-\1f
-File: lispref.info, Node: Sentinels, Next: Process Window Size, Prev: Output from Processes, Up: Processes
-
-Sentinels: Detecting Process Status Changes
-===========================================
-
- A "process sentinel" is a function that is called whenever the
-associated process changes status for any reason, including signals
-(whether sent by XEmacs or caused by the process's own actions) that
-terminate, stop, or continue the process. The process sentinel is also
-called if the process exits. The sentinel receives two arguments: the
-process for which the event occurred, and a string describing the type
-of event.
-
- The string describing the event looks like one of the following:
-
- * `"finished\n"'.
-
- * `"exited abnormally with code EXITCODE\n"'.
-
- * `"NAME-OF-SIGNAL\n"'.
-
- * `"NAME-OF-SIGNAL (core dumped)\n"'.
-
- A sentinel runs only while XEmacs is waiting (e.g., for terminal
-input, or for time to elapse, or for process output). This avoids the
-timing errors that could result from running them at random places in
-the middle of other Lisp programs. A program can wait, so that
-sentinels will run, by calling `sit-for' or `sleep-for' (*note
-Waiting::), or `accept-process-output' (*note Accepting Output::).
-Emacs is also waiting when the command loop is reading input.
-
- Quitting is normally inhibited within a sentinel--otherwise, the
-effect of typing `C-g' at command level or to quit a user command would
-be unpredictable. If you want to permit quitting inside a sentinel,
-bind `inhibit-quit' to `nil'. *Note Quitting::.
-
- A sentinel that writes the output into the buffer of the process
-should check whether the buffer is still alive. If it tries to insert
-into a dead buffer, it will get an error. If the buffer is dead,
-`(buffer-name (process-buffer PROCESS))' returns `nil'.
-
- If an error happens during execution of a sentinel, it is caught
-automatically, so that it doesn't stop the execution of whatever
-programs was running when the sentinel was started. However, if
-`debug-on-error' is non-`nil', the error-catching is turned off. This
-makes it possible to use the Lisp debugger to debug the sentinel.
-*Note Debugger::.
-
- In earlier Emacs versions, every sentinel that did regexp searching
-or matching had to explicitly save and restore the match data. Now
-Emacs does this automatically; sentinels never need to do it explicitly.
-*Note Match Data::.
-
- - Function: set-process-sentinel process sentinel
- This function associates SENTINEL with PROCESS. If SENTINEL is
- `nil', then the process will have no sentinel. The default
- behavior when there is no sentinel is to insert a message in the
- process's buffer when the process status changes.
-
- (defun msg-me (process event)
- (princ
- (format "Process: %s had the event `%s'" process event)))
- (set-process-sentinel (get-process "shell") 'msg-me)
- => msg-me
- (kill-process (get-process "shell"))
- -| Process: #<process shell> had the event `killed'
- => #<process shell>
-
- - Function: process-sentinel process
- This function returns the sentinel of PROCESS, or `nil' if it has
- none.
-
- - Function: waiting-for-user-input-p
- While a sentinel or filter function is running, this function
- returns non-`nil' if XEmacs was waiting for keyboard input from
- the user at the time the sentinel or filter function was called,
- `nil' if it was not.
-
-\1f
-File: lispref.info, Node: Process Window Size, Next: Transaction Queues, Prev: Sentinels, Up: Processes
-
-Process Window Size
-===================
-
- - Function: set-process-window-size process height width
- This function tells PROCESS that its logical window size is HEIGHT
- by WIDTH characters. This is principally useful with pty's.
-
-\1f
-File: lispref.info, Node: Transaction Queues, Next: Network, Prev: Process Window Size, Up: Processes
-
-Transaction Queues
-==================
-
- You can use a "transaction queue" for more convenient communication
-with subprocesses using transactions. First use `tq-create' to create
-a transaction queue communicating with a specified process. Then you
-can call `tq-enqueue' to send a transaction.
-
- - Function: tq-create process
- This function creates and returns a transaction queue
- communicating with PROCESS. The argument PROCESS should be a
- subprocess capable of sending and receiving streams of bytes. It
- may be a child process, or it may be a TCP connection to a server,
- possibly on another machine.
