1Known Problems with GNU Emacs 2 3Copyright (C) 1987-1989, 1993-1999, 2001-2021 Free Software Foundation, 4Inc. 5See the end of the file for license conditions. 6 7 8This file describes various problems that have been encountered 9in compiling, installing and running GNU Emacs. Try doing C-c C-t 10and browsing through the outline headers. (See C-h m for help on 11Outline mode.) Information about systems that are no longer supported, 12and old Emacs releases, has been removed. Consult older versions of 13this file if you are interested in that information. 14 15* Mule-UCS doesn't work in Emacs 23 onwards 16 17It's completely redundant now, as far as we know. 18 19* Emacs startup failures 20 21** Emacs fails to start, complaining about missing fonts. 22 23A typical error message might be something like 24 25 No fonts match ‘-*-fixed-medium-r-*--6-*-*-*-*-*-iso8859-1’ 26 27This happens because some X resource specifies a bad font family for 28Emacs to use. The possible places where this specification might be are: 29 30 - in the X server resources database, often initialized from 31 ~/.Xresources (use $ xrdb -query to find out the current state) 32 33 - in your ~/.Xdefaults file 34 35 - client-side X resource file, such as ~/Emacs or 36 /usr/share/X11/app-defaults/Emacs 37 38One of these files might have bad or malformed specification of a 39fontset that Emacs should use. To fix the problem, you need to find 40the problematic line(s) and correct them. 41 42After correcting ~/.Xresources, the new data has to be merged into the 43X server resources database. Depending on the circumstances, the 44following command may do the trick. See xrdb(1) for more information. 45 46 $ xrdb -merge ~/.Xresources 47 48** Emacs compiled with Cairo crashes when restoring session from desktop file. 49 50This can happen if the '.emacs.desktop' file contains setting for 51'font-backend' frame parameter. A workaround is to delete the 52offending '.emacs.desktop' file, or edit it to remove the setting of 53'font-backend'. 54 55** Emacs aborts while starting up, only when run without X. 56 57This problem often results from compiling Emacs with GCC when GCC was 58installed incorrectly. The usual error in installing GCC is to 59specify --includedir=/usr/include. Installation of GCC makes 60corrected copies of the system header files. GCC is supposed to use 61the corrected copies in preference to the original system headers. 62Specifying --includedir=/usr/include causes the original system header 63files to be used. On some systems, the definition of ioctl in the 64original system header files is invalid for ANSI C and causes Emacs 65not to work. 66 67The fix is to reinstall GCC, and this time do not specify --includedir 68when you configure it. Then recompile Emacs. Specifying --includedir 69is appropriate only in very special cases and it should *never* be the 70same directory where system header files are kept. 71 72** Emacs does not start, complaining that it cannot open termcap database file. 73 74If your system uses Terminfo rather than termcap (most modern 75systems do), this could happen if the proper version of 76ncurses is not visible to the Emacs configure script (i.e. it 77cannot be found along the usual path the linker looks for 78libraries). It can happen because your version of ncurses is 79obsolete, or is available only in form of binaries. 80 81The solution is to install an up-to-date version of ncurses in 82the developer's form (header files, static libraries and 83symbolic links); in some GNU/Linux distributions (e.g. Debian) 84it constitutes a separate package. 85 86** Emacs 20 and later fails to load Lisp files at startup. 87 88The typical error message might be like this: 89 90 "Cannot open load file: fontset" 91 92This could happen if you compress the file lisp/subdirs.el. That file 93tells Emacs what are the directories where it should look for Lisp 94files. Emacs cannot work with subdirs.el compressed, since the 95Auto-compress mode it needs for this will not be loaded until later, 96when your .emacs file is processed. (The package 'fontset.el' is 97required to set up fonts used to display text on window systems, and 98it's loaded very early in the startup procedure.) 99 100Similarly, any other .el file for which there's no corresponding .elc 101file could fail to load if it is compressed. 102 103The solution is to uncompress all .el files that don't have a .elc file. 104 105Another possible reason for such failures is stale *.elc files 106lurking somewhere on your load-path -- see the next section. 107 108** Emacs prints an error at startup after upgrading from an earlier version. 109 110An example of such an error is: 111 112 x-complement-fontset-spec: "Wrong type argument: stringp, nil" 113 114This can be another symptom of stale *.elc files in your load-path. 115The following command will print any duplicate Lisp files that are 116present in load-path: 117 118 emacs -batch -f list-load-path-shadows 119 120If this command prints any file names, some of these files are stale, 121and should be deleted or their directories removed from your 122load-path. 123 124* Crash bugs 125 126** Emacs crashes when running in a terminal, if compiled with GCC 4.5.0 127 128This version of GCC is buggy: see 129 130 https://debbugs.gnu.org/6031 131 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43904 132 133You can work around this error in gcc-4.5 by omitting sibling call 134optimization. To do this, configure Emacs with 135 136 ./configure CFLAGS="-g -O2 -fno-optimize-sibling-calls" 137 138** Emacs compiled with GCC 4.6.1 crashes on MS-Windows when C-g is pressed 139 140This is known to happen when Emacs is compiled with MinGW GCC 4.6.1 141with the -O2 option (which is the default in the Windows build). The 142reason is a bug in MinGW GCC 4.6.1; to work around, either add the 143'-fno-omit-frame-pointer' switch to GCC or compile without 144optimizations ('--no-opt' switch to the configure.bat script). 145 146** Emacs crashes in x-popup-dialog. 147 148This can happen if the dialog widget cannot find the font it wants to 149use. You can work around the problem by specifying another font with 150an X resource--for example, 'Emacs.dialog*.font: 9x15' (or any font that 151happens to exist on your X server). 152 153** Emacs crashes when you use Bibtex mode. 154 155This happens if your system puts a small limit on stack size. You can 156prevent the problem by using a suitable shell command (often 'ulimit') 157to raise the stack size limit before you run Emacs. 158 159Patches to raise the stack size limit automatically in 'main' 160(src/emacs.c) on various systems would be greatly appreciated. 161 162** Error message 'Symbol’s value as variable is void: x', followed by 163a segmentation fault and core dump. 164 165This has been tracked to a bug in tar! People report that tar erroneously 166added a line like this at the beginning of files of Lisp code: 167 168 x FILENAME, N bytes, B tape blocks 169 170If your tar has this problem, install GNU tar--if you can manage to 171untar it :-). 172 173** Emacs can crash when displaying PNG images with transparency. 174 175This is due to a bug introduced in ImageMagick 6.8.2-3. The bug should 176be fixed in ImageMagick 6.8.3-10. See <URL:https://debbugs.gnu.org/13867>. 177 178** Crashes when displaying GIF images in Emacs built with version 179libungif-4.1.0 are resolved by using version libungif-4.1.0b1. 180Configure checks for the correct version, but this problem could occur 181if a binary built against a shared libungif is run on a system with an 182older version. 183 184** Emacs aborts inside the function 'tparam1'. 185 186This can happen if Emacs was built without terminfo support, but the 187terminal's capabilities use format that is only supported by terminfo. 188If your system has ncurses installed, this might happen if your 189version of ncurses is broken; upgrading to a newer version of ncurses 190and reconfiguring and rebuilding Emacs should solve this. 191 192All modern systems support terminfo, so even if ncurses is not the 193problem, you should look for a way to configure Emacs so that it uses 194terminfo when built. 195 196** Emacs crashes when using some version of the Exceed X server. 197 198Upgrading to a newer version of Exceed has been reported to prevent 199these crashes. You should consider switching to a free X server, such 200as Xming or Cygwin/X. 201 202** Emacs crashes with SIGSEGV in XtInitializeWidgetClass. 203 204It crashes on X, but runs fine when called with option "-nw". 205 206This has been observed when Emacs is linked with GNU ld but without passing 207the -z nocombreloc flag. Emacs normally knows to pass the -z nocombreloc 208flag when needed, so if you come across a situation where the flag is 209necessary but missing, please report it via M-x report-emacs-bug. 210 211On platforms such as Solaris, you can also work around this problem by 212configuring your compiler to use the native linker instead of GNU ld. 213 214** When Emacs is compiled with Gtk+, closing a display kills Emacs. 215 216There is a long-standing bug in GTK that prevents it from recovering 217from disconnects: https://gitlab.gnome.org/GNOME/gtk/issues/221 218 219Thus, for instance, when Emacs is run as a server on a text terminal, 220and an X frame is created, and the X server for that frame crashes or 221exits unexpectedly, Emacs must exit to prevent a GTK error that would 222result in an endless loop. 223 224If you need Emacs to be able to recover from closing displays, compile 225it with the Lucid toolkit instead of GTK. 226 227** Emacs compiled with GTK+ 3 crashes when run under some X servers. 228This happens when the X server does not provide certain display 229features that the underlying GTK+ 3 toolkit assumes. For example, this 230issue has been seen with remote X servers like X2Go. The symptoms 231are an Emacs crash, possibly triggered by the mouse entering the Emacs 232window, or an attempt to resize the Emacs window. The crash backtrace 233contains a call to XQueryPointer. 234 235This issue was fixed in the GTK+ 3 toolkit in commit 4b1c0256 in February 2018. 236 237If your GTK+ 3 is still affected, you can avoid the issue by recompiling 238Emacs with a different X toolkit, eg --with-toolkit=gtk2. 239 240References: 241https://gitlab.gnome.org/GNOME/gtk/commit/4b1c02560f0d8097bf5a11932e52fb72f3e9e94b 242https://debbugs.gnu.org/24280 243https://bugs.debian.org/901038 244https://bugzilla.redhat.com/1483942 245https://access.redhat.com/solutions/3410101 246 247** Emacs compiled with GTK crashes at startup due to X protocol error. 248 249This is known to happen on elementary OS GNU/Linux systems. 250 251The error message is: 252 253 X protocol error: BadMatch (invalid parameter attributes) on protocol request 140 254 When compiled with GTK, Emacs cannot recover from X disconnects. 255 This is a GTK bug: https://gitlab.gnome.org/GNOME/gtk/issues/221 256 For details, see etc/PROBLEMS. 257 Fatal error 6: Aborted 258 259followed by a C backtrace. (Sometimes the offending protocol request 260number is 139.) 261 262The relevant bug report is here: 263 264 https://bugs.launchpad.net/elementaryos/+bug/1355274 265 266A workaround is to set XLIB_SKIP_ARGB_VISUALS=1 in the environment 267before starting Emacs, or run Emacs as root. 268 269** Emacs crashes when you try to view a file with complex characters. 270 271One possible reason for this could be a bug in the libotf or the 272libm17n-flt/m17n-db libraries Emacs uses for displaying complex 273scripts. Make sure you have the latest versions of these libraries 274installed. If the problem still persists with the latest released 275versions of these libraries, you can try building these libraries from 276their CVS repository: 277 278 cvs -z3 -d:pserver:anonymous@cvs.savannah.nongnu.org:/sources/m17n co libotf 279 cvs -z3 -d:pserver:anonymous@cvs.savannah.nongnu.org:/sources/m17n co m17n-db 280 cvs -z3 -d:pserver:anonymous@cvs.savannah.nongnu.org:/sources/m17n co m17n-lib 281 282One known problem that causes such crashes is with using Noto Serif 283Kannada fonts. To work around that, force Emacs not to select these 284fonts, by adding the following to your ~/.emacs init file: 285 286 (push "Noto Serif Kannada" face-ignored-fonts) 287 288You can try this interactively in a running Emacs session like this: 289 290 M-: (push "Noto Serif Kannada" face-ignored-fonts) RET 291 292Another set of problems is caused by an incompatible libotf library. 293In this case, displaying the etc/HELLO file (as shown by C-h h) 294triggers the following message to be shown in the terminal from which 295you launched Emacs: 296 297 symbol lookup error: /usr/bin/emacs: undefined symbol: OTF_open 298 299This problem occurs because unfortunately there are two libraries 300called "libotf". One is the library for handling OpenType fonts, 301https://www.nongnu.org/m17n/, which is the one that Emacs expects. 302The other is a library for Open Trace Format, and is used by some 303versions of the MPI message passing interface for parallel 304programming. 305 306For example, on RHEL6 GNU/Linux, the OpenMPI rpm provides a version 307of "libotf.so" in /usr/lib/openmpi/lib. This directory is not 308normally in the ld search path, but if you want to use OpenMPI, 309you must issue the command "module load openmpi". This adds 310/usr/lib/openmpi/lib to LD_LIBRARY_PATH. If you then start Emacs from 311the same shell, you will encounter this crash. 312Ref: <URL:https://bugzilla.redhat.com/show_bug.cgi?id=844776> 313 314There is no good solution to this problem if you need to use both 315OpenMPI and Emacs with libotf support. The best you can do is use a 316wrapper shell script (or function) "emacs" that removes the offending 317element from LD_LIBRARY_PATH before starting emacs proper. 318Or you could recompile Emacs with an -Wl,-rpath option that 319gives the location of the correct libotf. 320 321* General runtime problems 322 323** Lisp problems 324 325*** Changes made to .el files do not take effect. 326 327You may have forgotten to recompile them into .elc files. 328Then the old .elc files will be loaded, and your changes 329will not be seen. To fix this, do M-x byte-recompile-directory 330and specify the directory that contains the Lisp files. 331 332Emacs prints a warning when loading a .elc file which is older 333than the corresponding .el file. 334 335Alternatively, if you set the option 'load-prefer-newer' non-nil, 336Emacs will load whichever version of a file is the newest. 337 338*** Watch out for the EMACSLOADPATH environment variable 339 340EMACSLOADPATH overrides which directories the function "load" will search. 341 342If you observe strange problems, check for this variable in your 343environment. 344 345*** Using epop3.el package causes Emacs to signal an error. 346 347The error message might be something like this: 348 349 "Lisp nesting exceeds max-lisp-eval-depth" 350 351This happens because epop3 redefines the function gethash, which is a 352built-in primitive beginning with Emacs 21.1. We don't have a patch 353for epop3 to fix it, but perhaps a newer version of epop3 corrects that. 354 355*** Buffers from 'with-output-to-temp-buffer' get set up in Help mode. 356 357Changes in Emacs 20.4 to the hooks used by that function cause 358problems for some packages, specifically BBDB. See the function's 359documentation for the hooks involved. BBDB 2.00.06 fixes the problem. 360 361*** The Hyperbole package causes *Help* buffers not to be displayed in 362Help mode due to setting 'temp-buffer-show-hook' rather than using 363'add-hook'. Using '(add-hook 'temp-buffer-show-hook 'help-mode-finish)' 364after loading Hyperbole should fix this. 365 366** Keyboard problems 367 368*** Unable to enter the M-| key on some German keyboards. 369Some users have reported that M-| suffers from "keyboard ghosting". 370This can't be fixed by Emacs, as the keypress never gets passed to it 371at all (as can be verified using "xev"). You can work around this by 372typing 'ESC |' instead. 373 374*** "Compose Character" key does strange things when used as a Meta key. 375 376If you define one key to serve as both Meta and Compose Character, you 377will get strange results. In previous Emacs versions, this "worked" 378in that the key acted as Meta--that's because the older Emacs versions 379did not try to support Compose Character. Now Emacs tries to do 380character composition in the standard X way. This means that you 381must pick one meaning or the other for any given key. 382 383You can use both functions (Meta, and Compose Character) if you assign 384them to two different keys. 385 386*** C-z just refreshes the screen instead of suspending Emacs. 387 388You are probably using a shell that doesn't support job control, even 389though the system itself is capable of it. Either use a different shell, 390or set the variable 'cannot-suspend' to a non-nil value. 391 392** Mailers and other helper programs 393 394*** movemail compiled with POP support can't connect to the POP server. 395 396This problem can occur if you do not configure --with-mailutils, 397and don't have GNU Mailutils installed. Then Emacs uses its own 398version of movemail, which doesn't support secure POP connections. 399To solve this, install GNU Mailutils. 400 401Also, make sure that the 'pop' entry in /etc/services, or in the 402services NIS map if your machine uses NIS, has the same port number as 403the entry on the POP server. A common error is for the POP server to 404be listening on port 110, the assigned port for the POP3 protocol, 405while the client is trying to connect on port 109, the assigned port 406for the old POP protocol. 407 408*** RMAIL gets error getting new mail. 409 410RMAIL gets new mail from /usr/spool/mail/$USER using a program 411called 'movemail'. This program interlocks with /bin/mail using 412the protocol defined by /bin/mail. 413 414There are two different protocols in general use. One of them uses 415the 'flock' system call. The other involves creating a lock file; 416'movemail' must be able to write in /usr/spool/mail in order to do 417this. You control which one is used by defining, or not defining, 418the macro MAIL_USE_FLOCK in config.h. 419IF YOU DON'T USE THE FORM OF INTERLOCKING THAT IS NORMAL ON YOUR 420SYSTEM, YOU CAN LOSE MAIL! 421 422If your system uses the lock file protocol, and fascist restrictions 423prevent ordinary users from writing the lock files in /usr/spool/mail, 424you may need to make 'movemail' setgid to a suitable group such as 425'mail'. To do this, use the following commands (as root) after doing the 426make install. 427 428 chgrp mail movemail 429 chmod 2755 movemail 430 431Installation normally copies movemail from the build directory to an 432installation directory which is usually under /usr/local/lib. The 433installed copy of movemail is usually in the directory 434/usr/local/lib/emacs/VERSION/TARGET. You must change the group and 435mode of the installed copy; changing the group and mode of the build 436directory copy is ineffective. 