diff options
Diffstat (limited to 'lispref')
| -rw-r--r-- | lispref/files.texi | 92 |
1 files changed, 78 insertions, 14 deletions
diff --git a/lispref/files.texi b/lispref/files.texi index 8665cfbdec3..8b93faf9b68 100644 --- a/lispref/files.texi +++ b/lispref/files.texi @@ -392,6 +392,17 @@ doesn't add newlines at all. @code{nil} is the default value, but a few major modes set it to @code{t} in particular buffers. @end defopt +@deffn Command set-visited-file-name filename &optional no-query +This function changes the visited file name of the current buffer to +@var{filename}. It also renames the buffer based on @var{filename}, +appending a string like @samp{<2>} if necessary to make a unique buffer +name. It marks the buffer as @emph{modified},a since the contents do not +(as far as Emacs knows) match the actual file's contents. + +If the specified file already exists, @code{set-visited-file-name} +asks for confirmation unless @var{no-query} is non-@code{nil}. +@end deffn + @node Reading from Files @comment node-name, next, previous, up @section Reading from Files @@ -1234,6 +1245,8 @@ as well as Unix syntax. * File Name Expansion:: Converting relative file names to absolute ones. * Unique File Names:: Generating names for temporary files. * File Name Completion:: Finding the completions for a given file name. +* Standard File Names:: If your package uses a fixed file name, + how to handle various operating systems simply. @end menu @node File Name Components @@ -1738,6 +1751,53 @@ completion-ignored-extensions @end example @end defopt +@node Standard File Names +@subsection Standard File Names + + Most of the file names used in Lisp programs are entered by the user. +But occasionally a Lisp program needs to specify a standard file name +for a particular use---typically, to hold customization information +about each user. For example, abbrev definitions are stored (by +default) in the file @file{~/.abbrev_defs}; the @code{completion} +package stores completions in the file @file{~/.completions}. These are +two of the many standard file names used by parts of Emacs for certain +purposes. + + Various operating systems have their own conventions for valid file +names and for which file names to use for user profile data. A Lisp +program which reads a file using a standard file name ought to use, on +each type of system, a file name suitable for that system. The function +@code{convert-standard-filename} makes this easy to do. + +@defun convert-standard-filename filename +This function alters the file name @var{filename} to fit the conventions +of the operating system in use, and returns the result as a new string. +@end defun + + The recommended way to specify a standard file name in a Lisp program +is to choose a name which fits the conventions of GNU and Unix systems, +usually with a nondirectory part that starts with a period, and pass it +to @code{convert-standard-filename} instead of using it directly. Here +is an example from the @code{completion} package: + +@example +(defvar save-completions-file-name + (convert-standard-filename "~/.completions") + "*The file name to save completions to.") +@end example + + On GNU and Unix systems, and on some other systems as well, +@code{convert-standard-filename} returns its argument unchanged. On +some other systems, it alters the name to fit the systems's conventions. + + For example, on MS-DOS the alterations made by this function include +converting a leading @samp{.} to @samp{_}, converting a @samp{_} in the +middle of the name to @samp{.} if there is no other @samp{.}, inserting +a @samp{.} after eight characters if there is none, and truncating to +three characters after the @samp{.}. (It makes other changes as well.) +Thus, @file{.abbrev_defs} becomes @file{_abbrev.def}, and +@file{.completions} becomes @file{_complet.ion}. + @node Contents of Directories @section Contents of Directories @cindex directory-oriented functions @@ -1884,7 +1944,7 @@ Here are the operations that a magic file name handler gets to handle: @code{delete-file},@* @code{diff-latest-backup-file}, @code{directory-file-name}, -@code{directory-files}, +@code{directory-files}, @code{dired-call-process}, @code{dired-compress-file}, @code{dired-uncache}, @code{expand-file-name},@* @code{file-accessible-directory-p}, @@ -1894,13 +1954,16 @@ Here are the operations that a magic file name handler gets to handle: @code{file-name-as-directory}, @code{file-name-completion}, @code{file-name-directory}, @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-symlink-p}, @code{file-truename}, @code{file-writable-p}, +@code{find-backup-file-name}, @code{get-file-buffer}, -@code{insert-directory}, -@code{insert-file-contents}, @code{load}, @code{make-directory}, +@code{insert-directory}, @code{insert-file-contents}, +@code{load}, @code{make-directory}, @code{make-symbolic-link}, @code{rename-file}, @code{set-file-modes}, -@code{set-visited-file-modtime}, @code{unhandled-file-name-directory}, +@code{set-visited-file-modtime}, @code{shell-command}. +@code{unhandled-file-name-directory}, @code{vc-registered}, @code{verify-visited-file-modtime}, @code{write-region}. Handlers for @code{insert-file-contents} typically need to clear the @@ -2133,16 +2196,17 @@ is always local in all buffers. @cindex file types on MS-DOS @cindex text files and binary files @cindex binary files and text files - - Emacs on MS-DOS makes a distinction between text files and binary -files. This is necessary because ordinary text files on MS-DOS use a -two character sequence between lines: carriage-return and linefeed -(@sc{crlf}). Emacs expects just a newline character (a linefeed) between -lines. When Emacs reads or writes a text file on MS-DOS, it needs to -convert the line separators. This means it needs to know which files -are text files and which are binary. It makes this decision when -visiting a file, and records the decision in the variable -@code{buffer-file-type} for use when the file is saved. +@cindex Windows file types + + Emacs on MS-DOS and on Windows NT or 95 makes a distinction between +text files and binary files. This is necessary because ordinary text +files on MS-DOS use a two character sequence between lines: +carriage-return and linefeed (@sc{crlf}). Emacs expects just a newline +character (a linefeed) between lines. When Emacs reads or writes a text +file on MS-DOS, it needs to convert the line separators. This means it +needs to know which files are text files and which are binary. It makes +this decision when visiting a file, and records the decision in the +variable @code{buffer-file-type} for use when the file is saved. @xref{MS-DOS Subprocesses}, for a related feature for subprocesses. |