-
- - Function: tq-enqueue queue question regexp closure fn
- This function sends a transaction to queue QUEUE. Specifying the
- queue has the effect of specifying the subprocess to talk to.
-
- The argument QUESTION is the outgoing message that starts the
- transaction. The argument FN is the function to call when the
- corresponding answer comes back; it is called with two arguments:
- CLOSURE, and the answer received.
-
- The argument REGEXP is a regular expression that should match the
- entire answer, but nothing less; that's how `tq-enqueue' determines
- where the answer ends.
-
- The return value of `tq-enqueue' itself is not meaningful.
-
- - Function: tq-close queue
- Shut down transaction queue QUEUE, waiting for all pending
- transactions to complete, and then terminate the connection or
- child process.
-
- Transaction queues are implemented by means of a filter function.
-*Note Filter Functions::.
-
-\1f
-File: lispref.info, Node: Network, Prev: Transaction Queues, Up: Processes
-
-Network Connections
-===================
-
- XEmacs Lisp programs can open TCP network connections to other
-processes on the same machine or other machines. A network connection
-is handled by Lisp much like a subprocess, and is represented by a
-process object. However, the process you are communicating with is not
-a child of the XEmacs process, so you can't kill it or send it signals.
-All you can do is send and receive data. `delete-process' closes the
-connection, but does not kill the process at the other end; that
-process must decide what to do about closure of the connection.
-
- You can distinguish process objects representing network connections
-from those representing subprocesses with the `process-status'
-function. It always returns either `open' or `closed' for a network
-connection, and it never returns either of those values for a real
-subprocess. *Note Process Information::.
-
- - Function: open-network-stream name buffer-or-name host service
- This function opens a TCP connection for a service to a host. It
- returns a process object to represent the connection.
-
- The NAME argument specifies the name for the process object. It
- is modified as necessary to make it unique.
-
- The BUFFER-OR-NAME argument is the buffer to associate with the
- connection. Output from the connection is inserted in the buffer,
- unless you specify a filter function to handle the output. If
- BUFFER-OR-NAME is `nil', it means that the connection is not
- associated with any buffer.
-
- The arguments HOST and SERVICE specify where to connect to; HOST
- is the host name or IP address (a string), and SERVICE is the name
- of a defined network service (a string) or a port number (an
- integer).
-
-\1f
-File: lispref.info, Node: System Interface, Next: X-Windows, Prev: Processes, Up: Top
-
-Operating System Interface
-**************************
-
- This chapter is about starting and getting out of Emacs, access to
-values in the operating system environment, and terminal input, output,
-and flow control.
-
- *Note Building XEmacs::, for related information. See also *Note
-Display::, for additional operating system status information
-pertaining to the terminal and the screen.
-
-* Menu:
-
-* Starting Up:: Customizing XEmacs start-up processing.
-* Getting Out:: How exiting works (permanent or temporary).
-* System Environment:: Distinguish the name and kind of system.
-* User Identification:: Finding the name and user id of the user.
-* Time of Day:: Getting the current time.
-* Time Conversion:: Converting a time from numeric form to a string, or
- to calendrical data (or vice versa).
-* Timers:: Setting a timer to call a function at a certain time.
-* Terminal Input:: Recording terminal input for debugging.
-* Terminal Output:: Recording terminal output for debugging.
-* Flow Control:: How to turn output flow control on or off.
-* Batch Mode:: Running XEmacs without terminal interaction.
-
-\1f
-File: lispref.info, Node: Starting Up, Next: Getting Out, Up: System Interface
-
-Starting Up XEmacs
-==================
-
- This section describes what XEmacs does when it is started, and how
-you can customize these actions.
-
-* Menu:
-
-* Start-up Summary:: Sequence of actions XEmacs performs at start-up.
-* Init File:: Details on reading the init file (`.emacs').
-* Terminal-Specific:: How the terminal-specific Lisp file is read.
-* Command Line Arguments:: How command line arguments are processed,
- and how you can customize them.
