XEmacs FAQ
**********

This is the guide to the XEmacs Frequently Asked Questions list---a compendium of questions and answers pertaining to one of the finest programs ever written.  XEmacs is much more than just a Text Editor.

This FAQ is freely redistributable.  This FAQ is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

If you have a Web browser, the official hypertext version is at http://www.xemacs.org/FAQ/xemacs-faq.html

1 Introduction, Policy, Credits
*******************************

Learning XEmacs is a lifelong activity.  Even people who have used Emacs for years keep discovering new features.  Therefore this document cannot be complete.  Instead it is aimed at the person who is either considering XEmacs for their own use, or has just obtained it and is wondering what to do next.  It is also useful as a reference to available resources.

The previous maintainer of the FAQ was Anthony Rossini, who started it, after getting tired of hearing JWZ complain about repeatedly having to answer questions.  Ben Wing then took over and did a massive update reorganizing the whole thing.  At this point Anthony took back over, but then had to give it up again. Some of the other contributors to this FAQ are listed later in this document.

The previous version was converted to hypertext format, and edited by Steven L. Baur.  It was converted back to texinfo by Hrvoje Niksic.  The FAQ was then maintained by Andreas Kaempf, who passed it on to ChristianNybø, and then to Sandra Wambold.

The current version of the FAQ has been heavily redone by Ben Wing.

If you notice any errors or items which should be added or amended to this FAQ please send email to xemacs-beta@xemacs.org. Include XEmacs FAQ on the Subject: line.

1.0: What is XEmacs?
====================

Q1.0.1: What is XEmacs?
-----------------------

XEmacs is a powerful, highly customizable open source text editor and application development system, with full GUI support.  It is protected under the GNU Public License and related to other versions of Emacs, in particular GNU Emacs.  Its emphasis is on modern graphical user interface support and an open software development model, similar to Linux.  XEmacs has an active development community numbering in the hundreds (and thousands of active beta testers on top of this), and runs on all versions of MS Windows, on Mac OS X, on Linux, and on nearly every other version of Unix in existence. Support for XEmacs has been supplied by Sun Microsystems, University of Illinois, Lucid, ETL/Electrotechnical Laboratory, Amdahl Corporation, BeOpen, and others, as well as the unpaid time of a great number of individual developers.

Q1.0.2: What is the current version of XEmacs?
----------------------------------------------

XEmacs versions 21.4.* are releases made from the current stable sources.  XEmacs versions 21.5.* (which will be released as 22.0) are releases made from the development sources.  Check at http://www.xemacs.org for the current minor version.  XEmacs versions 21.1.* were the previous stable releases, now retired.

XEmacs 20.4, released in February 1998, was the last release of v20.

XEmacs 19.16, released in November, 1997. was the last release of v19, and was also the last version without international language support.

Q1.0.3: How do you pronounce XEmacs?
------------------------------------

The most common pronounciation is Eks eemax.

Q1.0.4: What does XEmacs look like?
-----------------------------------

Screen snapshots are available at http://www.xemacs.org/About/Screenshots/index.html as part of the XEmacs website.

Q1.0.5: Who wrote XEmacs?
-------------------------

XEmacs is the result of the time and effort of many people, and the active developers have changed over time.  There are two major components of the XEmacs effort -- writing the code itself and providing all the support work (testing the code, releasing beta and final versions, handling patches, reading bug reports, maintaining the web site, managing the mailing lists, etc. etc.).  Neither component would work without the other.

CODING
------

The primary code contributor over the years has been Ben Wing (active since late 1992).  Between 1991 and 1995, large amounts of coding was contributed by Jamie Zawinski and Chuck Thompson.  Many other people have authored major subsystems or otherwise contributed large amounts of code, including Andy Piper, Hrvoje Niksic, Jerry James, Jonathan Harris, Kyle Jones, Martin Buchholz, Michael Sperber, Olivier Galibert, Richard Mlynarik, Stig, William Perry and plenty of others.

Primary XEmacs-specific subsystems and their authors:

Objects

       - Conversion from 26-bit to 28-bit pointers and integers, lrecords, lcrecords: Richard Mlynarik, 1994

       - Conversion to 32-bit pointers and 31-bit integers: Kyle Jones, Martin Buchholz

       - Portable dumper, object descriptions: Olivier Galibert

       - KKCC (new garbage collector), ephemerons, weak boxes: Michael Sperber and students

       - Random object work (object equal and hash methods, weak lists, lcrecord lists, bit vectors, dynarr, blocktype, opaque, string resizing): Ben Wing

       - Profiling: Ben Wing

       - Some byte-compilation and hash-table improvements: Martin Buchholz

       - Bignum: Jerry James

Internationalization/Mule

       - mostly Ben Wing; many ideas for future work, Stephen Turnbull

I/O

       - Basic event/event-stream implementation: Jamie Zawinski

       - Most event work since 1994: Ben Wing

       - Asynchronous stuff (async timeouts, signals, quit-checking): Ben Wing

       - Process method abstraction, Windows process work: Kirill Katsnelson

       - Misc-user events, async timeouts, most quit-checking and signal code, most other work since 1994: Ben Wing

       - Lstreams: Ben Wing

Display

       - Redisplay mechanism: implementation, Chuck Thompson; additional work, lots of people

       - Glyphs: mostly Ben Wing

       - Specifiers: Ben Wing

       - Extents: initial implementation, someone at Lucid; rewrite, 1994, Ben Wing

       - Widgets: Andy Piper

       - JPEG/PNG/TIFF image converters: Ben Wing, William Perry, Jareth Hein, others (see comment in glyphs-eimage.c)

       - Menus: Jamie Zawinski, someone at Lucid (Lucid menus)

       - Scrollbars: Chuck Thompson, ??? (Lucid scrollbar)

       - Multi-device/device-independence work (console/device/etc methods): Ben Wing, prototype by chuck thompson

       - Faces: first implementation, Jamie Zawinski; second, chuck; third, Ben Wing

       - Fonts/colors: first implementation, Jamie Zawinski; further work, Ben Wing

       - Toolbars: implementation, chuck, much interface work, Ben Wing

       - Gutters, tabs: andy piper

Device subsystems

       - X Windows: Jamie Zawinksi, Ben Wing, others

       - GTK: William Perry, Malcolm Purvis

       - MS Windows: initial implementation, Jonathan Harris; some more work, Andy Piper, Ben Wing

       - TTY: Chuck Thompson, Ben Wing

       - Cygwin: Andy Piper

Misc

       - Configure: initial porting from fsf, Chuck Thompson; conversion to autoconf 2, much rewriting, Martin Buchholz

       - Most initialization-related code: Ben Wing

       - Internals manual, much of Lisp manual: Ben Wing

       - FSF synching: initial sync with FSF 19, Richard Mlynarik, further work, Ben Wing

SUPPORT
-------

Currently, support duties are handled by many different people.

Release managers have been

  - Stephen Turnbull (April 2001 - January 2003, March 2004 - present, 21.2.47 - 21.4.12, 21.5.2 - 21.5.7, 21.5.17 - present)

  - Vin Shelton (Mar 1997 - Jan 2001, May 2003 - present, 19.16, 21.1.3 - 21.1.14, 21.4.13 - present)

  - Steve Youngs (July 2002 - September 2003, 21.5.8 - 21.5.16)

  - Martin Buchholz (December 1998, November 1999 - May 2001, 21.2.7 - 21.2.8, 21.2.21 - 21.2.46, 21.5.0 - 21.5.1)

  - Steve Baur (early 1997 - December 1998, February 1999 - November 1999, 19.15 - 21.2.5, 21.2.9 - 21.2.20)

  - Andy Piper (December 1998, 21.2.6)

  - Chuck Thompson (June 1994 - September 1996, 19.11 - 19.14)

  - Jamie Zawinski (April 1991 - June 1994, 19.0 - 19.10)

The recent overlapping dates are intentional, since two or three trees are maintained simultaneously at any point.

Other major support work:

  - Adrian Aichner wrote and maintains the web site.

  - Stephen Turnbull has produced many of the beta and semi-stable releases and has attempted to be the "face" of XEmacs on the newsgroups and mailing lists.

  - Steve Youngs currently produces the beta releases (???).

  - Steve Youngs, Ville Skytta, and now Norbert Koch have taken turns maintaining the packages.

  - Vin Shelton maintains the stable releases.

  - Testing - #### Norbert, Adrian, ???

Portraits and email of some of the major developers:

  * Andy Piper

  * Ben Wing

  * Chuck Thompson

  * Hrvoje Niksic

  * Jamie Zawinski

  * Martin Buchholz

  * Richard Mlynarik

  * Stephen Turnbull

  * Steve Baur

Many other people have contributed to XEmacs; this is partially enumerated in the About XEmacs option in the Help menu.

Q1.0.6: Who wrote the FAQ?
--------------------------

The current version of this FAQ was created by Ben Wing.

Previous contributors to the FAQ include

  * SL Baur

  * Hrvoje Niksic

  * Curtis.N.Bingham

  * Georges Brun-Cottan

  * Richard Caley

  * Richard Cognot

  * Mark Daku

  * William G. Dubuque

  * Eric Eide

  * Alain Fauconnet

  * Chris Flatters

  * Evelyn Ginsparg

  * Marty Hall

  * Darrell Kindred

  * David Moore

  * Arup Mukherjee

  * Juergen Nickelsen

  * Kevin R. Powell

  * Justin Sheehy

  * Stig

  * Aki Vehtari

1.1: Getting XEmacs
===================

Q1.1.1: Where can I find XEmacs?
--------------------------------

To download XEmacs, visit the XEmacs WWW page at http://www.xemacs.org/Download/.  The most up-to-date list of distribution sites can always be found there.  Try to pick a site that is networkologically close to you.  If you know of other mirrors of the XEmacs archives, please send e-mail to mailto:webmaster@xemacs.org and we will list them here as well.

The canonical distribution point is ftp.xemacs.org, available either through HTTP (http://ftp.xemacs.org/) or anonymous FTP (ftp://ftp.xemacs.org/pub/xemacs/).

Q1.1.2: Are binaries available?
-------------------------------

MS Windows binaries are available at http://www.xemacs.org/Download/win32/ for the native versions of 21.4 and 21.1.  Cygwin binaries are now available as part of the standard Cygwin installation process.  XEmacs also comes pre-built as part of many Linux distributions, such as Red Hat and SuSE.

Otherwise, you will need to build XEmacs yourself or get your system administrator to do it.  Generally, this is not a difficult process under Unix and Mac OS X, as XEmacs has been tested under all of the common Unix versions and under Mac OS X and comes with an extensive configure script that is able to automatically detect most aspects of the configuration of your particular system.

Q1.1.3: How do I get the bleeding-edge sources?
-----------------------------------------------

If you are interested in developing XEmacs, or getting the absolutely most recent, up-to-the-moment, bleeding-edge source code, you can directly access the master CVS source tree (read-only, of course, until you ask for and are granted permission to directly modify portions of the source tree) at cvs.xemacs.org.  Directions on how to access the source tree are located at http://www.xemacs.org/Develop/cvsaccess.html.

Nightly CVS snapshots are available at http://www.dk.xemacs.org/Download/CVS-snapshots/.

Q1.1.4: Where can I obtain a printed copy of the XEmacs User's Manual?
----------------------------------------------------------------------

Pre-printed manuals are not available.  If you are familiar with TeX, you can generate your own manual from the XEmacs sources.

HTML and Postscript versions of XEmacs manuals are available from the XEmacs web site at http://www.xemacs.org/Documentation/index.html.

1.2: Versions for Different Operating Systems
=============================================

Q1.2.1: Do I need X11 to run XEmacs?
------------------------------------

No.  The name XEmacs is unfortunate in the sense that it is not an X Window System-only version of Emacs.  XEmacs has full color support on a color-capable character terminal.

Q1.2.2: What versions of Unix does XEmacs run on?
-------------------------------------------------

XEmacs is regularly tested on Linux, Solaris, SunOS, HP/UX, FreeBSD, OpenBSD, BSD/OS aka BSDI, Tru64 aka DEC/OSF, SCO5, and probably others.  It should work on all versions of Unix created in the last 10 years or so, perhaps with a bit of work on more obscure platforms to correct bit-rot.  It uses a sophisticated configuration system to auto-detect zillions of features that are implemented differently in different versions of Unix, so it will probably work on your vendor's version, possibly with a bit of tweaking, even if we've never heard of it.

For problems with particular machines and versions of Unix, see the PROBLEMS file.

Much effort has gone into making XEmacs work on as many different machines, configurations, and compilers as possible.

Much effort has gone into making XEmacs 64-bit clean.

Much effort has gone into removing system-specific code, and replacing such code with autodetection at configure time.

The XEmacs core should build "out of the box" on most Unix-like systems.

XEmacs 21.2 was tested and make check succeeded on these Unix configurations as of 2001-02-10:

     alphaev56-dec-osf4.0e (both Compaq C and gcc)
     i386-unknown-freebsd4.2
     i386-unknown-netbsdelf1.5
     i586-sco-sysv5uw7.0.1 (both SCO's cc and gcc)
     i686-pc-linux-gnu
     hppa2.0-hp-hpux10.20 (both HP's ANSI cc and gcc)
     mips-sgi-irix6.5 (both MIPSpro cc and gcc)
     rs6000-ibm-aix4.3.0.0 (both IBM's xlc and gcc)
     sparc-sun-solaris2.6 (both Sun's Forte C and gcc)
     sparc-sun-solaris2.7 (both Sun's Forte C and gcc)
     sparc-sun-sunos4.1.4 (gcc)

Some systems have a dual mode 32-bit/64-bit compiler.  On most of these, XEmacs requires the --pdump (in XEmacs 21.5, --enable-pdump) configure option to build correctly with the 64-bit version of the compiler.

     mips-sgi-irix6.5, CC="gcc -mabi=64"
     mips-sgi-irix6.5, CC="cc -64"
     rs6000-ibm-aix4.3.0.0, CC="cc -q64"

On most of these systems, XEmacs also builds with a C++ compiler, but not "out of the box".  This feature is only for use by the maintainers.

XEmacs 21.2 is known not to work on any machines with m680x0 processors.  Sorry, all you sun3 and Unix PC nostalgia buffs out there.

VMS has never been supported by XEmacs.  In fact, all the old VMS code inherited from Emacs has been removed.  Sorry, all you VMS fans out there.

Q1.2.3: Is there a port of XEmacs to Microsoft Windows?
-------------------------------------------------------

Yes.  Beginning with release 21.0, XEmacs has worked under MS Windows and is fully-featured and actively developed.  A group of dedicated developers actively maintains and improves the Windows-specific portions of the code.  Some of the core developers, in fact, use Windows as their only development environment, and some features, such as printing, actually work better on Windows than native Unix and Mac OS X.  The mailing list at xemacs-winnt@xemacs.org is dedicated to that effort (please use the -request address to subscribe). (Despite its name, XEmacs actually works on all versions of Windows.)

The list name is misleading, as XEmacs supports and has been compiled on Windows 95, Windows 98, Windows NT, Windows 2000, Windows ME, Windows XP, and all newer versions of Windows.  The MS Windows-specific code is based on Microsoft Win32 API, and will not work on MS Windows 3.x or on MS-DOS.

XEmacs also supports the Cygwin and MinGW development and runtime environments, where it also uses native Windows code for graphical features.  In addition, under Cygwin it is possible to compile XEmacs to use an X server (and XFree86 is available as part of the standard Cygwin installation).

Q1.2.4: Can I build XEmacs on MS Windows with X support? Do I need to?
----------------------------------------------------------------------

Yes, you can, but no you do not need to.  In fact, we recommend that you use a native-GUI version unless you have a specific need for an X version.

Q1.2.5: What are Cygwin and MinGW, and do I need them to run XEmacs?
--------------------------------------------------------------------

To answer the second part of the question: No, you, you don't need Cygwin or MinGW to build or to run XEmacs.  But if you have them and want to use them, XEmacs supports these environments.

(One important reason to support Cygwin is that it lets the MS Windows developers test out their code in a Unix environment without actually having to have a Unix machine around.  For this reason alone, Cygwin support is likely to remain supported for a long time in XEmacs.  Same goes for the X support under Cygwin, for the same reasons.  MinGW support, on the other hand, depends on volunteers to keep it up to date; but this is generally not hard.)

Cygwin is a set of tools providing Unix-like API on top of Win32. It makes it easy to port large Unix programs without significant changes to their source code.  It is a development environment as well as a runtime environment.

When built with Cygwin, XEmacs supports all display types -- TTY, X & Win32 GUI, and can be built with support for all three simultaneously. If you build with Win32 GUI support then the Cygwin version uses the majority of the Windows-specific code, which is mostly related to display.  If you want to build with X support you need X libraries (and an X server to display XEmacs on); see Q2.3.7.  TTY and Win32 GUI require no additional libraries beyond what comes standard with Cygwin.

The advantages of the Cygwin version are that it integrates well with the Cygwin environment for existing Cygwin users; uses configure so building with different features is very easy; and actively supports X & TTY.  Furthermore, the entire Cygwin environment and compiler are free, whereas Visual C++ costs money.

The disadvantage is that it requires the whole Cygwin environment, whereas the native port requires only a suitable MS Windows compiler. Also, it follows the Unix filesystem and process model very closely (some will undoubtedly view this as an advantage).

See http://www.cygwin.com/ for more information on Cygwin.

MinGW is a collection of header files and import libraries that allow one to use GCC under the Cygwin environment to compile and produce exactly the same native Win32 programs that you can using Visual C++. Programs compiled with MinGW make use of the standard Microsoft runtime library MSVCRT.DLL, present on all Windows systems, and look, feel, and act like a standard Visual-C-produced application. (The only difference is the compiler.) This means that, unlike a standardly-compiled Cygwin application, no extra runtime support (e.g. Cygwin's cygwin1.dll) is required.  This, along with the fact that GCC is free (and works in a nice Unix-y way in a nice Unix-y environment, for those die-hard Unix hackers out there), is the main advantage of MinGW.  It is also potentially faster than Cygwin because it has less overhead when calling Windows, but you lose the POSIX emulation layer, which makes Unix programs harder to port. (But this is irrelevant for XEmacs since it's already ported to Win32.)

See http://www.mingw.org/ for more information on MinGW.

Q1.2.6: What are the differences between the various MS Windows emacsen?
------------------------------------------------------------------------

XEmacs, Win-Emacs, DOS Emacs, NT Emacs, this is all very confusing. Could you briefly explain the differences between them?

Here is a recount of various Emacs versions running on MS Windows:

  * XEmacs

       - Beginning with XEmacs 19.12, XEmacs' architecture was redesigned in such a way to allow clean support of multiple window systems.  At this time the TTY support was added, making X and TTY the first two "window systems" supported by XEmacs.  The 19.12 design is the basis for the current native MS Windows code.

       - Some time during 1997, David Hobley (soon joined by Marc Paquette) imported some of the NT-specific portions of GNU Emacs, making XEmacs with X support compile under Windows NT, and creating the "X" port.

       - Several months later, Jonathan Harris sent out initial patches to use the Win32 API, thus creating the native port.  Since then, various people have contributed, including Kirill M. Katsnelson (contributed support for menubars, subprocesses and network, as well as loads of other code), Andy Piper (ported XEmacs to Cygwin environment, contributed Windows unexec, Windows-specific glyphs and toolbars code, and more), Ben Wing (loads of improvements; primary MS Windows developer since 2000), Jeff Sparkes (contributed scrollbars support) and many others.

  * NT Emacs

       - NT Emacs was an early version of GNU Emacs 19 modified to compile and run under MS Windows 95 and NT using the native Win32 API.  It was written by Geoff Voelker, and has long since been incorporated into the mainline GNU Emacs distribution.

  * Win-Emacs

       - Win-Emacs was a port of Lucid Emacs 19.6 to MS Windows using X compatibility libraries.  Win-Emacs was written by Ben Wing.  The MS Windows code never made it back to Lucid Emacs, and its creator (Pearl Software) has long since gone out of business.

  * GNU Emacs for DOS

       - GNU Emacs features support for MS-DOS and DJGPP (D.J. Delorie's DOS port of GCC).  Such an Emacs is heavily underfeatured, because it does not support long file names, lacks proper subprocesses support, and is far too big compared with typical DOS editors.

  * GNU Emacs compiled with Win32

       - Starting with GNU Emacs 19.30, it has been possible to compile GNU Emacs under MS Windows using the DJGPP compiler and X libraries.  The result is very similar to GNU Emacs compiled under MS DOS, only it works somewhat better because it runs in 32-bit mode, makes use of all the system memory, supports long file names, etc.

Q1.2.7: How does the port cope with differences in the Windows user interface?
------------------------------------------------------------------------------

The XEmacs (and Emacs in general) user interface is pretty different from what is expected of a typical MS Windows program.  How does the MS Windows port cope with it?

As a general rule, we follow native MS Windows conventions as much as possible.  21.4 is a fairly complete Windows application, supporting native printing, system file dialog boxes, tool tips, etc.  In cases where there's a clear UI conflict, we currently use normal Unix XEmacs behavior by default, but make sure the MS Windows "look and feel" (mark via shift-arrow, self-inserting deletes region, Alt selects menu items, etc.) is easily configurable (respectively: using the variable shifted-motion-keys-select-region in 21.4 and above [it's in fact the default in these versions], or the pc-select package; using the pending-del package; and setting the variable menu-accelerator-enabled to menu-force in 21.4 and above). In fact, if you use the sample init.el file as your init file, you will get all these behaviors automatically turned on.

In future versions, some of these features might be turned on by default in the MS Windows environment.

Q1.2.8: Is there a port of XEmacs to the Macintosh?
---------------------------------------------------

Yes.

XEmacs 21.5 (perhaps 21.4 also?) works on MacOS X, although it certainly will not feel very much like a Mac application as it has no Mac-specific code in it.

There is also a port of XEmacs 19.14 that works on all recent versions of MacOS, from 8.1 through MacOS X, by Pitts Jarvis (recently deceased).  It runs in an equivalent of TTY mode only (one single Macintosh window, 25 colors), but has a large number of Mac-specific additions.  It's available at http://homepage.mac.com/pjarvis/xemacs.html.

Q1.2.9: Is there a port of XEmacs to MS-DOS?
--------------------------------------------

No.  We have never supported running on MS-DOS or Windows 3.1, and in fact have long since deleted all MS-DOS-related code.  We're not particularly interested in patches for these platforms, as they would introduce huge amounts of code clutter due to the woefully underfeatured nature of these systems. (See GNU Emacs for a port to MS-DOS.)

Q1.2.10: Is there a port of XEmacs to OS/2?
-------------------------------------------

No, but Alexander Nikolaev <avn_1251@mail.ru> was at one point working on it.

Q1.2.11: Is there a port of XEmacs to NextStep?
-----------------------------------------------

Carl Edman, apparently no longer at cedman@princeton.edu, did the port of GNU Emacs to NeXTstep and expressed interest in doing the XEmacs port, but never went any farther.

Q1.2.12: Is there a port of XEmacs to VMS?
------------------------------------------

VMS has never been supported by XEmacs.  In fact, all the old VMS code inherited from GNU Emacs has been removed.  Sorry, all you VMS fans out there.

1.3: Getting Started
====================

Q1.3.1: What is an init.el or .emacs and is there a sample one?
---------------------------------------------------------------

The init.el or .emacs file is used to customize XEmacs to your tastes.  Starting in 21.4, the preferred location for the init file is ~/.xemacs/init.el; in previous versions, it was ~/.emacs.  21.4 still accepts the old location, but the first time you run it, it will ask to migrate your file to the new location. If you answer yes, the file will be moved, and a "compatibility" .emacs file will be placed in the old location so that you can still run older versions of XEmacs, and versions of GNU Emacs, which expect the old location.  The .emacs file present is just a stub that loads the real file in ~/.xemacs/init.el.

No two init files are alike, nor are they expected to be alike, but that's the point.  The XEmacs distribution contains an excellent starter example in the etc/ directory called sample.init.el (starting in 21.4) or sample.emacs in older versions.  Copy this file from there to ~/.xemacs/init.el (starting in 21.4) or ~/.emacs in older versions, where ~ means your home directory, of course.  Then edit it to suit.

You may bring the sample.init.el or sample.emacs file into an XEmacs buffer from the menubar. (The menu entry for it is always under the Help menu, but its location under that has changed in various versions.  Recently, look under the Samples submenu.)  To determine the location of the etc/ directory type the command C-h v data-directory RET.

Q1.3.2: Where do I put my init.el file?
---------------------------------------

init.el is the name of the init file starting with 21.4, and is located in the subdirectory .xemacs/ of your home directory.  In prior versions, the init file is called .emacs and is located in your home directory.

Your home directory under Windows is determined by the HOME environment variable.  If this is not set, it defaults to C:\. To set this variable, modify AUTOEXEC.BAT under Windows 95/98, or select Control Panel->System->Advanced->Environment Variables... under Windows NT/2000.

Q1.3.3: Can I use the same init.el with the other Emacs?
--------------------------------------------------------

Yes.  The sample init.el included in the XEmacs distribution will show you how to handle different versions and flavors of Emacs.

Q1.3.4: Any good XEmacs tutorials around?
-----------------------------------------

There's the XEmacs tutorial available from the Help Menu under Help->Tutorials, or by typing C-h t. To check whether it's available in a non-english language, type C-u C-h t TAB, type the first letters of your preferred language, then type RET.

Q1.3.5: May I see an example of a useful XEmacs Lisp function?
--------------------------------------------------------------

The following function does a little bit of everything useful.  It does something with the prefix argument, it examines the text around the cursor, and it's interactive so it may be bound to a key.  It inserts copies of the current word the cursor is sitting on at the cursor.  If you give it a prefix argument: C-u 3 M-x double-word then it will insert 3 copies.

     (defun double-word (count)
       "Insert a copy of the current word underneath the cursor"
       (interactive "*p")
       (let (here there string)
         (save-excursion
           (forward-word -1)
           (setq here (point))
           (forward-word 1)
           (setq there (point))
           (setq string (buffer-substring here there)))
         (while (>= count 1)
           (insert string)
           (decf count))))

The best way to see what is going on here is to let XEmacs tell you. Put the code into an XEmacs buffer, and do a C-h f with the cursor sitting just to the right of the function you want explained.  Eg.  move the cursor to the SPACE between interactive and "*p" and hit C-h f to see what the function interactive does.  Doing this will tell you that the * requires a writable buffer, and p converts the prefix argument to a number, and interactive allows you to execute the command with M-x.

Q1.3.6: And how do I bind it to a key?
--------------------------------------

To bind to a key do:

     (global-set-key "\C-cd" 'double-word)

Or interactively, M-x global-set-key and follow the prompts.

Q1.3.7: What's the difference between a macro and a function?
-------------------------------------------------------------

Quoting from the Lisp Reference (a.k.a Lispref) Manual:

Macros enable you to define new control constructs and other language features.  A macro is defined much like a function, but instead of telling how to compute a value, it tells how to compute another Lisp expression which will in turn compute the value.  We call this expression the expansion of the macro.

Macros can do this because they operate on the unevaluated expressions for the arguments, not on the argument values as functions do.  They can therefore construct an expansion containing these argument expressions or parts of them.

Do not confuse the two terms with keyboard macros, which are another matter, entirely.  A keyboard macro is a key bound to several other keys.  Refer to manual for details.

Q1.3.8: What is Custom?
-----------------------

Custom is a system for customizing XEmacs options.

You can access Advanced (Customize) from the Options menu or invoking one of customize commands by typing eg. M-x customize, M-x customize-face, M-x customize-variable or M-x customize-apropos.

There is also new browser mode for Customize. Try it out with M-x customize-browse

1.4: Getting Help
=================

Q1.4.1: Where can I get help?
-----------------------------

Probably the easiest way, if everything is installed, is to use Info, by pressing C-h i, or looking for an Info item on the Help Menu.  M-x apropos can be used to look for particular commands.

For items not found in the manual, try reading this FAQ and reading the Usenet group comp.emacs.xemacs.

