@node Customization, Quitting, Emulation, Top
@chapter Customization
@cindex customization

  This chapter talks about various topics relevant to adapting the
behavior of Emacs in minor ways.

  All kinds of customization affect only the particular Emacs job that you
do them in.  They are completely lost when you kill the Emacs job, and have
no effect on other Emacs jobs you may run at the same time or later.  The
only way an Emacs job can affect anything outside of it is by writing a
file; in particular, the only way to make a customization `permanent' is to
put something in your @file{.emacs} file or other appropriate file to do the
customization in each session.  @xref{Init File}.

@menu
* Minor Modes::     Each minor mode is one feature you can turn on
                     independently of any others.
* Variables::       Many Emacs commands examine Emacs variables
                     to decide what to do; by setting variables,
                     you can control their functioning.
* Keyboard Macros:: A keyboard macro records a sequence of keystrokes
                     to be replayed with a single command.
* Key Bindings::    The keymaps say what command each key runs.
                     By changing them, you can "redefine keys".
* Syntax::          The syntax table controls how words and expressions
                     are parsed.
* Init File::       How to write common customizations in the @file{.emacs} 
                     file.
* Audible Bell::    Changing how Emacs sounds the bell. 
* Faces::           Changing the fonts and colors of a region of text. 
* X Resources::	    X resources controlling various aspects of the
                     behavior of XEmacs.
@end menu

@node Minor Modes
@section Minor Modes
@cindex minor modes

@cindex mode line
  Minor modes are options which you can use or not.  For example, Auto
Fill mode is a minor mode in which @key{SPC} breaks lines between words
as you type.  All the minor modes are independent of each other and of
the selected major mode.  Most minor modes inform you in the mode line
when they are on; for example, @samp{Fill} in the mode line means that
Auto Fill mode is on.

  Append @code{-mode} to the name of a minor mode to get the name of a
command function that turns the mode on or off.  Thus, the command to
enable or disable Auto Fill mode is called @kbd{M-x auto-fill-mode}.  These
commands are usually invoked with @kbd{M-x}, but you can bind keys to them
if you wish.  With no argument, the function turns the mode on if it was
off and off if it was on.  This is known as @dfn{toggling}.  A positive
argument always turns the mode on, and an explicit zero argument or a
negative argument always turns it off.

@cindex Auto Fill mode
@findex auto-fill-mode
  Auto Fill mode allows you to enter filled text without breaking lines
explicitly.  Emacs inserts newlines as necessary to prevent lines from
becoming too long.  @xref{Filling}.

@cindex Overwrite mode
@findex overwrite-mode
  Overwrite mode causes ordinary printing characters to replace existing
text instead of moving it to the right.  For example, if point is in
front of the @samp{B} in @samp{FOOBAR}, and you type a @kbd{G} in Overwrite
mode, it changes to @samp{FOOGAR}, instead of @samp{FOOGBAR}.@refill

@cindex Abbrev mode
@findex abbrev-mode
  Abbrev mode allows you to define abbreviations that automatically expand
as you type them.  For example, @samp{amd} might expand to @samp{abbrev
mode}.  @xref{Abbrevs}, for full information.

@node Variables
@section Variables
@cindex variable
@cindex option

  A @dfn{variable} is a Lisp symbol which has a value.  Variable names
can contain any characters, but by convention they are words separated
by hyphens.  A variable can also have a documentation string, which
describes what kind of value it should have and how the value will be
used.

  Lisp allows any variable to have any kind of value, but most variables
that Emacs uses require a value of a certain type.  Often the value has
to be a string or a number.  Sometimes we say that a certain feature is
turned on if a variable is ``non-@code{nil},'' meaning that if the
variable's value is @code{nil}, the feature is off, but the feature is
on for @i{any} other value.  The conventional value to turn on the
feature---since you have to pick one particular value when you set the
variable---is @code{t}.

  Emacs uses many Lisp variables for internal recordkeeping, as any Lisp
program must, but the most interesting variables for you are the ones that
exist for the sake of customization.  Emacs does not (usually) change the
values of these variables; instead, you set the values, and thereby alter
and control the behavior of certain Emacs commands.  These variables are
called @dfn{options}.  Most options are documented in this manual and
appear in the Variable Index (@pxref{Variable Index}).

  One example of a variable which is an option is @code{fill-column}, which
specifies the position of the right margin (as a number of characters from
the left margin) to be used by the fill commands (@pxref{Filling}).

@menu
* Examining::           Examining or setting one variable's value.
* Edit Options::        Examining or editing list of all variables' values.
* Locals::              Per-buffer values of variables.
* File Variables::      How files can specify variable values.
@end menu

@node Examining
@subsection Examining and Setting Variables
@cindex setting variables

@table @kbd
@item C-h v
@itemx M-x describe-variable
Print the value and documentation of a variable.
@findex set-variable
@item M-x set-variable
Change the value of a variable.
@end table

@kindex C-h v
@findex describe-variable
  To examine the value of a single variable, use @kbd{C-h v}
(@code{describe-variable}), which reads a variable name using the
minibuffer, with completion.  It prints both the value and the
documentation of the variable.

@example
C-h v fill-column @key{RET}
@end example

@noindent
prints something like:

@smallexample
fill-column's value is 75

Documentation:
*Column beyond which automatic line-wrapping should happen.
Automatically becomes local when set in any fashion.
@end smallexample

@cindex option
@noindent
The star at the beginning of the documentation indicates that this variable
is an option.  @kbd{C-h v} is not restricted to options; it allows any
variable name.

@findex set-variable
  If you know which option you want to set, you can use @kbd{M-x
set-variable} to set it.  This prompts for the variable name in the
minibuffer (with completion), and then prompts for a Lisp expression for the
new value using the minibuffer a second time.  For example,

@example
M-x set-variable @key{RET} fill-column @key{RET} 75 @key{RET}
@end example

@noindent
sets @code{fill-column} to 75, as if you had executed the Lisp expression
@code{(setq fill-column 75)}.

  Setting variables in this way, like all means of customizing Emacs
except where explicitly stated, affects only the current Emacs session.

@node Edit Options
@subsection Editing Variable Values

@table @kbd
@item M-x list-options
Display a buffer listing names, values, and documentation of all options.
@item M-x edit-options
Change option values by editing a list of options.
@end table

@findex list-options
  @kbd{M-x list-options} displays a list of all Emacs option variables in
an Emacs buffer named @samp{*List Options*}.  Each option is shown with its
documentation and its current value.  Here is what a portion of it might
look like:

@smallexample
;; exec-path:
("." "/usr/local/bin" "/usr/ucb" "/bin" "/usr/bin" "/u2/emacs/etc")
*List of directories to search programs to run in subprocesses.
Each element is a string (directory name)
or nil (try the default directory).
;;
;; fill-column:
75
*Column beyond which automatic line-wrapping should happen.
Automatically becomes local when set in any fashion.
;;
@end smallexample

@findex edit-options
  @kbd{M-x edit-options} goes one step further and immediately selects the
@samp{*List Options*} buffer; this buffer uses the major mode Options mode,
which provides commands that allow you to point at an option and change its
value:

@table @kbd
@item s
Set the variable point is in or near to a new value read using the
minibuffer.
@item x
Toggle the variable point is in or near: if the value was @code{nil},
it becomes @code{t}; otherwise it becomes @code{nil}.
@item 1
Set the variable point is in or near to @code{t}.
@item 0
Set the variable point is in or near to @code{nil}.
@item n
@itemx p
Move to the next or previous variable.
@end table

@node Locals
@subsection Local Variables

@table @kbd
@item M-x make-local-variable
Make a variable have a local value in the current buffer.
@item M-x kill-local-variable
Make a variable use its global value in the current buffer.
@item M-x make-variable-buffer-local
Mark a variable so that setting it will make it local to the
buffer that is current at that time.
@end table

@cindex local variables
   You can make any variable @dfn{local} to a specific Emacs buffer.
This means that the variable's value in that buffer is independent of
its value in other buffers.  A few variables are always local in every
buffer.  All other Emacs variables have a @dfn{global} value which is in
effect in all buffers that have not made the variable local.

  Major modes always make the variables they set local to the buffer.
This is why changing major modes in one buffer has no effect on other
buffers.

@findex make-local-variable
  @kbd{M-x make-local-variable} reads the name of a variable and makes it
local to the current buffer.  Further changes in this buffer will not
affect others, and changes in the global value will not affect this
buffer.

@findex make-variable-buffer-local
@cindex per-buffer variables
  @kbd{M-x make-variable-buffer-local} reads the name of a variable and
changes the future behavior of the variable so that it automatically
becomes local when it is set.  More precisely, once you have marked a
variable in this way, the usual ways of setting the
variable will automatically invoke @code{make-local-variable} first.  We
call such variables @dfn{per-buffer} variables.

  Some important variables have been marked per-buffer already.  They
include @code{abbrev-mode}, @code{auto-fill-function},
@code{case-fold-search}, @code{comment-column}, @code{ctl-arrow},
@code{fill-column}, @code{fill-prefix}, @code{indent-tabs-mode},
@code{left-margin}, @*@code{mode-line-format}, @code{overwrite-mode},
@code{selective-display-ellipses}, @*@code{selective-display},
@code{tab-width}, and @code{truncate-lines}.  Some other variables are
always local in every buffer, but they are used for internal
purposes.@refill

Note: the variable @code{auto-fill-function} was formerly named
@code{auto-fill-hook}.