-
-\1f
-File: lispref.info, Node: Start-up Summary, Next: Init File, Up: Starting Up
-
-Summary: Sequence of Actions at Start Up
-----------------------------------------
-
- The order of operations performed (in `startup.el') by XEmacs when
-it is started up is as follows:
-
- 1. It loads the initialization library for the window system, if you
- are using a window system. This library's name is
- `term/WINDOWSYSTEM-win.el'.
-
- 2. It processes the initial options. (Some of them are handled even
- earlier than this.)
-
- 3. It initializes the X window frame and faces, if appropriate.
-
- 4. It runs the normal hook `before-init-hook'.
-
- 5. It loads the library `site-start', unless the option
- `-no-site-file' was specified. The library's file name is usually
- `site-start.el'.
-
- 6. It loads the file `~/.emacs' unless `-q' was specified on the
- command line. (This is not done in `-batch' mode.) The `-u'
- option can specify the user name whose home directory should be
- used instead of `~'.
-
- 7. It loads the library `default' unless `inhibit-default-init' is
- non-`nil'. (This is not done in `-batch' mode or if `-q' was
- specified on the command line.) The library's file name is
- usually `default.el'.
-
- 8. It runs the normal hook `after-init-hook'.
-
- 9. It sets the major mode according to `initial-major-mode', provided
- the buffer `*scratch*' is still current and still in Fundamental
- mode.
-
- 10. It loads the terminal-specific Lisp file, if any, except when in
- batch mode or using a window system.
-
- 11. It displays the initial echo area message, unless you have
- suppressed that with `inhibit-startup-echo-area-message'.
-
- 12. It processes the action arguments from the command line.
-
- 13. It runs `term-setup-hook'.
-
- 14. It calls `frame-notice-user-settings', which modifies the
- parameters of the selected frame according to whatever the init
- files specify.
-
- 15. It runs `window-setup-hook'. *Note Terminal-Specific::.
-
- 16. It displays copyleft, nonwarranty, and basic use information,
- provided there were no remaining command line arguments (a few
- steps above) and the value of `inhibit-startup-message' is `nil'.
-
- - User Option: inhibit-startup-message
- This variable inhibits the initial startup messages (the
- nonwarranty, etc.). If it is non-`nil', then the messages are not
- printed.
-
- This variable exists so you can set it in your personal init file,
- once you are familiar with the contents of the startup message.
- Do not set this variable in the init file of a new user, or in a
- way that affects more than one user, because that would prevent
- new users from receiving the information they are supposed to see.
-
- - User Option: inhibit-startup-echo-area-message
- This variable controls the display of the startup echo area
- message. You can suppress the startup echo area message by adding
- text with this form to your `.emacs' file:
-
- (setq inhibit-startup-echo-area-message
- "YOUR-LOGIN-NAME")
-
- Simply setting `inhibit-startup-echo-area-message' to your login
- name is not sufficient to inhibit the message; Emacs explicitly
- checks whether `.emacs' contains an expression as shown above.
- Your login name must appear in the expression as a Lisp string
- constant.
-
- This way, you can easily inhibit the message for yourself if you
- wish, but thoughtless copying of your `.emacs' file will not
- inhibit the message for someone else.
-
-\1f
-File: lispref.info, Node: Init File, Next: Terminal-Specific, Prev: Start-up Summary, Up: Starting Up
-
-The Init File: `.emacs'
------------------------
-
- When you start XEmacs, it normally attempts to load the file
-`.emacs' from your home directory. This file, if it exists, must
-contain Lisp code. It is called your "init file". The command line
-switches `-q' and `-u' affect the use of the init file; `-q' says not
-to load an init file, and `-u' says to load a specified user's init
-file instead of yours. *Note Entering XEmacs: (xemacs)Entering XEmacs.
-
- A site may have a "default init file", which is the library named
-`default.el'. XEmacs finds the `default.el' file through the standard
-search path for libraries (*note How Programs Do Loading::). The
-XEmacs distribution does not come with this file; sites may provide one
-for local customizations. If the default init file exists, it is
-loaded whenever you start Emacs, except in batch mode or if `-q' is
-specified. But your own personal init file, if any, is loaded first; if
-it sets `inhibit-default-init' to a non-`nil' value, then XEmacs does
-not subsequently load the `default.el' file.
