onews.3

windows版本的emacs

If this variable is non-`nil', then when Emacs is about to save a
file, it will create the backup file by copying if that would avoid
changing the file's uid or gid.

The default value of this variable is `nil', because usually it is
useful to have the uid of a file change according to who edited it
last.  I recommend thet this variable be left normally `nil' and
changed with a local variables list in those particular files where
the uid needs to be preserved.

** New parameter `file-precious-flag'.

If this variable is non-`nil', saving the buffer tries to avoid
leaving an incomplete file due to disk full or other I/O errors.
It renames the old file before saving.  If saving is successful,
the renamed file is deleted; if saving gets an error, the renamed
file is renamed back to the name you visited.

Backups are always made by copying for such files.

** New variable `buffer-offer-save'.

If the value of this variable is non-`nil' in a buffer then exiting
Emacs will offer to save the buffer (if it is modified and nonempty)
even if the buffer is not visiting a file.  This variable is
automatically made local to the current buffer whenever it is set.

** `rename-file', `copy-file', `add-name-to-file' and `make-symbolic-link'.

The third argument to these functions used to be `t' or `nil'; `t'
meaning go ahead even if the specified new file name already has a file,
and `nil' meaning to get an error.

Now if the third argument is a number it means to ask the user for
confirmation in this case.

** New optional argument to `copy-file'.

If `copy-file' receives a non-nil fourth argument, it attempts
to give the new copy the same time-of-last-modification that the
original file has.

** New function `file-newer-than-file-p'.

(file-newer-than-file-p FILE1 FILE2) returns non-nil if FILE1 has been
modified more recently than FILE2.  If FILE1 does not exist, the value
is always nil; otherwise, if FILE2 does not exist, the value is t.
This is meant for use when FILE2 depends on FILE1, to see if changes
in FILE1 make it necessary to recompute FILE2 from it.

** Changed function `file-exists-p'.

This function is no longer the same as `file-readable-p'.
`file-exists-p' can now return t for a file that exists but which
the fascists won't allow you to read.

** New function `file-locked-p'.

This function receives a file name as argument and returns `nil'
if the file is not locked, `t' if locked by this Emacs, or a
string giving the name of the user who has locked it.

** New function `file-name-sans-versions'.

(file-name-sans-versions NAME) returns a substring of NAME, with any
version numbers or other backup suffixes deleted from the end.

** New functions for directory names.

Although a directory is really a kind of file, specifying a directory
uses a somewhat different syntax from specifying a file.
In Emacs, a directory name is used as part of a file name.

On Unix, the difference is small: a directory name ends in a slash,
while a file name does not: thus, `/usr/rms/' to name a directory,
while `/usr/rms' names the file which holds that directory.

On VMS, the difference is considerable: `du:[rms.foo]' specifies a
directory, but the name of the file that holds that directory is
`du:[rms]foo.dir'.

There are two new functions for converting between directory names
and file names.  `directory-file-name' takes a directory name and
returns the name of the file in which that directory's data is stored.
`file-name-as-directory' takes the name of a file and returns
the corresponding directory name.  These always understand Unix file name
syntax; on VMS, they understand VMS syntax as well.

For example, (file-name-as-directory "/usr/rms") returns "/usr/rms/"
and (directory-file-name "/usr/rms/") returns "/usr/rms".
On VMS, (file-name-as-directory "du:[rms]foo.dir") returns "du:[rms.foo]"
and (directory-file-name "du:[rms.foo]") returns "du:[rms]foo.dir".

** Value of `file-attributes' changed.

The function file-attributes returns a list containing many kinds of
information about a file.  Now the list has eleven elements.

The tenth element is `t' if deleting the file and creating another
file of the same name would result in a change in the file's group;
`nil' if there would be no change.  You can also think of this as
comparing the file's group with the default group for files created in
the same directory by you.

The eleventh element is the inode number of the file.

** VMS-only function `file-name-all-versions'.

This function returns a list of all the completions, including version
number, of a specified version-number-less file name.  This is like
`file-name-all-completions', except that the latter returns values
that do not include version numbers.

** VMS-only variable `vms-stmlf-recfm'.

On a VMS system, if this variable is non-nil, Emacs will give newly
created files the record format `stmlf'.  This is necessary for files
that must contain lines of arbitrary length, such as compiled Emacs
Lisp.

When writing a new version of an existing file, Emacs always keeps
the same record format as the previous version; so this variable has
no effect.

This variable has no effect on Unix systems.

** `insert-file-contents' on an empty file.

This no longer sets the buffer's "modified" flag.

** New function (VMS only) `define-logical-name':

(define-logical-name LOGICAL TRANSLATION) defines a VMS logical name
LOGICAL whose translation is TRANSLATION.  The new name applies to
the current process only.

** Deleted variable `ask-about-buffer-names'.

If you want buffer names for files to be generated in a special way,
you must redefine `create-file-buffer'.

* Subprocess-related changes.

** New function `process-list'.

This function takes no arguments and returns a list of all
of Emacs's asynchronous subprocesses.

** New function `process-exit-status'.

This function, given a process, process name or buffer as argument,
returns the exit status code or signal number of the process.
If the process has not yet exited or died, this function returns 0.

** Process output ignores `buffer-read-only'.

Output from a process will go into the process's buffer even if the
buffer is read only.

** Switching buffers in filter functions and sentinels.

Emacs no longer saves and restore the current buffer around calling
the filter and sentinel functions, so these functions can now
permanently alter the selected buffer in a straightforward manner.

