1 Known Problems with GNU Emacs
3 Copyright (C) 1987-1989, 1993-1999, 2001-2017 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 macOS, 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 *** TLS problems, e.g., Gnus hangs when fetching via imaps
613 http://debbugs.gnu.org/24247
615 gnutls-cli 3.5.3 (2016-08-09) does not generate a "- Handshake was
616 completed" message that tls.el relies upon, causing affected Emacs
617 functions to hang. To work around the problem, use older or newer
618 versions of gnutls-cli, or use Emacs's built-in gnutls support.
620 * Runtime problems related to font handling
622 ** Characters are displayed as empty boxes or with wrong font under X.
624 *** This can occur when two different versions of FontConfig are used.
625 For example, XFree86 4.3.0 has one version and Gnome usually comes
626 with a newer version. Emacs compiled with Gtk+ will then use the
627 newer version. In most cases the problem can be temporarily fixed by
628 stopping the application that has the error (it can be Emacs or any
629 other application), removing ~/.fonts.cache-1, and then starting the
630 application again. If removing ~/.fonts.cache-1 and restarting
631 doesn't help, the application with problem must be recompiled with the
632 same version of FontConfig as the rest of the system uses. For KDE,
633 it is sufficient to recompile Qt.
635 *** Some fonts have a missing glyph and no default character. This is
636 known to occur for character number 160 (no-break space) in some
637 fonts, such as Lucida but Emacs sets the display table for the unibyte
638 and Latin-1 version of this character to display a space.
640 *** Some of the fonts called for in your fontset may not exist on your
643 Each X font covers just a fraction of the characters that Emacs
644 supports. To display the whole range of Emacs characters requires
645 many different fonts, collected into a fontset. You can remedy the
646 problem by installing additional fonts.
648 The intlfonts distribution includes a full spectrum of fonts that can
649 display all the characters Emacs supports. The etl-unicode collection
650 of fonts (available from <URL:ftp://ftp.x.org/contrib/fonts/>) includes
651 fonts that can display many Unicode characters; they can also be used
652 by ps-print and ps-mule to print Unicode characters.
654 ** Under X, some characters appear improperly aligned in their lines.
656 You may have bad fonts.
658 ** Under X, an unexpected monospace font is used as the default font.
660 When compiled with XFT, Emacs tries to use a default font named
661 "monospace". This is a "virtual font", which the operating system
662 (Fontconfig) redirects to a suitable font such as DejaVu Sans Mono.
663 On some systems, there exists a font that is actually named Monospace,
664 which takes over the virtual font. This is considered an operating
667 http://lists.gnu.org/archive/html/emacs-devel/2008-10/msg00696.html
669 If you encounter this problem, set the default font to a specific font
670 in your .Xresources or initialization file. For instance, you can put
671 the following in your .Xresources:
673 Emacs.font: DejaVu Sans Mono 12
675 ** Certain fonts make each line take one pixel more than it should.
677 This is because these fonts contain characters a little taller than
678 the font's nominal height. Emacs needs to make sure that lines do not
681 ** Font Lock displays portions of the buffer in incorrect faces.
683 By far the most frequent cause of this is a parenthesis '(' or a brace
684 '{' in column zero. Font Lock assumes that such a paren is outside of
685 any comment or string. This is of course not true in general, but the
686 vast majority of well-formatted program source files don't have such
687 parens, and therefore this assumption is used to allow optimizations
688 in Font Lock's syntactical analysis. These optimizations avoid some
689 pathological cases where jit-lock, the Just-in-Time fontification
690 introduced with Emacs 21.1, could significantly slow down scrolling
691 through the buffer, especially scrolling backwards, and also jumping
692 to the end of a very large buffer.
694 Beginning with version 22.1, a parenthesis or a brace in column zero
695 is highlighted in bold-red face if it is inside a string or a comment,
696 to indicate that it could interfere with Font Lock (and also with
697 indentation) and should be moved or escaped with a backslash.
699 If you don't use large buffers, or have a very fast machine which
700 makes the delays insignificant, you can avoid the incorrect
701 fontification by setting the variable
702 'font-lock-beginning-of-syntax-function' to a nil value. (This must
703 be done _after_ turning on Font Lock.)
705 Another alternative is to avoid a paren in column zero. For example,
706 in a Lisp string you could precede the paren with a backslash.
708 ** Emacs pauses for several seconds when changing the default font.
710 This has been reported for fvwm 2.2.5 and the window manager of KDE
711 2.1. The reason for the pause is Xt waiting for a ConfigureNotify
712 event from the window manager, which the window manager doesn't send.
713 Xt stops waiting after a default timeout of usually 5 seconds.
715 A workaround for this is to add something like
717 emacs.waitForWM: false
719 to your X resources. Alternatively, add '(wait-for-wm . nil)' to a
720 frame's parameter list, like this:
722 (modify-frame-parameters nil '((wait-for-wm . nil)))
724 (this should go into your '.emacs' file).
726 ** Underlines appear at the wrong position.
728 This is caused by fonts having a wrong UNDERLINE_POSITION property.
729 Examples are the 7x13 font on XFree86 prior to version 4.1, or the jmk
730 neep font from the Debian xfonts-jmk package prior to version 3.0.17.
731 To circumvent this problem, set x-use-underline-position-properties
732 to nil in your '.emacs'.
734 To see what is the value of UNDERLINE_POSITION defined by the font,
735 type 'xlsfonts -lll FONT' and look at the font's UNDERLINE_POSITION property.
737 ** When using Exceed, fonts sometimes appear too tall.
739 When the display is set to an Exceed X-server and fonts are specified
740 (either explicitly with the -fn option or implicitly with X resources)
741 then the fonts may appear "too tall". The actual character sizes are
742 correct but there is too much vertical spacing between rows, which
743 gives the appearance of "double spacing".
745 To prevent this, turn off the Exceed's "automatic font substitution"
746 feature (in the font part of the configuration window).
748 ** Subscript/superscript text in TeX is hard to read.
750 If 'tex-fontify-script' is non-nil, tex-mode displays
751 subscript/superscript text in the faces subscript/superscript, which
752 are smaller than the normal font and lowered/raised. With some fonts,
753 nested superscripts (say) can be hard to read. Switching to a
754 different font, or changing your antialiasing setting (on an LCD
755 screen), can both make the problem disappear. Alternatively, customize
756 the following variables: tex-font-script-display (how much to
757 lower/raise); tex-suscript-height-ratio (how much smaller than
758 normal); tex-suscript-height-minimum (minimum height).
760 ** Screen refresh is slow when there are special characters for which no suitable font is available
762 If the display is too slow in refreshing when you scroll to a new
763 region, or when you edit the buffer, it might be due to the fact that
764 some characters cannot be displayed in the default font, and Emacs is
765 spending too much time in looking for a suitable font to display them.
767 You can suspect this if you have several characters that are displayed
768 as small rectangles containing a hexadecimal code inside.
770 The solution is to install the appropriate fonts on your machine. For
771 instance if you are editing a text with a lot of math symbols, then
772 installing a font like 'Symbola' should solve this problem.
774 * Internationalization problems
776 ** M-{ does not work on a Spanish PC keyboard.
778 Many Spanish keyboards seem to ignore that combination. Emacs can't
779 do anything about it.
781 ** International characters aren't displayed under X.
785 XFree86 4 contains many fonts in iso10646-1 encoding which have
786 minimal character repertoires (whereas the encoding part of the font
787 name is meant to be a reasonable indication of the repertoire
788 according to the XLFD spec). Emacs may choose one of these to display
789 characters from the mule-unicode charsets and then typically won't be
790 able to find the glyphs to display many characters. (Check with C-u
791 C-x = .) To avoid this, you may need to use a fontset which sets the
792 font for the mule-unicode sets explicitly. E.g. to use GNU unifont,
793 include in the fontset spec:
795 mule-unicode-2500-33ff:-gnu-unifont-*-iso10646-1,\
796 mule-unicode-e000-ffff:-gnu-unifont-*-iso10646-1,\
797 mule-unicode-0100-24ff:-gnu-unifont-*-iso10646-1
799 ** The UTF-8/16/7 coding systems don't encode CJK (Far Eastern) characters.
801 Emacs directly supports the Unicode BMP whose code points are in the
802 ranges 0000-33ff and e000-ffff, and indirectly supports the parts of
803 CJK characters belonging to these legacy charsets:
805 GB2312, Big5, JISX0208, JISX0212, JISX0213-1, JISX0213-2, KSC5601
807 The latter support is done in Utf-Translate-Cjk mode (turned on by
808 default). Which Unicode CJK characters are decoded into which Emacs
809 charset is decided by the current language environment. For instance,
810 in Chinese-GB, most of them are decoded into chinese-gb2312.
812 If you read UTF-8 data with code points outside these ranges, the
813 characters appear in the buffer as raw bytes of the original UTF-8
814 (composed into a single quasi-character) and they will be written back
815 correctly as UTF-8, assuming you don't break the composed sequences.
816 If you read such characters from UTF-16 or UTF-7 data, they are
817 substituted with the Unicode 'replacement character', and you lose
820 ** Accented ISO-8859-1 characters are displayed as | or _.
822 Try other font set sizes (S-mouse-1). If the problem persists with
823 other sizes as well, your text is corrupted, probably through software
824 that is not 8-bit clean. If the problem goes away with another font
825 size, it's probably because some fonts pretend to be ISO-8859-1 fonts
826 when they are really ASCII fonts. In particular the schumacher-clean
827 fonts have this bug in some versions of X.
829 To see what glyphs are included in a font, use 'xfd', like this:
831 xfd -fn -schumacher-clean-medium-r-normal--12-120-75-75-c-60-iso8859-1
833 If this shows only ASCII glyphs, the font is indeed the source of the problem.
835 The solution is to remove the corresponding lines from the appropriate
836 'fonts.alias' file, then run 'mkfontdir' in that directory, and then run
839 ** The 'oc-unicode' package doesn't work with Emacs 21.
841 This package tries to define more private charsets than there are free
842 slots now. The current built-in Unicode support is actually more
843 flexible. (Use option 'utf-translate-cjk-mode' if you need CJK
844 support.) Files encoded as emacs-mule using oc-unicode aren't
845 generally read correctly by Emacs 21.
849 ** X keyboard problems
851 *** You "lose characters" after typing Compose Character key.
853 This is because the Compose Character key is defined as the keysym
854 Multi_key, and Emacs (seeing that) does the proper X
855 character-composition processing. If you don't want your Compose key
856 to do that, you can redefine it with xmodmap.
858 For example, here's one way to turn it into a Meta key:
860 xmodmap -e "keysym Multi_key = Meta_L"
862 If all users at your site of a particular keyboard prefer Meta to
863 Compose, you can make the remapping happen automatically by adding the
864 xmodmap command to the xdm setup script for that display.
866 *** Using X Window System, control-shift-leftbutton makes Emacs hang.
868 Use the shell command 'xset bc' to make the old X Menu package work.
870 *** C-SPC fails to work on Fedora GNU/Linux (or with fcitx input method).
872 Fedora Core 4 steals the C-SPC key by default for the 'iiimx' program
873 which is the input method for some languages. It blocks Emacs users
874 from using the C-SPC key for 'set-mark-command'.
876 One solutions is to remove the '<Ctrl>space' from the 'Iiimx' file
877 which can be found in the '/usr/lib/X11/app-defaults' directory.
878 However, that requires root access.
880 Another is to specify 'Emacs*useXIM: false' in your X resources.
882 Another is to build Emacs with the '--without-xim' configure option.
884 The same problem happens on any other system if you are using fcitx
885 (Chinese input method) which by default use C-SPC for toggling. If
886 you want to use fcitx with Emacs, you have two choices. Toggle fcitx
887 by another key (e.g. C-\) by modifying ~/.fcitx/config, or be
888 accustomed to use C-@ for 'set-mark-command'.
890 *** Link-time optimization with clang doesn't work on Fedora 20.
892 As of May 2014, Fedora 20 has broken LLVMgold.so plugin support in clang
893 (tested with clang-3.4-6.fc20) - 'clang --print-file-name=LLVMgold.so'
894 prints 'LLVMgold.so' instead of full path to plugin shared library, and
895 'clang -flto' is unable to find the plugin with the following error:
897 /bin/ld: error: /usr/bin/../lib/LLVMgold.so: could not load plugin library:
898 /usr/bin/../lib/LLVMgold.so: cannot open shared object file: No such file
901 The only way to avoid this is to build your own clang from source code
902 repositories, as described at http://clang.llvm.org/get_started.html.
904 *** M-SPC seems to be ignored as input.
906 See if your X server is set up to use this as a command
907 for character composition.
909 *** The S-C-t key combination doesn't get passed to Emacs on X.
911 This happens because some X configurations assign the Ctrl-Shift-t
912 combination the same meaning as the Multi_key. The offending
913 definition is in the file '...lib/X11/locale/iso8859-1/Compose'; there
914 might be other similar combinations which are grabbed by X for similar
917 We think that this can be countermanded with the 'xmodmap' utility, if
918 you want to be able to bind one of these key sequences within Emacs.
920 *** Under X, C-v and/or other keys don't work.