If you choose to post to a newsgroup, please use comp.emacs.xemacs.  Please do not post XEmacs related questions to gnu.emacs.help.

If you cannot post or read Usenet news, there is a corresponding mailing list xemacs-news@xemacs.org which is available.  It can be subscribed to via the Mailman Web interface or by sending mail to to xemacs-news-request@xemacs.org with subscribe in the body of the message.  See also http://www.xemacs.org/Lists/#xemacs-news.  To cancel a subscription, you may use the xemacs-news-request@xemacs.org address or the Web interface.  Send a message with a subject of unsubscribe to be removed.

Q1.4.2: Which mailing lists are there?
--------------------------------------

For complete, up-to-date info on the lists and how to subscribe, see http://www.xemacs.org/Lists/.

comp.emacs.xemacs
     is a Usenet newsgroup for XEmacs users to discuss problems and issues that arise for them.  It's not generally an appropriate place to ask about apparent bugs (use xemacs-beta), or future plans (use xemacs-design).

xemacs-announce
     is a read-only, low volume list for announcements concerning the XEmacs project and new releases of the XEmacs software.

xemacs-beta
     is an open list for bug reports about beta versions of XEmacs.  This includes the bug reports themselves, by both users and developers, as well as queries, follow-ups, and discussions further determining their nature and status.  This is the primary channel for this kind of discussion; related code changes will usually not be applied until they have been discussed here.  When such discussions touch on significant changes to the code (in particular, structural changes), or on changes to API's or external functionality, they should be moved to xemacs-design.  Requests and proposals for non-bug-related changes do not belong on xemacs-beta, and should be sent to xemacs-design instead.

xemacs-beta-ja
     is an open list for bug reports and design discussion related to Mule features, including Japanese handling, in beta versions of XEmacs. Japanese is the preferred language of discussion.  For most timely presentation to reviewers, please consider sending appropriate discussion to xemacs-mule or xemacs-design in English when convenient for the participants in discussion.  When possible, bug reports not related to Mule (including Japanese) should be reported on xemacs-beta in English.

xemacs-buildreports
     is an open list for submission of build-reports on beta versions of XEmacs. For information on what the build-reports should contain, please see the `etc/BETA' file which is included in each beta distribution.

xemacs-cvs
     is a read-only list for notices and information on what has been committed to the XEmacs CVS trees, by whom, and for what.

xemacs-design
     is an open list for discussing the design of XEmacs.  This includes discussion about planned and ongoing changes to functionality and API changes and additions as well as requests for them.  This is the primary channel for this kind of discussion; related code changes will usually not be applied until they have been discussed here.  This does not include bug reports, which go to xemacs-beta.

xemacs-mule
     is an open mailing list for discussion of International extensions to XEmacs including Mule, XIM, I18n issues, etc, and is not confined to developmental issues. This list is not restricted to English, postings in all languages are welcome.

xemacs-news
     is an open list for discussion and bug reporting for XEmacs.  This mailing list is bi-directionally gatewayed with the USENET newsgroup comp.emacs.xemacs.

xemacs-nt
     is a developers-only mailing list and is intended for people who wish to work actively on the porting of XEmacs to Microsoft Windows NT and Microsoft Windows '95.

xemacs-patches
     is an open, moderated list for submission of patches to the XEmacs distribution and its packages. Anyone may subscribe or submit to xemacs-patches, but all submissions are reviewed by the list moderator before they are distributed to the list. Discussion is not appropriate on xemacs-patches.

xemacs-users-ja
     is an open list for discussion and bug reporting for XEmacs.  Japanese is the preferred language of discussion.  It is not gated to comp.emacs.xemacs or the xemacs list.  For fastest response, bugs not specifically related to Japanese or Mule features should be reported on xemacs-beta (in English).

xemacs-users-ru
     is an open list for discussion and bug reporting for XEmacs.  Russian is the preferred language of discussion.  It is not gated to comp.emacs.xemacs or the xemacs list.  For fastest response, bugs not specifically related to Russian or Mule features should be reported on xemacs-beta (in English).

Q1.4.3: Where are the mailing lists archived?
---------------------------------------------

The archives can be found at http://list-archive.xemacs.org

Q1.4.4: How can I get two instances of info?
--------------------------------------------

Before 21.4, you can't.  The info package does not provide for multiple info buffers.  In 21.4, this should be fixed. #### how?

Q1.4.5: How do I add new Info directories?
------------------------------------------

You use something like:

     (setq Info-directory-list (cons
                                (expand-file-name "~/info")
                                Info-default-directory-list))

David Masterson writes:

     Emacs Info and XEmacs Info do many things differently.  If you're trying to support a number of versions of Emacs, here are some notes to remember:

      1. Emacs Info scans Info-directory-list from right-to-left while XEmacs Info reads it from left-to-right, so append to the correct end of the list.

      2. Use Info-default-directory-list to initialize Info-directory-list if it is available at startup, but not all Emacsen define it.

      3. Emacs Info looks for a standard dir file in each of the directories scanned from #1 and magically concatenates them together.

      4. XEmacs Info looks for a localdir file (which consists of just the menu entries from a dir file) in each of the directories scanned from #1 (except the first), does a simple concatenation of them, and magically attaches the resulting list to the end of the menu in the dir file in the first directory.

     Another alternative is to convert the documentation to HTML with texi2html and read it from a web browser like Lynx or W3.

1.5: Contributing to XEmacs
===========================

Q1.5.1: How do I submit changes to the FAQ?
-------------------------------------------

The FAQ is actively maintained and modified regularly.  All links should be up to date.  Unfortunately, some of the information is out of date -- a situation which the FAQ maintainer is working on.  All submissions are welcome, please e-mail submissions to XEmacs FAQ maintainers.

Please make sure that XEmacs FAQ appears on the Subject: line. If you think you have a better way of answering a question, or think a question should be included, we'd like to hear about it.  Questions and answers included into the FAQ will be edited for spelling and grammar and will be attributed.  Answers appearing without attribution are either from versions of the FAQ dated before May 1996 or are from previous FAQ maintainers.  Answers quoted from Usenet news articles will always be attributed, regardless of the author.

Q1.5.2: How do I become a beta tester?
--------------------------------------

Send an email message to xemacs-beta-request@xemacs.org with the line subscribe in the body of the message.

Be prepared to get your hands dirty, as beta testers are expected to identify problems as best they can.

Q1.5.3: How do I contribute to XEmacs itself?
---------------------------------------------

It depends on the knowledge and time you possess.  If you are able, by all means become a beta tester (see Q1.5.2).  If you are a programmer, try to build XEmacs and see if you can improve it.

Otherwise, you can still help by using XEmacs as your everyday editor (for pre-built binary versions, see Q1.1.2) and reporting bugs you find to the mailing list.

Another area where we need help is the documentation: We need good documentation for building XEmacs and for using it.  This FAQ is a small step in that direction.

Ben Wing ben@xemacs.org writes:

     BTW if you have a wish list of things that you want added, you have to speak up about it!  More specifically, you can do the following if you want a feature added (in increasing order of usefulness):

       * Make a posting about a feature you want added.

       * Become a beta tester and make more postings about those same features.

       * Convince us that you're going to use the features in some cool and useful way.

       * Come up with a clear and well-thought-out API concerning the features.

       * Write the code to implement a feature and send us a patch.

     (not that we're necessarily requiring you to write the code, but we can always hope :)

Q1.5.4: How do I get started developing XEmacs?
-----------------------------------------------

First, get yourself set up under CVS so that you can access the CVS repositories containing the XEmacs sources and the XEmacs packages.

Next, set up your layout.  This is important, as a good layout will facilitate getting things done efficiently, while a bad layout will could lead to disaster, as you can't figure out which code is the most recent, which can be thrown away, etc.  We suggest the following layout: (feel free to make changes)

  * Everything goes under /src/xemacs (use a different directory if you want).  From now, instead of saying /src/xemacs, we use <xsrc-top>, to make it easier in case someone picked a different directory.

  * Package source is in <xsrc-top>/package-src.

  * Installed packages go under <xsrc-top>/xemacs-packages, and <xsrc-top>/mule-packages.

  * A "workspace" is a complete copy of the sources, in which you do work of a particular kind.  Workspaces can be differentiated by which branch of the source tree they extend off of -- usually either the stable or experimental, unless other branches have been created (for example, Ben created a branch for his Mule work because (1) the project was long-term and involved an enormous number of changes, (2) people wanted to be able to look at what his work in progress, and (3) he wanted to be able to check things in and in general use source-code control, since it was a long-term project).  Workspaces are also differentiated in what their purpose is -- general working workspace, workspace for particular projects, workspace keeping the latest copy of the code in one of the branches without mods, etc.

  * Various workspaces are subdirectories under <xsrc-top>, e.g.:

       * <xsrc-top>/working (the workspace you're actively working on, periodically synched up with the latest trunk)

       * <xsrc-top>/stable (for making changes to the stable version of XEmacs, which sits on a branch)

       * <xsrc-top>/unsigned-removal (a workspace for a specific, difficult task that's going to affect lots of source and take a long time, and so best done in its own workspace without the interference of other work you're doing.  Also, you can commit just this one large change, separate from all the other changes).

       * <xsrc-top>/latest (a copy of the latest sources on the trunk, i.e. the experimental version of XEmacs, with no patches in it; either update it periodically, by hand, or set up a cron job to do it automatically).  Set it up so it can be built, and build it so you have a working XEmacs. (Building it might also go into the cron job.)

          This workspace serves a number of purposes:

           1. You always have a recent version of XEmacs you can compare against when something you're working on breaks.  It's true that you can do this with cvs diff, but when you need to do some serious investigation, this method just fails.

           2. You (almost) always have a working, up-to-date executable that can be used when your executable is crashing and you need to keep developing it, or when you need an `xemacs' to build packages, etc.

           3. When creating new workspaces, you can just copy the `latest' workspace using GNU cp -a.  You have all the .elc's built, everything else probably configured, any spare files in place (e.g. some annoying xpm.dll under Windows, etc.).

       * <xsrc-top>/latest-stable/ (equivalent to <xsrc-top>/latest/, but for the Stable branch of XEmacs, rather than the Experimental branch of XEmacs).  This may or may not be necessary depending on how much development you do of the stable branch.

  * <xsrc-top>/xemacsweb is a workspace for working on the XEmacs web site.

  * <xsrc-top>/in-patches for patches received from email and saved to files.

  * <xsrc-top>/out-patches for locally-generated patches to be sent to xemacs-patches@xemacs.org.  Less useful now that the patcher util has been developed.

  * <xsrc-top>/build, for build trees when compiling and testing XEmacs with various configuration options turned off and on.  The scripts in xemacs-builds/ben (see below) can be used to automate building XEmacs workspaces with many different configuration options and automatically filtering out the normal output so that you see only the abnormal output.

  * <xsrc-top>/xemacs-builds, for the xemacs-builds module, which you need to check out separately in CVS.  This contains scripts used for building XEmacs, automating and simplifying using CVS, etc.  Under various people's directories are their own build and other scripts.  The currently most-maintained scripts are under ben/, where there are easily configurable scripts that can be used to easily build any workspace (esp. if you've more or less followed the layout presented above) unattended, with one or more configuration states (there's a pre-determined list of the most useful, but it's easy to change).  The output is filtered and split up in various ways so that you can identify which output came from where, and you can see the output either full or with all "normal" output except occasional status messages filtered so that you only see the abnormal ones.

Q1.5.5: What's the basic layout of the code?
--------------------------------------------

The file configure is a shell script to acclimate XEmacs to the oddities of your processor and operating system.  It will create a file named Makefile (a script for the make program), which helps automate the process of building and installing emacs.  See INSTALL for more detailed information.

The file configure.in is the input used by the autoconf program to construct the configure script.  Since XEmacs has configuration requirements that autoconf can't meet, configure.in uses an unholy marriage of custom-baked configuration code and autoconf macros; it may be wise to avoid rebuilding configure from configure.in when possible.

The file Makefile.in is a template used by configure to create Makefile.

There are several subdirectories:

 1. src holds the C code for XEmacs (the XEmacs Lisp interpreter and its primitives, the redisplay code, and some basic editing functions).

 2. lisp holds the XEmacs Lisp code for XEmacs (most everything else).

 3. lib-src holds the source code for some utility programs for use by or with XEmacs, like movemail and etags.

 4. etc holds miscellaneous architecture-independent data files XEmacs uses, like the tutorial text.  The contents of the lisp, info and man subdirectories are architecture-independent too.

 5. lwlib holds the C code for the X toolkit objects used by XEmacs.

 6. info holds the Info documentation tree for XEmacs.

 7. man holds the source code for the XEmacs online documentation.

 8. nt holds files used compiling XEmacs under Microsoft Windows.

1.6: Politics (XEmacs vs. GNU Emacs)
====================================

Q1.6.1: What is GNU Emacs?
--------------------------

GNU Emacs and XEmacs are related open-source text editors.  Both derive from GNU Emacs version 18; the split between the two happened in 1991 (for comparison, the oldest versions of GNU Emacs date from 1984).  For information on GNU Emacs, see http://www.gnu.org/software/emacs/emacs.html.

Q1.6.2: How does XEmacs differ from GNU Emacs?
----------------------------------------------

For a detailed description of the differences between GNU Emacs and XEmacs and a detailed history of XEmacs, check out the

     NEWS file (http://www.xemacs.org/About/XEmacsVsGNUemacs.html)

User-Visible Editing Features
     XEmacs in general tries hard to conform to exist user-interface standards, and to work "out-of-the-box" without the need for obscure customization changes.  GNU Emacs, particularly version 21, has gotten better about this (in many cases by copying the XEmacs behavior!), but still has some weirdnesses.  For example, the standard method of selecting text using the Shift key works out-of-the-box in XEmacs.

     XEmacs has a built-in toolbar. Four toolbars can actually be configured simultaneously: top, bottom, left, and right toolbars.

     XEmacs has vertical and horizontal scrollbars. Unlike in GNU Emacs 19 (which provides a primitive form of vertical scrollbar), these are true toolkit scrollbars. A look-alike Motif scrollbar is provided for those who don't have Motif. (Even for those who do, the look-alike may be preferable as it is faster.)

     XEmacs has buffer tabs along the top of the frame (although the position can be changed) that make it very easy to switch buffers.

     The menubar under XEmacs is better-designed, with more thought put into it.

     XEmacs can ask questions using popup dialog boxes. Any command executed from a menu will ask yes/no questions with dialog boxes, while commands executed via the keyboard will use the minibuffer.

     XEmacs under MS Windows provides uses the standard file-dialog box for opening and saving files.  Standard menu-accelerator behavior can easily be enabled using the Options menu, and integrates well into the existing keymap.

     XEmacs has (still experimental) support for widgets of various sorts -- buttons, text boxes, sliders, progress bars, etc.  A progress bar is used in font lock to show the progress.

     Experimental support for drag-and-drop protocols is provided from XEmacs 21.

General Platform Support
     If you're running on a machine with audio hardware, you can specify sound files for XEmacs to play instead of the default X beep. See the documentation of the function load-sound-file and the variable sound-alist. XEmacs also supports the network sound protocols NAS and EsounD.

     XEmacs 21 supports database protocols with LISP bindings, currently including Berkeley DB, LDAP, and PostgreSQL (21.2 only).

     XEmacs 20 and 21 support the Canna, Wnn, and SJ3 Japanese input method servers directly, as well as through the X Input Method (XIM) protocol. GNU Emacs 20 supports only the XIM protocol. Both Emacsen support the Quail family of input methods (implemented in LISP) for many languages.

     XEmacs provides support for ToolTalk on systems that have it.

Packaged LISP Libraries
     Many more packages are provided standard with XEmacs than with GNU Emacs 19 or 20.

     XEmacs 21 supports an integrated package management system which uses EFS to download, then automatically install prebuilt LISP libraries. This allows XEmacs users much more straightforward access to the "latest and greatest" version of any given library.

     We are working on a standard method for enabling, disabling and otherwise controlling packages, which should make them very easy to use.

LISP Programming
     From XEmacs 20 on, characters are a separate type. Characters can be converted to integers (and many integers can be converted to characters), but characters are not integers. GNU Emacs 19, XEmacs 19, Mule 2.3 (an extensive patch to GNU Emacs 18.55 and 19.x), and GNU Emacs 20 (incorporating Mule 3 and later Mule 4) represent them as integers.

     From XEmacs 20 on, the buffer is treated as an array of characters, and the representation of buffer text is not exposed to LISP. The GNU Emacs 20 functions like buffer-as-multibyte are not supported.

     In XEmacs, events are first-class objects. GNU Emacs 19 represents them as integers, which obscures the differences between a key gesture and the ancient ASCII code used to represent a particular overlapping subset of them.

     In XEmacs, keymaps are first-class opaque objects. GNU Emacs 19 represents them as complicated combinations of association lists and vectors. If you use the advertised functional interface to manipulation of keymaps, the same code will work in XEmacs, GNU Emacs 18, and GNU Emacs 19; if your code depends on the underlying implementation of keymaps, it will not.

     XEmacs uses "extents" to represent all non-textual aspects of buffers; GNU Emacs 19 uses two distinct objects, "text properties" and "overlays", which divide up the functionality between them. Extents are a superset of the union of the functionality of the two GNU Emacs data types. The full GNU Emacs 19 interface to text properties and overlays is supported in XEmacs (with extents being the underlying representation).

     Extents can be made to be copied into strings, and then restored, by kill and yank. Thus, one can specify this behavior on either "extents" or "text properties", whereas in GNU Emacs 19 text properties always have this behavior and overlays never do.

Window System Programming Interface
     XEmacs uses the MIT "Xt" toolkit instead of raw Xlib calls, which makes it be a more well-behaved X citizen (and also improves portability). A result of this is that it is possible to include other Xt "Widgets" in the XEmacs window. Also, XEmacs understands the standard Xt command-line arguments.

     XEmacs supports Motif applications, generic Xt (e.g. Athena) applications, and raw Xlib applications. An XEmacs variant which supports GTK+ is available (integration as an option in the XEmacs mainline is planned for XEmacs 22), although code to take advantage of the support is as yet scarce.

     An XEmacs frame can be placed within an "external client widget" managed by another application. This allows an application to use an XEmacs frame as its text pane rather than the standard Text widget that is provided with Motif or Athena.

Community Participation
     Joining the XEmacs development team is simple. Mail to XEmacs Developers, and you're in! (If you want to be, of course. You're also welcome to just post development-related questions and bug reports.) The GNU Emacs development team and internal mailing lists are still by invitation only.

     The "bleeding edge" of mainline XEmacs development is available by anonymous CVS as are some subsidiary branches (check out the xemacs-gtk module for the latest in GUI features!)

     Development and maintenance of Lisp libraries is separated from the core editor development at a fairly low level. This provides better modularization and a better division of responsibility between external library maintainers and the XEmacs core development team. Even for packages the size of Gnus, XEmacs users normally have access to a pre-built version within a few weeks of a major release, and minor updates often within days.

     CVS commit authority is broadly dispersed. Recognized maintainers of LISP libraries who are willing to maintain XEmacs packaged versions automatically qualify for CVS accounts for their packages.

Q1.6.3: How much does XEmacs differ?
------------------------------------

RMS has asserted at times that XEmacs is merely a "patch" on top of GNU Emacs (see Q1.6.4).  In fact, probably not more than 5% of the code, if that, remains unchanged, and nearly 14 years of work has gone into XEmacs at this point. (GNU Emacs itself is only than 20 years old, and thus XEmacs has existed as a separate product for over 2/3 of the lifespan of GNU Emacs.) As a point of comparison, XEmacs 21.5 has perhaps 65,000 more lines of C code than GNU Emacs 21.2.

However, the XEmacs developers strive to keep their code compatible with GNU Emacs, especially on the Lisp level.  Much effort goes into "synching" the XEmacs Elisp code with recent GNU Emacs releases so as to benefit from GNU Emacs development work. (In contrast, almost no code from XEmacs has made it into GNU Emacs, and in fact the GNU Emacs developers are instructed by RMS not to even look at XEmacs source code! This stems from self-imposed licensing restrictions on the part of GNU Emacs -- and almost certainly out of hostility, as well.)

Q1.6.4: Is XEmacs "GNU"?
------------------------

RMS insists on the term "GNU XEmacs" and maintains that

     XEmacs is GNU software because it's a modified version of a GNU program. And it is GNU software because the FSF is the copyright holder for most of it, and therefore the legal responsibility for protecting its free status falls on us whether we want it or not. This is why the term "GNU XEmacs" is legitimate.

In fact, FSF is not the copyright holder for most of the code, as very little unmodified FSF code remains (see Q1.6.3).

Furthermore, RMS's assertion that XEmacs is "GNU" seems rather bizarre to the XEmacs developers given RMS's hostility and general lack of interest in cooperation.  "GNU" software in general is part of the GNU Project, is distributed by it on their FTP site, and receives support (or at least cooperation), as well as implicit endorsement, from it. The GNU Project, however, has never supported XEmacs and never distributed XEmacs, and RMS's hostility is the farthest thing possible from an endorsement.  In fact, the GNU Project distributes a number of non-GNU software projects on the FSF web site, but again XEmacs is not one of them.

Q1.6.5: What is the correct way to refer to XEmacs and GNU Emacs?
-----------------------------------------------------------------

Unfortunately even the naming of these two applications has become politicized.  Much of this stems from RMS, who has a history of politicizing similar issues. (Compare the controversy over "Lignux" and "GNU/Linux".) We would prefer that the terms "XEmacs" and "GNU Emacs" be used, which are neutral and acceptable to most people.  RMS, however, is not willing to accept these terms.  He insists that, if his product is called "GNU Emacs", then ours must be called "GNU XEmacs". (For our opinion of this term, see Q1.6.4.) On the other hand, if our product is to be called "XEmacs", as we prefer, then his product must simply be called "Emacs".  The intent of this seems clear: RMS wants to make sure the names reflect his view that his version is the "real" Emacs and ours is merely a derivative, second-class product (see Q1.6.3).

The XEmacs developers hope that you will use the neutral terms "XEmacs" and "GNU Emacs" for these two specific products. "Emacs", on the other hand, is a generic term for a class of programmable text editors with a similar look-and-feel, and usually a Lisp-based extension language.  These trace themselves back to early editors such as EINE, ZWEI, ZMACS and Multics Emacs. See A History of Emacs (XEmacs Internals Manual).

We also call upon RMS, in the spirit of furthering cooperation, to stop politicizing this issue and use the neutral terms "XEmacs" and "GNU Emacs".  We have already acceded to RMS' wishes in this respect, and we expect him to do the same. (In the past, the XEmacs developers often used the terms "FSF Emacs" or "FSFmacs" or "RMSmacs" in reference to GNU Emacs; these terms were apparently modeled after RMS' own usage of "Gosmacs" and "Gosling Emacs" in reference to Unipress Emacs, produced by James Gosling.  RMS, however, considers such terms to be insulting, so we refrain from using them as much as possible in preference to GNU Emacs.)

Q1.6.6: Why haven't XEmacs and GNU Emacs merged?
------------------------------------------------

There are currently irreconcilable differences in the views about technical, programming, design, organizational and legal matters between Richard Stallman (RMS), the author and leader of the GNU Emacs project, and the XEmacs development team which provide little hope for a merge to take place in the short-term future.  There have been repeated attempts at merging by all of the major XEmacs developers, starting from the early days of Lucid Emacs (in 1991), but they have all failed.  RMS has very strong views about how GNU Emacs should be structured and how his project should be run, and during the repeated merge efforts has never demonstrated any realistic interest in sufficiently compromising or ceding control to allow a middle ground to be found.  The basic problem seems to be the very different goals of RMS and the XEmacs project.  The primary goals of the XEmacs project are technical and organizational -- we want to create the best editor possible, and to make it as easy as possible for people around the world to contribute.  The primary goals of RMS, on the other hand, are political, and GNU Emacs, and any potential merge efforts with XEmacs, are strictly subservient to these goals.  In fact, in many ways RMS sees GNU Emacs as the "poster child" of his aims, the one program in the GNU project that above all others must set an example to the world. (This has to do with the fact that GNU Emacs was the first program in the GNU project, and the only one that he is still personally involved with on a day-to-day basis.)  Given his goals, his position is completely reasonable -- but unfortunately, makes any merge impossible.

From the XEmacs perspective, the most intractable issues appear to be legal and organizational, specifically:

  * RMS requires "legal papers" to be signed for all contributions of code to GNU Emacs over 10 lines or so, transferring the copyright and all legal rights to the code to the Free Software Foundation.  XEmacs does not and has never required this, since it has the practical effect of discouraging individual and in particular corporate contributions -- corporations will almost never sign away their legal rights to code since it makes it impossible to reuse the code in any product that whose license is not compatible with the GNU General Public License. Since RMS has shown no inclination to compromise on this issue, a merge would require that most of the existing XEmacs code would need to be thrown away and rewritten -- something the XEmacs developers are understandably reluctant to do.

  * A repeated stumbling block in the merge talks has been the issue of organizational control over the resulting product.  RMS has made it clear that he intends to have final say over design issues in a merged Emacs.  Unfortunately, RMS and the XEmacs developers have repeatedly clashed over design decisions, and RMS' insistence on getting his way in such disagreements was the very reason for the split in the first place.  This same issue has come up again and again in merge talks and we have never been able to come to a satisfactory resolution.  To the extent that RMS is willing to compromise at all, it appears to be of a purely political rather than technical nature -- "If we support this feature of yours, we also get to support this other feature of mine." The XEmacs developers cannot see how such a process would lead to anything but a mess of incompatible things hodgepodged together.

  * Because of the years of separate development, distinct and incompatible interfaces have developed and merging would be extremely difficult even with the above non-technical issues resolved.  The problem has been exacerbated by the issue of legal papers -- because XEmacs code is not "kosher" from RMS' perspective, he discourages developers from even looking at it out of legal concerns.  Although it is still possible to read the XEmacs documentation and run the program, the practical effect of this prohibition has been to strongly discourage code-sharing and cooperative development -- although a great deal of GNU Emacs code has been incorporated into XEmacs, practically none has gone the other direction.

If you have a comment to add regarding the merge, it is a good idea to avoid posting to the newsgroups, because of the very heated flamewars that often result.  Mail your questions to xemacs-beta@xemacs.org and emacs-devel@gnu.org.

1.7: External Packages
======================

Q1.7.1: What is the package system?
-----------------------------------

In order to reduce the size and increase the maintainability of XEmacs, the majority of the Elisp packages that came with previous releases have been unbundled.  They have been replaced by the package system.  Each elisp add-on (or groups of them when they are small) now comes in its own tarball that contains a small search hierarchy.

You select just the ones you need.  Install them by untarring them into the right place.  On startup XEmacs will find them, set up the load path correctly, install autoloads, etc, etc.

See Q2.1.1, for more info on how to download and install the packages.

Q1.7.2: Which external packages are there?
------------------------------------------

Normal Packages
---------------

A very broad collection of elisp packages.