@findex kill-local-variable
  If you want a variable to cease to be local to the current buffer,
call @kbd{M-x kill-local-variable} and provide the name of a variable to
the prompt.  The global value of the variable
is again in effect in this buffer.  Setting the major mode kills all
the local variables of the buffer.

@findex setq-default
  To set the global value of a variable, regardless of whether the
variable has a local value in the current buffer, you can use the
Lisp function @code{setq-default}.  It works like @code{setq}.
If there is a local value in the current buffer, the local value is
not affected by @code{setq-default}; thus, the new global value may
not be visible until you switch to another buffer, as in the case of:

@example
(setq-default fill-column 75)
@end example

@noindent
@code{setq-default} is the only way to set the global value of a variable
that has been marked with @code{make-variable-buffer-local}.

@findex default-value
  Programs can look at a variable's default value with @code{default-value}.
This function takes a symbol as an argument and returns its default value.
The argument is evaluated; usually you must quote it explicitly, as in
the case of:

@example
(default-value 'fill-column)
@end example

@node File Variables
@subsection Local Variables in Files
@cindex local variables in files

  A file can contain a @dfn{local variables list}, which specifies the
values to use for certain Emacs variables when that file is edited.
Visiting the file checks for a local variables list and makes each variable
in the list local to the buffer in which the file is visited, with the
value specified in the file.

  A local variables list goes near the end of the file, in the last page.
(It is often best to put it on a page by itself.)  The local variables list
starts with a line containing the string @samp{Local Variables:}, and ends
with a line containing the string @samp{End:}.  In between come the
variable names and values, one set per line, as @samp{@var{variable}:@:
@var{value}}.  The @var{value}s are not evaluated; they are used literally.

  The line which starts the local variables list does not have to say
just @samp{Local Variables:}.  If there is other text before @samp{Local
Variables:}, that text is called the @dfn{prefix}, and if there is other
text after, that is called the @dfn{suffix}.  If a prefix or suffix are
present, each entry in the local variables list should have the prefix
before it and the suffix after it.  This includes the @samp{End:} line.
The prefix and suffix are included to disguise the local variables list
as a comment so the compiler or text formatter  will ignore it.
If you do not need to disguise the local variables list as a comment in
this way, there is no need to include a prefix or a suffix.@refill

  Two ``variable'' names are special in a local variables list: a value
for the variable @code{mode} sets the major mode, and a value for the
variable @code{eval} is simply evaluated as an expression and the value
is ignored.  These are not real variables; setting them in any other
context does not have the same effect.  If @code{mode} is used in a
local variables list, it should be the first entry in the list.

Here is an example of a local variables list:
@example
;;; Local Variables: ***
;;; mode:lisp ***
;;; comment-column:0 ***
;;; comment-start: ";;; "  ***
;;; comment-end:"***" ***
;;; End: ***
@end example

  Note that the prefix is @samp{;;; } and the suffix is @samp{ ***}.
Note also that comments in the file begin with and end with the same
strings.  Presumably the file contains code in a language which is
enough like Lisp for Lisp mode to be useful but in which comments
start and end differently.  The prefix and suffix are used in the local
variables list to make the list look like several lines of comments when
the compiler or interpreter for that language reads the file. 

  The start of the local variables list must be no more than 3000
characters from the end of the file, and must be in the last page if the
file is divided into pages.  Otherwise, Emacs will not notice it is
there.  The purpose is twofold: a stray @samp{Local Variables:}@: not in
the last page does not confuse Emacs, and Emacs never needs to search a
long file that contains no page markers and has no local variables list.

  You may be tempted to turn on Auto Fill mode with a local variable
list.  That is inappropriate.  Whether you use Auto Fill mode or not is
a matter of personal taste, not a matter of the contents of particular
files.  If you want to use Auto Fill, set up major mode hooks with your
@file{.emacs} file to turn it on (when appropriate) for you alone
(@pxref{Init File}).  Don't try to use a local variable list that would
impose your taste on everyone working with the file.

XEmacs allows you to specify local variables in the first line
of a file, in addition to specifying them in the @code{Local Variables}
section at the end of a file.

If the first line of a file contains two occurrences of @code{`-*-'},
XEmacs uses the information between them to determine what the major
mode and variable settings should be.  For example, these are all legal:

@example
	;;; -*- mode: emacs-lisp -*-
	;;; -*- mode: postscript; version-control: never -*-
	;;; -*- tags-file-name: "/foo/bar/TAGS" -*-
@end example

For historical reasons, the syntax @code{`-*- modename -*-'} is allowed
as well; for example, you can use:

@example
	;;; -*- emacs-lisp -*-
@end example

@vindex enable-local-variables
The variable @code{enable-local-variables} controls the use of local
variables lists in files you visit.  The value can be @code{t},
@code{nil}, or something else.  A value of @code{t} means local variables
lists are obeyed; @code{nil} means they are ignored; anything else means
query.

The command @code{M-x normal-mode} always obeys local variables lists
and ignores this variable.

@node Keyboard Macros
@section Keyboard Macros

@cindex keyboard macros
  A @dfn{keyboard macro} is a command defined by the user to abbreviate a
sequence of keys.  For example, if you discover that you are about to type
@kbd{C-n C-d} forty times, you can speed your work by defining a keyboard
macro to invoke @kbd{C-n C-d} and calling it with a repeat count of forty.

@c widecommands
@table @kbd
@item C-x (
Start defining a keyboard macro (@code{start-kbd-macro}).
@item C-x )
End the definition of a keyboard macro (@code{end-kbd-macro}).
@item C-x e
Execute the most recent keyboard macro (@code{call-last-kbd-macro}).
@item C-u C-x (
Re-execute last keyboard macro, then add more keys to its definition.
@item C-x q
When this point is reached during macro execution, ask for confirmation
(@code{kbd-macro-query}).
@item M-x name-last-kbd-macro
Give a command name (for the duration of the session) to the most
recently defined keyboard macro.
@item M-x insert-kbd-macro
Insert in the buffer a keyboard macro's definition, as Lisp code.
@end table

  Keyboard macros differ from other Emacs commands in that they are
written in the Emacs command language rather than in Lisp.  This makes it
easier for the novice to write them and makes them more convenient as
temporary hacks.  However, the Emacs command language is not powerful
enough as a programming language to be useful for writing anything
general or complex.  For such things, Lisp must be used.

  You define a keyboard macro by executing the commands which are its
definition.  Put differently, as you are defining a keyboard macro, the
definition is being executed for the first time.  This way, you see
what the effects of your commands are, and don't have to figure
them out in your head.  When you are finished, the keyboard macro is
defined and also has been executed once.  You can then execute the same
set of commands again by invoking the macro.

@menu
* Basic Kbd Macro::     Defining and running keyboard macros.
* Save Kbd Macro::      Giving keyboard macros names; saving them in files.
* Kbd Macro Query::     Keyboard macros that do different things each use.
@end menu

@node Basic Kbd Macro
@subsection Basic Use

@kindex C-x (
@kindex C-x )
@kindex C-x e
@findex start-kbd-macro
@findex end-kbd-macro
@findex call-last-kbd-macro
  To start defining a keyboard macro, type @kbd{C-x (}
(@code{start-kbd-macro}).  From then on, anything you type continues to be
executed, but also becomes part of the definition of the macro.  @samp{Def}
appears in the mode line to remind you of what is going on.  When you are
finished, the @kbd{C-x )} command (@code{end-kbd-macro}) terminates the
definition, without becoming part of it. 

  For example,

@example
C-x ( M-f foo C-x )
@end example

@noindent
defines a macro to move forward a word and then insert @samp{foo}.

You can give @kbd{C-x )} a repeat count as an argument, in which case it
repeats the macro that many times right after defining it, but defining
the macro counts as the first repetition (since it is executed as you
define it).  If you give @kbd{C-x )} an argument of 4, it executes the
macro immediately 3 additional times.  An argument of zero to @kbd{C-x
e} or @kbd{C-x )} means repeat the macro indefinitely (until it gets an
error or you type @kbd{C-g}).

  Once you have defined a macro, you can invoke it again with the
@kbd{C-x e} command (@code{call-last-kbd-macro}).  You can give the
command a repeat count numeric argument to execute the macro many times.

  To repeat an operation at regularly spaced places in the
text, define a macro and include as part of the macro the commands to move
to the next place you want to use it.  For example, if you want to change
each line, you should position point at the start of a line, and define a
macro to change that line and leave point at the start of the next line.
Repeating the macro will then operate on successive lines.

  After you have terminated the definition of a keyboard macro, you can add
to the end of its definition by typing @kbd{C-u C-x (}.  This is equivalent
to plain @kbd{C-x (} followed by retyping the whole definition so far.  As
a consequence it re-executes the macro as previously defined.