922 These may have been intercepted by your window manager.
923 See the WM's documentation for how to change this.
925 *** Clicking C-mouse-2 in the scroll bar doesn't split the window.
927 This currently doesn't work with scroll-bar widgets (and we don't know
928 a good way of implementing it with widgets). If Emacs is configured
929 --without-toolkit-scroll-bars, C-mouse-2 on the scroll bar does work.
931 *** Inability to send an Alt-modified key, when Emacs is communicating
932 directly with an X server.
934 If you have tried to bind an Alt-modified key as a command, and it
935 does not work to type the command, the first thing you should check is
936 whether the key is getting through to Emacs. To do this, type C-h c
937 followed by the Alt-modified key. C-h c should say what kind of event
938 it read. If it says it read an Alt-modified key, then make sure you
939 have made the key binding correctly.
941 If C-h c reports an event that doesn't have the Alt modifier, it may
942 be because your X server has no key for the Alt modifier. The X
943 server that comes from MIT does not set up the Alt modifier by default.
945 If your keyboard has keys named Alt, you can enable them as follows:
947 xmodmap -e 'add mod2 = Alt_L'
948 xmodmap -e 'add mod2 = Alt_R'
950 If the keyboard has just one key named Alt, then only one of those
951 commands is needed. The modifier 'mod2' is a reasonable choice if you
952 are using an unmodified MIT version of X. Otherwise, choose any
953 modifier bit not otherwise used.
955 If your keyboard does not have keys named Alt, you can use some other
956 keys. Use the keysym command in xmodmap to turn a function key (or
957 some other 'spare' key) into Alt_L or into Alt_R, and then use the
958 commands show above to make them modifier keys.
960 Note that if you have Alt keys but no Meta keys, Emacs translates Alt
961 into Meta. This is because of the great importance of Meta in Emacs.
963 ** Window-manager and toolkit-related problems
965 *** Emacs built with GTK+ toolkit produces corrupted display on HiDPI screen
967 This can happen if you set GDK_SCALE=2 in the environment or in your
968 '.xinitrc' file. (This setting is usually accompanied by
969 GDK_DPI_SCALE=0.5.) Emacs can not support these settings correctly,
970 as it doesn't use GTK+ exclusively. The result is that sometimes
971 widgets like the scroll bar are displayed incorrectly, and frames
972 could be displayed "cropped" to only part of the stuff that should be
975 The workaround is to explicitly disable these settings when invoking
976 Emacs, for example (from a Posix shell prompt):
978 $ GDK_SCALE=1 GDK_DPI_SCALE=1 emacs
980 *** Emacs built with GTK+ toolkit can unexpectedly widen frames
982 This resizing takes place when a frame is not wide enough to accommodate
983 its entire menu bar. Typically, it occurs when switching buffers or
984 changing a buffer's major mode and the new mode adds entries to the menu
985 bar. The frame is then widened by the window manager so that the menu
986 bar is fully shown. Subsequently switching to another buffer or
987 changing the buffer's mode will not shrink the frame back to its
988 previous width. The height of the frame remains unaltered. Apparently,
989 the failure is also dependent on the chosen font.
991 The resizing is usually accompanied by console output like
993 Gtk-CRITICAL **: gtk_distribute_natural_allocation: assertion 'extra_space >= 0' failed
995 It's not clear whether the GTK version used has any impact on the
996 occurrence of the failure. So far, the failure has been observed with
997 GTK+ versions 3.4.2, 3.14.5 and 3.18.7. However, another 3.4.2 build
998 does not exhibit the bug.
1000 Some window managers (Xfce) apparently work around this failure by
1001 cropping the menu bar. With other windows managers, it's possible to
1002 shrink the frame manually after the problem occurs, e.g. by dragging the
1003 frame's border with the mouse. However, some window managers have been
1004 reported to refuse such attempts and snap back to the width needed to
1005 show the full menu bar (wmii) or at least cause the screen to flicker
1006 during such resizing attempts (i3, IceWM).
1008 See also http://debbugs.gnu.org/cgi/bugreport.cgi?bug=15700,
1009 http://debbugs.gnu.org/cgi/bugreport.cgi?bug=22000,
1010 http://debbugs.gnu.org/cgi/bugreport.cgi?bug=22898 and
1011 http://lists.gnu.org/archive/html/emacs-devel/2016-07/msg00154.html.
1013 *** Metacity: Resizing Emacs or ALT-Tab causes X to be unresponsive.
1015 This happens sometimes when using Metacity. Resizing Emacs or ALT-Tab:bing
1016 makes the system unresponsive to the mouse or the keyboard. Killing Emacs
1017 or shifting out from X and back again usually cures it (i.e. Ctrl-Alt-F1
1018 and then Alt-F7). A bug for it is here:
1019 https://bugs.launchpad.net/ubuntu/+source/metacity/+bug/231034.
1020 Note that a permanent fix seems to be to disable "assistive technologies".
1022 *** Gnome: Emacs receives input directly from the keyboard, bypassing XIM.
1024 This seems to happen when gnome-settings-daemon version 2.12 or later
1025 is running. If gnome-settings-daemon is not running, Emacs receives
1026 input through XIM without any problem. Furthermore, this seems only
1027 to happen in *.UTF-8 locales; zh_CN.GB2312 and zh_CN.GBK locales, for
1028 example, work fine. A bug report has been filed in the Gnome
1029 bugzilla: http://bugzilla.gnome.org/show_bug.cgi?id=357032
1031 *** Gnome: Emacs's xterm-mouse-mode doesn't work on the Gnome terminal.
1033 A symptom of this bug is that double-clicks insert a control sequence
1034 into the buffer. The reason this happens is an apparent
1035 incompatibility of the Gnome terminal with Xterm, which also affects
1036 other programs using the Xterm mouse interface. A problem report has
1039 *** KDE: When running on KDE, colors or fonts are not as specified for Emacs,
1042 For example, you could see background you set for Emacs only in the
1043 empty portions of the Emacs display, while characters have some other
1046 This happens because KDE's defaults apply its color and font
1047 definitions even to applications that weren't compiled for KDE. The
1048 solution is to uncheck the "Apply fonts and colors to non-KDE apps"
1049 option in Preferences->Look&Feel->Style (KDE 2). In KDE 3, this option
1050 is in the "Colors" section, rather than "Style".
1052 Alternatively, if you do want the KDE defaults to apply to other
1053 applications, but not to Emacs, you could modify the file 'Emacs.ad'
1054 (should be in the '/usr/share/apps/kdisplay/app-defaults/' directory)
1055 so that it doesn't set the default background and foreground only for
1056 Emacs. For example, make sure the following resources are either not
1057 present or commented out:
1059 Emacs.default.attributeForeground
1060 Emacs.default.attributeBackground
1064 It is also reported that a bug in the gtk-engines-qt engine can cause this if
1065 Emacs is compiled with Gtk+.
1066 The bug is fixed in version 0.7 or newer of gtk-engines-qt.
1068 *** KDE: Emacs hangs on KDE when a large portion of text is killed.
1070 This is caused by a bug in the KDE applet 'klipper' which periodically
1071 requests the X clipboard contents from applications. Early versions
1072 of klipper don't implement the ICCCM protocol for large selections,
1073 which leads to Emacs being flooded with selection requests. After a
1074 while, Emacs may print a message:
1076 Timed out waiting for property-notify event
1078 A workaround is to not use 'klipper'. Upgrading 'klipper' to the one
1079 coming with KDE 3.3 or later also solves the problem.
1081 *** KDE / Plasma 5: Emacs exhausts memory and needs to be killed
1083 This problem occurs when large selections contain mixed line endings
1084 (i.e. the buffer has LF line endings, but in some parts CRLF is used).
1085 The source of the problem is currently under investigation, older
1086 versions of Emacs up to 24.5 just hang for a few seconds and then
1087 return with the message "Timed out waiting for property-notify event"
1088 as described in the previous note. As a workaround, go to the
1089 settings dialog for the Clipboard widget and select the option "Ignore
1092 Note: Plasma 5 has replaced the separate klipper process from earlier
1093 KDE versions with functionality directly integrated into plasmashell,
1094 so even if you've previously did not use klipper this will affect you.
1095 Also, all configuration you might have done to klipper is not used by
1096 the new Clipboard widget / plasmoid since it uses its own settings.
1097 You can hide the Clipboard widget by removing its entry from the
1098 system tray settings "Extra Items", but it's not clear if the
1099 underlying functionality in plasmashell gets fully disabled as well.
1100 At least a restart of plasmashell is required for the clipboard
1101 history to be cleared.
1103 *** CDE: Frames may cover dialogs they created when using CDE.
1105 This can happen if you have "Allow Primary Windows On Top" enabled which
1106 seems to be the default in the Common Desktop Environment.
1107 To change, go in to "Desktop Controls" -> "Window Style Manager"
1108 and uncheck "Allow Primary Windows On Top".
1110 *** Xaw3d : When using Xaw3d scroll bars without arrows, the very first mouse
1111 click in a scroll bar might be ignored by the scroll bar widget. This
1112 is probably a bug in Xaw3d; when Xaw3d is compiled with arrows, the
1115 *** Xaw: There are known binary incompatibilities between Xaw, Xaw3d, neXtaw,
1116 XawM and the few other derivatives of Xaw. So when you compile with
1117 one of these, it may not work to dynamically link with another one.
1118 For example, strange problems, such as Emacs exiting when you type
1119 "C-x 1", were reported when Emacs compiled with Xaw3d and libXaw was
1120 used with neXtaw at run time.
1122 The solution is to rebuild Emacs with the toolkit version you actually
1123 want to use, or set LD_PRELOAD to preload the same toolkit version you
1126 *** Open Motif: Problems with file dialogs in Emacs built with Open Motif.
1128 When Emacs 21 is built with Open Motif 2.1, it can happen that the
1129 graphical file dialog boxes do not work properly. The "OK", "Filter"
1130 and "Cancel" buttons do not respond to mouse clicks. Dragging the
1131 file dialog window usually causes the buttons to work again.
1133 As a workaround, you can try building Emacs using Motif or LessTif instead.
1135 Another workaround is not to use the mouse to trigger file prompts,
1136 but to use the keyboard. This way, you will be prompted for a file in
1137 the minibuffer instead of a graphical file dialog.
1139 *** LessTif: Problems in Emacs built with LessTif.
1141 The problems seem to depend on the version of LessTif and the Motif
1142 emulation for which it is set up.
1144 Only the Motif 1.2 emulation seems to be stable enough in LessTif.
1145 LessTif 0.92-17's Motif 1.2 emulation seems to work okay on FreeBSD.
1146 On GNU/Linux systems, lesstif-0.92.6 configured with "./configure
1147 --enable-build-12 --enable-default-12" is reported to be the most
1148 successful. The binary GNU/Linux package
1149 lesstif-devel-0.92.0-1.i386.rpm was reported to have problems with
1152 On some systems, Emacs occasionally locks up, grabbing all mouse and
1153 keyboard events. We don't know what causes these problems; they are
1154 not reproducible by Emacs developers.
1156 *** Motif: The Motif version of Emacs paints the screen a solid color.
1158 This has been observed to result from the following X resource:
1160 Emacs*default.attributeFont: -*-courier-medium-r-*-*-*-140-*-*-*-*-iso8859-*
1162 That the resource has this effect indicates a bug in something, but we
1163 do not know what. If it is an Emacs bug, we hope someone can
1164 explain what the bug is so we can fix it. In the mean time, removing
1165 the resource prevents the problem.
1167 ** General X problems
1169 *** Redisplay using X is much slower than previous Emacs versions.
1171 We've noticed that certain X servers draw the text much slower when
1172 scroll bars are on the left. We don't know why this happens. If this
1173 happens to you, you can work around it by putting the scroll bars
1174 on the right (as they were in Emacs 19).
1176 Here's how to do this:
1178 (set-scroll-bar-mode 'right)
1180 If you're not sure whether (or how much) this problem affects you,
1181 try that and see how much difference it makes. To set things back
1184 (set-scroll-bar-mode 'left)
1186 *** Error messages about undefined colors on X.
1188 The messages might say something like this:
1190 Unable to load color "grey95"
1192 (typically, in the '*Messages*' buffer), or something like this:
1194 Error while displaying tooltip: (error Undefined color lightyellow)
1196 These problems could happen if some other X program has used up too
1197 many colors of the X palette, leaving Emacs with insufficient system
1198 resources to load all the colors it needs.
1200 A solution is to exit the offending X programs before starting Emacs.
1202 "undefined color" messages can also occur if the RgbPath entry in the
1203 X configuration file is incorrect, or the rgb.txt file is not where
1204 X expects to find it.
1206 *** Improving performance with slow X connections.
1208 There are several ways to improve this performance, any subset of which can
1209 be carried out at the same time:
1211 1) If you don't need X Input Methods (XIM) for entering text in some
1212 language you use, you can improve performance on WAN links by using
1213 the X resource useXIM to turn off use of XIM. This does not affect
1214 the use of Emacs's own input methods, which are part of the Leim
1217 2) If the connection is very slow, you might also want to consider
1218 switching off scroll bars, menu bar, and tool bar. Adding the
1219 following forms to your .emacs file will accomplish that, but only
1220 after the initial frame is displayed:
1222 (scroll-bar-mode -1)
1226 For still quicker startup, put these X resources in your
1227 .Xresources or .Xdefaults file:
1229 Emacs.verticalScrollBars: off
1233 3) Use ssh to forward the X connection, and enable compression on this
1234 forwarded X connection (ssh -XC remotehostname emacs ...).