Sun
     Support for Sparcworks.

ada
     Ada language support.

apel
     A Portable Emacs Library.  Used by XEmacs MIME support.

auctex
     Basic TeX/LaTeX support.

bbdb
     The Big Brother Data Base: a rolodex-like database program.

build
     Build XEmacs from within (UNIX, Windows).

c-support
     Basic single-file add-ons for editing C code.

calc
     Emacs calculator.

calendar
     Calendar and diary support.

cc-mode
     C, C++, Objective-C, Java, CORBA IDL, Pike and AWK language support.

clearcase
     New Clearcase Version Control for XEmacs (UNIX, Windows).

clearcase
     Support for the Clearcase version control system.

cookie
     "Fortune cookie"-style messages. Includes Spook (suspicious phrases) and Yow (Zippy quotes).

crisp
     Crisp/Brief emulation.

debug
     GUD, gdb, dbx debugging support.

dictionary
     Interface to RFC2229 dictionary servers.

dired
     The DIRectory EDitor is for manipulating, and running commands on files in a directory.

docbookide
     DocBook editing support.

ecb
     Emacs source code browser.

ecrypto
     Crypto functionality in Emacs Lisp.

edebug
     An Emacs Lisp debugger.

ediff
     Interface over GNU patch.

edit-utils
     Miscellaneous editor extensions, you probably need this.

edt
     DEC EDIT/EDT emulation.

efs
     Treat files on remote systems the same as local files.

eieio
     Enhanced Implementation of Emacs Interpreted Objects.

elib
     Portable Emacs Lisp utilities library.

emerge
     Another interface over GNU patch.

erc
     ERC is an Emacs InternetRelayChat client.

escreen
     Multiple editing sessions withing a single frame (like screen).

eshell
     Command shell implemented entirely in Emacs Lisp.

ess
     ESS: Emacs Speaks Statistics.

eterm
     Terminal emulation.

eudc
     Emacs Unified Directory Client (LDAP, PH).

footnote
     Footnoting in mail message editing modes.

forms
     Forms editing support (obsolete, use Widget instead).

fortran-modes
     Fortran support.

fortran-modes
     Fortran language support.

frame-icon
     Set up mode-specific icons for each frame under XEmacs.

fsf-compat
     GNU Emacs compatibility files.

games
     Tetris, Sokoban, and Snake.

general-docs
     General documentation.  Presently, empty.

gnats
     XEmacs bug reports.

gnus
     The Gnus Newsreader and Mailreader.

haskell-mode
     Haskell editing support.

hm--html-menus
     HTML editing.

hyperbole
     Hyperbole: The Everyday Info Manager.

ibuffer
     Advanced replacement for buffer-menu.

idlwave
     Editing and Shell mode for the Interactive Data Language.

igrep
     Enhanced front-end for Grep.

ilisp
     Front-end for interacting with Inferior Lisp (external lisps).

ispell
     Spell-checking with GNU ispell.

jde
     Integrated Development Environment for Java.

liece
     IRC (Internet Relay Chat) client for Emacs.  Note, this package is deprecated and will be removed, use riece instead.

mail-lib
     Fundamental lisp files for providing email support.

mailcrypt
     Support for messaging encryption with PGP.

mew
     Messaging in an Emacs World; a MIME-based email program.

mh-e
     The XEmacs Interface to the MH Mail System.

mine
     Elisp implementation of the game 'Minehunt'.

misc-games
     Other amusements and diversions.

mmm-mode
     Support for Multiple Major Modes within a single buffer.

net-utils
     Miscellaneous Networking Utilities.

ocaml
     Objective Caml editing support.

oo-browser
     OO-Browser: The Multi-Language Object-Oriented Code Browser.

ocaml
     Objective Caml editing support.

os-utils
     Miscellaneous single-file O/S utilities, for printing, archiving, compression, remote shells, etc.

pc
     PC style interface emulation.

pcl-cvs
     CVS frontend.

pcomplete
     Provides programmatic completion.

perl-modes
     Perl support.

pgg
     Emacs interface to various PGP implementations.

prog-modes
     Support for various programming languages.

ps-print
     Printing functions and utilities.

psgml
     Validated HTML/SGML editing.

psgml-dtds
     A collection of DTDs for psgml.  Note that this package is deprecated and will be removed in the future, most likely Q2/2003.  Instead of using this, you should install needed DTDs yourself.

python-modes
     Python language support.

reftex
     Emacs support for LaTeX cross-references, citations.

riece
     IRC (Internet Relay Chat) client for Emacs.

rmail
     An obsolete Emacs mailer.  If you do not already use it don't start.

ruby-modes
     Ruby support.

sasl
     Simple Authentication and Security Layer (SASL) library.

scheme
     Front-end support for Inferior Scheme.

semantic
     Semantic bovinator (Yacc/Lex for XEmacs). Includes Senator.

sgml
     SGML/Linuxdoc-SGML editing.

sh-script
     Support for editing shell scripts.

sieve
     Manage Sieve email filtering scripts.

slider
     User interface tool.

sml-mode
     SML editing support.

sounds-au
     XEmacs Sun sound files.

sounds-wav
     XEmacs Microsoft sound files.

speedbar
     Provides a separate frame with convenient references.

strokes
     Mouse enhancement utility.

supercite
     An Emacs citation tool for News & Mail messages.

texinfo
     XEmacs TeXinfo support.

text-modes
     Miscellaneous support for editing text files.

textools
     Miscellaneous TeX support.

time
     Display time & date on the modeline.

tm
     Emacs MIME support. Not needed for gnus >= 5.8.0.

tooltalk
     Support for building with Tooltalk.

tpu
     DEC EDIT/TPU support.

tramp
     Remote shell-based file editing.  This is similar to EFS or Ange-FTP, but works with rsh/ssh and rcp/scp.

vc
     Version Control for Free systems.

vc-cc
     Version Control for ClearCase (UnFree) systems.

vhdl
     Support for VHDL.

view-process
     A Unix process browsing tool.

viper
     VI emulation support.

vm
     An Emacs mailer.

w3
     A Web browser.

x-symbol
     Semi WYSIWYG for LaTeX, HTML, etc, using additional fonts.

xemacs-base
     Fundamental XEmacs support, you almost certainly need this.

xemacs-devel
     XEmacs Lisp developer support.  This package contains utilities for supporting Lisp development.  It is a single-file package so it may be tailored.

xlib
     Emacs interface to X server.

xslide
     XSL editing support.

xslt-process
     A minor mode for (X)Emacs which allows running an XSLT processor on a buffer.

xwem
     X Emacs Window Manager.

zenirc
     ZENIRC IRC Client.

Mule Support (mule)
-------------------

MULti-lingual Enhancement.  Support for world scripts such as Latin, Arabic, Cyrillic, Chinese, Japanese, Greek, Hebrew etc. To use these packages your XEmacs must be compiled with Mule support.

edict
     MULE: Lisp Interface to EDICT, Kanji Dictionary.

egg-its
     MULE: Wnn (4.2 and 6) support.  SJ3 support.

latin-unity
     MULE: find single ISO 8859 character set to encode a buffer.

latin-unity
     Unify character sets in a buffer. When characters belong to disjoint character sets, this attempts to translate the characters so that they belong to one character set. If the buffer coding system is not sufficient, this suggests different coding systems.

leim
     MULE: Quail.  All non-English and non-Japanese language support.

locale
     MULE: Localized menubars and localized splash screens.

lookup
     Dictionary support. (This isn't an English dictionary program)

mule-base
     MULE: Basic Mule support, required for building with Mule.

mule-ucs
     MULE: Extended coding systems (including Unicode) for XEmacs.

mule-ucs
     Extended coding systems (including Unicode) for XEmacs.

skk
     Another Japanese Language Input Method.  Can be used without a separate process running as a dictionary server.

Q1.7.3: Do I need to have the packages to run XEmacs?
-----------------------------------------------------

Strictly speaking, no.  XEmacs will build and install just fine without any packages installed.  However, only the most basic editing functions will be available with no packages installed, so installing packages is an essential part of making your installed XEmacs _useful_.

Q1.7.4: Is there a way to find which package has particular functionality?
--------------------------------------------------------------------------

If you want to find out which package contains the functionality you are looking for, use M-x package-get-package-provider, and give it a symbol that is likely to be in that package.

For example, if some code you want to use has a (require 'thingatpt) in it:

     	M-x package-get-package-provider RET thingatpt RET

which will return something like: (fsf-compat "1.08").

1.8: Internationalization
=========================

Q1.8.1: What is the status of internationalization support aka MULE (including Asian language support)?
-------------------------------------------------------------------------------------------------------

Both the stable and development versions of XEmacs include internationalization support (aka MULE).  MULE currently (21.4) works on UNIX and Linux systems.  It is possible to build with MULE on Windows systems, but if you really need MULE on Windows, it is recommended that you build and use the development (21.5) version, and deal with the instability of the development tree.  Binaries compiled without MULE support run faster than MULE capable XEmacsen.

Q1.8.2: How can I help with internationalization?
-------------------------------------------------

If you would like to help, you may want to join the xemacs-mule@xemacs.org mailing list.  Especially needed are people who speak/write languages other than English, who are willing to use XEmacs/MULE regularly, and have some experience with Elisp.

Translations of the TUTORIAL and man page are welcome, and XEmacs does support multilingual menus, but we have few current translations.

See How do I become a Beta Tester?.

Q1.8.3: How do I type non-ASCII characters?
-------------------------------------------

See How can you type in special characters in XEmacs?, in part 3 of this FAQ, for some simple methods that also work in non-MULE builds of XEmacs (but only for one-octet coded character sets, and mostly for ISO 8859/1).  Many of the methods available for Cyrillic (see How about Cyrillic modes?) work without MULE.  MULE has more general capabilities.  See Please explain the various input methods in MULE/XEmacs.

See How do I display non-ASCII characters?, which covers display of non-ASCII characters.

Q1.8.4: Can XEmacs messages come out in a different language?
-------------------------------------------------------------

The message-catalog support was written but is badly bit-rotted.  XEmacs 20 and 21 did not support it, and early releases of XEmacs 22 will not either.

However, menubar localization does work.  To enable it, add to your Emacs file entries like this:

     Emacs*XlwMenu.resourceLabels:                   True
     Emacs*XlwMenu.file.labelString:                 Fichier
     Emacs*XlwMenu.openInOtherWindow.labelString: 	In anderem Fenster oeffnen

The name of the resource is derived from the non-localized entry by removing punctuation and capitalizing as above.

Q1.8.5: Please explain the various input methods in MULE/XEmacs
---------------------------------------------------------------

Mule supports a wide variety of input methods.  There are three basic classes: Lisp implementations, generic platform support, and library interfaces.

Lisp implementations include Quail, which provides table-driven input methods for almost all the character sets that Mule supports (including all of the ISO 8859 family, the Indic languages, Thai, and so on), and SKK, for Japanese.  (SKK also supports an interface to an external "dictionary server" process.)  Quail supports both typical "dead-key" methods (eg, in the "latin-1-prefix" method, " a produces ä, LATIN SMALL LETTER A WITH DIAERESIS), and the complex dictionary-based phonetic methods used for Asian ideographic languages like Chinese.

Lisp implementations can be less powerful (but they are not perceptibly inefficient), and of course are not portable to non-Emacs applications. The incompatibility can be very annoying.  On the other hand, they require no special platform support or external libraries, so if you can display the characters, Mule can input them for you and you can edit, anywhere.

Generic platform support is currently limited to the X Input Method (XIM) framework, although support for MSIME (for MS Windows) is planned, and IIIMF (Sun's Internet-Intranet Input Method Framework) support is extremely desirable.  XIM is enabled at build time by use of the --with-xim flag to configure.  For use of XIM, see your platform documentation.  However, normally the input method you use is specified via the LANG and XMODIFIERS environment variables.

Of course, input skills are portable across most applications.  However, especially in modern GUI systems the habit of using bucky bits has fallen into sad disuse, and many XIM systems are poorly configured for use with Emacs.  For example, the kinput2 input manager (a separate process providing an interface between Japanese dictionary servers such as Canna and Wnn, and the application) tends to gobble up keystrokes generating Meta characters.  This means that to edit while using an XIM input method, you must toggle the input method off every time you want to use M-f.  Your mileage may vary.

Library interfaces are most common for Japanese, although Wnn supports Chinese (traditional and simplified) and Korean.  There are Chinese and Korean input servers available, but we do not know of any patches for XEmacs to use them directly.  You can use them via IM-enabled terminals, by manipulating the terminal coding systems.  We describe only the Japanese-oriented systems here.  The advantage of these systems is that they are very powerful, and on platforms where they are available there is typically a wide range of applications that support them.  Thus your input skills are portable across applications.

Mule provides built-in interfaces to the following input methods: Wnn4, Wnn6, Canna, and SJ3.  These can be configured at build time.  There are patches available (no URL, sorry) to support the SKK server, as well. Wnn and SJ3 use the egg user interface.  The interface for Canna is specialized to Canna.

Wnn supports Japanese, Chinese and Korean. It is made by OMRON and Kyôto University. It is a powerful and complex system.  Wnn4 is free and Wnn6 is not.  Wnn uses grammatical hints and probability of word association, so in principle Wnn can be cleverer than other methods.

Canna, made by NEC, supports only Japanese.  It is a simple and powerful system. Canna uses only grammar, but its grammar and dictionary are quite sophisticated.  So for standard modern Japanese, Canna seems cleverer than Wnn4. In addition, the UNIX version of Canna is free (now there is a Microsoft Windows version).

SJ3, by Sony, supports only Japanese.

Egg consists of following parts:

 1. Input character Translation System (ITS) layer. It translates ASCII inputs to Kana/PinYin/Hangul characters.

 2. Kana/PinYin/Hangul to Kanji transfer layer. The interface layer to network Kana-Kanji server (Wnn and Sj3).

These input methods are modal.  They have a raw (alphabet) mode, a phonetic input mode, and Kana-Kanji transfer mode.  However there are mode-less input methods for Egg and Canna.  boiled-egg is a mode-less input method running on Egg.  For Canna, canna.el has a tiny boiled-egg-like command, (canna-boil), and there are some boiled-egg-like utilities.

Much of this information was provided by MORIOKA Tomohiko.

Q1.8.6: How do I portably code for MULE/XEmacs?
-----------------------------------------------

MULE has evolved rapidly over the last few years, and the original third party patch (for GNU Emacs 19), GNU Emacs 20+, and XEmacs 20+ have quite different implementations.  The APIs also vary although recent versions of XEmacs have tended to converge to the GNU Emacs standard.

MULE implementations are going to continue to evolve.  Both GNU Emacs and XEmacs are working hard on Unicode support, which will involve new APIs and probably variations on old ones.  For XEmacs 22, the old ISO 2022-based system for recognizing encodings will be replaced by a much more flexible system, which should improve accuracy of automatic coding detections, but will also involve new APIs.

MORIOKA Tomohiko writes:

     The application implementor must write separate code for these mule variants.  [Please don't hesitate to report these variants to us; they are not, strictly speaking, bugs, but they give third-party developers the same kind of creepy-crawly feeling.  We'll do what we can. -- Ed.]

     MULE and the next version of Emacs are similar but the symbols are very different---requiring separate code as well.

     Namely we must support 3 kinds of mule variants and 4 or 5 or 6 kinds of emacs variants... (;_;) I'm shocked, so I wrote a wrapper package called emu to provide a common interface.  [There is an XEmacs package of APEL which provides much more comprehensive coverage.  Be careful, however; APEL has problems of its own. -- Ed.]

     I have the following suggestions about dealing with mule variants:

       * (featurep 'mule) t on all mule variants

       * (boundp 'MULE) is t on only MULE.  Maybe the next version of Emacs will not have this symbol.

       * MULE has a variable mule-version.  Perhaps the next version of Emacs will have this variable as well.

     Following is a sample to distinguish mule variants:

          (if (featurep 'mule)
              (cond ((boundp 'MULE)
                     ;; for original Mule
                     )
                    ((string-match "XEmacs" emacs-version)
                     ;; for XEmacs with Mule
                     )
                    (t
                     ;; for next version of Emacs
                     ))
            ;; for old emacs variants
            )

Q1.8.7: How about Cyrillic modes?
---------------------------------

Ilya Zakharevich writes:

     There is a cyrillic mode in the file mysetup.zip in ftp://ftp.math.ohio-state.edu/pub/users/ilya/emacs/.  This is a modification to Valery Alexeev's russian.el which can be obtained from

http://www.math.uga.edu/~valery/russian.el.

Dima Barsky writes:

     There is another cyrillic mode for both GNU Emacs and XEmacs by Dmitrii (Mitya) Manin at http://kulichki-lat.rambler.ru/centrolit/manin/cyr.el.

Rebecca Ore writes:

     The fullest resource I found on Russian language use (in and out of XEmacs) is http://www.ibiblio.org/sergei/Software/Software.html

Q1.8.8: Does XEmacs support Unicode?
------------------------------------

To get Unicode support, you need a Mule-enabled XEmacs.

21.5 has internal support for Unicode and supports it fully, although we don't yet use it as the internal encoding.

21.4 supports Unicode partially -- as an external encoding for files, processes, and terminals, but without font support.  See How does XEmacs display Unicode?.  To get Unicode support in 21.4, install Mule-UCS from packages in the usual way, and put

     (require 'un-define)
     (set-coding-priority-list '(utf-8))
     (set-coding-category-system 'utf-8 'utf-8)

in your init file to enable the UTF-8 coding system.  You may wish to view the documentation of set-coding-priority-list if you find that files that are not UTF-8 are being mis-recognized as UTF-8.

Install standard national fonts (not Unicode fonts) for all character sets you use.  See How does XEmacs display Unicode??.

Mule-UCS also supports 16-bit forms of Unicode (UTF-16).  It does not support 31-bit forms of Unicode (UTF-32 or UCS-4).

Q1.8.9: How does XEmacs display Unicode?
----------------------------------------

Mule doesn't have a Unicode charset internally, so there's nothing to bind a Unicode registry to.  It would not be straightforward to create, either, because Unicode is not ISO 2022-compatible.  You'd have to translate it to multiple 96x96 pages.

This means that Mule-UCS uses ordinary national fonts for display.  This is not really a problem, except for those languages that use the Unified Han characters.  The problem here is that Mule-UCS maps from Unicode code points to national character sets in a deterministic way.  By default, this means that Japanese fonts are tried first, then Chinese, then Korean.  To change the priority ordering, use the command `un-define-change-charset-order'.

It also means you can't use Unicode fonts directly, at least not without extreme hackery.  You can run -nw with (set-terminal-coding-system 'utf-8) if you really want a Unicode font for some reason.

Real Unicode support will be introduced in XEmacs 22.0.

2 Installation and Troubleshooting
**********************************

This is part 2 of the XEmacs Frequently Asked Questions list.  This section is devoted to Installation, Maintenance and Troubleshooting.

2.0: Installation (General)
===========================

Q2.0.1: How do I build and install XEmacs?
------------------------------------------

See the file etc/NEWS for information on new features and other user-visible changes since the last version of XEmacs.

The file INSTALL in the top-level directory says how to bring up XEmacs on Unix and Cygwin, once you have loaded the entire subtree of this directory.

See the file nt/README for instructions on building XEmacs for Microsoft Windows.

See Q2.1.1, for the installation of (essential) add on packages.

Q2.0.2: Where do I find external libraries?
-------------------------------------------

All external libraries used by XEmacs can be found on the XEmacs web site http://www.xemacs.org/Download/optLibs.html.

The library versions available here are known to work with XEmacs. (Newer versions will probably work as well but we can't guarantee it.) We try to keep the libraries up-to-date but may not always succeed. Check the above page for the canonical locations of the external libraries, allowing you to download the latest, bleeding-edge versions.

Q2.0.3: How do I specify the paths that XEmacs uses for finding files?
----------------------------------------------------------------------

You can specify what paths to use by using a number of different flags when running configure.  See the section MAKE VARIABLES in the top-level file INSTALL in the XEmacs distribution for a listing of those flags.

Most of the time, however, the simplest fix is: do not specify paths as you might for GNU Emacs.  XEmacs can generally determine the necessary paths dynamically at run time.  The only path that generally needs to be specified is the root directory to install into.  That can be specified by passing the --prefix flag to configure.  For a description of the XEmacs install tree, please consult the NEWS file.

Q2.0.4: Running XEmacs without installing
-----------------------------------------

How can I just try XEmacs without installing it?

XEmacs will run in place without requiring installation and copying of the Lisp directories, and without having to specify a special build-time flag.  It's the copying of the Lisp directories that requires so much space.  XEmacs is largely written in Lisp.

A good method is to make a shell alias for xemacs:

     alias xemacs=/src/xemacs-21.5/src/xemacs

(You will obviously use whatever directory you downloaded the source tree to instead of /src/xemacs-21.5).

This will let you run XEmacs without massive copying.

Q2.0.5: XEmacs is too big
-------------------------

The space required by the installation directories can be reduced dramatically if desired.  Gzip all the .el files.  Remove all the packages you'll never want to use.  Remove the TexInfo manuals. Remove the Info (and use just hardcopy versions of the manual).  Remove most of the stuff in etc.  Remove or gzip all the source code.  Gzip or remove the C source code.  Configure it so that copies are not made of the support lisp.

These are all Emacs Lisp source code and bytecompiled object code.  You may safely gzip everything named *.el here.  You may remove any package you don't use.  Nothing bad will happen if you delete a package that you do not use.  You must be sure you do not use it though, so be conservative at first.

Any package with the possible exceptions of xemacs-base, and EFS are candidates for removal.  Ask yourself, Do I ever want to use this package?  If the answer is no, then it is a candidate for removal.

First, gzip all the .el files.  Then go about package by package and start gzipping the .elc files.  Then run XEmacs and do whatever it is you normally do.  If nothing bad happens, then remove the package.  You can remove a package via the PUI interface (M-x pui-list-packages, then press d to mark the packages you wish to delete, and then x to delete them.

Another method is to do M-x package-get-delete-package.

2.1: Package Installation
=========================

Q2.1.1: How do I install the packages?
--------------------------------------

There are three ways to install the packages.

 1. Manually, all at once, using the 'Sumo Tarball'.

 2. Manually, using individual package tarballs.

 3. Automatically, using the package tools from XEmacs.

If you don't want to mess with the packages, it is easiest to just grab them manually, all at once. (For the other two ways, see Q2.1.2, and see Q2.1.3.) Download the file

xemacs-sumo.tar.gz

For an XEmacs compiled with Mule you also need

xemacs-mule-sumo.tar.gz

These are in the packages directory on your XEmacs mirror archive: ftp://ftp.xemacs.org/pub/xemacs/packages or its mirrors.  N.B. They are called 'Sumo Tarballs' for good reason. They are currently about 19MB and 4.5MB (gzipped) respectively.

Install them on Unix and Mac OS X using the shell/Terminal command

cd $prefix/lib/xemacs ; gunzip -c <tarballname> | tar xf -

Where $prefix is what you gave to the --prefix flag to configure, and defaults to /usr/local.

If you have GNU tar you can use:

cd $prefix/lib/xemacs ; tar zxvf <tarballname>

If you have the packages somewhere nonstandard and don't want to bother with $prefix (for example, you're a developer and are compiling the packages yourself, and want your own private copy of everything), you can also directly specify this using configure.  To do this with 21.5 and above use the --with-package-prefix parameter to specify the directory under which you untarred the above tarballs. Under 21.4 and previous you need to use --package-path.  Using these options looks something like this:

        configure --package-path="~/.xemacs::/src/xemacs/site-packages:/src/xemacs/xemacs-packages:/src/xemacs/mule-packages" ...

Under Windows, you need to place the above tar.gz files in the directory specified using the PACKAGE_PREFIX value in nt/config.inc and by default is \Program Files\XEmacs. (To untar a tar.gz file you will need to use a utility such as WinZip, unless you have Cygwin or a similar environment installed, in which case the above Unix shell command should work fine.) If you want the packages somewhere else, just change PACKAGE_PREFIX.

Note that XEmacs finds the packages automatically anywhere underneath the directory tree where it expects to find the packages.  All you need to do is put stuff there; you don't need to run any program to tell XEmacs to find the packges, or do anything of that sort.

However, XEmacs will only notice newly installed packages when it starts up, so you will have to restart if you are already running XEmacs.

For more details, see Startup Paths (the XEmacs User's Manual), and see Packages (the XEmacs User's Manual).

As the Sumo tarballs are not regenerated as often as the individual packages, it is recommended that you use the automatic package tools afterwards to pick up any recent updates.

NOTE: For detailed information about how the package hierarchies work, see Package Overview (the XEmacs Lisp Reference Manual).

Q2.1.2: Can I install the packages individually?
------------------------------------------------

Yes, you can download individual packages from the FTP site (see Q2.1.1).  Since packages are automatically noticed at startup, you just have to put them in the right place.

Note: If you are upgrading packages already installed, it's best to remove the old package first (see Q2.1.4).

For example if we are installing the xemacs-base package (version 1.48):

        mkdir $prefix/lib/xemacs/xemacs-packages RET # if it does not exist yet
        cd $prefix/lib/xemacs/xemacs-packages RET
        gunzip -c /path/to/xemacs-base-1.48-pkg.tar.gz | tar xvf - RET

Or if you have GNU tar, the last step can be:

        tar zxvf /path/to/xemacs-base-1.48-pkg.tar.gz RET

For MULE related packages, it is best to untar into the mule-packages hierarchy, i.e. for the mule-base package, version 1.37:

        mkdir $prefix/lib/xemacs/mule-packages RET # if it does not exist yet
        cd $prefix/lib/xemacs/mule-packages RET
        gunzip -c /path/to/mule-base-1.37-pkg.tar.gz | tar xvf - RET

Or if you have GNU tar, the last step can be:

        tar zxvf /path/to/mule-base-1.37-pkg.tar.gz RET

Q2.1.3: Can I install the packages automatically?
-------------------------------------------------

XEmacs comes with some tools to make the periodic updating and installing easier. It will notice if new packages or versions are available and will fetch them from the FTP site.

Unfortunately this requires that a few packages are already in place. You will have to install them by hand as above or use a SUMO tarball. This requirement will hopefully go away in the future. The packages you need are:

        efs          - To fetch the files from the FTP site or mirrors.
        xemacs-base  - Needed by efs.

and optionally:

        mailcrypt    - For PGP verification of the package-index file.

After installing these by hand, fire up XEmacs and follow these steps.

 1. Choose a download site.

       * via menu: Tools -> Packages -> Set Download Site

       * via keyb: M-x customize-variable RET package-get-remote RET (put in the details of remote host and directory)

     If the package tarballs _AND_ the package-index file are in a local directory, you can: M-x pui-set-local-package-get-directory RET

 2. Obtain a list of packages and display the list in a buffer named "*Packages*".

       * menu: Tools -> Packages -> List & Install

       * keyb: M-x pui-list-packages RET

     XEmacs will now connect to the remote site and download the latest package-index file.

     The resulting buffer, "*Packages*" has brief instructions at the end of the buffer.

 3. Choose the packages you wish to install.

       * mouse: Click button 2 on the package name.

       * keyb: RET on the package name

 4. Make sure you have everything you need.

       * menu: Packages -> Add Required

       * keyb: r

     XEmacs will now search for packages that are required by the ones that you have chosen to install and offer to select those packages also.

     For novices and gurus alike, this step can save your bacon. It's easy to forget to install a critical package.

 5. Download and install the packages.

       * menu: Packages -> Install/Remove Selected

       * keyb: x

Q2.1.4: Can I upgrade or remove packages?
-----------------------------------------

As the exact files and their locations contained in a package may change it is recommended to remove a package first before installing a new version. In order to facilitate removal each package contains an pgkinfo/MANIFEST.pkgname file which list all the files belong to the package. M-x package-admin-delete-binary-package RET can be used to remove a package using this file.

Note that the interactive package tools included with XEmacs already do this for you.

Q2.1.5: Which packages to install?
----------------------------------

Unless you are an advanced user, just install everything.

If you really want to install only what's absolutely needed, a good minimal set of packages for XEmacs-latin1 would be

     xemacs-base, xemacs-devel, c-support, cc-mode, debug, dired, efs,
     edit-utils, fsf-compat, mail-lib, net-utils, os-utils, prog-modes,
     text-modes, time, mailcrypt

If you are using the XEmacs package tools, don't forget to do:

     	Packages -> Add Required

To make sure you have everything that the packages you have chosen to install need.

See Q1.7.2, for a description of the various packages.

Q2.1.6: Can you describe the package location process in more detail?
---------------------------------------------------------------------

On startup XEmacs looks for packages in so-called package hierarchies. Normally, there are three system wide hierarchies, like this:

     $prefix/lib/xemacs/xemacs-packages/
          Normal packages go here.

     $prefix/lib/xemacs/mule-packages/
          Mule packages go here and are only searched by MULE-enabled XEmacsen.

     $prefix/lib/xemacs/site-packages/
          Local and 3rd party packages go here.

This is what you get when you untar the SUMO tarballs under $prefix/lib/xemacs.

$prefix is specified using the --prefix parameter to configure, and defaults to usr/local.

