'dl' strings. Emacs
1505 concludes that these operations take only as much time as it takes to
1506 send the commands at whatever line speed you are using. You must
1507 fix the termcap entry to specify, for the 'al' and 'dl', as much
1508 time as the operations really take.
1510 Currently Emacs thinks in terms of serial lines which send characters
1511 at a fixed rate, so that any operation which takes time for the
1512 terminal to execute must also be padded. With bit-map terminals
1513 operated across networks, often the network provides some sort of
1514 flow control so that padding is never needed no matter how slow
1515 an operation is. You must still specify a padding time if you want
1516 Emacs to realize that the operation takes a long time. This will
1517 cause padding characters to be sent unnecessarily, but they do
1518 not really cost much. They will be transmitted while the scrolling
1519 is happening and then discarded quickly by the terminal.
1521 Most bit-map terminals provide commands for inserting or deleting
1522 multiple lines at once. Define the 'AL' and 'DL' strings in the
1523 termcap entry to say how to do these things, and you will have
1524 fast output without wasted padding characters. These strings should
1525 each contain a single %-spec saying how to send the number of lines
1526 to be scrolled. These %-specs are like those in the termcap
1529 You should also define the 'IC' and 'DC' strings if your terminal
1530 has a command to insert or delete multiple characters. These
1531 take the number of positions to insert or delete as an argument.
1533 A 'cs' string to set the scrolling region will reduce the amount
1534 of motion you see on the screen when part of the screen is scrolled.
1536 ** You type Control-H (Backspace) expecting to delete characters.
1538 Put 'stty dec' in your .login file and your problems will disappear
1541 The choice of Backspace for erasure was based on confusion, caused by
1542 the fact that backspacing causes erasure (later, when you type another
1543 character) on most display terminals. But it is a mistake. Deletion
1544 of text is not the same thing as backspacing followed by failure to
1545 overprint. I do not wish to propagate this confusion by conforming
1548 For this reason, I believe 'stty dec' is the right mode to use,
1549 and I have designed Emacs to go with that. If there were a thousand
1550 other control characters, I would define Control-h to delete as well;
1551 but there are not very many other control characters, and I think
1552 that providing the most mnemonic possible Help character is more
1553 important than adapting to people who don't use 'stty dec'.
1555 If you are obstinate about confusing buggy overprinting with deletion,
1556 you can redefine Backspace in your .emacs file:
1557 (global-set-key "\b" 'delete-backward-char)
1558 You can probably access help-command via f1.
1560 ** Colors are not available on a tty or in xterm.
1562 Emacs 21 supports colors on character terminals and terminal
1563 emulators, but this support relies on the terminfo or termcap database
1564 entry to specify that the display supports color. Emacs looks at the
1565 "Co" capability for the terminal to find out how many colors are
1566 supported; it should be non-zero to activate the color support within
1567 Emacs. (Most color terminals support 8 or 16 colors.) If your system
1568 uses terminfo, the name of the capability equivalent to "Co" is
1571 In addition to the "Co" capability, Emacs needs the "op" (for
1572 "original pair") capability, which tells how to switch the terminal
1573 back to the default foreground and background colors. Emacs will not
1574 use colors if this capability is not defined. If your terminal entry
1575 doesn't provide such a capability, try using the ANSI standard escape
1576 sequence \E[00m (that is, define a new termcap/terminfo entry and make
1577 it use your current terminal's entry plus \E[00m for the "op"
1580 Finally, the "NC" capability (terminfo name: "ncv") tells Emacs which
1581 attributes cannot be used with colors. Setting this capability
1582 incorrectly might have the effect of disabling colors; try setting
1583 this capability to '0' (zero) and see if that helps.
1585 Emacs uses the database entry for the terminal whose name is the value
1586 of the environment variable TERM. With 'xterm', a common terminal
1587 entry that supports color is 'xterm-color', so setting TERM's value to
1588 'xterm-color' might activate the color support on an xterm-compatible
1591 Beginning with version 22.1, Emacs supports the --color command-line
1592 option which may be used to force Emacs to use one of a few popular
1593 modes for getting colors on a tty. For example, --color=ansi8 sets up
1594 for using the ANSI-standard escape sequences that support 8 colors.
1596 Some modes do not use colors unless you turn on the Font-lock mode.
1597 Some people have long ago set their '~/.emacs' files to turn on
1598 Font-lock on X only, so they won't see colors on a tty. The
1599 recommended way of turning on Font-lock is by typing "M-x
1600 global-font-lock-mode RET" or by customizing the variable
1601 'global-font-lock-mode'.
1603 ** Unexpected characters inserted into the buffer when you start Emacs.
1604 See e.g. <URL:http://debbugs.gnu.org/11129>
1606 This can happen when you start Emacs in -nw mode in an Xterm.
1607 For example, in the *scratch* buffer, you might see something like:
1611 This is more likely to happen if you are using Emacs over a slow
1612 connection, and begin typing before Emacs is ready to respond.
1614 This occurs when Emacs tries to query the terminal to see what
1615 capabilities it supports, and gets confused by the answer.
1616 To avoid it, set xterm-extra-capabilities to a value other than
1617 'check' (the default). See that variable's documentation (in
1618 term/xterm.el) for more details.
1620 * Runtime problems specific to individual Unix variants
1624 *** GNU/Linux: Process output is corrupted.
1626 There is a bug in Linux kernel 2.6.10 PTYs that can cause emacs to
1627 read corrupted process output.
1629 *** GNU/Linux: Remote access to CVS with SSH causes file corruption.
1631 If you access a remote CVS repository via SSH, files may be corrupted
1632 due to bad interaction between CVS, SSH, and libc.
1634 To fix the problem, save the following script into a file, make it
1635 executable, and set CVS_RSH environment variable to the file name of
1639 exec 2> >(exec cat >&2 2>/dev/null)
1642 *** GNU/Linux: Truncated svn annotate output with SSH.
1643 http://debbugs.gnu.org/7791
1645 The symptoms are: you are accessing a svn repository over SSH.
1646 You use vc-annotate on a large (several thousand line) file, and the
1647 result is truncated around the 1000 line mark. It works fine with
1648 other access methods (e.g. http), or from outside Emacs.
1650 This may be a similar libc/SSH issue to the one mentioned above for CVS.
1651 A similar workaround seems to be effective: create a script with the
1652 same contents as the one used above for CVS_RSH, and set the SVN_SSH
1653 environment variable to point to it.
1655 *** GNU/Linux: After upgrading to a newer version of Emacs,
1656 the Meta key stops working.
1658 This was reported to happen on a GNU/Linux system distributed by
1659 Mandrake. The reason is that the previous version of Emacs was
1660 modified by Mandrake to make the Alt key act as the Meta key, on a
1661 keyboard where the Windows key is the one which produces the Meta
1662 modifier. A user who started using a newer version of Emacs, which
1663 was not hacked by Mandrake, expected the Alt key to continue to act as
1664 Meta, and was astonished when that didn't happen.
1666 The solution is to find out what key on your keyboard produces the Meta
1667 modifier, and use that key instead. Try all of the keys to the left
1668 and to the right of the space bar, together with the 'x' key, and see
1669 which combination produces "M-x" in the echo area. You can also use
1670 the 'xmodmap' utility to show all the keys which produce a Meta
1673 xmodmap -pk | grep -Ei "meta|alt"
1675 A more convenient way of finding out which keys produce a Meta modifier
1676 is to use the 'xkbprint' utility, if it's available on your system:
1678 xkbprint 0:0 /tmp/k.ps
1680 This produces a PostScript file '/tmp/k.ps' with a picture of your
1681 keyboard; printing that file on a PostScript printer will show what
1682 keys can serve as Meta.
1684 The 'xkeycaps' also shows a visual representation of the current
1685 keyboard settings. It also allows to modify them.
1687 *** GNU/Linux: slow startup on Linux-based GNU systems.
1689 People using systems based on the Linux kernel sometimes report that
1690 startup takes 10 to 15 seconds longer than 'usual'.
