@c Copyright (C) 1990-1995, 1998-1999, 2001-2012
@c Free Software Foundation, Inc.
@c See the file elisp.texi for copying conditions.
-@setfilename ../../info/files
@node Files, Backups and Auto-Saving, Documentation, Top
@comment node-name, next, previous, up
@chapter Files
In spite of the distinction between files and buffers, people often
refer to a file when they mean a buffer and vice-versa. Indeed, we say,
-``I am editing a file,'' rather than, ``I am editing a buffer that I
-will soon save as a file of the same name.'' Humans do not usually need
+``I am editing a file'', rather than, ``I am editing a buffer that I
+will soon save as a file of the same name''. Humans do not usually need
to make the distinction explicit. When dealing with a computer program,
however, it is good to keep the distinction in mind.
@defopt require-final-newline
This variable determines whether files may be written out that do
@emph{not} end with a newline. If the value of the variable is
-@code{t}, then @code{save-buffer} silently adds a newline at the end of
-the file whenever the buffer being saved does not already end in one.
-If the value of the variable is non-@code{nil}, but not @code{t}, then
-@code{save-buffer} asks the user whether to add a newline each time the
-case arises.
+@code{t}, then @code{save-buffer} silently adds a newline at the end
+of the buffer whenever it does not already end in one. If the value
+is @code{visit}, Emacs adds a missing newline just after it visits the
+file. If the value is @code{visit-save}, Emacs adds a missing newline
+both on visiting and on saving. For any other non-@code{nil} value,
+@code{save-buffer} asks the user whether to add a newline each time
+the case arises.
If the value of the variable is @code{nil}, then @code{save-buffer}
doesn't add newlines at all. @code{nil} is the default value, but a few
stored in the same directory as the file you are editing.
When you access files using NFS, there may be a small probability that
-you and another user will both lock the same file ``simultaneously.''
+you and another user will both lock the same file ``simultaneously''.
If this happens, it is possible for the two users to make changes
simultaneously, but Emacs will still warn the user who saves second.
Also, the detection of modification of a buffer visiting a file changed
File locking is not supported on some systems. On systems that do not
support it, the functions @code{lock-buffer}, @code{unlock-buffer} and
-@code{file-locked-p} do nothing and return @code{nil}.
+@code{file-locked-p} do nothing and return @code{nil}. It is also
+possible to disable locking, by setting the variable @code{create-lockfiles}.
+
+@defopt create-lockfiles
+If this variable is @code{nil}, Emacs does not lock files.
+@end defopt
@defun ask-user-about-lock file other-user
This function is called when the user tries to modify @var{file}, but it
@defun file-equal-p file1 file2
This function returns @code{t} if the files @var{file1} and
-@var{file2} name the same file. Two ordinary files are considered to
-be the same if the function @code{file-attributes} (@pxref{File
-Attributes}) returns @code{equal} values for them.
+@var{file2} name the same file. If @var{file1} or @var{file2} does
+not exist, the return value is unspecified.
@end defun
-@defun file-subdir-of-p dir1 dir2
-This function returns @code{t} if directory @var{dir1} is a
-subdirectory of @var{dir2}, or if @var{dir1} and @var{dir2} are the
-same directory. It compares the @code{file-truename} values of the
-two directories (@pxref{Truenames}). If @var{dir2}
-do not name an existing directory, the return value is @code{nil}.
+@defun file-in-directory-p file dir
+This function returns @code{t} if @var{file} is a file in directory
+@var{dir}, or in a subdirectory of @var{dir}. It also returns
+@code{t} if @var{file} and @var{dir} are the same directory. It
+compares the @code{file-truename} values of the two directories
+(@pxref{Truenames}). If @var{dir} does not name an existing
+directory, the return value is @code{nil}.
@end defun
@node Truenames
@end defun
@defun file-name-extension filename &optional period
-This function returns @var{filename}'s final ``extension,'' if any,
+This function returns @var{filename}'s final ``extension'', if any,
after applying @code{file-name-sans-versions} to remove any
version/backup part. The extension, in a file name, is the part that
follows the last @samp{.} in the last name component (minus any
results.
@c Wordy to avoid overfull hbox. --rjc 15mar92
-Here we assume that the environment variable @code{HOME}, which holds
+Here we assume that the environment variable @env{HOME}, which holds
the user's home directory name, has value @samp{/xcssun/users/rms}.
@example
the proper directory before calling @code{make-temp-file}.
@defopt temporary-file-directory
-@cindex @code{TMPDIR} environment variable
-@cindex @code{TMP} environment variable
-@cindex @code{TEMP} environment variable
+@cindex @env{TMPDIR} environment variable
+@cindex @env{TMP} environment variable
+@cindex @env{TEMP} environment variable
This variable specifies the directory name for creating temporary files.
Its value should be a directory name (@pxref{Directory Names}), but it
is good for Lisp programs to cope if the value is a directory's file
@code{expand-file-name} is a good way to achieve that.
The default value is determined in a reasonable way for your operating
-system; it is based on the @code{TMPDIR}, @code{TMP} and @code{TEMP}
+system; it is based on the @env{TMPDIR}, @env{TMP} and @env{TEMP}
environment variables, with a fall-back to a system-dependent name if
none of these variables is defined.
@code{file-name-nondirectory},
@code{file-name-sans-versions}, @code{file-newer-than-file-p},
@code{file-ownership-preserved-p},
-@code{file-readable-p}, @code{file-regular-p}, @code{file-subdir-of-p},
+@code{file-readable-p}, @code{file-regular-p}, @code{file-in-directory-p},
@code{file-symlink-p}, @code{file-truename}, @code{file-writable-p},
@code{file-equal-p}, @code{find-backup-file-name},
@c Not sure why it was here: @code{find-file-noselect},@*
possibly others to be added in the future. It need not implement all
these operations itself---when it has nothing special to do for a
certain operation, it can reinvoke the primitive, to handle the
-operation ``in the usual way.'' It should always reinvoke the primitive
+operation ``in the usual way''. It should always reinvoke the primitive
for an operation it does not recognize. Here's one way to do this:
@smallexample
@example
(defun display-time-file-nonempty-p (file)
- (let ((remote-file-name-inhibit-cache (- display-time-interval 5)))
+ (let ((remote-file-name-inhibit-cache
+ (- display-time-interval 5)))
(and (file-exists-p file)
(< 0 (nth 7 (file-attributes (file-chase-links file)))))))
@end example
This command writes the current buffer contents into the file @var{file}
in a format based on @var{format}, which is a list of format names. It
constructs the actual format starting from @var{format}, then appending
-any elements from the value of @code{buffer-file-format} with a non-nil
-@var{preserve} flag (see above), if they are not already present in
-@var{format}. It then updates @code{buffer-file-format} with this
-format, making it the default for future saves. Except for the
+any elements from the value of @code{buffer-file-format} with a
+non-@code{nil} @var{preserve} flag (see above), if they are not already
+present in @var{format}. It then updates @code{buffer-file-format} with
+this format, making it the default for future saves. Except for the
@var{format} argument, this command is similar to @code{write-file}. In
particular, @var{confirm} has the same meaning and interactive treatment
as the corresponding argument to @code{write-file}. @xref{Definition of
HCoop / bpt / emacs.git / blobdiff