If the package path is not explicitly specified, XEmacs looks for the package directory xemacs-packages (and mule-packages and site-packages) first under ~/.xemacs, then for a sister directory lib/xemacs-VERSION of the directory in which the XEmacs executable is located, then for a sister directory lib/xemacs.  The XEmacs executable (under Unix at least) is installed by default in /usr/local/bin; this explains why XEmacs in its default installation will find packages that you put under /usr/local/lib/xemacs.

You can specify where exactly XEmacs looks for packages by using the --with-package-prefix or --with-package-path parameters to configure (or the equivalent settings in config.inc, under Windows), or setting the EMACSPACKAGEPATH environment variable (which has the same format as --with-package-path).  See Q2.1.1.

See configure.usage for more info about the format of these configure parameters.

In addition to the system wide packages, each user can have his own packages installed under ~/.xemacs/. If you want to install packages there using the interactive tools, you need to set package-get-install-to-user-init-directory to t.

The site-packages hierarchy replaces the old site-lisp directory.  XEmacs no longer looks into a site-lisp directly by default.  A good place to put site-start.el would be in $prefix/lib/xemacs/site-packages/lisp/.

Q2.1.7: EFS fails with "500 AUTH not understood" (NEW)
------------------------------------------------------

A typical error: FTP Error: USER request failed; 500 AUTH not understood.

Thanks to giacomo boffi giacomo.boffi@polimi.it who recommends on comp.emacs.xemacs:

tell your ftp client to not attempt AUTH authentication (or do not use FTP servers that don't understand AUTH)

and notes that you need to add an element (often "-u") to `efs-ftp-program-args'.  Use M-x customize-variable, and verify the needed flag with `man ftp' or other local documentation.

2.2: Unix/Mac OS X Installation (Also Relevant to Cygwin, MinGW)
================================================================

Q2.2.1: Libraries in non-standard locations
-------------------------------------------

If your libraries are in a non-standard location, you can specify the location using the following flags to configure.  Under 21.4 or earlier:

     --site-libraries=WHATEVER
     --site-includes=WHATEVER

Under 21.5 or later:

     --with-site-libraries=WHATEVER
     --with-site-includes=WHATEVER

If you have multiple paths to specify, use the following syntax:

     --site-libraries='/path/one /path/two /path/etc'

If the libraries and headers reside in the directories lib and include of a common root (say /sw) then both can be specified with a single option:

     --site-prefixes=WHATEVER

or for 21.5:

     --with-site-prefixes=WHATEVER

Q2.2.2: Why can't I strip XEmacs?
---------------------------------

Richard Cognot writes:

     Because of the way XEmacs (and every other Emacsen, AFAIK) is built. The link gives you a bare-boned emacs (called temacs). temacs is then run, preloading some of the lisp files. The result is then dumped into a new executable, named xemacs, which will contain all of the preloaded lisp functions and data.

     Now, during the dump itself, the executable (code+data+symbols) is written on disk using a special unexec() function. This function is obviously heavily system dependent. And on some systems, it leads to an executable which, although valid, cannot be stripped without damage. If memory serves, this is especially the case for AIX binaries. On other architectures it might work OK.

     The Right Way to strip the emacs binary is to strip temacs prior to dumping xemacs. This will always work, although you can do that only if you install from sources (as temacs is not part of the binary kits).

Nat Makarevitch writes:

     Here is the trick:

      1. [ ./configure; make ]

      2. rm src/xemacs

      3. strip src/temacs

      4. make

      5. cp src/xemacs /usr/local/bin/xemacs

      6. cp lib-src/DOC-19.16-XEmacs /usr/local/lib/xemacs-19.16/i586-unknown-linuxaout

Q2.2.3: X11/bitmaps/gray (or other X11-related file) not found.
---------------------------------------------------------------

The X11R6 distribution was monolithic, but the X11R7 distribution is much more modular.  Many OS distributions omit these bitmaps (assuming nobody uses them, evidently).  Your OS distribution should have a developer's package containing these files, probably with a name containing the string "bitmap".  Known package names (you may need to add an extension such as .deb or .rpm) include x11/xbitmaps (Ubuntu) and xorg-x11-xbitmaps (Fedora Core 5).

2.3: Windows Installation (Windows, Cygwin, MinGW)
==================================================

Q2.3.1: What exactly are all the different ways to build XEmacs under Windows?
------------------------------------------------------------------------------

XEmacs can be built in several ways in the MS Windows environment.

The standard way is what we call the "native" port.  It uses the Win32 API and has no connection with X whatsoever -- it does not require X libraries to build, nor does it require an X server to run.  The native port is the most reliable version and provides the best graphical support.  Almost all development is geared towards this version, and there is little reason not to use it.

The second way to build is the Cygwin port.  It takes advantage of Cygnus emulation library under Win32.  See and do I need them to run XEmacs?, for more information.

A third way is the MinGW port.  It uses the Cygwin environment to build but does not require it at runtime.  See and do I need them to run XEmacs?, for more information.

Finally, you might also be able to build the non-Cygwin, non-MinGW "X" port.  This was actually the first version of XEmacs that ran under MS Windows, and although the code is still in XEmacs, it's essentially orphaned and it's unlikely it will compile without a lot of work.  If you want an MS Windows versin of XEmacs that supports X, use the Cygwin version. (The X support there is actively maintained, so that Windows developers can test the X support in XEmacs.)

Q2.3.2: What compiler/libraries do I need to compile XEmacs?
------------------------------------------------------------

You need Visual C++ 4.2, 5.0, or 6.0 for the native version. (We have some beta testers currently trying to compile with VC.NET, aka version 7.0, but we can't yet report complete success.) For the Cygwin and MinGW versions, you need the Cygwin environment, which comes with GCC, the compiler used for those versions.  See and do I need them to run XEmacs?, for more information on Cygwin and MinGW.

Q2.3.3: How do I compile the native port?
-----------------------------------------

Please read the file nt/README in the XEmacs distribution, which contains the full description.

Q2.3.4: What do I need for Cygwin?
----------------------------------

You can find the Cygwin tools and compiler at:

http://www.cygwin.com/

Click on the Install or update now! link, which will download a file setup.exe, which you can use to download everything else. (You will need to pick a mirror site; mirrors.rcn.net is probably the best.) You should go ahead and install everything -- you'll get various ancillary libraries that XEmacs needs or likes, e.g. XPM, PNG, JPEG, TIFF, etc.  You can also get X Windows here, if you want to compile under X.

If you want to compile without X, you will need the xpm-nox library, which must be specifically selected in the Cygwin netinstaller; it is not selected by default.  The package has had various names. Currently it is called cygXpm-noX4.dll.

Q2.3.5: How do I compile under Cygwin?
--------------------------------------

Similar as on Unix; use the usual `configure' and `make' process. Some problems to watch out for:

  * make sure HOME is set. This controls where you init.el file comes from;

  * CYGWIN needs to be set to tty for process support to work;

  * picking up some other grep or other UNIX-like tools can kill configure;

  * static heap too small, adjust src/sheap-adjust.h to a more positive number;

  * (Unconfirmed) The Cygwin version doesn't understand //machine/path type paths so you will need to manually mount a directory of this form under a unix style directory for a build to work on the directory;

  * If you're building WITHOUT X11, don't forget to change symlinks /usr/lib/libXpm.a and /usr/lib/libXpm.dll.a to point to the non-X versions of these libraries.  By default they point to the X versions.  So:

          /usr/lib/libXpm.a     -> /usr/lib/libXpm-noX.a
          /usr/lib/libXpm.dll.a -> /usr/lib/libXpm-noX.dll.a

     (This advice may now be obsolete because of the availability of the cygXpm-noX4.dll package from Cygwin.  Send confirmation to faq@xemacs.org.)

  * Other problems are listed in the PROBLEMS file, in the top-level directory of the XEmacs sources.

Q2.3.6: How do I compile using MinGW (aka the -mno-cygwin flag to gcc)?
-----------------------------------------------------------------------

Similar to the method for Unix.  Things to remember:

  * Specify the target host on the command line for ./configure, e.g. ./configure i586-pc-mingw32.

  * Be sure that your build directory is mounted such that it has the same path either as a cygwin path (/build/xemacs) or as a Windows path (c:\build\xemacs).

  * Build gcc -mno-cygwin versions of the extra libs, i.e. libpng, compface, etc.

  * Specify the target location of the extra libs on the command line to configure, e.g.for 21.4 or earlier ./configure --site-prefixes=/build/libs i586-pc-mingw32 and for 21.5 or later ./configure --with-site-prefixes=/build/libs i586-pc-mingw32.

Q2.3.7: How do I compile with X support?
----------------------------------------

To compile under Cygwin, all you need to do is install XFree86, which is available as part of the standard Cygwin installation. http://www.cygwin.com/.  Once installed, configure should automatically find the X libraries and compile with X support.

As noted above, the non-Cygwin X support is basically orphaned, and probably won't work.  But if it want to try, it's described in nt/README in some detail.  Basically, you need to get X11 libraries from http://ftp.x.org, and compile them.  If the precompiled versions are available somewhere, we don't know of it.

Q2.3.8: Cygwin XEmacs won't start -- cygXpm-noX4.dll was not found (NEW)
------------------------------------------------------------------------

The Cygwin binary distributed with the netinstaller uses an external DLL to handle XPM images (such as toolbar buttons).  You may get an error like

     This application has failed to start because cygXpm-noX4.dll was not found.
     Re-installing the application may fix this problem.

Andy Piper <andy@xemacs.org> sez:

     cygXpm-noX4 is part of the cygwin distribution under libraries or
     graphics, but is not installed by default. You need to run the
     cygwin setup again and select this package.

Ie, reinstalling XEmacs won't help because it is not part of the XEmacs distribution.

2.4: General Troubleshooting
============================

Q2.4.1: How do I deal with bugs or with problems building, installing, or running?
----------------------------------------------------------------------------------

The file PROBLEMS contains information on many common problems that occur in building, installing and running XEmacs.

Reports of bugs in XEmacs should be sent to xemacs-beta@xemacs.org.  You can also post to the newsgroup comp.emacs.xemacs (or equivalentlt, send to the mailing list xemacs@xemacs.org), but it is less likely that the developers will see it in a timely fashion.  See Bugs (the XEmacs User's Manual), for more information on how to report bugs. See Q1.4.2, for more information on mailing lists relating to XEmacs.

There are three ways to read the Bugs section.

 1. In a printed copy of the XEmacs manual.

 2. With Info.  First, start XEmacs.  From the menu, select Help->Info (Online Docs)->Info Contents to enter Info, then click on XEmacs, then on Bugs.  Or, use the keyboard: do C-h i to enter Info, then m XEmacs RET to get to the Emacs manual, then m Bugs RET to get to the section on bugs.  Or use standalone Info in a like manner.  (Standalone Info is part of the Texinfo distribution, not part of the XEmacs distribution.)

 3. By hand.  Do

          cat info/xemacs* | more "+/^File: xemacs.info,  Node: Bugs,"

Q2.4.2: Help! XEmacs just crashed on me!
----------------------------------------

First of all, don't panic.  Whenever XEmacs crashes, it tries extremely hard to auto-save all of your files before dying.  (The main time that this will not happen is if the machine physically lost power or if you killed the XEmacs process using kill -9).  The next time you try to edit those files, you will be informed that a more recent auto-save file exists.  You can use M-x recover-file to retrieve the auto-saved version of the file.

You can use the command M-x recover-session after a crash to pick up where you left off.

Now, XEmacs is not perfect, and there may occasionally be times, or particular sequences of actions, that cause it to crash.  If you can come up with a reproducible way of doing this (or even if you have a pretty good memory of exactly what you were doing at the time), the maintainers would be very interested in knowing about it.  The best way to report a bug is using M-x report-emacs-bug (or by selecting Send Bug Report... from the Help menu).  If that won't work (e.g. you can't get XEmacs working at all), send ordinary mail to xemacs-beta@xemacs.org. MAKE SURE to include the output from the crash, especially including the Lisp backtrace, as well as the XEmacs configuration from M-x describe-installation (or equivalently, the file Installation in the top of the build tree).  Note that the developers do not usually follow comp.emacs.xemacs on a regular basis; thus, this is better for general questions about XEmacs than bug reports.

If at all possible, include a C stack backtrace of the core dump that was produced.  This shows where exactly things went wrong, and makes it much easier to diagnose problems.  To do this under Unix and Mac OS X, you need to locate the core file (it's called core, and is usually sitting in the directory that you started XEmacs from, or your home directory if that other directory was not writable).  Then, go to that directory and execute a command like:

     gdb `which xemacs` core

and then issue the command where to get the stack backtrace.  You might have to use dbx or some similar debugger in place of gdb.  If you don't have any such debugger available, complain to your system administrator.

It's possible that a core file didn't get produced or the stack trace from gdb is garbage, in which case you're out of luck unless you can reproduce the bug.  A nonexistent core file can happen in some circumstances on some operating systems, depending on what exactly triggered the crash.  It's also possible, however, that your limits are set to turn them off.  You may be able to reenable them using a command like unlimit coredumpsize or ulimit -c. (To find out how your limits are set, use the command limit.) However, if you didn't explicitly set your limits this way, go complain to your system administrator and tell him not to disable core files by default.

A garbaged stack trace can happen for various reasons.  Some versions of gdb are broken on certain operating systems and aren't able to read the core file.  It's also possible that the stack got overwritten during the crash.  A very simple reason, however, is that your version of XEmacs was compiled without debugging information or had the debugging information stripped.  A compilation with optimization can also result in partly or completely garbaged stack trace.  In such cases, you will need to recompile XEmacs with debugging information and without optimization; see How to debug an XEmacs problem with a debugger.  Note also that core files currently don't work at all under Cygwin, and the only way to get a backtrace is to run XEmacs from gdb.

If you cannot get a backtrace from the core dump, but can reproduce the problem, try running XEmacs under gdb.  The goal is to get clean C and Lisp backtraces and submit a bug report including full configuration information as described above, as this will greatly assist in the process of tracking down the bug.  However, even partial information is better than none.  The process of getting backtraces from gdb is described in detail in How to debug an XEmacs problem with a debugger.

If you're under Microsoft Windows, you're out of luck unless you happen to have a debugging aid installed on your system, for example Visual C++.  In this case, the crash will result in a message giving you the option to enter a debugger (for example, by pressing Cancel).  Do this and locate the stack-trace window. (If your XEmacs was built without debugging information, the stack trace may not be very useful.)

When making a problem report make sure that:

 1. Report all of the information output by XEmacs during the crash.

 2. You mention what O/S and Hardware you are running XEmacs on.

 3. What version of XEmacs you are running.

 4. What build options you are using.

 5. If the problem is related to graphics and you are running Unix or Mac OS X, we will also need to know what version of the X Window System you are running, and what window manager you are using.

 6. If the problem happened on a TTY, please include the terminal type.

 7. Try very hard to get both C and Lisp backtraces, as described above.

Much of the information above is automatically generated by M-x report-emacs-bug.  Even more, and often useful, information can be generated by redirecting the output of make and make check to a file (beta.err is the default used by build-report), and executing M-x build-report.

Q2.4.3: XEmacs crashes and I compiled it myself.
------------------------------------------------

There have been a variety of reports of crashes due to compilers with buggy optimizers.  If you are compiling with optimization, consider turning it off (see How to debug an XEmacs problem with a debugger) and recompiling.

Please see the PROBLEMS file that comes with XEmacs (it's in the top-level source directory) to read what it says about your platform.

If you compiled XEmacs 21.4 or ealier using --use-union-type, or 21.5 or later using --enable-union-type (or in either case used the option USE_UNION_TYPE in config.inc under Windows), try recompiling again without it.  The union type has been known to trigger compiler errors in a number of cases.

Q2.4.4: How to debug an XEmacs problem with a debugger
------------------------------------------------------

If XEmacs does crash on you, one of the most productive things you can do to help get the bug fixed is to poke around a bit with the debugger. Here are some hints:

  * First of all, if the crash is at all reproducible, consider very strongly recompiling your XEmacs with debugging symbols and with no optimization (e.g. with GCC use the compiler flags -g -O0 -- that's an "oh" followed by a zero), and with the configure options --debug=yes and --error-checking=all (--enable-debug=yes and --enable-error-checking=all on XEmacs 21.5 or later).  This will make your XEmacs run somewhat slower, but you are a lot more likely to catch the problem earlier (closer to its source).  It makes it a lot easier to determine what's going on with a debugger.  The way to control the compiler flags is with the configuration option --cflags (--with-cflags in 21.5).  If you have a recent version of 21.5, you should use --without-optimization in preference to directly setting --cflags.

  * If it's not a true crash (i.e., XEmacs is hung, or a zombie process), or it's inconvenient to run XEmacs again because XEmacs is already running or is running in batch mode as part of a bunch of scripts, you may be able to attach to the existing process with your debugger.  Under Unix and Mac OS X, the typical way to do this is to first use some variant of the ps command to figure out the process ID of XEmacs, for example ps -auxww | grep xemacs under a BSD variant, ps -elf | grep xemacs under Linux or System V, or ps -aW | grep xemacs under Cygwin.  Then run

          gdb /path/to/xemacs/xemacs ####

     Where #### is the process id of your XEmacs. (If you're not sure, try using which xemacs.) When gdb attaches, the xemacs will stop and you can type where in gdb to get a stack trace as usual.  To get things moving again, you can just type quit in gdb.  It'll tell you the program is running and ask if you want to quit anyways.  Say y and it'll quit and have your emacs continue from where it was at.

     If you're running another debugger, a similar method may work, or you may have to run the debugger first and then use the attach command or something similar.

     Under Microsoft Windows, use the menu item Build->Start Debug->Attach to Process... and select the XEmacs process from the list given.

  * If you're able to run XEmacs under a debugger and reproduce the crash, here are some things you can do:

  * If XEmacs is hitting an assertion failure, put a breakpoint on assert_failed().

  * If XEmacs is hitting some weird Lisp error that's causing it to crash (e.g. during startup), put a breakpoint on signal_1()---this is declared static in eval.c.

  * If XEmacs is outputting lots of X errors, put a breakpoint on x_error_handler(); that will tell you which call is causing them.  Note that the result may not be very useful by default because X Windows normally operates asynchronously: A bunch of commands are buffered up and then sent to the server all at once.  This greatly improves performance over a network but means that an error may not be reported until the server receives the commands, which can be long after XEmacs made the erroneous calls.  For best results, you need to make the X server synchronous before getting the backtrace.  This can be done by starting XEmacs with the -sync option or executing the Lisp code (x-debug-mode t).

  * Internally, you will probably see lots of variables that hold objects of type Lisp_Object.  These are references to Lisp objects. Printing them out with the debugger probably won't be too useful---you'll likely just see a number.  To decode them, do this:

          call debug_print (OBJECT)

     where OBJECT is whatever you want to decode (it can be a variable, a function call, etc.).  This uses the Lisp printing routines to out a readable representation on the TTY from which the xemacs process was invoked.

     Under 21.5 and later, dp is defined as an easier-to-type equivalent of debug_print.  You can also try dpa if you can't see the output from debug_print (this will return a string containing the output), or use debug_p3 if debug_print itself triggers a crash (this is a less comprehensive but super-safe way to print out a Lisp object).

  * If you want to get a Lisp backtrace showing the Lisp call stack, do this:

          call debug_backtrace ()

     Under 21.5 and later, db is defined as an easier-to-type equivalent of debug_backtrace.

  * Using debug_print and debug_backtrace has two disadvantages - they can only be used with a running (including hung or zombie) xemacs process, and they do not display the internal C structure of a Lisp Object.  Even if all you've got is a core dump, all is not lost.

     If you're using GDB, there are some macros in the file src/.gdbinit in the XEmacs source distribution that should make it easier for you to decode Lisp objects.  This file is automatically read by gdb if gdb is run in the directory where xemacs was built, and contains these useful macros to inspect the state of xemacs:

     pobj
          Usage: pobj lisp_object

          Print the internal C representation of a lisp object.

     xtype
          Usage: xtype lisp_object

          Print the Lisp type of a lisp object.

     lbt
          Usage: lbt

          Print the current Lisp stack trace. Requires a running xemacs process.  (It works by calling the db routine described above.)

     ldp
          Usage: ldp lisp_object

          Print a Lisp Object value using the Lisp printer. Requires a running xemacs process.  (It works by calling the dp routine described above.)

     run-temacs
          Usage: run-temacs

          Run temacs interactively, like xemacs. Use this with debugging tools (like purify) that cannot deal with dumping, or when temacs builds successfully, but xemacs does not.

     dump-temacs
          Usage: dump-temacs

          Run the dumping part of the build procedure. Use when debugging temacs, not xemacs! Use this when temacs builds successfully, but xemacs does not.

     check-xemacs
          Usage: check-xemacs

          Run the test suite.  Equivalent to 'make check'.

     check-temacs
          Usage: check-temacs

          Run the test suite on temacs.  Equivalent to 'make check-temacs'. Use this with debugging tools (like purify) that cannot deal with dumping, or when temacs builds successfully, but xemacs does not.

     If you are using Sun's dbx debugger, there is an equivalent file src/.dbxrc, which defines the same commands for dbx.

  * If you're using a debugger to get a C stack backtrace and you're seeing stack traces with some of the innermost frames mangled, it may be due to dynamic linking. (This happens especially under Linux.) Consider reconfiguring with --dynamic=no (--with-dynamic=no in 21.5 or later).  Also, sometimes (again under Linux), stack backtraces of core dumps will have the frame where the fatal signal occurred mangled; if you can obtain a stack trace while running the XEmacs process under a debugger, the stack trace should be clean.

     Curtiss suggests upgrading to ld.so version 1.8 if dynamic linking and debugging is a problem on Linux.

  * If you're using a debugger to get a C stack backtrace and you're getting a completely mangled and bogus stack trace, it's probably due to one of the following:

      a. Your executable has been stripped.  Bad news.  Tell your sysadmin not to do this---it doesn't accomplish anything except to save a bit of disk space, and makes debugging much much harder.

      b. Your stack is getting trashed.  Debugging this is hard; you have to do a binary-search type of narrowing down where the crash occurs, until you figure out exactly which line is causing the problem.  Of course, this only works if the bug is highly reproducible.  Also, in many cases if you run XEmacs from the debugger, the debugger can protect the stack somewhat.  However, if the stack is being smashed, it is typically the case that there is a wild pointer somewhere in the program, often quite far from where the crash occurs.

      c. If your stack trace has exactly one frame in it, with address 0x0, this could simply mean that XEmacs attempted to execute code at that address, e.g. through jumping to a null function pointer.  Unfortunately, under those circumstances, GDB under Linux doesn't know how to get a stack trace. (Yes, this is the fourth Linux-related problem I've mentioned.  I have no idea why GDB under Linux is so bogus.  Complain to the GDB authors, or to comp.os.linux.development.system.) Again, you'll have to use the narrowing-down process described above.

      d. You will get a Lisp backtrace output when XEmacs crashes, so you'll have something useful.

  * If you compile with the newer gcc variants gcc-2.8 or egcs, you will also need gdb 4.17 or above.  Earlier releases of gdb can't handle the debug information generated by the newer compilers.

  * In versions of XEmacs before 21.2.27, src/.gdbinit was named src/gdbinit.  This had the disadvantage of not being sourced automatically by gdb, so you had to set that up yourself.

  * If you are running Microsoft Windows, the the file nt/README for further information about debugging XEmacs.

Q2.4.5: I get a cryptic error message when trying to do something.
------------------------------------------------------------------

When I try to use some particular option of some particular package, I get a cryptic error message in the minibuffer.

If the message went by too quickly, use Help->Recent Messages from the menubar (or type C-h l) to see recent messages.

If you can't figure out what's going on, select Options->Troubleshooting->Debug on Error from the menubar (or type M-: then (setq debug-on-error t)) then try and make the error happen again.  This will put in the debugger (you can get out of this and continue what you were doing before by typing c) and give you a backtrace that may be enlightening.  If not, try reading through this FAQ; if that fails, you could try posting to comp.emacs.xemacs (making sure to include the backtrace) and someone may be able to help.  If you can identify which XEmacs Lisp source file the error is coming from you can get a more detailed stack backtrace by doing the following:

 1. Visit the .el file in an XEmacs buffer.

 2. Issue the command M-x eval-current-buffer.

 3. Reproduce the error.

For more information on debugging Lisp code, see Debugging (XEmacs Lisp Reference Manual).

Q2.4.6: XEmacs hangs when I try to do something.
------------------------------------------------

XEmacs might just be slow; some operations take a long time.  XEmacs may also be waiting on a response from the network, for example when you are trying to send mail.

You can usually interrupt XEmacs by typing C-g.  If not (for example, Lisp code explicitly disabled this by setting inhibit-quit), you can use the "critical quit" mechanism by typing Control-Shift-G.  This should also pop you into the debugger and give you a backtrace, which can tell you where the problem is (see How to debug an XEmacs problem with a debugger). (Note that setting debug-on-quit or selecting Options->Troubleshooting->Debug on Quit will also cause regular C-g to enter the debugger and give you a backtrace.)

If you can't interrupt XEmacs this way, or for some reason XEmacs is not talking to the keyboard, you can try sending the SIGINT signal using the kill command.

If the Lisp backtrace isn't enlightening, or if XEmacs is so hung that you can't interrupt it at all, you could try attaching to the process and getting a C stack backtrace.  See How to debug an XEmacs problem with a debugger.

Q2.4.7: I get an error message when XEmacs is running in batch mode.
--------------------------------------------------------------------

Typically this happens when you are trying to compile some Elisp code. If you are doing this as part of XEmacs or the XEmacs packages, you should automatically get a backtrace, which can help you determine the source of the problem.  In other cases, you can get equivalent results by setting the environment variable XEMACSDEBUG to (setq stack-trace-on-error t load-always-display-messages t load-ignore-out-of-date-elc-files t load-show-full-path-in-messages t) (this needs to be all on one line; to set an environment variable, use export XEMACSDEBUG='FOO' under bash, zsh, etc. or setenv XEMACSDEBUG 'FOO' under csh and tcsh).  XEMACSDEBUG specifies Lisp code that will be executed at startup time.

If the backtrace is not sufficiently useful in helping you diagnose the problem, you should consider using a debugger such as GDB. See How to debug an XEmacs problem with a debugger.  You probably want to set a breakpoint on signal_1.  Since such errors often occur during compiling, which is often triggered by a complex command run from a make suite, it may be easier to attach to the process once it's running.

Under Microsoft Windows (and perhaps other operating systems), there is another useful trick you can do if you have configured with debugging support (configure option --debug (--with-debug in 21.5) or setting DEBUG_XEMACS in nt/config.inc).  Set the environment variable XEMACSDEBUG (as described above) to (setq debug-on-error t).  Then, when an error occurs noninteractively, instead of trying to invoke the Lisp debugger (which obviously won't work), XEmacs will break out to a C debugger using (force-debugging-signal t).  NOTE: This runs abort()!!! (As well as and after executing INT 3 under MS Windows, which should invoke a debugger if it's active.) This is guaranteed to kill XEmacs! (But in this situation, XEmacs is about to die anyway, and if no debugger is present, this will usefully dump core.)

Q2.4.8: The keyboard or mouse is not working properly, or I have some other event-related problem.
--------------------------------------------------------------------------------------------------

XEmacs has various facilities for debugging event handling.

First, try setting the variable debug-emacs-events to non-zero. This will output various information showing which events are being received and how they are being translated.  This may show you, for example, that a key command is getting intercepted using key-translation-map; this problem can otherwise be very tricky to debug.

Under X, you can see exactly which events are being received from the window system by setting x-debug-events to non-zero. (The value 1 gives you regular output, and 2 gives you verbose output, including all parameters.)

A similar facility exists under MS Windows: Set debug-mswindows-events to non-zero. (The value 1 gives you regular output.  The value 2 gives you verbose output, including all parameters.  The value 3 gives you super-gorily-detailed output.)