-
- Another file for site-customization is `site-start.el'. Emacs loads
-this _before_ the user's init file. You can inhibit the loading of
-this file with the option `-no-site-file'.
-
- - Variable: site-run-file
- This variable specifies the site-customization file to load before
- the user's init file. Its normal value is `"site-start"'.
-
- If there is a great deal of code in your `.emacs' file, you should
-move it into another file named `SOMETHING.el', byte-compile it (*note
-Byte Compilation::), and make your `.emacs' file load the other file
-using `load' (*note Loading::).
-
- *Note Init File Examples: (xemacs)Init File Examples, for examples
-of how to make various commonly desired customizations in your `.emacs'
-file.
-
- - User Option: inhibit-default-init
- This variable prevents XEmacs from loading the default
- initialization library file for your session of XEmacs. If its
- value is non-`nil', then the default library is not loaded. The
- default value is `nil'.
-
- - Variable: before-init-hook
- - Variable: after-init-hook
- These two normal hooks are run just before, and just after,
- loading of the user's init file, `default.el', and/or
- `site-start.el'.
-
-\1f
-File: lispref.info, Node: Terminal-Specific, Next: Command Line Arguments, Prev: Init File, Up: Starting Up
-
-Terminal-Specific Initialization
---------------------------------
-
- Each terminal type can have its own Lisp library that XEmacs loads
-when run on that type of terminal. For a terminal type named TERMTYPE,
-the library is called `term/TERMTYPE'. XEmacs finds the file by
-searching the `load-path' directories as it does for other files, and
-trying the `.elc' and `.el' suffixes. Normally, terminal-specific Lisp
-library is located in `emacs/lisp/term', a subdirectory of the
-`emacs/lisp' directory in which most XEmacs Lisp libraries are kept.
-
- The library's name is constructed by concatenating the value of the
-variable `term-file-prefix' and the terminal type. Normally,
-`term-file-prefix' has the value `"term/"'; changing this is not
-recommended.
-
- The usual function of a terminal-specific library is to enable
-special keys to send sequences that XEmacs can recognize. It may also
-need to set or add to `function-key-map' if the Termcap entry does not
-specify all the terminal's function keys. *Note Terminal Input::.
-
- When the name of the terminal type contains a hyphen, only the part
-of the name before the first hyphen is significant in choosing the
-library name. Thus, terminal types `aaa-48' and `aaa-30-rv' both use
-the `term/aaa' library. If necessary, the library can evaluate
-`(getenv "TERM")' to find the full name of the terminal type.
-
- Your `.emacs' file can prevent the loading of the terminal-specific
-library by setting the variable `term-file-prefix' to `nil'. This
-feature is useful when experimenting with your own peculiar
-customizations.
-
- You can also arrange to override some of the actions of the
-terminal-specific library by setting the variable `term-setup-hook'.
-This is a normal hook which XEmacs runs using `run-hooks' at the end of
-XEmacs initialization, after loading both your `.emacs' file and any
-terminal-specific libraries. You can use this variable to define
-initializations for terminals that do not have their own libraries.
-*Note Hooks::.
-
- - Variable: term-file-prefix
- If the `term-file-prefix' variable is non-`nil', XEmacs loads a
- terminal-specific initialization file as follows:
-
- (load (concat term-file-prefix (getenv "TERM")))
-
- You may set the `term-file-prefix' variable to `nil' in your
- `.emacs' file if you do not wish to load the
- terminal-initialization file. To do this, put the following in
- your `.emacs' file: `(setq term-file-prefix nil)'.
-
- - Variable: term-setup-hook
- This variable is a normal hook that XEmacs runs after loading your
- `.emacs' file, the default initialization file (if any) and the
- terminal-specific Lisp file.
-
- You can use `term-setup-hook' to override the definitions made by a
- terminal-specific file.
-
- - Variable: window-setup-hook
- This variable is a normal hook which XEmacs runs after loading your
- `.emacs' file and the default initialization file (if any), after
- loading terminal-specific Lisp code, and after running the hook
- `term-setup-hook'.