437 438*** rcs2log gives you the awk error message "too many fields". 439 440This is due to an arbitrary limit in certain versions of awk. 441The solution is to use gawk (GNU awk). 442 443** Problems with hostname resolution 444 445*** Emacs does not know your host's fully-qualified domain name. 446 447For example, (system-name) returns some variation on 448"localhost.localdomain", rather the name you were expecting. 449 450You need to configure your machine with a fully qualified domain name, 451(i.e., a name with at least one "."), either in /etc/hostname 452or wherever your system calls for specifying this. 453 454If you cannot fix the configuration, you can set the Lisp variable 455mail-host-address to the value you want. 456 457** NFS 458 459*** Emacs says it has saved a file, but the file does not actually 460appear on disk. 461 462This can happen on certain systems when you are using NFS, if the 463remote disk is full. It is due to a bug in NFS (or certain NFS 464implementations), and there is apparently nothing Emacs can do to 465detect the problem. Emacs checks the failure codes of all the system 466calls involved in writing a file, including 'close'; but in the case 467where the problem occurs, none of those system calls fails. 468 469** PSGML conflicts with sgml-mode. 470 471PSGML package uses the same names of some variables (like keymap) 472as built-in sgml-mode.el because it was created as a replacement 473of that package. The conflict will be shown if you load 474sgml-mode.el before psgml.el. E.g. this could happen if you edit 475HTML page and then start to work with SGML or XML file. html-mode 476(from sgml-mode.el) is used for HTML file and loading of psgml.el 477(for sgml-mode or xml-mode) will cause an error. 478 479** PCL-CVS 480 481*** Lines are not updated or new lines are added in the buffer upon commit. 482 483When committing files located higher in the hierarchy than the examined 484directory, some versions of the CVS program return an ambiguous message 485from which PCL-CVS cannot extract the full location of the committed 486files. As a result, the corresponding lines in the PCL-CVS buffer are 487not updated with the new revision of these files, and new lines are 488added to the top-level directory. 489 490This can happen with CVS versions 1.12.8 and 1.12.9. Upgrade to CVS 4911.12.10 or newer to fix this problem. 492 493** Miscellaneous problems 494 495*** Editing files with very long lines is slow. 496 497For example, simply moving through a file that contains hundreds of 498thousands of characters per line is slow, and consumes a lot of CPU. 499This is a known limitation of Emacs with no solution at this time. 500 501*** Emacs uses 100% of CPU time 502 503This was a known problem with some old versions of the Semantic package. 504The solution was to upgrade Semantic to version 2.0pre4 (distributed 505with CEDET 1.0pre4) or later. Note that Emacs includes Semantic since 50623.2, and this issue does not apply to the included version. 507 508*** Display artifacts on GUI frames on X-based systems. 509 510This is known to be caused by using double-buffering (which is enabled 511by default in Emacs 26 and later). The artifacts typically appear 512after commands that cause Emacs to scroll the display. 513 514You can disable double-buffering by evaluating the following form: 515 516 (modify-all-frames-parameters '((inhibit-double-buffering . t))) 517 518To make this permanent, add it to your ~/.emacs init file. 519 520Note that disabling double-buffering will cause flickering of the 521display in some situations. 522 523*** Self-documentation messages are garbled. 524 525This means that the file 'etc/DOC' doesn't properly correspond 526with the Emacs executable. Redumping Emacs and then installing the 527corresponding pair of files should fix the problem. 528 529*** Programs running under terminal emulator do not recognize 'emacs' 530terminal type. 531 532The cause of this is a shell startup file that sets the TERMCAP 533environment variable. The terminal emulator uses that variable to 534provide the information on the special terminal type that Emacs emulates. 535 536Rewrite your shell startup file so that it does not change TERMCAP 537in such a case. You could use the following conditional which sets 538it only if it is undefined. 539 540 if ( ! ${?TERMCAP} ) setenv TERMCAP ~/my-termcap-file 541 542Or you could set TERMCAP only when you set TERM--which should not 543happen in a non-login shell. 544 545*** In Shell mode, you get a ^M at the end of every line. 546 547This happens to people who use tcsh, because it is trying to be too 548smart. It sees that the Shell uses terminal type 'unknown' and turns 549on the flag to output ^M at the end of each line. You can fix the 550problem by adding this to your .cshrc file: 551 552 if ($?INSIDE_EMACS && $?tcsh) 553 unset edit 554 stty -icrnl -onlcr -echo susp ^Z 555 endif 556 557*** In Shell buffers using ksh, resizing a window inserts random characters. 558 559The characters come from the PS2 prompt, but they are not followed by 560a newline, which messes up the next command you type. This strange 561effect is caused by Emacs 25 and later telling the shell that its 562screen size changed. 563 564To work around the problem, customize the option 565'window-adjust-process-window-size-function' to "Do not adjust process 566window sizes" (Lisp value 'ignore'). 567 568*** In Inferior Python mode, input is echoed and native completion doesn't work. 569<https://debbugs.gnu.org/cgi/bugreport.cgi?bug=25753> 570 571This happens when python uses a libedit based readline module, which 572is the default on macOS. This can be worked around by installing a 573GNU readline based module instead, for example, using setuptools 574 575 sudo easy_install gnureadline 576 577And then rename the system's readline so that it won't be loaded: 578 579 cd /Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-dynload 580 mv readline.so readline.so.bak 581 582See <https://pypi.python.org/pypi/gnureadline> for more details on 583installation. 584 585*** Visiting files in some auto-mounted directories causes Emacs to print 586'Error reading dir-locals: (file-error "Read error" "is a directory" ...' 587 588This can happen if the auto-mounter mistakenly reports that 589.dir-locals.el exists and is a directory. There is nothing Emacs can 590do about this, but you can avoid the issue by adding a suitable entry 591to the variable 'locate-dominating-stop-dir-regexp'. For example, if 592the problem relates to "/smb/.dir-locals.el", set that variable 593to a new value where you replace "net\\|afs" with "net\\|afs\\|smb". 594(The default value already matches common auto-mount prefixes.) 595See https://lists.gnu.org/r/help-gnu-emacs/2015-02/msg00461.html . 596 597*** Attempting to visit remote files via ange-ftp fails. 598 599If the error message is "ange-ftp-file-modtime: Specified time is not 600representable", then this could happen when 'lukemftp' is used as the 601ftp client. This was reported to happen on Debian GNU/Linux, kernel 602version 2.4.3, with 'lukemftp' 1.5-5, but might happen on other 603systems as well. To avoid this problem, switch to using the standard 604ftp client. On a Debian system, type 605 606 update-alternatives --config ftp 607 608and then choose /usr/bin/netkit-ftp. 609 610*** Dired is very slow. 611 612This could happen if getting a file system's status takes a long 613time. Possible reasons for this include: 614 615 - ClearCase mounted filesystems (VOBs) that sometimes make 'df' 616 response time extremely slow (dozens of seconds); 617 618 - slow automounters on some old versions of Unix; 619 620To work around the problem, you could use Git or some other 621free-software program, instead of ClearCase. 622 623*** ps-print commands fail to find prologue files ps-prin*.ps. 624 625This can happen if you use an old version of X-Symbol package: it 626defines compatibility functions which trick ps-print into thinking it 627runs in XEmacs, and look for the prologue files in a wrong directory. 628 629The solution is to upgrade X-Symbol to a later version. 630 631*** On systems with shared libraries you might encounter run-time errors 632from the dynamic linker telling you that it is unable to find some 633shared libraries, for instance those for Xaw3d or image support. 634These errors mean Emacs has been linked with a library whose shared 635library is not in the default search path of the dynamic linker. 636 637Similar problems could prevent Emacs from building, since the build 638process invokes Emacs several times. 639 640On many systems, it is possible to set LD_LIBRARY_PATH in your 641environment to specify additional directories where shared libraries 642can be found. 643 644Other systems allow to set LD_RUN_PATH in a similar way, but before 645Emacs is linked. With LD_RUN_PATH set, the linker will include a 646specified run-time search path in the executable. 647 648Please refer to the documentation of your dynamic linker for details. 649 650*** When you run Ispell from Emacs, it reports a "misalignment" error. 651 652This can happen if you compiled the Ispell program to use ASCII 653characters only and then try to use it from Emacs with non-ASCII 654characters, like Latin-1. The solution is to recompile Ispell with 655support for 8-bit characters. 656 657To see whether your Ispell program supports 8-bit characters, type 658this at your shell's prompt: 659 660 ispell -vv 661 662and look in the output for the string "NO8BIT". If Ispell says 663"!NO8BIT (8BIT)", your speller supports 8-bit characters; otherwise it 664does not. 665 666To rebuild Ispell with 8-bit character support, edit the local.h file 667in the Ispell distribution and make sure it does _not_ define NO8BIT. 668Then rebuild the speller. 669 670Another possible cause for "misalignment" error messages is that the 671version of Ispell installed on your machine is old. Upgrade. 672 673Yet another possibility is that you are trying to spell-check a word 674in a language that doesn't fit the dictionary you choose for use by 675Ispell. (Ispell can only spell-check one language at a time, because 676it uses a single dictionary.) Make sure that the text you are 677spelling and the dictionary used by Ispell conform to each other. 678 679If your spell-checking program is Aspell, it has been reported that if 680you have a personal configuration file (normally ~/.aspell.conf), it 681can cause this error. Remove that file, execute 'ispell-kill-ispell' 682in Emacs, and then try spell-checking again. 683 684*** TLS problems, e.g., Gnus hangs when fetching via imaps 685https://debbugs.gnu.org/24247 686 687gnutls-cli 3.5.3 (2016-08-09) does not generate a "- Handshake was 688completed" message that tls.el relies upon, causing affected Emacs 689functions to hang. To work around the problem, use older or newer 690versions of gnutls-cli, or use Emacs's built-in gnutls support. 691 692* Runtime problems related to font handling 693 694** Characters are displayed as empty boxes or with wrong font under X. 695 696*** This may be due to your local fontconfig customization. 697Try removing or moving aside "$XDG_CONFIG_HOME/fontconfig/conf.d" and 698"$XDG_CONFIG_HOME/fontconfig/fonts.conf" 699($XDG_CONFIG_HOME is treated as "~/.config" if not set) 700 701*** This can occur when two different versions of FontConfig are used. 702For example, XFree86 4.3.0 has one version and Gnome usually comes 703with a newer version. Emacs compiled with Gtk+ will then use the 704newer version. In most cases the problem can be temporarily fixed by 705stopping the application that has the error (it can be Emacs or any 706other application), removing ~/.fonts.cache-1, and then starting the 707application again. If removing ~/.fonts.cache-1 and restarting 708doesn't help, the application with problem must be recompiled with the 709same version of FontConfig as the rest of the system uses. For KDE, 710it is sufficient to recompile Qt. 711 712*** Some fonts have a missing glyph and no default character. This is 713known to occur for character number 160 (no-break space) in some 714fonts, such as Lucida but Emacs sets the display table for the unibyte 715and Latin-1 version of this character to display a space. 716 717*** Some of the fonts called for in your fontset may not exist on your 718X server. 719 720Each X font covers just a fraction of the characters that Emacs 721supports. To display the whole range of Emacs characters requires 722many different fonts, collected into a fontset. You can remedy the 723problem by installing additional fonts. 724 725The intlfonts distribution includes a full spectrum of fonts that can 726display all the characters Emacs supports. The etl-unicode collection 727of fonts (available from 728<https://ftp.nluug.nl/windowing/X/contrib/fonts/>) includes fonts that 729can display many Unicode characters; they can also be used by ps-print 730and ps-mule to print Unicode characters. 731 732** Under X, some characters appear improperly aligned in their lines. 733 734You may have bad fonts. 735 736** Under X, some characters are unexpectedly wide. 737 738e.g. recent versions of Inconsolata show this issue for almost all of 739its characters. Due to what is probably an Xft bug, the determination 740of the width of some characters is incorrect. One workaround is to 741build emacs with Cairo enabled ("configure --with-cairo" and have the 742appropriate Cairo development packages installed) as this 743configuration does not suffer from this problem. See 744<https://github.com/googlefonts/Inconsolata/issues/42> and 745<https://lists.gnu.org/archive/html/bug-gnu-emacs/2020-01/msg00456.html> 746for more discussion. 747 748** Under X, an unexpected monospace font is used as the default font. 749 750When compiled with XFT, Emacs tries to use a default font named 751"monospace". This is a "virtual font", which the operating system 752(Fontconfig) redirects to a suitable font such as DejaVu Sans Mono. 753On some systems, there exists a font that is actually named Monospace, 754which takes over the virtual font. This is considered an operating 755system bug; see 756 757https://lists.gnu.org/r/emacs-devel/2008-10/msg00696.html 758 759If you encounter this problem, set the default font to a specific font 760in your .Xresources or initialization file. For instance, you can put 761the following in your .Xresources: 762 763Emacs.font: DejaVu Sans Mono 12 764 765** Certain fonts make each line take one pixel more than it should. 766 767This is because these fonts contain characters a little taller than 768the font's nominal height. Emacs needs to make sure that lines do not 769overlap. 770 771** Font Lock displays portions of the buffer in incorrect faces. 772 773By far the most frequent cause of this is a parenthesis '(' or a brace 774'{' in column zero. Font Lock assumes that such a paren is outside of 775any comment or string. This is of course not true in general, but the 776vast majority of well-formatted program source files don't have such 777parens, and therefore this assumption is used to allow optimizations 778in Font Lock's syntactical analysis. These optimizations avoid some 779pathological cases where jit-lock, the Just-in-Time fontification 780introduced with Emacs 21.1, could significantly slow down scrolling 781through the buffer, especially scrolling backwards, and also jumping 782to the end of a very large buffer. 783 784Beginning with version 22.1, a parenthesis or a brace in column zero 785is highlighted in bold-red face if it is inside a string or a comment, 786to indicate that it could interfere with Font Lock (and also with 787indentation) and should be moved or escaped with a backslash. 788 789If you don't use large buffers, or have a very fast machine which 790makes the delays insignificant, you can avoid the incorrect 791fontification by setting the variable 792'font-lock-beginning-of-syntax-function' to a nil value. (This must 793be done _after_ turning on Font Lock.) 794 795Another alternative is to avoid a paren in column zero. For example, 796in a Lisp string you could precede the paren with a backslash. 797 798** Emacs pauses for several seconds when changing the default font. 799 800This has been reported for fvwm 2.2.5 and the window manager of KDE 8012.1. The reason for the pause is Xt waiting for a ConfigureNotify 802event from the window manager, which the window manager doesn't send. 803Xt stops waiting after a default timeout of usually 5 seconds. 804 805A workaround for this is to add something like 806 807emacs.waitForWM: false 808 809to your X resources. Alternatively, add '(wait-for-wm . nil)' to a 810frame's parameter list, like this: 811 812 (modify-frame-parameters nil '((wait-for-wm . nil))) 813 814(this should go into your '.emacs' file). 815 816** Underlines appear at the wrong position. 817 818This is caused by fonts having a wrong UNDERLINE_POSITION property. 819To avoid this problem (seen in some very old X releases and font packages), 820set x-use-underline-position-properties to nil. 821 822To see what is the value of UNDERLINE_POSITION defined by the font, 823type 'xlsfonts -lll FONT' and look at the font's UNDERLINE_POSITION property. 824 825** When using Exceed, fonts sometimes appear too tall. 826 827When the display is set to an Exceed X-server and fonts are specified 828(either explicitly with the -fn option or implicitly with X resources) 829then the fonts may appear "too tall". The actual character sizes are 830correct but there is too much vertical spacing between rows, which 831gives the appearance of "double spacing". 832 833To prevent this, turn off the Exceed's "automatic font substitution" 834feature (in the font part of the configuration window). 835 836** Subscript/superscript text in TeX is hard to read. 837 838If 'tex-fontify-script' is non-nil, tex-mode displays 839subscript/superscript text in the faces subscript/superscript, which 840are smaller than the normal font and lowered/raised. With some fonts, 841nested superscripts (say) can be hard to read. Switching to a 842different font, or changing your antialiasing setting (on an LCD 843screen), can both make the problem disappear. Alternatively, customize 844the following variables: tex-font-script-display (how much to 845lower/raise); tex-suscript-height-ratio (how much smaller than 846normal); tex-suscript-height-minimum (minimum height). 847 848** Screen refresh is slow when there are special characters for which no suitable font is available 849 850If the display is too slow in refreshing when you scroll to a new 851region, or when you edit the buffer, it might be due to the fact that 852some characters cannot be displayed in the default font, and Emacs is 853spending too much time in looking for a suitable font to display them. 854 855You can suspect this if you have several characters that are displayed 856as small rectangles containing a hexadecimal code inside. 