1692 This is because Emacs looks up the host name when it starts.
1693 Normally, this takes negligible time; the extra delay is due to
1694 improper system configuration. This problem can occur for both
1695 networked and non-networked machines.
1697 Here is how to fix the configuration. It requires being root.
1699 **** Networked Case.
1701 First, make sure the files '/etc/hosts' and '/etc/host.conf' both
1702 exist. The first line in the '/etc/hosts' file should look like this
1703 (replace HOSTNAME with your host name):
1707 Also make sure that the '/etc/host.conf' files contains the following
1713 Any changes, permanent and temporary, to the host name should be
1714 indicated in the '/etc/hosts' file, since it acts a limited local
1715 database of addresses and names (e.g., some SLIP connections
1716 dynamically allocate ip addresses).
1718 **** Non-Networked Case.
1720 The solution described in the networked case applies here as well.
1721 However, if you never intend to network your machine, you can use a
1722 simpler solution: create an empty '/etc/host.conf' file. The command
1723 'touch /etc/host.conf' suffices to create the file. The '/etc/hosts'
1724 file is not necessary with this approach.
1726 *** GNU/Linux: Emacs on a tty switches the cursor to large blinking block.
1728 This was reported to happen on some GNU/Linux systems which use
1729 ncurses version 5.0, but could be relevant for other versions as well.
1730 These versions of ncurses come with a 'linux' terminfo entry, where
1731 the "cvvis" capability (termcap "vs") is defined as "\E[?25h\E[?8c"
1732 (show cursor, change size). This escape sequence switches on a
1733 blinking hardware text-mode cursor whose size is a full character
1734 cell. This blinking cannot be stopped, since a hardware cursor
1737 A work-around is to redefine the "cvvis" capability so that it
1738 enables a *software* cursor. The software cursor works by inverting
1739 the colors of the character at point, so what you see is a block
1740 cursor that doesn't blink. For this to work, you need to redefine
1741 the "cnorm" capability as well, so that it operates on the software
1742 cursor instead of the hardware cursor.
1744 To this end, run "infocmp linux > linux-term", edit the file
1745 'linux-term' to make both the "cnorm" and "cvvis" capabilities send
1746 the sequence "\E[?25h\E[?17;0;64c", and then run "tic linux-term" to
1747 produce a modified terminfo entry.
1749 Alternatively, if you want a blinking underscore as your Emacs cursor,
1750 set the 'visible-cursor' variable to nil in your ~/.emacs:
1751 (setq visible-cursor nil)
1753 Still other way is to change the "cvvis" capability to send the
1754 "\E[?25h\E[?0c" command.
1758 *** FreeBSD: Getting a Meta key on the console.
1760 By default, neither Alt nor any other key acts as a Meta key on
1761 FreeBSD, but this can be changed using kbdcontrol(1). Dump the
1762 current keymap to a file with the command
1764 $ kbdcontrol -d >emacs.kbd
1766 Edit emacs.kbd, and give the key you want to be the Meta key the
1767 definition 'meta'. For instance, if your keyboard has a "Windows"
1768 key with scan code 105, change the line for scan code 105 in emacs.kbd
1771 105 meta meta meta meta meta meta meta meta O
1773 to make the Windows key the Meta key. Load the new keymap with
1775 $ kbdcontrol -l emacs.kbd
1779 *** HP/UX : Shell mode gives the message, "`tty`: Ambiguous".
1781 christos@theory.tn.cornell.edu says:
1783 The problem is that in your .cshrc you have something that tries to
1784 execute 'tty'. If you are not running the shell on a real tty then
1785 tty will print "not a tty". Csh expects one word in some places,
1786 but tty is giving it back 3.
1788 The solution is to add a pair of quotes around `tty` to make it a single
1791 if (`tty` == "/dev/console")
1793 should be changed to:
1795 if ("`tty`" == "/dev/console")
1797 Even better, move things that set up terminal sections out of .cshrc
1800 *** HP/UX: 'Pid xxx killed due to text modification or page I/O error'.
1802 On HP/UX, you can get that error when the Emacs executable is on an NFS
1803 file system. HP/UX responds this way if it tries to swap in a page and
1804 does not get a response from the server within a timeout whose default
1805 value is just ten seconds.
1807 If this happens to you, extend the timeout period.
1809 *** HP/UX: The right Alt key works wrong on German HP keyboards (and perhaps
1810 other non-English HP keyboards too).
1812 This is because HP-UX defines the modifiers wrong in X. Here is a
1813 shell script to fix the problem; be sure that it is run after VUE
1814 configures the X server.
1816 xmodmap 2> /dev/null - << EOF
1817 keysym Alt_L = Meta_L
1818 keysym Alt_R = Meta_R
1823 keysym Mode_switch = NoSymbol
1825 keysym Meta_R = Mode_switch
1826 add mod2 = Mode_switch
1829 *** HP/UX: Emacs does not recognize the AltGr key.
1831 To fix this, set up a file ~/.dt/sessions/sessionetc with executable
1832 rights, containing this text:
1834 --------------------------------
1835 xmodmap 2> /dev/null - << EOF
1836 keysym Alt_L = Meta_L
1837 keysym Alt_R = Meta_R
1842 keysym Mode_switch = NoSymbol
1844 keysym Meta_R = Mode_switch
1845 add mod2 = Mode_switch
1847 --------------------------------
1849 *** HP/UX 11.0: Emacs makes HP/UX 11.0 crash.
1851 This is a bug in HPUX; HPUX patch PHKL_16260 is said to fix it.
1855 *** AIX: Trouble using ptys.
1857 People often install the pty devices on AIX incorrectly.
1858 Use 'smit pty' to reinstall them properly.
1860 *** AIXterm: Your Delete key sends a Backspace to the terminal.
1862 The solution is to include in your .Xdefaults the lines:
1864 *aixterm.Translations: #override <Key>BackSpace: string(0x7f)
1865 aixterm*ttyModes: erase ^?
1867 This makes your Backspace key send DEL (ASCII 127).
1869 *** AIX: If linking fails because libXbsd isn't found, check if you
1870 are compiling with the system's 'cc' and CFLAGS containing '-O5'. If
1871 so, you have hit a compiler bug. Please make sure to re-configure
1872 Emacs so that it isn't compiled with '-O5'.
1874 *** AIX 4.3.x or 4.4: Compiling fails.
1876 This could happen if you use /bin/c89 as your compiler, instead of
1877 the default 'cc'. /bin/c89 treats certain warnings, such as benign
1878 redefinitions of macros, as errors, and fails the build. A solution
1879 is to use the default compiler 'cc'.
1881 *** AIX 4: Some programs fail when run in a Shell buffer
1882 with an error message like No terminfo entry for "unknown".
1884 On AIX, many terminal type definitions are not installed by default.
1885 'unknown' is one of them. Install the "Special Generic Terminal
1886 Definitions" to make them defined.
1890 We list bugs in current versions here. See also the section on legacy
1893 *** On Solaris, C-x doesn't get through to Emacs when you use the console.
1895 This is a Solaris feature (at least on Intel x86 cpus). Type C-r
1896 C-r C-t, to toggle whether C-x gets through to Emacs.
1898 *** Problem with remote X server on Suns.
1900 On a Sun, running Emacs on one machine with the X server on another
1901 may not work if you have used the unshared system libraries. This
1902 is because the unshared libraries fail to use YP for host name lookup.
1903 As a result, the host name you specify may not be recognized.
1905 *** Solaris 2.6: Emacs crashes with SIGBUS or SIGSEGV on Solaris after you delete a frame.
