@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
@c Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
-@c 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
+@c 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../../info/customize
@node Customization, Loading, Macros, Top
Use @var{label}, a string, instead of the item's name, to label the
item in customization menus and buffers. @strong{Don't use a tag
which is substantially different from the item's real name; that would
-cause confusion.} One legitimate case for use of @code{:tag} is to
-specify a dash where normally a hyphen would be converted to a space:
-
-@example
-(defcustom cursor-in-non-selected-windows @dots{}
- :tag "Cursor In Non-selected Windows"
-@end example
+cause confusion.}
@kindex group@r{, customization keyword}
@item :group @var{group}
Use @code{defcustom} to declare user-customizable variables.
@defmac defcustom option standard doc [keyword value]@dots{}
-This construct declares @var{option} as a customizable user option
-variable. You should not quote @var{option}. The argument @var{doc}
-specifies the documentation string for the variable. There is no need
-to start it with a @samp{*}, because @code{defcustom} automatically
-marks @var{option} as a @dfn{user option} (@pxref{Defining
-Variables}).
+This macro declares @var{option} as a customizable @dfn{user option}.
+You should not quote @var{option}.
+
+This causes the function @code{user-variable-p} to return @code{t}
+when given @var{option} as an argument. @xref{Defining Variables}.
+The argument @var{doc} specifies the documentation string for the
+variable. (Note that there is no need to start @var{doc} with a
+@samp{*}.)
The argument @var{standard} is an expression that specifies the
standard value for @var{option}. Evaluating the @code{defcustom} form
arranges to set the variable unconditionally, without testing whether
its value is void. (The same feature applies to @code{defvar}.)
@xref{Defining Variables}.
+
+If you put a @code{defcustom} in a file that is preloaded at dump time
+(@pxref{Building Emacs}), and the standard value installed for the
+variable at that time might not be correct, use
+@code{custom-reevaluate-setting}, described below, to re-evaluate the
+standard value during or after Emacs startup.
@end defmac
@code{defcustom} accepts the following additional keywords:
@item :risky @var{value}
@kindex risky@r{, @code{defcustom} keyword}
-Set this variable's @code{risky-local-variable} property to @var{value}.
+Set this variable's @code{risky-local-variable} property to
+@var{value} (@pxref{File Local Variables}).
@item :safe @var{function}
@kindex safe@r{, @code{defcustom} keyword}
-Set this variable's @code{safe-local-variable} property to @var{function}.
+Set this variable's @code{safe-local-variable} property to
+@var{function} (@pxref{File Local Variables}).
@item :set-after @var{variables}
@kindex set-after@r{, @code{defcustom} keyword}
those other variables already have their intended values.
@end table
- The @code{:require} keyword is useful for an option that turns on the
-operation of a certain feature. Assuming that the package is coded to
-check the value of the option, you still need to arrange for the package
-to be loaded. You can do that with @code{:require}. @xref{Common
-Keywords}. Here is an example, from the library @file{saveplace.el}:
+ It is useful to specify the @code{:require} keyword for an option
+that ``turns on'' a certain feature. This causes Emacs to load the
+feature, if it is not already loaded, whenever the option is set.
+@xref{Common Keywords}. Here is an example, from the library
+@file{saveplace.el}:
@example
(defcustom save-place nil
Internally, @code{defcustom} uses the symbol property
@code{standard-value} to record the expression for the standard value,
-and @code{saved-value} to record the value saved by the user with the
-customization buffer. Both properties are actually lists whose car is
-an expression which evaluates to the value.
+@code{saved-value} to record the value saved by the user with the
+customization buffer, and @code{customized-value} to record the value
+set by the user with the customization buffer, but not saved.
+@xref{Property Lists}. These properties are lists, the car of which
+is an expression that evaluates to the value.
+
+@defun custom-reevaluate-setting symbol
+This function re-evaluates the standard value of @var{symbol}, which
+should be a user option declared via @code{defcustom}. (If the
+variable was customized, this function re-evaluates the saved value
+instead.) This is useful for customizable options that are defined
+before their value could be computed correctly, such as variables
+defined in packages that are loaded at dump time, but depend on the
+run-time information. For example, the value could be a file whose
+precise name depends on the hierarchy of files when Emacs runs, or a
+name of a program that needs to be searched at run time.
+
+A good place to put calls to this function is in the function
+@code{command-line} that is run during startup (@pxref{Startup Summary})
+or in the various hooks it calls.
+@end defun
@node Customization Types
@section Customization Types
the symbol. Between the type symbol and its arguments, you can
optionally write keyword-value pairs (@pxref{Type Keywords}).
- Some of the type symbols do not use any arguments; those are called
+ Some type symbols do not use any arguments; those are called
@dfn{simple types}. For a simple type, if you do not use any
keyword-value pairs, you can omit the parentheses around the type
symbol. For example just @code{string} as a customization type is
equivalent to @code{(string)}.
+ All customization types are implemented as widgets; see @ref{Top, ,
+Introduction, widget, The Emacs Widget Library}, for details.
+
@menu
* Simple Types::
* Composite Types::
* Defining New Types::
@end menu
-All customization types are implemented as widgets; see @ref{Top, ,
-Introduction, widget, The Emacs Widget Library}, for details.
-
@node Simple Types
@subsection Simple Types