857 858The solution is to install the appropriate fonts on your machine. For 859instance if you are editing a text with a lot of math symbols, then 860installing a font like 'Symbola' should solve this problem. 861 862Another reason for slow display is reportedly the nerd-fonts 863installation, even when Symbola is installed as well. Uninstalling 864nerd-fonts was reported to solve the problem in that case. 865 866** Emacs running on GNU/Linux system with the m17n library Ver.1.7.1 or the 867earlier version has a problem with rendering Bengali script. 868 869The problem can be fixed by installing the newer version of the m17n 870library (if any), or by following this procedure: 871 8721. Locate the file BENG-OTF.flt installed on your system as part of the 873m17n library. Usually it is under the directory /usr/share/m17n. 874 8752. Apply the following patch to BENG-OTF.flt 876 877------------------------------------------------------------ 878diff --git a/FLT/BENG-OTF.flt b/FLT/BENG-OTF.flt 879index 45cc554..0cc5e76 100644 880--- a/FLT/BENG-OTF.flt 881+++ b/FLT/BENG-OTF.flt 882@@ -232,7 +232,7 @@ 883 (lang-forms 884 (cond 885 ("(.H)J" (1 :otf=beng=half+)) 886- (".H" :otf=beng=blwf,half,vatu+) 887+ (".+H" :otf=beng=blwf,half,vatu+) 888 ("." =))) 889 890 (post 891------------------------------------------------------------ 892 893If you can't modify that file directly, copy it to the directory 894~/.m17n.d/ (create it if it doesn't exist), and apply the patch. 895 896** Emacs running on GNU/Linux system with the m17n library Ver.1.7.1 or the 897earlier version has a problem with rendering Lao script with OpenType font. 898 899The problem can be fixed by installing the newer version of the m17n 900library (if any), or by following this procedure: 901 9021. Locate the file LAOO-OTF.flt installed on your system as part of the 903m17n library. Usually it is under the directory /usr/share/m17n. 904 9052. Apply the following patch to LAOO-OTF.flt 906 907------------------------------------------------------------ 908diff --git a/FLT/LAOO-OTF.flt b/FLT/LAOO-OTF.flt 909index 5504171..431adf8 100644 910--- a/FLT/LAOO-OTF.flt 911+++ b/FLT/LAOO-OTF.flt 912@@ -3,7 +3,7 @@ 913 ;; See the end for copying conditions. 914 915 (font layouter laoo-otf nil 916- (font (nil phetsarath\ ot unicode-bmp))) 917+ (font (nil nil unicode-bmp :otf=lao\ ))) 918 919 ;;; <li> LAOO-OTF.flt 920 921------------------------------------------------------------ 922 923If you can't modify that file directly, copy it to the directory 924~/.m17n.d/ (create it if it doesn't exist), and apply the patch. 925 926** On MS-Windows, some characters display as boxes with hex code. 927 928Also, some characters could display with wrong fonts. 929 930This can happen if Emacs was compiled without HarfBuzz support, and/or 931if the HarfBuzz DLLs are not available at run time. Emacs will then 932fall back to the Uniscribe as its shaping engine; Uniscribe was 933deprecated by Microsoft, and sometimes fails to display correctly when 934modern fonts are used, such as Noto Emoji or Ebrima. 935 936The solution is to switch to a configuration that uses HarfBuzz as its 937shaping engine, where these problems don't exist. 938 939* Internationalization problems 940 941** M-{ does not work on a Spanish PC keyboard. 942 943Many Spanish keyboards seem to ignore that combination. Emacs can't 944do anything about it. 945 946** International characters aren't displayed under X. 947 948*** Missing X fonts 949 950XFree86 4 contains many fonts in iso10646-1 encoding which have 951minimal character repertoires (whereas the encoding part of the font 952name is meant to be a reasonable indication of the repertoire 953according to the XLFD spec). Emacs may choose one of these to display 954characters from the mule-unicode charsets and then typically won't be 955able to find the glyphs to display many characters. (Check with C-u 956C-x = .) To avoid this, you may need to use a fontset which sets the 957font for the mule-unicode sets explicitly. E.g. to use GNU unifont, 958include in the fontset spec: 959 960mule-unicode-2500-33ff:-gnu-unifont-*-iso10646-1,\ 961mule-unicode-e000-ffff:-gnu-unifont-*-iso10646-1,\ 962mule-unicode-0100-24ff:-gnu-unifont-*-iso10646-1 963 964** The UTF-8/16/7 coding systems don't encode CJK (Far Eastern) characters. 965 966Emacs directly supports the Unicode BMP whose code points are in the 967ranges 0000-33ff and e000-ffff, and indirectly supports the parts of 968CJK characters belonging to these legacy charsets: 969 970 GB2312, Big5, JISX0208, JISX0212, JISX0213-1, JISX0213-2, KSC5601 971 972The latter support is done in Utf-Translate-Cjk mode (turned on by 973default). Which Unicode CJK characters are decoded into which Emacs 974charset is decided by the current language environment. For instance, 975in Chinese-GB, most of them are decoded into chinese-gb2312. 976 977If you read UTF-8 data with code points outside these ranges, the 978characters appear in the buffer as raw bytes of the original UTF-8 979(composed into a single quasi-character) and they will be written back 980correctly as UTF-8, assuming you don't break the composed sequences. 981If you read such characters from UTF-16 or UTF-7 data, they are 982substituted with the Unicode 'replacement character', and you lose 983information. 984 985** Accented ISO-8859-1 characters are displayed as | or _. 986 987Try other font set sizes (S-mouse-1). If the problem persists with 988other sizes as well, your text is corrupted, probably through software 989that is not 8-bit clean. If the problem goes away with another font 990size, it's probably because some fonts pretend to be ISO-8859-1 fonts 991when they are really ASCII fonts. In particular the schumacher-clean 992fonts have this bug in some versions of X. 993 994To see what glyphs are included in a font, use 'xfd', like this: 995 996 xfd -fn -schumacher-clean-medium-r-normal--12-120-75-75-c-60-iso8859-1 997 998If this shows only ASCII glyphs, the font is indeed the source of the problem. 999 1000The solution is to remove the corresponding lines from the appropriate 1001'fonts.alias' file, then run 'mkfontdir' in that directory, and then run 1002'xset fp rehash'. 1003 1004** The 'oc-unicode' package doesn't work with Emacs 21. 1005 1006This package tries to define more private charsets than there are free 1007slots now. The current built-in Unicode support is actually more 1008flexible. (Use option 'utf-translate-cjk-mode' if you need CJK 1009support.) Files encoded as emacs-mule using oc-unicode aren't 1010generally read correctly by Emacs 21. 1011 1012* X runtime problems 1013 1014** X keyboard problems 1015 1016*** You "lose characters" after typing Compose Character key. 1017 1018This is because the Compose Character key is defined as the keysym 1019Multi_key, and Emacs (seeing that) does the proper X 1020character-composition processing. If you don't want your Compose key 1021to do that, you can redefine it with xmodmap. 1022 1023For example, here's one way to turn it into a Meta key: 1024 1025 xmodmap -e "keysym Multi_key = Meta_L" 1026 1027If all users at your site of a particular keyboard prefer Meta to 1028Compose, you can make the remapping happen automatically by adding the 1029xmodmap command to the xdm setup script for that display. 1030 1031*** Using X Window System, control-shift-leftbutton makes Emacs hang. 1032 1033Use the shell command 'xset bc' to make the old X Menu package work. 1034 1035*** C-SPC fails to work on Fedora GNU/Linux (or with fcitx input method). 1036 1037Fedora Core 4 steals the C-SPC key by default for the 'iiimx' program 1038which is the input method for some languages. It blocks Emacs users 1039from using the C-SPC key for 'set-mark-command'. 1040 1041One solutions is to remove the '<Ctrl>space' from the 'Iiimx' file 1042which can be found in the '/usr/lib/X11/app-defaults' directory. 1043However, that requires root access. 1044 1045Another is to specify 'Emacs*useXIM: false' in your X resources. 1046 1047Another is to build Emacs with the '--without-xim' configure option. 1048 1049The same problem happens on any other system if you are using fcitx 1050(Chinese input method) which by default use C-SPC for toggling. If 1051you want to use fcitx with Emacs, you have two choices. Toggle fcitx 1052by another key (e.g. C-\) by modifying ~/.fcitx/config, or be 1053accustomed to use C-@ for 'set-mark-command'. 1054 1055*** Link-time optimization with clang doesn't work on Fedora 20. 1056 1057As of May 2014, Fedora 20 has broken LLVMgold.so plugin support in clang 1058(tested with clang-3.4-6.fc20) - 'clang --print-file-name=LLVMgold.so' 1059prints 'LLVMgold.so' instead of full path to plugin shared library, and 1060'clang -flto' is unable to find the plugin with the following error: 1061 1062/bin/ld: error: /usr/bin/../lib/LLVMgold.so: could not load plugin library: 1063/usr/bin/../lib/LLVMgold.so: cannot open shared object file: No such file 1064or directory 1065 1066The only way to avoid this is to build your own clang from source code 1067repositories, as described at http://clang.llvm.org/get_started.html. 1068 1069*** M-SPC seems to be ignored as input. 1070 1071See if your X server is set up to use this as a command 1072for character composition. 1073 1074*** The S-C-t key combination doesn't get passed to Emacs on X. 1075 1076This happens because some X configurations assign the Ctrl-Shift-t 1077combination the same meaning as the Multi_key. The offending 1078definition is in the file '...lib/X11/locale/iso8859-1/Compose'; there 1079might be other similar combinations which are grabbed by X for similar 1080purposes. 1081 1082We think that this can be countermanded with the 'xmodmap' utility, if 1083you want to be able to bind one of these key sequences within Emacs. 1084 1085*** Under X, C-v and/or other keys don't work. 1086 1087These may have been intercepted by your window manager. 1088See the WM's documentation for how to change this. 1089 1090*** Clicking C-mouse-2 in the scroll bar doesn't split the window. 1091 1092This currently doesn't work with scroll-bar widgets (and we don't know 1093a good way of implementing it with widgets). If Emacs is configured 1094--without-toolkit-scroll-bars, C-mouse-2 on the scroll bar does work. 1095 1096*** Inability to send an Alt-modified key, when Emacs is communicating 1097directly with an X server. 1098 1099If you have tried to bind an Alt-modified key as a command, and it 1100does not work to type the command, the first thing you should check is 1101whether the key is getting through to Emacs. To do this, type C-h c 1102followed by the Alt-modified key. C-h c should say what kind of event 1103it read. If it says it read an Alt-modified key, then make sure you 1104have made the key binding correctly. 1105 1106If C-h c reports an event that doesn't have the Alt modifier, it may 1107be because your X server has no key for the Alt modifier. The X 1108server that comes from MIT does not set up the Alt modifier by default. 1109 1110If your keyboard has keys named Alt, you can enable them as follows: 1111 1112 xmodmap -e 'add mod2 = Alt_L' 1113 xmodmap -e 'add mod2 = Alt_R' 1114 1115If the keyboard has just one key named Alt, then only one of those 1116commands is needed. The modifier 'mod2' is a reasonable choice if you 1117are using an unmodified MIT version of X. Otherwise, choose any 1118modifier bit not otherwise used. 1119 1120If your keyboard does not have keys named Alt, you can use some other 1121keys. Use the keysym command in xmodmap to turn a function key (or 1122some other 'spare' key) into Alt_L or into Alt_R, and then use the 1123commands show above to make them modifier keys. 1124 1125Note that if you have Alt keys but no Meta keys, Emacs translates Alt 1126into Meta. This is because of the great importance of Meta in Emacs. 1127 1128*** Emacs hangs or crashes when a large portion of text is selected or killed. 1129 1130This is caused by a bug in the clipboard management applets (it has 1131been observed in 'klipper' and 'clipit'), which periodically request 1132the X clipboard contents from applications. After a while, Emacs may 1133print a message: 1134 1135 Timed out waiting for property-notify event 1136 1137A workaround is to not use 'klipper'/'clipit'. Upgrading 'klipper' to 1138the one coming with KDE 3.3 or later might solve the problem; if it 1139doesn't, set 'select-active-regions' to 'only' or nil. 1140 1141** Window-manager and toolkit-related problems 1142 1143*** Emacs built with GTK+ toolkit produces corrupted display on HiDPI screen 1144 1145This can happen if you set GDK_SCALE=2 in the environment or in your 1146'.xinitrc' file. (This setting is usually accompanied by 1147GDK_DPI_SCALE=0.5.) Emacs can not support these settings correctly, 1148as it doesn't use GTK+ exclusively. The result is that sometimes 1149widgets like the scroll bar are displayed incorrectly, and frames 1150could be displayed "cropped" to only part of the stuff that should be 1151displayed. 1152 1153The workaround is to explicitly disable these settings when invoking 1154Emacs, for example (from a Posix shell prompt): 1155 1156 $ GDK_SCALE=1 GDK_DPI_SCALE=1 emacs 1157 1158*** Emacs built with GTK+ toolkit can unexpectedly widen frames 1159 1160This resizing takes place when a frame is not wide enough to accommodate 1161its entire menu bar. Typically, it occurs when switching buffers or 1162changing a buffer's major mode and the new mode adds entries to the menu 1163bar. The frame is then widened by the window manager so that the menu 1164bar is fully shown. Subsequently switching to another buffer or 1165changing the buffer's mode will not shrink the frame back to its 1166previous width. The height of the frame remains unaltered. Apparently, 1167the failure is also dependent on the chosen font. 1168 1169The resizing is usually accompanied by console output like 1170 1171Gtk-CRITICAL **: gtk_distribute_natural_allocation: assertion 'extra_space >= 0' failed 1172 1173It's not clear whether the GTK version used has any impact on the 1174occurrence of the failure. So far, the failure has been observed with 1175GTK+ versions 3.4.2, 3.14.5 and 3.18.7. However, another 3.4.2 build 1176does not exhibit the bug. 1177 1178Some window managers (Xfce) apparently work around this failure by 1179cropping the menu bar. With other windows managers, it's possible to 1180shrink the frame manually after the problem occurs, e.g. by dragging the 1181frame's border with the mouse. However, some window managers have been 1182reported to refuse such attempts and snap back to the width needed to 1183show the full menu bar (wmii) or at least cause the screen to flicker 1184during such resizing attempts (i3, IceWM). 1185 1186See also https://debbugs.gnu.org/cgi/bugreport.cgi?bug=15700, 1187https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22000, 1188https://debbugs.gnu.org/cgi/bugreport.cgi?bug=22898 and 1189https://lists.gnu.org/r/emacs-devel/2016-07/msg00154.html. 1190 1191*** Metacity: Resizing Emacs or ALT-Tab causes X to be unresponsive. 1192 1193This happens sometimes when using Metacity. Resizing Emacs or ALT-Tab:bing 1194makes the system unresponsive to the mouse or the keyboard. Killing Emacs 1195or shifting out from X and back again usually cures it (i.e. Ctrl-Alt-F1 1196and then Alt-F7). A bug for it is here: 1197https://bugs.launchpad.net/ubuntu/+source/metacity/+bug/231034. 1198Note that a permanent fix seems to be to disable "assistive technologies". 1199 1200*** Gnome: Emacs receives input directly from the keyboard, bypassing XIM. 1201 1202This seems to happen when gnome-settings-daemon version 2.12 or later 1203is running. If gnome-settings-daemon is not running, Emacs receives 1204input through XIM without any problem. Furthermore, this seems only 1205to happen in *.UTF-8 locales; zh_CN.GB2312 and zh_CN.GBK locales, for 1206example, work fine. A bug report has been filed in the Gnome 1207bugzilla: https://bugzilla.gnome.org/show_bug.cgi?id=357032 1208 1209*** Gnome: GPaste clipboard manager causes erratic behavior of 'yank' 1210 1211The symptom is that 'kill-line' followed by 'yank' often (but not 1212always) doesn't insert the whitespace of the killed and yanked line. 1213 1214The solution is to set the GPaste "trim items" option to OFF. 1215 1216*** Gnome: Navigation from Nautilus to remote files. 1217 1218If you navigate to a file, which belongs to a remote server, in 1219Nautilus via "Open With Emacs" you might not be able to save this file 1220once you have modified it in Emacs. The reasons for the failure can 1221vary, and for some connection methods saving the file might even succeed. 1222 1223If the remote connection in Nautilus uses ssh or sftp, you could 1224mitigate the problem by the following lines in your .emacs file: 1225 1226(dir-locals-set-class-variables 'gvfs '((nil . ((create-lockfiles . nil))))) 1227(dir-locals-set-directory-class (format "/run/user/%d/gvfs" (user-uid)) 'gvfs) 1228 1229A better approach might be to avoid navigation from Nautilus to Emacs 1230for such files, and instead to open the file in Emacs using Tramp 1231remote file name syntax. 1232 1233*** KDE: When running on KDE, colors or fonts are not as specified for Emacs, 1234or messed up. 1235 1236For example, you could see background you set for Emacs only in the 1237empty portions of the Emacs display, while characters have some other 1238background. 1239 1240This happens because KDE's defaults apply its color and font 1241definitions even to applications that weren't compiled for KDE. The 1242solution is to uncheck the "Apply fonts and colors to non-KDE apps" 1243option in Preferences->Look&Feel->Style (KDE 2). In KDE 3, this option 1244is in the "Colors" section, rather than "Style". 1245 1246Alternatively, if you do want the KDE defaults to apply to other 1247applications, but not to Emacs, you could modify the file 'Emacs.ad' 1248(should be in the '/usr/share/apps/kdisplay/app-defaults/' directory) 1249so that it doesn't set the default background and foreground only for 1250Emacs. For example, make sure the following resources are either not 1251present or commented out: 1252 1253 Emacs.default.attributeForeground 1254 Emacs.default.attributeBackground 1255 Emacs*Foreground 1256 Emacs*Background 1257 1258It is also reported that a bug in the gtk-engines-qt engine can cause this if 1259Emacs is compiled with Gtk+. 1260The bug is fixed in version 0.7 or newer of gtk-engines-qt. 1261 1262*** KDE / Plasma 5: Emacs exhausts memory and needs to be killed 1263 1264This problem occurs when large selections contain mixed line endings 1265(i.e. the buffer has LF line endings, but in some parts CRLF is used). 1266The source of the problem is currently under investigation, older 1267versions of Emacs up to 24.5 just hang for a few seconds and then 1268return with the message "Timed out waiting for property-notify event" 1269as described in the previous note. As a workaround, go to the 1270settings dialog for the Clipboard widget and select the option "Ignore 1271Selection". 