** Specifying environment variables for subprocesses.

When a subprocess is started with `start-process' or `call-process',
the value of the variable `process-environment' is taken to
specify the environment variables to give the subprocess.  The
value should be a list of strings, each of the form "VAR=VALUE".

`process-environment' is initialized when Emacs starts up
based on Emacs's environment.

** New variable `process-connection-type'.

If this variable is `nil', when a subprocess is created, Emacs uses
a pipe rather than a pty to communicate with it.  Normally this
variable is `t', telling Emacs to use a pty if ptys are supported
and one is available.

** New function `waiting-for-user-input-p'.

This function, given a subprocess as argument, returns `t' if that
subprocess appears to be waiting for input sent from Emacs,
or `nil' otherwise.

** New hook `shell-set-directory-error-hook'.

The value of this variable is called, with no arguments, whenever
Shell mode gets an error trying to keep track of directory-setting
commands (such as `cd' and `pushd') used in the shell buffer.

* New functions `user-uid' and `user-real-uid'.

These functions take no arguments and return, respectively,
the effective uid and the real uid of the Emacs process.
The value in each case is an integer.

* New variable `print-escape-newlines' controls string printing.

If this variable is non-`nil', then when a Lisp string is printed
by the Lisp printing function `prin1' or `print', newline characters
are printed as `\n' rather than as a literal newline.

* New function `sysnetunam' on HPUX.

This function takes two arguments, a network address PATH and a
login string LOGIN, and executes the system call `netunam'.
It returns `t' if the call succeeds, otherwise `nil'.

News regarding installation:

* Many `s-...' file names changed.

Many `s-...' files have been renamed.  All periods in such names,
except the ones just before the final `h', have been changed to
hyphens.  Thus, `s-bsd4.2.h' has been renamed to `s-bsd4-2.h'.

This is so a Unix distribution can be moved mechanically to VMS.

* `DOCSTR...' file now called `DOC-...'.

The file of on-line documentation strings, that used to be
`DOCSTR.mm.nn.oo' in this directory, is now called `DOC-mm.nn.oo'.
This is so that it can port to VMS using the standard conventions
for translating filenames for VMS.

This file also now contains the doc strings for variables as
well as functions.

* Emacs no longer uses floating point arithmetic.

This may make it easier to port to some machines.

* Macros `XPNTR' and `XSETPNTR'; flag `DATA_SEG_BITS'.

These macros exclusively are used to unpack a pointer from a Lisp_Object
and to insert a pointer into a Lisp_Object.  Redefining them may help
port Emacs to machines in which all pointers to data objects have
certain high bits set.

If `DATA_SEG_BITS' is defined, it should be a number which contains
the high bits to be inclusive or'ed with pointers that are unpacked.

* New flag `HAVE_X_MENU'.

Define this flag in `config.h' in addition to `HAVE_X_WINDOWS'
to enable use of the Emacs interface to X Menus.  On some operating
systems, the rest of the X interface works properly but X Menus
do not work; hence this separate flag.  See the file `src/xmenu.c'
for more information.

* Macros `ARRAY_MARK_FLAG' and `DONT_COPY_FLAG'.

* `HAVE_ALLOCA' prevents assembly of `alloca.s'.

* `SYSTEM_MALLOC' prevents use of GNU `malloc.c'.

SYSTEM_MALLOC, if defined, means use the system's own `malloc' routines
rather than those that come with Emacs.

Use this only if absolutely necessary, because if it is used you do
not get warnings when space is getting low.

* New flags to control unexec.

See the file `unexec.c' for a long comment on the compilation
switches that suffice to make it work on many machines.

* `PNTR_COMPARISON_TYPE'

Pointers that need to be compared for ordering are converted to this type
first.  Normally this is `unsigned int'.

* `HAVE_VFORK', `HAVE_DUP2' and `HAVE_GETTIMEOFDAY'.

These flags just say whether certain system calls are available.

* New macros control compiler switches, linker switches and libraries.

The m- and s- files can now control in a modular fashion the precise
arguments passed to `cc' and `ld'.

LIBS_STANDARD defines the standard C libraries.  Default is `-lc'.
LIBS_DEBUG defines the extra libraries to use when debugging.  Default `-lg'.
LIBS_SYSTEM can be defined by the s- file to specify extra libraries.
LIBS_MACHINE can be defined by the m- file to specify extra libraries.
LIBS_TERMCAP defines the libraries for Termcap or Terminfo.
  It is defined by default in a complicated fashion but the m- or s- file
  can override it.

LD_SWITCH_SYSTEM can be defined by the s- file to specify extra `ld' switches.
  The default is `-X' on BSD systems except those few that use COFF object files.
LD_SWITCH_MACHINE can be defined by the m- file to specify extra `ld' switches.

C_DEBUG_SWITCH defines the switches to give `cc' when debugging.  Default `-g'.
C_OPTIMIZE_SWITCH defines the switches to give `cc' to optimize.  Default `-O'.
C_SWITCH_MACHINE can be defined by the m- file to specify extra `cc' switches.

For older news, see the file ONEWS.2.

----------------------------------------------------------------------
Copyright information:

Copyright (C) 1988 Free Software Foundation, Inc.

   Permission is granted to anyone to make or distribute verbatim copies
   of this document as received, in any medium, provided that the
   copyright notice and this permission notice are preserved,
   thus giving the recipient permission to redistribute in turn.

   Permission is granted to distribute modified versions
   of this document, or of portions of it,
   under the above conditions, provided also that they
   carry prominent notices stating who last changed them.

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