1907 We suspect that this is a bug in the X libraries provided by
1908 Sun. There is a report that one of these patches fixes the bug and
1909 makes the problem stop:
1911 105216-01 105393-01 105518-01 105621-01 105665-01 105615-02 105216-02
1912 105667-01 105401-08 105615-03 105621-02 105686-02 105736-01 105755-03
1913 106033-01 105379-01 105786-01 105181-04 105379-03 105786-04 105845-01
1914 105284-05 105669-02 105837-01 105837-02 105558-01 106125-02 105407-01
1916 Another person using a newer system (kernel patch level Generic_105181-06)
1917 suspects that the bug was fixed by one of these more recent patches:
1919 106040-07 SunOS 5.6: X Input & Output Method patch
1920 106222-01 OpenWindows 3.6: filemgr (ff.core) fixes
1921 105284-12 Motif 1.2.7: sparc Runtime library patch
1923 *** Solaris 7 or 8: Emacs reports a BadAtom error (from X)
1925 This happens when Emacs was built on some other version of Solaris.
1926 Rebuild it on Solaris 8.
1928 *** When using M-x dbx with the SparcWorks debugger, the 'up' and 'down'
1929 commands do not move the arrow in Emacs.
1931 You can fix this by adding the following line to '~/.dbxinit':
1933 dbxenv output_short_file_name off
1935 *** On Solaris, CTRL-t is ignored by Emacs when you use
1936 the fr.ISO-8859-15 locale (and maybe other related locales).
1938 You can fix this by editing the file:
1940 /usr/openwin/lib/locale/iso8859-15/Compose
1942 Near the bottom there is a line that reads:
1944 Ctrl<t> <quotedbl> <Y> : "\276" threequarters
1946 while it should read:
1948 Ctrl<T> <quotedbl> <Y> : "\276" threequarters
1950 Note the lower case <t>. Changing this line should make C-t work.
1952 *** On Solaris, Emacs fails to set menu-bar-update-hook on startup, with error
1953 "Error in menu-bar-update-hook: (error Point before start of properties)".
1954 This seems to be a GCC optimization bug that occurs for GCC 4.1.2 (-g
1955 and -g -O2) and GCC 4.2.3 (-g -O and -g -O2). You can fix this by
1956 compiling with GCC 4.2.3 or CC 5.7, with no optimizations.
1960 *** Irix: Trouble using ptys, or running out of ptys.
1962 The program mkpts (which may be in '/usr/adm' or '/usr/sbin') needs to
1963 be set-UID to root, or non-root programs like Emacs will not be able
1964 to allocate ptys reliably.
1966 * Runtime problems specific to MS-Windows
1968 ** Emacs on Windows 9X requires UNICOWS.DLL
1970 If that DLL is not available, Emacs will display an error dialog
1971 stating its absence, and refuse to run.
1973 This is because Emacs 24.4 and later uses functions whose non-stub
1974 implementation is only available in UNICOWS.DLL, which implements the
1975 Microsoft Layer for Unicode on Windows 9X, or "MSLU". This article on
1978 http://msdn.microsoft.com/en-us/goglobal/bb688166.aspx
1980 includes a short description of MSLU and a link where it can be
1983 ** Emacs refuses to start on Windows 9X because ctime64 function is missing
1985 This is a sign that Emacs was compiled with MinGW runtime version
1986 4.0.x or later. These versions of runtime call in their startup code
1987 the ctime64 function, which does not exist in MSVCRT.DLL, the C
1988 runtime shared library, distributed with Windows 9X.
1990 A workaround is to build Emacs with MinGW runtime 3.x (the latest
1993 ** addpm fails to run on Windows NT4, complaining about Shell32.dll
1995 This is likely to happen because Shell32.dll shipped with NT4 lacks
1996 the updates required by Emacs. Installing Internet Explorer 4 solves
1997 the problem. Note that it is NOT enough to install IE6, because doing
1998 so will not install the Shell32.dll update.
2000 ** A few seconds delay is seen at startup and for many file operations
2002 This happens when the Net Logon service is enabled. During Emacs
2003 startup, this service issues many DNS requests looking up for the
2004 Windows Domain Controller. When Emacs accesses files on networked
2005 drives, it automatically logs on the user into those drives, which
2006 again causes delays when Net Logon is running.
2008 The solution seems to be to disable Net Logon with this command typed
2009 at the Windows shell prompt:
2013 To start the service again, type "net start netlogon". (You can also
2014 stop and start the service from the Computer Management application,
2015 accessible by right-clicking "My Computer" or "Computer", selecting
2016 "Manage", then clicking on "Services".)
2018 ** Emacs crashes when exiting the Emacs session
2020 This was reported to happen when some optional DLLs, such as those
2021 used for displaying images or the GnuTLS library or zlib compression
2022 library, which are loaded on-demand, have a runtime dependency on the
2023 libgcc DLL, libgcc_s_dw2-1.dll. The reason seems to be a bug in
2024 libgcc which rears its ugly head whenever the libgcc DLL is loaded
2025 after Emacs has started.
2027 One solution for this problem is to find an alternative build of the
2028 same optional library that does not depend on the libgcc DLL.
2030 Another possibility is to rebuild Emacs with the -shared-libgcc
2031 switch, which will force Emacs to load libgcc_s_dw2-1.dll on startup,
2032 ahead of any optional DLLs loaded on-demand later in the session.
2034 ** File selection dialog opens in incorrect directories
2036 Invoking the file selection dialog on Windows 7 or later shows a
2037 directory that is different from what was passed to 'read-file-name'
2038 or 'x-file-dialog' via their arguments.
2040 This is due to a deliberate change in behavior of the file selection
2041 dialogs introduced in Windows 7. It is explicitly described in the
2042 MSDN documentation of the GetOpenFileName API used by Emacs to pop up
2043 the file selection dialog. For the details, see
2045 http://msdn.microsoft.com/en-us/library/windows/desktop/ms646839%28v=vs.85%29.aspx
2047 The dialog shows the last directory in which the user selected a file
2048 in a previous invocation of the dialog with the same initial
2051 You can reset this "memory" of that directory by invoking the file
2052 selection dialog with a different initial directory.
2054 ** PATH can contain unexpanded environment variables
2056 Old releases of TCC (version 9) and 4NT (up to version 8) do not correctly
2057 expand App Paths entries of type REG_EXPAND_SZ. When Emacs is run from TCC
2058 and such an entry exists for emacs.exe, exec-path will contain the
2059 unexpanded entry. This has been fixed in TCC 10. For more information,
2062 ** Setting w32-pass-rwindow-to-system and w32-pass-lwindow-to-system to nil
2063 does not prevent the Start menu from popping up when the left or right
2064 "Windows" key is pressed.
2066 This was reported to happen when XKeymacs is installed. At least with
2067 XKeymacs Version 3.47, deactivating XKeymacs when Emacs is active is
2068 not enough to avoid its messing with the keyboard input. Exiting
2069 XKeymacs completely is reported to solve the problem.
2071 ** Pasting from Windows clipboard into Emacs doesn't work.
2073 This was reported to be the result of an anti-virus software blocking
2074 the clipboard-related operations when a Web browser is open, for
2075 security reasons. The solution is to close the Web browser while
2076 working in Emacs, or to add emacs.exe to the list of applications that
2077 are allowed to use the clipboard when the Web browser is open.
2079 ** "Pinning" Emacs to the taskbar doesn't work on Windows 10
2081 "Doesn't work" here means that if you invoke Emacs by clicking on the
2082 pinned icon, a separate button appears on the taskbar, instead of the
2083 expected effect of the icon you clicked on being converted to that
2086 This is due to a bug in early versions of Windows 10, reportedly fixed
2087 in build 1511 of Windows 10 (a.k.a. "Windows 10 SP1"). If you cannot
2088 upgrade, read the work-around described below.
2090 First, be sure to edit the Properties of the pinned icon to invoke
2091 runemacs.exe, not emacs.exe. (The latter will cause an extra cmd
2092 window to appear when you invoke Emacs from the pinned icon.)
2094 But the real cause of the problem is the fact that the pinned icon
2095 (which is really a shortcut in a special directory) lacks a unique
2096 application-defined Application User Model ID (AppUserModelID) that
2097 identifies the current process to the taskbar. This identifier allows
2098 an application to group its associated processes and windows under a
2099 single taskbar button. Emacs on Windows specifies a unique
2100 AppUserModelID when it starts, but Windows 10, unlike previous
2101 versions of MS-Windows, does not propagate that ID to the pinned icon.