1272 1273Note: Plasma 5 has replaced the separate klipper process from earlier 1274KDE versions with functionality directly integrated into plasmashell, 1275so even if you've previously did not use klipper this will affect you. 1276Also, all configuration you might have done to klipper is not used by 1277the new Clipboard widget / plasmoid since it uses its own settings. 1278You can hide the Clipboard widget by removing its entry from the 1279system tray settings "Extra Items", but it's not clear if the 1280underlying functionality in plasmashell gets fully disabled as well. 1281At least a restart of plasmashell is required for the clipboard 1282history to be cleared. 1283 1284*** CDE: Frames may cover dialogs they created when using CDE. 1285 1286This can happen if you have "Allow Primary Windows On Top" enabled which 1287seems to be the default in the Common Desktop Environment. 1288To change, go in to "Desktop Controls" -> "Window Style Manager" 1289and uncheck "Allow Primary Windows On Top". 1290 1291*** Xaw3d : When using Xaw3d scroll bars without arrows, the very first mouse 1292click in a scroll bar might be ignored by the scroll bar widget. This 1293is probably a bug in Xaw3d; when Xaw3d is compiled with arrows, the 1294problem disappears. 1295 1296*** Xaw: There are known binary incompatibilities between Xaw, Xaw3d, neXtaw, 1297XawM and the few other derivatives of Xaw. So when you compile with 1298one of these, it may not work to dynamically link with another one. 1299For example, strange problems, such as Emacs exiting when you type 1300"C-x 1", were reported when Emacs compiled with Xaw3d and libXaw was 1301used with neXtaw at run time. 1302 1303The solution is to rebuild Emacs with the toolkit version you actually 1304want to use, or set LD_PRELOAD to preload the same toolkit version you 1305built Emacs with. 1306 1307*** Open Motif: Problems with file dialogs in Emacs built with Open Motif. 1308 1309When Emacs 21 is built with Open Motif 2.1, it can happen that the 1310graphical file dialog boxes do not work properly. The "OK", "Filter" 1311and "Cancel" buttons do not respond to mouse clicks. Dragging the 1312file dialog window usually causes the buttons to work again. 1313 1314As a workaround, you can try building Emacs using Motif or LessTif instead. 1315 1316Another workaround is not to use the mouse to trigger file prompts, 1317but to use the keyboard. This way, you will be prompted for a file in 1318the minibuffer instead of a graphical file dialog. 1319 1320*** LessTif: Problems in Emacs built with LessTif. 1321 1322The problems seem to depend on the version of LessTif and the Motif 1323emulation for which it is set up. 1324 1325Only the Motif 1.2 emulation seems to be stable enough in LessTif. 1326LessTif 0.92-17's Motif 1.2 emulation seems to work okay on FreeBSD. 1327On GNU/Linux systems, lesstif-0.92.6 configured with "./configure 1328--enable-build-12 --enable-default-12" is reported to be the most 1329successful. The binary GNU/Linux package 1330lesstif-devel-0.92.0-1.i386.rpm was reported to have problems with 1331menu placement. 1332 1333On some systems, Emacs occasionally locks up, grabbing all mouse and 1334keyboard events. We don't know what causes these problems; they are 1335not reproducible by Emacs developers. 1336 1337*** Motif: The Motif version of Emacs paints the screen a solid color. 1338 1339This has been observed to result from the following X resource: 1340 1341 Emacs*default.attributeFont: -*-courier-medium-r-*-*-*-140-*-*-*-*-iso8859-* 1342 1343That the resource has this effect indicates a bug in something, but we 1344do not know what. If it is an Emacs bug, we hope someone can 1345explain what the bug is so we can fix it. In the mean time, removing 1346the resource prevents the problem. 1347 1348*** FVWM: Some versions of FVWM incorrectly set the 'sticky' frame parameter. 1349 1350Version 2.6.4 of the FVWM can make a frame sticky (appear on all user 1351desktops) when setting the 'sticky' frame parameter to nil. This may 1352happen without any special user interaction, for example, when Emacs 1353restores a saved desktop. A fix is to install version 2.6.8 of FVWM, 1354see https://debbugs.gnu.org/cgi/bugreport.cgi?bug=31650. 1355 1356** General X problems 1357 1358*** Redisplay using X is much slower than previous Emacs versions. 1359 1360We've noticed that certain X servers draw the text much slower when 1361scroll bars are on the left. We don't know why this happens. If this 1362happens to you, you can work around it by putting the scroll bars 1363on the right (as they were in Emacs 19). 1364 1365Here's how to do this: 1366 1367 (set-scroll-bar-mode 'right) 1368 1369If you're not sure whether (or how much) this problem affects you, 1370try that and see how much difference it makes. To set things back 1371to normal, do 1372 1373 (set-scroll-bar-mode 'left) 1374 1375*** Error messages about undefined colors on X. 1376 1377The messages might say something like this: 1378 1379 Unable to load color "grey95" 1380 1381(typically, in the '*Messages*' buffer), or something like this: 1382 1383 Error while displaying tooltip: (error Undefined color lightyellow) 1384 1385These problems could happen if some other X program has used up too 1386many colors of the X palette, leaving Emacs with insufficient system 1387resources to load all the colors it needs. 1388 1389A solution is to exit the offending X programs before starting Emacs. 1390 1391"undefined color" messages can also occur if the RgbPath entry in the 1392X configuration file is incorrect, or the rgb.txt file is not where 1393X expects to find it. 1394 1395*** Improving performance with slow X connections. 1396 1397There are several ways to improve this performance, any subset of which can 1398be carried out at the same time: 1399 14001) If you don't need X Input Methods (XIM) for entering text in some 1401 language you use, you can improve performance on WAN links by using 1402 the X resource useXIM to turn off use of XIM. This does not affect 1403 the use of Emacs's own input methods, which are part of the Leim 1404 package. 1405 14062) If the connection is very slow, you might also want to consider 1407 switching off scroll bars, menu bar, and tool bar. Adding the 1408 following forms to your .emacs file will accomplish that, but only 1409 after the initial frame is displayed: 1410 1411 (scroll-bar-mode -1) 1412 (menu-bar-mode -1) 1413 (tool-bar-mode -1) 1414 1415 For still quicker startup, put these X resources in your 1416 .Xresources or .Xdefaults file: 1417 1418 Emacs.verticalScrollBars: off 1419 Emacs.menuBar: off 1420 Emacs.toolBar: off 1421 14223) Use ssh to forward the X connection, and enable compression on this 1423 forwarded X connection (ssh -XC remotehostname emacs ...). 1424 14254) Use lbxproxy on the remote end of the connection. This is an interface 1426 to the low bandwidth X extension in most modern X servers, which 1427 improves performance dramatically, at the slight expense of correctness 1428 of the X protocol. lbxproxy achieves the performance gain by grouping 1429 several X requests in one TCP packet and sending them off together, 1430 instead of requiring a round-trip for each X request in a separate 1431 packet. The switches that seem to work best for emacs are: 1432 -noatomsfile -nowinattr -cheaterrors -cheatevents 1433 Note that the -nograbcmap option is known to cause problems. 1434 For more about lbxproxy, see: 1435 http://www.x.org/archive/X11R6.8.0/doc/lbxproxy.1.html 1436 14375) If copying and killing is slow, try to disable the interaction with the 1438 native system's clipboard by adding these lines to your .emacs file: 1439 (setq interprogram-cut-function nil) 1440 (setq interprogram-paste-function nil) 1441 1442*** Emacs gives the error, Couldn't find per display information. 1443 1444This can result if the X server runs out of memory because Emacs uses 1445a large number of fonts. On systems where this happens, C-h h is 1446likely to cause it. 1447 1448We do not know of a way to prevent the problem. 1449 1450*** Emacs does not notice when you release the mouse. 1451 1452There are reports that this happened with (some) Microsoft mice and 1453that replacing the mouse made it stop. 1454 1455*** You can't select from submenus (in the X toolkit version). 1456 1457On certain systems, mouse-tracking and selection in top-level menus 1458works properly with the X toolkit, but neither of them works when you 1459bring up a submenu (such as Bookmarks or Compare or Apply Patch, in 1460the Files menu). 1461 1462This works on most systems. There is speculation that the failure is 1463due to bugs in old versions of X toolkit libraries, but no one really 1464knows. If someone debugs this and finds the precise cause, perhaps a 1465workaround can be found. 1466 1467*** An error message such as 'X protocol error: BadMatch (invalid 1468parameter attributes) on protocol request 93'. 1469 1470This comes from having an invalid X resource, such as 1471 emacs*Cursor: black 1472(which is invalid because it specifies a color name for something 1473that isn't a color.) 1474 1475The fix is to correct your X resources. 1476 1477*** Slow startup on X11R6 with X windows. 1478 1479If Emacs takes two minutes to start up on X11R6, see if your X 1480resources specify any Adobe fonts. That causes the type-1 font 1481renderer to start up, even if the font you asked for is not a type-1 1482font. 1483 1484One way to avoid this problem is to eliminate the type-1 fonts from 1485your font path, like this: 1486 1487 xset -fp /usr/X11R6/lib/X11/fonts/Type1/ 1488 1489*** Pull-down menus appear in the wrong place, in the toolkit version of Emacs. 1490 1491An X resource of this form can cause the problem: 1492 1493 Emacs*geometry: 80x55+0+0 1494 1495This resource is supposed to apply, and does apply, to the menus 1496individually as well as to Emacs frames. If that is not what you 1497want, rewrite the resource. 1498 1499To check thoroughly for such resource specifications, use 'xrdb 1500-query' to see what resources the X server records, and also look at 1501the user's ~/.Xdefaults and ~/.Xdefaults-* files. 1502 1503*** Emacs running under X Window System does not handle mouse clicks. 1504*** 'emacs -geometry 80x20' finds a file named '80x20'. 1505 1506One cause of such problems is having (setq term-file-prefix nil) in 1507your .emacs file. Another cause is a bad value of EMACSLOADPATH in 1508the environment. 1509 1510*** X doesn't work if DISPLAY uses a hostname. 1511 1512People have reported kernel bugs in certain systems that cause Emacs 1513not to work with X if DISPLAY is set using a host name. But 1514the problem does not occur if DISPLAY is set to 'unix:0.0'. I think 1515the bug has to do with SIGIO or FIONREAD. 1516 1517You may be able to compensate for the bug by doing (set-input-mode nil nil). 1518However, that has the disadvantage of turning off interrupts, so that 1519you are unable to quit out of a Lisp program by typing C-g. 1520 1521*** Prevent double pastes in X 1522 1523The problem: a region, such as a command, is pasted twice when you copy 1524it with your mouse from GNU Emacs to an xterm or an RXVT shell in X. 1525The solution: try the following in your X configuration file, 1526/etc/X11/xorg.conf This should enable both PS/2 and USB mice for 1527single copies. You do not need any other drivers or options. 1528 1529 Section "InputDevice" 1530 Identifier "Generic Mouse" 1531 Driver "mousedev" 1532 Option "Device" "/dev/input/mice" 1533 EndSection 1534 1535*** Emacs is slow to exit in X 1536 1537After you use e.g. C-x C-c to exit, it takes many seconds before the 1538Emacs window disappears. If Emacs was started from a terminal, you 1539see the message: 1540 1541 Error saving to X clipboard manager. 1542 If the problem persists, set 'x-select-enable-clipboard-manager' to nil. 1543 1544As the message suggests, this problem occurs when Emacs thinks you 1545have a clipboard manager program running, but has trouble contacting it. 1546If you don't want to use a clipboard manager, you can set the 1547suggested variable. Or you can make Emacs not wait so long by 1548reducing the value of 'x-selection-timeout', either in .emacs or with 1549X resources. 1550 1551Sometimes this problem is due to a bug in your clipboard manager. 1552Updating to the latest version of the manager can help. 1553For example, in the Xfce 4.8 desktop environment, the clipboard 1554manager in versions of xfce4-settings-helper before 4.8.2 is buggy; 1555https://bugzilla.xfce.org/show_bug.cgi?id=7588 . 1556 1557*** Warning messages when running in Ubuntu 1558 1559When you start Emacs you may see something like this: 1560 1561(emacs:2286): LIBDBUSMENU-GTK-CRITICAL **: watch_submenu: assertion 1562'GTK_IS_MENU_SHELL(menu)' failed 1563 1564This happens if the Emacs binary has been renamed. The cause is the Ubuntu 1565appmenu concept. It tries to track Emacs menus and show them in the top 1566panel, instead of in each Emacs window. This is not properly implemented, 1567so it fails for Emacs. The order of menus is wrong, and things like copy/paste 1568that depend on what state Emacs is in are usually wrong (i.e. paste disabled 1569even if you should be able to paste, and similar). 1570 1571You can get back menus on each frame by starting emacs like this: 1572% env UBUNTU_MENUPROXY= emacs 1573 1574* Runtime problems on character terminals 1575 1576** The meta key does not work on xterm. 1577 1578Typing M-x rings the terminal bell, and inserts a string like ";120~". 1579For recent xterm versions (>= 216), Emacs uses xterm's modifyOtherKeys 1580feature to generate strings for key combinations that are not 1581otherwise usable. One circumstance in which this can cause problems 1582is if you have specified the X resource 1583 1584 xterm*VT100.Translations 1585 1586to contain translations that use the meta key. Then xterm will not 1587use meta in modified function-keys, which confuses Emacs. To fix 1588this, you can remove the X resource or put this in your init file: 1589 1590 (xterm-remove-modify-other-keys) 1591 1592** Emacs spontaneously displays "I-search: " at the bottom of the screen. 1593 1594This means that Control-S/Control-Q (XON/XOFF) "flow control" is being 1595used. C-s/C-q flow control is bad for Emacs editors because it takes 1596away C-s and C-q as user commands. Since editors do not output long 1597streams of text without user commands, there is no need for a 1598user-issuable "stop output" command in an editor; therefore, a 1599properly designed flow control mechanism would transmit all possible 1600input characters without interference. Designing such a mechanism is 1601easy, for a person with at least half a brain. 1602 1603There are three possible reasons why flow control could be taking place: 1604 1605 1) Terminal has not been told to disable flow control 1606 2) Insufficient padding for the terminal in use 1607 3) Some sort of terminal concentrator or line switch is responsible 1608 1609First of all, many terminals have a set-up mode which controls whether 1610they generate XON/XOFF flow control characters. This must be set to 1611"no XON/XOFF" in order for Emacs to work. (For example, on a VT220 1612you may select "No XOFF" in the setup menu.) Sometimes there is an 1613escape sequence that the computer can send to turn flow control off 1614and on. If so, perhaps the termcap 'ti' string should turn flow 1615control off, and the 'te' string should turn it on. 1616 1617Once the terminal has been told "no flow control", you may find it 1618needs more padding. The amount of padding Emacs sends is controlled 1619by the termcap entry for the terminal in use, and by the output baud 1620rate as known by the kernel. The shell command 'stty' will print 1621your output baud rate; 'stty' with suitable arguments will set it if 1622it is wrong. Setting to a higher speed causes increased padding. If 1623the results are wrong for the correct speed, there is probably a 1624problem in the termcap entry. You must speak to a local Unix wizard 1625to fix this. Perhaps you are just using the wrong terminal type. 1626 1627For terminals that lack a "no flow control" mode, sometimes just 1628giving lots of padding will prevent actual generation of flow control 1629codes. You might as well try it. 1630 1631If you are really unlucky, your terminal is connected to the computer 1632through a concentrator which sends XON/XOFF flow control to the 1633computer, or it insists on sending flow control itself no matter how 1634much padding you give it. Unless you can figure out how to turn flow 1635control off on this concentrator (again, refer to your local wizard), 1636you are screwed! You should have the terminal or concentrator 1637replaced with a properly designed one. In the mean time, some drastic 1638measures can make Emacs semi-work. 1639 1640You can make Emacs ignore C-s and C-q and let the operating system 1641handle them. To do this on a per-session basis, just type M-x 1642enable-flow-control RET. You will see a message that C-\ and C-^ are 1643now translated to C-s and C-q. (Use the same command M-x 1644enable-flow-control to turn *off* this special mode. It toggles flow 1645control handling.) 1646 1647If C-\ and C-^ are inconvenient for you (for example, if one of them 1648is the escape character of your terminal concentrator), you can choose 1649other characters by setting the variables flow-control-c-s-replacement 1650and flow-control-c-q-replacement. But choose carefully, since all 1651other control characters are already used by emacs. 1652 1653IMPORTANT: if you type C-s by accident while flow control is enabled, 1654Emacs output will freeze, and you will have to remember to type C-q in 1655order to continue. 1656 1657If you work in an environment where a majority of terminals of a 1658certain type are flow control hobbled, you can use the function 1659'enable-flow-control-on' to turn on this flow control avoidance scheme 1660automatically. Here is an example: 1661 1662(enable-flow-control-on "vt200" "vt300" "vt101" "vt131") 1663 1664If this isn't quite correct (e.g. you have a mixture of flow-control hobbled 1665and good vt200 terminals), you can still run enable-flow-control 1666manually. 1667 1668I have no intention of ever redesigning the Emacs command set for the 1669assumption that terminals use C-s/C-q flow control. XON/XOFF flow 1670control technique is a bad design, and terminals that need it are bad 1671merchandise and should not be purchased. Now that X is becoming 1672widespread, XON/XOFF seems to be on the way out. If you can get some 1673use out of GNU Emacs on inferior terminals, more power to you, but I 1674will not make Emacs worse for properly designed systems for the sake 1675of inferior systems. 1676 1677** Control-S and Control-Q commands are ignored completely. 