@c -*-texinfo-*-
@c This is part of the GNU Emacs Lisp Reference Manual.
-@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995, 1998, 1999, 2002, 2003,
+@c 2004, 2005, 2006 Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
@setfilename ../info/buffers
@node Buffers, Windows, Backups and Auto-Saving, Top
switch visibly to a different buffer so that the user can edit it. For
that, you must use the functions described in @ref{Displaying Buffers}.
- @strong{Note:} Lisp functions that change to a different current buffer
+ @strong{Warning:} Lisp functions that change to a different current buffer
should not depend on the command loop to set it back afterwards.
Editing commands written in Emacs Lisp can be called from other programs
as well as from the command loop; it is convenient for the caller if
existing buffer.
@end defun
-@defspec save-current-buffer body...
+@defspec save-current-buffer body@dots{}
The @code{save-current-buffer} special form saves the identity of the
current buffer, evaluates the @var{body} forms, and finally restores
that buffer as current. The return value is the value of the last
remains current.
@end defspec
-@defmac with-current-buffer buffer body...
+@defmac with-current-buffer buffer-or-name body@dots{}
The @code{with-current-buffer} macro saves the identity of the current
-buffer, makes @var{buffer} current, evaluates the @var{body} forms, and
-finally restores the buffer. The return value is the value of the last
-form in @var{body}. The current buffer is restored even in case of an
-abnormal exit via @code{throw} or error (@pxref{Nonlocal Exits}).
+buffer, makes @var{buffer-or-name} current, evaluates the @var{body}
+forms, and finally restores the buffer. The return value is the value
+of the last form in @var{body}. The current buffer is restored even
+in case of an abnormal exit via @code{throw} or error (@pxref{Nonlocal
+Exits}).
+
+An error is signaled if @var{buffer-or-name} does not identify an
+existing buffer.
@end defmac
-@defmac with-temp-buffer body...
+@defmac with-temp-buffer body@dots{}
+@anchor{Definition of with-temp-buffer}
The @code{with-temp-buffer} macro evaluates the @var{body} forms
with a temporary buffer as the current buffer. It saves the identity of
the current buffer, creates a temporary buffer and makes it current,
The current buffer is restored even in case of an abnormal exit via
@code{throw} or error (@pxref{Nonlocal Exits}).
-@end defmac
-See also @code{with-temp-file} in @ref{Writing to Files}.
+See also @code{with-temp-file} in @ref{Definition of with-temp-file,,
+Writing to Files}.
+@end defmac
@node Buffer Names
@section Buffer Names
@deffn Command rename-buffer newname &optional unique
This function renames the current buffer to @var{newname}. An error
-is signaled if @var{newname} is not a string, or if there is already a
-buffer with that name. The function returns @var{newname}.
+is signaled if @var{newname} is not a string.
@c Emacs 19 feature
Ordinarily, @code{rename-buffer} signals an error if @var{newname} is
@var{newname} to make a name that is not in use. Interactively, you can
make @var{unique} non-@code{nil} with a numeric prefix argument.
(This is how the command @code{rename-uniquely} is implemented.)
+
+This function returns the name actually given to the buffer.
@end deffn
@defun get-buffer buffer-or-name
@end defun
@c Emacs 19 feature
-@defun generate-new-buffer-name starting-name &rest ignore
+@defun generate-new-buffer-name starting-name &optional ignore
This function returns a name that would be unique for a new buffer---but
does not create the buffer. It starts with @var{starting-name}, and
produces a name not currently in use for any buffer by appending a
-number inside of @samp{<@dots{}>}.
+number inside of @samp{<@dots{}>}. It starts at 2 and keeps
+incrementing the number until it is not the name of an existing buffer.
If the optional second argument @var{ignore} is non-@code{nil}, it
-should be a string; it makes a difference if it is a name in the
-sequence of names to be tried. That name will be considered acceptable,
-if it is tried, even if a buffer with that name exists. Thus, if
-buffers named @samp{foo}, @samp{foo<2>}, @samp{foo<3>} and @samp{foo<4>}
-exist,
+should be a string, a potential buffer name. It means to consider
+that potential buffer acceptable, if it is tried, even it is the name
+of an existing buffer (which would normally be rejected). Thus, if
+buffers named @samp{foo}, @samp{foo<2>}, @samp{foo<3>} and
+@samp{foo<4>} exist,
@example
(generate-new-buffer-name "foo")
@end defvar
@defvar buffer-file-truename
-This buffer-local variable holds the truename of the file visited in the
-current buffer, or @code{nil} if no file is visited. It is a permanent
-local, unaffected by @code{kill-all-local-variables}. @xref{Truenames}.