2103 To work around this, use some utility, such as 'win7appid', to set the
2104 AppUserModelID of the pinned icon to the string "Gnu.Emacs". The
2105 shortcut files corresponding to icons you pinned are stored by Windows
2106 in the following subdirectory of your user's directory (by default
2107 C:\Users\<UserName>\):
2109 AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\TaskBar
2111 Look for the file 'emacs.lnk' there.
2113 ** Windows 95 and networking.
2115 To support server sockets, Emacs loads ws2_32.dll. If this file is
2116 missing, all Emacs networking features are disabled.
2118 Old versions of Windows 95 may not have the required DLL. To use
2119 Emacs's networking features on Windows 95, you must install the
2120 "Windows Socket 2" update available from MicroSoft's support Web.
2122 ** Emacs exits with "X protocol error" when run with an X server for MS-Windows.
2124 A certain X server for Windows had a bug which caused this.
2125 Supposedly the newer 32-bit version of this server doesn't have the
2128 ** Emacs crashes when opening a file with a UNC path and rails-mode is loaded.
2130 Loading rails-mode seems to interfere with UNC path handling. This has been
2131 reported as a bug against both Emacs and rails-mode, so look for an updated
2132 rails-mode that avoids this crash, or avoid using UNC paths if using
2135 ** M-x term does not work on MS-Windows.
2137 TTY emulation on Windows is undocumented, and programs such as stty
2138 which are used on POSIX platforms to control tty emulation do not
2139 exist for native windows terminals.
2141 ** Using create-fontset-from-ascii-font or the --font startup parameter
2142 with a Chinese, Japanese or Korean font leads to display problems.
2143 Use a Latin-only font as your default font. If you want control over
2144 which font is used to display Chinese, Japanese or Korean character,
2145 use create-fontset-from-fontset-spec to define a fontset.
2147 ** Frames are not refreshed while dialogs or menus are displayed
2149 This means no redisplay while the File or Font dialog or a pop-up menu
2150 is displayed. This also means tooltips with help text for pop-up
2151 menus are not displayed at all (except in a TTY session, where the help
2152 text is shown in the echo area). This is because message handling
2153 under Windows is synchronous, so we cannot handle repaint (or any
2154 other) messages while waiting for a system function, which popped up
2155 the menu/dialog, to return the result of the dialog or pop-up menu
2158 ** Help text in tooltips does not work on old Windows versions
2160 Windows 95 and Windows NT up to version 4.0 do not support help text
2161 for menus. Help text is only available in later versions of Windows.
2163 ** Display problems with ClearType method of smoothing
2165 When "ClearType" method is selected as the "method to smooth edges of
2166 screen fonts" (in Display Properties, Appearance tab, under
2167 "Effects"), there are various problems related to display of
2168 characters: Bold fonts can be hard to read, small portions of some
2169 characters could appear chopped, etc. This happens because, under
2170 ClearType, characters are drawn outside their advertised bounding box.
2171 Emacs 21 disabled the use of ClearType, whereas Emacs 22 allows it and
2172 has some code to enlarge the width of the bounding box. Apparently,
2173 this display feature needs more changes to get it 100% right. A
2174 workaround is to disable ClearType.
2176 ** Cursor is displayed as a thin vertical bar and cannot be changed
2178 This is known to happen if the Windows Magnifier is turned on before
2179 the Emacs session starts. The Magnifier affects the cursor shape and
2180 prevents any changes to it by setting the 'cursor-type' variable or
2183 The solution is to log off and on again, and then start the Emacs
2184 session only after turning the Magnifier off.
2186 To turn the Windows Magnifier off, click "Start->All Programs", or
2187 "All Apps", depending on your Windows version, then select
2188 "Accessibility" and click "Magnifier". In the Magnifier Settings
2189 dialog that opens, click "Exit".
2191 ** Problems with mouse-tracking and focus management
2193 There are problems with display if mouse-tracking is enabled and the
2194 mouse is moved off a frame, over another frame then back over the first
2195 frame. A workaround is to click the left mouse button inside the frame
2196 after moving back into it.
2198 Some minor flickering still persists during mouse-tracking, although
2199 not as severely as in 21.1.
2201 An inactive cursor remains in an active window after the Windows
2202 Manager driven switch of the focus, until a key is pressed.
2204 ** Problems with Windows input methods
2206 Some of the Windows input methods cause the keyboard to send
2207 characters encoded in the appropriate coding system (e.g., ISO 8859-1
2208 for Latin-1 characters, ISO 8859-8 for Hebrew characters, etc.). To
2209 make these input methods work with Emacs on Windows 9X, you might need
2210 to set the keyboard coding system to the appropriate value after you
2211 activate the Windows input method. For example, if you activate the
2212 Hebrew input method, type this:
2214 C-x RET k hebrew-iso-8bit RET
2216 In addition, to use these Windows input methods, you might need to set
2217 your "Language for non-Unicode programs" (on Windows XP, this is on
2218 the Advanced tab of Regional Settings) to the language of the input
2221 To bind keys that produce non-ASCII characters with modifiers, you
2222 must specify raw byte codes. For instance, if you want to bind
2223 META-a-grave to a command, you need to specify this in your '~/.emacs':
2225 (global-set-key [?\M-\340] ...)
2227 The above example is for the Latin-1 environment where the byte code
2228 of the encoded a-grave is 340 octal. For other environments, use the
2229 encoding appropriate to that environment.
2231 ** Problems with the %b format specifier for format-time-string
2233 The %b specifier for format-time-string does not produce abbreviated
2234 month names with consistent widths for some locales on some versions
2235 of Windows. This is caused by a deficiency in the underlying system
2238 ** Non-US time zones.
2240 Many non-US time zones are implemented incorrectly. This is due to
2241 over-simplistic handling of daylight savings switchovers by the
2244 ** Files larger than 4GB report wrong size in a 32-bit Windows build
2246 Files larger than 4GB cause overflow in the size (represented as a
2247 32-bit integer) reported by 'file-attributes'. This affects Dired as
2248 well, since the Windows port uses a Lisp emulation of 'ls', which relies
2249 on 'file-attributes'.
2251 ** Playing sound doesn't support the :data method
2253 Sound playing is not supported with the ':data DATA' key-value pair.
2254 You _must_ use the ':file FILE' method.
2256 ** Typing Alt-Shift has strange effects on MS-Windows.
2258 This combination of keys is a command to change keyboard layout. If
2259 you proceed to type another non-modifier key before you let go of Alt
2260 and Shift, the Alt and Shift act as modifiers in the usual way. A
2261 more permanent work around is to change it to another key combination,
2262 or disable it in the "Regional and Language Options" applet of the
2263 Control Panel. (The exact sequence of mouse clicks in the "Regional
2264 and Language Options" applet needed to find the key combination that
2265 changes the keyboard layout depends on your Windows version; for XP,
2266 in the Languages tab, click "Details" and then "Key Settings".)
2268 ** Interrupting Cygwin port of Bash from Emacs doesn't work.
2270 Cygwin 1.x builds of the ported Bash cannot be interrupted from the
2271 MS-Windows version of Emacs. This is due to some change in the Bash
2272 port or in the Cygwin library which apparently make Bash ignore the
2273 keyboard interrupt event sent by Emacs to Bash. (Older Cygwin ports
2274 of Bash, up to b20.1, did receive SIGINT from Emacs.)
2276 ** Accessing remote files with ange-ftp hangs the MS-Windows version of Emacs.