@node Save Kbd Macro
@subsection Naming and Saving Keyboard Macros

@findex name-last-kbd-macro
  To save a keyboard macro for longer than until you define the
next one, you must give it a name using @kbd{M-x name-last-kbd-macro}.
This reads a name as an argument using the minibuffer and defines that name
to execute the macro.  The macro name is a Lisp symbol, and defining it in
this way makes it a valid command name for calling with @kbd{M-x} or for
binding a key to with @code{global-set-key} (@pxref{Keymaps}).  If you
specify a name that has a prior definition other than another keyboard
macro, Emacs prints an error message and nothing is changed.

@findex insert-kbd-macro
  Once a macro has a command name, you can save its definition in a file.
You can then use it in another editing session.  First visit the file
you want to save the definition in.  Then use the command:

@example
M-x insert-kbd-macro @key{RET} @var{macroname} @key{RET}
@end example

@noindent
This inserts some Lisp code that, when executed later, will define the same
macro with the same definition it has now.  You need not understand Lisp
code to do this, because @code{insert-kbd-macro} writes the Lisp code for you.
Then save the file.  You can load the file with @code{load-file}
(@pxref{Lisp Libraries}).  If the file you save in is your initialization file
@file{~/.emacs} (@pxref{Init File}), then the macro will be defined each
time you run Emacs.

  If you give @code{insert-kbd-macro} a prefix argument, it creates
additional Lisp code to record the keys (if any) that you have bound to the
keyboard macro, so that the macro is reassigned the same keys when you
load the file.

@node Kbd Macro Query
@subsection Executing Macros With Variations

@kindex C-x q
@findex kbd-macro-query
  You can use @kbd{C-x q} (@code{kbd-macro-query}), to get an effect similar
to that of @code{query-replace}.  The macro asks you  each time
whether to make a change.  When you are defining the macro, type @kbd{C-x
q} at the point where you want the query to occur.  During macro
definition, the @kbd{C-x q} does nothing, but when you invoke the macro,
@kbd{C-x q} reads a character from the terminal to decide whether to
continue.

  The special answers to a @kbd{C-x q} query are @key{SPC}, @key{DEL},
@kbd{C-d}, @kbd{C-l}, and @kbd{C-r}.  Any other character terminates
execution of the keyboard macro and is then read as a command.
@key{SPC} means to continue.  @key{DEL} means to skip the remainder of
this repetition of the macro, starting again from the beginning in the
next repetition.  @kbd{C-d} means to skip the remainder of this
repetition and cancel further repetition.  @kbd{C-l} redraws the frame
and asks you again for a character to specify what to do.  @kbd{C-r} enters
a recursive editing level, in which you can perform editing that is not
part of the macro.  When you exit the recursive edit using @kbd{C-M-c},
you are asked again how to continue with the keyboard macro.  If you
type a @key{SPC} at this time, the rest of the macro definition is
executed.  It is up to you to leave point and the text in a state such
that the rest of the macro will do what you want.@refill

  @kbd{C-u C-x q}, which is @kbd{C-x q} with a numeric argument, performs a
different function.  It enters a recursive edit reading input from the
keyboard, both when you type it during the definition of the macro and
when it is executed from the macro.  During definition, the editing you do
inside the recursive edit does not become part of the macro.  During macro
execution, the recursive edit gives you a chance to do some particularized
editing.  @xref{Recursive Edit}.

@node Key Bindings
@section Customizing Key Bindings

  This section deals with the @dfn{keymaps} that define the bindings
between keys and functions, and shows how you can customize these bindings.
@cindex command
@cindex function
@cindex command name

  A command is a Lisp function whose definition provides for interactive
use.  Like every Lisp function, a command has a function name, which is
a Lisp symbol whose name usually consists of lower case letters and
hyphens.

@menu
* Keymaps::    Definition of the keymap data structure.
               Names of Emacs's standard keymaps.
* Rebinding::  How to redefine one key's meaning conveniently.
* Disabling::  Disabling a command means confirmation is required
                before it can be executed.  This is done to protect
                beginners from surprises.
@end menu

@node Keymaps
@subsection Keymaps
@cindex keymap

@cindex global keymap
@vindex global-map
  The bindings between characters and command functions are recorded in
data structures called @dfn{keymaps}.  Emacs has many of these.  One, the
@dfn{global} keymap, defines the meanings of the single-character keys that
are defined regardless of major mode.  It is the value of the variable
@code{global-map}.

@cindex local keymap
@vindex c-mode-map
@vindex lisp-mode-map
  Each major mode has another keymap, its @dfn{local keymap}, which
contains overriding definitions for the single-character keys that are
redefined in that mode.  Each buffer records which local keymap is
installed for it at any time, and the current buffer's local keymap is
the only one that directly affects command execution.  The local keymaps
for Lisp mode, C mode, and many other major modes always exist even when
not in use.  They are the values of the variables @code{lisp-mode-map},
@code{c-mode-map}, and so on.  For less frequently used major modes, the
local keymap is sometimes constructed only when the mode is used for the
first time in a session, to save space.

@cindex minibuffer
@vindex minibuffer-local-map
@vindex minibuffer-local-ns-map
@vindex minibuffer-local-completion-map
@vindex minibuffer-local-must-match-map
@vindex repeat-complex-command-map
@vindex isearch-mode-map
  There are local keymaps for the minibuffer, too; they contain various
completion and exit commands.

@itemize @bullet
@item
@code{minibuffer-local-map} is used for ordinary input (no completion).
@item
@code{minibuffer-local-ns-map} is similar, except that @key{SPC} exits
just like @key{RET}.  This is used mainly for Mocklisp compatibility.
@item
@code{minibuffer-local-completion-map} is for permissive completion.
@item
@code{minibuffer-local-must-match-map} is for strict completion and
for cautious completion.
@item
@code{repeat-complex-command-map} is for use in @kbd{C-x @key{ESC}}.
@item
@code{isearch-mode-map} contains the bindings of the special keys which
are bound in the pseudo-mode entered with @kbd{C-s} and @kbd{C-r}.
@end itemize

@vindex ctl-x-map
@vindex help-map
@vindex esc-map
  Finally, each prefix key has a keymap which defines the key sequences
that start with it.  For example, @code{ctl-x-map} is the keymap used for
characters following a @kbd{C-x}.

@itemize @bullet
@item
@code{ctl-x-map} is the variable name for the map used for characters that
follow @kbd{C-x}.
@item
@code{help-map} is used for characters that follow @kbd{C-h}.
@item
@code{esc-map} is for characters that follow @key{ESC}. All Meta
characters are actually defined by this map.
@item
@code{ctl-x-4-map} is for characters that follow @kbd{C-x 4}.
@item
@code{mode-specific-map} is for characters that follow @kbd{C-c}.
@end itemize

  The definition of a prefix key is the keymap to use for looking up
the following character.  Sometimes the definition is actually a Lisp
symbol whose function definition is the following character keymap.  The
effect is the same, but it provides a command name for the prefix key that
you can use as a description of what the prefix key is for.  Thus the
binding of @kbd{C-x} is the symbol @code{Ctl-X-Prefix}, whose function
definition is the keymap for @kbd{C-x} commands, the value of
@code{ctl-x-map}.@refill

  Prefix key definitions can appear in either the global
map or a local map.  The definitions of @kbd{C-c}, @kbd{C-x}, @kbd{C-h},
and @key{ESC} as prefix keys appear in the global map, so these prefix
keys are always available.  Major modes can locally redefine a key as a
prefix by putting a prefix key definition for it in the local
map.@refill

  A mode can also put a prefix definition of a global prefix character such
as @kbd{C-x} into its local map.  This is how major modes override the
definitions of certain keys that start with @kbd{C-x}.  This case is
special, because the local definition does not entirely replace the global
one.  When both the global and local definitions of a key are other
keymaps, the next character is looked up in both keymaps, with the local
definition overriding the global one.  The character after the
@kbd{C-x} is looked up in both the major mode's own keymap for redefined
@kbd{C-x} commands and in @code{ctl-x-map}.  If the major mode's own keymap
for @kbd{C-x} commands contains @code{nil}, the definition from the global
keymap for @kbd{C-x} commands is used.@refill

@node Rebinding
@subsection Changing Key Bindings
@cindex key rebinding, this session
@cindex rebinding keys, this session

  You can redefine an Emacs key by changing its entry in a keymap.
You can change the global keymap, in which case the change is effective in
all major modes except those that have their own overriding local
definitions for the same key.  Or you can change the current buffer's
local map, which affects all buffers using the same major mode.

@menu
* Interactive Rebinding::     Changing Key Bindings Interactively   
* Programmatic Rebinding::    Changing Key Bindings Programmatically
* Key Bindings Using Strings::Using Strings for Changing Key Bindings 
@end menu

@node Interactive Rebinding
@subsubsection Changing Key Bindings Interactively
@findex global-set-key
@findex local-set-key
@findex local-unset-key

@table @kbd
@item M-x global-set-key @key{RET} @var{key} @var{cmd} @key{RET}
Defines @var{key} globally to run @var{cmd}.
@item M-x local-set-key @key{RET} @var{keys} @var{cmd} @key{RET} 
Defines @var{key} locally (in the major mode now in effect) to run
@var{cmd}.
@item M-x local-unset-key @key{RET} @var{keys} @key{RET}
Removes the local binding of @var{key}.
@end table

@var{cmd} is a symbol naming an interactively-callable function.