1678 1679For some reason, your system is using brain-damaged C-s/C-q flow 1680control despite Emacs's attempts to turn it off. Perhaps your 1681terminal is connected to the computer through a concentrator 1682that wants to use flow control. 1683 1684You should first try to tell the concentrator not to use flow control. 1685If you succeed in this, try making the terminal work without 1686flow control, as described in the preceding section. 1687 1688If that line of approach is not successful, map some other characters 1689into C-s and C-q using keyboard-translate-table. The example above 1690shows how to do this with C-^ and C-\. 1691 1692** Screen is updated wrong, but only on one kind of terminal. 1693 1694This could mean that the termcap entry you are using for that 1695terminal is wrong, or it could mean that Emacs has a bug handling 1696the combination of features specified for that terminal. 1697 1698The first step in tracking this down is to record what characters 1699Emacs is sending to the terminal. Execute the Lisp expression 1700(open-termscript "./emacs-script") to make Emacs write all 1701terminal output into the file ~/emacs-script as well; then do 1702what makes the screen update wrong, and look at the file 1703and decode the characters using the manual for the terminal. 1704There are several possibilities: 1705 17061) The characters sent are correct, according to the terminal manual. 1707 1708In this case, there is no obvious bug in Emacs, and most likely you 1709need more padding, or possibly the terminal manual is wrong. 1710 17112) The characters sent are incorrect, due to an obscure aspect 1712 of the terminal behavior not described in an obvious way by termcap. 1713 1714This case is hard. It will be necessary to think of a way for 1715Emacs to distinguish between terminals with this kind of behavior 1716and other terminals that behave subtly differently but are 1717classified the same by termcap; or else find an algorithm for 1718Emacs to use that avoids the difference. Such changes must be 1719tested on many kinds of terminals. 1720 17213) The termcap entry is wrong. 1722 1723See the file etc/TERMS for information on changes 1724that are known to be needed in commonly used termcap entries 1725for certain terminals. 1726 17274) The characters sent are incorrect, and clearly cannot be 1728 right for any terminal with the termcap entry you were using. 1729 1730This is unambiguously an Emacs bug, and can probably be fixed 1731in termcap.c, tparam.c, term.c, scroll.c, cm.c or dispnew.c. 1732 1733** Control-S and Control-Q commands are ignored completely on a net connection. 1734 1735Some versions of rlogin (and possibly telnet) do not pass flow 1736control characters to the remote system to which they connect. 1737On such systems, emacs on the remote system cannot disable flow 1738control on the local system. Sometimes 'rlogin -8' will avoid this problem. 1739 1740One way to cure this is to disable flow control on the local host 1741(the one running rlogin, not the one running rlogind) using the 1742stty command, before starting the rlogin process. On many systems, 1743"stty start u stop u" will do this. On some systems, use 1744"stty -ixon" instead. 1745 1746Some versions of tcsh will prevent even this from working. One way 1747around this is to start another shell before starting rlogin, and 1748issue the stty command to disable flow control from that shell. 1749 1750If none of these methods work, the best solution is to type 1751M-x enable-flow-control at the beginning of your emacs session, or 1752if you expect the problem to continue, add a line such as the 1753following to your .emacs (on the host running rlogind): 1754 1755(enable-flow-control-on "vt200" "vt300" "vt101" "vt131") 1756 1757See the entry about spontaneous display of I-search (above) for more info. 1758 1759** Output from Control-V is slow. 1760 1761On many bit-map terminals, scrolling operations are fairly slow. 1762Often the termcap entry for the type of terminal in use fails 1763to inform Emacs of this. The two lines at the bottom of the screen 1764before a Control-V command are supposed to appear at the top after 1765the Control-V command. If Emacs thinks scrolling the lines is fast, 1766it will scroll them to the top of the screen. 1767 1768If scrolling is slow but Emacs thinks it is fast, the usual reason is 1769that the termcap entry for the terminal you are using does not 1770specify any padding time for the 'al' and 'dl' strings. Emacs 1771concludes that these operations take only as much time as it takes to 1772send the commands at whatever line speed you are using. You must 1773fix the termcap entry to specify, for the 'al' and 'dl', as much 1774time as the operations really take. 1775 1776Currently Emacs thinks in terms of serial lines which send characters 1777at a fixed rate, so that any operation which takes time for the 1778terminal to execute must also be padded. With bit-map terminals 1779operated across networks, often the network provides some sort of 1780flow control so that padding is never needed no matter how slow 1781an operation is. You must still specify a padding time if you want 1782Emacs to realize that the operation takes a long time. This will 1783cause padding characters to be sent unnecessarily, but they do 1784not really cost much. They will be transmitted while the scrolling 1785is happening and then discarded quickly by the terminal. 1786 1787Most bit-map terminals provide commands for inserting or deleting 1788multiple lines at once. Define the 'AL' and 'DL' strings in the 1789termcap entry to say how to do these things, and you will have 1790fast output without wasted padding characters. These strings should 1791each contain a single %-spec saying how to send the number of lines 1792to be scrolled. These %-specs are like those in the termcap 1793'cm' string. 1794 1795You should also define the 'IC' and 'DC' strings if your terminal 1796has a command to insert or delete multiple characters. These 1797take the number of positions to insert or delete as an argument. 1798 1799A 'cs' string to set the scrolling region will reduce the amount 1800of motion you see on the screen when part of the screen is scrolled. 1801 1802** You type Control-H (Backspace) expecting to delete characters. 1803 1804Put 'stty dec' in your .login file and your problems will disappear 1805after a day or two. 1806 1807The choice of Backspace for erasure was based on confusion, caused by 1808the fact that backspacing causes erasure (later, when you type another 1809character) on most display terminals. But it is a mistake. Deletion 1810of text is not the same thing as backspacing followed by failure to 1811overprint. I do not wish to propagate this confusion by conforming 1812to it. 1813 1814For this reason, I believe 'stty dec' is the right mode to use, 1815and I have designed Emacs to go with that. If there were a thousand 1816other control characters, I would define Control-h to delete as well; 1817but there are not very many other control characters, and I think 1818that providing the most mnemonic possible Help character is more 1819important than adapting to people who don't use 'stty dec'. 1820 1821If you are obstinate about confusing buggy overprinting with deletion, 1822you can redefine Backspace in your .emacs file: 1823 (global-set-key "\b" 'delete-backward-char) 1824You can probably access help-command via f1. 1825 1826** Colors are not available on a tty or in xterm. 1827 1828Emacs 21 supports colors on character terminals and terminal 1829emulators, but this support relies on the terminfo or termcap database 1830entry to specify that the display supports color. Emacs looks at the 1831"Co" capability for the terminal to find out how many colors are 1832supported; it should be non-zero to activate the color support within 1833Emacs. (Most color terminals support 8 or 16 colors.) If your system 1834uses terminfo, the name of the capability equivalent to "Co" is 1835"colors". 1836 1837In addition to the "Co" capability, Emacs needs the "op" (for 1838"original pair") capability, which tells how to switch the terminal 1839back to the default foreground and background colors. Emacs will not 1840use colors if this capability is not defined. If your terminal entry 1841doesn't provide such a capability, try using the ANSI standard escape 1842sequence \E[00m (that is, define a new termcap/terminfo entry and make 1843it use your current terminal's entry plus \E[00m for the "op" 1844capability). 1845 1846Finally, the "NC" capability (terminfo name: "ncv") tells Emacs which 1847attributes cannot be used with colors. Setting this capability 1848incorrectly might have the effect of disabling colors; try setting 1849this capability to '0' (zero) and see if that helps. 1850 1851Emacs uses the database entry for the terminal whose name is the value 1852of the environment variable TERM. With 'xterm', a common terminal 1853entry that supports color is 'xterm-color', so setting TERM's value to 1854'xterm-color' might activate the color support on an xterm-compatible 1855emulator. 1856 1857Beginning with version 22.1, Emacs supports the --color command-line 1858option which may be used to force Emacs to use one of a few popular 1859modes for getting colors on a tty. For example, --color=ansi8 sets up 1860for using the ANSI-standard escape sequences that support 8 colors. 1861 1862Some modes do not use colors unless you turn on the Font-lock mode. 1863Some people have long ago set their '~/.emacs' files to turn on 1864Font-lock on X only, so they won't see colors on a tty. The 1865recommended way of turning on Font-lock is by typing "M-x 1866global-font-lock-mode RET" or by customizing the variable 1867'global-font-lock-mode'. 1868 1869** Unexpected characters inserted into the buffer when you start Emacs. 1870See e.g. <URL:https://debbugs.gnu.org/11129> 1871 1872This can happen when you start Emacs in -nw mode in an Xterm. 1873For example, in the *scratch* buffer, you might see something like: 1874 1875 0;276;0c 1876 1877This is more likely to happen if you are using Emacs over a slow 1878connection, and begin typing before Emacs is ready to respond. 1879 1880This occurs when Emacs tries to query the terminal to see what 1881capabilities it supports, and gets confused by the answer. 1882To avoid it, set xterm-extra-capabilities to a value other than 1883'check' (the default). See that variable's documentation (in 1884term/xterm.el) for more details. 1885 1886* Runtime problems specific to individual Unix variants 1887 1888** GNU/Linux 1889 1890*** GNU/Linux: profiler-report outputs nothing. 1891 1892A few versions of the Linux kernel have timer bugs that break CPU 1893profiling; see Bug#34235. To fix the problem, upgrade to one of the 1894kernel versions 4.14.97, 4.19.19, or 4.20.6, or later. 1895 1896*** GNU/Linux: Process output is corrupted. 1897 1898There is a bug in Linux kernel 2.6.10 PTYs that can cause emacs to 1899read corrupted process output. 1900 1901*** GNU/Linux: Remote access to CVS with SSH causes file corruption. 1902 1903If you access a remote CVS repository via SSH, files may be corrupted 1904due to bad interaction between CVS, SSH, and libc. 1905 1906To fix the problem, save the following script into a file, make it 1907executable, and set CVS_RSH environment variable to the file name of 1908the script: 1909 1910#!/bin/bash 1911exec 2> >(exec cat >&2 2>/dev/null) 1912exec ssh "$@" 1913 1914*** GNU/Linux: Truncated svn annotate output with SSH. 1915https://debbugs.gnu.org/7791 1916 1917The symptoms are: you are accessing a svn repository over SSH. 1918You use vc-annotate on a large (several thousand line) file, and the 1919result is truncated around the 1000 line mark. It works fine with 1920other access methods (e.g. http), or from outside Emacs. 1921 1922This may be a similar libc/SSH issue to the one mentioned above for CVS. 1923A similar workaround seems to be effective: create a script with the 1924same contents as the one used above for CVS_RSH, and set the SVN_SSH 1925environment variable to point to it. 1926 1927*** GNU/Linux: After upgrading to a newer version of Emacs, 1928the Meta key stops working. 1929 1930This was reported to happen on a GNU/Linux system distributed by 1931Mandrake. The reason is that the previous version of Emacs was 1932modified by Mandrake to make the Alt key act as the Meta key, on a 1933keyboard where the Windows key is the one which produces the Meta 1934modifier. A user who started using a newer version of Emacs, which 1935was not hacked by Mandrake, expected the Alt key to continue to act as 1936Meta, and was astonished when that didn't happen. 1937 1938The solution is to find out what key on your keyboard produces the Meta 1939modifier, and use that key instead. Try all of the keys to the left 1940and to the right of the space bar, together with the 'x' key, and see 1941which combination produces "M-x" in the echo area. You can also use 1942the 'xmodmap' utility to show all the keys which produce a Meta 1943modifier: 1944 1945 xmodmap -pk | grep -Ei "meta|alt" 1946 1947A more convenient way of finding out which keys produce a Meta modifier 1948is to use the 'xkbprint' utility, if it's available on your system: 1949 1950 xkbprint 0:0 /tmp/k.ps 1951 1952This produces a PostScript file '/tmp/k.ps' with a picture of your 1953keyboard; printing that file on a PostScript printer will show what 1954keys can serve as Meta. 1955 1956The 'xkeycaps' also shows a visual representation of the current 1957keyboard settings. It also allows to modify them. 1958 1959*** GNU/Linux: slow startup on Linux-based GNU systems. 1960 1961People using systems based on the Linux kernel sometimes report that 1962startup takes 10 to 15 seconds longer than 'usual'. 1963 1964This is because Emacs looks up the host name when it starts. 1965Normally, this takes negligible time; the extra delay is due to 1966improper system configuration. This problem can occur for both 1967networked and non-networked machines. 1968 1969Here is how to fix the configuration. It requires being root. 1970 1971**** Networked Case. 1972 1973First, make sure the files '/etc/hosts' and '/etc/host.conf' both 1974exist. The first line in the '/etc/hosts' file should look like this 1975(replace HOSTNAME with your host name): 1976 1977 127.0.0.1 HOSTNAME 1978 1979Also make sure that the '/etc/host.conf' files contains the following 1980lines: 1981 1982 order hosts, bind 1983 multi on 1984 1985Any changes, permanent and temporary, to the host name should be 1986indicated in the '/etc/hosts' file, since it acts a limited local 1987database of addresses and names (e.g., some SLIP connections 1988dynamically allocate ip addresses). 1989 1990**** Non-Networked Case. 1991 1992The solution described in the networked case applies here as well. 1993However, if you never intend to network your machine, you can use a 1994simpler solution: create an empty '/etc/host.conf' file. The command 1995'touch /etc/host.conf' suffices to create the file. The '/etc/hosts' 1996file is not necessary with this approach. 1997 1998*** GNU/Linux: Emacs on a tty switches the cursor to large blinking block. 1999 2000This was reported to happen on some GNU/Linux systems which use 2001ncurses version 5.0, but could be relevant for other versions as well. 2002These versions of ncurses come with a 'linux' terminfo entry, where 2003the "cvvis" capability (termcap "vs") is defined as "\E[?25h\E[?8c" 2004(show cursor, change size). This escape sequence switches on a 2005blinking hardware text-mode cursor whose size is a full character 2006cell. This blinking cannot be stopped, since a hardware cursor 2007always blinks. 2008 2009A work-around is to redefine the "cvvis" capability so that it 2010enables a *software* cursor. The software cursor works by inverting 2011the colors of the character at point, so what you see is a block 2012cursor that doesn't blink. For this to work, you need to redefine 2013the "cnorm" capability as well, so that it operates on the software 2014cursor instead of the hardware cursor. 2015 2016To this end, run "infocmp linux > linux-term", edit the file 2017'linux-term' to make both the "cnorm" and "cvvis" capabilities send 2018the sequence "\E[?25h\E[?17;0;64c", and then run "tic linux-term" to 2019produce a modified terminfo entry. 2020 2021Alternatively, if you want a blinking underscore as your Emacs cursor, 2022set the 'visible-cursor' variable to nil in your ~/.emacs: 2023 (setq visible-cursor nil) 2024 2025Still other way is to change the "cvvis" capability to send the 2026"\E[?25h\E[?0c" command. 2027 2028** FreeBSD 2029 2030*** FreeBSD: Getting a Meta key on the console. 2031 2032By default, neither Alt nor any other key acts as a Meta key on 2033FreeBSD, but this can be changed using kbdcontrol(1). Dump the 2034current keymap to a file with the command 2035 2036 $ kbdcontrol -d >emacs.kbd 2037 2038Edit emacs.kbd, and give the key you want to be the Meta key the 2039definition 'meta'. For instance, if your keyboard has a "Windows" 2040key with scan code 105, change the line for scan code 105 in emacs.kbd 2041to look like this 2042 2043 105 meta meta meta meta meta meta meta meta O 2044 2045to make the Windows key the Meta key. Load the new keymap with 2046 2047 $ kbdcontrol -l emacs.kbd 2048 2049** HP-UX 2050 2051*** HP/UX : Shell mode gives the message, "`tty`: Ambiguous". 2052 2053christos@theory.tn.cornell.edu says: 2054 2055The problem is that in your .cshrc you have something that tries to 2056execute 'tty'. If you are not running the shell on a real tty then 2057tty will print "not a tty". Csh expects one word in some places, 2058but tty is giving it back 3. 2059 2060The solution is to add a pair of quotes around `tty` to make it a single 2061word: 2062 2063if (`tty` == "/dev/console") 2064 2065should be changed to: 2066 2067if ("`tty`" == "/dev/console") 2068 2069Even better, move things that set up terminal sections out of .cshrc 2070and into .login. 2071 2072*** HP/UX: 'Pid xxx killed due to text modification or page I/O error'. 2073 2074On HP/UX, you can get that error when the Emacs executable is on an NFS 2075file system. HP/UX responds this way if it tries to swap in a page and 2076does not get a response from the server within a timeout whose default 2077value is just ten seconds. 2078 2079If this happens to you, extend the timeout period. 2080 2081*** HP/UX: The right Alt key works wrong on German HP keyboards (and perhaps 2082other non-English HP keyboards too). 2083 2084This is because HP-UX defines the modifiers wrong in X. Here is a 2085shell script to fix the problem; be sure that it is run after VUE 2086configures the X server. 