1236 4) Use lbxproxy on the remote end of the connection. This is an interface
1237 to the low bandwidth X extension in most modern X servers, which
1238 improves performance dramatically, at the slight expense of correctness
1239 of the X protocol. lbxproxy achieves the performance gain by grouping
1240 several X requests in one TCP packet and sending them off together,
1241 instead of requiring a round-trip for each X request in a separate
1242 packet. The switches that seem to work best for emacs are:
1243 -noatomsfile -nowinattr -cheaterrors -cheatevents
1244 Note that the -nograbcmap option is known to cause problems.
1245 For more about lbxproxy, see:
1246 http://www.x.org/archive/X11R6.8.0/doc/lbxproxy.1.html
1248 5) If copying and killing is slow, try to disable the interaction with the
1249 native system's clipboard by adding these lines to your .emacs file:
1250 (setq interprogram-cut-function nil)
1251 (setq interprogram-paste-function nil)
1253 *** Emacs gives the error, Couldn't find per display information.
1255 This can result if the X server runs out of memory because Emacs uses
1256 a large number of fonts. On systems where this happens, C-h h is
1259 We do not know of a way to prevent the problem.
1261 *** Emacs does not notice when you release the mouse.
1263 There are reports that this happened with (some) Microsoft mice and
1264 that replacing the mouse made it stop.
1266 *** You can't select from submenus (in the X toolkit version).
1268 On certain systems, mouse-tracking and selection in top-level menus
1269 works properly with the X toolkit, but neither of them works when you
1270 bring up a submenu (such as Bookmarks or Compare or Apply Patch, in
1273 This works on most systems. There is speculation that the failure is
1274 due to bugs in old versions of X toolkit libraries, but no one really
1275 knows. If someone debugs this and finds the precise cause, perhaps a
1276 workaround can be found.
1278 *** An error message such as 'X protocol error: BadMatch (invalid
1279 parameter attributes) on protocol request 93'.
1281 This comes from having an invalid X resource, such as
1283 (which is invalid because it specifies a color name for something
1284 that isn't a color.)
1286 The fix is to correct your X resources.
1288 *** Slow startup on X11R6 with X windows.
1290 If Emacs takes two minutes to start up on X11R6, see if your X
1291 resources specify any Adobe fonts. That causes the type-1 font
1292 renderer to start up, even if the font you asked for is not a type-1
1295 One way to avoid this problem is to eliminate the type-1 fonts from
1296 your font path, like this:
1298 xset -fp /usr/X11R6/lib/X11/fonts/Type1/
1300 *** Pull-down menus appear in the wrong place, in the toolkit version of Emacs.
1302 An X resource of this form can cause the problem:
1304 Emacs*geometry: 80x55+0+0
1306 This resource is supposed to apply, and does apply, to the menus
1307 individually as well as to Emacs frames. If that is not what you
1308 want, rewrite the resource.
1310 To check thoroughly for such resource specifications, use 'xrdb
1311 -query' to see what resources the X server records, and also look at
1312 the user's ~/.Xdefaults and ~/.Xdefaults-* files.
1314 *** Emacs running under X Window System does not handle mouse clicks.
1315 *** 'emacs -geometry 80x20' finds a file named '80x20'.
1317 One cause of such problems is having (setq term-file-prefix nil) in
1318 your .emacs file. Another cause is a bad value of EMACSLOADPATH in
1321 *** X doesn't work if DISPLAY uses a hostname.
1323 People have reported kernel bugs in certain systems that cause Emacs
1324 not to work with X if DISPLAY is set using a host name. But
1325 the problem does not occur if DISPLAY is set to 'unix:0.0'. I think
1326 the bug has to do with SIGIO or FIONREAD.
1328 You may be able to compensate for the bug by doing (set-input-mode nil nil).
1329 However, that has the disadvantage of turning off interrupts, so that
1330 you are unable to quit out of a Lisp program by typing C-g.
1332 *** Prevent double pastes in X
1334 The problem: a region, such as a command, is pasted twice when you copy
1335 it with your mouse from GNU Emacs to an xterm or an RXVT shell in X.
1336 The solution: try the following in your X configuration file,
1337 /etc/X11/xorg.conf This should enable both PS/2 and USB mice for
1338 single copies. You do not need any other drivers or options.
1340 Section "InputDevice"
1341 Identifier "Generic Mouse"
1343 Option "Device" "/dev/input/mice"
1346 *** Emacs is slow to exit in X
1348 After you use e.g. C-x C-c to exit, it takes many seconds before the
1349 Emacs window disappears. If Emacs was started from a terminal, you
1352 Error saving to X clipboard manager.
1353 If the problem persists, set 'x-select-enable-clipboard-manager' to nil.
1355 As the message suggests, this problem occurs when Emacs thinks you
1356 have a clipboard manager program running, but has trouble contacting it.
1357 If you don't want to use a clipboard manager, you can set the
1358 suggested variable. Or you can make Emacs not wait so long by
1359 reducing the value of 'x-selection-timeout', either in .emacs or with
1362 Sometimes this problem is due to a bug in your clipboard manager.
1363 Updating to the latest version of the manager can help.
1364 For example, in the Xfce 4.8 desktop environment, the clipboard
1365 manager in versions of xfce4-settings-helper before 4.8.2 is buggy;
1366 https://bugzilla.xfce.org/show_bug.cgi?id=7588 .
1368 *** Warning messages when running in Ubuntu
1370 When you start Emacs you may see something like this:
1372 (emacs:2286): LIBDBUSMENU-GTK-CRITICAL **: watch_submenu: assertion
1373 'GTK_IS_MENU_SHELL(menu)' failed
1375 This happens if the Emacs binary has been renamed. The cause is the Ubuntu
1376 appmenu concept. It tries to track Emacs menus and show them in the top
1377 panel, instead of in each Emacs window. This is not properly implemented,
1378 so it fails for Emacs. The order of menus is wrong, and things like copy/paste
1379 that depend on what state Emacs is in are usually wrong (i.e. paste disabled
1380 even if you should be able to paste, and similar).
1382 You can get back menus on each frame by starting emacs like this:
1383 % env UBUNTU_MENUPROXY= emacs
1385 * Runtime problems on character terminals
1387 ** The meta key does not work on xterm.
1389 Typing M-x rings the terminal bell, and inserts a string like ";120~".
1390 For recent xterm versions (>= 216), Emacs uses xterm's modifyOtherKeys
1391 feature to generate strings for key combinations that are not
1392 otherwise usable. One circumstance in which this can cause problems
1393 is if you have specified the X resource
1395 xterm*VT100.Translations
1397 to contain translations that use the meta key. Then xterm will not
1398 use meta in modified function-keys, which confuses Emacs. To fix
1399 this, you can remove the X resource or put this in your init file:
1401 (xterm-remove-modify-other-keys)
1403 ** Emacs spontaneously displays "I-search: " at the bottom of the screen.
1405 This means that Control-S/Control-Q (XON/XOFF) "flow control" is being
1406 used. C-s/C-q flow control is bad for Emacs editors because it takes
1407 away C-s and C-q as user commands. Since editors do not output long
1408 streams of text without user commands, there is no need for a
1409 user-issuable "stop output" command in an editor; therefore, a
1410 properly designed flow control mechanism would transmit all possible
1411 input characters without interference. Designing such a mechanism is
1412 easy, for a person with at least half a brain.
1414 There are three possible reasons why flow control could be taking place:
1416 1) Terminal has not been told to disable flow control
1417 2) Insufficient padding for the terminal in use
1418 3) Some sort of terminal concentrator or line switch is responsible
1420 First of all, many terminals have a set-up mode which controls whether
1421 they generate XON/XOFF flow control characters. This must be set to
1422 "no XON/XOFF" in order for Emacs to work. (For example, on a VT220
1423 you may select "No XOFF" in the setup menu.) Sometimes there is an
1424 escape sequence that the computer can send to turn flow control off
1425 and on. If so, perhaps the termcap 'ti' string should turn flow
1426 control off, and the 'te' string should turn it on.
1428 Once the terminal has been told "no flow control", you may find it
1429 needs more padding. The amount of padding Emacs sends is controlled
1430 by the termcap entry for the terminal in use, and by the output baud
1431 rate as known by the kernel. The shell command 'stty' will print
1432 your output baud rate; 'stty' with suitable arguments will set it if
1433 it is wrong. Setting to a higher speed causes increased padding. If
1434 the results are wrong for the correct speed, there is probably a
1435 problem in the termcap entry. You must speak to a local Unix wizard
1436 to fix this. Perhaps you are just using the wrong terminal type.
1438 For terminals that lack a "no flow control" mode, sometimes just
1439 giving lots of padding will prevent actual generation of flow control
1440 codes. You might as well try it.
1442 If you are really unlucky, your terminal is connected to the computer
1443 through a concentrator which sends XON/XOFF flow control to the
1444 computer, or it insists on sending flow control itself no matter how
1445 much padding you give it. Unless you can figure out how to turn flow
1446 control off on this concentrator (again, refer to your local wizard),
1447 you are screwed! You should have the terminal or concentrator
1448 replaced with a properly designed one. In the mean time, some drastic
1449 measures can make Emacs semi-work.
1451 You can make Emacs ignore C-s and C-q and let the operating system
1452 handle them. To do this on a per-session basis, just type M-x
1453 enable-flow-control RET. You will see a message that C-\ and C-^ are
1454 now translated to C-s and C-q. (Use the same command M-x
1455 enable-flow-control to turn *off* this special mode. It toggles flow
1458 If C-\ and C-^ are inconvenient for you (for example, if one of them
1459 is the escape character of your terminal concentrator), you can choose
1460 other characters by setting the variables flow-control-c-s-replacement
1461 and flow-control-c-q-replacement. But choose carefully, since all
1462 other control characters are already used by emacs.
1464 IMPORTANT: if you type C-s by accident while flow control is enabled,
1465 Emacs output will freeze, and you will have to remember to type C-q in
1468 If you work in an environment where a majority of terminals of a
1469 certain type are flow control hobbled, you can use the function
1470 'enable-flow-control-on' to turn on this flow control avoidance scheme
1471 automatically. Here is an example:
1473 (enable-flow-control-on "vt200" "vt300" "vt101" "vt131")
1475 If this isn't quite correct (e.g. you have a mixture of flow-control hobbled
1476 and good vt200 terminals), you can still run enable-flow-control
1479 I have no intention of ever redesigning the Emacs command set for the
1480 assumption that terminals use C-s/C-q flow control. XON/XOFF flow
1481 control technique is a bad design, and terminals that need it are bad
1482 merchandise and should not be purchased. Now that X is becoming
1483 widespread, XON/XOFF seems to be on the way out. If you can get some
1484 use out of GNU Emacs on inferior terminals, more power to you, but I
1485 will not make Emacs worse for properly designed systems for the sake
1486 of inferior systems.
1488 ** Control-S and Control-Q commands are ignored completely.
1490 For some reason, your system is using brain-damaged C-s/C-q flow
1491 control despite Emacs's attempts to turn it off. Perhaps your
1492 terminal is connected to the computer through a concentrator
1493 that wants to use flow control.
1495 You should first try to tell the concentrator not to use flow control.
1496 If you succeed in this, try making the terminal work without
1497 flow control, as described in the preceding section.
1499 If that line of approach is not successful, map some other characters
1500 into C-s and C-q using keyboard-translate-table. The example above
1501 shows how to do this with C-^ and C-\.
1503 ** Screen is updated wrong, but only on one kind of terminal.
1505 This could mean that the termcap entry you are using for that
1506 terminal is wrong, or it could mean that Emacs has a bug handling
1507 the combination of features specified for that terminal.
1509 The first step in tracking this down is to record what characters
1510 Emacs is sending to the terminal. Execute the Lisp expression
1511 (open-termscript "./emacs-script") to make Emacs write all
1512 terminal output into the file ~/emacs-script as well; then do
1513 what makes the screen update wrong, and look at the file
1514 and decode the characters using the manual for the terminal.
1515 There are several possibilities:
1517 1) The characters sent are correct, according to the terminal manual.
1519 In this case, there is no obvious bug in Emacs, and most likely you
1520 need more padding, or possibly the terminal manual is wrong.
1522 2) The characters sent are incorrect, due to an obscure aspect
1523 of the terminal behavior not described in an obvious way by termcap.
1525 This case is hard. It will be necessary to think of a way for
1526 Emacs to distinguish between terminals with this kind of behavior
1527 and other terminals that behave subtly differently but are
1528 classified the same by termcap; or else find an algorithm for
1529 Emacs to use that avoids the difference. Such changes must be
1530 tested on many kinds of terminals.
1532 3) The termcap entry is wrong.