Q2.4.9: C-g doesn't work for me. Is it broken?
----------------------------------------------

C-g does work for most people in most circumstances.  If it doesn't, there are two possible explanations:

 1. XEmacs is hung in a way that prevents C-g from working.  This can happen when code is wrapped with a binding of inhibit-quit to t; you should still be able interrupt XEmacs using "critical quit".  On the other hand, XEmacs may be seriously wedged. (If you're lucky, sending SIGINT to the XEmacs process will interrupt it.) See XEmacs hangs when I try to do something..

 2. C-g is indeed broken on your system.  To test, try executing (while t) from the *scratch* buffer.  If C-g doesn't interrupt, then it's broken.  This used to happen with systems where SIGIO was broken, but BROKEN_SIGIO wasn't defined. However, there may not be very many such systems nowadays.

Q2.4.10: How do I debug process-related problems?
-------------------------------------------------

Under MS Windows, you can set the variable debug-mswindows-process-command-lines to non-nil to get information on exactly what is getting passed to a process.  This can be useful in determining problems with quoting. (Under Unix, a process receives each argument separately, but under MS Windows a single command line is received, and arguments with spaces or other special characters in them must be quoted.  Unfortunately this means that each process, potentially at least, has its own quoting conventions, and the code to process quoting conventions in cmd.exe, the Visual C++ startup code and the like is baroque and poorly documented. XEmacs uses the variable mswindows-construct-process-command-line-alist to construct a command line from a list of arguments based on the command to be run, but it is (and cannot be) a perfect solution.)

Q2.4.11: XEmacs is outputting lots of X errors.
-----------------------------------------------

If this is happening, we would very much like to know what's causing them.  To find this out, see How to debug an XEmacs problem with a debugger.  Try to get both a C and Lisp backtrace, and send them along with the full error output to xemacs-beta@xemacs.org.

Q2.4.12: After upgrading, XEmacs won't do `foo' any more!
---------------------------------------------------------

You have been used to doing `foo', but now when you invoke it (or click the toolbar button or select the menu item), nothing (or an error) happens.  The simplest explanation is that you are missing a package that is essential to you.  You can either track it down and install it (there is a list of packages and brief descriptions of their contents in etc/PACKAGES), or install the `Sumo Tarball' (see How do I figure out which packages to install?).

2.5: Startup-Related Problems
=============================

Q2.5.1: XEmacs cannot connect to my X Terminal!
-----------------------------------------------

Help!  I can not get XEmacs to display on my Envizex X-terminal!

Try setting the DISPLAY variable using the numeric IP address of the host you are running XEmacs from.

Q2.5.2 Startup problems related to paths or package locations.
--------------------------------------------------------------

First of all, if XEmacs can't find the packages, check to make sure that you put the packages in the right place, or that you told XEmacs where to look for the packages when you compiled it.  See Q2.1.1.

If something is still going wrong, or you get a startup warning about not being able to deduce some paths, you can get detailed information on the path-searching process at startup by setting the environment variable EMACSDEBUGPATHS to a non-null value.  One thing to look for if you're having package problems is the value of configure-package-path.  This corresponds to what was compiled into XEmacs using the --package-prefix or --package-path parameter (see Q2.1.1).  If this has the value of nil, this means that no value was compiled into XEmacs using these parameters.

Q2.5.3: XEmacs won't start without network.
-------------------------------------------

If XEmacs starts when you're on the network, but fails when you're not on the network, you may be missing a "localhost" entry in your /etc/hosts file.  The file should contain an entry like:

     127.0.0.1        localhost

Add that line, and XEmacs will be happy.

Q2.5.4: Startup warnings about deducing proper fonts?
-----------------------------------------------------

How can I avoid the startup warnings about deducing proper fonts?

This is highly dependent on your installation, but try with the following font as your base font for XEmacs and see what it does:

     -adobe-courier-medium-r-*-*-*-120-*-*-*-*-iso8859-1

More precisely, do the following in your resource file:

     Emacs.default.attributeFont: \
     -adobe-courier-medium-r-*-*-*-120-*-*-*-*-iso8859-1

If you just don't want to see the *Warnings* buffer at startup time, you can set this:

     (setq display-warning-minimum-level 'error)

The buffer still exists; it just isn't in your face.

Q2.5.5: Warnings from incorrect key modifiers.
----------------------------------------------

The following information comes from the PROBLEMS file that comes with XEmacs.

If you're having troubles with HP/UX it is because HP/UX defines the modifiers wrong in X.  Here is a shell script to fix the problem; be sure that it is run after VUE configures the X server.

     #! /bin/sh
     xmodmap 2> /dev/null - << EOF
     keysym Alt_L = Meta_L
     keysym Alt_R = Meta_R
     EOF

     xmodmap - << EOF
     clear mod1
     keysym Mode_switch = NoSymbol
     add mod1 = Meta_L
     keysym Meta_R = Mode_switch
     add mod2 = Mode_switch
     EOF

Q2.5.6: XEmacs 21.1 on Windows used to spawn an ugly console window on every startup. Has that been fixed?
----------------------------------------------------------------------------------------------------------

Yes.

The console was there because temacs (and in turn, xemacs) was a console application, and Windows typically creates a new console for a console process unless the creating process requests that one isn't created.  This used to be fixed with runemacs, a small Windows application that existed merely to start xemacs, stating that it didn't want a console.

XEmacs 21.4 fixes this cleanly by the virtue of being a true "GUI" application.  The explanation of what that means is included for educational value.

When building an application to be run in a Win32 environment, you must state which sub-system it is to run in.  Valid subsystems include "console" and "gui".  The subsystem you use affects the run time libraries linked into your application, the start up function that is run before control is handed over to your application, the entry point to your program, and how Windows normally invokes your program. (Console programs automatically get a console created for them at startup if their stdin/stdout don't point anywhere useful, which is the case when run from the GUI.  This is a stupid design, of course -- instead, the console should get created only when the first I/O actually occurs! GUI programs have an equally stupid design: When called from CMD.EXE/COMMAND.COM, their stdin/stdout will be set to point nowhere useful, even though the command shell has its own stdin/stdout.  It's as if someone who had learned a bit about stdio but had no actual knowledge of interprocess communication designed the scheme; unfortunately, the whole process-communication aspect of the Win32 API is equally badly designed.) For example, the entry point for a console app is "main" (which is what you'd expect for a C/C++ program), but the entry point for a "gui" app is "WinMain".  This confuses and annoys a lot of programmers who've grown up on Unix systems, where the kernel doesn't really care whether your application is a gui program or not.

For reasons not altogether clear, and are lost in the mists of time and tradition, XEmacs on Win32 started out as a console application, and therefore a console was automatically created for it. (It may have been made a console application partly because a console is needed in some circumstances, especially under Win95, to interrupt, terminate, or send signals to a child process, and because of the bogosity mentioned above with GUI programs and the standard command shell.  Currently, XEmacs just creates and immediately hides a console when necessary, and works around the "no useful stdio" problem by creating its own console window as necessary to display messages in.)

3 Editing Functions
*******************

This is part 3 of the XEmacs Frequently Asked Questions list.  This section is devoted to the editing-related capabilities of XEmacs (the keyboard, mouse, buffers, text selections, etc.) and how to customize them.

3.0: The Keyboard
=================

Q3.0.1: How can I customize the keyboard?
-----------------------------------------

#### Write me.

Q3.0.2: How can I bind complex functions (or macros) to keys?
-------------------------------------------------------------

As an example, say you want the paste key on a Sun keyboard to insert the current Primary X selection at point. You can accomplish this with:

     (define-key global-map [f18] 'x-insert-selection)

However, this only works if there is a current X selection (the selection will be highlighted).  The functionality I like is for the paste key to insert the current X selection if there is one, otherwise insert the contents of the clipboard.  To do this you need to pass arguments to x-insert-selection.  This is done by wrapping the call in a 'lambda form:

     (global-set-key [f18]
       (lambda () (interactive) (x-insert-selection t nil)))

This binds the f18 key to a generic functional object.  The interactive spec is required because only interactive functions can be bound to keys.

For the FAQ example you could use:

     (global-set-key [(control ?.)]
       (lambda () (interactive) (scroll-up 1)))
     (global-set-key [(control ?;)]
       (lambda () (interactive) (scroll-up -1)))

This is fine if you only need a few functions within the lambda body. If you're doing more it's cleaner to define a separate function. See How do I bind C-. and C-; to scroll one line up and down?.

Q3.0.3: How do I bind C-. and C-; to scroll one line up and down?
-----------------------------------------------------------------

Add the following (Thanks to Richard Mlynarik and Wayne Newberry) to .emacs:

     (defun scroll-up-one-line ()
       (interactive)
       (scroll-up 1))

     (defun scroll-down-one-line ()
       (interactive)
       (scroll-down 1))

     (global-set-key [(control ?.)] 'scroll-up-one-line) ; C-.
     (global-set-key [(control ?;)] 'scroll-down-one-line) ; C-;

The key point is that you can only bind simple functions to keys; you can not bind a key to a function that you're also passing arguments to.  (see How can I bind complex functions (or macros) to keys? for a better answer).

Q3.0.4: Globally binding Delete?
--------------------------------

I cannot manage to globally bind my Delete key to something other than the default.  How does one do this?

Answer: The problem is that many modes explicitly bind Delete.  To get around this, try the following:

     (defun foo ()
       (interactive)
       (message "You hit DELETE"))

     (define-key key-translation-map 'delete 'redirected-delete)
     (global-set-key 'redirected-delete 'foo)

Q3.0.5: How to map Help key alone on Sun type4 keyboard?
--------------------------------------------------------

The following works in GNU Emacs 19:

     (global-set-key [help] 'help-command);; Help

The following works in XEmacs with the addition of shift:

     (global-set-key [(shift help)] 'help-command);; Help

But it doesn't work alone.  This is in the file PROBLEMS which should have come with your XEmacs installation: Emacs ignores the help key when running OLWM.

OLWM grabs the help key, and retransmits it to the appropriate client using XSendEvent.  Allowing Emacs to react to synthetic events is a security hole, so this is turned off by default.  You can enable it by setting the variable x-allow-sendevents to t.  You can also cause fix this by telling OLWM to not grab the help key, with the null binding OpenWindows.KeyboardCommand.Help:.

Q3.0.6: How can you type in special characters in XEmacs?
---------------------------------------------------------

One way is to use the package x-compose.  Then you can use sequences like Compose " a to get ä, etc.

Another way is to use the iso-insert package. Then you can use sequences like C-x 8 " a to get ä, etc.

Glynn Clements writes:

     It depends upon your X server.

     Generally, the simplest way is to define a key as Multi_key with xmodmap, e.g.

                  xmodmap -e 'keycode 0xff20 = Multi_key'

     You will need to pick an appropriate keycode. Use xev to find out the keycodes for each key.

     [NB: On a `Windows' keyboard, recent versions of XFree86 automatically define the right `Windows' key as Multi_key'.]

     Once you have Multi_key defined, you can use e.g.

                  Multi a '       => á
                  Multi e "       => ë
                  Multi c ,       => ç

     etc.

     Also, recent versions of XFree86 define various AltGr-<key> combinations as dead keys, i.e.

                  AltGr [         => dead_diaeresis
                  AltGr ]         => dead_tilde
                  AltGr ;         => dead_acute

     etc.

     Running xmodmap -pk will list all of the defined keysyms.

For the related problem of displaying non-ASCII characters in a non-Mule XEmacs, see How do I display non-ASCII characters?.

Q3.0.7: Can I turn on sticky modifier keys?
-------------------------------------------

Yes, with (setq modifier-keys-are-sticky t).  This will give the effect of being able to press and release Shift and have the next character typed come out in upper case.  This will affect all the other modifier keys like Control and Meta as well.

Ben Wing writes:

     One thing about the sticky modifiers is that if you move the mouse out of the frame and back in, it cancels all currently ``stuck'' modifiers.

Q3.0.8: How do I map the arrow keys?
------------------------------------

Say you want to map C-right to forward-word:

Sam Steingold writes:

          ; both XEmacs and Emacs
          (define-key global-map [(control right)] 'forward-word)

     or

          ; Emacs only
          (define-key global-map [C-right] 'forward-word)

     or

          ; ver > 20, both
          (define-key global-map (kbd "C-<right>") 'forward-word)

Q3.0.9: HP Alt key as Meta.
---------------------------

How can I make XEmacs recognize the Alt key of my HP workstation as a Meta key?

Put the following line into a file and load it with xmodmap(1) before starting XEmacs:

     remove Mod1 = Mode_switch

Q3.0.10: Why does edt emulation not work?
-----------------------------------------

We don't know, but you can use tpu-edt emulation instead, which works fine and is a little fancier than the standard edt emulation.  To do this, add the following line to your init.el:

     (tpu-edt)

If you don't want it to replace C-h with an edt-style help menu add this as well:

     (global-set-key [(control h)] 'help-for-help)

Q3.0.11: How can I emulate VI and use it as my default mode?
------------------------------------------------------------

Our recommended VI emulator is viper. To make viper-mode the default, add this to your init.el:

     (viper-mode)

Michael Kifer writes:

     This should be added as close to the top of init.el as you can get it, otherwise some minor modes may not get viper-ized.

3.1: The Mouse
==============

Q3.1.1: How can I turn off Mouse pasting?
-----------------------------------------

I keep hitting the middle mouse button by accident and getting stuff pasted into my buffer so how can I turn this off?

Here is an alternative binding, whereby the middle mouse button selects (but does not cut) the expression under the mouse. Clicking middle on a left or right paren will select to the matching one.  Note that you can use define-key or global-set-key.

     (defun mouse-set-point-and-select (event)
       "Sets the point at the mouse location, then marks following form"
       (interactive "@e")
       (mouse-set-point event)
       (mark-sexp 1))
     (define-key global-map [button2] 'mouse-set-point-and-select)

Q3.1.2: How do I set control/meta/etc modifiers on mouse buttons?
-----------------------------------------------------------------

Use, for instance, [(meta button1)]. For example, here is a common setting for Common Lisp programmers who use the bundled ilisp package, whereby meta-button1 on a function name will find the file where the function name was defined, and put you at that location in the source file.

[Inside a function that gets called by the lisp-mode-hook and ilisp-mode-hook]

     (local-set-key [(meta button1)] 'edit-definitions-lisp)

Q3.1.3: Clicking the left button does not do anything in buffer list.
---------------------------------------------------------------------

I do C-x C-b to get a list of buffers and the entries get highlighted when I move the mouse over them but clicking the left mouse does not do anything.

Use the middle mouse button.

Q3.1.4: How can I get a list of buffers when I hit mouse button 3?
------------------------------------------------------------------

The following code will replace the default popup on button3:

     (global-set-key [button3] 'popup-buffer-menu)

Q3.1.5: How can I set XEmacs up so that it pastes where the text cursor is?
---------------------------------------------------------------------------

By default XEmacs pastes X selections where the mouse pointer is.  How do I disable this?

Examine the function mouse-yank, by typing C-h f mouse-yank RET.

To get XEmacs to paste at the text cursor, add this your init.el:

     (setq mouse-yank-at-point t)

You can also change this with Customize.  Select from the Options menu Advanced (Customize)->Emacs->Editing->Mouse->Yank At Point... or type M-x customize RET mouse RET.

3.2: Buffers, Text Editing
==========================

Q3.2.1: Can I have the end of the buffer delimited in some way?
---------------------------------------------------------------

Say, with: [END]?

Try this:

     (let ((ext (make-extent (point-min) (point-max))))
       (set-extent-property ext 'start-closed t)
       (set-extent-property ext 'end-closed t)
       (set-extent-property ext 'detachable nil)
       (set-extent-end-glyph ext (make-glyph [string :data "[END]"])))

Since this is XEmacs, you can specify an icon to be shown on window-system devices.  To do so, change the make-glyph call to something like this:

     (make-glyph '([xpm :file "~/something.xpm"]
                   [string :data "[END]"]))

You can inline the XPM definition yourself by specifying :data instead of :file.  Here is such a full-featured version that works on both X and TTY devices:

     (let ((ext (make-extent (point-min) (point-max))))
       (set-extent-property ext 'start-closed t)
       (set-extent-property ext 'end-closed t)
       (set-extent-property ext 'detachable nil)
       (set-extent-end-glyph ext (make-glyph '([xpm :data "\
     /* XPM */
     static char* eye = {
     \"20 11 7 2\",
     \"__ c None\"
     \"_` c #7f7f7f\",
     \"_a c #fefefe\",
     \"_b c #7f0000\",
     \"_c c #fefe00\",
     \"_d c #fe0000\",
     \"_e c #bfbfbf\",
     \"___________`_`_`___b_b_b_b_________`____\",
     \"_________`_`_`___b_c_c_c_b_b____________\",
     \"_____`_`_`_e___b_b_c_c_c___b___b_______`\",
     \"___`_`_e_a___b_b_d___b___b___b___b______\",
     \"_`_`_e_a_e___b_b_d_b___b___b___b___b____\",
     \"_`_`_a_e_a___b_b_d___b___b___b___b___b__\",
     \"_`_`_e_a_e___b_b_d_b___b___b___b___b_b__\",
     \"___`_`_e_a___b_b_b_d_c___b___b___d_b____\",
     \"_____`_`_e_e___b_b_b_d_c___b_b_d_b______\",
     \"_`_____`_`_`_`___b_b_b_d_d_d_d_b________\",
     \"___`_____`_`_`_`___b_b_b_b_b_b__________\",
     } ;"]
                                               [string :data "[END]"]))))

Note that you might want to make this a function, and put it to a hook. We leave that as an exercise for the reader.

Q3.2.2: How do I insert today's date into a buffer?
---------------------------------------------------

Like this:

     (insert (current-time-string))

Q3.2.3: How do I get a single minibuffer frame?
-----------------------------------------------

Vin Shelton writes:

     (setq initial-frame-plist '(minibuffer nil))
     (setq default-frame-plist '(minibuffer nil))
     (setq default-minibuffer-frame
           (make-frame
            '(minibuffer only
                         width 86
                         height 1
                         menubar-visible-p nil
                         default-toolbar-visible-p nil
                         name "minibuffer"
                         top -2
                         left -2
                         has-modeline-p nil)))
     (frame-notice-user-settings)

Please note: The single minibuffer frame may not be to everyone's taste, and there any number of other XEmacs options settings that may make it difficult or inconvenient to use.

Q3.2.4: How can I enable auto-indent and/or Filladapt?
------------------------------------------------------

Put the following line in your init.el:

     (setq indent-line-function 'indent-relative-maybe)

If you want to get fancy, try the filladapt package available standard with XEmacs.  Put this into your init.el:

     (require 'filladapt)
     (setq-default filladapt-mode t)
     (add-hook 'c-mode-hook 'turn-off-filladapt-mode)

This will enable Filladapt for all modes except C mode, where it doesn't work well.  To turn Filladapt on only in particular major modes, remove the (setq-default ...) line and use turn-on-filladapt-mode, like this:

     (add-hook 'text-mode-hook 'turn-on-filladapt-mode)

You can customize filling and adaptive filling with Customize. Select from the Options menu Advanced (Customize)->Emacs->Editing->Fill->Fill... or type M-x customize RET fill RET.

Note that well-behaving text-lookalike modes will run text-mode-hook by default (e.g. that's what Message does).  For the nasty ones, you'll have to provide the add-hooks yourself.

Please note that the fa-extras package is no longer useful.

Q3.2.5: How can I get XEmacs to come up in text/auto-fill mode by default?
--------------------------------------------------------------------------

Try the following lisp in your init.el:

     (setq default-major-mode 'text-mode)
     (add-hook 'text-mode-hook 'turn-on-auto-fill)

WARNING: note that changing the value of default-major-mode from fundamental-mode can break a large amount of built-in code that expects newly created buffers to be in fundamental-mode.  (Changing from fundamental-mode to text-mode might not wreak too much havoc, but changing to something more exotic like a lisp-mode would break many Emacs packages).

Note that Emacs by default starts up in buffer *scratch* in initial-major-mode, which defaults to lisp-interaction-mode. Thus adding the following form to your Emacs init file will cause the initial *scratch* buffer to be put into auto-fill'ed text-mode:

     (setq initial-major-mode
           (lambda ()
             (text-mode)
             (turn-on-auto-fill)))

Note that after your init file is loaded, if inhibit-startup-message is nil (the default) and the startup buffer is *scratch* then the startup message will be inserted into *scratch*; it will be removed after a timeout by erasing the entire *scratch* buffer.  Keep in mind this default usage of *scratch* if you desire any prior manipulation of *scratch* from within your Emacs init file. In particular, anything you insert into *scratch* from your init file will be later erased. Also, if you change the mode of the *scratch* buffer, be sure that this will not interfere with possible later insertion of the startup message (e.g. if you put *scratch* into a nonstandard mode that has automatic font lock rules, then the startup message might get fontified in a strange foreign manner, e.g. as code in some programming language).

3.3: Text Selections
====================

Q3.3.1: How do I select a rectangular region?
---------------------------------------------

Just select the region normally, then use the rectangle commands (e.g. kill-rectangle on it.  The region does not highlight as a rectangle, but the commands work just fine.

To actually sweep out rectangular regions with the mouse you can use mouse-track-do-rectangle which is assigned to M-button1. Then use rectangle commands.

You can also do the following to change default behavior to sweep out rectangular regions:

     (setq mouse-track-rectangle-p t)

You can also change this with Customize. Select from the Options menu Advanced (Customize)->Emacs->Editing->Mouse->Track Rectangle... or type M-x customize RET mouse RET.

      mouse-track-do-rectangle: (event)
        -- an interactive compiled Lisp function.
      Like `mouse-track' but selects rectangles instead of regions.

Q3.3.2: How can I turn off or change highlighted selections?
------------------------------------------------------------

The zmacs mode allows for what some might call gratuitous highlighting for selected regions (either by setting mark or by using the mouse).  This is the default behavior.  To turn off, add the following line to your init.el file:

     (setq zmacs-regions nil)

You can also change this with Customize.  Select from the Options menu Advanced (Customize)->Emacs->Editing->Basics->Zmacs Regions or type M-x customize RET editing-basics RET.

To change the face for selection, look at Options->Advanced (Customize) on the menubar.

Q3.3.3: How do I cause typing on an active region to remove it?
---------------------------------------------------------------

I want to change things so that if I select some text and start typing, the typed text replaces the selected text, similar to Motif.

You want to use something called pending delete.  Pending delete is what happens when you select a region (with the mouse or keyboard) and you press a key to replace the selected region by the key you typed. Usually backspace kills the selected region.

To get this behavior, ensure that you have the pc package installed, and add the following lines to your init.el:

     (cond
      ((fboundp 'turn-on-pending-delete)
       (turn-on-pending-delete))
      ((fboundp 'pending-delete-on)
       (pending-delete-on t)))

Note that this will work with both Backspace and Delete.  This code is a tad more complicated than it has to be for XEmacs in order to make it more portable.

Q3.3.4: Can I turn off the highlight during isearch?
----------------------------------------------------

I do not like my text highlighted while I am doing isearch as I am not able to see what's underneath.  How do I turn it off?

Put the following in your init.el:

     (setq isearch-highlight nil)

You can also change this with Customize. Type M-x customize-variable RET isearch-highlight RET.

Note also that isearch-highlight affects query-replace and ispell. Instead of disabling isearch-highlight you may find that a better solution consists of customizing the isearch face.

Q3.3.5: Why is killing so slow?
-------------------------------

This actually is an X Windows question, although you'll notice it with keyboard operations as well as while using the GUI.  Basically, there are four ways to communicate interprogram via the X server:

Primary selection
     a transient selection that gets replaced every time a new selection is made

Secondary selection
     for "exchanging" with the primary selection

Cut buffers
     a clipboard internal to the X server (deprecated)

Clipboard selection
     a selection with a notification protocol that allows a separate app to manage the clipboard

The cut buffers are deprecated because managing them is even more inefficient than the clipboard notification protocol.  The primary selection works fine for many users and applications, but is not very robust under intensive or sophisticated use.

In Motif and MS Windows, a clipboard has become the primary means for managing cut and paste.  These means that "modern" applications tend to be oriented toward a true clipboard, rather than the primary selection. (On Windows, there is nothing equivalent to the primary selection.) It's not that XEmacs doesn't support the simple primary selection method, it's that more and more other applications don't.

So the slowdown occurs because XEmacs now engages in the clipboard notification protocol on every kill.  This is especially slow on Motif.

With most people running most clients and server on the same host, and many of the rest working over very fast communication, you may expect that the situation is not going to improve.

There are a number of workarounds.  The most effective is to use a special command to do selection ownership only when you intend to paste to another application.  Useful commands are kill-primary-selection and copy-primary-selection.  These work only on text selected with the mouse (probably; experiment), and are bound by default to the Cut and Copy, respectively, buttons on the toolbar. copy-primary-selection is also bound to C-Insert.  You can yank the clipboard contents with yank-primary-selection, bound to the Paste toolbar button and Sh-Insert.

If you are communicating by cut and paste with applications that use the primary selection, then you can customize interprogram-cut-function to nil, restoring the XEmacs version 20 behavior.  How can you tell if a program will support this? Motifly-correct programs require the clipboard; you lose.  For others, only by trying it.  You also need to customize the complementary interprogram-paste-function to nil.  (Otherwise XEmacs-to-XEmacs pastes will not work correctly.)

You may get some relief on Motif by setting x-selection-strict-motif-ownership to nil, but this means you will only intermittently be able to paste XEmacs kills to Motif applications.

Thanks to Jeff Mincy and Glynn Clements for corrections.

Q3.3.6: Why does M-w take so long?
----------------------------------

It actually doesn't.  It leaves the region visible for a second so that you can see what area is being yanked.  If you start working, though, it will immediately complete its operation.  In other words, it will only delay for a second if you let it.

3.4: Editing Source Code
========================

Q3.4.1: I do not like cc-mode. How do I use the old c-mode?
-----------------------------------------------------------

Well, first off, consider if you really want to do this.  cc-mode is much more powerful than the old c-mode.  If you're having trouble getting your old offsets to work, try using c-set-offset instead. You might also consider using the package cc-compat.

But, if you still insist, add the following lines to your init.el:

     (fmakunbound 'c-mode)
     (makunbound 'c-mode-map)
     (fmakunbound 'c++-mode)
     (makunbound 'c++-mode-map)
     (makunbound 'c-style-alist)
     (load-library "old-c-mode")
     (load-library "old-c++-mode")

This must be done before any other reference is made to either c-mode or c++-mode.

Q3.4.2: How do you make XEmacs indent CL if-clauses correctly?
--------------------------------------------------------------

I'd like XEmacs to indent all the clauses of a Common Lisp if the same amount instead of indenting the 3rd clause differently from the first two.

The package cl-indent that comes with XEmacs sets up this kind of indentation by default.  cl-indent also knows about many other CL-specific forms.  To use cl-indent, one can do this:

     (setq lisp-indent-function 'common-lisp-indent-function)

One can also customize cl-indent.el so it mimics the default if indentation then indented more than the else. Here's how:

     (put 'if 'common-lisp-indent-function '(nil nil &body))

4 Display Functions
*******************

This is part 4 of the XEmacs Frequently Asked Questions list.  This section is devoted to the display-related capabilities of XEmacs (fonts, colors, modeline, menubar, toolbar, scrollbar, etc.) and how to customize them.

4.0: Textual Fonts and Colors
=============================

Q4.0.1: How do I specify a font?
--------------------------------

#### Update me.

In 21.4 and above, you can use the Options menu to change the font. You can also do it in your init file, e.g. like this (for MS Windows):

         (set-face-font 'default "Lucida Console:Regular:10")
         (set-face-font 'modeline "MS Sans Serif:Regular:10")

Q4.0.2: How do I set the text, menu and modeline fonts?
-------------------------------------------------------

#### Update me.

Note that you should use Emacs. and not Emacs* when setting face values.

In .Xresources:

     Emacs.default.attributeFont:  -*-*-medium-r-*-*-*-120-*-*-m-*-*-*
     Emacs*menubar*font:           fixed
     Emacs.modeline.attributeFont: fixed

This is confusing because default and modeline are face names, and can be found listed with all faces in the current mode by using M-x set-face-font (enter) ?.  They use the face-specific resource attributeFont.