2087 2088 xmodmap 2> /dev/null - << EOF 2089 keysym Alt_L = Meta_L 2090 keysym Alt_R = Meta_R 2091 EOF 2092 2093 xmodmap - << EOF 2094 clear mod1 2095 keysym Mode_switch = NoSymbol 2096 add mod1 = Meta_L 2097 keysym Meta_R = Mode_switch 2098 add mod2 = Mode_switch 2099 EOF 2100 2101*** HP/UX: Emacs does not recognize the AltGr key. 2102 2103To fix this, set up a file ~/.dt/sessions/sessionetc with executable 2104rights, containing this text: 2105 2106-------------------------------- 2107xmodmap 2> /dev/null - << EOF 2108keysym Alt_L = Meta_L 2109keysym Alt_R = Meta_R 2110EOF 2111 2112xmodmap - << EOF 2113clear mod1 2114keysym Mode_switch = NoSymbol 2115add mod1 = Meta_L 2116keysym Meta_R = Mode_switch 2117add mod2 = Mode_switch 2118EOF 2119-------------------------------- 2120 2121*** HP/UX 11.0: Emacs makes HP/UX 11.0 crash. 2122 2123This is a bug in HPUX; HPUX patch PHKL_16260 is said to fix it. 2124 2125** AIX 2126 2127*** AIX: Trouble using ptys. 2128 2129People often install the pty devices on AIX incorrectly. 2130Use 'smit pty' to reinstall them properly. 2131 2132*** AIXterm: Your Delete key sends a Backspace to the terminal. 2133 2134The solution is to include in your .Xdefaults the lines: 2135 2136 *aixterm.Translations: #override <Key>BackSpace: string(0x7f) 2137 aixterm*ttyModes: erase ^? 2138 2139This makes your Backspace key send DEL (ASCII 127). 2140 2141*** AIX: If linking fails because libXbsd isn't found, check if you 2142are compiling with the system's 'cc' and CFLAGS containing '-O5'. If 2143so, you have hit a compiler bug. Please make sure to re-configure 2144Emacs so that it isn't compiled with '-O5'. 2145 2146*** AIX 4.3.x or 4.4: Compiling fails. 2147 2148This could happen if you use /bin/c89 as your compiler, instead of 2149the default 'cc'. /bin/c89 treats certain warnings, such as benign 2150redefinitions of macros, as errors, and fails the build. A solution 2151is to use the default compiler 'cc'. 2152 2153*** AIX 4: Some programs fail when run in a Shell buffer 2154with an error message like No terminfo entry for "unknown". 2155 2156On AIX, many terminal type definitions are not installed by default. 2157'unknown' is one of them. Install the "Special Generic Terminal 2158Definitions" to make them defined. 2159 2160** Solaris 2161 2162We list bugs in current versions here. See also the section on legacy 2163systems. 2164 2165*** On Solaris 10, Emacs crashes during the build process. 2166This was reported for Emacs 25.2 on i386-pc-solaris2.10 with Sun 2167Studio 12 (Sun C 5.9) and with Oracle Developer Studio 12.6 (Sun C 21685.15), and intermittently for sparc-sun-solaris2.10 with Oracle 2169Developer Studio 12.5 (Sun C 5.14). Disabling compiler optimization 2170seems to fix the bug, as does upgrading the Solaris 10 operating 2171system to Update 11. The cause of the bug is unknown: it may be that 2172Emacs's archaic memory-allocation scheme is not compatible with 2173slightly-older versions of Solaris and/or Oracle Studio, or it may be 2174something else. Since the cause is not known, possibly the bug is 2175still present in newer versions of Emacs, Oracle Studio, and/or 2176Solaris. See Bug#26638. 2177 2178*** On Solaris, C-x doesn't get through to Emacs when you use the console. 2179 2180This is a Solaris feature (at least on Intel x86 cpus). Type C-r 2181C-r C-t, to toggle whether C-x gets through to Emacs. 2182 2183*** Problem with remote X server on Suns. 2184 2185On a Sun, running Emacs on one machine with the X server on another 2186may not work if you have used the unshared system libraries. This 2187is because the unshared libraries fail to use YP for host name lookup. 2188As a result, the host name you specify may not be recognized. 2189 2190*** Solaris 2.6: Emacs crashes with SIGBUS or SIGSEGV on Solaris after you delete a frame. 2191 2192We suspect that this is a bug in the X libraries provided by 2193Sun. There is a report that one of these patches fixes the bug and 2194makes the problem stop: 2195 2196105216-01 105393-01 105518-01 105621-01 105665-01 105615-02 105216-02 2197105667-01 105401-08 105615-03 105621-02 105686-02 105736-01 105755-03 2198106033-01 105379-01 105786-01 105181-04 105379-03 105786-04 105845-01 2199105284-05 105669-02 105837-01 105837-02 105558-01 106125-02 105407-01 2200 2201Another person using a newer system (kernel patch level Generic_105181-06) 2202suspects that the bug was fixed by one of these more recent patches: 2203 2204106040-07 SunOS 5.6: X Input & Output Method patch 2205106222-01 OpenWindows 3.6: filemgr (ff.core) fixes 2206105284-12 Motif 1.2.7: sparc Runtime library patch 2207 2208*** Solaris 7 or 8: Emacs reports a BadAtom error (from X) 2209 2210This happens when Emacs was built on some other version of Solaris. 2211Rebuild it on Solaris 8. 2212 2213*** When using M-x dbx with the SparcWorks debugger, the 'up' and 'down' 2214commands do not move the arrow in Emacs. 2215 2216You can fix this by adding the following line to '~/.dbxinit': 2217 2218 dbxenv output_short_file_name off 2219 2220*** On Solaris, CTRL-t is ignored by Emacs when you use 2221the fr.ISO-8859-15 locale (and maybe other related locales). 2222 2223You can fix this by editing the file: 2224 2225 /usr/openwin/lib/locale/iso8859-15/Compose 2226 2227Near the bottom there is a line that reads: 2228 2229 Ctrl<t> <quotedbl> <Y> : "\276" threequarters 2230 2231while it should read: 2232 2233 Ctrl<T> <quotedbl> <Y> : "\276" threequarters 2234 2235Note the lower case <t>. Changing this line should make C-t work. 2236 2237*** On Solaris, Emacs fails to set menu-bar-update-hook on startup, with error 2238"Error in menu-bar-update-hook: (error Point before start of properties)". 2239This seems to be a GCC optimization bug that occurs for GCC 4.1.2 (-g 2240and -g -O2) and GCC 4.2.3 (-g -O and -g -O2). You can fix this by 2241compiling with GCC 4.2.3 or CC 5.7, with no optimizations. 2242 2243* Runtime problems specific to MS-Windows 2244 2245** Emacs on Windows 9X requires UNICOWS.DLL 2246 2247If that DLL is not available, Emacs will display an error dialog 2248stating its absence, and refuse to run. 2249 2250This is because Emacs 24.4 and later uses functions whose non-stub 2251implementation is only available in UNICOWS.DLL, which implements the 2252Microsoft Layer for Unicode on Windows 9X, or "MSLU". This article on 2253MSDN: 2254 2255 http://msdn.microsoft.com/en-us/goglobal/bb688166.aspx 2256 2257includes a short description of MSLU and a link where it can be 2258downloaded. 2259 2260** Emacs refuses to start on Windows 9X because ctime64 function is missing 2261 2262This is a sign that Emacs was compiled with MinGW runtime version 22634.0.x or later. These versions of runtime call in their startup code 2264the ctime64 function, which does not exist in MSVCRT.DLL, the C 2265runtime shared library, distributed with Windows 9X. 2266 2267A workaround is to build Emacs with MinGW runtime 3.x (the latest 2268version is 3.20). 2269 2270** addpm fails to run on Windows NT4, complaining about Shell32.dll 2271 2272This is likely to happen because Shell32.dll shipped with NT4 lacks 2273the updates required by Emacs. Installing Internet Explorer 4 solves 2274the problem. Note that it is NOT enough to install IE6, because doing 2275so will not install the Shell32.dll update. 2276 2277** A few seconds delay is seen at startup and for many file operations 2278 2279This happens when the Net Logon service is enabled. During Emacs 2280startup, this service issues many DNS requests looking up for the 2281Windows Domain Controller. When Emacs accesses files on networked 2282drives, it automatically logs on the user into those drives, which 2283again causes delays when Net Logon is running. 2284 2285The solution seems to be to disable Net Logon with this command typed 2286at the Windows shell prompt: 2287 2288 net stop netlogon 2289 2290To start the service again, type "net start netlogon". (You can also 2291stop and start the service from the Computer Management application, 2292accessible by right-clicking "My Computer" or "Computer", selecting 2293"Manage", then clicking on "Services".) 2294 2295** Emacs crashes when exiting the Emacs session 2296 2297This was reported to happen when some optional DLLs, such as those 2298used for displaying images or the GnuTLS library or zlib compression 2299library, which are loaded on-demand, have a runtime dependency on the 2300libgcc DLL, libgcc_s_dw2-1.dll. The reason seems to be a bug in 2301libgcc which rears its ugly head whenever the libgcc DLL is loaded 2302after Emacs has started. 2303 2304One solution for this problem is to find an alternative build of the 2305same optional library that does not depend on the libgcc DLL. 2306 2307Another possibility is to rebuild Emacs with the -shared-libgcc 2308switch, which will force Emacs to load libgcc_s_dw2-1.dll on startup, 2309ahead of any optional DLLs loaded on-demand later in the session. 2310 2311** File selection dialog opens in incorrect directories 2312 2313Invoking the file selection dialog on Windows 7 or later shows a 2314directory that is different from what was passed to 'read-file-name' 2315or 'x-file-dialog' via their arguments. 2316 2317This is due to a deliberate change in behavior of the file selection 2318dialogs introduced in Windows 7. It is explicitly described in the 2319MSDN documentation of the GetOpenFileName API used by Emacs to pop up 2320the file selection dialog. For the details, see 2321 2322 http://msdn.microsoft.com/en-us/library/windows/desktop/ms646839%28v=vs.85%29.aspx 2323 2324The dialog shows the last directory in which the user selected a file 2325in a previous invocation of the dialog with the same initial 2326directory. 2327 2328You can reset this "memory" of that directory by invoking the file 2329selection dialog with a different initial directory. 2330 2331** PATH can contain unexpanded environment variables 2332 2333Old releases of TCC (version 9) and 4NT (up to version 8) do not correctly 2334expand App Paths entries of type REG_EXPAND_SZ. When Emacs is run from TCC 2335and such an entry exists for emacs.exe, exec-path will contain the 2336unexpanded entry. This has been fixed in TCC 10. For more information, 2337see bug#2062. 2338 2339** Setting w32-pass-rwindow-to-system and w32-pass-lwindow-to-system to nil 2340does not prevent the Start menu from popping up when the left or right 2341"Windows" key is pressed. 2342 2343This was reported to happen when XKeymacs is installed. At least with 2344XKeymacs Version 3.47, deactivating XKeymacs when Emacs is active is 2345not enough to avoid its messing with the keyboard input. Exiting 2346XKeymacs completely is reported to solve the problem. 2347 2348** Pasting from Windows clipboard into Emacs doesn't work. 2349 2350This was reported to be the result of an anti-virus software blocking 2351the clipboard-related operations when a Web browser is open, for 2352security reasons. The solution is to close the Web browser while 2353working in Emacs, or to add emacs.exe to the list of applications that 2354are allowed to use the clipboard when the Web browser is open. 2355 2356** "Pinning" Emacs to the taskbar doesn't work on Windows 10 2357 2358"Doesn't work" here means that if you invoke Emacs by clicking on the 2359pinned icon, a separate button appears on the taskbar, instead of the 2360expected effect of the icon you clicked on being converted to that 2361button. 2362 2363This is due to a bug in early versions of Windows 10, reportedly fixed 2364in build 1511 of Windows 10 (a.k.a. "Windows 10 SP1"). If you cannot 2365upgrade, read the work-around described below. 2366 2367First, be sure to edit the Properties of the pinned icon to invoke 2368runemacs.exe, not emacs.exe. (The latter will cause an extra cmd 2369window to appear when you invoke Emacs from the pinned icon.) 2370 2371But the real cause of the problem is the fact that the pinned icon 2372(which is really a shortcut in a special directory) lacks a unique 2373application-defined Application User Model ID (AppUserModelID) that 2374identifies the current process to the taskbar. This identifier allows 2375an application to group its associated processes and windows under a 2376single taskbar button. Emacs on Windows specifies a unique 2377AppUserModelID when it starts, but Windows 10, unlike previous 2378versions of MS-Windows, does not propagate that ID to the pinned icon. 2379 2380To work around this, use some utility, such as 'win7appid', to set the 2381AppUserModelID of the pinned icon to the string "Gnu.Emacs". The 2382shortcut files corresponding to icons you pinned are stored by Windows 2383in the following subdirectory of your user's directory (by default 2384C:\Users\<UserName>\): 2385 2386 AppData\Roaming\Microsoft\Internet Explorer\Quick Launch\User Pinned\TaskBar 2387 2388Look for the file 'emacs.lnk' there. 2389 2390** Windows 95 and networking. 2391 2392To support server sockets, Emacs loads ws2_32.dll. If this file is 2393missing, all Emacs networking features are disabled. 2394 2395Old versions of Windows 95 may not have the required DLL. To use 2396Emacs's networking features on Windows 95, you must install the 2397"Windows Socket 2" update available from MicroSoft's support Web. 2398 2399** Emacs exits with "X protocol error" when run with an X server for MS-Windows. 2400 2401A certain X server for Windows had a bug which caused this. 2402Supposedly the newer 32-bit version of this server doesn't have the 2403problem. 2404 2405** Emacs crashes when opening a file with a UNC path and rails-mode is loaded. 2406 2407Loading rails-mode seems to interfere with UNC path handling. This has been 2408reported as a bug against both Emacs and rails-mode, so look for an updated 2409rails-mode that avoids this crash, or avoid using UNC paths if using 2410rails-mode. 2411 2412** M-x term does not work on MS-Windows. 2413 2414TTY emulation on Windows is undocumented, and programs such as stty 2415which are used on POSIX platforms to control tty emulation do not 2416exist for native windows terminals. 2417 2418** Using create-fontset-from-ascii-font or the --font startup parameter 2419with a Chinese, Japanese or Korean font leads to display problems. 2420Use a Latin-only font as your default font. If you want control over 2421which font is used to display Chinese, Japanese or Korean character, 2422use create-fontset-from-fontset-spec to define a fontset. 2423 2424** Frames are not refreshed while dialogs or menus are displayed 2425 2426This means no redisplay while the File or Font dialog or a pop-up menu 2427is displayed. This also means tooltips with help text for pop-up 2428menus are not displayed at all (except in a TTY session, where the help 2429text is shown in the echo area). This is because message handling 2430under Windows is synchronous, so we cannot handle repaint (or any 2431other) messages while waiting for a system function, which popped up 2432the menu/dialog, to return the result of the dialog or pop-up menu 2433interaction. 2434 2435** Help text in tooltips does not work on old Windows versions 2436 2437Windows 95 and Windows NT up to version 4.0 do not support help text 2438for menus. Help text is only available in later versions of Windows. 2439 2440** Display problems with ClearType method of smoothing 2441 2442When "ClearType" method is selected as the "method to smooth edges of 2443screen fonts" (in Display Properties, Appearance tab, under 2444"Effects"), there are various problems related to display of 2445characters: Bold fonts can be hard to read, small portions of some 2446characters could appear chopped, etc. This happens because, under 2447ClearType, characters are drawn outside their advertised bounding box. 2448Emacs 21 disabled the use of ClearType, whereas Emacs 22 allows it and 2449has some code to enlarge the width of the bounding box. Apparently, 2450this display feature needs more changes to get it 100% right. A 2451workaround is to disable ClearType. 2452 2453** Cursor is displayed as a thin vertical bar and cannot be changed 2454 2455This is known to happen if the Windows Magnifier is turned on before 2456the Emacs session starts. The Magnifier affects the cursor shape and 2457prevents any changes to it by setting the 'cursor-type' variable or 2458frame parameter. 2459 2460The solution is to log off and on again, and then start the Emacs 2461session only after turning the Magnifier off. 2462 2463To turn the Windows Magnifier off, click "Start->All Programs", or 2464"All Apps", depending on your Windows version, then select 2465"Accessibility" and click "Magnifier". In the Magnifier Settings 2466dialog that opens, click "Exit". 2467 2468** Problems with mouse-tracking and focus management 2469 2470There are problems with display if mouse-tracking is enabled and the 2471mouse is moved off a frame, over another frame then back over the first 2472frame. A workaround is to click the left mouse button inside the frame 2473after moving back into it. 2474 2475Some minor flickering still persists during mouse-tracking, although 2476not as severely as in 21.1. 2477 2478An inactive cursor remains in an active window after the Windows 2479Manager driven switch of the focus, until a key is pressed. 2480 2481** Problems with Windows input methods 2482 2483Some of the Windows input methods cause the keyboard to send 2484characters encoded in the appropriate coding system (e.g., ISO 8859-1 2485for Latin-1 characters, ISO 8859-8 for Hebrew characters, etc.). To 2486make these input methods work with Emacs on Windows 9X, you might need 2487to set the keyboard coding system to the appropriate value after you 2488activate the Windows input method. For example, if you activate the 2489Hebrew input method, type this: 2490 2491 C-x RET k hebrew-iso-8bit RET 2492 2493In addition, to use these Windows input methods, you might need to set 2494your "Language for non-Unicode programs" (on Windows XP, this is on 2495the Advanced tab of Regional Settings) to the language of the input 2496method. 2497 2498To bind keys that produce non-ASCII characters with modifiers, you 2499must specify raw byte codes. For instance, if you want to bind 2500META-a-grave to a command, you need to specify this in your '~/.emacs': 2501 2502 (global-set-key [?\M-\340] ...) 2503 2504The above example is for the Latin-1 environment where the byte code 2505of the encoded a-grave is 340 octal. For other environments, use the 2506encoding appropriate to that environment. 2507 2508** Problems with the %b format specifier for format-time-string 2509 2510The %b specifier for format-time-string does not produce abbreviated 2511month names with consistent widths for some locales on some versions 2512of Windows. This is caused by a deficiency in the underlying system 2513library function. 2514 2515** Non-US time zones. 2516 2517Many non-US time zones are implemented incorrectly. This is due to 2518over-simplistic handling of daylight savings switchovers by the 2519Windows libraries. 2520 2521** Files larger than 4GB report wrong size in a 32-bit Windows build 2522 2523Files larger than 4GB cause overflow in the size (represented as a 252432-bit integer) reported by 'file-attributes'. This affects Dired as 2525well, since the Windows port uses a Lisp emulation of 'ls', which relies 2526on 'file-attributes'. 