1534 See the file etc/TERMS for information on changes
1535 that are known to be needed in commonly used termcap entries
1536 for certain terminals.
1538 4) The characters sent are incorrect, and clearly cannot be
1539 right for any terminal with the termcap entry you were using.
1541 This is unambiguously an Emacs bug, and can probably be fixed
1542 in termcap.c, tparam.c, term.c, scroll.c, cm.c or dispnew.c.
1544 ** Control-S and Control-Q commands are ignored completely on a net connection.
1546 Some versions of rlogin (and possibly telnet) do not pass flow
1547 control characters to the remote system to which they connect.
1548 On such systems, emacs on the remote system cannot disable flow
1549 control on the local system. Sometimes 'rlogin -8' will avoid this problem.
1551 One way to cure this is to disable flow control on the local host
1552 (the one running rlogin, not the one running rlogind) using the
1553 stty command, before starting the rlogin process. On many systems,
1554 "stty start u stop u" will do this. On some systems, use
1555 "stty -ixon" instead.
1557 Some versions of tcsh will prevent even this from working. One way
1558 around this is to start another shell before starting rlogin, and
1559 issue the stty command to disable flow control from that shell.
1561 If none of these methods work, the best solution is to type
1562 M-x enable-flow-control at the beginning of your emacs session, or
1563 if you expect the problem to continue, add a line such as the
1564 following to your .emacs (on the host running rlogind):
1566 (enable-flow-control-on "vt200" "vt300" "vt101" "vt131")
1568 See the entry about spontaneous display of I-search (above) for more info.
1570 ** Output from Control-V is slow.
1572 On many bit-map terminals, scrolling operations are fairly slow.
1573 Often the termcap entry for the type of terminal in use fails
1574 to inform Emacs of this. The two lines at the bottom of the screen
1575 before a Control-V command are supposed to appear at the top after
1576 the Control-V command. If Emacs thinks scrolling the lines is fast,
1577 it will scroll them to the top of the screen.
1579 If scrolling is slow but Emacs thinks it is fast, the usual reason is
1580 that the termcap entry for the terminal you are using does not
1581 specify any padding time for the 'al' and 'dl' strings. Emacs
1582 concludes that these operations take only as much time as it takes to
1583 send the commands at whatever line speed you are using. You must
1584 fix the termcap entry to specify, for the 'al' and 'dl', as much
1585 time as the operations really take.
1587 Currently Emacs thinks in terms of serial lines which send characters
1588 at a fixed rate, so that any operation which takes time for the
1589 terminal to execute must also be padded. With bit-map terminals
1590 operated across networks, often the network provides some sort of
1591 flow control so that padding is never needed no matter how slow
1592 an operation is. You must still specify a padding time if you want
1593 Emacs to realize that the operation takes a long time. This will
1594 cause padding characters to be sent unnecessarily, but they do
1595 not really cost much. They will be transmitted while the scrolling
1596 is happening and then discarded quickly by the terminal.
1598 Most bit-map terminals provide commands for inserting or deleting
1599 multiple lines at once. Define the 'AL' and 'DL' strings in the
1600 termcap entry to say how to do these things, and you will have
1601 fast output without wasted padding characters. These strings should
1602 each contain a single %-spec saying how to send the number of lines
1603 to be scrolled. These %-specs are like those in the termcap
1606 You should also define the 'IC' and 'DC' strings if your terminal
1607 has a command to insert or delete multiple characters. These
1608 take the number of positions to insert or delete as an argument.
1610 A 'cs' string to set the scrolling region will reduce the amount
1611 of motion you see on the screen when part of the screen is scrolled.
1613 ** You type Control-H (Backspace) expecting to delete characters.
1615 Put 'stty dec' in your .login file and your problems will disappear
1618 The choice of Backspace for erasure was based on confusion, caused by
1619 the fact that backspacing causes erasure (later, when you type another
1620 character) on most display terminals. But it is a mistake. Deletion
1621 of text is not the same thing as backspacing followed by failure to
1622 overprint. I do not wish to propagate this confusion by conforming
1625 For this reason, I believe 'stty dec' is the right mode to use,
1626 and I have designed Emacs to go with that. If there were a thousand
1627 other control characters, I would define Control-h to delete as well;
1628 but there are not very many other control characters, and I think
1629 that providing the most mnemonic possible Help character is more
1630 important than adapting to people who don't use 'stty dec'.
1632 If you are obstinate about confusing buggy overprinting with deletion,
1633 you can redefine Backspace in your .emacs file:
1634 (global-set-key "\b" 'delete-backward-char)
1635 You can probably access help-command via f1.
1637 ** Colors are not available on a tty or in xterm.
1639 Emacs 21 supports colors on character terminals and terminal
1640 emulators, but this support relies on the terminfo or termcap database
1641 entry to specify that the display supports color. Emacs looks at the
1642 "Co" capability for the terminal to find out how many colors are
1643 supported; it should be non-zero to activate the color support within
1644 Emacs. (Most color terminals support 8 or 16 colors.) If your system
1645 uses terminfo, the name of the capability equivalent to "Co" is
1648 In addition to the "Co" capability, Emacs needs the "op" (for
1649 "original pair") capability, which tells how to switch the terminal
1650 back to the default foreground and background colors. Emacs will not
1651 use colors if this capability is not defined. If your terminal entry
1652 doesn't provide such a capability, try using the ANSI standard escape
1653 sequence \E[00m (that is, define a new termcap/terminfo entry and make
1654 it use your current terminal's entry plus \E[00m for the "op"
1657 Finally, the "NC" capability (terminfo name: "ncv") tells Emacs which
1658 attributes cannot be used with colors. Setting this capability
1659 incorrectly might have the effect of disabling colors; try setting
1660 this capability to '0' (zero) and see if that helps.
1662 Emacs uses the database entry for the terminal whose name is the value
1663 of the environment variable TERM. With 'xterm', a common terminal
1664 entry that supports color is 'xterm-color', so setting TERM's value to
1665 'xterm-color' might activate the color support on an xterm-compatible
1668 Beginning with version 22.1, Emacs supports the --color command-line
1669 option which may be used to force Emacs to use one of a few popular
1670 modes for getting colors on a tty. For example, --color=ansi8 sets up
1671 for using the ANSI-standard escape sequences that support 8 colors.
1673 Some modes do not use colors unless you turn on the Font-lock mode.
1674 Some people have long ago set their '~/.emacs' files to turn on
1675 Font-lock on X only, so they won't see colors on a tty. The
1676 recommended way of turning on Font-lock is by typing "M-x
1677 global-font-lock-mode RET" or by customizing the variable
1678 'global-font-lock-mode'.
1680 ** Unexpected characters inserted into the buffer when you start Emacs.
1681 See e.g. <URL:http://debbugs.gnu.org/11129>
1683 This can happen when you start Emacs in -nw mode in an Xterm.
1684 For example, in the *scratch* buffer, you might see something like:
1688 This is more likely to happen if you are using Emacs over a slow
1689 connection, and begin typing before Emacs is ready to respond.
1691 This occurs when Emacs tries to query the terminal to see what
1692 capabilities it supports, and gets confused by the answer.
1693 To avoid it, set xterm-extra-capabilities to a value other than
1694 'check' (the default). See that variable's documentation (in
1695 term/xterm.el) for more details.
1697 * Runtime problems specific to individual Unix variants
1701 *** GNU/Linux: Process output is corrupted.
1703 There is a bug in Linux kernel 2.6.10 PTYs that can cause emacs to
1704 read corrupted process output.
1706 *** GNU/Linux: Remote access to CVS with SSH causes file corruption.
1708 If you access a remote CVS repository via SSH, files may be corrupted
1709 due to bad interaction between CVS, SSH, and libc.
1711 To fix the problem, save the following script into a file, make it
1712 executable, and set CVS_RSH environment variable to the file name of
1716 exec 2> >(exec cat >&2 2>/dev/null)
1719 *** GNU/Linux: Truncated svn annotate output with SSH.
1720 http://debbugs.gnu.org/7791
1722 The symptoms are: you are accessing a svn repository over SSH.
1723 You use vc-annotate on a large (several thousand line) file, and the
1724 result is truncated around the 1000 line mark. It works fine with
1725 other access methods (e.g. http), or from outside Emacs.
1727 This may be a similar libc/SSH issue to the one mentioned above for CVS.
1728 A similar workaround seems to be effective: create a script with the
1729 same contents as the one used above for CVS_RSH, and set the SVN_SSH
1730 environment variable to point to it.
1732 *** GNU/Linux: After upgrading to a newer version of Emacs,
1733 the Meta key stops working.
1735 This was reported to happen on a GNU/Linux system distributed by
1736 Mandrake. The reason is that the previous version of Emacs was
1737 modified by Mandrake to make the Alt key act as the Meta key, on a
1738 keyboard where the Windows key is the one which produces the Meta
1739 modifier. A user who started using a newer version of Emacs, which
1740 was not hacked by Mandrake, expected the Alt key to continue to act as
1741 Meta, and was astonished when that didn't happen.
1743 The solution is to find out what key on your keyboard produces the Meta
1744 modifier, and use that key instead. Try all of the keys to the left
1745 and to the right of the space bar, together with the 'x' key, and see
1746 which combination produces "M-x" in the echo area. You can also use
1747 the 'xmodmap' utility to show all the keys which produce a Meta
1750 xmodmap -pk | grep -Ei "meta|alt"
1752 A more convenient way of finding out which keys produce a Meta modifier
1753 is to use the 'xkbprint' utility, if it's available on your system:
1755 xkbprint 0:0 /tmp/k.ps
1757 This produces a PostScript file '/tmp/k.ps' with a picture of your
1758 keyboard; printing that file on a PostScript printer will show what
1759 keys can serve as Meta.
1761 The 'xkeycaps' also shows a visual representation of the current
1762 keyboard settings. It also allows to modify them.
1764 *** GNU/Linux: slow startup on Linux-based GNU systems.
1766 People using systems based on the Linux kernel sometimes report that
1767 startup takes 10 to 15 seconds longer than 'usual'.
1769 This is because Emacs looks up the host name when it starts.
1770 Normally, this takes negligible time; the extra delay is due to
1771 improper system configuration. This problem can occur for both
1772 networked and non-networked machines.
1774 Here is how to fix the configuration. It requires being root.
1776 **** Networked Case.
1778 First, make sure the files '/etc/hosts' and '/etc/host.conf' both
1779 exist. The first line in the '/etc/hosts' file should look like this
1780 (replace HOSTNAME with your host name):
1784 Also make sure that the '/etc/host.conf' files contains the following
1790 Any changes, permanent and temporary, to the host name should be
1791 indicated in the '/etc/hosts' file, since it acts a limited local
1792 database of addresses and names (e.g., some SLIP connections
1793 dynamically allocate ip addresses).
1795 **** Non-Networked Case.
1797 The solution described in the networked case applies here as well.
1798 However, if you never intend to network your machine, you can use a
1799 simpler solution: create an empty '/etc/host.conf' file. The command
1800 'touch /etc/host.conf' suffices to create the file. The '/etc/hosts'
1801 file is not necessary with this approach.
1803 *** GNU/Linux: Emacs on a tty switches the cursor to large blinking block.
1805 This was reported to happen on some GNU/Linux systems which use
1806 ncurses version 5.0, but could be relevant for other versions as well.
1807 These versions of ncurses come with a 'linux' terminfo entry, where
1808 the "cvvis" capability (termcap "vs") is defined as "\E[?25h\E[?8c"
1809 (show cursor, change size). This escape sequence switches on a
1810 blinking hardware text-mode cursor whose size is a full character
1811 cell. This blinking cannot be stopped, since a hardware cursor
1814 A work-around is to redefine the "cvvis" capability so that it
1815 enables a *software* cursor. The software cursor works by inverting
1816 the colors of the character at point, so what you see is a block
1817 cursor that doesn't blink. For this to work, you need to redefine
1818 the "cnorm" capability as well, so that it operates on the software
1819 cursor instead of the hardware cursor.
1821 To this end, run "infocmp linux > linux-term", edit the file
1822 'linux-term' to make both the "cnorm" and "cvvis" capabilities send
1823 the sequence "\E[?25h\E[?17;0;64c", and then run "tic linux-term" to
1824 produce a modified terminfo entry.
1826 Alternatively, if you want a blinking underscore as your Emacs cursor,
1827 set the 'visible-cursor' variable to nil in your ~/.emacs:
1828 (setq visible-cursor nil)
1830 Still other way is to change the "cvvis" capability to send the
1831 "\E[?25h\E[?0c" command.
1835 *** FreeBSD: Getting a Meta key on the console.
1837 By default, neither Alt nor any other key acts as a Meta key on
1838 FreeBSD, but this can be changed using kbdcontrol(1). Dump the
1839 current keymap to a file with the command
1841 $ kbdcontrol -d >emacs.kbd
1843 Edit emacs.kbd, and give the key you want to be the Meta key the
1844 definition 'meta'. For instance, if your keyboard has a "Windows"
1845 key with scan code 105, change the line for scan code 105 in emacs.kbd
1848 105 meta meta meta meta meta meta meta meta O
1850 to make the Windows key the Meta key. Load the new keymap with
1852 $ kbdcontrol -l emacs.kbd
1856 *** HP/UX : Shell mode gives the message, "`tty`: Ambiguous".