-
-\1f
-File: lispref.info, Node: Command Line Arguments, Prev: Terminal-Specific, Up: Starting Up
-
-Command Line Arguments
-----------------------
-
- You can use command line arguments to request various actions when
-you start XEmacs. Since you do not need to start XEmacs more than once
-per day, and will often leave your XEmacs session running longer than
-that, command line arguments are hardly ever used. As a practical
-matter, it is best to avoid making the habit of using them, since this
-habit would encourage you to kill and restart XEmacs unnecessarily
-often. These options exist for two reasons: to be compatible with
-other editors (for invocation by other programs) and to enable shell
-scripts to run specific Lisp programs.
-
- This section describes how Emacs processes command line arguments,
-and how you can customize them.
-
- - Function: command-line
- This function parses the command line that XEmacs was called with,
- processes it, loads the user's `.emacs' file and displays the
- startup messages.
-
- - Variable: command-line-processed
- The value of this variable is `t' once the command line has been
- processed.
-
- If you redump XEmacs by calling `dump-emacs', you may wish to set
- this variable to `nil' first in order to cause the new dumped
- XEmacs to process its new command line arguments.
-
- - Variable: command-switch-alist
- The value of this variable is an alist of user-defined command-line
- options and associated handler functions. This variable exists so
- you can add elements to it.
-
- A "command line option" is an argument on the command line of the
- form:
-
- -OPTION
-
- The elements of the `command-switch-alist' look like this:
-
- (OPTION . HANDLER-FUNCTION)
-
- The HANDLER-FUNCTION is called to handle OPTION and receives the
- option name as its sole argument.
-
- In some cases, the option is followed in the command line by an
- argument. In these cases, the HANDLER-FUNCTION can find all the
- remaining command-line arguments in the variable
- `command-line-args-left'. (The entire list of command-line
- arguments is in `command-line-args'.)
-
- The command line arguments are parsed by the `command-line-1'
- function in the `startup.el' file. See also *Note Command Line
- Switches and Arguments: (xemacs)Command Switches.
-
- - Variable: command-line-args
- The value of this variable is the list of command line arguments
- passed to XEmacs.
-
- - Variable: command-line-functions
- This variable's value is a list of functions for handling an
- unrecognized command-line argument. Each time the next argument
- to be processed has no special meaning, the functions in this list
- are called, in order of appearance, until one of them returns a
- non-`nil' value.
-
- These functions are called with no arguments. They can access the
- command-line argument under consideration through the variable
- `argi'. The remaining arguments (not including the current one)
- are in the variable `command-line-args-left'.
-
- When a function recognizes and processes the argument in `argi', it
- should return a non-`nil' value to say it has dealt with that
- argument. If it has also dealt with some of the following
- arguments, it can indicate that by deleting them from
- `command-line-args-left'.
-
- If all of these functions return `nil', then the argument is used
- as a file name to visit.
-
-\1f
-File: lispref.info, Node: Getting Out, Next: System Environment, Prev: Starting Up, Up: System Interface
-
-Getting out of XEmacs
-=====================
-
- There are two ways to get out of XEmacs: you can kill the XEmacs job,
-which exits permanently, or you can suspend it, which permits you to
-reenter the XEmacs process later. As a practical matter, you seldom
-kill XEmacs--only when you are about to log out. Suspending is much
-more common.
-
-* Menu:
-
-* Killing XEmacs:: Exiting XEmacs irreversibly.
-* Suspending XEmacs:: Exiting XEmacs reversibly.
-
-\1f
-File: lispref.info, Node: Killing XEmacs, Next: Suspending XEmacs, Up: Getting Out
-
-Killing XEmacs
---------------
-
- Killing XEmacs means ending the execution of the XEmacs process. The
-parent process normally resumes control. The low-level primitive for
-killing XEmacs is `kill-emacs'.
-
- - Function: kill-emacs &optional exit-data
- This function exits the XEmacs process and kills it.