2527 2528** Playing sound doesn't support the :data method 2529 2530Sound playing is not supported with the ':data DATA' key-value pair. 2531You _must_ use the ':file FILE' method. 2532 2533** Typing Alt-Shift has strange effects on MS-Windows. 2534 2535This combination of keys is a command to change keyboard layout. If 2536you proceed to type another non-modifier key before you let go of Alt 2537and Shift, the Alt and Shift act as modifiers in the usual way. A 2538more permanent work around is to change it to another key combination, 2539or disable it in the "Regional and Language Options" applet of the 2540Control Panel. (The exact sequence of mouse clicks in the "Regional 2541and Language Options" applet needed to find the key combination that 2542changes the keyboard layout depends on your Windows version; for XP, 2543in the Languages tab, click "Details" and then "Key Settings".) 2544 2545** Interrupting Cygwin port of Bash from Emacs doesn't work. 2546 2547Cygwin 1.x builds of the ported Bash cannot be interrupted from the 2548MS-Windows version of Emacs. This is due to some change in the Bash 2549port or in the Cygwin library which apparently make Bash ignore the 2550keyboard interrupt event sent by Emacs to Bash. (Older Cygwin ports 2551of Bash, up to b20.1, did receive SIGINT from Emacs.) 2552 2553** Accessing remote files with ange-ftp hangs the MS-Windows version of Emacs. 2554 2555If the FTP client is the Cygwin port of GNU 'ftp', this appears to be 2556due to some bug in the Cygwin DLL or some incompatibility between it 2557and the implementation of asynchronous subprocesses in the Windows 2558port of Emacs. Specifically, some parts of the FTP server responses 2559are not flushed out, apparently due to buffering issues, which 2560confuses ange-ftp. 2561 2562The solution is to downgrade to an older version of the Cygwin DLL 2563(version 1.3.2 was reported to solve the problem), or use the stock 2564Windows FTP client, usually found in the 'C:\WINDOWS' or 'C:\WINNT' 2565directory. To force ange-ftp use the stock Windows client, set the 2566variable 'ange-ftp-ftp-program-name' to the absolute file name of the 2567client's executable. For example: 2568 2569 (setq ange-ftp-ftp-program-name "c:/windows/ftp.exe") 2570 2571If you want to stick with the Cygwin FTP client, you can work around 2572this problem by putting this in your '.emacs' file: 2573 2574 (setq ange-ftp-ftp-program-args '("-i" "-n" "-g" "-v" "--prompt" "") 2575 2576** lpr commands don't work on MS-Windows with some cheap printers. 2577 2578This problem may also strike other platforms, but the solution is 2579likely to be a global one, and not Emacs specific. 2580 2581Many cheap inkjet, and even some cheap laser printers, do not 2582print plain text anymore, they will only print through graphical 2583printer drivers. A workaround on MS-Windows is to use Windows's basic 2584built in editor to print (this is possibly the only useful purpose it 2585has): 2586 2587(setq printer-name "") ; notepad takes the default 2588(setq lpr-command "notepad") ; notepad 2589(setq lpr-switches nil) ; not needed 2590(setq lpr-printer-switch "/P") ; run notepad as batch printer 2591 2592** Antivirus software interacts badly with the MS-Windows version of Emacs. 2593 2594The usual manifestation of these problems is that subprocesses don't 2595work or even wedge the entire system. In particular, "M-x shell RET" 2596was reported to fail to work. But other commands also sometimes don't 2597work when an antivirus package is installed. 2598 2599The solution is to switch the antivirus software to a less aggressive 2600mode (e.g., disable the "auto-protect" feature), or even uninstall 2601or disable it entirely. 2602 2603** Pressing the mouse button on MS-Windows does not give a mouse-2 event. 2604 2605This is usually a problem with the mouse driver. Because most Windows 2606programs do not do anything useful with the middle mouse button, many 2607mouse drivers allow you to define the wheel press to do something 2608different. Some drivers do not even have the option to generate a 2609middle button press. In such cases, setting the wheel press to 2610"scroll" sometimes works if you press the button twice. Trying a 2611generic mouse driver might help. 2612 2613One particular situation where this happens is when you have 2614"Microsoft Intellipoint" installed, which runs the program 2615ipoint.exe. The fix is reportedly to uninstall this software. 2616 2617** Scrolling the mouse wheel on MS-Windows always scrolls the top window. 2618 2619This is another common problem with mouse drivers. Instead of 2620generating scroll events, some mouse drivers try to fake scroll bar 2621movement. But they are not intelligent enough to handle multiple 2622scroll bars within a frame. Trying a generic mouse driver might help. 2623 2624** Mail sent through Microsoft Exchange in some encodings appears to be 2625mangled and is not seen correctly in Rmail or Gnus. We don't know 2626exactly what happens, but it isn't an Emacs problem in cases we've 2627seen. 2628 2629** On MS-Windows, you cannot use the right-hand ALT key and the left-hand 2630CTRL key together to type a Control-Meta character. 2631 2632This is a consequence of a misfeature beyond Emacs's control. 2633 2634Under Windows, the AltGr key on international keyboards generates key 2635events with the modifiers Right-Alt and Left-Ctrl. Since Emacs cannot 2636distinguish AltGr from an explicit Right-Alt and Left-Ctrl 2637combination, whenever it sees Right-Alt and Left-Ctrl it assumes that 2638AltGr has been pressed. The variable 'w32-recognize-altgr' can be set 2639to nil to tell Emacs that AltGr is really Ctrl and Alt. 2640 2641** Under some X-servers running on MS-Windows, Emacs's display is incorrect. 2642 2643The symptoms are that Emacs does not completely erase blank areas of the 2644screen during scrolling or some other screen operations (e.g., selective 2645display or when killing a region). M-x recenter will cause the screen 2646to be completely redisplayed and the "extra" characters will disappear. 2647 2648This is known to occur under Exceed 6, and possibly earlier versions 2649as well; it is reportedly solved in version 6.2.0.16 and later. The 2650problem lies in the X-server settings. 2651 2652There are reports that you can solve the problem with Exceed by 2653running 'Xconfig' from within NT, choosing "X selection", then 2654un-checking the boxes "auto-copy X selection" and "auto-paste to X 2655selection". 2656 2657If this does not work, please inform bug-gnu-emacs@gnu.org. Then 2658please call support for your X-server and see if you can get a fix. 2659If you do, please send it to bug-gnu-emacs@gnu.org so we can list it here. 2660 2661 2662* Runtime problems specific to macOS 2663 2664** macOS doesn't come with libxpm, so only XPM3 is supported. 2665 2666Libxpm is available for macOS as part of the XQuartz project. 2667 2668** The color list can become corrupt. 2669 2670This can be seen when Emacs is run from the command line and produces 2671output containing the text: 2672 2673 non-keyed archive cannot be decoded by NSKeyedUnarchiver 2674 2675The solution is to delete '$HOME/Library/Colors/Emacs.clr'. 2676 2677 2678* Build-time problems 2679 2680** Configuration 2681 2682*** 'configure' warns "accepted by the compiler, rejected by the preprocessor". 2683 2684This indicates a mismatch between the C compiler and preprocessor that 2685configure is using. For example, on Solaris 10 trying to use 2686CC=/opt/SUNWspro/bin/cc (the Sun Studio compiler) together with 2687CPP=/usr/ccs/lib/cpp can result in errors of this form (you may also 2688see the error '"/usr/include/sys/isa_defs.h", line 500: undefined control'). 2689 2690The solution is to tell configure to use the correct C preprocessor 2691for your C compiler (CPP="/opt/SUNWspro/bin/cc -E" in the above 2692example). 2693 2694** Compilation 2695 2696*** Building Emacs over NFS fails with "Text file busy". 2697 2698This was reported to happen when building Emacs on a GNU/Linux system 2699(Red Hat Linux 6.2) using a build directory automounted from Solaris 2700(SunOS 5.6) file server, but it might not be limited to that 2701configuration alone. Presumably, the NFS server doesn't commit the 2702files' data to disk quickly enough, and the Emacs executable file is 2703left "busy" for several seconds after Emacs has finished dumping 2704itself. This causes the subsequent commands which invoke the dumped 2705Emacs executable to fail with the above message. 2706 2707In some of these cases, a time skew between the NFS server and the 2708machine where Emacs is built is detected and reported by GNU Make 2709(it says that some of the files have modification time in the future). 2710This might be a symptom of NFS-related problems. 2711 2712If the NFS server runs on Solaris, apply the Solaris patch 105379-05 2713(Sunos 5.6: /kernel/misc/nfssrv patch). If that doesn't work, or if 2714you have a different version of the OS or the NFS server, you can 2715force the NFS server to use 1KB blocks, which was reported to fix the 2716problem albeit at a price of slowing down file I/O. You can force 1KB 2717blocks by specifying the "-o rsize=1024,wsize=1024" options to the 2718'mount' command, or by adding ",rsize=1024,wsize=1024" to the mount 2719options in the appropriate system configuration file, such as 2720'/etc/auto.home'. 2721 2722Alternatively, when Make fails due to this problem, you could wait for 2723a few seconds and then invoke Make again. In one particular case, 2724waiting for 10 or more seconds between the two Make invocations seemed 2725to work around the problem. 2726 2727Similar problems can happen if your machine NFS-mounts a directory 2728onto itself. Suppose the Emacs sources live in '/usr/local/src' and 2729you are working on the host called 'marvin'. Then an entry in the 2730'/etc/fstab' file like the following is asking for trouble: 2731 2732 marvin:/usr/local/src /usr/local/src ...options.omitted... 2733 2734The solution is to remove this line from '/etc/fstab'. 2735 2736*** Building a 32-bit executable on a 64-bit GNU/Linux architecture. 2737 2738First ensure that the necessary 32-bit system libraries and include 2739files are installed. Then use: 2740 2741 env CC="gcc -m32" ./configure --build=i386-linux-gnu --x-libraries=/usr/lib 2742 2743(using the location of the 32-bit X libraries on your system). 2744 2745*** Building on FreeBSD 11 fails at link time due to unresolved symbol 2746 2747The symbol is sendmmsg@FBSD_1.4. This is due to a faulty libgio 2748library on these systems. The solution is to reconfigure Emacs while 2749disabling all the features that require libgio: rsvg, dbus, gconf, and 2750imagemagick. 2751 2752*** Building Emacs for Cygwin can fail with GCC 3 2753 2754As of Emacs 22.1, there have been stability problems with Cygwin 2755builds of Emacs using GCC 3. Cygwin users are advised to use GCC 4. 2756 2757*** Building Emacs 23.3 and later will fail under Cygwin 1.5.19 2758 2759This is a consequence of a change to src/dired.c on 2010-07-27. The 2760issue is that Cygwin 1.5.19 did not have d_ino in 'struct dirent'. 2761See 2762 2763 https://lists.gnu.org/r/emacs-devel/2010-07/msg01266.html 2764 2765*** Building the native MS-Windows port fails due to unresolved externals 2766 2767The linker error messages look like this: 2768 2769 oo-spd/i386/ctags.o:ctags.c:(.text+0x156e): undefined reference to `_imp__re_set_syntax' 2770 collect2: ld returned 1 exit status 2771 2772This happens because GCC finds an incompatible regex.h header 2773somewhere on the include path, before the version of regex.h supplied 2774with Emacs. One such incompatible version of regex.h is part of the 2775GnuWin32 Regex package. 2776 2777The solution is to remove the incompatible regex.h from the include 2778path, when compiling Emacs. Alternatively, re-run the configure.bat 2779script with the "-isystem C:/GnuWin32/include" switch (adapt for your 2780system's place where you keep the GnuWin32 include files) -- this will 2781cause the compiler to search headers in the directories specified by 2782the Emacs Makefile _before_ it looks in the GnuWin32 include 2783directories. 2784 2785*** Building the native MS-Windows port with Cygwin GCC can fail. 2786 2787Emacs may not build using some Cygwin builds of GCC, such as Cygwin 2788version 1.1.8, using the default configure settings. It appears to be 2789necessary to specify the -mwin32 flag when compiling, and define 2790__MSVCRT__, like so: 2791 2792 configure --with-gcc --cflags -mwin32 --cflags -D__MSVCRT__ 2793 2794*** Building the MS-Windows port fails with a CreateProcess failure. 2795 2796Some versions of mingw32 make on some versions of Windows do not seem 2797to detect the shell correctly. Try "make SHELL=cmd.exe", or if that 2798fails, try running make from Cygwin bash instead. 2799 2800*** Building 'ctags' for MS-Windows with the MinGW port of GCC fails. 2801 2802This might happen due to a bug in the MinGW header assert.h, which 2803defines the 'assert' macro with a trailing semi-colon. The following 2804patch to assert.h should solve this: 2805 2806 *** include/assert.h.orig Sun Nov 7 02:41:36 1999 2807 --- include/assert.h Mon Jan 29 11:49:10 2001 2808 *************** 2809 *** 41,47 **** 2810 /* 2811 * If not debugging, assert does nothing. 2812 */ 2813 ! #define assert(x) ((void)0); 2814 2815 #else /* debugging enabled */ 2816 2817 --- 41,47 ---- 2818 /* 2819 * If not debugging, assert does nothing. 2820 */ 2821 ! #define assert(x) ((void)0) 2822 2823 #else /* debugging enabled */ 2824 2825 2826*** Building the MS-Windows port with Visual Studio 2005 fails. 2827 2828Microsoft no longer ships the single threaded version of the C library 2829with their compiler, and the multithreaded static library is missing 2830some functions that Microsoft have deemed non-threadsafe. The 2831dynamically linked C library has all the functions, but there is a 2832conflict between the versions of malloc in the DLL and in Emacs, which 2833is not resolvable due to the way Windows does dynamic linking. 2834 2835We recommend the use of the MinGW port of GCC for compiling Emacs, as 2836not only does it not suffer these problems, but it is also Free 2837software like Emacs. 2838 2839*** Building the MS-Windows port with Visual Studio fails compiling emacs.rc 2840 2841If the build fails with the following message then the problem 2842described here most likely applies: 2843 2844../nt/emacs.rc(1) : error RC2176 : old DIB in icons\emacs.ico; pass it 2845through SDKPAINT 2846 2847The Emacs icon contains a high resolution PNG icon for Vista, which is 2848not recognized by older versions of the resource compiler. There are 2849several workarounds for this problem: 2850 1. Use Free MinGW tools to compile, which do not have this problem. 2851 2. Install the latest Windows SDK. 2852 3. Replace emacs.ico with an older or edited icon. 2853 2854*** Building the MS-Windows port complains about unknown escape sequences. 2855 2856Errors and warnings can look like this: 2857 2858 w32.c:1959:27: error: \x used with no following hex digits 2859 w32.c:1959:27: warning: unknown escape sequence '\i' 2860 2861This happens when paths using backslashes are passed to the compiler or 2862linker (via -I and possibly other compiler flags); when these paths are 2863included in source code, the backslashes are interpreted as escape sequences. 2864See https://lists.gnu.org/r/emacs-devel/2010-07/msg00995.html 2865 2866The fix is to use forward slashes in all paths passed to the compiler. 2867 2868** Linking 2869 2870*** Building Emacs with a system compiler fails to link because of an 2871undefined symbol such as __eprintf which does not appear in Emacs. 2872 2873This can happen if some of the libraries linked into Emacs were built 2874with GCC, but Emacs itself is being linked with a compiler other than 2875GCC. Object files compiled with GCC might need some helper functions 2876from libgcc.a, the library which comes with GCC, but the system 2877compiler does not instruct the linker to search libgcc.a during the 2878link stage. 2879 2880A solution is to link with GCC, like this: 2881 2882 make CC=gcc 2883 2884Since the .o object files already exist, this will not recompile Emacs 2885with GCC, but just restart by trying again to link temacs. 2886 2887*** Building Emacs with -lcurses fails with undefined symbols like BC. 2888 2889The 'configure' script attempts to use several terminal libraries, 2890including tinfo, ncurses, and terminfo, and curses (in that order). 2891If it happens to choose the long-obsolete curses library, Emacs will 2892not link correctly. Emacs 28 is expected to work around this problem; 2893in the meantime you can work around it by installing tinfo, ncurses or 2894terminfo instead. 2895 2896This problem can happen on AIX 7.2 if you build with IBM's compiler XLC, 2897as AIX's ncurses library suffers from the libgcc problem mentioned above. 2898To work around this, configure and build with GCC. 2899 2900*** Sun with acc: Link failure when using acc on a Sun. 2901 2902To use acc, you need additional options just before the libraries, such as 2903 2904 /usr/lang/SC2.0.1/values-Xt.o -L/usr/lang/SC2.0.1/cg87 -L/usr/lang/SC2.0.1 2905 2906and you need to add -lansi just before -lc. 2907 2908The precise file names depend on the compiler version, so we 2909cannot easily arrange to supply them. 2910 2911*** 'tparam' reported as a multiply-defined symbol when linking with ncurses. 2912 2913This problem results from an incompatible change in ncurses, in 2914version 1.9.9e approximately. This version is unable to provide a 2915definition of tparm without also defining tparam. This is also 2916incompatible with Terminfo; as a result, the Emacs Terminfo support 2917does not work with this version of ncurses. 2918 2919The fix is to install a newer version of ncurses, such as version 4.2. 2920 2921** Bootstrapping 2922 2923Bootstrapping (compiling the .el files) is normally only necessary 2924with development builds, since the .elc files are pre-compiled in releases. 2925 2926*** "No rule to make target" with Ubuntu 8.04 make 3.81-3build1 2927 2928Compiling the lisp files fails at random places, complaining: 2929"No rule to make target '/path/to/some/lisp.elc'". 2930The causes of this problem are not understood. Using GNU make 3.81 compiled 2931from source, rather than the Ubuntu version, worked. 2932See <URL:https://debbugs.gnu.org/327>, <URL:https://debbugs.gnu.org/821>. 2933 2934** Dumping 2935 2936*** Segfault during 'make' 2937 2938If Emacs segfaults when 'make' executes one of these commands: 2939 2940 LC_ALL=C ./temacs -batch -l loadup bootstrap 2941 LC_ALL=C ./temacs -batch -l loadup dump 2942 2943the problem may be due to inadequate workarounds for address space 2944layout randomization (ASLR), an operating system feature that 2945randomizes the virtual address space of a process. ASLR is commonly 2946enabled in Linux and NetBSD kernels, and is intended to deter exploits 2947of pointer-related bugs in applications. If ASLR is enabled, the 2948command: 2949 2950 cat /proc/sys/kernel/randomize_va_space # GNU/Linux 2951 sysctl security.pax.aslr.global # NetBSD 2952 2953outputs a nonzero value. 