+This buffer-local variable holds the abbreviated truename of the file
+visited in the current buffer, or @code{nil} if no file is visited.
+It is a permanent local, unaffected by
+@code{kill-all-local-variables}. @xref{Truenames}, and
+@ref{Definition of abbreviate-file-name}.
@end defvar
@defvar buffer-file-number
all files accessible on the system. See the function
@code{file-attributes}, in @ref{File Attributes}, for more information
about them.
+
+If @code{buffer-file-name} is the name of a symbolic link, then both
+numbers refer to the recursive target.
@end defvar
@defun get-file-buffer filename
there is no such buffer, it returns @code{nil}. The argument
@var{filename}, which must be a string, is expanded (@pxref{File Name
Expansion}), then compared against the visited file names of all live
-buffers.
+buffers. Note that the buffer's @code{buffer-file-name} must match
+the expansion of @var{filename} exactly. This function will not
+recognize other names for the same file.
@example
@group
such buffer in the buffer list.
@end defun
+@defun find-buffer-visiting filename &optional predicate
+This is like @code{get-file-buffer}, except that it can return any
+buffer visiting the file @emph{possibly under a different name}. That
+is, the buffer's @code{buffer-file-name} does not need to match the
+expansion of @var{filename} exactly, it only needs to refer to the
+same file. If @var{predicate} is non-@code{nil}, it should be a
+function of one argument, a buffer visiting @var{filename}. The
+buffer is only considered a suitable return value if @var{predicate}
+returns non-@code{nil}. If it can not find a suitable buffer to
+return, @code{find-buffer-visiting} returns @code{nil}.
+@end defun
+
@deffn Command set-visited-file-name filename &optional no-query along-with-file
If @var{filename} is a non-empty string, this function changes the
name of the file visited in the current buffer to @var{filename}. (If the
If @var{filename} is @code{nil} or the empty string, that stands for
``no visited file''. In this case, @code{set-visited-file-name} marks
-the buffer as having no visited file.
-
-Normally, this function asks the user for confirmation if the specified
-file already exists. If @var{no-query} is non-@code{nil}, that prevents
-asking this question.
-
-If @var{along-with-file} is non-@code{nil}, that means to assume that the
-former visited file has been renamed to @var{filename}.
+the buffer as having no visited file, without changing the buffer's
+modified flag.
+
+Normally, this function asks the user for confirmation if there
+already is a buffer visiting @var{filename}. If @var{no-query} is
+non-@code{nil}, that prevents asking this question. If there already
+is a buffer visiting @var{filename}, and the user confirms or
+@var{query} is non-@code{nil}, this function makes the new buffer name
+unique by appending a number inside of @samp{<@dots{}>} to @var{filename}.
+
+If @var{along-with-file} is non-@code{nil}, that means to assume that
+the former visited file has been renamed to @var{filename}. In this
+case, the command does not change the buffer's modified flag, nor the
+buffer's recorded last file modification time as reported by
+@code{visited-file-modtime} (@pxref{Modification Time}). If
+@var{along-with-file} is @code{nil}, this function clears the recorded
+last file modification time, after which @code{visited-file-modtime}
+returns zero.
@c Wordy to avoid overfull hbox. --rjc 16mar92
When the function @code{set-visited-file-name} is called interactively, it
@end example
@end defun
-@deffn Command not-modified
-This command marks the current buffer as unmodified, and not needing to
-be saved. With prefix arg, it marks the buffer as modified, so that it
-will be saved at the next suitable occasion.
+@defun restore-buffer-modified-p flag
+Like @code{set-buffer-modified-p}, but does not force redisplay
+of mode lines.
+@end defun
+
+@deffn Command not-modified &optional arg
+This command marks the current buffer as unmodified, and not needing
+to be saved. If @var{arg} is non-@code{nil}, it marks the buffer as
+modified, so that it will be saved at the next suitable occasion.
+Interactively, @var{arg} is the prefix argument.
Don't use this function in programs, since it prints a message in the
echo area; use @code{set-buffer-modified-p} (above) instead.
This function returns @var{buffer}'s modification-count. This is a
counter that increments every time the buffer is modified. If
@var{buffer} is @code{nil} (or omitted), the current buffer is used.