On the other hand, menubar is a normal X thing that uses the resource font.  With Motif it may be necessary to use fontList instead of font.  In non-Motif configurations with Mule it is necessary to use fontSet instead of font.  (Sorry, there just is no simple recipe here.)

Q4.0.3: How can I set color options from init.el?
-------------------------------------------------

How can I set the most commonly used color options from my init.el instead of from my .Xresources?

Like this:

     (set-face-background 'default      "bisque") ; frame background
     (set-face-foreground 'default      "black") ; normal text
     (set-face-background 'zmacs-region "red") ; When selecting w/
                                             ; mouse
     (set-face-foreground 'zmacs-region "yellow")
     (set-face-font       'default      "*courier-bold-r*120-100-100*")
     (set-face-background 'highlight    "blue") ; Ie when selecting
                                             ; buffers
     (set-face-foreground 'highlight    "yellow")
     (set-face-background 'modeline     "blue") ; Line at bottom
                                             ; of buffer
     (set-face-foreground 'modeline     "white")
     (set-face-font       'modeline     "*bold-r-normal*140-100-100*")
     (set-face-background 'isearch      "yellow") ; When highlighting
                                             ; while searching
     (set-face-foreground 'isearch      "red")
     (setq x-pointer-foreground-color   "black") ; Adds to bg color,
                                             ; so keep black
     (setq x-pointer-background-color   "blue") ; This is color
                                             ; you really
                                             ; want ptr/crsr

Q4.0.4: How can I set the colors when highlighting a region?
------------------------------------------------------------

How can I set the background/foreground colors when highlighting a region?

You can change the face zmacs-region either in your .Xresources:

     Emacs.zmacs-region.attributeForeground: firebrick
     Emacs.zmacs-region.attributeBackground: lightseagreen

or in your init.el:

     (set-face-background 'zmacs-region "red")
     (set-face-foreground 'zmacs-region "yellow")

Q4.0.5: How can I limit color map usage?
----------------------------------------

I'm using Netscape (or another color grabber like XEmacs); is there any way to limit the number of available colors in the color map?

Answer: No, but you can start Netscape before XEmacs, and it will use the closest available color if the colormap is full.  You can also limit the number of colors Netscape uses, using the flags -mono, -ncols <#> or -install (for mono, limiting to <#> colors, or for using a private color map).

If you have the money, another solution would be to use a truecolor or direct color video.

Q4.0.6: My tty supports color, but XEmacs doesn't use them.
-----------------------------------------------------------

XEmacs tries to automatically determine whether your tty supports color, but sometimes guesses wrong.  In that case, you can make XEmacs Do The Right Thing using this Lisp code:

     (if (eq 'tty (device-type))
         (set-device-class nil 'color))

Q4.0.7: Can I have pixmap backgrounds in XEmacs?
------------------------------------------------

Juan Villacis writes:

     There are several ways to do it.  For example, you could specify a default pixmap image to use in your ~/.Xresources, e.g.,

            Emacs*EmacsFrame.default.attributeBackgroundPixmap: /path/to/image.xpm

     and then reload ~/.Xresources and restart XEmacs.  Alternatively, since each face can have its own pixmap background, a better way would be to set a face's pixmap within your XEmacs init file, e.g.,

            (set-face-background-pixmap 'default "/path/to/image.xpm")
            (set-face-background-pixmap 'bold    "/path/to/another_image.xpm")

     and so on.  You can also do this interactively via M-x edit-faces.

Q4.0.8: How do I display non-ASCII characters?
----------------------------------------------

If you're using a Mule-enabled XEmacs, then display is automatic.  If you're not seeing the characters you expect, either (1) you don't have appropriate fonts available or (2) XEmacs did not correctly detect the coding system (see Recognize Coding (xemacs)).  In case (1), install fonts as is customary for your platform.  In case (2), you need to tell XEmacs explicitly what coding systems you're using. Specify Coding (xemacs).

If your XEmacs is not Mule-enabled, and for some reason getting a Mule-enabled XEmacs seems like the wrong thing to do, all is not lost. You can arrange it by brute force.  In event-Xt.c (suppress the urge to look in this file---play Doom instead, because you'll survive longer), it is written:

     In a non-Mule world, a user can still have a multi-lingual editor, by doing (set-face-font "-*-iso8859-2" (current-buffer)) for all their Latin-2 buffers, etc.

For the related problem of inputting non-ASCII characters in a non-Mule XEmacs, see How can you type in special characters in XEmacs?.

Q4.0.9: Font selections in don't get saved after Save Options.
--------------------------------------------------------------

John Mann writes:

     You have to go to Options->Menubars and unselect Frame-Local Font Menu.  If this option is selected, font changes are only applied to the current frame and do not get saved when you save options.

Also, set the following in your init.el:

     (setq options-save-faces t)

4.1: Syntax Highlighting (Font Lock)
====================================

Q4.1.1: How can I do source code highlighting using font-lock?
--------------------------------------------------------------

For most modes, font-lock is already set up and just needs to be turned on.  This can be done by adding the line:

     (require 'font-lock)

to your init.el. (You can turn it on for the current buffer and session only by M-x font-lock-mode.) See the file etc/sample.init.el (etc/sample.emacs in XEmacs versions prior to 21.4) for more information.

See also Syntax Highlighting from the Options menu. Remember to save options.

Q4.1.2: How do I get More Syntax Highlighting on by default?
------------------------------------------------------------

Use the following code in your init.el:

     (setq-default font-lock-maximum-decoration t)

See also Syntax Highlighting from the Options menu. Remember to save options.

4.2: The Modeline
=================

Q4.2.1: How can I make the modeline go away?
--------------------------------------------

     (set-specifier has-modeline-p nil)

Q4.2.2: How do you have XEmacs display the line number in the modeline?
-----------------------------------------------------------------------

Add the following line to your init.el file to display the line number:

     (line-number-mode 1)

Use the following to display the column number:

     (column-number-mode 1)

Or select from the Options menu Advanced (Customize)->Emacs->Editing->Basics->Line Number Mode and/or Advanced (Customize)->Emacs->Editing->Basics->Column Number Mode

Or type M-x customize RET editing-basics RET.

Q4.2.3: How do I get XEmacs to put the time of day on the modeline?
-------------------------------------------------------------------

Add the following line to your init.el file to display the time:

     (display-time)

See Customize from the Options menu for customization.

Q4.2.4: How can I change the modeline color based on the mode used?
-------------------------------------------------------------------

You can use something like the following:

     (add-hook 'lisp-mode-hook
               (lambda ()
                 (set-face-background 'modeline "red" (current-buffer))))

Then, when editing a Lisp file (i.e. when in Lisp mode), the modeline colors change from the default set in your init.el. The change will only be made in the buffer you just entered (which contains the Lisp file you are editing) and will not affect the modeline colors anywhere else.

Notes:

  * The hook is the mode name plus -hook.  eg. c-mode-hook, c++-mode-hook, emacs-lisp-mode-hook (used for your init.el or a xx.el file), lisp-interaction-mode-hook (the *scratch* buffer), text-mode-hook, etc.

  * Be sure to use add-hook, not (setq c-mode-hook xxxx), otherwise you will erase anything that anybody has already put on the hook.

  * You can also do (set-face-font 'modeline FONT), eg. (set-face-font 'modeline "*bold-r-normal*140-100-100*" (current-buffer)) if you wish the modeline font to vary based on the current mode.

There are additional modeline faces, modeline-buffer-id, modeline-mousable, and modeline-mousable-minor-mode, which you may want to customize.

4.3: The Cursor
===============

Q4.3.1: Is there a way to make the bar cursor thicker?
------------------------------------------------------

I'd like to have the bar cursor a little thicker, as I tend to "lose" it often.

For a 1 pixel bar cursor, use:

     (setq bar-cursor t)

For a 2 pixel bar cursor, use:

     (setq bar-cursor 'anything-else)

You can also change these with Customize. Select from the Options menu Advanced (Customize)->Emacs->Environment->Display->Bar Cursor... or type M-x customize RET display RET.

You can use a color to make it stand out better:

     Emacs*cursorColor:      Red

Q4.3.2: Is there a way to get back the block cursor?
----------------------------------------------------

     (setq bar-cursor nil)

You can also change this with Customize. Select from the Options menu Advanced (Customize)->Emacs->Environment->Display->Bar Cursor... or type M-x customize RET display RET.

Q4.3.3: Can I make the cursor blink?
------------------------------------

Yes, like this:

     (blink-cursor-mode)

This function toggles between a steady cursor and a blinking cursor. You may also set this mode from the menu bar by selecting Options->Display->Blinking Cursor.  Remember to save options.

4.4: The Menubar
================

Q4.4.1: How do I get rid of the menubar?
----------------------------------------

     (set-specifier menubar-visible-p nil)

Q4.4.2: How can I customize the menubar?
----------------------------------------

For an extensive menubar, add this line to your init.el:

     (load "big-menubar")

If you'd like to write your own, this file provides as good a set of examples as any to start from.  The file is located in edit-utils package.

Q4.4.3: How do I enable use of the keyboard (Alt) to access menu items?
-----------------------------------------------------------------------

#### Write me.

Q4.4.4: How do I control how many buffers are listed in the menu Buffers List?
------------------------------------------------------------------------------

Add the following to your init.el (suit to fit):

     (setq buffers-menu-max-size 20)

For no limit, use an argument of nil.

You can also change this with Customize.  Select from the Options menu Advanced (Customize)->Emacs->Environment->Menu->Buffers Menu->Max Size... or type M-x customize RET buffers-menu RET.

Q4.4.5: Resources like Emacs*menubar*font are not working?
----------------------------------------------------------

I am trying to use a resource like Emacs*menubar*font to set the font of the menubar but it's not working.

In Motif, the use of font resources is obsoleted in order to support internationalization.  If you are using the real Motif menubar, this resource is not recognized at all; you have to say:

     Emacs*menubar*fontList: FONT

If you are using the Lucid menubar, for backward compatibility with existing user configurations, the font resource is recognized. Since this is not supported by Motif itself, the code is a kludge and the font resource will be recognized only if the fontList resource resource is unset.  This means that the resource

     *fontList: FONT

will override

     Emacs*menubar*font: FONT

even though the latter is more specific.

In non-Motif configurations using --with-mule and --with-xfs it is necessary to use the fontSet resource instead of the font resource.  The backward compatibility kludge was never implemented for non-Motif builds. Example:

     *fontSet: FONT

4.5: The Toolbar
================

Q4.5.1: How do I get rid of the toolbar?
----------------------------------------

#### Write me.

Q4.5.2: How can I customize the toolbar?
----------------------------------------

#### Write me.

Q4.5.3: How can I bind a key to a function to toggle the toolbar?
-----------------------------------------------------------------

Try something like:

     (defun my-toggle-toolbar ()
       (interactive)
       (set-specifier default-toolbar-visible-p
                      (not (specifier-instance default-toolbar-visible-p))))
     (global-set-key "\C-xT" 'my-toggle-toolbar)

Thanks to Martin Buchholz for the correct code.

Q4.5.4: Can't instantiate image error... in toolbar
---------------------------------------------------

Dr. Ram Samudrala writes:

I just installed the XEmacs (20.4-2) RPMS that I downloaded from http://www.xemacs.org/.  Everything works fine, except that when I place my mouse over the toolbar, it beeps and gives me this message:

      Can't instantiate image (probably cached):
      [xbm :mask-file "/usr/include/X11/bitmaps/leftptrmsk :mask-data
      (16 16 <strange control characters> ...

Kyle Jones writes:

     This is problem specific to some Chips and Technologies video chips, when running XFree86.  Putting

     Option "sw_cursor"

     in XF86Config gets rid of the problem.

4.6: Scrollbars and Scrolling
=============================

Q4.6.1: How can I disable the scrollbar?
----------------------------------------

To disable them for all frames, add the following line to your .Xresources:

     Emacs.scrollBarWidth:  0

Or select Options->Display->Scrollbars. Remember to save options.

To turn the scrollbar off on a per-frame basis, use the following function:

     (set-specifier scrollbar-width 0 (selected-frame))

You can actually turn the scrollbars on at any level you want by substituting for (selected-frame) in the above command.  For example, to turn the scrollbars off only in a single buffer:

     (set-specifier scrollbar-width 0 (current-buffer))

Q4.6.2: How can I change the scrollbar width?
---------------------------------------------

#### Write me.

Q4.6.3: How can I use resources to change scrollbar colors?
-----------------------------------------------------------

Here's a recap of how to use resources to change your scrollbar colors:

     ! Motif scrollbars

     Emacs*XmScrollBar.Background: skyblue
     Emacs*XmScrollBar.troughColor: lightgray

     ! Athena scrollbars

     Emacs*Scrollbar.Foreground: skyblue
     Emacs*Scrollbar.Background: lightgray

Note the capitalization of Scrollbar for the Athena widget.

Q4.6.4: Moving the scrollbar can move the point; can I disable this?
--------------------------------------------------------------------

When I move the scrollbar in an XEmacs window, it moves the point as well, which should not be the default behavior.  Is this a bug or a feature?  Can I disable it?

The current behavior is a feature, not a bug.  Point remains at the same buffer position as long as that position does not scroll off the screen. In that event, point will end up in either the upper-left or lower-left hand corner.

This cannot be changed.

Q4.6.5: Scrolling one line at a time.
-------------------------------------

Can the cursor keys scroll the screen a line at a time, rather than the default half page jump?  I tend it to find it disorienting.

Use the following:

     (setq scroll-step 1)

You can also change this with Customize.  Select from the Options menu Advanced (Customize)->Emacs->Environment->Windows->Scroll Step... or type M-x customize RET windows RET.

Q4.6.6: How can I turn off automatic horizontal scrolling in specific modes?
----------------------------------------------------------------------------

Do (setq truncate-lines t) in the mode-hooks for any modes in which you want lines truncated.

More precisely: If truncate-lines is nil, horizontal scrollbars will never appear.  Otherwise, they will appear only if the value of scrollbar-height for that buffer/window/etc. is non-zero.  If you do

     (set-specifier scrollbar-height 0)

then horizontal scrollbars will not appear in truncated buffers unless the package specifically asked for them.

Q4.6.7: I find auto-show-mode disconcerting. How do I turn it off?
------------------------------------------------------------------

auto-show-mode controls whether or not a horizontal scrollbar magically appears when a line is too long to be displayed.  This is enabled by default.  To turn it off, put the following in your init.el:

     (setq auto-show-mode nil)
     (setq-default auto-show-mode nil)

4.7: The Gutter Tabs, The Progress Bar, Widgets
===============================================

Q4.7.1: How can I disable the gutter tabs?
------------------------------------------

#### Write me.

Q4.7.2: How can I disable the progress bar?
-------------------------------------------

#### Write me.

Q4.7.3: There are bugs in the gutter or widgets.
------------------------------------------------

#### Write me.

Q4.7.4: How can I customize the gutter or gutter tabs?
------------------------------------------------------

#### Write me.

5 Interfacing with the Operating System and External Devices
************************************************************

This is part 5 of the XEmacs Frequently Asked Questions list.  This section is devoted to the various ways that XEmacs interfaces with the operating system, with other processes and with external devices such as speakers and the printer.

5.0: X Window System and Resources
==================================

Q5.0.1: Where is a list of X resources?
---------------------------------------

Search through the NEWS file for X Resources.  A fairly comprehensive list is given after it.

In addition, an app-defaults file etc/Emacs.ad is supplied, listing the defaults.  The file etc/sample.Xresources gives a different set of defaults that you might consider for installation in your ~/.Xresources file.  It is nearly the same as etc/Emacs.ad, but a few entries are altered.  Be careful about installing the contents of this file into your .Xresources (or legacy .Xdefaults) file if you use GNU Emacs under X11 as well.

Q5.0.2: How can I detect a color display?
-----------------------------------------

You can test the return value of the function (device-class), as in:

     (when (eq (device-class) 'color)
       (set-face-foreground  'font-lock-comment-face "Grey")
       (set-face-foreground  'font-lock-string-face  "Red")
       ....
       )

Q5.0.3: How can I get the icon to just say XEmacs?
--------------------------------------------------

I'd like the icon to just say XEmacs, and not include the name of the current file in it.

Add the following line to your init.el:

     (setq frame-icon-title-format "XEmacs")

Q5.0.4: How can I have the window title area display the full path?
-------------------------------------------------------------------

I'd like to have the window title area display the full directory/name of the current buffer file and not just the name.

Add the following line to your init.el:

     (setq frame-title-format "%S: %f")

A more sophisticated title might be:

     (setq frame-title-format
           '("%S: " (buffer-file-name "%f"
                                      (dired-directory dired-directory "%b"))))

That is, use the file name, or the dired-directory, or the buffer name.

Q5.0.5: xemacs -name junk doesn't work?
---------------------------------------

When I run xterm -name junk, I get an xterm whose class name according to xprop, is junk.  This is the way it's supposed to work, I think.  When I run xemacs -name junk the class name is not set to junk.  It's still emacs.  What does xemacs -name really do?  The reason I ask is that my window manager (fvwm) will make a window sticky and I use XEmacs to read my mail.  I want that XEmacs window to be sticky, without having to use the window manager's function to set the window sticky.  What gives?

xemacs -name sets the application name for the program (that is, the thing which normally comes from argv[0]).  Using -name is the same as making a copy of the executable with that new name.  The WM_CLASS property on each frame is set to the frame-name, and the application-class.  So, if you did xemacs -name FOO and then created a frame named BAR, you'd get an X window with WM_CLASS = ( "BAR", "Emacs").  However, the resource hierarchy for this widget would be:

     Name:    FOO   .shell             .container   .BAR
     Class:   Emacs .TopLevelEmacsShell.EmacsManager.EmacsFrame

instead of the default

     Name:    xemacs.shell             .container   .emacs
     Class:   Emacs .TopLevelEmacsShell.EmacsManager.EmacsFrame

It is arguable that the first element of WM_CLASS should be set to the application-name instead of the frame-name, but I think that's less flexible, since it does not give you the ability to have multiple frames with different WM_CLASS properties.  Another possibility would be for the default frame name to come from the application name instead of simply being emacs.  However, at this point, making that change would be troublesome: it would mean that many users would have to make yet another change to their resource files (since the default frame name would suddenly change from emacs to xemacs, or whatever the executable happened to be named), so we'd rather avoid it.

To make a frame with a particular name use:

     (make-frame '((name . "the-name")))

Q5.0.6: -iconic doesn't work.
-----------------------------

When I start up XEmacs using -iconic it doesn't work right. Using -unmapped on the command line, and setting the initiallyUnmapped X Resource don't seem to help much either...

Ben Wing writes:

     Ugh, this stuff is such an incredible mess that I've about given up getting it to work.  The principal problem is numerous window-manager bugs...

5.1: Microsoft Windows
======================

Q5.1.1: Does XEmacs rename all the win32-* symbols to w32-*?
------------------------------------------------------------

In his flavor of Emacs 20, Richard Stallman has renamed all the win32-* symbols to w32-*.  Does XEmacs do the same?

We consider such a move counter-productive, thus we do not use the w32 prefix. (His rather questionable justification was that he did not consider Windows to be a "winning" platform.) However, the name Win32 is not particularly descriptive outside the Windows world, and using just windows- would be too generic.  So we chose a compromise, the prefix mswindows- for Windows-related variables and functions.

Thus all the XEmacs variables and functions directly related to either the Windows GUI or OS are prefixed mswindows- (except for a couple of debugging variables, prefixed debug-mswindows-).  From an architectural perspective, however, we believe that this is mostly a non-issue because there should be a very small number of window-systems-specific variables anyway.  Whenever possible, we try to provide generic interfaces that apply to all window systems.

Q5.1.2: How do I get Windows Explorer to associate a file type with XEmacs?
---------------------------------------------------------------------------

Associating a new file type with XEmacs.
........................................

In Explorer select View->Options->File Types, press [New Type...] and fill in the dialog box, e.g.:

             Description of type:    Emacs Lisp source
             Associated extension:   el
             Content Type (MIME):    text/plain

then press [New...] and fill in the Action dialog box as follows:

             Action:
             Open

             Application used to perform action:
             D:\Full\path\for\xemacs.exe "%1"

             [x] Use DDE

             DDE Message:
             open("%1")

             Application:
             <leave blank>

             DDE Application Not Running:
             <leave blank>

             Topic:
             <leave blank>

Associating an existing file type with XEmacs.
..............................................

In Explorer select View->Options->File Types.  Click on the file type in the list and press [Edit...].  If the file type already has an Open action, double click on it and fill in the Action dialog box as described above; otherwise create a new action.

If the file type has more than one action listed, you probably want to make the Open action that you just edited the default by clicking on it and pressing Set Default.

Note for Windows 2000 users: Under Windows 2000, get to File Types using Control Panel->Folder Options->File Types.

5.2: Printing
=============

Q5.2.1: What do I need to change to make printing work?
-------------------------------------------------------

For regular printing there are two variables that can be customized.

lpr-command
     This should be set to a command that takes standard input and sends it to a printer.  Something like:

          (setq lpr-command "lp")

lpr-switches
     This should be set to a list that contains whatever the print command requires to do its job.  Something like:

          (setq lpr-switches '("-depson"))

For postscript printing there are three analogous variables to customize.

ps-lpr-command
     This should be set to a command that takes postscript on standard input and directs it to a postscript printer.

ps-lpr-switches
     This should be set to a list of switches required for ps-lpr-command to do its job.

ps-print-color-p
     This boolean variable should be set t if printing will be done in color, otherwise it should be set to nil.

NOTE: It is an undocumented limitation in XEmacs that postscript printing (the Pretty Print Buffer menu item) requires a window system environment.  It cannot be used outside of X11.

Q5.2.2: How can I print WYSIWYG a font-locked buffer?
-----------------------------------------------------

Font-lock looks nice.  How can I print (WYSIWYG) the highlighted document?

The package ps-print, which is now included with XEmacs, provides the ability to do this.  The source code contains complete instructions on its use, in $prefix/lib/xemacs/xemacs-packages/lisp/ps-print/ps-print.el, being the default location of an installed ps-print package.

Q5.2.3: Getting M-x lpr to work with postscript printer.
--------------------------------------------------------

My printer is a Postscript printer and lpr only works for Postscript files, so how do I get M-x lpr-region and M-x lpr-buffer to work?

Put something like this in your init.el:

     (setq lpr-command "a2ps")
     (setq lpr-switches '("-p" "-1"))

If you don't use a2ps to convert ASCII to postscript (why not, it's free?), replace with the command you do use.  Note also that some versions of a2ps require a -Pprinter to ensure spooling.

Q5.2.4: Can you print under MS Windows?
---------------------------------------

As of 21.4, printing works on Windows, using simply File->Print BUFFER..., and can be configured with File->Page Setup....

Prior to 21.4, there is no built-in support, but there are some clever hacks out there.  If you know how, please let us know and we'll put it here.

5.3: Sound
==========

Q5.3.1: How do I turn off the sound?
------------------------------------

Add the following line to your init.el:

     (setq bell-volume 0)
     (setq sound-alist nil)

That will make your XEmacs totally silent---even the default ding sound (TTY beep on TTY-s) will be gone.

You can also change these with Customize.  Select from the Options menu Advanced (Customize)->Emacs->Environment->Sound->Sound... or type M-x customize RET sound RET.

Q5.3.2: How do I get funky sounds instead of a boring beep?
-----------------------------------------------------------

Make sure your XEmacs was compiled with sound support, and then put this in your init.el:

     (load-default-sounds)

Q5.3.3: What are NAS and ESD (EsounD)?
--------------------------------------

Network Audio System (NAS) is a client-server sound library for X.

http://radscan.com/nas.html.

To build XEmacs with it, use the configure flag --with-sound=nas (--enable-sound=nas in 21.5 or later).

Enlightened Sound Daemon (ESD or EsounD) is yet another sound system.

http://www.tux.org/~ricdude/EsounD.html.

To build XEmacs with it, use the configure flag --with-sound=esd (--enable-sound=esd in 21.5 or later).

You can specify support for both with a flag like --with-sound=nas,esd (--enable-sound=nas,esd in 21.5 or later).

Q5.3.4: Sunsite sounds don't play.
----------------------------------

I'm having some trouble with sounds I've downloaded from sunsite.  They play when I run them through showaudio or cat them directly to /dev/audio, but XEmacs refuses to play them.

Markus Gutschke writes:

     [Many of] These files have an (erroneous) 24byte header that tells about the format that they have been recorded in. If you cat them to /dev/audio, the header will be ignored and the default behavior for /dev/audio will be used. This happens to be 8kHz uLaw. It is probably possible to fix the header by piping through sox and passing explicit parameters for specifying the sampling format; you then need to perform a 'null' conversion from SunAudio to SunAudio.

5.4: Running an Interior Shell, Invoking Subprocesses
=====================================================

Q5.4.1: What is an interior shell?
----------------------------------

#### Write me.

Q5.4.2: How do I start up a second shell buffer?
------------------------------------------------

In the *shell* buffer:

     M-x rename-buffer RET *shell-1* RET
     M-x shell RET

This will then start a second shell.  The key is that no buffer named *shell* can exist.  It might be preferable to use M-x rename-uniquely to rename the *shell* buffer instead of M-x rename-buffer.

Alternately, you can set the variable shell-multiple-shells. If the value of this variable is non-nil, each time shell mode is invoked, a new shell is made

Q5.4.3: Telnet from shell filters too much
------------------------------------------

I'm using the Emacs M-x shell function, and I would like to invoke and use a telnet session within it.  Everything works fine except that now all ^M's are filtered out by Emacs.  Fixes?

Use M-x rsh or M-x telnet to open remote sessions rather than doing rsh or telnet within the local shell buffer.  You can also use M-x ssh to open secure remote session if you have ssh installed.

Q5.4.4: Strange things are happening in Shell Mode.
---------------------------------------------------

Sometimes (i.e. it's not repeatable, and I can't work out why it happens) when I'm typing into shell mode, I hit return and only a portion of the command is given to the shell, and a blank prompt is returned.  If I hit return again, the rest of the previous command is given to the shell.

Martin Buchholz writes:

     There is a known problem with interaction between csh and the filec option and XEmacs.  You should add the following to your .cshrc:

          if ( "$TERM" == emacs || "$TERM" == unknown ) unset filec

Q5.4.5: XEmacs complains "No such file or directory, diff"
----------------------------------------------------------

or "ispell" or other commands that seem related to whatever you just tried to do (M-x ediff or M-$, for example).

There are a large number of common (in the sense that "everyone has these, they really do") Unix utilities that are not provided with XEmacs.  The GNU Project's implementations are available for Windows in the the Cygwin distribution (http://www.cygwin.com/), which also provides a complete Unix emulation environment (and thus makes ports of Unix utilities nearly trivial).  Another implementation is that from MinGW (http://www.mingw.org/msys.shtml).  If you know of others, please let us know!

Q5.4.6: Cygwin error "fork_copy: linked dll/bss pass 0 failed"
--------------------------------------------------------------

If you are getting an error like

     17797832 [main] bash 3468 fork_copy: linked dll/bss pass 0 failed,
     0x675000..0x6756A0, done 0, windows pid 2708, Win 32 error 487
     bash: fork: resource temporarily unavailable

when trying to run bash using M-x shell, then you need to rebase your Cygwin DLL's.  This is a known problem with Cygwin.  To fix:

 1. Download the rebase utility from Cygwin setup (it's under System).

 2. Kill all of your Cygwin processes, including all of your shells and all background processes.  Use ps -a to list all the processes you need to kill.

 3. From a DOS prompt, run ash (not bash, tcsh or zsh).  Do not try to be clever and exec /bin/ash from your last shell; it won't work.

 4. Type /bin/rebaseall -v.

The problem should now be fixed -- at least, until you install another Cygwin package with DLL's, in which case you may have to repeat the procedure.

5.5: Multiple Device Support
============================

Q5.5.1: How do I open a frame on another screen of my multi-headed display?
---------------------------------------------------------------------------

Use the command M-x make-frame-on-display.  This command is also on the File menu in the menubar.

The command make-frame-on-tty also exists, which will establish a connection to any tty-like device.  Opening the TTY devices should be left to gnuclient, though.