When called interactively, @var{key} is the next complete key sequence
that you type.  When called as a function, @var{key} is a string, a
vector of events, or a vector of key-description lists as described in
the @code{define-key} function description.  The binding goes in
the current buffer's local map, which is shared with other buffers in
the same major mode.

The following example:

@example
M-x global-set-key @key{RET} C-f next-line @key{RET}
@end example

@noindent
redefines @kbd{C-f} to move down a line.  The fact that @var{cmd} is
read second makes it serve as a kind of confirmation for @var{key}.

  These functions offer no way to specify a particular prefix keymap as
the one to redefine in, but that is not necessary, as you can include
prefixes in @var{key}.  @var{key} is read by reading characters one by
one until they amount to a complete key (that is, not a prefix key).
Thus, if you type @kbd{C-f} for @var{key}, Emacs enters
the minibuffer immediately to read @var{cmd}.  But if you type
@kbd{C-x}, another character is read; if that character is @kbd{4},
another character is read, and so on.  For example,@refill

@example
M-x global-set-key @key{RET} C-x 4 $ spell-other-window @key{RET}
@end example

@noindent
redefines @kbd{C-x 4 $} to run the (fictitious) command
@code{spell-other-window}.

@findex define-key
@findex substitute-key-definition
  The most general way to modify a keymap is the function
@code{define-key}, used in Lisp code (such as your @file{.emacs} file).
@code{define-key} takes three arguments: the keymap, the key to modify
in it, and the new definition.  @xref{Init File}, for an example.
@code{substitute-key-definition} is used similarly; it takes three
arguments, an old definition, a new definition, and a keymap, and
redefines in that keymap all keys that were previously defined with the
old definition to have the new definition instead.

@node Programmatic Rebinding
@subsubsection Changing Key Bindings Programmatically

  You can use the functions @code{global-set-key} and @code{define-key}
to rebind keys under program control.

@findex define-key
@findex global-set-key

@table @kbd
@item  @code{(global-set-key @var{keys} @var{cmd})}
Defines @var{keys} globally to run @var{cmd}.
@item @code{(define-key @var{keymap} @var{keys} @var{def})}
Defines @var{keys} to run @var{def} in the keymap @var{keymap}.
@end table
 
@var{keymap} is a keymap object.

@var{keys} is the sequence of keystrokes to bind.

@var{def} is anything that can be a key's definition:

@itemize @bullet
@item
@code{nil}, meaning key is undefined in this keymap
@item
A command, that is, a Lisp function suitable for interactive calling
@item
A string or key sequence vector, which is treated as a keyboard macro
@item
A keymap to define a prefix key
@item
A symbol so that when the key is looked up, the symbol stands for its
function definition, which should at that time be one of the above,
or another symbol whose function definition is used, and so on
@item
A cons, @code{(string . defn)}, meaning that @var{defn} is the definition
(@var{defn} should be a valid definition in its own right)
@item
A cons, @code{(keymap . char)}, meaning use the definition of
@var{char} in map @var{keymap}
@end itemize

For backward compatibility, XEmacs allows you to specify key
sequences as strings.  However, the preferred method is to use the
representations of key sequences as vectors of keystrokes.
@xref{Keystrokes}, for more information about the rules for constructing
key sequences.

Emacs allows you to abbreviate representations for key sequences in 
most places where there is no ambiguity.
Here are some rules for abbreviation:

@itemize @bullet
@item
The keysym by itself is equivalent to a list of just that keysym, i.e.,
@code{f1} is equivalent to @code{(f1)}.
@item
A keystroke by itself is equivalent to a vector containing just that
keystroke, i.e.,  @code{(control a)} is equivalent to @code{[(control a)]}.
@item
You can use ASCII codes for keysyms that have them. i.e.,
@code{65} is equivalent to @code{A}. (This is not so much an
abbreviation as an alternate representation.)
@end itemize

Here are some examples of programmatically binding keys:

@example

;;;  Bind @code{my-command} to @key{f1}
(global-set-key 'f1 'my-command)		

;;;  Bind @code{my-command} to @kbd{Shift-f1}
(global-set-key '(shift f1) 'my-command)

;;; Bind @code{my-command} to @kbd{C-c Shift-f1}
(global-set-key '[(control c) (shift f1)] 'my-command)	

;;; Bind @code{my-command} to the middle mouse button.
(global-set-key 'button2 'my-command)

;;; Bind @code{my-command} to @kbd{@key{META} @key{CTL} @key{Right Mouse Button}}
;;; in the keymap that is in force when you are running @code{dired}.
(define-key dired-mode-map '(meta control button3) 'my-command)

@end example

@comment ;; note that these next four lines are not synonymous:
@comment ;;
@comment (global-set-key '(meta control delete) 'my-command)
@comment (global-set-key '(meta control backspace) 'my-command)
@comment (global-set-key '(meta control h) 'my-command)
@comment (global-set-key '(meta control H) 'my-command)
@comment 
@comment ;; note that this binds two key sequences: ``control-j'' and ``linefeed''.
@comment ;;
@comment (global-set-key "\^J" 'my-command)

@node Key Bindings Using Strings
@subsubsection Using Strings for Changing Key Bindings 

  For backward compatibility, you can still use strings to represent
key sequences.  Thus you can use commands like the following:

@example
;;; Bind @code{end-of-line} to @kbd{C-f}
(global-set-key "\C-f" 'end-of-line)
@end example

Note, however, that in some cases you may be binding more than one
key sequence by using a single command.  This situation can 
arise because in ASCII, @kbd{C-i} and @key{TAB} have
the same representation.  Therefore, when Emacs sees:

@example
(global-set-key "\C-i" 'end-of-line)
@end example

it is unclear whether the user intended to bind @kbd{C-i} or @key{TAB}.
The solution XEmacs adopts is to bind both of these key
sequences.

@cindex redefining keys
After binding a command to two key sequences with a form like:

@example
	(define-key global-map "\^X\^I" 'command-1)
@end example

it is possible to redefine only one of those sequences like so:

@example
	(define-key global-map [(control x) (control i)] 'command-2)
	(define-key global-map [(control x) tab] 'command-3)
@end example

This applies only when running under a window system.  If you are
talking to Emacs through an ASCII-only channel, you do not get any of
these features.

Here is a table of pairs of key sequences that behave in a
similar fashion:

@example
        control h      backspace           
        control l      clear
        control i      tab 
        control m      return              
        control j      linefeed 
        control [      escape
        control @@      control space
@end example

@node Disabling
@subsection Disabling Commands
@cindex disabled command

  Disabling a command marks it as requiring confirmation before it
can be executed.  The purpose of disabling a command is to prevent
beginning users from executing it by accident and being confused.

  The direct mechanism for disabling a command is to have a non-@code{nil}
@code{disabled} property on the Lisp symbol for the command.  These
properties are normally set by the user's @file{.emacs} file with
Lisp expressions such as:

@example
(put 'delete-region 'disabled t)
@end example

  If the value of the @code{disabled} property is a string, that string
is included in the message printed when the command is used:

@example
(put 'delete-region 'disabled
     "Text deleted this way cannot be yanked back!\n")
@end example

@findex disable-command
@findex enable-command
  You can disable a command either by editing the @file{.emacs} file
directly or with the command @kbd{M-x disable-command}, which edits the
@file{.emacs} file for you.  @xref{Init File}.

  When you attempt to invoke a disabled command interactively in Emacs,
a window is displayed containing the command's name, its
documentation, and some instructions on what to do next; then
Emacs asks for input saying whether to execute the command as requested,
enable it and execute, or cancel it.  If you decide to enable the
command, you are asked whether to do this permanently or just for the
current session.  Enabling permanently works by automatically editing
your @file{.emacs} file.  You can use @kbd{M-x enable-command} at any
time to enable any command permanently.

  Whether a command is disabled is independent of what key is used to
invoke it; it also applies if the command is invoked using @kbd{M-x}.
Disabling a command has no effect on calling it as a function from Lisp
programs.

@node Syntax
@section The Syntax Table
@cindex syntax table

  All the Emacs commands which parse words or balance parentheses are
controlled by the @dfn{syntax table}.  The syntax table specifies which
characters are opening delimiters, which are parts of words, which are
string quotes, and so on.  Actually, each major mode has its own syntax
table (though sometimes related major modes use the same one) which it
installs in each buffer that uses that major mode.  The syntax table
installed in the current buffer is the one that all commands use, so we
call it ``the'' syntax table.  A syntax table is a Lisp object, a vector of
length 256 whose elements are numbers.