1858 christos@theory.tn.cornell.edu says:
1860 The problem is that in your .cshrc you have something that tries to
1861 execute 'tty'. If you are not running the shell on a real tty then
1862 tty will print "not a tty". Csh expects one word in some places,
1863 but tty is giving it back 3.
1865 The solution is to add a pair of quotes around `tty` to make it a single
1868 if (`tty` == "/dev/console")
1870 should be changed to:
1872 if ("`tty`" == "/dev/console")
1874 Even better, move things that set up terminal sections out of .cshrc
1877 *** HP/UX: 'Pid xxx killed due to text modification or page I/O error'.
1879 On HP/UX, you can get that error when the Emacs executable is on an NFS
1880 file system. HP/UX responds this way if it tries to swap in a page and
1881 does not get a response from the server within a timeout whose default
1882 value is just ten seconds.
1884 If this happens to you, extend the timeout period.
1886 *** HP/UX: The right Alt key works wrong on German HP keyboards (and perhaps
1887 other non-English HP keyboards too).
1889 This is because HP-UX defines the modifiers wrong in X. Here is a
1890 shell script to fix the problem; be sure that it is run after VUE
1891 configures the X server.
1893 xmodmap 2> /dev/null - << EOF
1894 keysym Alt_L = Meta_L
1895 keysym Alt_R = Meta_R
1900 keysym Mode_switch = NoSymbol
1902 keysym Meta_R = Mode_switch
1903 add mod2 = Mode_switch
1906 *** HP/UX: Emacs does not recognize the AltGr key.
1908 To fix this, set up a file ~/.dt/sessions/sessionetc with executable
1909 rights, containing this text:
1911 --------------------------------
1912 xmodmap 2> /dev/null - << EOF
1913 keysym Alt_L = Meta_L
1914 keysym Alt_R = Meta_R
1919 keysym Mode_switch = NoSymbol
1921 keysym Meta_R = Mode_switch
1922 add mod2 = Mode_switch
1924 --------------------------------
1926 *** HP/UX 11.0: Emacs makes HP/UX 11.0 crash.
1928 This is a bug in HPUX; HPUX patch PHKL_16260 is said to fix it.
1932 *** AIX: Trouble using ptys.
1934 People often install the pty devices on AIX incorrectly.
1935 Use 'smit pty' to reinstall them properly.
1937 *** AIXterm: Your Delete key sends a Backspace to the terminal.
1939 The solution is to include in your .Xdefaults the lines:
1941 *aixterm.Translations: #override <Key>BackSpace: string(0x7f)
1942 aixterm*ttyModes: erase ^?
1944 This makes your Backspace key send DEL (ASCII 127).
1946 *** AIX: If linking fails because libXbsd isn't found, check if you
1947 are compiling with the system's 'cc' and CFLAGS containing '-O5'. If
1948 so, you have hit a compiler bug. Please make sure to re-configure
1949 Emacs so that it isn't compiled with '-O5'.
1951 *** AIX 4.3.x or 4.4: Compiling fails.
1953 This could happen if you use /bin/c89 as your compiler, instead of
1954 the default 'cc'. /bin/c89 treats certain warnings, such as benign
1955 redefinitions of macros, as errors, and fails the build. A solution
1956 is to use the default compiler 'cc'.
1958 *** AIX 4: Some programs fail when run in a Shell buffer
1959 with an error message like No terminfo entry for "unknown".
1961 On AIX, many terminal type definitions are not installed by default.
1962 'unknown' is one of them. Install the "Special Generic Terminal
1963 Definitions" to make them defined.
1967 We list bugs in current versions here. See also the section on legacy
1970 *** On Solaris, C-x doesn't get through to Emacs when you use the console.
1972 This is a Solaris feature (at least on Intel x86 cpus). Type C-r
1973 C-r C-t, to toggle whether C-x gets through to Emacs.
1975 *** Problem with remote X server on Suns.
1977 On a Sun, running Emacs on one machine with the X server on another
1978 may not work if you have used the unshared system libraries. This
1979 is because the unshared libraries fail to use YP for host name lookup.
1980 As a result, the host name you specify may not be recognized.
1982 *** Solaris 2.6: Emacs crashes with SIGBUS or SIGSEGV on Solaris after you delete a frame.
1984 We suspect that this is a bug in the X libraries provided by
1985 Sun. There is a report that one of these patches fixes the bug and
1986 makes the problem stop:
1988 105216-01 105393-01 105518-01 105621-01 105665-01 105615-02 105216-02
1989 105667-01 105401-08 105615-03 105621-02 105686-02 105736-01 105755-03
1990 106033-01 105379-01 105786-01 105181-04 105379-03 105786-04 105845-01
1991 105284-05 105669-02 105837-01 105837-02 105558-01 106125-02 105407-01
1993 Another person using a newer system (kernel patch level Generic_105181-06)
1994 suspects that the bug was fixed by one of these more recent patches:
1996 106040-07 SunOS 5.6: X Input & Output Method patch
1997 106222-01 OpenWindows 3.6: filemgr (ff.core) fixes
1998 105284-12 Motif 1.2.7: sparc Runtime library patch
2000 *** Solaris 7 or 8: Emacs reports a BadAtom error (from X)
2002 This happens when Emacs was built on some other version of Solaris.
2003 Rebuild it on Solaris 8.
2005 *** When using M-x dbx with the SparcWorks debugger, the 'up' and 'down'
2006 commands do not move the arrow in Emacs.
2008 You can fix this by adding the following line to '~/.dbxinit':
2010 dbxenv output_short_file_name off
2012 *** On Solaris, CTRL-t is ignored by Emacs when you use
2013 the fr.ISO-8859-15 locale (and maybe other related locales).
2015 You can fix this by editing the file:
2017 /usr/openwin/lib/locale/iso8859-15/Compose
2019 Near the bottom there is a line that reads:
2021 Ctrl<t> <quotedbl> <Y> : "\276" threequarters
2023 while it should read:
2025 Ctrl<T> <quotedbl> <Y> : "\276" threequarters
2027 Note the lower case <t>. Changing this line should make C-t work.
2029 *** On Solaris, Emacs fails to set menu-bar-update-hook on startup, with error
2030 "Error in menu-bar-update-hook: (error Point before start of properties)".
2031 This seems to be a GCC optimization bug that occurs for GCC 4.1.2 (-g
2032 and -g -O2) and GCC 4.2.3 (-g -O and -g -O2). You can fix this by
2033 compiling with GCC 4.2.3 or CC 5.7, with no optimizations.
2037 *** Irix: Trouble using ptys, or running out of ptys.
2039 The program mkpts (which may be in '/usr/adm' or '/usr/sbin') needs to
2040 be set-UID to root, or non-root programs like Emacs will not be able
2041 to allocate ptys reliably.
2043 * Runtime problems specific to MS-Windows
2045 ** Emacs on Windows 9X requires UNICOWS.DLL
2047 If that DLL is not available, Emacs will display an error dialog
2048 stating its absence, and refuse to run.
2050 This is because Emacs 24.4 and later uses functions whose non-stub
2051 implementation is only available in UNICOWS.DLL, which implements the
2052 Microsoft Layer for Unicode on Windows 9X, or "MSLU". This article on
2055 http://msdn.microsoft.com/en-us/goglobal/bb688166.aspx
2057 includes a short description of MSLU and a link where it can be
2060 ** Emacs refuses to start on Windows 9X because ctime64 function is missing
2062 This is a sign that Emacs was compiled with MinGW runtime version
2063 4.0.x or later. These versions of runtime call in their startup code
2064 the ctime64 function, which does not exist in MSVCRT.DLL, the C
2065 runtime shared library, distributed with Windows 9X.
2067 A workaround is to build Emacs with MinGW runtime 3.x (the latest
2070 ** addpm fails to run on Windows NT4, complaining about Shell32.dll
2072 This is likely to happen because Shell32.dll shipped with NT4 lacks
2073 the updates required by Emacs. Installing Internet Explorer 4 solves
2074 the problem. Note that it is NOT enough to install IE6, because doing
2075 so will not install the Shell32.dll update.
2077 ** A few seconds delay is seen at startup and for many file operations
2079 This happens when the Net Logon service is enabled. During Emacs
2080 startup, this service issues many DNS requests looking up for the
2081 Windows Domain Controller. When Emacs accesses files on networked
2082 drives, it automatically logs on the user into those drives, which
2083 again causes delays when Net Logon is running.
2085 The solution seems to be to disable Net Logon with this command typed
2086 at the Windows shell prompt:
2090 To start the service again, type "net start netlogon". (You can also
2091 stop and start the service from the Computer Management application,
2092 accessible by right-clicking "My Computer" or "Computer", selecting
2093 "Manage", then clicking on "Services".)
2095 ** Emacs crashes when exiting the Emacs session
2097 This was reported to happen when some optional DLLs, such as those
2098 used for displaying images or the GnuTLS library or zlib compression
2099 library, which are loaded on-demand, have a runtime dependency on the
2100 libgcc DLL, libgcc_s_dw2-1.dll. The reason seems to be a bug in
2101 libgcc which rears its ugly head whenever the libgcc DLL is loaded
2102 after Emacs has started.
2104 One solution for this problem is to find an alternative build of the
2105 same optional library that does not depend on the libgcc DLL.
2107 Another possibility is to rebuild Emacs with the -shared-libgcc
2108 switch, which will force Emacs to load libgcc_s_dw2-1.dll on startup,
2109 ahead of any optional DLLs loaded on-demand later in the session.
2111 ** File selection dialog opens in incorrect directories
2113 Invoking the file selection dialog on Windows 7 or later shows a
2114 directory that is different from what was passed to 'read-file-name'
2115 or 'x-file-dialog' via their arguments.
2117 This is due to a deliberate change in behavior of the file selection
2118 dialogs introduced in Windows 7. It is explicitly described in the
2119 MSDN documentation of the GetOpenFileName API used by Emacs to pop up
2120 the file selection dialog. For the details, see
2122 http://msdn.microsoft.com/en-us/library/windows/desktop/ms646839%28v=vs.85%29.aspx
2124 The dialog shows the last directory in which the user selected a file
2125 in a previous invocation of the dialog with the same initial
2128 You can reset this "memory" of that directory by invoking the file
2129 selection dialog with a different initial directory.
2131 ** PATH can contain unexpanded environment variables
2133 Old releases of TCC (version 9) and 4NT (up to version 8) do not correctly
2134 expand App Paths entries of type REG_EXPAND_SZ. When Emacs is run from TCC
2135 and such an entry exists for emacs.exe, exec-path will contain the
2136 unexpanded entry. This has been fixed in TCC 10. For more information,
2139 ** Setting w32-pass-rwindow-to-system and w32-pass-lwindow-to-system to nil
2140 does not prevent the Start menu from popping up when the left or right
2141 "Windows" key is pressed.
2143 This was reported to happen when XKeymacs is installed. At least with
2144 XKeymacs Version 3.47, deactivating XKeymacs when Emacs is active is
2145 not enough to avoid its messing with the keyboard input. Exiting
2146 XKeymacs completely is reported to solve the problem.
2148 ** Pasting from Windows clipboard into Emacs doesn't work.
2150 This was reported to be the result of an anti-virus software blocking
2151 the clipboard-related operations when a Web browser is open, for
2152 security reasons. The solution is to close the Web browser while
2153 working in Emacs, or to add emacs.exe to the list of applications that
2154 are allowed to use the clipboard when the Web browser is open.
2156 ** "Pinning" Emacs to the taskbar doesn't work on Windows 10
2158 "Doesn't work" here means that if you invoke Emacs by clicking on the
2159 pinned icon, a separate button appears on the taskbar, instead of the
2160 expected effect of the icon you clicked on being converted to that
2163 This is due to a bug in early versions of Windows 10, reportedly fixed
2164 in build 1511 of Windows 10 (a.k.a. "Windows 10 SP1"). If you cannot
2165 upgrade, read the work-around described below.
2167 First, be sure to edit the Properties of the pinned icon to invoke
2168 runemacs.exe, not emacs.exe. (The latter will cause an extra cmd
2169 window to appear when you invoke Emacs from the pinned icon.)
2171 But the real cause of the problem is the fact that the pinned icon
2172 (which is really a shortcut in a special directory) lacks a unique
2173 application-defined Application User Model ID (AppUserModelID) that
2174 identifies the current process to the taskbar. This identifier allows
2175 an application to group its associated processes and windows under a
2176 single taskbar button. Emacs on Windows specifies a unique
2177 AppUserModelID when it starts, but Windows 10, unlike previous
2178 versions of MS-Windows, does not propagate that ID to the pinned icon.
2180 To work around this, use some utility, such as 'win7appid', to set the
2181 AppUserModelID of the pinned icon to the string "Gnu.Emacs". The
2182 shortcut files corresponding to icons you pinned are stored by Windows
2183 in the following subdirectory of your user's directory (by default
2184 C:\Users\<UserName>\):
2186 AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\TaskBar
2188 Look for the file 'emacs.lnk' there.
2190 ** Windows 95 and networking.