2278 If the FTP client is the Cygwin port of GNU 'ftp', this appears to be
2279 due to some bug in the Cygwin DLL or some incompatibility between it
2280 and the implementation of asynchronous subprocesses in the Windows
2281 port of Emacs. Specifically, some parts of the FTP server responses
2282 are not flushed out, apparently due to buffering issues, which
2285 The solution is to downgrade to an older version of the Cygwin DLL
2286 (version 1.3.2 was reported to solve the problem), or use the stock
2287 Windows FTP client, usually found in the 'C:\WINDOWS' or 'C:\WINNT'
2288 directory. To force ange-ftp use the stock Windows client, set the
2289 variable 'ange-ftp-ftp-program-name' to the absolute file name of the
2290 client's executable. For example:
2292 (setq ange-ftp-ftp-program-name "c:/windows/ftp.exe")
2294 If you want to stick with the Cygwin FTP client, you can work around
2295 this problem by putting this in your '.emacs' file:
2297 (setq ange-ftp-ftp-program-args '("-i" "-n" "-g" "-v" "--prompt" "")
2299 ** lpr commands don't work on MS-Windows with some cheap printers.
2301 This problem may also strike other platforms, but the solution is
2302 likely to be a global one, and not Emacs specific.
2304 Many cheap inkjet, and even some cheap laser printers, do not
2305 print plain text anymore, they will only print through graphical
2306 printer drivers. A workaround on MS-Windows is to use Windows's basic
2307 built in editor to print (this is possibly the only useful purpose it
2310 (setq printer-name "") ; notepad takes the default
2311 (setq lpr-command "notepad") ; notepad
2312 (setq lpr-switches nil) ; not needed
2313 (setq lpr-printer-switch "/P") ; run notepad as batch printer
2315 ** Antivirus software interacts badly with the MS-Windows version of Emacs.
2317 The usual manifestation of these problems is that subprocesses don't
2318 work or even wedge the entire system. In particular, "M-x shell RET"
2319 was reported to fail to work. But other commands also sometimes don't
2320 work when an antivirus package is installed.
2322 The solution is to switch the antivirus software to a less aggressive
2323 mode (e.g., disable the "auto-protect" feature), or even uninstall
2324 or disable it entirely.
2326 ** Pressing the mouse button on MS-Windows does not give a mouse-2 event.
2328 This is usually a problem with the mouse driver. Because most Windows
2329 programs do not do anything useful with the middle mouse button, many
2330 mouse drivers allow you to define the wheel press to do something
2331 different. Some drivers do not even have the option to generate a
2332 middle button press. In such cases, setting the wheel press to
2333 "scroll" sometimes works if you press the button twice. Trying a
2334 generic mouse driver might help.
2336 ** Scrolling the mouse wheel on MS-Windows always scrolls the top window.
2338 This is another common problem with mouse drivers. Instead of
2339 generating scroll events, some mouse drivers try to fake scroll bar
2340 movement. But they are not intelligent enough to handle multiple
2341 scroll bars within a frame. Trying a generic mouse driver might help.
2343 ** Mail sent through Microsoft Exchange in some encodings appears to be
2344 mangled and is not seen correctly in Rmail or Gnus. We don't know
2345 exactly what happens, but it isn't an Emacs problem in cases we've
2348 ** On MS-Windows, you cannot use the right-hand ALT key and the left-hand
2349 CTRL key together to type a Control-Meta character.
2351 This is a consequence of a misfeature beyond Emacs's control.
2353 Under Windows, the AltGr key on international keyboards generates key
2354 events with the modifiers Right-Alt and Left-Ctrl. Since Emacs cannot
2355 distinguish AltGr from an explicit Right-Alt and Left-Ctrl
2356 combination, whenever it sees Right-Alt and Left-Ctrl it assumes that
2357 AltGr has been pressed. The variable 'w32-recognize-altgr' can be set
2358 to nil to tell Emacs that AltGr is really Ctrl and Alt.
2360 ** Under some X-servers running on MS-Windows, Emacs's display is incorrect.
2362 The symptoms are that Emacs does not completely erase blank areas of the
2363 screen during scrolling or some other screen operations (e.g., selective
2364 display or when killing a region). M-x recenter will cause the screen
2365 to be completely redisplayed and the "extra" characters will disappear.
2367 This is known to occur under Exceed 6, and possibly earlier versions
2368 as well; it is reportedly solved in version 6.2.0.16 and later. The
2369 problem lies in the X-server settings.
2371 There are reports that you can solve the problem with Exceed by
2372 running 'Xconfig' from within NT, choosing "X selection", then
2373 un-checking the boxes "auto-copy X selection" and "auto-paste to X
2376 If this does not work, please inform bug-gnu-emacs@gnu.org. Then
2377 please call support for your X-server and see if you can get a fix.
2378 If you do, please send it to bug-gnu-emacs@gnu.org so we can list it here.
2380 * Build-time problems
2384 *** 'configure' warns "accepted by the compiler, rejected by the preprocessor".
2386 This indicates a mismatch between the C compiler and preprocessor that
2387 configure is using. For example, on Solaris 10 trying to use
2388 CC=/opt/SUNWspro/bin/cc (the Sun Studio compiler) together with
2389 CPP=/usr/ccs/lib/cpp can result in errors of this form (you may also
2390 see the error '"/usr/include/sys/isa_defs.h", line 500: undefined control').
2392 The solution is to tell configure to use the correct C preprocessor
2393 for your C compiler (CPP="/opt/SUNWspro/bin/cc -E" in the above
2398 *** Building Emacs over NFS fails with "Text file busy".
2400 This was reported to happen when building Emacs on a GNU/Linux system
2401 (Red Hat Linux 6.2) using a build directory automounted from Solaris
2402 (SunOS 5.6) file server, but it might not be limited to that
2403 configuration alone. Presumably, the NFS server doesn't commit the
2404 files' data to disk quickly enough, and the Emacs executable file is
2405 left "busy" for several seconds after Emacs has finished dumping
2406 itself. This causes the subsequent commands which invoke the dumped
2407 Emacs executable to fail with the above message.
2409 In some of these cases, a time skew between the NFS server and the
2410 machine where Emacs is built is detected and reported by GNU Make
2411 (it says that some of the files have modification time in the future).
2412 This might be a symptom of NFS-related problems.
2414 If the NFS server runs on Solaris, apply the Solaris patch 105379-05
2415 (Sunos 5.6: /kernel/misc/nfssrv patch). If that doesn't work, or if
2416 you have a different version of the OS or the NFS server, you can
2417 force the NFS server to use 1KB blocks, which was reported to fix the
2418 problem albeit at a price of slowing down file I/O. You can force 1KB
2419 blocks by specifying the "-o rsize=1024,wsize=1024" options to the
2420 'mount' command, or by adding ",rsize=1024,wsize=1024" to the mount
2421 options in the appropriate system configuration file, such as
2424 Alternatively, when Make fails due to this problem, you could wait for
2425 a few seconds and then invoke Make again. In one particular case,
2426 waiting for 10 or more seconds between the two Make invocations seemed
2427 to work around the problem.
2429 Similar problems can happen if your machine NFS-mounts a directory
2430 onto itself. Suppose the Emacs sources live in '/usr/local/src' and
2431 you are working on the host called 'marvin'. Then an entry in the
2432 '/etc/fstab' file like the following is asking for trouble:
2434 marvin:/usr/local/src /usr/local/src ...options.omitted...
2436 The solution is to remove this line from '/etc/fstab'.
2438 *** Building a 32-bit executable on a 64-bit GNU/Linux architecture.
2440 First ensure that the necessary 32-bit system libraries and include
2441 files are installed. Then use:
2443 env CC="gcc -m32" ./configure --build=i386-linux-gnu --x-libraries=/usr/lib
2445 (using the location of the 32-bit X libraries on your system).
2447 *** Building Emacs for Cygwin can fail with GCC 3
2449 As of Emacs 22.1, there have been stability problems with Cygwin
2450 builds of Emacs using GCC 3. Cygwin users are advised to use GCC 4.
2452 *** Building Emacs 23.3 and later will fail under Cygwin 1.5.19
2454 This is a consequence of a change to src/dired.c on 2010-07-27. The
2455 issue is that Cygwin 1.5.19 did not have d_ino in 'struct dirent'.