2954 2955These segfaults should not occur on most modern systems, because the 2956Emacs build procedure uses the command 'setfattr' or 'paxctl' to mark 2957the Emacs executable as requiring non-randomized address space, and 2958Emacs uses the 'personality' system call to disable address space 2959randomization when dumping. However, older kernels may not support 2960'setfattr', 'paxctl', or 'personality', and newer Linux kernels have a 2961secure computing mode (seccomp) that can be configured to disable the 2962'personality' call. 2963 2964It may be possible to work around the 'personality' problem in a newer 2965Linux kernel by configuring seccomp to allow the 'personality' call. 2966For example, if you are building Emacs under Docker, you can run the 2967Docker container with a security profile that allows 'personality' by 2968using Docker's --security-opt option with an appropriate profile; see 2969<https://docs.docker.com/engine/security/seccomp/>. 2970 2971To work around the ASLR problem in either an older or a newer kernel, 2972you can temporarily disable the feature while building Emacs. On 2973GNU/Linux you can do so using the following command (as root). 2974 2975 echo 0 > /proc/sys/kernel/randomize_va_space 2976 2977You can re-enable the feature when you are done, by echoing the 2978original value back to the file. NetBSD uses a different command, 2979e.g., 'sysctl -w security.pax.aslr.global=0'. 2980 2981Alternatively, you can try using the 'setarch' command when building 2982temacs like this, where -R disables address space randomization: 2983 2984 setarch $(uname -m) -R make 2985 2986ASLR is not the only problem that can break Emacs dumping. Another 2987issue is that in Red Hat Linux kernels, Exec-shield is enabled by 2988default, and this creates a different memory layout. Emacs should 2989handle this at build time, but if this fails the following 2990instructions may be useful. Exec-shield is enabled on your system if 2991 2992 cat /proc/sys/kernel/exec-shield 2993 2994prints a nonzero value. You can temporarily disable it as follows: 2995 2996 echo 0 > /proc/sys/kernel/exec-shield 2997 2998As with randomize_va_space, you can re-enable Exec-shield when you are 2999done, by echoing the original value back to the file. 3000 3001*** temacs prints "Pure Lisp storage exhausted". 3002 3003This means that the Lisp code loaded from the .elc and .el files during 3004'temacs --batch --load loadup dump' took up more space than was allocated. 3005 3006This could be caused by 3007 1) adding code to the preloaded Lisp files 3008 2) adding more preloaded files in loadup.el 3009 3) having a site-init.el or site-load.el which loads files. 3010 Note that ANY site-init.el or site-load.el is nonstandard; 3011 if you have received Emacs from some other site and it contains a 3012 site-init.el or site-load.el file, consider deleting that file. 3013 4) getting the wrong .el or .elc files 3014 (not from the directory you expected). 3015 5) deleting some .elc files that are supposed to exist. 3016 This would cause the source files (.el files) to be 3017 loaded instead. They take up more room, so you lose. 3018 6) a bug in the Emacs distribution which underestimates the space required. 3019 3020If the need for more space is legitimate, change the definition 3021of PURESIZE in puresize.h. 3022 3023But in some of the cases listed above, this problem is a consequence 3024of something else that is wrong. Be sure to check and fix the real problem. 3025 3026*** OpenBSD 4.0 macppc: Segfault during dumping. 3027 3028The build aborts with signal 11 when the command './temacs --batch 3029--load loadup bootstrap' tries to load files.el. A workaround seems 3030to be to reduce the level of compiler optimization used during the 3031build (from -O2 to -O1). It is possible this is an OpenBSD 3032GCC problem specific to the macppc architecture, possibly only 3033occurring with older versions of GCC (e.g. 3.3.5). 3034 3035*** openSUSE 10.3: Segfault in bcopy during dumping. 3036 3037This is due to a bug in the bcopy implementation in openSUSE 10.3. 3038It is/will be fixed in an openSUSE update. 3039 3040** First execution 3041 3042*** Emacs binary is not in executable format, and cannot be run. 3043 3044This was reported to happen when Emacs is built in a directory mounted 3045via NFS, for some combinations of NFS client and NFS server. 3046Usually, the file 'emacs' produced in these cases is full of 3047binary null characters, and the 'file' utility says: 3048 3049 emacs: ASCII text, with no line terminators 3050 3051We don't know what exactly causes this failure. A work-around is to 3052build Emacs in a directory on a local disk. 3053 3054*** The dumped Emacs crashes when run, trying to write pure data. 3055 3056On a system where getpagesize is not a system call, it is defined 3057as a macro. If the definition (in both unex*.c and malloc.c) is wrong, 3058it can cause problems like this. You might be able to find the correct 3059value in the man page for a.out(5). 3060 3061* 'make check' failures 3062 3063** emacs-module-tests fail on Ubuntu 16.04 3064 3065This is due to a bug in GCC that was fixed in 2015; see 3066<https://lists.gnu.org/r/emacs-devel/2018-09/msg00548.html>. 3067You can work around the problem by using a later version of GCC or of 3068Ubuntu, or by configuring without modules. 3069 3070* Problems on legacy systems 3071 3072This section covers bugs reported on very old hardware or software. 3073If you are using hardware and an operating system shipped after 2000, 3074it is unlikely you will see any of these. 3075 3076*** Solaris 2.x 3077 3078**** Strange results from format %d in a few cases, on a Sun. 3079 3080Sun compiler version SC3.0 has been found to miscompile part of editfns.c. 3081The workaround is to compile with some other compiler such as GCC. 3082 3083**** On Solaris, Emacs dumps core if lisp-complete-symbol is called. 3084 3085If you compile Emacs with the -fast or -xO4 option with version 3.0.2 3086of the Sun C compiler, Emacs dumps core when lisp-complete-symbol is 3087called. The problem does not happen if you compile with GCC. 3088 3089**** On Solaris, Emacs crashes if you use (display-time). 3090 3091This can happen if you configure Emacs without specifying the precise 3092version of Solaris that you are using. 3093 3094**** Solaris 2.x: GCC complains "64 bit integer types not supported". 3095 3096This suggests that GCC is not installed correctly. Most likely you 3097are using GCC 2.7.2.3 (or earlier) on Solaris 2.6 (or later); this 3098does not work without patching. To run GCC 2.7.2.3 on Solaris 2.6 or 3099later, you must patch fixinc.svr4 and reinstall GCC from scratch as 3100described in the Solaris FAQ 3101<http://www.wins.uva.nl/pub/solaris/solaris2.html>. A better fix is 3102to upgrade to GCC 2.8.1 or later. 3103 3104**** Solaris 2.7: Building Emacs with WorkShop Compilers 5.0 98/12/15 3105C 5.0 failed, apparently with non-default CFLAGS, most probably due to 3106compiler bugs. Using Sun Solaris 2.7 Sun WorkShop 6 update 1 C 3107release was reported to work without problems. It worked OK on 3108another system with Solaris 8 using apparently the same 5.0 compiler 3109and the default CFLAGS. 3110 3111**** Solaris 2.6 and 7: the Compose key does not work. 3112 3113This is a bug in Motif in Solaris. Supposedly it has been fixed for 3114the next major release of Solaris. However, if someone with Sun 3115support complains to Sun about the bug, they may release a patch. 3116If you do this, mention Sun bug #4188711. 3117 3118One workaround is to use a locale that allows non-ASCII characters. 3119For example, before invoking emacs, set the LC_ALL environment 3120variable to "en_US" (American English). The directory /usr/lib/locale 3121lists the supported locales; any locale other than "C" or "POSIX" 3122should do. 3123 3124pen@lysator.liu.se says (Feb 1998) that the Compose key does work 3125if you link with the MIT X11 libraries instead of the Solaris X11 libraries. 3126 3127** MS-Windows 95, 98, ME, and NT 3128 3129*** MS-Windows NT/95: Problems running Perl under Emacs 3130 3131'perl -de 0' just hangs when executed in an Emacs subshell. 3132The fault lies with Perl (indirectly with Windows NT/95). 3133 3134The problem is that the Perl debugger explicitly opens a connection to 3135"CON", which is the DOS/NT equivalent of "/dev/tty", for interacting 3136with the user. 3137 3138On Unix, this is okay, because Emacs (or the shell?) creates a 3139pseudo-tty so that /dev/tty is really the pipe Emacs is using to 3140communicate with the subprocess. 3141 3142On NT, this fails because CON always refers to the handle for the 3143relevant console (approximately equivalent to a tty), and cannot be 3144redirected to refer to the pipe Emacs assigned to the subprocess as 3145stdin. 3146 3147A workaround is to modify perldb.pl to use STDIN/STDOUT instead of CON. 3148 3149For Perl 4: 3150 3151 *** PERL/LIB/PERLDB.PL.orig Wed May 26 08:24:18 1993 3152 --- PERL/LIB/PERLDB.PL Mon Jul 01 15:28:16 1996 3153 *************** 3154 *** 68,74 **** 3155 $rcfile=".perldb"; 3156 } 3157 else { 3158 ! $console = "con"; 3159 $rcfile="perldb.ini"; 3160 } 3161 3162 --- 68,74 ---- 3163 $rcfile=".perldb"; 3164 } 3165 else { 3166 ! $console = ""; 3167 $rcfile="perldb.ini"; 3168 } 3169 3170 3171 For Perl 5: 3172 *** perl/5.001/lib/perl5db.pl.orig Sun Jun 04 21:13:40 1995 3173 --- perl/5.001/lib/perl5db.pl Mon Jul 01 17:00:08 1996 3174 *************** 3175 *** 22,28 **** 3176 $rcfile=".perldb"; 3177 } 3178 elsif (-e "con") { 3179 ! $console = "con"; 3180 $rcfile="perldb.ini"; 3181 } 3182 else { 3183 --- 22,28 ---- 3184 $rcfile=".perldb"; 3185 } 3186 elsif (-e "con") { 3187 ! $console = ""; 3188 $rcfile="perldb.ini"; 3189 } 3190 else { 3191 3192*** MS-Windows 95: Alt-f6 does not get through to Emacs. 3193 3194This character seems to be trapped by the kernel in Windows 95. 3195You can enter M-f6 by typing ESC f6. 3196 3197*** MS-Windows 95/98/ME: subprocesses do not terminate properly. 3198 3199This is a limitation of the Operating System, and can cause problems 3200when shutting down Windows. Ensure that all subprocesses are exited 3201cleanly before exiting Emacs. For more details, see the Emacs on MS 3202Windows FAQ (info manual "efaq-w32"). 3203 3204*** MS-Windows 95/98/ME: crashes when Emacs invokes non-existent programs. 3205 3206When a program you are trying to run is not found on the PATH, 3207Windows might respond by crashing or locking up your system. In 3208particular, this has been reported when trying to compile a Java 3209program in JDEE when javac.exe is installed, but not on the system PATH. 3210 3211** MS-DOS 3212 3213*** When compiling with DJGPP on MS-Windows NT or later, "config msdos" fails. 3214 3215If the error message is "VDM has been already loaded", this is because 3216Windows has a program called 'redir.exe' that is incompatible with a 3217program by the same name supplied with DJGPP, which is used by 3218config.bat. To resolve this, move the DJGPP's 'bin' subdirectory to 3219the front of your PATH environment variable. 3220 3221*** When Emacs compiled with DJGPP runs on Windows 2000 and later, it cannot 3222find your HOME directory. 3223 3224This was reported to happen when you click on "Save for future 3225sessions" button in a Customize buffer. You might see an error 3226message like this one: 3227 3228 basic-save-buffer-2: c:/FOO/BAR/~dosuser/: no such directory 3229 3230(The telltale sign is the "~USER" part at the end of the directory 3231Emacs complains about, where USER is your username or the literal 3232string "dosuser", which is the default username set up by the DJGPP 3233startup file DJGPP.ENV.) 3234 3235This happens when the functions 'user-login-name' and 3236'user-real-login-name' return different strings for your username as 3237Emacs sees it. To correct this, make sure both USER and USERNAME 3238environment variables are set to the same value. Windows 2000 and 3239later sets USERNAME, so if you want to keep that, make sure USER is 3240set to the same value. If you don't want to set USER globally, you 3241can do it in the [emacs] section of your DJGPP.ENV file. 3242 3243*** When Emacs compiled with DJGPP runs on Vista, it runs out of memory. 3244 3245If Emacs running on Vista displays "!MEM FULL!" in the mode line, you 3246are hitting the memory allocation bugs in the Vista DPMI server. See 3247msdos/INSTALL for how to work around these bugs (search for "Vista"). 3248 3249*** When compiling with DJGPP on MS-Windows 95, Make fails for some targets 3250like make-docfile. 3251 3252This can happen if long file name support (the setting of environment 3253variable LFN) when Emacs distribution was unpacked and during 3254compilation are not the same. See msdos/INSTALL for the explanation 3255of how to avoid this problem. 3256 3257*** Emacs compiled with DJGPP complains at startup: 3258 3259 "Wrong type of argument: internal-facep, msdos-menu-active-face" 3260 3261This can happen if you define an environment variable 'TERM'. Emacs 3262on MSDOS uses an internal terminal emulator which is disabled if the 3263value of 'TERM' is anything but the string "internal". Emacs then 3264works as if its terminal were a dumb glass teletype that doesn't 3265support faces. To work around this, arrange for 'TERM' to be 3266undefined when Emacs runs. The best way to do that is to add an 3267[emacs] section to the DJGPP.ENV file which defines an empty value for 3268'TERM'; this way, only Emacs gets the empty value, while the rest of 3269your system works as before. 3270 3271*** MS-DOS: Emacs crashes at startup. 3272 3273Some users report that Emacs 19.29 requires dpmi memory management, 3274and crashes on startup if the system does not have it. We don't 3275know why this happens--perhaps these machines don't have enough real 3276memory, or perhaps something is wrong in Emacs or the compiler. 3277However, arranging to use dpmi support is a workaround. 3278 3279You can find out if you have a dpmi host by running go32 without 3280arguments; it will tell you if it uses dpmi memory. For more 3281information about dpmi memory, consult the djgpp FAQ. (djgpp 3282is the GNU C compiler as packaged for MSDOS.) 3283 3284Compiling Emacs under MSDOS is extremely sensitive for proper memory 3285configuration. If you experience problems during compilation, consider 3286removing some or all memory resident programs (notably disk caches) 3287and make sure that your memory managers are properly configured. See 3288the djgpp faq for configuration hints. 3289 3290*** Emacs compiled with DJGPP for MS-DOS/MS-Windows cannot access files 3291in the directory with the special name 'dev' under the root of any 3292drive, e.g. 'c:/dev'. 3293 3294This is an unfortunate side-effect of the support for Unix-style 3295device names such as /dev/null in the DJGPP runtime library. A 3296work-around is to rename the problem directory to another name. 3297 3298*** MS-DOS: Emacs compiled for MSDOS cannot find some Lisp files, or other 3299run-time support files, when long filename support is enabled. 3300 3301Usually, this problem will manifest itself when Emacs exits 3302immediately after flashing the startup screen, because it cannot find 3303the Lisp files it needs to load at startup. Redirect Emacs stdout 3304and stderr to a file to see the error message printed by Emacs. 3305 3306Another manifestation of this problem is that Emacs is unable to load 3307the support for editing program sources in languages such as C and Lisp. 3308 3309This can happen if the Emacs distribution was unzipped without LFN 3310support, thus causing long filenames to be truncated to the first 6 3311characters and a numeric tail that Windows 95 normally attaches to it. 3312You should unzip the files again with a utility that supports long 3313filenames (such as djtar from DJGPP or InfoZip's UnZip program 3314compiled with DJGPP v2). The file msdos/INSTALL explains this issue 3315in more detail. 3316 3317Another possible reason for such failures is that Emacs compiled for 3318MSDOS is used on Windows NT, where long file names are not supported 3319by this version of Emacs, but the distribution was unpacked by an 3320unzip program that preserved the long file names instead of truncating 3321them to DOS 8+3 limits. To be useful on NT, the MSDOS port of Emacs 3322must be unzipped by a DOS utility, so that long file names are 3323properly truncated. 3324 3325** Apple Macintosh operating systems 3326 3327*** OS X 10.9 and earlier: symlinks autocomplete as directories 3328 3329Autocompleting the name of a symbolic link incorrectly appends "/". 3330Building and running Emacs on OS X 10.10 (or later) fixes the problem. 3331Older operating systems are no longer supported by Apple. 3332https://bugs.gnu.org/31305 3333 3334** Archaic window managers and toolkits 3335 3336*** Open Look: Under Open Look, the Emacs window disappears when you type M-q. 3337 3338Some versions of the Open Look window manager interpret M-q as a quit 3339command for whatever window you are typing at. If you want to use 3340Emacs with that window manager, you should try to configure the window 3341manager to use some other command. You can disable the 3342shortcut keys entirely by adding this line to ~/.OWdefaults: 3343 3344 OpenWindows.WindowMenuAccelerators: False 3345 3346*** twm: A position you specified in .Xdefaults is ignored, using twm. 3347 3348twm normally ignores "program-specified" positions. 3349You can tell it to obey them with this command in your '.twmrc' file: 3350 3351 UsePPosition "on" #allow clients to request a position 3352 3353** Bugs related to old DEC hardware 3354 3355*** The Compose key on a DEC keyboard does not work as Meta key. 3356 3357This shell command should fix it: 3358 3359 xmodmap -e 'keycode 0xb1 = Meta_L' 3360 3361*** Keyboard input gets confused after a beep when using a DECserver 3362as a concentrator. 3363 3364This problem seems to be a matter of configuring the DECserver to use 33657 bit characters rather than 8 bit characters. 3366 3367This file is part of GNU Emacs. 3368 3369GNU Emacs is free software: you can redistribute it and/or modify 3370it under the terms of the GNU General Public License as published by 3371the Free Software Foundation, either version 3 of the License, or 3372(at your option) any later version. 3373 3374GNU Emacs is distributed in the hope that it will be useful, 3375but WITHOUT ANY WARRANTY; without even the implied warranty of 3376MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 3377GNU General Public License for more details. 3378 3379You should have received a copy of the GNU General Public License 3380along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>. 3381 3382 3383Local variables: 3384mode: outline 3385paragraph-separate: "[ ]*$" 3386end: 3387