+The counter can wrap around occasionally.
@end defun
@node Modification Time
The function returns @code{t} if the last actual modification time and
Emacs's recorded modification time are the same, @code{nil} otherwise.
+It also returns @code{t} if the buffer has no recorded last
+modification time, that is if @code{visited-file-modtime} would return
+zero.
+
+It always returns @code{t} for buffers that are not visiting a file,
+even if @code{visited-file-modtime} returns a non-zero value. For
+instance, it always returns @code{t} for dired buffers. It returns
+@code{t} for buffers that are visiting a file that does not exist and
+never existed, but @code{nil} for file-visiting buffers whose file has
+been deleted.
@end defun
@defun clear-visited-file-modtime
@c Emacs 19 feature
@defun visited-file-modtime
-This function returns the buffer's recorded last file modification time,
-as a list of the form @code{(@var{high} . @var{low})}. (This is the
-same format that @code{file-attributes} uses to return time values; see
-@ref{File Attributes}.)
+This function returns the current buffer's recorded last file
+modification time, as a list of the form @code{(@var{high} @var{low})}.
+(This is the same format that @code{file-attributes} uses to return
+time values; see @ref{File Attributes}.)
+
+If the buffer has no recorded last modification time, this function
+returns zero. This case occurs, for instance, if the buffer is not
+visiting a file or if the time has been explicitly cleared by
+@code{clear-visited-file-modtime}. Note, however, that
+@code{visited-file-modtime} returns a list for some non-file buffers
+too. For instance, in a Dired buffer listing a directory, it returns
+the last modification time of that directory, as recorded by Dired.
+
+For a new buffer visiting a not yet existing file, @var{high} is
+@minus{}1 and @var{low} is 65535, that is,
+@ifnottex
+@w{2**16 - 1.}
+@end ifnottex
+@tex
+@math{2^{16}-1}.
+@end tex
@end defun
@c Emacs 19 feature
is not @code{nil}, and otherwise to the last modification time of the
visited file.
-If @var{time} is not @code{nil}, it should have the form
+If @var{time} is neither @code{nil} nor zero, it should have the form
@code{(@var{high} . @var{low})} or @code{(@var{high} @var{low})}, in
either case containing two integers, each of which holds 16 bits of the
time.
@end defvar
@defvar inhibit-read-only
-If this variable is non-@code{nil}, then read-only buffers and read-only
-characters may be modified. Read-only characters in a buffer are those
-that have non-@code{nil} @code{read-only} properties (either text
-properties or overlay properties). @xref{Special Properties}, for more
-information about text properties. @xref{Overlays}, for more
-information about overlays and their properties.
+If this variable is non-@code{nil}, then read-only buffers and,
+depending on the actual value, some or all read-only characters may be
+modified. Read-only characters in a buffer are those that have
+non-@code{nil} @code{read-only} properties (either text properties or
+overlay properties). @xref{Special Properties}, for more information
+about text properties. @xref{Overlays}, for more information about
+overlays and their properties.
If @code{inhibit-read-only} is @code{t}, all @code{read-only} character
properties have no effect. If @code{inhibit-read-only} is a list, then
of the list (comparison is done with @code{eq}).
@end defvar
-@deffn Command toggle-read-only
-This command changes whether the current buffer is read-only. It is
+@deffn Command toggle-read-only &optional arg
+This command toggles whether the current buffer is read-only. It is
intended for interactive use; do not use it in programs. At any given
point in a program, you should know whether you want the read-only flag
on or off; so you can set @code{buffer-read-only} explicitly to the
proper value, @code{t} or @code{nil}.
+
+If @var{arg} is non-@code{nil}, it should be a raw prefix argument.
+@code{toggle-read-only} sets @code{buffer-read-only} to @code{t} if
+the numeric value of that prefix argument is positive and to
+@code{nil} otherwise. @xref{Prefix Command Arguments}.
@end deffn
@defun barf-if-buffer-read-only
This function signals a @code{buffer-read-only} error if the current
-buffer is read-only. @xref{Interactive Call}, for another way to
+buffer is read-only. @xref{Using Interactive}, for another way to
signal an error if the current buffer is read-only.
@end defun
@section The Buffer List
@cindex buffer list
- The @dfn{buffer list} is a list of all live buffers. Creating a
-buffer adds it to this list, and killing a buffer removes it. The
-order of the buffers in the list is based primarily on how recently
-each buffer has been displayed in the selected window. Buffers move
-to the front of the list when they are selected (selecting a window
-that already displays the buffer counts as selecting the buffer), and
-to the end when they are buried (see @code{bury-buffer}, below).