2458 http://lists.gnu.org/archive/html/emacs-devel/2010-07/msg01266.html
2460 *** Building the native MS-Windows port fails due to unresolved externals
2462 The linker error messages look like this:
2464 oo-spd/i386/ctags.o:ctags.c:(.text+0x156e): undefined reference to `_imp__re_set_syntax'
2465 collect2: ld returned 1 exit status
2467 This happens because GCC finds an incompatible regex.h header
2468 somewhere on the include path, before the version of regex.h supplied
2469 with Emacs. One such incompatible version of regex.h is part of the
2470 GnuWin32 Regex package.
2472 The solution is to remove the incompatible regex.h from the include
2473 path, when compiling Emacs. Alternatively, re-run the configure.bat
2474 script with the "-isystem C:/GnuWin32/include" switch (adapt for your
2475 system's place where you keep the GnuWin32 include files) -- this will
2476 cause the compiler to search headers in the directories specified by
2477 the Emacs Makefile _before_ it looks in the GnuWin32 include
2480 *** Building the native MS-Windows port with Cygwin GCC can fail.
2482 Emacs may not build using some Cygwin builds of GCC, such as Cygwin
2483 version 1.1.8, using the default configure settings. It appears to be
2484 necessary to specify the -mwin32 flag when compiling, and define
2485 __MSVCRT__, like so:
2487 configure --with-gcc --cflags -mwin32 --cflags -D__MSVCRT__
2489 *** Building the MS-Windows port fails with a CreateProcess failure.
2491 Some versions of mingw32 make on some versions of Windows do not seem
2492 to detect the shell correctly. Try "make SHELL=cmd.exe", or if that
2493 fails, try running make from Cygwin bash instead.
2495 *** Building 'ctags' for MS-Windows with the MinGW port of GCC fails.
2497 This might happen due to a bug in the MinGW header assert.h, which
2498 defines the 'assert' macro with a trailing semi-colon. The following
2499 patch to assert.h should solve this:
2501 *** include/assert.h.orig Sun Nov 7 02:41:36 1999
2502 --- include/assert.h Mon Jan 29 11:49:10 2001
2506 * If not debugging, assert does nothing.
2508 ! #define assert(x) ((void)0);
2510 #else /* debugging enabled */
2514 * If not debugging, assert does nothing.
2516 ! #define assert(x) ((void)0)
2518 #else /* debugging enabled */
2521 *** Building the MS-Windows port with Visual Studio 2005 fails.
2523 Microsoft no longer ships the single threaded version of the C library
2524 with their compiler, and the multithreaded static library is missing
2525 some functions that Microsoft have deemed non-threadsafe. The
2526 dynamically linked C library has all the functions, but there is a
2527 conflict between the versions of malloc in the DLL and in Emacs, which
2528 is not resolvable due to the way Windows does dynamic linking.
2530 We recommend the use of the MinGW port of GCC for compiling Emacs, as
2531 not only does it not suffer these problems, but it is also Free
2532 software like Emacs.
2534 *** Building the MS-Windows port with Visual Studio fails compiling emacs.rc
2536 If the build fails with the following message then the problem
2537 described here most likely applies:
2539 ../nt/emacs.rc(1) : error RC2176 : old DIB in icons\emacs.ico; pass it
2542 The Emacs icon contains a high resolution PNG icon for Vista, which is
2543 not recognized by older versions of the resource compiler. There are
2544 several workarounds for this problem:
2545 1. Use Free MinGW tools to compile, which do not have this problem.
2546 2. Install the latest Windows SDK.
2547 3. Replace emacs.ico with an older or edited icon.
2549 *** Building the MS-Windows port complains about unknown escape sequences.
2551 Errors and warnings can look like this:
2553 w32.c:1959:27: error: \x used with no following hex digits
2554 w32.c:1959:27: warning: unknown escape sequence '\i'
2556 This happens when paths using backslashes are passed to the compiler or
2557 linker (via -I and possibly other compiler flags); when these paths are
2558 included in source code, the backslashes are interpreted as escape sequences.
2559 See http://lists.gnu.org/archive/html/emacs-devel/2010-07/msg00995.html
2561 The fix is to use forward slashes in all paths passed to the compiler.
2565 *** Building Emacs with a system compiler fails to link because of an
2566 undefined symbol such as __eprintf which does not appear in Emacs.
2568 This can happen if some of the libraries linked into Emacs were built
2569 with GCC, but Emacs itself is being linked with a compiler other than
2570 GCC. Object files compiled with GCC might need some helper functions
2571 from libgcc.a, the library which comes with GCC, but the system
2572 compiler does not instruct the linker to search libgcc.a during the
2575 A solution is to link with GCC, like this:
2579 Since the .o object files already exist, this will not recompile Emacs
2580 with GCC, but just restart by trying again to link temacs.
2582 *** Sun with acc: Link failure when using acc on a Sun.
2584 To use acc, you need additional options just before the libraries, such as
2586 /usr/lang/SC2.0.1/values-Xt.o -L/usr/lang/SC2.0.1/cg87 -L/usr/lang/SC2.0.1
2588 and you need to add -lansi just before -lc.
2590 The precise file names depend on the compiler version, so we
2591 cannot easily arrange to supply them.
2593 *** 'tparam' reported as a multiply-defined symbol when linking with ncurses.
2595 This problem results from an incompatible change in ncurses, in
2596 version 1.9.9e approximately. This version is unable to provide a
2597 definition of tparm without also defining tparam. This is also
2598 incompatible with Terminfo; as a result, the Emacs Terminfo support
2599 does not work with this version of ncurses.
2601 The fix is to install a newer version of ncurses, such as version 4.2.
2605 Bootstrapping (compiling the .el files) is normally only necessary
2606 with development builds, since the .elc files are pre-compiled in releases.
2608 *** "No rule to make target" with Ubuntu 8.04 make 3.81-3build1
2610 Compiling the lisp files fails at random places, complaining:
2611 "No rule to make target '/path/to/some/lisp.elc'".
2612 The causes of this problem are not understood. Using GNU make 3.81 compiled
2613 from source, rather than the Ubuntu version, worked.
2614 See <URL:http://debbugs.gnu.org/327>, <URL:http://debbugs.gnu.org/821>.
2618 *** Segfault during 'make'
2620 If Emacs segfaults when 'make' executes one of these commands:
2622 LC_ALL=C ./temacs -batch -l loadup bootstrap
2623 LC_ALL=C ./temacs -batch -l loadup dump
2625 the problem may be due to inadequate workarounds for address space
2626 layout randomization (ASLR), an operating system feature that
2627 randomizes the virtual address space of a process. ASLR is commonly
2628 enabled in Linux and NetBSD kernels, and is intended to deter exploits
2629 of pointer-related bugs in applications. If ASLR is enabled, the
2632 cat /proc/sys/kernel/randomize_va_space # GNU/Linux
2633 sysctl security.pax.aslr.global # NetBSD
2635 outputs a nonzero value.
2637 These segfaults should not occur on most modern systems, because the
2638 Emacs build procedure uses the command 'setfattr' or 'paxctl' to mark
2639 the Emacs executable as requiring non-randomized address space, and
2640 Emacs uses the 'personality' system call to disable address space
2641 randomization when dumping. However, older kernels may not support
2642 'setfattr', 'paxctl', or 'personality', and newer Linux kernels have a
2643 secure computing mode (seccomp) that can be configured to disable the
2646 It may be possible to work around the 'personality' problem in a newer
2647 Linux kernel by configuring seccomp to allow the 'personality' call.
2648 For example, if you are building Emacs under Docker, you can run the
2649 Docker container with a security profile that allows 'personality' by
2650 using Docker's --security-opt option with an appropriate profile; see
2651 <https://docs.docker.com/engine/security/seccomp/>.
2653 To work around the ASLR problem in either an older or a newer kernel,
2654 you can temporarily disable the feature while building Emacs. On
2655 GNU/Linux you can do so using the following command (as root).
2657 echo 0 > /proc/sys/kernel/randomize_va_space
2659 You can re-enable the feature when you are done, by echoing the
2660 original value back to the file. NetBSD uses a different command,
2661 e.g., 'sysctl -w security.pax.aslr.global=0'.