-
- If EXIT-DATA is an integer, then it is used as the exit status of
- the XEmacs process. (This is useful primarily in batch operation;
- see *Note Batch Mode::.)
-
- If EXIT-DATA is a string, its contents are stuffed into the
- terminal input buffer so that the shell (or whatever program next
- reads input) can read them.
-
- All the information in the XEmacs process, aside from files that have
-been saved, is lost when the XEmacs is killed. Because killing XEmacs
-inadvertently can lose a lot of work, XEmacs queries for confirmation
-before actually terminating if you have buffers that need saving or
-subprocesses that are running. This is done in the function
-`save-buffers-kill-emacs'.
-
- - Variable: kill-emacs-query-functions
- After asking the standard questions, `save-buffers-kill-emacs'
- calls the functions in the list `kill-buffer-query-functions', in
- order of appearance, with no arguments. These functions can ask
- for additional confirmation from the user. If any of them returns
- non-`nil', XEmacs is not killed.
-
- - Variable: kill-emacs-hook
- This variable is a normal hook; once `save-buffers-kill-emacs' is
- finished with all file saving and confirmation, it runs the
- functions in this hook.
-
-\1f
-File: lispref.info, Node: Suspending XEmacs, Prev: Killing XEmacs, Up: Getting Out
-
-Suspending XEmacs
------------------
-
- "Suspending XEmacs" means stopping XEmacs temporarily and returning
-control to its superior process, which is usually the shell. This
-allows you to resume editing later in the same XEmacs process, with the
-same buffers, the same kill ring, the same undo history, and so on. To
-resume XEmacs, use the appropriate command in the parent shell--most
-likely `fg'.
-
- Some operating systems do not support suspension of jobs; on these
-systems, "suspension" actually creates a new shell temporarily as a
-subprocess of XEmacs. Then you would exit the shell to return to
-XEmacs.
-
- Suspension is not useful with window systems such as X, because the
-XEmacs job may not have a parent that can resume it again, and in any
-case you can give input to some other job such as a shell merely by
-moving to a different window. Therefore, suspending is not allowed
-when XEmacs is an X client.
-
- - Function: suspend-emacs string
- This function stops XEmacs and returns control to the superior
- process. If and when the superior process resumes XEmacs,
- `suspend-emacs' returns `nil' to its caller in Lisp.
-
- If STRING is non-`nil', its characters are sent to be read as
- terminal input by XEmacs's superior shell. The characters in
- STRING are not echoed by the superior shell; only the results
- appear.
-
- Before suspending, `suspend-emacs' runs the normal hook
- `suspend-hook'. In Emacs version 18, `suspend-hook' was not a
- normal hook; its value was a single function, and if its value was
- non-`nil', then `suspend-emacs' returned immediately without
- actually suspending anything.
-
- After the user resumes XEmacs, `suspend-emacs' runs the normal hook
- `suspend-resume-hook'. *Note Hooks::.
-
- The next redisplay after resumption will redraw the entire screen,
- unless the variable `no-redraw-on-reenter' is non-`nil' (*note
- Refresh Screen::).
-
- In the following example, note that `pwd' is not echoed after
- XEmacs is suspended. But it is read and executed by the shell.
-
- (suspend-emacs)
- => nil
-
- (add-hook 'suspend-hook
- (function (lambda ()
- (or (y-or-n-p
- "Really suspend? ")
- (error "Suspend cancelled")))))
- => (lambda nil
- (or (y-or-n-p "Really suspend? ")
- (error "Suspend cancelled")))
- (add-hook 'suspend-resume-hook
- (function (lambda () (message "Resumed!"))))
- => (lambda nil (message "Resumed!"))
- (suspend-emacs "pwd")
- => nil
- ---------- Buffer: Minibuffer ----------
- Really suspend? y
- ---------- Buffer: Minibuffer ----------
-
- ---------- Parent Shell ----------
- lewis@slug[23] % /user/lewis/manual
- lewis@slug[24] % fg
-
- ---------- Echo Area ----------
- Resumed!
-
- - Variable: suspend-hook
- This variable is a normal hook run before suspending.
-
- - Variable: suspend-resume-hook
- This variable is a normal hook run after suspending.