2192 To support server sockets, Emacs loads ws2_32.dll. If this file is
2193 missing, all Emacs networking features are disabled.
2195 Old versions of Windows 95 may not have the required DLL. To use
2196 Emacs's networking features on Windows 95, you must install the
2197 "Windows Socket 2" update available from MicroSoft's support Web.
2199 ** Emacs exits with "X protocol error" when run with an X server for MS-Windows.
2201 A certain X server for Windows had a bug which caused this.
2202 Supposedly the newer 32-bit version of this server doesn't have the
2205 ** Emacs crashes when opening a file with a UNC path and rails-mode is loaded.
2207 Loading rails-mode seems to interfere with UNC path handling. This has been
2208 reported as a bug against both Emacs and rails-mode, so look for an updated
2209 rails-mode that avoids this crash, or avoid using UNC paths if using
2212 ** M-x term does not work on MS-Windows.
2214 TTY emulation on Windows is undocumented, and programs such as stty
2215 which are used on POSIX platforms to control tty emulation do not
2216 exist for native windows terminals.
2218 ** Using create-fontset-from-ascii-font or the --font startup parameter
2219 with a Chinese, Japanese or Korean font leads to display problems.
2220 Use a Latin-only font as your default font. If you want control over
2221 which font is used to display Chinese, Japanese or Korean character,
2222 use create-fontset-from-fontset-spec to define a fontset.
2224 ** Frames are not refreshed while dialogs or menus are displayed
2226 This means no redisplay while the File or Font dialog or a pop-up menu
2227 is displayed. This also means tooltips with help text for pop-up
2228 menus are not displayed at all (except in a TTY session, where the help
2229 text is shown in the echo area). This is because message handling
2230 under Windows is synchronous, so we cannot handle repaint (or any
2231 other) messages while waiting for a system function, which popped up
2232 the menu/dialog, to return the result of the dialog or pop-up menu
2235 ** Help text in tooltips does not work on old Windows versions
2237 Windows 95 and Windows NT up to version 4.0 do not support help text
2238 for menus. Help text is only available in later versions of Windows.
2240 ** Display problems with ClearType method of smoothing
2242 When "ClearType" method is selected as the "method to smooth edges of
2243 screen fonts" (in Display Properties, Appearance tab, under
2244 "Effects"), there are various problems related to display of
2245 characters: Bold fonts can be hard to read, small portions of some
2246 characters could appear chopped, etc. This happens because, under
2247 ClearType, characters are drawn outside their advertised bounding box.
2248 Emacs 21 disabled the use of ClearType, whereas Emacs 22 allows it and
2249 has some code to enlarge the width of the bounding box. Apparently,
2250 this display feature needs more changes to get it 100% right. A
2251 workaround is to disable ClearType.
2253 ** Cursor is displayed as a thin vertical bar and cannot be changed
2255 This is known to happen if the Windows Magnifier is turned on before
2256 the Emacs session starts. The Magnifier affects the cursor shape and
2257 prevents any changes to it by setting the 'cursor-type' variable or
2260 The solution is to log off and on again, and then start the Emacs
2261 session only after turning the Magnifier off.
2263 To turn the Windows Magnifier off, click "Start->All Programs", or
2264 "All Apps", depending on your Windows version, then select
2265 "Accessibility" and click "Magnifier". In the Magnifier Settings
2266 dialog that opens, click "Exit".
2268 ** Problems with mouse-tracking and focus management
2270 There are problems with display if mouse-tracking is enabled and the
2271 mouse is moved off a frame, over another frame then back over the first
2272 frame. A workaround is to click the left mouse button inside the frame
2273 after moving back into it.
2275 Some minor flickering still persists during mouse-tracking, although
2276 not as severely as in 21.1.
2278 An inactive cursor remains in an active window after the Windows
2279 Manager driven switch of the focus, until a key is pressed.
2281 ** Problems with Windows input methods
2283 Some of the Windows input methods cause the keyboard to send
2284 characters encoded in the appropriate coding system (e.g., ISO 8859-1
2285 for Latin-1 characters, ISO 8859-8 for Hebrew characters, etc.). To
2286 make these input methods work with Emacs on Windows 9X, you might need
2287 to set the keyboard coding system to the appropriate value after you
2288 activate the Windows input method. For example, if you activate the
2289 Hebrew input method, type this:
2291 C-x RET k hebrew-iso-8bit RET
2293 In addition, to use these Windows input methods, you might need to set
2294 your "Language for non-Unicode programs" (on Windows XP, this is on
2295 the Advanced tab of Regional Settings) to the language of the input
2298 To bind keys that produce non-ASCII characters with modifiers, you
2299 must specify raw byte codes. For instance, if you want to bind
2300 META-a-grave to a command, you need to specify this in your '~/.emacs':
2302 (global-set-key [?\M-\340] ...)
2304 The above example is for the Latin-1 environment where the byte code
2305 of the encoded a-grave is 340 octal. For other environments, use the
2306 encoding appropriate to that environment.
2308 ** Problems with the %b format specifier for format-time-string
2310 The %b specifier for format-time-string does not produce abbreviated
2311 month names with consistent widths for some locales on some versions
2312 of Windows. This is caused by a deficiency in the underlying system
2315 ** Non-US time zones.
2317 Many non-US time zones are implemented incorrectly. This is due to
2318 over-simplistic handling of daylight savings switchovers by the
2321 ** Files larger than 4GB report wrong size in a 32-bit Windows build
2323 Files larger than 4GB cause overflow in the size (represented as a
2324 32-bit integer) reported by 'file-attributes'. This affects Dired as
2325 well, since the Windows port uses a Lisp emulation of 'ls', which relies
2326 on 'file-attributes'.
2328 ** Playing sound doesn't support the :data method
2330 Sound playing is not supported with the ':data DATA' key-value pair.
2331 You _must_ use the ':file FILE' method.
2333 ** Typing Alt-Shift has strange effects on MS-Windows.
2335 This combination of keys is a command to change keyboard layout. If
2336 you proceed to type another non-modifier key before you let go of Alt
2337 and Shift, the Alt and Shift act as modifiers in the usual way. A
2338 more permanent work around is to change it to another key combination,
2339 or disable it in the "Regional and Language Options" applet of the
2340 Control Panel. (The exact sequence of mouse clicks in the "Regional
2341 and Language Options" applet needed to find the key combination that
2342 changes the keyboard layout depends on your Windows version; for XP,
2343 in the Languages tab, click "Details" and then "Key Settings".)
2345 ** Interrupting Cygwin port of Bash from Emacs doesn't work.
2347 Cygwin 1.x builds of the ported Bash cannot be interrupted from the
2348 MS-Windows version of Emacs. This is due to some change in the Bash
2349 port or in the Cygwin library which apparently make Bash ignore the
2350 keyboard interrupt event sent by Emacs to Bash. (Older Cygwin ports
2351 of Bash, up to b20.1, did receive SIGINT from Emacs.)
2353 ** Accessing remote files with ange-ftp hangs the MS-Windows version of Emacs.
2355 If the FTP client is the Cygwin port of GNU 'ftp', this appears to be
2356 due to some bug in the Cygwin DLL or some incompatibility between it
2357 and the implementation of asynchronous subprocesses in the Windows
2358 port of Emacs. Specifically, some parts of the FTP server responses
2359 are not flushed out, apparently due to buffering issues, which
2362 The solution is to downgrade to an older version of the Cygwin DLL
2363 (version 1.3.2 was reported to solve the problem), or use the stock
2364 Windows FTP client, usually found in the 'C:\WINDOWS' or 'C:\WINNT'
2365 directory. To force ange-ftp use the stock Windows client, set the
2366 variable 'ange-ftp-ftp-program-name' to the absolute file name of the
2367 client's executable. For example:
2369 (setq ange-ftp-ftp-program-name "c:/windows/ftp.exe")
2371 If you want to stick with the Cygwin FTP client, you can work around
2372 this problem by putting this in your '.emacs' file:
2374 (setq ange-ftp-ftp-program-args '("-i" "-n" "-g" "-v" "--prompt" "")
2376 ** lpr commands don't work on MS-Windows with some cheap printers.
2378 This problem may also strike other platforms, but the solution is
2379 likely to be a global one, and not Emacs specific.
2381 Many cheap inkjet, and even some cheap laser printers, do not
2382 print plain text anymore, they will only print through graphical
2383 printer drivers. A workaround on MS-Windows is to use Windows's basic
2384 built in editor to print (this is possibly the only useful purpose it
2387 (setq printer-name "") ; notepad takes the default
2388 (setq lpr-command "notepad") ; notepad
2389 (setq lpr-switches nil) ; not needed
2390 (setq lpr-printer-switch "/P") ; run notepad as batch printer
2392 ** Antivirus software interacts badly with the MS-Windows version of Emacs.
2394 The usual manifestation of these problems is that subprocesses don't
2395 work or even wedge the entire system. In particular, "M-x shell RET"
2396 was reported to fail to work. But other commands also sometimes don't
2397 work when an antivirus package is installed.
2399 The solution is to switch the antivirus software to a less aggressive
2400 mode (e.g., disable the "auto-protect" feature), or even uninstall
2401 or disable it entirely.
2403 ** Pressing the mouse button on MS-Windows does not give a mouse-2 event.
2405 This is usually a problem with the mouse driver. Because most Windows
2406 programs do not do anything useful with the middle mouse button, many
2407 mouse drivers allow you to define the wheel press to do something
2408 different. Some drivers do not even have the option to generate a
2409 middle button press. In such cases, setting the wheel press to
2410 "scroll" sometimes works if you press the button twice. Trying a
2411 generic mouse driver might help.
2413 ** Scrolling the mouse wheel on MS-Windows always scrolls the top window.
2415 This is another common problem with mouse drivers. Instead of
2416 generating scroll events, some mouse drivers try to fake scroll bar
2417 movement. But they are not intelligent enough to handle multiple
2418 scroll bars within a frame. Trying a generic mouse driver might help.
2420 ** Mail sent through Microsoft Exchange in some encodings appears to be
2421 mangled and is not seen correctly in Rmail or Gnus. We don't know
2422 exactly what happens, but it isn't an Emacs problem in cases we've
2425 ** On MS-Windows, you cannot use the right-hand ALT key and the left-hand
2426 CTRL key together to type a Control-Meta character.
2428 This is a consequence of a misfeature beyond Emacs's control.
2430 Under Windows, the AltGr key on international keyboards generates key
2431 events with the modifiers Right-Alt and Left-Ctrl. Since Emacs cannot
2432 distinguish AltGr from an explicit Right-Alt and Left-Ctrl
2433 combination, whenever it sees Right-Alt and Left-Ctrl it assumes that
2434 AltGr has been pressed. The variable 'w32-recognize-altgr' can be set
2435 to nil to tell Emacs that AltGr is really Ctrl and Alt.
2437 ** Under some X-servers running on MS-Windows, Emacs's display is incorrect.
2439 The symptoms are that Emacs does not completely erase blank areas of the
2440 screen during scrolling or some other screen operations (e.g., selective
2441 display or when killing a region). M-x recenter will cause the screen
2442 to be completely redisplayed and the "extra" characters will disappear.
2444 This is known to occur under Exceed 6, and possibly earlier versions
2445 as well; it is reportedly solved in version 6.2.0.16 and later. The
2446 problem lies in the X-server settings.
2448 There are reports that you can solve the problem with Exceed by
2449 running 'Xconfig' from within NT, choosing "X selection", then
2450 un-checking the boxes "auto-copy X selection" and "auto-paste to X
2453 If this does not work, please inform bug-gnu-emacs@gnu.org. Then
2454 please call support for your X-server and see if you can get a fix.
2455 If you do, please send it to bug-gnu-emacs@gnu.org so we can list it here.
2457 * Build-time problems
2461 *** 'configure' warns "accepted by the compiler, rejected by the preprocessor".
2463 This indicates a mismatch between the C compiler and preprocessor that
2464 configure is using. For example, on Solaris 10 trying to use
2465 CC=/opt/SUNWspro/bin/cc (the Sun Studio compiler) together with
2466 CPP=/usr/ccs/lib/cpp can result in errors of this form (you may also
2467 see the error '"/usr/include/sys/isa_defs.h", line 500: undefined control').
2469 The solution is to tell configure to use the correct C preprocessor
2470 for your C compiler (CPP="/opt/SUNWspro/bin/cc -E" in the above
2475 *** Building Emacs over NFS fails with "Text file busy".
2477 This was reported to happen when building Emacs on a GNU/Linux system
2478 (Red Hat Linux 6.2) using a build directory automounted from Solaris
2479 (SunOS 5.6) file server, but it might not be limited to that
2480 configuration alone. Presumably, the NFS server doesn't commit the
2481 files' data to disk quickly enough, and the Emacs executable file is
2482 left "busy" for several seconds after Emacs has finished dumping
2483 itself. This causes the subsequent commands which invoke the dumped
2484 Emacs executable to fail with the above message.
2486 In some of these cases, a time skew between the NFS server and the
2487 machine where Emacs is built is detected and reported by GNU Make
2488 (it says that some of the files have modification time in the future).