2663 Alternatively, you can try using the 'setarch' command when building
2664 temacs like this, where -R disables address space randomization:
2666 setarch $(uname -m) -R make
2668 ASLR is not the only problem that can break Emacs dumping. Another
2669 issue is that in Red Hat Linux kernels, Exec-shield is enabled by
2670 default, and this creates a different memory layout. Emacs should
2671 handle this at build time, but if this fails the following
2672 instructions may be useful. Exec-shield is enabled on your system if
2674 cat /proc/sys/kernel/exec-shield
2676 prints a nonzero value. You can temporarily disable it as follows:
2678 echo 0 > /proc/sys/kernel/exec-shield
2680 As with randomize_va_space, you can re-enable Exec-shield when you are
2681 done, by echoing the original value back to the file.
2683 *** temacs prints "Pure Lisp storage exhausted".
2685 This means that the Lisp code loaded from the .elc and .el files during
2686 'temacs --batch --load loadup dump' took up more space than was allocated.
2688 This could be caused by
2689 1) adding code to the preloaded Lisp files
2690 2) adding more preloaded files in loadup.el
2691 3) having a site-init.el or site-load.el which loads files.
2692 Note that ANY site-init.el or site-load.el is nonstandard;
2693 if you have received Emacs from some other site and it contains a
2694 site-init.el or site-load.el file, consider deleting that file.
2695 4) getting the wrong .el or .elc files
2696 (not from the directory you expected).
2697 5) deleting some .elc files that are supposed to exist.
2698 This would cause the source files (.el files) to be
2699 loaded instead. They take up more room, so you lose.
2700 6) a bug in the Emacs distribution which underestimates the space required.
2702 If the need for more space is legitimate, change the definition
2703 of PURESIZE in puresize.h.
2705 But in some of the cases listed above, this problem is a consequence
2706 of something else that is wrong. Be sure to check and fix the real problem.
2708 *** OpenBSD 4.0 macppc: Segfault during dumping.
2710 The build aborts with signal 11 when the command './temacs --batch
2711 --load loadup bootstrap' tries to load files.el. A workaround seems
2712 to be to reduce the level of compiler optimization used during the
2713 build (from -O2 to -O1). It is possible this is an OpenBSD
2714 GCC problem specific to the macppc architecture, possibly only
2715 occurring with older versions of GCC (e.g. 3.3.5).
2717 *** openSUSE 10.3: Segfault in bcopy during dumping.
2719 This is due to a bug in the bcopy implementation in openSUSE 10.3.
2720 It is/will be fixed in an openSUSE update.
2724 *** Emacs binary is not in executable format, and cannot be run.
2726 This was reported to happen when Emacs is built in a directory mounted
2727 via NFS, for some combinations of NFS client and NFS server.
2728 Usually, the file 'emacs' produced in these cases is full of
2729 binary null characters, and the 'file' utility says:
2731 emacs: ASCII text, with no line terminators
2733 We don't know what exactly causes this failure. A work-around is to
2734 build Emacs in a directory on a local disk.
2736 *** The dumped Emacs crashes when run, trying to write pure data.
2738 On a system where getpagesize is not a system call, it is defined
2739 as a macro. If the definition (in both unex*.c and malloc.c) is wrong,
2740 it can cause problems like this. You might be able to find the correct
2741 value in the man page for a.out(5).
2743 * Problems on legacy systems
2745 This section covers bugs reported on very old hardware or software.
2746 If you are using hardware and an operating system shipped after 2000,
2747 it is unlikely you will see any of these.
2751 **** Strange results from format %d in a few cases, on a Sun.
2753 Sun compiler version SC3.0 has been found to miscompile part of editfns.c.
2754 The workaround is to compile with some other compiler such as GCC.
2756 **** On Solaris, Emacs dumps core if lisp-complete-symbol is called.
2758 If you compile Emacs with the -fast or -xO4 option with version 3.0.2
2759 of the Sun C compiler, Emacs dumps core when lisp-complete-symbol is
2760 called. The problem does not happen if you compile with GCC.
2762 **** On Solaris, Emacs crashes if you use (display-time).
2764 This can happen if you configure Emacs without specifying the precise
2765 version of Solaris that you are using.
2767 **** Solaris 2.x: GCC complains "64 bit integer types not supported".
2769 This suggests that GCC is not installed correctly. Most likely you
2770 are using GCC 2.7.2.3 (or earlier) on Solaris 2.6 (or later); this
2771 does not work without patching. To run GCC 2.7.2.3 on Solaris 2.6 or
2772 later, you must patch fixinc.svr4 and reinstall GCC from scratch as
2773 described in the Solaris FAQ
2774 <http://www.wins.uva.nl/pub/solaris/solaris2.html>. A better fix is
2775 to upgrade to GCC 2.8.1 or later.
2777 **** Solaris 2.7: Building Emacs with WorkShop Compilers 5.0 98/12/15
2778 C 5.0 failed, apparently with non-default CFLAGS, most probably due to
2779 compiler bugs. Using Sun Solaris 2.7 Sun WorkShop 6 update 1 C
2780 release was reported to work without problems. It worked OK on
2781 another system with Solaris 8 using apparently the same 5.0 compiler
2782 and the default CFLAGS.
2784 **** Solaris 2.x: Emacs dumps core when built with Motif.
2786 The Solaris Motif libraries are buggy, at least up through Solaris 2.5.1.
2787 Install the current Motif runtime library patch appropriate for your host.
2788 (Make sure the patch is current; some older patch versions still have the bug.)
2789 You should install the other patches recommended by Sun for your host, too.
2790 You can obtain Sun patches from ftp://sunsolve.sun.com/pub/patches/;
2791 look for files with names ending in '.PatchReport' to see which patches
2792 are currently recommended for your host.
2794 On Solaris 2.6, Emacs is said to work with Motif when Solaris patch
2795 105284-12 is installed, but fail when 105284-15 is installed.
2796 105284-18 might fix it again.
2798 **** Solaris 2.6 and 7: the Compose key does not work.
2800 This is a bug in Motif in Solaris. Supposedly it has been fixed for
2801 the next major release of Solaris. However, if someone with Sun
2802 support complains to Sun about the bug, they may release a patch.
2803 If you do this, mention Sun bug #4188711.
2805 One workaround is to use a locale that allows non-ASCII characters.
2806 For example, before invoking emacs, set the LC_ALL environment
2807 variable to "en_US" (American English). The directory /usr/lib/locale
2808 lists the supported locales; any locale other than "C" or "POSIX"
2811 pen@lysator.liu.se says (Feb 1998) that the Compose key does work
2812 if you link with the MIT X11 libraries instead of the Solaris X11 libraries.
2814 ** MS-Windows 95, 98, ME, and NT
2816 *** MS-Windows NT/95: Problems running Perl under Emacs
2818 'perl -de 0' just hangs when executed in an Emacs subshell.
2819 The fault lies with Perl (indirectly with Windows NT/95).
2821 The problem is that the Perl debugger explicitly opens a connection to
2822 "CON", which is the DOS/NT equivalent of "/dev/tty", for interacting
2825 On Unix, this is okay, because Emacs (or the shell?) creates a
2826 pseudo-tty so that /dev/tty is really the pipe Emacs is using to
2827 communicate with the subprocess.
2829 On NT, this fails because CON always refers to the handle for the
2830 relevant console (approximately equivalent to a tty), and cannot be
2831 redirected to refer to the pipe Emacs assigned to the subprocess as
2834 A workaround is to modify perldb.pl to use STDIN/STDOUT instead of CON.
2838 *** PERL/LIB/PERLDB.PL.orig Wed May 26 08:24:18 1993
2839 --- PERL/LIB/PERLDB.PL Mon Jul 01 15:28:16 1996
2846 $rcfile="perldb.ini";
2854 $rcfile="perldb.ini";
2859 *** perl/5.001/lib/perl5db.pl.orig Sun Jun 04 21:13:40 1995
2860 --- perl/5.001/lib/perl5db.pl Mon Jul 01 17:00:08 1996
2867 $rcfile="perldb.ini";
2875 $rcfile="perldb.ini";
2879 *** MS-Windows 95: Alt-f6 does not get through to Emacs.