-
-\1f
-File: lispref.info, Node: System Environment, Next: User Identification, Prev: Getting Out, Up: System Interface
-
-Operating System Environment
-============================
-
- XEmacs provides access to variables in the operating system
-environment through various functions. These variables include the
-name of the system, the user's UID, and so on.
-
- - Variable: system-type
- The value of this variable is a symbol indicating the type of
- operating system XEmacs is operating on. Here is a table of the
- possible values:
-
- `aix-v3'
- AIX.
-
- `berkeley-unix'
- Berkeley BSD.
-
- `dgux'
- Data General DGUX operating system.
-
- `gnu'
- A GNU system using the GNU HURD and Mach.
-
- `hpux'
- Hewlett-Packard HPUX operating system.
-
- `irix'
- Silicon Graphics Irix system.
-
- `linux'
- A GNU system using the Linux kernel.
-
- `ms-dos'
- Microsoft MS-DOS "operating system."
-
- `next-mach'
- NeXT Mach-based system.
-
- `rtu'
- Masscomp RTU, UCB universe.
-
- `unisoft-unix'
- UniSoft UniPlus.
-
- `usg-unix-v'
- AT&T System V.
-
- `vax-vms'
- VAX VMS.
-
- `windows-nt'
- Microsoft windows NT.
-
- `xenix'
- SCO Xenix 386.
-
- We do not wish to add new symbols to make finer distinctions
- unless it is absolutely necessary! In fact, we hope to eliminate
- some of these alternatives in the future. We recommend using
- `system-configuration' to distinguish between different operating
- systems.
-
- - Variable: system-configuration
- This variable holds the three-part configuration name for the
- hardware/software configuration of your system, as a string. The
- convenient way to test parts of this string is with `string-match'.
-
- - Function: system-name
- This function returns the name of the machine you are running on.
- (system-name)
- => "prep.ai.mit.edu"
-
- The symbol `system-name' is a variable as well as a function. In
-fact, the function returns whatever value the variable `system-name'
-currently holds. Thus, you can set the variable `system-name' in case
-Emacs is confused about the name of your system. The variable is also
-useful for constructing frame titles (*note Frame Titles::).
-
- - Variable: mail-host-address
- If this variable is non-`nil', it is used instead of `system-name'
- for purposes of generating email addresses. For example, it is
- used when constructing the default value of `user-mail-address'.
- *Note User Identification::. (Since this is done when XEmacs
- starts up, the value actually used is the one saved when XEmacs
- was dumped. *Note Building XEmacs::.)
-
- - Function: getenv var
- This function returns the value of the environment variable VAR,
- as a string. Within XEmacs, the environment variable values are
- kept in the Lisp variable `process-environment'.
-
- (getenv "USER")
- => "lewis"
-
- lewis@slug[10] % printenv
- PATH=.:/user/lewis/bin:/usr/bin:/usr/local/bin
- USER=lewis
- TERM=ibmapa16
- SHELL=/bin/csh
- HOME=/user/lewis
-
- - Command: setenv variable value
- This command sets the value of the environment variable named
- VARIABLE to VALUE. Both arguments should be strings. This
- function works by modifying `process-environment'; binding that
- variable with `let' is also reasonable practice.
-
- - Variable: process-environment
- This variable is a list of strings, each describing one environment
- variable. The functions `getenv' and `setenv' work by means of
- this variable.
-
- process-environment
- => ("l=/usr/stanford/lib/gnuemacs/lisp"
- "PATH=.:/user/lewis/bin:/usr/class:/nfsusr/local/bin"
- "USER=lewis"
- "TERM=ibmapa16"
- "SHELL=/bin/csh"
- "HOME=/user/lewis")
-
- - Variable: path-separator
- This variable holds a string which says which character separates
- directories in a search path (as found in an environment
- variable). Its value is `":"' for Unix and GNU systems, and `";"'
- for MS-DOS and Windows NT.
-
- - Variable: invocation-name
- This variable holds the program name under which Emacs was
- invoked. The value is a string, and does not include a directory
- name.