@menu
* Entry: Syntax Entry.    What the syntax table records for each character.
* Change: Syntax Change.  How to change the information.
@end menu

@node Syntax Entry
@subsection Information About Each Character

  The syntax table entry for a character is a number that encodes six
pieces of information:

@itemize @bullet
@item
The syntactic class of the character, represented as a small integer
@item
The matching delimiter, for delimiter characters only
(the matching delimiter of @samp{(} is @samp{)}, and vice versa)
@item
A flag saying whether the character is the first character of a
two-character comment starting sequence
@item
A flag saying whether the character is the second character of a
two-character comment starting sequence
@item
A flag saying whether the character is the first character of a
two-character comment ending sequence
@item
A flag saying whether the character is the second character of a
two-character comment ending sequence
@end itemize

  The syntactic classes are stored internally as small integers, but are
usually described to or by the user with characters.  For example, @samp{(}
is used to specify the syntactic class of opening delimiters.  Here is a
table of syntactic classes, with the characters that specify them.

@table @samp
@item @w{ }
The class of whitespace characters.
@item w
The class of word-constituent characters.
@item _
The class of characters that are part of symbol names but not words.
This class is represented by @samp{_} because the character @samp{_}
has this class in both C and Lisp.
@item .
The class of punctuation characters that do not fit into any other
special class.
@item (
The class of opening delimiters.
@item )
The class of closing delimiters.
@item '
The class of expression-adhering characters.  These characters are
part of a symbol if found within or adjacent to one, and are part
of a following expression if immediately preceding one, but are like
whitespace if surrounded by whitespace.
@item "
The class of string-quote characters.  They match each other in pairs,
and the characters within the pair all lose their syntactic
significance except for the @samp{\} and @samp{/} classes of escape
characters, which can be used to include a string-quote inside the
string.
@item $
The class of self-matching delimiters.  This is intended for @TeX{}'s
@samp{$}, which is used both to enter and leave math mode.  Thus,
a pair of matching @samp{$} characters surround each piece of math mode
@TeX{} input.  A pair of adjacent @samp{$} characters act like a single
one for purposes of matching.

@item /
The class of escape characters that always just deny the following
character its special syntactic significance.  The character after one
of these escapes is always treated as alphabetic.
@item \
The class of C-style escape characters.  In practice, these are
treated just like @samp{/}-class characters, because the extra
possibilities for C escapes (such as being followed by digits) have no
effect on where the containing expression ends.
@item <
The class of comment-starting characters.  Only single-character
comment starters (such as @samp{;} in Lisp mode) are represented this
way.
@item >
The class of comment-ending characters.  Newline has this syntax in
Lisp mode.
@end table

@vindex parse-sexp-ignore-comments
  The characters flagged as part of two-character comment delimiters can
have other syntactic functions most of the time.  For example, @samp{/} and
@samp{*} in C code, when found separately, have nothing to do with
comments.  The comment-delimiter significance overrides when the pair of
characters occur together in the proper order.  Only the list and sexp
commands use the syntax table to find comments; the commands specifically
for comments have other variables that tell them where to find comments.
Moreover, the list and sexp commands notice comments only if
@code{parse-sexp-ignore-comments} is non-@code{nil}.  This variable is set
to @code{nil} in modes where comment-terminator sequences are liable to
appear where there is no comment, for example, in Lisp mode where the
comment terminator is a newline but not every newline ends a comment.

@node Syntax Change
@subsection Altering Syntax Information

  It is possible to alter a character's syntax table entry by storing a new
number in the appropriate element of the syntax table, but it would be hard
to determine what number to use.  Emacs therefore provides a command that
allows you to specify the syntactic properties of a character in a
convenient way.

@findex modify-syntax-entry
  @kbd{M-x modify-syntax-entry} is the command to change a character's
syntax.  It can be used interactively and is also used by major
modes to initialize their own syntax tables.  Its first argument is the
character to change.  The second argument is a string that specifies the
new syntax.  When called from Lisp code, there is a third, optional
argument, which specifies the syntax table in which to make the change.  If
not supplied, or if this command is called interactively, the third
argument defaults to the current buffer's syntax table.

@enumerate
@item
The first character in the string specifies the syntactic class.  It
is one of the characters in the previous table (@pxref{Syntax Entry}).

@item
The second character is the matching delimiter.  For a character that
is not an opening or closing delimiter, this should be a space, and may
be omitted if no following characters are needed.

@item
The remaining characters are flags.  The flag characters allowed are:

@table @samp
@item 1
Flag this character as the first of a two-character comment starting sequence.
@item 2
Flag this character as the second of a two-character comment starting sequence.
@item 3
Flag this character as the first of a two-character comment ending sequence.
@item 4
Flag this character as the second of a two-character comment ending sequence.
@end table
@end enumerate

@kindex C-h s
@findex describe-syntax
  Use @kbd{C-h s} (@code{describe-syntax}) to display a description of
the contents of the current syntax table.  The description of each
character includes both the string you have to pass to
@code{modify-syntax-entry} to set up that character's current syntax,
and some English to explain that string if necessary.

@node Init File
@section The Init File, .emacs
@cindex init file
@cindex Emacs initialization file
@cindex key rebinding, permanent
@cindex rebinding keys, permanently

  When you start Emacs, it normally loads the file @file{.emacs} in your
home directory.  This file, if it exists, should contain Lisp code.  It
is called your initialization file or @dfn{init file}.  Use the command
line switches @samp{-q} and @samp{-u} to tell Emacs whether to load an
init file (@pxref{Entering Emacs}).

@vindex init-file-user
When the @file{.emacs} file is read, the variable @code{init-file-user}
says which user's init file it is.  The value may be the null string or a
string containing a user's name.  If the value is a null string, it means
that the init file was taken from the user that originally logged in.

In all cases, @code{(concat "~" init-file-user "/")} evaluates to the
directory name of the directory where the @file{.emacs} file was looked
for.

  At some sites there is a @dfn{default init file}, which is the
library named @file{default.el}, found via the standard search path for
libraries.  The Emacs distribution contains no such library; your site
may create one for local customizations.  If this library exists, it is
loaded whenever you start Emacs.  But your init file, if any, is loaded
first; if it sets @code{inhibit-default-init} non-@code{nil}, then
@file{default} is not loaded.

  If you have a large amount of code in your @file{.emacs} file, you
should move it into another file named @file{@var{something}.el},
byte-compile it (@pxref{Lisp Libraries}), and load that file from your
@file{.emacs} file using @code{load}.

@menu
* Init Syntax::     Syntax of constants in Emacs Lisp.
* Init Examples::   How to do some things with an init file.
* Terminal Init::   Each terminal type can have an init file.
@end menu

@node Init Syntax
@subsection Init File Syntax

  The @file{.emacs} file contains one or more Lisp function call
expressions.  Each consists of a function name followed by
arguments, all surrounded by parentheses.  For example, @code{(setq
fill-column 60)} represents a call to the function @code{setq} which is
used to set the variable @code{fill-column} (@pxref{Filling}) to 60.

  The second argument to @code{setq} is an expression for the new value
of the variable.  This can be a constant, a variable, or a function call
expression.  In @file{.emacs}, constants are used most of the time.
They can be:

@table @asis
@item Numbers
Integers are written in decimal, with an optional initial minus sign.

If a sequence of digits is followed by a period and another sequence
of digits, it is interpreted as a floating point number.

@item Strings
Lisp string syntax is the same as C string syntax with a few extra
features.  Use a double-quote character to begin and end a string constant.

Newlines and special characters may be present literally in strings.  They
can also be represented as backslash sequences: @samp{\n} for newline,
@samp{\b} for backspace, @samp{\r} for return, @samp{\t} for tab,
@samp{\f} for formfeed (control-l), @samp{\e} for escape, @samp{\\} for a
backslash, @samp{\"} for a double-quote, or @samp{\@var{ooo}} for the
character whose octal code is @var{ooo}.  Backslash and double-quote are
the only characters for which backslash sequences are mandatory.

You can use @samp{\C-} as a prefix for a control character, as in
@samp{\C-s} for ASCII Control-S, and @samp{\M-} as a prefix for
a Meta character, as in @samp{\M-a} for Meta-A or @samp{\M-\C-a} for
Control-Meta-A.@refill

@item Characters
Lisp character constant syntax consists of a @samp{?} followed by
either a character or an escape sequence starting with @samp{\}.
Examples: @code{?x}, @code{?\n}, @code{?\"}, @code{?\)}.  Note that
strings and characters are not interchangeable in Lisp; some contexts
require one and some contexts require the other.

@item True
@code{t} stands for `true'.

@item False
@code{nil} stands for `false'.

@item Other Lisp objects
Write a single-quote (') followed by the Lisp object you want.
@end table

@node Init Examples
@subsection Init File Examples

  Here are some examples of doing certain commonly desired things with
Lisp expressions:

@itemize @bullet
@item
Make @key{TAB} in C mode just insert a tab if point is in the middle of a
line.

@example
(setq c-tab-always-indent nil)
@end example

Here we have a variable whose value is normally @code{t} for `true'
and the alternative is @code{nil} for `false'.

@item
Make searches case sensitive by default (in all buffers that do not
override this).

@example
(setq-default case-fold-search nil)
@end example

This sets the default value, which is effective in all buffers that do
not have local values for the variable.  Setting @code{case-fold-search}
with @code{setq} affects only the current buffer's local value, which
is probably not what you want to do in an init file.

@item
Make Text mode the default mode for new buffers.