2881 This character seems to be trapped by the kernel in Windows 95.
2882 You can enter M-f6 by typing ESC f6.
2884 *** MS-Windows 95/98/ME: subprocesses do not terminate properly.
2886 This is a limitation of the Operating System, and can cause problems
2887 when shutting down Windows. Ensure that all subprocesses are exited
2888 cleanly before exiting Emacs. For more details, see the Emacs on MS
2889 Windows FAQ (info manual "efaq-w32").
2891 *** MS-Windows 95/98/ME: crashes when Emacs invokes non-existent programs.
2893 When a program you are trying to run is not found on the PATH,
2894 Windows might respond by crashing or locking up your system. In
2895 particular, this has been reported when trying to compile a Java
2896 program in JDEE when javac.exe is installed, but not on the system PATH.
2900 *** When compiling with DJGPP on MS-Windows NT or later, "config msdos" fails.
2902 If the error message is "VDM has been already loaded", this is because
2903 Windows has a program called 'redir.exe' that is incompatible with a
2904 program by the same name supplied with DJGPP, which is used by
2905 config.bat. To resolve this, move the DJGPP's 'bin' subdirectory to
2906 the front of your PATH environment variable.
2908 *** When Emacs compiled with DJGPP runs on Windows 2000 and later, it cannot
2909 find your HOME directory.
2911 This was reported to happen when you click on "Save for future
2912 sessions" button in a Customize buffer. You might see an error
2913 message like this one:
2915 basic-save-buffer-2: c:/FOO/BAR/~dosuser/: no such directory
2917 (The telltale sign is the "~USER" part at the end of the directory
2918 Emacs complains about, where USER is your username or the literal
2919 string "dosuser", which is the default username set up by the DJGPP
2920 startup file DJGPP.ENV.)
2922 This happens when the functions 'user-login-name' and
2923 'user-real-login-name' return different strings for your username as
2924 Emacs sees it. To correct this, make sure both USER and USERNAME
2925 environment variables are set to the same value. Windows 2000 and
2926 later sets USERNAME, so if you want to keep that, make sure USER is
2927 set to the same value. If you don't want to set USER globally, you
2928 can do it in the [emacs] section of your DJGPP.ENV file.
2930 *** When Emacs compiled with DJGPP runs on Vista, it runs out of memory.
2932 If Emacs running on Vista displays "!MEM FULL!" in the mode line, you
2933 are hitting the memory allocation bugs in the Vista DPMI server. See
2934 msdos/INSTALL for how to work around these bugs (search for "Vista").
2936 *** When compiling with DJGPP on MS-Windows 95, Make fails for some targets
2939 This can happen if long file name support (the setting of environment
2940 variable LFN) when Emacs distribution was unpacked and during
2941 compilation are not the same. See msdos/INSTALL for the explanation
2942 of how to avoid this problem.
2944 *** Emacs compiled with DJGPP complains at startup:
2946 "Wrong type of argument: internal-facep, msdos-menu-active-face"
2948 This can happen if you define an environment variable 'TERM'. Emacs
2949 on MSDOS uses an internal terminal emulator which is disabled if the
2950 value of 'TERM' is anything but the string "internal". Emacs then
2951 works as if its terminal were a dumb glass teletype that doesn't
2952 support faces. To work around this, arrange for 'TERM' to be
2953 undefined when Emacs runs. The best way to do that is to add an
2954 [emacs] section to the DJGPP.ENV file which defines an empty value for
2955 'TERM'; this way, only Emacs gets the empty value, while the rest of
2956 your system works as before.
2958 *** MS-DOS: Emacs crashes at startup.
2960 Some users report that Emacs 19.29 requires dpmi memory management,
2961 and crashes on startup if the system does not have it. We don't
2962 know why this happens--perhaps these machines don't have enough real
2963 memory, or perhaps something is wrong in Emacs or the compiler.
2964 However, arranging to use dpmi support is a workaround.
2966 You can find out if you have a dpmi host by running go32 without
2967 arguments; it will tell you if it uses dpmi memory. For more
2968 information about dpmi memory, consult the djgpp FAQ. (djgpp
2969 is the GNU C compiler as packaged for MSDOS.)
2971 Compiling Emacs under MSDOS is extremely sensitive for proper memory
2972 configuration. If you experience problems during compilation, consider
2973 removing some or all memory resident programs (notably disk caches)
2974 and make sure that your memory managers are properly configured. See
2975 the djgpp faq for configuration hints.
2977 *** Emacs compiled with DJGPP for MS-DOS/MS-Windows cannot access files
2978 in the directory with the special name 'dev' under the root of any
2979 drive, e.g. 'c:/dev'.
2981 This is an unfortunate side-effect of the support for Unix-style
2982 device names such as /dev/null in the DJGPP runtime library. A
2983 work-around is to rename the problem directory to another name.
2985 *** MS-DOS: Emacs compiled for MSDOS cannot find some Lisp files, or other
2986 run-time support files, when long filename support is enabled.
2988 Usually, this problem will manifest itself when Emacs exits
2989 immediately after flashing the startup screen, because it cannot find
2990 the Lisp files it needs to load at startup. Redirect Emacs stdout
2991 and stderr to a file to see the error message printed by Emacs.
2993 Another manifestation of this problem is that Emacs is unable to load
2994 the support for editing program sources in languages such as C and Lisp.
2996 This can happen if the Emacs distribution was unzipped without LFN
2997 support, thus causing long filenames to be truncated to the first 6
2998 characters and a numeric tail that Windows 95 normally attaches to it.
2999 You should unzip the files again with a utility that supports long
3000 filenames (such as djtar from DJGPP or InfoZip's UnZip program
3001 compiled with DJGPP v2). The file msdos/INSTALL explains this issue
3004 Another possible reason for such failures is that Emacs compiled for
3005 MSDOS is used on Windows NT, where long file names are not supported
3006 by this version of Emacs, but the distribution was unpacked by an
3007 unzip program that preserved the long file names instead of truncating
3008 them to DOS 8+3 limits. To be useful on NT, the MSDOS port of Emacs
3009 must be unzipped by a DOS utility, so that long file names are
3012 ** Archaic window managers and toolkits
3014 *** Open Look: Under Open Look, the Emacs window disappears when you type M-q.
3016 Some versions of the Open Look window manager interpret M-q as a quit
3017 command for whatever window you are typing at. If you want to use
3018 Emacs with that window manager, you should try to configure the window
3019 manager to use some other command. You can disable the
3020 shortcut keys entirely by adding this line to ~/.OWdefaults:
3022 OpenWindows.WindowMenuAccelerators: False
3024 *** twm: A position you specified in .Xdefaults is ignored, using twm.
3026 twm normally ignores "program-specified" positions.
3027 You can tell it to obey them with this command in your '.twmrc' file:
3029 UsePPosition "on" #allow clients to request a position
3031 ** Bugs related to old DEC hardware
3033 *** The Compose key on a DEC keyboard does not work as Meta key.
3035 This shell command should fix it:
3037 xmodmap -e 'keycode 0xb1 = Meta_L'
3039 *** Keyboard input gets confused after a beep when using a DECserver
3042 This problem seems to be a matter of configuring the DECserver to use
3043 7 bit characters rather than 8 bit characters.
3045 This file is part of GNU Emacs.
3047 GNU Emacs is free software: you can redistribute it and/or modify
3048 it under the terms of the GNU General Public License as published by
3049 the Free Software Foundation, either version 3 of the License, or
3050 (at your option) any later version.
3052 GNU Emacs is distributed in the hope that it will be useful,
3053 but WITHOUT ANY WARRANTY; without even the implied warranty of
3054 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
3055 GNU General Public License for more details.
3057 You should have received a copy of the GNU General Public License
3058 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
3063 paragraph-separate: "[
\f]*$"