2489 This might be a symptom of NFS-related problems.
2491 If the NFS server runs on Solaris, apply the Solaris patch 105379-05
2492 (Sunos 5.6: /kernel/misc/nfssrv patch). If that doesn't work, or if
2493 you have a different version of the OS or the NFS server, you can
2494 force the NFS server to use 1KB blocks, which was reported to fix the
2495 problem albeit at a price of slowing down file I/O. You can force 1KB
2496 blocks by specifying the "-o rsize=1024,wsize=1024" options to the
2497 'mount' command, or by adding ",rsize=1024,wsize=1024" to the mount
2498 options in the appropriate system configuration file, such as
2501 Alternatively, when Make fails due to this problem, you could wait for
2502 a few seconds and then invoke Make again. In one particular case,
2503 waiting for 10 or more seconds between the two Make invocations seemed
2504 to work around the problem.
2506 Similar problems can happen if your machine NFS-mounts a directory
2507 onto itself. Suppose the Emacs sources live in '/usr/local/src' and
2508 you are working on the host called 'marvin'. Then an entry in the
2509 '/etc/fstab' file like the following is asking for trouble:
2511 marvin:/usr/local/src /usr/local/src ...options.omitted...
2513 The solution is to remove this line from '/etc/fstab'.
2515 *** Building a 32-bit executable on a 64-bit GNU/Linux architecture.
2517 First ensure that the necessary 32-bit system libraries and include
2518 files are installed. Then use:
2520 env CC="gcc -m32" ./configure --build=i386-linux-gnu --x-libraries=/usr/lib
2522 (using the location of the 32-bit X libraries on your system).
2524 *** Building on FreeBSD 11 fails at link time due to unresolved symbol
2526 The symbol is sendmmsg@FBSD_1.4. This is due to a faulty libgio
2527 library on these systems. The solution is to reconfigure Emacs while
2528 disabling all the features that require libgio: rsvg, dbus, gconf, and
2531 *** Building Emacs for Cygwin can fail with GCC 3
2533 As of Emacs 22.1, there have been stability problems with Cygwin
2534 builds of Emacs using GCC 3. Cygwin users are advised to use GCC 4.
2536 *** Building Emacs 23.3 and later will fail under Cygwin 1.5.19
2538 This is a consequence of a change to src/dired.c on 2010-07-27. The
2539 issue is that Cygwin 1.5.19 did not have d_ino in 'struct dirent'.
2542 http://lists.gnu.org/archive/html/emacs-devel/2010-07/msg01266.html
2544 *** Building the native MS-Windows port fails due to unresolved externals
2546 The linker error messages look like this:
2548 oo-spd/i386/ctags.o:ctags.c:(.text+0x156e): undefined reference to `_imp__re_set_syntax'
2549 collect2: ld returned 1 exit status
2551 This happens because GCC finds an incompatible regex.h header
2552 somewhere on the include path, before the version of regex.h supplied
2553 with Emacs. One such incompatible version of regex.h is part of the
2554 GnuWin32 Regex package.
2556 The solution is to remove the incompatible regex.h from the include
2557 path, when compiling Emacs. Alternatively, re-run the configure.bat
2558 script with the "-isystem C:/GnuWin32/include" switch (adapt for your
2559 system's place where you keep the GnuWin32 include files) -- this will
2560 cause the compiler to search headers in the directories specified by
2561 the Emacs Makefile _before_ it looks in the GnuWin32 include
2564 *** Building the native MS-Windows port with Cygwin GCC can fail.
2566 Emacs may not build using some Cygwin builds of GCC, such as Cygwin
2567 version 1.1.8, using the default configure settings. It appears to be
2568 necessary to specify the -mwin32 flag when compiling, and define
2569 __MSVCRT__, like so:
2571 configure --with-gcc --cflags -mwin32 --cflags -D__MSVCRT__
2573 *** Building the MS-Windows port fails with a CreateProcess failure.
2575 Some versions of mingw32 make on some versions of Windows do not seem
2576 to detect the shell correctly. Try "make SHELL=cmd.exe", or if that
2577 fails, try running make from Cygwin bash instead.
2579 *** Building 'ctags' for MS-Windows with the MinGW port of GCC fails.
2581 This might happen due to a bug in the MinGW header assert.h, which
2582 defines the 'assert' macro with a trailing semi-colon. The following
2583 patch to assert.h should solve this:
2585 *** include/assert.h.orig Sun Nov 7 02:41:36 1999
2586 --- include/assert.h Mon Jan 29 11:49:10 2001
2590 * If not debugging, assert does nothing.
2592 ! #define assert(x) ((void)0);
2594 #else /* debugging enabled */
2598 * If not debugging, assert does nothing.
2600 ! #define assert(x) ((void)0)
2602 #else /* debugging enabled */
2605 *** Building the MS-Windows port with Visual Studio 2005 fails.
2607 Microsoft no longer ships the single threaded version of the C library
2608 with their compiler, and the multithreaded static library is missing
2609 some functions that Microsoft have deemed non-threadsafe. The
2610 dynamically linked C library has all the functions, but there is a
2611 conflict between the versions of malloc in the DLL and in Emacs, which
2612 is not resolvable due to the way Windows does dynamic linking.
2614 We recommend the use of the MinGW port of GCC for compiling Emacs, as
2615 not only does it not suffer these problems, but it is also Free
2616 software like Emacs.
2618 *** Building the MS-Windows port with Visual Studio fails compiling emacs.rc
2620 If the build fails with the following message then the problem
2621 described here most likely applies:
2623 ../nt/emacs.rc(1) : error RC2176 : old DIB in icons\emacs.ico; pass it
2626 The Emacs icon contains a high resolution PNG icon for Vista, which is
2627 not recognized by older versions of the resource compiler. There are
2628 several workarounds for this problem:
2629 1. Use Free MinGW tools to compile, which do not have this problem.
2630 2. Install the latest Windows SDK.
2631 3. Replace emacs.ico with an older or edited icon.
2633 *** Building the MS-Windows port complains about unknown escape sequences.
2635 Errors and warnings can look like this:
2637 w32.c:1959:27: error: \x used with no following hex digits
2638 w32.c:1959:27: warning: unknown escape sequence '\i'
2640 This happens when paths using backslashes are passed to the compiler or
2641 linker (via -I and possibly other compiler flags); when these paths are
2642 included in source code, the backslashes are interpreted as escape sequences.
2643 See http://lists.gnu.org/archive/html/emacs-devel/2010-07/msg00995.html
2645 The fix is to use forward slashes in all paths passed to the compiler.
2649 *** Building Emacs with a system compiler fails to link because of an
2650 undefined symbol such as __eprintf which does not appear in Emacs.
2652 This can happen if some of the libraries linked into Emacs were built
2653 with GCC, but Emacs itself is being linked with a compiler other than
2654 GCC. Object files compiled with GCC might need some helper functions
2655 from libgcc.a, the library which comes with GCC, but the system
2656 compiler does not instruct the linker to search libgcc.a during the
2659 A solution is to link with GCC, like this:
2663 Since the .o object files already exist, this will not recompile Emacs
2664 with GCC, but just restart by trying again to link temacs.
2666 *** Sun with acc: Link failure when using acc on a Sun.
2668 To use acc, you need additional options just before the libraries, such as
2670 /usr/lang/SC2.0.1/values-Xt.o -L/usr/lang/SC2.0.1/cg87 -L/usr/lang/SC2.0.1
2672 and you need to add -lansi just before -lc.
2674 The precise file names depend on the compiler version, so we
2675 cannot easily arrange to supply them.
2677 *** 'tparam' reported as a multiply-defined symbol when linking with ncurses.
2679 This problem results from an incompatible change in ncurses, in
2680 version 1.9.9e approximately. This version is unable to provide a
2681 definition of tparm without also defining tparam. This is also
2682 incompatible with Terminfo; as a result, the Emacs Terminfo support
2683 does not work with this version of ncurses.
2685 The fix is to install a newer version of ncurses, such as version 4.2.
2689 Bootstrapping (compiling the .el files) is normally only necessary
2690 with development builds, since the .elc files are pre-compiled in releases.
2692 *** "No rule to make target" with Ubuntu 8.04 make 3.81-3build1
2694 Compiling the lisp files fails at random places, complaining:
2695 "No rule to make target '/path/to/some/lisp.elc'".
2696 The causes of this problem are not understood. Using GNU make 3.81 compiled
2697 from source, rather than the Ubuntu version, worked.
2698 See <URL:http://debbugs.gnu.org/327>, <URL:http://debbugs.gnu.org/821>.
2702 *** Segfault during 'make'
2704 If Emacs segfaults when 'make' executes one of these commands:
2706 LC_ALL=C ./temacs -batch -l loadup bootstrap
2707 LC_ALL=C ./temacs -batch -l loadup dump
2709 the problem may be due to inadequate workarounds for address space
2710 layout randomization (ASLR), an operating system feature that
2711 randomizes the virtual address space of a process. ASLR is commonly
2712 enabled in Linux and NetBSD kernels, and is intended to deter exploits
2713 of pointer-related bugs in applications. If ASLR is enabled, the
2716 cat /proc/sys/kernel/randomize_va_space # GNU/Linux
2717 sysctl security.pax.aslr.global # NetBSD
2719 outputs a nonzero value.
2721 These segfaults should not occur on most modern systems, because the
2722 Emacs build procedure uses the command 'setfattr' or 'paxctl' to mark
2723 the Emacs executable as requiring non-randomized address space, and
2724 Emacs uses the 'personality' system call to disable address space
2725 randomization when dumping. However, older kernels may not support
2726 'setfattr', 'paxctl', or 'personality', and newer Linux kernels have a
2727 secure computing mode (seccomp) that can be configured to disable the
2730 It may be possible to work around the 'personality' problem in a newer
2731 Linux kernel by configuring seccomp to allow the 'personality' call.
2732 For example, if you are building Emacs under Docker, you can run the
2733 Docker container with a security profile that allows 'personality' by
2734 using Docker's --security-opt option with an appropriate profile; see
2735 <https://docs.docker.com/engine/security/seccomp/>.
2737 To work around the ASLR problem in either an older or a newer kernel,
2738 you can temporarily disable the feature while building Emacs. On
2739 GNU/Linux you can do so using the following command (as root).
2741 echo 0 > /proc/sys/kernel/randomize_va_space
2743 You can re-enable the feature when you are done, by echoing the
2744 original value back to the file. NetBSD uses a different command,
2745 e.g., 'sysctl -w security.pax.aslr.global=0'.
2747 Alternatively, you can try using the 'setarch' command when building
2748 temacs like this, where -R disables address space randomization:
2750 setarch $(uname -m) -R make
2752 ASLR is not the only problem that can break Emacs dumping. Another
2753 issue is that in Red Hat Linux kernels, Exec-shield is enabled by
2754 default, and this creates a different memory layout. Emacs should
2755 handle this at build time, but if this fails the following
2756 instructions may be useful. Exec-shield is enabled on your system if
2758 cat /proc/sys/kernel/exec-shield
2760 prints a nonzero value. You can temporarily disable it as follows:
2762 echo 0 > /proc/sys/kernel/exec-shield
2764 As with randomize_va_space, you can re-enable Exec-shield when you are
2765 done, by echoing the original value back to the file.
2767 *** temacs prints "Pure Lisp storage exhausted".
2769 This means that the Lisp code loaded from the .elc and .el files during
2770 'temacs --batch --load loadup dump' took up more space than was allocated.
2772 This could be caused by
2773 1) adding code to the preloaded Lisp files
2774 2) adding more preloaded files in loadup.el
2775 3) having a site-init.el or site-load.el which loads files.
2776 Note that ANY site-init.el or site-load.el is nonstandard;
2777 if you have received Emacs from some other site and it contains a
2778 site-init.el or site-load.el file, consider deleting that file.
2779 4) getting the wrong .el or .elc files
2780 (not from the directory you expected).
2781 5) deleting some .elc files that are supposed to exist.
2782 This would cause the source files (.el files) to be
2783 loaded instead. They take up more room, so you lose.
2784 6) a bug in the Emacs distribution which underestimates the space required.
2786 If the need for more space is legitimate, change the definition
2787 of PURESIZE in puresize.h.
2789 But in some of the cases listed above, this problem is a consequence
2790 of something else that is wrong. Be sure to check and fix the real problem.
2792 *** OpenBSD 4.0 macppc: Segfault during dumping.
2794 The build aborts with signal 11 when the command './temacs --batch
2795 --load loadup bootstrap' tries to load files.el. A workaround seems
2796 to be to reduce the level of compiler optimization used during the
2797 build (from -O2 to -O1). It is possible this is an OpenBSD
2798 GCC problem specific to the macppc architecture, possibly only
2799 occurring with older versions of GCC (e.g. 3.3.5).
2801 *** openSUSE 10.3: Segfault in bcopy during dumping.
2803 This is due to a bug in the bcopy implementation in openSUSE 10.3.
2804 It is/will be fixed in an openSUSE update.
2808 *** Emacs binary is not in executable format, and cannot be run.
2810 This was reported to happen when Emacs is built in a directory mounted
2811 via NFS, for some combinations of NFS client and NFS server.