@example
(setq default-major-mode 'text-mode)
@end example

Note that @code{text-mode} is used because it is the command for entering
the mode we want.  A single-quote is written before it to make a symbol
constant; otherwise, @code{text-mode} would be treated as a variable name.

@item
Turn on Auto Fill mode automatically in Text mode and related modes.

@example
(setq text-mode-hook
  '(lambda () (auto-fill-mode 1)))
@end example

Here we have a variable whose value should be a Lisp function.  The
function we supply is a list starting with @code{lambda}, and a single
quote is written in front of it to make it (for the purpose of this
@code{setq}) a list constant rather than an expression.  Lisp functions
are not explained here; for mode hooks it is enough to know that
@code{(auto-fill-mode 1)} is an expression that will be executed when
Text mode is entered.  You could replace it with any other expression
that you like, or with several expressions in a row.

@example
(setq text-mode-hook 'turn-on-auto-fill)
@end example

This is another way to accomplish the same result.
@code{turn-on-auto-fill} is a symbol whose function definition is
@code{(lambda () (auto-fill-mode 1))}.

@item
Load the installed Lisp library named @file{foo} (actually a file
@file{foo.elc} or @file{foo.el} in a standard Emacs directory).

@example
(load "foo")
@end example

When the argument to @code{load} is a relative pathname, not starting
with @samp{/} or @samp{~}, @code{load} searches the directories in
@code{load-path} (@pxref{Loading}).

@item
Load the compiled Lisp file @file{foo.elc} from your home directory.

@example
(load "~/foo.elc")
@end example

Here an absolute file name is used, so no searching is done.

@item
Rebind the key @kbd{C-x l} to run the function @code{make-symbolic-link}.

@example
(global-set-key "\C-xl" 'make-symbolic-link)
@end example

or

@example
(define-key global-map "\C-xl" 'make-symbolic-link)
@end example

Note once again the single-quote used to refer to the symbol
@code{make-symbolic-link} instead of its value as a variable.

@item
Do the same thing for C mode only.

@example
(define-key c-mode-map "\C-xl" 'make-symbolic-link)
@end example

@item
Bind the function key @key{F1} to a command in C mode.
Note that the names of function keys must be lower case.

@example
(define-key c-mode-map 'f1 'make-symbolic-link)
@end example

@item
Bind the shifted version of @key{F1} to a command.

@example
(define-key c-mode-map '(shift f1) 'make-symbolic-link)
@end example

@item
Redefine all keys which now run @code{next-line} in Fundamental mode
to run @code{forward-line} instead.

@example
(substitute-key-definition 'next-line 'forward-line
                           global-map)
@end example

@item
Make @kbd{C-x C-v} undefined.

@example
(global-unset-key "\C-x\C-v")
@end example

One reason to undefine a key is so that you can make it a prefix.
Simply defining @kbd{C-x C-v @var{anything}} would make @kbd{C-x C-v}
a prefix, but @kbd{C-x C-v} must be freed of any non-prefix definition
first.

@item
Make @samp{$} have the syntax of punctuation in Text mode.
Note the use of a character constant for @samp{$}.

@example
(modify-syntax-entry ?\$ "." text-mode-syntax-table)
@end example

@item
Enable the use of the command @code{eval-expression} without confirmation.

@example
(put 'eval-expression 'disabled nil)
@end example
@end itemize

@node Terminal Init
@subsection Terminal-Specific Initialization

  Each terminal type can have a Lisp library to be loaded into Emacs when
it is run on that type of terminal.  For a terminal type named
@var{termtype}, the library is called @file{term/@var{termtype}} and it is
found by searching the directories @code{load-path} as usual and trying the
suffixes @samp{.elc} and @samp{.el}.  Normally it appears in the
subdirectory @file{term} of the directory where most Emacs libraries are
kept.@refill

  The usual purpose of the terminal-specific library is to define the
escape sequences used by the terminal's function keys using the library
@file{keypad.el}.  See the file
@file{term/vt100.el} for an example of how this is done.@refill

  When the terminal type contains a hyphen, only the part of the name
before the first hyphen is significant in choosing the library name.
Thus, terminal types @samp{aaa-48} and @samp{aaa-30-rv} both use
the library @file{term/aaa}.  The code in the library can use
@code{(getenv "TERM")} to find the full terminal type name.@refill

@vindex term-file-prefix
  The library's name is constructed by concatenating the value of the
variable @code{term-file-prefix} and the terminal type.  Your @file{.emacs}
file can prevent the loading of the terminal-specific library by setting
@code{term-file-prefix} to @code{nil}.

@vindex term-setup-hook
  The value of the variable @code{term-setup-hook}, if not @code{nil}, is
called as a function of no arguments at the end of Emacs initialization,
after both your @file{.emacs} file and any terminal-specific library have
been read.  You can set the value in the @file{.emacs} file to override
part of any of the terminal-specific libraries and to define
initializations for terminals that do not have a library.@refill

@node Audible Bell
@section Changing the Bell Sound
@cindex audible bell, changing
@cindex bell, changing
@vindex sound-alist
@findex load-default-sounds
@findex play-sound

You can now change how the audible bell sounds using the variable
@code{sound-alist}.

@code{sound-alist}'s value is an list associating symbols with, among
other things, strings of audio-data.  When @code{ding} is called with
one of the symbols, the associated sound data is played instead of the
standard beep.  This only works if you are logged in on the console of a
machine with audio hardware. To listen to a sound of the provided type,
call the function @code{play-sound} with the argument @var{sound}. You
can also set the volume of the sound with the optional argument 
@var{volume}.@refill
@cindex ding

Each element of @code{sound-alist} is a list describing a sound.
The first element of the list is the name of the sound being defined.
Subsequent elements of the list are alternating keyword/value pairs:

@table @code
@item sound
A string of raw sound data, or the name of another sound to play.   
The symbol @code{t} here means use the default X beep.

@item volume
An integer from 0-100, defaulting to @code{bell-volume}.

@item pitch
If using the default X beep, the pitch (Hz) to generate.

@item duration
If using the default X beep, the duration (milliseconds).
@end table

For compatibility, elements of `sound-alist' may also be of the form:

@example
( @var{sound-name} . @var{<sound>} )
( @var{sound-name} @var{<volume>} @var{<sound>} )
@end example

You should probably add things to this list by calling the function
@code{load-sound-file}.

Note that you can only play audio data if running on the console screen
of a machine with audio hardware which emacs understands, which at this
time means a Sun SparcStation, SGI, or HP9000s700.

Also note that the pitch, duration, and volume options are available
everywhere, but most X servers ignore the `pitch' option.

@vindex bell-volume
The variable @code{bell-volume} should be an integer from 0 to 100,
with 100 being loudest, which controls how loud the sounds emacs makes
should be.  Elements of the @code{sound-alist} may override this value.
This variable applies to the standard X bell sound as well as sound files.

If the symbol @code{t} is in place of a sound-string, Emacs uses the
default X beep.  This allows you to define beep-types of 
different volumes even when not running on the console.

@findex load-sound-file
You can add things to this list by calling the function
@code{load-sound-file}, which reads in an audio-file and adds its data to
the sound-alist. You can specify the sound with the @var{sound-name}
argument and the file into which the sounds are loaded with the
@var{filename} argument. The optional @var{volume} argument sets the
volume.

@code{load-sound-file (@var{filename sound-name} &optional @var{volume})}

To load and install some sound files as beep-types, use the function
@code{load-default-sounds} (note that this only works if you are on
display 0 of a machine with audio hardware).

The following beep-types are used by Emacs itself. Other Lisp
packages may use other beep types, but these are the ones that the C
kernel of Emacs uses.

@table @code
@item auto-save-error
An auto-save does not succeed

@item command-error
The Emacs command loop catches an error

@item undefined-key
You type a key that is undefined

@item undefined-click	
You use an undefined mouse-click combination

@item no-completion	
Completion was not possible

@item y-or-n-p		
You type something other than the required @code{y} or @code{n}

@item yes-or-no-p  	
You type something other than @code{yes} or @code{no}
@end table

@comment  node-name,  next,  previous,  up
@node Faces
@section Faces

XEmacs has objects called extents and faces.  An @dfn{extent}
is a region of text and a @dfn{face} is a collection of textual
attributes, such as fonts and colors.  Every extent is displayed in some
face; therefore, changing the properties of a face immediately updates the
display of all associated extents.  Faces can be frame-local: you can
have a region of text that displays with completely different
attributes when its buffer is viewed from a different X window.

The display attributes of faces may be specified either in Lisp or through
the X resource manager.

@subsection Customizing Faces

You can change the face of an extent with the functions in
this section.  All the functions prompt for a @var{face} as an
argument; use completion for a list of possible values.