-Several functions, notably @code{other-buffer}, use this ordering. A
-buffer list displayed for the user also follows this order.
+ The @dfn{buffer list} is a list of all live buffers. The order of
+the buffers in the list is based primarily on how recently each buffer
+has been displayed in a window. Several functions, notably
+@code{other-buffer}, use this ordering. A buffer list displayed for
+the user also follows this order.
+ Creating a buffer adds it to the end of the buffer list, and killing
+a buffer removes it. Buffers move to the front of the list when they
+are selected for display in a window (@pxref{Displaying Buffers}), and
+to the end when they are buried (see @code{bury-buffer}, below).
+There are no functions available to the Lisp programmer which directly
+manipulate the buffer list.
+
In addition to the fundamental Emacs buffer list, each frame has its
own version of the buffer list, in which the buffers that have been
selected in that frame come first, starting with the buffers most
recently selected @emph{in that frame}. (This order is recorded in
-@var{frame}'s @code{buffer-list} frame parameter; see @ref{Window Frame
+@var{frame}'s @code{buffer-list} frame parameter; see @ref{Buffer
Parameters}.) The buffers that were never selected in @var{frame} come
afterward, ordered according to the fundamental Emacs buffer list.
If @var{frame} has a non-@code{nil} @code{buffer-predicate} parameter,
then @code{other-buffer} uses that predicate to decide which buffers to
consider. It calls the predicate once for each buffer, and if the value
-is @code{nil}, that buffer is ignored. @xref{Window Frame Parameters}.
+is @code{nil}, that buffer is ignored. @xref{Buffer Parameters}.
@c Emacs 19 feature
If @var{visible-ok} is @code{nil}, @code{other-buffer} avoids returning
This function puts @var{buffer-or-name} at the end of the buffer list,
without changing the order of any of the other buffers on the list.
This buffer therefore becomes the least desirable candidate for
-@code{other-buffer} to return.
+@code{other-buffer} to return. The argument can be either a buffer
+itself or the name of one.
@code{bury-buffer} operates on each frame's @code{buffer-list} parameter
as well as the frame-independent Emacs buffer list; therefore, the
subprocess can also create a buffer (@pxref{Processes}).
@defun get-buffer-create name
-This function returns a buffer named @var{name}. It returns an existing
+This function returns a buffer named @var{name}. It returns a live
buffer with that name, if one exists; otherwise, it creates a new
buffer. The buffer does not become the current buffer---this function
does not change which buffer is current.
-An error is signaled if @var{name} is not a string.
+If @var{name} is a buffer instead of a string, it is returned, even if
+it is dead. An error is signaled if @var{name} is neither a string
+nor a buffer.
@example
@group
@end group
@end example
-The major mode for the new buffer is set to Fundamental mode. The
-variable @code{default-major-mode} is handled at a higher level.
+The major mode for a newly created buffer is set to Fundamental mode.
+The variable @code{default-major-mode} is handled at a higher level.
@xref{Auto Major Mode}.
@end defun
@cindex killing buffers
@cindex buffers, killing
- @dfn{Killing a buffer} makes its name unknown to Emacs and makes its
-text space available for other use.
+ @dfn{Killing a buffer} makes its name unknown to Emacs and makes the
+memory space it occupied available for other use.
The buffer object for the buffer that has been killed remains in
existence as long as anything refers to it, but it is specially marked
@deffn Command kill-buffer buffer-or-name
This function kills the buffer @var{buffer-or-name}, freeing all its
-memory for other uses or to be returned to the operating system. It
-returns @code{nil}.
+memory for other uses or to be returned to the operating system. If
+@var{buffer-or-name} is @code{nil}, it kills the current buffer.
Any processes that have this buffer as the @code{process-buffer} are
sent the @code{SIGHUP} signal, which normally causes them to terminate.
Killing a buffer that is already dead has no effect.
+This function returns @code{t} if it actually killed the buffer. It
+returns @code{nil} if the user refuses to confirm or if
+@var{buffer-or-name} was already dead.