Q5.5.2: Can I really connect to a running XEmacs after calling up over a modem? How?
------------------------------------------------------------------------------------

Yes.  Use gnuclient -nw.

Also see How do I disable gnuserv from opening a new frame?.

Q5.5.3: How do I disable gnuserv from opening a new frame?
----------------------------------------------------------

If you set the gnuserv-frame variable to the frame that should be used to display buffers that are pulled up, a new frame will not be created. For example, you could put

     (setq gnuserv-frame (selected-frame))

early on in your init.el, to ensure that the first frame created is the one used for your gnuserv buffers.

There is an option to set the gnuserv target to the current frame.  See Options->Display->"Other Window" Location->Make Current Frame Gnuserv Target

You can also change this with Customize.  Select from the Options menu Advanced (Customize)->Emacs->Environment->Gnuserv->Gnuserv Frame...  or type M-x customize RET gnuserv RET.

Q5.5.4: How do I start gnuserv so that each subsequent XEmacs is a client?
--------------------------------------------------------------------------

Put the following in your init.el file to start the server:

     (gnuserv-start)

Start your first XEmacs as usual.  After that, you can do:

     gnuclient randomfilename

from the command line to get your existing XEmacs process to open a new frame and visit randomfilename in that window. When you're done editing randomfilename, hit C-x # to kill the buffer and get rid of the frame.

See also man page of gnuclient.

Q5.5.5: Is there a way to start a new XEmacs if there's no gnuserv running, and otherwise use gnuclient?
--------------------------------------------------------------------------------------------------------

Jan Vroonhof writes:

     Here is one of the solutions, we have this in a script called etc/editclient.sh.

           #!/bin/sh
           if gnuclient -batch -eval t >/dev/null 2>&1
           then
             exec gnuclient ${1+"$@"}
           else
             xemacs -unmapped -f gnuserv-start &
             until gnuclient -batch -eval t >/dev/null 2>&1
             do
                sleep 1
             done
             exec gnuclient ${1+"$@"}
           fi

     Note that there is a known problem when running XEmacs and 'gnuclient -nw' on the same TTY.

6 Connecting to the Internet
****************************

This is part 6 of the XEmacs Frequently Asked Questions list.  This section is devoted connecting to the Internet.

6.0: General Mail and News
==========================

Q6.0.1: What are the various packages for reading mail?
-------------------------------------------------------

#### Write me.

Q6.0.2: How can I send mail?
----------------------------

Under Unix and Mac OS X, the sendmail package is normally used for this. #### Write me.

Under Windows, you need to use smtpmail, which communicates directly with the mail server, as there is no sendmail program running.  To get it working, use code like the following in your init.el file:

       ;; Get mail working under Windows.
       (setq message-send-mail-function 'smtpmail-send-it) ; for message/Gnus
       (setq send-mail-function 'smtpmail-send-it) ; for C-x m, etc.
       ;; the following ensures that mail problems can be debugged: it logs a trace
       ;; of the SMTP conversation to *trace of SMTP session to <somewhere>*.
       (setq smtpmail-debug-info t)
       ;; Substitute your info here.
       ;(setq user-mail-address "ben@xemacs.org")
       ;(setq user-full-name "Ben Wing")
       ;(setq smtpmail-default-smtp-server "smtp.myserver.myisp.com")
       ;; The following two aren't completely necessary but may help.
       ;(setq smtpmail-local-domain "666.com")
       ;(setq smtpmail-sendto-domain "666.com")
       ;; If your SMTP server requires a username/password to authenticate, as
       ;; many do nowadays, set them like this:
       ;(setq smtpmail-auth-credentials  ; or use ~/.authinfo
       ;	'(("smtp.myserver.myisp.com" 25 "USER@SOMEWHERE" "PASSWORD")))

       ;; Other possibilities for getting smtpmail to work:
       ;;
       ;;  If for some reason you need to authenticate using the STARTTLS protocol
       ;;   (don't look into this unless you know what it is), use
       ;;  (setq smtpmail-starttls-credentials
       ;;      '(("YOUR SMTP HOST" 25 "~/.my_smtp_tls.key" "~/.my_smtp_tls.cert")))
       ;;  Requires external program
       ;;    ftp://ftp.opaopa.org/pub/elisp/starttls-*.tar.gz.
       ;;  See http://www.ietf.org/rfc/rfc2246.txt,
       ;;      http://www.ietf.org/rfc/rfc2487.txt

The lines you need to care about are those that set user-mail-address, user-full-name, smtpmail-default-smtp-server, and smtpmail-auth-credentials.  You need to set these with, respectively, your email address, your full name, the SMTP server you use for outgoing mail, and the username and password you need to log in to your SMTP server. (If for some reason your SMTP server doesn't require logging in to send mail, don't uncomment this last line.)

The other settings may be useful in specific cases, but you should know what you're doing before enabling them.

Q6.0.3: How do I get my outgoing mail archived?
-----------------------------------------------

     (setq mail-archive-file-name "~/outbox")

Q6.0.4: How can I read and/or compose MIME messages?
----------------------------------------------------

VM, MH-E and GNUS support MIME natively.  Other MUAs may or may not have MIME support; refer to their documentation and other resources, such as web pages and mailing lists.  Packages like SEMI/WEMI may be useful in connection with MUAs like mew and Wanderlust.

Q6.0.5: How do I customize the From line?
-----------------------------------------

How do I change the From: line?  I have set gnus-user-from-line to

     Gail Gurman <gail.gurman@sybase.com>

, but XEmacs Gnus doesn't use it. [This should apply to all MUA's. --ed] Instead it uses

     Gail Mara Gurman gailg@deall

and then complains that it's incorrect. Also, as you perhaps can see, my Message-ID is screwy. How can I change that?

Lars Magne Ingebrigtsen writes:

     Set user-mail-address to gail.gurman@sybase.com or mail-host-address to sybase.com.

Q6.0.6: How do I get my MUA to filter mail for me?
--------------------------------------------------

One possibility is to use procmail to split your mail before it gets to the MUA.  I prefer this personally, since there are many strange and wonderful things one can do with procmail.  Procmail may be found at http://www.procmail.org/.

Also see the Mail Filtering FAQ at: http://www.faqs.org/faqs/mail/filtering-faq/.

Q6.0.7: Remote mail reading with an MUA.
----------------------------------------

My mailbox lives at the office on a big honkin server.  My regular INBOX lives on my honkin desktop machine.  I now can PPP to the office from home which is far from honking...  I'd like to be able to read mail at home without storing it here and I'd like to use xemacs and the MUA at home...  Is there a recommended setup?

Joseph J. Nuspl Jr. writes:

     There are several ways to do this.

      1. Set your display to your home machine and run dxpc or one of the other X compressors.

      2. NFS mount your desktop machine on your home machine and modify your pop command on your home machine to rsh to your desktop machine and actually do the pop get's.

      3. Run a POP server on your desktop machine as well and do a sort of two tiered POP get.

William Perry adds:

     Or you could run a pop script periodically on your desktop machine, and just use ange-ftp or NFS to get to your mailbox.  I used to do this all the time back at IU.

Q6.0.8: An MUA gets an error incorporating new mail.
----------------------------------------------------

rmail and VM, and probably other MUA's as well, get new mail from your mailbox (called /var/mail/$USER or /var/spool/mail/$USER or something similar) using a program called movemail. This program interlocks with /bin/mail using the protocol defined by /bin/mail.

There are various different protocols in general use, which you need to specify using the --mail-locking option (--with-mail-locking in 21.5 or later) to configure:

lockf
     POSIX file locking with lockf()

flock
     BSD file locking with flock()

dot
     To manipulate mail file foo, first create file foo.lock

locking
     Use locking(), Microsoft's renamed flock()

mmdf
     Use lk_open() and lk_close() as defined by the Multi-channel Memo Distribution Facility

pop
     Retrieve mail using POP (the Post Office Protocol).  This is the default for Cygwin/MinGW.

IF YOU DON'T USE THE FORM OF INTERLOCKING THAT IS NORMAL ON YOUR SYSTEM, YOU CAN LOSE MAIL!

Usually the value is correctly determined automatically: configure tries to detect the method in use, and defaults exist on systems for which this doesn't work.

However, if you run into problems incorporating new mail, it may be because an incorrect method is being used.

If your system uses the lock file protocol, and permissions are set so that ordinary users cannot write lock files in the mail spool directory, you may need to make movemail setgid to a suitable group such as mail.  You can use these commands (as root):

     chgrp mail movemail
     chmod 2755 movemail

If you are using the pop locking method, movemail must be setuid root.

Installation normally copies movemail from the build directory to an installation directory which is usually under /usr/local/lib. The installed copy of movemail is usually in the directory /usr/local/lib/xemacs-VERSION/TARGET (for example, /usr/local/lib/xemacs-21.4.15/i686-pc-cygwin).  You must change the group and mode of the installed copy; changing the group and mode of the build directory copy is ineffective.

Q6.0.9: Why isn't movemail working?
-----------------------------------

See Q6.0.8.

Note also that older versions of Mozilla came with a movemail program that is not compatible with XEmacs.  Do not use it. Always use the movemail installed with your XEmacs.  Failure to do so can result in lost mail.

Q6.0.10: How do I make my MUA display graphical smilies?
--------------------------------------------------------

For mh-e use the following:

     (add-hook 'mh-show-mode-hook '(lambda ()
                                     (smiley-region (point-min)
                                                    (point-max))))

WJCarpenter writes: For VM use the following:

            (autoload 'smiley-region "smiley" nil t)
            (add-hook 'vm-select-message-hook
                      '(lambda ()
                         (smiley-region (point-min)
                                        (point-max))))

For tm use the following:

     (autoload 'smiley-buffer "smiley" nil t)
     (add-hook 'mime-viewer/plain-text-preview-hook 'smiley-buffer)

Q6.0.11: How can I get those oh-so-neat X-Face lines?
-----------------------------------------------------

Firstly there is an ftp site which describes X-faces and has the associated tools mentioned below, at http://ftp.cs.indiana.edu/pub/faces/.

Then the steps are

 1. Create 48x48x1 bitmap with your favorite tool

 2. Convert to "icon" format using one of xbm2ikon, pbmtoicon, etc., and then compile the face.

 3. cat file.xbm | xbm2ikon |compface > file.face

 4. Then be sure to quote things that are necessary for emacs strings:

          cat ./file.face | sed 's/\\/\\\\/g'
          | sed 's/\"/\\\"/g' > ./file.face.quoted

 5. Then set up emacs to include the file as a mail header - there were a couple of suggestions here---either something like:

          (setq  mail-default-headers
                 "X-Face:  Ugly looking text string here")

     Or, alternatively, as:

          (defun mail-insert-x-face ()
            (save-excursion
              (goto-char (point-min))
              (search-forward mail-header-separator)
              (beginning-of-line)
              (insert "X-Face:")
              (insert-file-contents "~/.face")))

          (add-hook 'mail-setup-hook 'mail-insert-x-face)

However, 2 things might be wrong:

Some versions of pbmtoicon produces some header lines that is not expected by the version of compface that I grabbed. So I found I had to include a tail +3 in the pipeline like this:

     cat file.xbm | xbm2ikon | tail +3 |compface > file.face

Some people have also found that if one uses the (insert-file) method, one should NOT quote the face string using the sed script .

It might also be helpful to use Stig's script xbm2face (included in the compface distribution at XEmacs.org) to do the conversion.

Contributors for this item:

Paul Emsley, Ricardo Marek, Amir J. Katz, Glen McCort, Heinz Uphoff, Peter Arius, Paul Harrison, and Vegard Vesterheim

6.1: Reading Mail with VM
=========================

Q6.1.1: How do I set up VM to retrieve mail from a remote site using POP?
-------------------------------------------------------------------------

Use vm-spool-files, like this for example:

     (setq vm-spool-files '("/var/spool/mail/wing"
                            "netcom23.netcom.com:110:pass:wing:MYPASS"))

Of course substitute your actual password for MYPASS.

Q6.1.2: How can I get VM to automatically check for new mail?
-------------------------------------------------------------

John Turner writes:

     Use the following:

          (setq vm-auto-get-new-mail 60)

Q6.1.3: I have various addresses at which I receive mail. How can I tell VM to ignore them when doing a "reply-all"?
--------------------------------------------------------------------------------------------------------------------

Set vm-reply-ignored-addresses to a list, like

     (setq vm-reply-ignored-addresses
           '("wing@nuspl@nvwls.cc.purdue.edu,netcom[0-9]*.netcom.com"
             "wing@netcom.com" "wing@xemacs.org"))

Note that each string is a regular expression.

Q6.1.4: Is there a mailing list or FAQ for VM?
----------------------------------------------

A FAQ for VM exists at http://www.wonderworks.com/vm/FAQ.html.

VM has its own newsgroups gnu.emacs.vm.info and gnu.emacs.vm.bug.

Q6.1.5: How do I make VM stay in a single frame?
------------------------------------------------

John.John S Cooper writes:

                                                  ; Don't use multiple frames
          (setq vm-frame-per-composition nil)
          (setq vm-frame-per-folder nil)
          (setq vm-frame-per-edit nil)
          (setq vm-frame-per-summary nil)

Q6.1.6: Customization of VM not covered in the manual, or here.
---------------------------------------------------------------

giacomo boffi writes:

     The meta-answer is to look into the file vm-vars.el, in the vm directory of the lisp library.

     vm-vars.el contains, initializes and carefully describes, with examples of usage, the plethora of user options that fully control VM's behavior.

     Enter vm-vars, forward-search for toolbar, find the variables that control the toolbar placement, appearance, existence, copy to your init.el or .vm and modify according to the detailed instructions.

     The above also applies to all the various features of VM: search for some keywords, maybe the first you conjure isn't appropriate, find the appropriate variables, copy and experiment.

6.2: Reading Netnews and Mail with Gnus
=======================================

Q6.2.1: GNUS, (ding) Gnus, Gnus 5, September Gnus, Red Gnus, Quassia Gnus, argh!
--------------------------------------------------------------------------------

The Gnus numbering issues are not meant for mere mortals to know them. If you feel you must enter the muddy waters of Gnus, visit the excellent FAQ, maintained by Justin Sheehy, at:

     http://my.gnus.org/FAQ/

See also Gnus home page

     http://www.gnus.org/

Q6.2.2: How do I make Gnus stay within a single frame?
------------------------------------------------------

The toolbar code to start Gnus opens the new frame---and it's a feature rather than a bug.  If you don't like it, but would still like to click on the seemly icon, use the following code:

     (defun toolbar-news ()
       (gnus))

It will redefine the callback function of the icon to just call gnus, without all the fancy frame stuff.

6.3: FTP Access
===============

Q6.3.1: Can I edit files on other hosts?
----------------------------------------

Yes.  Of course XEmacs can use any network file system (such as NFS or Windows file sharing) you have available, and includes some optimizations and safety features appropriate to those environments.

It is also possible to transparently edit files via FTP, ssh, or rsh.  That is, XEmacs makes a local copy using the transport in the background, and automatically refreshes the remote original from that copy when you save it.  XEmacs also is capable of doing file system manipulations like creating and removing directories and files.  The FTP interface is provided by the standard efs package EFS (efs).  The ssh/rsh interface is provided by the optional tramp package TRAMP (tramp).

Q6.3.2: What is EFS?
--------------------

#### Write me.

6.4: Web Browsing with W3
=========================

Q6.4.1: What is W3?
-------------------

W3 is an advanced graphical browser written in Emacs lisp that runs on XEmacs.  It has full support for cascaded style sheets, and more...

It has a home web page at http://www.cs.indiana.edu/elisp/w3/docs.html.

Q6.4.2: How do I run W3 from behind a firewall?
-----------------------------------------------

There is a long, well-written, detailed section in the W3 manual that describes how to do this.  Look in the section entitled "Firewalls".

Q6.4.3: Is it true that W3 supports style sheets and tables?
------------------------------------------------------------

Yes, and much more.  W3, as distributed with the latest XEmacs is a full-featured web browser.

7 Advanced Customization Using XEmacs Lisp
******************************************

This is part 7 of the XEmacs Frequently Asked Questions list.  This section is devoted to advanced customization using XEmacs Lisp.

7.0: Emacs Lisp and init.el
===========================

Q7.0.1: What version of Emacs am I running?
-------------------------------------------

How can init.el determine which of the family of Emacsen I am using?

To determine if you are currently running GNU Emacs 18, GNU Emacs 19, XEmacs 19, XEmacs 20, or Epoch, and use appropriate code, check out the example given in etc/sample.init.el (etc/sample.emacs in XEmacs versions prior to 21.4).  There are other nifty things in there as well!

For all new code, all you really need to do is:

     (defvar running-xemacs (string-match "XEmacs\\|Lucid" emacs-version))

Q7.0.2: How can I evaluate Emacs-Lisp expressions?
--------------------------------------------------

I know I can evaluate Elisp expressions from *scratch* buffer with C-j after the expression.  How do I do it from another buffer?

Press M-: (the default binding of eval-expression), and enter the expression to the minibuffer.

Q7.0.3: (setq tab-width 6) behaves oddly.
-----------------------------------------

If you put (setq tab-width 6) in your init.el file it does not work!  Is there a reason for this?  If you do it at the EVAL prompt it works fine!! How strange.

Use setq-default instead, since tab-width is all-buffer-local.

Q7.0.4: How can I add directories to the load-path?
---------------------------------------------------

Here are two ways to do that, one that puts your directories at the front of the load-path, the other at the end:

     ;;; Add things at the beginning of the load-path, do not add
     ;;; duplicate directories:
     (pushnew "bar" load-path :test 'equal)

     (pushnew "foo" load-path :test 'equal)

     ;;; Add things at the end, unconditionally
     (setq load-path (nconc load-path '("foo" "bar")))

keith (k.p.) hanlan writes:

     To add directories using Unix shell metacharacters use expand-file-name like this:

          (push (expand-file-name "~keithh/.emacsdir") load-path)

Q7.0.5: How to check if a lisp function is defined?
---------------------------------------------------

Use the following elisp:

     (fboundp 'foo)

It's almost always a mistake to test emacs-version or any similar variables.

Instead, use feature-tests, such as featurep, boundp, fboundp, or even simple behavioral tests, eg.:

     (defvar foo-old-losing-code-p
       (condition-case nil (progn (losing-code t) nil)
         (wrong-number-of-arguments t)))

There is an incredible amount of broken code out there which could work much better more often in more places if it did the above instead of trying to divine its environment from the value of one variable.

Q7.0.6: Can I force the output of (face-list) to a buffer?
----------------------------------------------------------

It would be good having it in a buffer, as the output of (face-list) is too wide to fit to a minibuffer.

Evaluate the expression in the *scratch* buffer with point after the rightmost paren and typing C-j.

If the minibuffer smallness is the only problem you encounter, you can simply press C-h l to get the former minibuffer contents in a buffer.

7.1: Emacs Lisp Programming Techniques
======================================

Q7.1.1: What is the difference in key sequences between XEmacs and GNU Emacs?
-----------------------------------------------------------------------------

Erik Naggum writes;

     Emacs has a legacy of keyboards that produced characters with modifier bits, and therefore map a variety of input systems into this scheme even today.  XEmacs is instead optimized for X events.  This causes an incompatibility in the way key sequences are specified, but both Emacs and XEmacs will accept a key sequence as a vector of lists of modifiers that ends with a key, e.g., to bind M-C-a, you would say [(meta control a)] in both Emacsen.  XEmacs has an abbreviated form for a single key, just (meta control a).  Emacs has an abbreviated form for the Control and the Meta modifiers to string-characters (the ASCII characters), as in \M-\C-a.  XEmacs users need to be aware that the abbreviated form works only for one-character key sequences, while Emacs users need to be aware that the string-character is rather limited.  Specifically, the string-character can accommodate only 256 different values, 128 of which have the Meta modifier and 128 of which have not.  In each of these blocks, only 32 characters have the Control modifier.  Whereas [(meta control A)] differs from [(meta control a)] because the case differs, \M-\C-a and \M-\C-A do not.  Programmers are advised to use the full common form, both because it is more readable and less error-prone, and because it is supported by both Emacsen.

Another (even safer) way to be sure of the key-sequences is to use the read-kbd-macro function, which takes a string like C-c <up>, and converts it to the internal key representation of the Emacs you use.  The function is available both on XEmacs and GNU Emacs.

Q7.1.2: Can I generate "fake" keyboard events?
----------------------------------------------

I wonder if there is an interactive function that can generate fake keyboard events.  This way, I could simply map them inside XEmacs.

This seems to work:

     (defun cg--generate-char-event (ch)
       "Generate an event, as if ch has been typed"
       (dispatch-event (character-to-event ch)))

     ;;  Backspace and Delete stuff
     (global-set-key [backspace]
       (lambda () (interactive) (cg--generate-char-event 127)))
     (global-set-key [unknown_keysym_0x4]
       (lambda () (interactive) (cg--generate-char-event 4)))

Q7.1.3: Could you explain read-kbd-macro in more detail?
--------------------------------------------------------

The read-kbd-macro function returns the internal Emacs representation of a human-readable string (which is its argument). Thus:

     (read-kbd-macro "C-c C-a")
     => [(control ?c) (control ?a)]

     (read-kbd-macro "C-c C-. <up>")
     => [(control ?c) (control ?.) up]

In GNU Emacs the same forms will be evaluated to what GNU Emacs understands internally---the sequences "\C-x\C-c" and [3 67108910 up], respectively.

The exact human-readable syntax is defined in the docstring of edmacro-mode.  I'll repeat it here, for completeness.

     Format of keyboard macros during editing:

     Text is divided into words separated by whitespace.  Except for the words described below, the characters of each word go directly as characters of the macro.  The whitespace that separates words is ignored.  Whitespace in the macro must be written explicitly, as in foo SPC bar RET.

       * The special words RET, SPC, TAB, DEL, LFD, ESC, and NUL represent special control characters.  The words must be written in uppercase.

       * A word in angle brackets, e.g., <return>, <down>, or <f1>, represents a function key.  (Note that in the standard configuration, the function key <return> and the control key RET are synonymous.)  You can use angle brackets on the words RET, SPC, etc., but they are not required there.

       * Keys can be written by their ASCII code, using a backslash followed by up to six octal digits.  This is the only way to represent keys with codes above \377.

       * One or more prefixes M- (meta), C- (control), S- (shift), A- (alt), H- (hyper), and s- (super) may precede a character or key notation.  For function keys, the prefixes may go inside or outside of the brackets: C-<down> == <C-down>.  The prefixes may be written in any order: M-C-x == C-M-x.

          Prefixes are not allowed on multi-key words, e.g., C-abc, except that the Meta prefix is allowed on a sequence of digits and optional minus sign: M--123 == M-- M-1 M-2 M-3.

       * The ^ notation for control characters also works: ^M == C-m.

       * Double angle brackets enclose command names: <<next-line>> is shorthand for M-x next-line RET.

       * Finally, REM or ;; causes the rest of the line to be ignored as a comment.

     Any word may be prefixed by a multiplier in the form of a decimal number and *: 3*<right> == <right> <right> <right>, and 10*foo == foofoofoofoofoofoofoofoofoofoo.

     Multiple text keys can normally be strung together to form a word, but you may need to add whitespace if the word would look like one of the above notations: ; ; ; is a keyboard macro with three semicolons, but ;;; is a comment.  Likewise, \ 1 2 3 is four keys but \123 is a single key written in octal, and < right > is seven keys but <right> is a single function key.  When in doubt, use whitespace.

Q7.1.4: What is the performance hit of let?
-------------------------------------------

In most cases, not noticeable.  Besides, there's no avoiding let---you have to bind your local variables, after all.  Some pose a question whether to nest lets, or use one let per function.  I think because of clarity and maintenance (and possible future implementation), let-s should be used (nested) in a way to provide the clearest code.

Q7.1.5: What is the recommended use of setq?
--------------------------------------------

  * Global variables

     You will typically defvar your global variable to a default value, and use setq to set it later.

     It is never a good practice to setq user variables (like case-fold-search, etc.), as it ignores the user's choice unconditionally.  Note that defvar doesn't change the value of a variable if it was bound previously.  If you wish to change a user-variable temporarily, use let:

          (let ((case-fold-search nil))
            ...                                   ; code with searches that must be case-sensitive
            ...)

     You will notice the user-variables by their docstrings beginning with an asterisk (a convention).

  * Local variables

     Bind them with let, which will unbind them (or restore their previous value, if they were bound) after exiting from the let form.  Change the value of local variables with setq or whatever you like (e.g. incf, setf and such).  The let form can even return one of its local variables.

     Typical usage:

          ;; iterate through the elements of the list returned by
          ;; `hairy-function-that-returns-list'
          (let ((l (hairy-function-that-returns-list)))
            (while l
              ... do something with (car l) ...
              (setq l (cdr l))))

     Another typical usage includes building a value simply to work with it.

          ;; Build the mode keymap out of the key-translation-alist
          (let ((inbox (file-truename (expand-file-name box)))
                (i 0))
            ... code dealing with inbox ...
            inbox)

     This piece of code uses the local variable inbox, which becomes unbound (or regains old value) after exiting the form.  The form also returns the value of inbox, which can be reused, for instance:

          (setq foo-processed-inbox
                (let .....))

Q7.1.6: What is the typical misuse of setq?
-------------------------------------------

A typical misuse is probably setqing a variable that was meant to be local.  Such a variable will remain bound forever, never to be garbage-collected.  For example, the code doing:

     (defun my-function (whatever)
       (setq a nil)
       ... build a large list ...
       ... and exit ...)

does a bad thing, as a will keep consuming memory, never to be unbound.  The correct thing is to do it like this:

     (defun my-function (whatever)
       (let (a)                              ; default initialization is to nil
         ... build a large list ...
         ... and exit, unbinding `a' in the process  ...)

Not only is this prettier syntactically, but it makes it possible for Emacs to garbage-collect the objects which a used to reference.

Note that even global variables should not be setqed without defvaring them first, because the byte-compiler issues warnings. The reason for the warning is the following:

     (defun flurgoze nil)                    ; ok, global internal variable
     ...

     (setq flurghoze t)                      ; ops!  a typo, but semantically correct.
                                             ; however, the byte-compiler warns.

     While compiling toplevel forms:
     ** assignment to free variable flurghoze

Q7.1.7: I like the do form of cl, does it slow things down?
-----------------------------------------------------------

It shouldn't.  Here is what Dave Gillespie has to say about cl.el performance:

     Many of the advanced features of this package, such as defun*, loop, and setf, are implemented as Lisp macros.  In byte-compiled code, these complex notations will be expanded into equivalent Lisp code which is simple and efficient.  For example, the forms

          (incf i n)
          (push x (car p))

     are expanded at compile-time to the Lisp forms

          (setq i (+ i n))
          (setcar p (cons x (car p)))

     which are the most efficient ways of doing these respective operations in Lisp.  Thus, there is no performance penalty for using the more readable incf and push forms in your compiled code.

     Interpreted code, on the other hand, must expand these macros every time they are executed.  For this reason it is strongly recommended that code making heavy use of macros be compiled.  (The features labelled Special Form instead of Function in this manual are macros.)  A loop using incf a hundred times will execute considerably faster if compiled, and will also garbage-collect less because the macro expansion will not have to be generated, used, and thrown away a hundred times.

     You can find out how a macro expands by using the cl-prettyexpand function.

Q7.1.8: I like recursion, does it slow things down?
---------------------------------------------------

Yes.  The Emacs byte-compiler cannot do much to optimize recursion.  But think well whether this is a real concern in Emacs.  Much of the Emacs slowness comes from internal mechanisms such as redisplay, or from the fact that it is an interpreter.

Please try not to make your code much uglier to gain a very small speed gain.  It's not usually worth it.

Q7.1.9: How do I put a glyph as annotation in a buffer?
-------------------------------------------------------

Here is a solution that will insert the glyph annotation at the beginning of buffer:

     (make-annotation (make-glyph '([FORMAT :file FILE]
                                    [string :data "fallback-text"]))
                      (point-min)
                      'text
                      (current-buffer))

Replace FORMAT with an unquoted symbol representing the format of the image (e.g. xpm, xbm, gif, jpeg, etc.) Instead of FILE, use the image file name (e.g. /usr/local/lib/xemacs-21.4/etc/recycle.xpm).