@table @kbd
@item M-x invert-face
Swap the foreground and background colors of the given @var{face}.
@item M-x make-face-bold
Make the font of the given @var{face} bold.  When called from a
program, returns @code{nil} if this is not possible.
@item M-x make-face-bold-italic
Make the font of the given @var{face} bold italic.  
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-italic
Make the font of the given @var{face} italic.  
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-unbold
Make the font of the given @var{face} non-bold.  
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-unitalic
Make the font of the given @var{face} non-italic.
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-larger
Make the font of the given @var{face} a little larger.
When called from a program, returns @code{nil} if not possible.
@item M-x make-face-smaller
Make the font of the given @var{face} a little smaller.
When called from a program, returns @code{nil} if not possible.
@item M-x set-face-background 
Change the background color of the given @var{face}.
@item M-x set-face-background-pixmap
Change the background pixmap of the given @var{face}.
@item M-x set-face-font 
Change the font of the given @var{face}.
@item M-x set-face-foreground
Change the foreground color of the given @var{face}.
@item M-x set-face-underline-p
Change whether the given @var{face} is underlined.
@end table

@findex make-face-bold
@findex make-face-bold-italic
@findex make-face-italic
@findex make-face-unbold
@findex make-face-unitalic
@findex make-face-larger
@findex make-face-smaller

@findex invert-face
You can exchange the foreground and background color of the selected
@var{face} with the function @code{invert-face}. If the face does not
specify both foreground and background, then its foreground and
background are set to the background and foreground of the default face.
When calling this from a program, you can supply the optional argument 
@var{frame} to specify which frame is affected; otherwise, all frames
are affected.

@findex set-face-background
You can set the background color of the specified @var{face} with the
function @code{set-face-background}.  The argument @code{color} should
be a string, the name of a color.  When called from a program, if the
optional @var{frame} argument is provided, the face is changed only 
in that frame; otherwise, it is changed in all frames.

@findex set-face-background-pixmap
You can set the background pixmap of the specified @var{face} with the
function @code{set-face-background-pixmap}.  The pixmap argument
@var{name} should be a string, the name of a file of pixmap data.  The
directories listed in the @code{x-bitmap-file-path} variable are
searched.  The bitmap may also be a list of the form @code{(@var{width
height data})}, where @var{width} and @var{height} are the size in
pixels, and @var{data} is a string containing the raw bits of the
bitmap.  If the optional @var{frame} argument is provided, the face is
changed only in that frame; otherwise, it is changed in all frames.

The variable @code{x-bitmap-file-path} takes as a value a list of the
directories in which X bitmap files may be found.  If the value is
@code{nil}, the list is initialized from the @code{*bitmapFilePath}
resource.

If the environment variable @b{XBMLANGPATH} is set, then it is consulted
before the @code{x-bitmap-file-path} variable.

@findex set-face-font
You can set the font of the specified @var{face} with the function
@code{set-face-font}.  The @var{font} argument should be a string, the
name of a font.  When called from a program, if the
optional @var{frame} argument is provided, the face is changed only 
in that frame; otherwise, it is changed in all frames.

@findex set-face-foreground 
You can set the foreground color of the specified @var{face} with the
function @code{set-face-foreground}.  The argument @var{color} should be
a string, the name of a color.  If the optional @var{frame} argument is
provided, the face is changed only in that frame; otherwise, it is
changed in all frames.

@findex set-face-underline-p
You can set underline the specified @var{face} with the function
@code{set-face-underline-p}. The argument @var{underline-p} can be used
to make underlining an attribute of the face or not. If the optional
@var{frame} argument is provided, the face is changed only in that
frame; otherwise, it is changed in all frames.

@node X Resources
@section X Resources
@cindex X resources
@findex x-create-frame

The Emacs resources are generally set per-frame. Each Emacs frame can have 
its own name or the same name as another, depending on the name passed to the 
@code{make-frame} function.

You can specify resources for all frames with the syntax:

@example
Emacs*parameter: value
@end example
@noindent

or

@example
Emacs*EmacsFrame.parameter:value
@end example
@noindent

You can specify resources for a particular frame with the syntax:

@example
Emacs*FRAME-NAME.parameter: value
@end example
@noindent

@menu
* Geometry Resources::     Controlling the size and position of frames.
* Iconic Resources::	   Controlling whether frames come up iconic.
* Resource List::	   List of resources settable on a frame or device.
* Face Resources::	   Controlling faces using resources.
* Widgets::		   The widget hierarchy for XEmacs.
* Menubar Resources::	   Specifying resources for the menubar.
@end menu

@node Geometry Resources
@subsection Geometry Resources

To make the default size of all Emacs frames be 80 columns by 55 lines,
do this:

@example
Emacs*EmacsFrame.geometry: 80x55
@end example
@noindent

To set the geometry of a particular frame named @samp{fred}, do this:

@example
Emacs*fred.geometry: 80x55
@end example
@noindent

Important! Do not use the following syntax:

@example
Emacs*geometry: 80x55
@end example
@noindent

You should never use @code{*geometry} with any X application. It does
not say "make the geometry of Emacs be 80 columns by 55 lines."  It
really says, "make Emacs and all subwindows thereof be 80x55 in whatever
units they care to measure in."  In particular, that is both telling the
Emacs text pane to be 80x55 in characters, and telling the menubar pane
to be 80x55 pixels, which is surely not what you want.

As a special case, this geometry specification also works (and sets the
default size of all Emacs frames to 80 columns by 55 lines):

@example
Emacs.geometry: 80x55
@end example
@noindent

since that is the syntax used with most other applications (since most
other applications have only one top-level window, unlike Emacs).  In
general, however, the top-level shell (the unmapped ApplicationShell
widget named @samp{Emacs} that is the parent of the shell widgets that
actually manage the individual frames) does not have any interesting
resources on it, and you should set the resources on the frames instead.

The @code{-geometry} command-line argument sets only the geometry of the
initial frame created by Emacs.

A more complete explanation of geometry-handling is

@itemize @bullet
@item
The @code{-geometry} command-line option sets the @code{Emacs.geometry}
resource, that is, the geometry of the ApplicationShell.

@item
For the first frame created, the size of the frame is taken from the
ApplicationShell if it is specified, otherwise from the geometry of the
frame.

@item
For subsequent frames, the order is reversed: First the frame, and then
the ApplicationShell.

@item
For the first frame created, the position of the frame is taken from the
ApplicationShell (@code{Emacs.geometry}) if it is specified, otherwise
from the geometry of the frame.

@item
For subsequent frames, the position is taken only from the frame, and 
never from the ApplicationShell.
@end itemize

This is rather complicated, but it does seem to provide the most
intuitive behavior with respect to the default sizes and positions of
frames created in various ways.

@node Iconic Resources
@subsection Iconic Resources

Analogous to @code{-geometry}, the @code{-iconic} command-line option
sets the iconic flag of the ApplicationShell (@code{Emacs.iconic}) and
always applies to the first frame created regardless of its name.
However, it is possible to set the iconic flag on particular frames (by
name) by using the @code{Emacs*FRAME-NAME.iconic} resource.

@node Resource List
@subsection Resource List

Emacs frames accept the following resources:

@table @asis
@item @code{geometry} (class @code{Geometry}): string
Initial geometry for the frame.  @xref{Geometry Resources} for a
complete discussion of how this works.

@item @code{iconic} (class @code{Iconic}): boolean
Whether this frame should appear in the iconified state.

@item @code{internalBorderWidth} (class @code{InternalBorderWidth}): int
How many blank pixels to leave between the text and the edge of the 
window.

@item @code{interline} (class @code{Interline}): int
How many pixels to leave between each line (may not be implemented).

@item @code{menubar} (class @code{Menubar}): boolean
Whether newly-created frames should initially have a menubar.  Set to
true by default.

@item @code{initiallyUnmapped} (class @code{InitiallyUnmapped}): boolean
Whether XEmacs should leave the initial frame unmapped when it starts
up.  This is useful if you are starting XEmacs as a server (e.g. in
conjunction with gnuserv or the external client widget).  You can also
control this with the @code{-unmapped} command-line option.

@item @code{barCursor} (class @code{BarColor}): boolean
Whether the cursor should be displayed as a bar, or the traditional box.

@item @code{cursorColor} (class @code{CursorColor}): color-name
The color of the text cursor.

@item @code{scrollBarWidth} (class @code{ScrollBarWidth}): integer
How wide the vertical scrollbars should be, in pixels; 0 means no
vertical scrollbars.  You can also use a resource specification of the
form @code{*scrollbar.width}, or the usual toolkit scrollbar resources:
@code{*XmScrollBar.width} (Motif), @code{*XlwScrollBar.width} (Lucid),
or @code{*Scrollbar.thickness} (Athena).  We don't recommend that you
use the toolkit resources, though, because they're dependent on how
exactly your particular build of XEmacs was configured.

@item @code{scrollBarHeight} (class @code{ScrollBarHeight}): integer
How high the horizontal scrollbars should be, in pixels; 0 means no
horizontal scrollbars.  You can also use a resource specification of the
form @code{*scrollbar.height}, or the usual toolkit scrollbar resources:
@code{*XmScrollBar.height} (Motif), @code{*XlwScrollBar.height} (Lucid),
or @code{*Scrollbar.thickness} (Athena).  We don't recommend that you use
the toolkit resources, though, because they're dependent on how exactly
your particular build of XEmacs was configured.