+
@smallexample
(kill-buffer "foo.unchanged")
- @result{} nil
+ @result{} t
(kill-buffer "foo.changed")
---------- Buffer: Minibuffer ----------
Buffer foo.changed modified; kill anyway? (yes or no) @kbd{yes}
---------- Buffer: Minibuffer ----------
- @result{} nil
+ @result{} t
@end smallexample
@end deffn
@defvar buffer-offer-save
This variable, if non-@code{nil} in a particular buffer, tells
-@code{save-buffers-kill-emacs} and @code{save-some-buffers} to offer to
-save that buffer, just as they offer to save file-visiting buffers. The
-variable @code{buffer-offer-save} automatically becomes buffer-local
-when set for any reason. @xref{Buffer-Local Variables}.
+@code{save-buffers-kill-emacs} and @code{save-some-buffers} (if the
+second optional argument to that function is @code{t}) to offer to
+save that buffer, just as they offer to save file-visiting buffers.
+@xref{Definition of save-some-buffers}. The variable
+@code{buffer-offer-save} automatically becomes buffer-local when set
+for any reason. @xref{Buffer-Local Variables}.
+@end defvar
+
+@defvar buffer-save-without-query
+This variable, if non-@code{nil} in a particular buffer, tells
+@code{save-buffers-kill-emacs} and @code{save-some-buffers} to save
+this buffer (if it's modified) without asking the user. The variable
+automatically becomes buffer-local when set for any reason.
@end defvar
+@defun buffer-live-p object
+This function returns @code{t} if @var{object} is a buffer which has
+not been killed, @code{nil} otherwise.
+@end defun
+
@node Indirect Buffers
@section Indirect Buffers
@cindex indirect buffers
themselves.
In all other respects, the indirect buffer and its base buffer are
-completely separate. They have different names, different values of
-point, different narrowing, different markers and overlays (though
+completely separate. They have different names, independent values of
+point, independent narrowing, independent markers and overlays (though
inserting or deleting text in either buffer relocates the markers and
-overlays for both), different major modes, and different buffer-local
-variables.
+overlays for both), independent major modes, and independent
+buffer-local variable bindings.
An indirect buffer cannot visit a file, but its base buffer can. If
you try to save the indirect buffer, that actually saves the base
the base buffer effectively kills the indirect buffer in that it cannot
ever again be the current buffer.
-@deffn Command make-indirect-buffer base-buffer name
-This creates an indirect buffer named @var{name} whose base buffer
-is @var{base-buffer}. The argument @var{base-buffer} may be a buffer
-or a string.
+@deffn Command make-indirect-buffer base-buffer name &optional clone
+This creates and returns an indirect buffer named @var{name} whose
+base buffer is @var{base-buffer}. The argument @var{base-buffer} may
+be a live buffer or the name (a string) of an existing buffer. If
+@var{name} is the name of an existing buffer, an error is signaled.
+
+If @var{clone} is non-@code{nil}, then the indirect buffer originally
+shares the ``state'' of @var{base-buffer} such as major mode, minor
+modes, buffer local variables and so on. If @var{clone} is omitted
+or @code{nil} the indirect buffer's state is set to the default state
+for new buffers.
If @var{base-buffer} is an indirect buffer, its base buffer is used as
-the base for the new buffer.
+the base for the new buffer. If, in addition, @var{clone} is
+non-@code{nil}, the initial state is copied from the actual base
+buffer, not from @var{base-buffer}.
@end deffn
-@defun buffer-base-buffer buffer
-This function returns the base buffer of @var{buffer}. If @var{buffer}
-is not indirect, the value is @code{nil}. Otherwise, the value is
-another buffer, which is never an indirect buffer.
+@defun clone-indirect-buffer newname display-flag &optional norecord
+This function creates and returns a new indirect buffer that shares
+the current buffer's base buffer and copies the rest of the current
+buffer's attributes. (If the current buffer is not indirect, it is
+used as the base buffer.)
+
+If @var{display-flag} is non-@code{nil}, that means to display the new
+buffer by calling @code{pop-to-buffer}. If @var{norecord} is
+non-@code{nil}, that means not to put the new buffer to the front of
+the buffer list.
+@end defun
+
+@defun buffer-base-buffer &optional buffer
+This function returns the base buffer of @var{buffer}, which defaults
+to the current buffer. If @var{buffer} is not indirect, the value is
+@code{nil}. Otherwise, the value is another buffer, which is never an
+indirect buffer.
@end defun
@node Buffer Gap
@defun gap-size
This function returns the current gap size of the current buffer.
@end defun
+
+@ignore
+ arch-tag: 2e53cfab-5691-41f6-b5a8-9c6a3462399c
+@end ignore