You can turn this to a function (that optionally prompts you for a file name), and inserts the glyph at (point) instead of (point-min).

Q7.1.10: map-extents won't traverse all of my extents!
------------------------------------------------------

I tried to use map-extents to do an operation on all the extents in a region.  However, it seems to quit after processing a random number of extents.  Is it buggy?

No.  The documentation of map-extents states that it will iterate across the extents as long as FUNCTION returns nil. Unexperienced programmers often forget to return nil explicitly, which results in buggy code.  For instance, the following code is supposed to delete all the extents in a buffer, and issue as many fubar! messages.

     (map-extents (lambda (ext ignore)
                    (delete-extent ext)
                    (message "fubar!")))

Instead, it will delete only the first extent, and stop right there -- because message will return a non-nil value.  The correct code is:

     (map-extents (lambda (ext ignore)
                    (delete-extent ext)
                    (message "fubar!")
                    nil))

Q7.1.11: My elisp program is horribly slow. Is there an easy way to find out where it spends time?
--------------------------------------------------------------------------------------------------

Hrvoje Niksic writes:

     Under XEmacs 20.4 and later you can use M-x profile-key-sequence, press a key (say RET in the Gnus Group buffer), and get the results using M-x profile-results.  It should give you an idea of where the time is being spent.

7.2: Mathematics
================

Q7.2.1: What are bignums, ratios, and bigfloats in Lisp?
--------------------------------------------------------

Thanks to Jerry James, XEmacs 21.5.18 and later can use the capabilities of multiple-precision libraries that may be available for your platform.  The GNU Multiple Precision (GMP) and BSD Multiple Precision (MP) libraries are partially supported.  GMP gives you bignums (arbitrary precision integers), ratios (arbitrary precision fractions), and bigfloats (arbitrary precision floating point numbers).  GNU MP is better-supported by XEmacs at the time of writing (2004-04-06).  BSD MP support does not include ratios or bigfloats, and it throws errors that aren't understood.

In most cases, bignum support should be transparent to users and Lisp programmers.  A bignum-enabled XEmacs will automatically convert from fixnums to bignums and back in pure integer arithmetic, and for GNU MP, from floats to bigfloats.  (Bigfloats must be explicitly coerced to other types, even if they are exactly representable by less precise types.)  The Lisp reader and printer have been enhanced to handle bignums, as have the mathematical functions.  Rationals (fixnums, bignums, and ratios) are printed using the %d, %o, %x, and %u format conversions.  The read syntax for ratios is 3/5.

User-visible changes in behavior include (in probable order of annoyance)

  * Arithmetic can cause a segfault, depending on your MP library XEmacs segfaults when I use very big numbers!.

  * Terminology is not Common-Lisp-conforming.  For example, ``integer'' for Emacs Lisp means what Common Lisp calls ``fixnum''.  This issue is being investigated, but the use of ``integer'' for fixnum is pervasive and may cause backward-compatibility and GNU-Emacs-compatibility problems.

  * Many operations that used to cause a range error now succeed, with intermediate results and return values coerced to bignums as needed.

  * An atom with ratio read syntax now returns a number, not a symbol.

  * The %u format conversion will now give an error if its argument is negative.  (Without MP, it prints a number which Lisp can't read.)

Surgeon General's Warning: The automatic conversions cannot be disabled at runtime.  New functions have been added which produce ratios, so there should be few surprises with type conflicts, but they can't be ruled out.  ``Arbitrary'' precision means precisely what it says.  If you work with extremely large numbers, your machine may arbitrarily decide to hand you an unpleasant surprise rather than a bignum XEmacs segfaults when I use very big numbers!.

To configure with GNU MP, add --use-number-lib=gmp (--enable-bignum=gmp in 21.5 or later) to your invocation of configure.  For BSD MP, use --use-number-lib=mp (--enable-bignum=mp for 21.5).

If you would like to help with bignum support, especially on BSD MP, please subscribe to the XEmacs Beta mailing list (http://www.xemacs.org/Lists/#xemacs-beta), and book up on number-gmp.h and number-mp.h.  Jerry has promised to write internals documentation eventually, but if your skills run more to analysis and documentation than to writing new code, feel free to fill in the gap!

Q7.2.2: XEmacs segfaults when I use very big numbers!
-----------------------------------------------------

GMP by default allocates temporaries on the stack.  If you run out of stack space, you're dead; there is no way that we know of to reliably detect this condition, because alloca is typically implemented to be fast rather than robust.  If you just need a little more oomph, use a bigger stack (e.g., the ulimit -s command in bash(1)).  If you want robustness at the cost of speed, configure GMP with --disable-alloca and rebuild the GMP library.

We do not know whether BSD MP uses alloca or not.  Please send any information you have as a bug report (M-x report-xemacs-bug RET), which will give us platform information.  (We do know that BSD MP implementations vary across vendors, but how much, we do not know yet.)

Q7.2.3: Bignums are really slow!
--------------------------------

Many Linux distributions compile all their packages for the i386, and this is costly.  An optimized version can give you two or three orders of magnitude better performance for a Pentium III or IV.  (Yes, really. See http://www.swox.com/gmp/gmp-speed.html.)

Q7.2.4: Equal bignums don't compare as equal! What gives?
---------------------------------------------------------

Ah, Grasshopper, I see you are using (eq x y).  The Bodhisattva CLTL2 warned of the illusion that equal numbers would be eq! Meditate on the deeper truths of eql, in which numbers of the same type which have equal values compare equal, and =, which does any necessary type coercions before comparing for equality.

Yeah, yeah, it has always worked for integer types, because fixnums and characters have an immediate representation.  Sorry about that; arbitrary precision obviously requires consing new objects because the objects are ``large'' and of variable size, and the definition of eq does not permit different objects to compare as equal.

8 Other External Packages
*************************

This is part 8 of the XEmacs Frequently Asked Questions list.  This section is devoted to miscellaneous external packages not covered elsewhere in XEmacs.

8.0: TeX
========

Q8.0.1: Is there something better than LaTeX mode?
--------------------------------------------------

David Kastrup writes:

     The standard TeX modes leave much to be desired, and are somewhat leniently maintained.  Serious TeX users use AUCTeX (see What is AUCTeX? Where do you get it?).

Q8.0.2: What is AUCTeX? Where do you get it?
--------------------------------------------

AUCTeX is a complex and sophisticated editing package dedicated to TeX and related text formatting languages, including LaTeX and Texinfo. It provides support for running TeX on a file or part of a file, include files, and of course shortcuts for entering common TeX macros, LaTeX environments, etc, and for fontlock.

AUCTeX is a standard package provided by XEmacs.  You can get it as usual through the M-x list-packages interface.  It is also included in the (non-Mule) SUMO package.  The AUCTeX XEmacs package is maintained by Uwe Brauer <GET MAIL ADDRESS>.

AUCTeX is extremely complicated, and its developers primarily use GNU Emacs.  Not all features of the bleeding edge version of AUCTeX are immediately ported to XEmacs; if you need these, you may be better off getting the most recent versions from the GNU AUCTeX project on http://savannah.gnu.org.

Q8.0.3: Problems installing AUCTeX.
-----------------------------------

Jan Vroonhof writes:

     AUCTeX works fine on both stock Emacs and XEmacs has been doing so for a very very long time. This is mostly due to the work of Per Abrahamsen (clap clap) in particular his easymenu package.  Which leads to what is probably the problem...

Most problems with AUCTeX are one of two things:

  * The TeX-lisp-directory in tex-site.el and the makefile don't match.

     Fix: make sure you configure AUCTeX properly before installing.

  * You have an old version of easymenu.el in your path.

     Fix: use locate-library and remove old versions to make sure it only finds the one that came with XEmacs.

Q8.0.4: How do I turn off current chapter from AUCTeX modeline?
---------------------------------------------------------------

With AUCTeX, fast typing is hard because the current chapter, section etc. are given in the modeline.  How can I turn this off?

It's not AUCTeX, it comes from func-menu in func-menu.el.

David Hughes writes:

     Try this; you'll still get the function name displayed in the modeline, but it won't attempt to keep track when you modify the file. To refresh when it gets out of synch, you simply need click on the Rescan Buffer option in the function-menu.

          (setq-default fume-auto-rescan-buffer-p nil)

8.1: Other Unbundled Packages
=============================

Q8.1.1: Is there a reason for an Emacs package not to be included in XEmacs?
----------------------------------------------------------------------------

The reason for an Emacs package not to be included in XEmacs is usually one or more of the following:

 1. The package has not been ported to XEmacs.  This will typically happen when it uses GNU-Emacs-specific features, which make it fail under XEmacs.

     Porting a package to XEmacs can range from a trivial amount of change to a partial or full rewrite.  Fortunately, the authors of modern packages usually choose to support both Emacsen themselves.

 2. The package has been decided not to be appropriate for XEmacs.  It may have an equivalent or better replacement within XEmacs, in which case the developers may choose not to burden themselves with supporting an additional package.

     Each package bundled with XEmacs means more work for the maintainers, whether they want it or not.  If you are ready to take over the maintenance responsibilities for the package you port, be sure to say so---we will more likely include it.

 3. The package simply hasn't been noted by the XEmacs development.  If that's the case, the messages like yours are very useful for attracting our attention.

 4. The package was noted by the developers, but they simply haven't yet gotten around to including/porting it.  Wait for the next release or, even better, offer your help.  It will be gladly accepted and appreciated.

Q8.1.2: Are there any Emacs Lisp Spreadsheets?
----------------------------------------------

Yes.  Check out dismal (which stands for Dis' Mode Ain't Lotus) at http://acs.ist.psu.edu/dismal/dismal.html.

Q8.1.3: Is there a MatLab mode?
-------------------------------

Yes, a matlab mode and other items are available at the http://www.mathworks.com/matlabcentral/files/104/matlab.el.

8.2: Environments Built Around XEmacs
=====================================

Q8.2.1: What are SPARCworks, EOS, and WorkShop?
-----------------------------------------------

SPARCworks was a development environment from Sun (circa 1993-1996) and consisted of compilers (C, C++, FORTRAN 77, Fortran 90, Ada, and Pascal), a debugger, and other tools such as TeamWare (for configuration management), MakeTool, etc.

EOS is the integration of XEmacs with the SPARCworks debugger.  It allows one to use an XEmacs frame to view code (complete with fontification, etc.), set breakpoints, print variables, etc., while using the SPARCworks debugger.

EOS stands for "Era on SPARCworks"; Era stood for "Emacs Rewritten Again" and was the name used by Sun for its modified version of Lucid Emacs (later XEmacs) in the early-mid 90's.  This is documented in more detail in the history section of the XEmacs About page.

EOS was replaced around 1996 with a newer graphical development environment called Sun WorkShop.  The current status of this is unknown.

Q8.2.2: How do I start the Sun Workshop support in XEmacs 21?
-------------------------------------------------------------

Add the switch ---with-workshop to the configure command when building XEmacs and put the following in one of your startup files (e.g. site-start.el or .emacs):

     (when (featurep 'tooltalk)
       (load "tooltalk-macros")
       (load "tooltalk-util")
       (load "tooltalk-init"))
     (when (featurep 'sparcworks)
       (load "sunpro-init")
       (load "ring")
       (load "comint")
       (load "annotations")
       (sunpro-startup))

If you are not using the latest Workshop (5.0) you have to apply the following patch:

     --- /opt/SUNWspro/lib/eserve.el.ORIG    Fri May 14 15:23:26 1999
     +++ /opt/SUNWspro/lib/eserve.el Fri May 14 15:24:54 1999
     @@ -42,7 +42,7 @@
      (defvar running-xemacs nil "t if we're running XEmacs")
      (defvar running-emacs  nil "t if we're running GNU Emacs 19")

     -(if (string-match "^\\(19\\|20\\)\..*\\(XEmacs\\|Lucid\\)" emacs-version)
     +(if (string-match "\\(XEmacs\\|Lucid\\)" emacs-version)
          (setq running-xemacs t)
          (setq running-emacs  t))

Q8.2.3: What is/was Energize?
-----------------------------

The "Energize Programming System" was a C and C++ development environment sold by Lucid, Inc.  It was the reason why Lucid Emacs, now XEmacs, was created in the first place.  Unfortunately, Lucid went out of business in 1994.  The rights to sell it in Japan were purchased by INS Engineering (which briefly employed Stig Hackvan aka Jonathan Stigelman to work on Japanese support for XEmacs, in late 1994 and early 1995) and Tartan bought the rights to sell it in the rest of the world.  However, INS is not selling Energize at this point and may or may not have ever done so; Tartan certainly never did.

Q8.2.4: What is Infodock?
-------------------------

InfoDock (http://sourceforge.net/projects/infodock/) is an integrated productivity toolset, mainly aimed at technical people, hosted at SourceForge.

InfoDock is built atop the XEmacs variant of GNU Emacs and so has all of the power of Emacs, but with an easier to use and more comprehensive menu-based user interface.  The bottom portion of this text describes how it differs from XEmacs and GNU Emacs from the Free Software Foundation.

InfoDock is aimed at people who want a free, turn-key productivity environment.  Although InfoDock is customizable, it is not intended for people who like basic versions of Emacs which need to be customized extensively for local use; standard Emacs distributions are better for such uses.  InfoDock is for those people who want a complete, pre-customized environment in one package, which they need not touch more than once or twice a year to update to new revisions.

InfoDock is pre-built for SPARC SunOS/Solaris systems, PA-RISC HP-UX, and Intel Linux systems.  It is intended for use on a color display, although most features will work on monochrome monitors.  Simply unpack InfoDock according to the instructions in the ID-INSTALL file and you are ready to run.

The InfoDock Manual is concise, yet sufficient as a user guide for users who have never used an Emacs-type editor before.  For users who are already familiar with Emacs, it supplements the information in the GNU Emacs Manual.

InfoDock menus are much more extensive and more mature than standard Emacs menus.  Each menu offers a Manual item which displays documentation associated with the menu's functions.

Four types of menubars are provided:

 1. An extensive menubar providing access to global InfoDock commands.

 2. Mode-specific menubars tailored to the current major mode.

 3. A simple menubar for basic editing to help novices get started with InfoDock.

 4. The standard XEmacs menubar.

Most modes also include mode-specific popup menus.  Additionally, region and rectangle popup menus are included.

Hyperbole, the everyday information manager, is a core part of InfoDock.  This provides context-sensitive mouse keys, a rolodex-type contact manager, programmable hypertext buttons, and an autonumbered outliner with embedded hyperlink anchors.

The OO-Browser, a multi-language object-oriented code browser, is a standard part of InfoDock.

InfoDock saves a more extensive set of user options than other Emacs versions.

InfoDock inserts a useful file header in many file types, showing the author, summary, and last modification time of each file.  A summary program can then be used to summarize all of the files in a directory, for easy MANIFEST file creation.

Your working set of buffers is automatically saved and restored (if you answer yes to a prompt) between InfoDock sessions.

Refined color choices for code highlighting are provided for both dark and light background display frames.

The C-z key prefix performs frame-based commands which parallel the C-x key prefix for window-based commands.

The Smart Menu system is included for producing command menus on dumb terminals.

Lisp libraries are better categorized according to function.

Extensions and improvements to many areas of Emacs are included, such as: paragraph filling, mail reading with Rmail, shell handling, outlining, code highlighting and browsing, and man page browsing.

InfoDock questions, answers and discussion should go to the mail list infodock@infodock.com.  Use infodock-request@infodock.com to be added or removed from the list.  Always include your InfoDock version number when sending help requests.

9 What the Future Holds
***********************

This is part 9 of the XEmacs Frequently Asked Questions list.  This section will change frequently, and (in theory) should contain any interesting items that have transpired recently. (But in practice it's not getting updated like this.)

This section also contains descriptions of the new features in all the recent releases of XEmacs.  For the most part, the information below is a synopsis of the more complete information that can be found in the file NEWS in the etc directory of the XEmacs distribution. You can view this file in XEmacs using C-h n or the Help menu.

Information on older versions of XEmacs can be find in ONEWS in the same directory, or OONEWS for really old versions.

9.0: Changes
============

Q9.0.1: What new features will be in XEmacs soon?
-------------------------------------------------

#### Write me.

Q9.0.2: What's new in XEmacs 21.4?
----------------------------------

21.4 was the "stable" version of the 21.2 series, which was considered "experimental" throughout its life; thus there were no "official" releases at all.  In essence, XEmacs is now following the "alternating" scheme of Linux, where at any point there are at least two different development branches, one "stable" and one "experimental".  Periodic releases happen in both branches, but those in the experimental branch are not tested as well, and there's no guarantee they will work at all. The experiemental branch is open to any and all code that's acceptable to the developers; the stable branch, however, is in general limited only to bug fixes, and all contributions are carefully reviewed to make sure they will increase and not decrease stability.

21.3 never existed at all; it was decided to follow the Linux scheme exactly, where odd-numbered series are experimental and even-numbered ones stable.

The following lists summarizes the essential changes made in this version.  For a fuller list, see the NEWS in the etc directory of the XEmacs distribution, or use C-h n or the Help menu to view this file inside of XEmacs.

User-visible changes in XEmacs 21.4
...................................

  * The delete key now deletes forward by default.

  * Shifted motion keys now select text by default.

  * You can now build XEmacs with support for GTK+ widget set.

  * ~/.xemacs/init.el is now the preferred location for the init file. (XEmacs now supports a `~/.xemacs/init.el' startup file. Custom file will move to ~/.xemacs/custom.el.)

  * Much-improved sample init.el, showing how to use many useful features.

  * XEmacs support for menu accelerators has been much improved.

  * Default menubar improvements. (Default menubar has many new commands and better organization.  The font-menu is now available under MS Windows.)

  * Dialog box improvements, including a real file dialog box. (XEmacs now has a proper file dialog box under MS Windows (and GTK)!  The old clunky file dialog box is improved.  Keyboard traversal now works correctly in MS Windows dialog boxes.  There is a Search dialog box available from Edit->Find...)

  * New buffer tabs.

  * There is a new MS Windows installer, netinstall, ported from Cygwin.

  * The subprocess quote-handling mechanism under Windows is much improved.

  * Printing support now available under MS Windows.

  * Selection improvements. (Kill and yank now interact with the clipboard under Windows.  MS Windows support for selection is now much more robust.  Motif selection support is now more correct (but slower).)

  * Mail spool locking now works correctly.

  * International support changes. (The default coding-priority-list is now safer.  International keysyms are now supported under X.  MS Windows 1251 code page now supported.  Czech, Thai, Cyrillic-KOI8, Vietnamese, Ethiopic now supported.  Proper support for words in Latin 3 and Latin 4.)

  * Help buffers contain hyperlinks, and other changes.

  * The modeline's text is now scrollable.

  * The mouse wheel under MS Windows now functions correctly.

  * Interactive searching and matching case improvements. (Incremental search will now highlight all visible matches.  Interactive searches always respect uppercase characters.)

  * Rectangle functions rewritten to avoid inserting extra spaces.

  * New command `kill-entire-line' that always kills the entire line.

  * Default values correctly stored in minibuffer histories.

  * You can now create "indirect buffers", like in GNU Emacs.

  * Pixel-based scrolling has been implemented.

  * Operation progress can be displayed using graphical widgets.

  * User names following a tilde can now be completed at file name prompts.

  * XEmacs can now play sound using Enlightenment Sound Daemon (ESD).

  * X-Face support is now available under MS Windows.

  * The PostgreSQL Relational Database Management System is now supported.

  * Indentation no longer indents comments that begin at column zero.

  * Face and variable settings can have comments in Customize.

  * New locations for early package hierarchies.

  * The `auto-save' library has been greatly improved.

  * New variable `mswindows-alt-by-itself-activates-menu'.

  * Other init-file-related changes. (Init file in your home directory may be called `.emacs.el'.  New command-line switches -user-init-file and -user-init-directory.)

  * Etags changes.  See NEWS for full details.

Lisp and internal changes in XEmacs 21.4
........................................

Not yet written.

Q9.0.3: What's new in XEmacs 21.1?
----------------------------------

21.1 was the "stable" version of "experimental" 21.0 series. See What's new in XEmacs 21.4?.

The following lists summarizes the essential changes made in this version.  For a fuller list, see the NEWS in the etc directory of the XEmacs distribution, or use C-h n or the Help menu to view this file inside of XEmacs.

User-visible changes in XEmacs 21.1
...................................

  * XEmacs is now supported under Microsoft Windows 95/98 and Windows NT/2000/XP operating systems.  To discuss Windows-specific issues, subscribe to the mailing list at xemacs-winnt-request@xemacs.org.

  * XEmacs has been unbundled into constituent installable packages.

  * Other notable changes: The Options menu has been ported to Custom; XEmacs now is able to choose X visuals and use private colormaps; You can drag the vertical divider of "horizontally" (side-by-side) split windows.

  * Building changes: XEmacs can be built with support for 31-bit Lisp integers and 32-bit pointers (previously, it was 28-bit integers and pointers); XEmacs can be built with LDAP support; dir files can be removed in the Info subsystem, and will be regenerated on-the-fly.

  * New packages: imenu, popper, gdb-highlight

  * Package changes: Many changes to cc-mode, gnus, gnuclient.  See NEWS for full details.

  * New commands, variables and functions: center-to-window-line (like recenter but doesn't force a redisplay); variable user-full-name (customize what your full name looks like in mail); M-x customize-changed-options (customize options whose default values changes because you upgraded your XEmacs); M-x add-log-convert (converts an old-style ChangeLog buffer to new-style); M-x zap-up-to-char (like zap-to-char but doesn't delete the char searched for); commands to store, retrieve and increment numbers in registers, useful for macros.

  * Changes to commands, variables, and functions: M-x query-replace and friends operate only on the region when it's active; echo-keystrokes can now be a floating-point number; M-. searches exact tag matches before inexact ones; function user-full-name with no arguments returns the var user-full-name; a prefix arg to M-: and C-h c inserts the result in the current buffer.

  * Other changes: Under X, new application class XEmacs; byte-compilation of user-specs now works.

  * XEmacs/Mule (internationalization) changes: Mule support now works on TTY's; Egg/SJ3 input method now officially supported (Quail and Egg/Skk already available through LEIM since 20.3); localized Japanese menubars if XEmacs is built with the right support.

Lisp and internal changes in XEmacs 21.1
........................................

  * Specifier changes: The window locale now has a higher precedence than the buffer locale when instantiating; new macro let-specifier; new specifiers vertical-scrollbar-visible-p, horizontal-scrollbar-visible-p', scrollbar-on-left-p, scrollbar-on-top-p, vertical-divider-always-visible-p, vertical-divider-shadow-thickness, vertical-divider-line-width, vertical-divider-spacing; specifiers and symbols whose value is a specifier allowed as modeline specifications.

  * Frame focus changes: focus-follows-mouse works like FSF, prevents any attempt to permanently change the selected frame; new function focus-frame sets the window system focus a frame; new special forms save-selected-frame and with-selected-frame.

  * Window function changes: select-window now has optional argument NORECORD to inhibit recording a buffer change; vertical-motion now correctly handles optional WINDOW argument and has new optional argument PIXELS, to have the returned values be in pixels; new function vertical-motion-pixels; new functions window-text-area-pixel-{width,height,edges}; new functions shrink-window-pixels and enlarge-window-pixels; new function window-displayed-text-pixel-height.

  * Other function changes: Arithmetic comparison functions <, >, =, /= now accept a variable number of arguments; hashtables now have a consistent read/print syntax; keyword symbols cannot be set to a value other than themselves; concat no longer accepts integer arguments; new function string, like list, vector, etc.; new function temp-directory (OS-independent way to get a temp directory); load-average has optional argument USE-FLOATS; make-event implemented completely; new function function-interactive (returns a function's interactive spec); new functions lmessage, lwarn (printf-like versions of display-wessage, display-warning); new keyword :version to defcustom.

  * Performance: when the new GNU Malloc aka Doug Lea Malloc is available, it will be used (better performance on libc6 Linux systems); tracking line-numbers in modeline is now efficient; profiling records a call-count of all called functions, retrievable through profile-call-count-results.

  * Startup and path searching: code to assemble paths at startup rewritten for new package system; new function split-path (splits by path-separator); Info-default-directory-list obsolete, use Info-directory-list instead; site-lisp is deprecated and no longer on the load-path by default.

Q9.0.4: What's new in XEmacs 20.4?
----------------------------------

XEmacs 20.4 is a bugfix release with no user-visible changes.

Q9.0.5: What's new in XEmacs 20.3?
----------------------------------

XEmacs 20.3 was released in November 1997. It contains many bugfixes, and a number of new features, including Autoconf 2 based configuration, additional support for Mule (Multi-language extensions to Emacs), many more customizations, multiple frames on TTY-s, support for multiple info directories, an enhanced gnuclient, improvements to regexp matching, increased MIME support, and many, many synches with GNU Emacs 20.

The XEmacs/Mule support has been only seriously tested in a Japanese locale, and no doubt many problems still remain.  The support for ISO-Latin-1 and Japanese is fairly strong.  MULE support comes at a price---about a 30% slowdown from 19.16.  We're making progress on improving performance and XEmacs 20.3 compiled without Mule (which is the default) is definitely faster than XEmacs 19.16.

XEmacs 20.3 is the first non-beta v20 release, and will be the basis for all further development.

Q9.0.6: What's new in XEmacs 20.2?
----------------------------------

The biggest changes in 20.2 include integration of EFS (the next generation of ange-ftp) and AUC Tex (the Emacs subsystem that includes a major mode for editing Tex and LaTeX, and a lot of other stuff).  Many bugs from 20.0 have been fixed for this release.  20.2 also contains a new system for customizing XEmacs options, invoked via M-x customize.

XEmacs 20.2 is the development release (20.0 was beta), and is no longer considered unstable.

For older news, see the file ONEWS in the etc directory of the XEmacs distribution.

10 New information about old XEmacsen
*************************************

This is part 10 of the XEmacs Frequently Asked Questions list.  It will occasionally be updated to reflect new information about versions which are no longer being revised by the XEmacs Project.  The primary purpose is advice on compatibility of older XEmacsen with new packages and updated versions of packages, but bug fixes (which will not be applied to released XEmacsen, but users can apply themselves) are also accepted.

10.0: XEmacs 21.1
=================

Q10.0.1: Gnus 5.10 won't display smileys in XEmacs 21.1.
--------------------------------------------------------

Eric Eide wrote:

     Previously I wrote:

     Eric> Summary: with Gnus 5.10.1 in XEmacs 21.1.14, I don't see Eric> any smileys :-(.

     After a bit of sleuthing, I discovered the essence of the problem. For me, the form:

              	(with-temp-buffer
              	  (insert-file-contents "foo.xpm")
              	  (buffer-string))

     returns the empty string.  This is because something somewhere replaces the XPM data with a glyph --- I haven't figured out where this occurs.

Kyle Jones replies:

     Do this:

              (setq format-alist nil)

     The image-mode stuff is gone from format-alist in the 21.4 branch, praise be.

Q10.0.2: XEmacs won't start on Windows in XEmacs 21.1.
------------------------------------------------------

XEmacs relies on a process called "dumping" to generate a working executable. Under MS-Windows this process effectively fixes the memory addresses of information in the executable. When XEmacs starts up it tries to reserve these memory addresses so that the dumping process can be reversed -- putting the information back at the correct addresses. Unfortunately some .DLLs (for instance the soundblaster driver) occupy memory addresses that can conflict with those needed by the dumped XEmacs executable. In this instance XEmacs will fail to start without any explanation. Note that this is extremely machine specific.

21.1.10 includes a fix for this that makes more intelligent guesses about which memory addresses will be free, and this should cure the problem for most people.  21.4 implements "portable dumping", which eliminates the problem altogether.  We recommend you use the 21.4 binaries, but you can use the 21.1 binaries if you are very paranoid about stability.  See Are binaries available?.