2812 Usually, the file 'emacs' produced in these cases is full of
2813 binary null characters, and the 'file' utility says:
2815 emacs: ASCII text, with no line terminators
2817 We don't know what exactly causes this failure. A work-around is to
2818 build Emacs in a directory on a local disk.
2820 *** The dumped Emacs crashes when run, trying to write pure data.
2822 On a system where getpagesize is not a system call, it is defined
2823 as a macro. If the definition (in both unex*.c and malloc.c) is wrong,
2824 it can cause problems like this. You might be able to find the correct
2825 value in the man page for a.out(5).
2827 * Problems on legacy systems
2829 This section covers bugs reported on very old hardware or software.
2830 If you are using hardware and an operating system shipped after 2000,
2831 it is unlikely you will see any of these.
2835 **** Strange results from format %d in a few cases, on a Sun.
2837 Sun compiler version SC3.0 has been found to miscompile part of editfns.c.
2838 The workaround is to compile with some other compiler such as GCC.
2840 **** On Solaris, Emacs dumps core if lisp-complete-symbol is called.
2842 If you compile Emacs with the -fast or -xO4 option with version 3.0.2
2843 of the Sun C compiler, Emacs dumps core when lisp-complete-symbol is
2844 called. The problem does not happen if you compile with GCC.
2846 **** On Solaris, Emacs crashes if you use (display-time).
2848 This can happen if you configure Emacs without specifying the precise
2849 version of Solaris that you are using.
2851 **** Solaris 2.x: GCC complains "64 bit integer types not supported".
2853 This suggests that GCC is not installed correctly. Most likely you
2854 are using GCC 2.7.2.3 (or earlier) on Solaris 2.6 (or later); this
2855 does not work without patching. To run GCC 2.7.2.3 on Solaris 2.6 or
2856 later, you must patch fixinc.svr4 and reinstall GCC from scratch as
2857 described in the Solaris FAQ
2858 <http://www.wins.uva.nl/pub/solaris/solaris2.html>. A better fix is
2859 to upgrade to GCC 2.8.1 or later.
2861 **** Solaris 2.7: Building Emacs with WorkShop Compilers 5.0 98/12/15
2862 C 5.0 failed, apparently with non-default CFLAGS, most probably due to
2863 compiler bugs. Using Sun Solaris 2.7 Sun WorkShop 6 update 1 C
2864 release was reported to work without problems. It worked OK on
2865 another system with Solaris 8 using apparently the same 5.0 compiler
2866 and the default CFLAGS.
2868 **** Solaris 2.x: Emacs dumps core when built with Motif.
2870 The Solaris Motif libraries are buggy, at least up through Solaris 2.5.1.
2871 Install the current Motif runtime library patch appropriate for your host.
2872 (Make sure the patch is current; some older patch versions still have the bug.)
2873 You should install the other patches recommended by Sun for your host, too.
2874 You can obtain Sun patches from ftp://sunsolve.sun.com/pub/patches/;
2875 look for files with names ending in '.PatchReport' to see which patches
2876 are currently recommended for your host.
2878 On Solaris 2.6, Emacs is said to work with Motif when Solaris patch
2879 105284-12 is installed, but fail when 105284-15 is installed.
2880 105284-18 might fix it again.
2882 **** Solaris 2.6 and 7: the Compose key does not work.
2884 This is a bug in Motif in Solaris. Supposedly it has been fixed for
2885 the next major release of Solaris. However, if someone with Sun
2886 support complains to Sun about the bug, they may release a patch.
2887 If you do this, mention Sun bug #4188711.
2889 One workaround is to use a locale that allows non-ASCII characters.
2890 For example, before invoking emacs, set the LC_ALL environment
2891 variable to "en_US" (American English). The directory /usr/lib/locale
2892 lists the supported locales; any locale other than "C" or "POSIX"
2895 pen@lysator.liu.se says (Feb 1998) that the Compose key does work
2896 if you link with the MIT X11 libraries instead of the Solaris X11 libraries.
2898 ** MS-Windows 95, 98, ME, and NT
2900 *** MS-Windows NT/95: Problems running Perl under Emacs
2902 'perl -de 0' just hangs when executed in an Emacs subshell.
2903 The fault lies with Perl (indirectly with Windows NT/95).
2905 The problem is that the Perl debugger explicitly opens a connection to
2906 "CON", which is the DOS/NT equivalent of "/dev/tty", for interacting
2909 On Unix, this is okay, because Emacs (or the shell?) creates a
2910 pseudo-tty so that /dev/tty is really the pipe Emacs is using to
2911 communicate with the subprocess.
2913 On NT, this fails because CON always refers to the handle for the
2914 relevant console (approximately equivalent to a tty), and cannot be
2915 redirected to refer to the pipe Emacs assigned to the subprocess as
2918 A workaround is to modify perldb.pl to use STDIN/STDOUT instead of CON.
2922 *** PERL/LIB/PERLDB.PL.orig Wed May 26 08:24:18 1993
2923 --- PERL/LIB/PERLDB.PL Mon Jul 01 15:28:16 1996
2930 $rcfile="perldb.ini";
2938 $rcfile="perldb.ini";
2943 *** perl/5.001/lib/perl5db.pl.orig Sun Jun 04 21:13:40 1995
2944 --- perl/5.001/lib/perl5db.pl Mon Jul 01 17:00:08 1996
2951 $rcfile="perldb.ini";
2959 $rcfile="perldb.ini";
2963 *** MS-Windows 95: Alt-f6 does not get through to Emacs.
2965 This character seems to be trapped by the kernel in Windows 95.
2966 You can enter M-f6 by typing ESC f6.
2968 *** MS-Windows 95/98/ME: subprocesses do not terminate properly.
2970 This is a limitation of the Operating System, and can cause problems
2971 when shutting down Windows. Ensure that all subprocesses are exited
2972 cleanly before exiting Emacs. For more details, see the Emacs on MS
2973 Windows FAQ (info manual "efaq-w32").
2975 *** MS-Windows 95/98/ME: crashes when Emacs invokes non-existent programs.
2977 When a program you are trying to run is not found on the PATH,
2978 Windows might respond by crashing or locking up your system. In
2979 particular, this has been reported when trying to compile a Java
2980 program in JDEE when javac.exe is installed, but not on the system PATH.
2984 *** When compiling with DJGPP on MS-Windows NT or later, "config msdos" fails.
2986 If the error message is "VDM has been already loaded", this is because
2987 Windows has a program called 'redir.exe' that is incompatible with a
2988 program by the same name supplied with DJGPP, which is used by
2989 config.bat. To resolve this, move the DJGPP's 'bin' subdirectory to
2990 the front of your PATH environment variable.
2992 *** When Emacs compiled with DJGPP runs on Windows 2000 and later, it cannot
2993 find your HOME directory.
2995 This was reported to happen when you click on "Save for future
2996 sessions" button in a Customize buffer. You might see an error
2997 message like this one:
2999 basic-save-buffer-2: c:/FOO/BAR/~dosuser/: no such directory
3001 (The telltale sign is the "~USER" part at the end of the directory
3002 Emacs complains about, where USER is your username or the literal
3003 string "dosuser", which is the default username set up by the DJGPP
3004 startup file DJGPP.ENV.)
3006 This happens when the functions 'user-login-name' and
3007 'user-real-login-name' return different strings for your username as
3008 Emacs sees it. To correct this, make sure both USER and USERNAME
3009 environment variables are set to the same value. Windows 2000 and
3010 later sets USERNAME, so if you want to keep that, make sure USER is
3011 set to the same value. If you don't want to set USER globally, you
3012 can do it in the [emacs] section of your DJGPP.ENV file.
3014 *** When Emacs compiled with DJGPP runs on Vista, it runs out of memory.
3016 If Emacs running on Vista displays "!MEM FULL!" in the mode line, you
3017 are hitting the memory allocation bugs in the Vista DPMI server. See
3018 msdos/INSTALL for how to work around these bugs (search for "Vista").
3020 *** When compiling with DJGPP on MS-Windows 95, Make fails for some targets
3023 This can happen if long file name support (the setting of environment
3024 variable LFN) when Emacs distribution was unpacked and during
3025 compilation are not the same. See msdos/INSTALL for the explanation
3026 of how to avoid this problem.
3028 *** Emacs compiled with DJGPP complains at startup:
3030 "Wrong type of argument: internal-facep, msdos-menu-active-face"
3032 This can happen if you define an environment variable 'TERM'. Emacs
3033 on MSDOS uses an internal terminal emulator which is disabled if the
3034 value of 'TERM' is anything but the string "internal". Emacs then
3035 works as if its terminal were a dumb glass teletype that doesn't
3036 support faces. To work around this, arrange for 'TERM' to be
3037 undefined when Emacs runs. The best way to do that is to add an
3038 [emacs] section to the DJGPP.ENV file which defines an empty value for
3039 'TERM'; this way, only Emacs gets the empty value, while the rest of
3040 your system works as before.
3042 *** MS-DOS: Emacs crashes at startup.
3044 Some users report that Emacs 19.29 requires dpmi memory management,
3045 and crashes on startup if the system does not have it. We don't
3046 know why this happens--perhaps these machines don't have enough real
3047 memory, or perhaps something is wrong in Emacs or the compiler.
3048 However, arranging to use dpmi support is a workaround.
3050 You can find out if you have a dpmi host by running go32 without
3051 arguments; it will tell you if it uses dpmi memory. For more
3052 information about dpmi memory, consult the djgpp FAQ. (djgpp
3053 is the GNU C compiler as packaged for MSDOS.)
3055 Compiling Emacs under MSDOS is extremely sensitive for proper memory
3056 configuration. If you experience problems during compilation, consider
3057 removing some or all memory resident programs (notably disk caches)
3058 and make sure that your memory managers are properly configured. See
3059 the djgpp faq for configuration hints.
3061 *** Emacs compiled with DJGPP for MS-DOS/MS-Windows cannot access files
3062 in the directory with the special name 'dev' under the root of any
3063 drive, e.g. 'c:/dev'.
3065 This is an unfortunate side-effect of the support for Unix-style
3066 device names such as /dev/null in the DJGPP runtime library. A
3067 work-around is to rename the problem directory to another name.
3069 *** MS-DOS: Emacs compiled for MSDOS cannot find some Lisp files, or other
3070 run-time support files, when long filename support is enabled.
3072 Usually, this problem will manifest itself when Emacs exits
3073 immediately after flashing the startup screen, because it cannot find
3074 the Lisp files it needs to load at startup. Redirect Emacs stdout
3075 and stderr to a file to see the error message printed by Emacs.
3077 Another manifestation of this problem is that Emacs is unable to load
3078 the support for editing program sources in languages such as C and Lisp.
3080 This can happen if the Emacs distribution was unzipped without LFN
3081 support, thus causing long filenames to be truncated to the first 6
3082 characters and a numeric tail that Windows 95 normally attaches to it.
3083 You should unzip the files again with a utility that supports long
3084 filenames (such as djtar from DJGPP or InfoZip's UnZip program
3085 compiled with DJGPP v2). The file msdos/INSTALL explains this issue
3088 Another possible reason for such failures is that Emacs compiled for
3089 MSDOS is used on Windows NT, where long file names are not supported
3090 by this version of Emacs, but the distribution was unpacked by an
3091 unzip program that preserved the long file names instead of truncating
3092 them to DOS 8+3 limits. To be useful on NT, the MSDOS port of Emacs
3093 must be unzipped by a DOS utility, so that long file names are
3096 ** Archaic window managers and toolkits
3098 *** Open Look: Under Open Look, the Emacs window disappears when you type M-q.
3100 Some versions of the Open Look window manager interpret M-q as a quit
3101 command for whatever window you are typing at. If you want to use
3102 Emacs with that window manager, you should try to configure the window
3103 manager to use some other command. You can disable the
3104 shortcut keys entirely by adding this line to ~/.OWdefaults:
3106 OpenWindows.WindowMenuAccelerators: False
3108 *** twm: A position you specified in .Xdefaults is ignored, using twm.
3110 twm normally ignores "program-specified" positions.
3111 You can tell it to obey them with this command in your '.twmrc' file:
3113 UsePPosition "on" #allow clients to request a position
3115 ** Bugs related to old DEC hardware
3117 *** The Compose key on a DEC keyboard does not work as Meta key.
3119 This shell command should fix it:
3121 xmodmap -e 'keycode 0xb1 = Meta_L'
3123 *** Keyboard input gets confused after a beep when using a DECserver
3126 This problem seems to be a matter of configuring the DECserver to use
3127 7 bit characters rather than 8 bit characters.
3129 This file is part of GNU Emacs.
3131 GNU Emacs is free software: you can redistribute it and/or modify
3132 it under the terms of the GNU General Public License as published by
3133 the Free Software Foundation, either version 3 of the License, or
3134 (at your option) any later version.
3136 GNU Emacs is distributed in the hope that it will be useful,
3137 but WITHOUT ANY WARRANTY; without even the implied warranty of
3138 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
3139 GNU General Public License for more details.
3141 You should have received a copy of the GNU General Public License
3142 along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
3147 paragraph-separate: "[
\f]*$"