@item @code{scrollBarPlacement} (class @code{ScrollBarPlacement}): string
Where the horizontal and vertical scrollbars should be positioned.  This
should be one of the four strings @samp{BOTTOM_LEFT},
@samp{BOTTOM_RIGHT}, @samp{TOP_LEFT}, and @samp{TOP_RIGHT}.  Default is
@samp{BOTTOM_RIGHT} for the Motif and Lucid scrollbars and
@samp{BOTTOM_LEFT} for the Athena scrollbars.

@item @code{topToolBarHeight} (class @code{TopToolBarHeight}): integer
@itemx @code{bottomToolBarHeight} (class @code{BottomToolBarHeight}): integer
@itemx @code{leftToolBarWidth} (class @code{LeftToolBarWidth}): integer
@itemx @code{rightToolBarWidth} (class @code{RightToolBarWidth}): integer
Height and width of the four possible toolbars.

@item @code{topToolBarShadowColor} (class @code{TopToolBarShadowColor}): color-name
@itemx @code{bottomToolBarShadowColor} (class @code{BottomToolBarShadowColor}): color-name
Color of the top and bottom shadows for the toolbars.  NOTE: These resources
do @emph{not} have anything to do with the top and bottom toolbars (i.e. the
toolbars at the top and bottom of the frame)!  Rather, they affect the top
and bottom shadows around the edges of all four kinds of toolbars.

@item @code{topToolBarShadowPixmap} (class @code{TopToolBarShadowPixmap}): pixmap-name
@itemx @code{bottomToolBarShadowPixmap} (class @code{BottomToolBarShadowPixmap}): pixmap-name
Pixmap of the top and bottom shadows for the toolbars.  If set, these
resources override the corresponding color resources. NOTE: These
resources do @emph{not} have anything to do with the top and bottom
toolbars (i.e. the toolbars at the top and bottom of the frame)!
Rather, they affect the top and bottom shadows around the edges of all
four kinds of toolbars.

@item @code{toolBarShadowThickness} (class @code{ToolBarShadowThickness}): integer
Thickness of the shadows around the toolbars, in pixels.

@item @code{visualBell} (class @code{VisualBell}): boolean
Whether XEmacs should flash the screen rather than making an audible beep.

@item @code{bellVolume} (class @code{BellVolume}): integer
Volume of the audible beep.

@item @code{useBackingStore} (class @code{UseBackingStore}): boolean
Whether XEmacs should set the backing-store attribute of the X windows
it creates.  This increases the memory usage of the X server but decreases
the amount of X traffic necessary to update the screen, and is useful
when the connection to the X server goes over a low-bandwidth line
such as a modem connection.
@end table

Emacs devices accept the following resources:

@table @asis
@item @code{textPointer} (class @code{Cursor}): cursor-name
The cursor to use when the mouse is over text.  This resource is used to
initialize the variable @code{x-pointer-shape}.

@item @code{selectionPointer} (class @code{Cursor}): cursor-name
The cursor to use when the mouse is over a selectable text region (an
extent with the @samp{highlight} property; for example, an Info
cross-reference).  This resource is used to initialize the variable
@code{x-selection-pointer-shape}.

@item @code{spacePointer} (class @code{Cursor}): cursor-name
The cursor to use when the mouse is over a blank space in a buffer (that
is, after the end of a line or after the end-of-file).  This resource is
used to initialize the variable @code{x-nontext-pointer-shape}.

@item @code{modeLinePointer} (class @code{Cursor}): cursor-name
The cursor to use when the mouse is over a modeline.  This resource is
used to initialize the variable @code{x-mode-pointer-shape}.

@item @code{gcPointer} (class @code{Cursor}): cursor-name
The cursor to display when a garbage-collection is in progress.  This
resource is used to initialize the variable @code{x-gc-pointer-shape}.

@item @code{scrollbarPointer} (class @code{Cursor}): cursor-name
The cursor to use when the mouse is over the scrollbar.  This resource
is used to initialize the variable @code{x-scrollbar-pointer-shape}.

@item @code{pointerColor} (class @code{Foreground}): color-name
@itemx @code{pointerBackground} (class @code{Background}): color-name
The foreground and background colors of the mouse cursor.  These
resources are used to initialize the variables
@code{x-pointer-foreground-color} and @code{x-pointer-background-color}.
@end table

@node Face Resources
@subsection Face Resources

The attributes of faces are also per-frame. They can be specified as:

@example
Emacs.FACE_NAME.parameter: value
@end example
@noindent

or

@example
Emacs*FRAME_NAME.FACE_NAME.parameter: value
@end example
@noindent

Faces accept the following resources:

@table @asis
@item @code{attributeFont} (class @code{AttributeFont}): font-name
The font of this face.

@item @code{attributeForeground} (class @code{AttributeForeground}): color-name
@itemx @code{attributeBackground} (class @code{AttributeBackground}): color-name
The foreground and background colors of this face.

@item @code{attributeBackgroundPixmap} (class @code{AttributeBackgroundPixmap}): file-name
The name of an @sc{XBM} file (or @sc{XPM} file, if your version of Emacs
supports @sc{XPM}), to use as a background stipple.

@item @code{attributeUnderline} (class @code{AttributeUnderline}): boolean
Whether text in this face should be underlined.
@end table

All text is displayed in some face, defaulting to the face named
@code{default}.  To set the font of normal text, use
@code{Emacs*default.attributeFont}. To set it in the frame named
@code{fred}, use @code{Emacs*fred.default.attributeFont}.

These are the names of the predefined faces:

@table @code
@item default
Everything inherits from this.

@item bold
If this is not specified in the resource database, Emacs tries to find a
bold version of the font of the default face.

@item italic
If this is not specified in the resource database, Emacs tries to find
an italic version of the font of the default face.

@item bold-italic
If this is not specified in the resource database, Emacs tries to find a
bold-italic version of the font of the default face.

@item modeline
This is the face that the modeline is displayed in.  If not specified in
the resource database, it is determined from the default face by
reversing the foreground and background colors.

@item highlight
This is the face that highlighted extents (for example, Info
cross-references and possible completions, when the mouse passes over
them) are displayed in.

@item left-margin
@itemx right-margin
These are the faces that the left and right annotation margins are
displayed in.

@item zmacs-region
This is the face that mouse selections are displayed in.
 
@item isearch
This is the face that the matched text being searched for is displayed
in.

@item info-node
This is the face of info menu items.  If unspecified, it is copied from
@code{bold-italic}.

@item info-xref
This is the face of info cross-references.  If unspecified, it is copied
from @code{bold}. (Note that, when the mouse passes over a
cross-reference, the cross-reference's face is determined from a
combination of the @code{info-xref} and @code{highlight} faces.)
@end table

Other packages might define their own faces; to see a list of all faces,
use any of the interactive face-manipulation commands such as
@code{set-face-font} and type @samp{?} when you are prompted for the
name of a face.

If the @code{bold}, @code{italic}, and @code{bold-italic} faces are not
specified in the resource database, then XEmacs attempts to derive them
from the font of the default face.  It can only succeed at this if you
have specified the default font using the XLFD (X Logical Font
Description) format, which looks like

@example
*-courier-medium-r-*-*-*-120-*-*-*-*-*-*
@end example
@noindent

If you use any of the other, less strict font name formats, some of which
look like

@example
lucidasanstypewriter-12
fixed
9x13
@end example

then XEmacs won't be able to guess the names of the bold and italic
versions.  All X fonts can be referred to via XLFD-style names, so you
should use those forms.  See the man pages for @samp{X(1)},
@samp{xlsfonts(1)}, and @samp{xfontsel(1)}.

@node Widgets
@subsection Widgets

There are several structural widgets between the terminal EmacsFrame
widget and the top level ApplicationShell; the exact names and types of
these widgets change from release to release (for example, they changed
between 19.8 and 19.9, 19.9 and 19.10, and 19.10 and 19.12) and are
subject to further change in the future, so you should avoid mentioning
them in your resource database.  The above-mentioned syntaxes should be
forward- compatible.  As of 19.13, the exact widget hierarchy is as
follows:

@example
INVOCATION-NAME            "shell"       "container"     FRAME-NAME
x-emacs-application-class  "EmacsShell"  "EmacsManager"  "EmacsFrame"
@end example

where INVOCATION-NAME is the terminal component of the name of the
XEmacs executable (usually @samp{xemacs}), and
@samp{x-emacs-application-class} is generally @samp{Emacs}.

@node Menubar Resources
@subsection Menubar Resources

As the menubar is implemented as a widget which is not a part of XEacs
proper, it does not use the fac" mechanism for specifying fonts and
colors: It uses whatever resources are appropriate to the type of widget
which is used to implement it.

If Emacs was compiled to use only the Motif-lookalike menu widgets, then one
way to specify the font of the menubar would be

@example
Emacs*menubar*font: *-courier-medium-r-*-*-*-120-*-*-*-*-*-*
@end example

If the Motif library is being used, then one would have to use 

@example
Emacs*menubar*fontList: *-courier-medium-r-*-*-*-120-*-*-*-*-*-*
@end example

because the Motif library uses the @code{fontList} resource name instead
of @code{font}, which has subtly different semantics.

The same is true of the scrollbars: They accept whichever resources are 
appropriate for the toolkit in use.