-
- - Variable: invocation-directory
- This variable holds the directory from which the Emacs executable
- was invoked, or perhaps `nil' if that directory cannot be
- determined.
-
- - Variable: installation-directory
- If non-`nil', this is a directory within which to look for the
- `lib-src' and `etc' subdirectories. This is non-`nil' when Emacs
- can't find those directories in their standard installed
- locations, but can find them in a directory related somehow to the
- one containing the Emacs executable.
-
- - Function: load-average &optional use-floats
- This function returns a list of the current 1-minute, 5-minute and
- 15-minute load averages. The values are integers that are 100
- times the system load averages. (The load averages indicate the
- number of processes trying to run.)
-
- When USE-FLOATS is non-`nil', floats will be returned instead of
- integers. These floats are not multiplied by 100.
-
- (load-average)
- => (169 158 164)
- (load-average t)
- => (1.69921875 1.58984375 1.640625)
-
- lewis@rocky[5] % uptime
- 8:06pm up 16 day(s), 21:57, 40 users,
- load average: 1.68, 1.59, 1.64
-
- If the 5-minute or 15-minute load averages are not available,
- return a shortened list, containing only those averages which are
- available.
-
- On some systems, this function may require special privileges to
- run, or it may be unimplemented for the particular system type.
- In that case, the function will signal an error.
-
- - Function: emacs-pid
- This function returns the process ID of the Emacs process.
-
- - Function: setprv privilege-name &optional setp getprv
- This function sets or resets a VMS privilege. (It does not exist
- on Unix.) The first arg is the privilege name, as a string. The
- second argument, SETP, is `t' or `nil', indicating whether the
- privilege is to be turned on or off. Its default is `nil'. The
- function returns `t' if successful, `nil' otherwise.
-
- If the third argument, GETPRV, is non-`nil', `setprv' does not
- change the privilege, but returns `t' or `nil' indicating whether
- the privilege is currently enabled.
-
-\1f
-File: lispref.info, Node: User Identification, Next: Time of Day, Prev: System Environment, Up: System Interface
-
-User Identification
-===================
-
- - Variable: user-mail-address
- This holds the nominal email address of the user who is using
- Emacs. When Emacs starts up, it computes a default value that is
- usually right, but users often set this themselves when the
- default value is not right.
-
- - Function: user-login-name &optional uid
- If you don't specify UID, this function returns the name under
- which the user is logged in. If the environment variable `LOGNAME'
- is set, that value is used. Otherwise, if the environment variable
- `USER' is set, that value is used. Otherwise, the value is based
- on the effective UID, not the real UID.
-
- If you specify UID, the value is the user name that corresponds to
- UID (which should be an integer).
-
- (user-login-name)
- => "lewis"
-
- - Function: user-real-login-name
- This function returns the user name corresponding to Emacs's real
- UID. This ignores the effective UID and ignores the environment
- variables `LOGNAME' and `USER'.
-
- - Variable: user-full-name
- This variable holds the name of the user running this Emacs. It is
- initialized at startup time from the value of `NAME' environment
- variable. You can change the value of this variable to alter the
- result of the `user-full-name' function.
-
- - Function: user-full-name &optional user
- This function returns the full name of USER. If USER is `nil', it
- defaults to the user running this Emacs. In that case, the value
- of `user-full-name' variable, if non-`nil', will be used.
-
- If USER is specified explicitly, `user-full-name' variable is
- ignored.
-
- (user-full-name)
- => "Hrvoje Niksic"
- (setq user-full-name "Hrvoje \"Niksa\" Niksic")
- (user-full-name)
- => "Hrvoje \"Niksa\" Niksic"
- (user-full-name "hniksic")
- => "Hrvoje Niksic"
-
- The symbols `user-login-name', `user-real-login-name' and
-`user-full-name' are variables as well as functions. The functions
-return the same values that the variables hold. These variables allow
-you to "fake out" Emacs by telling the functions what to return. The
-variables are also useful for constructing frame titles (*note Frame
-Titles::).
-
- - Function: user-real-uid
- This function returns the real UID of the user.
-
- (user-real-uid)
- => 19
-
- - Function: user-uid
- This function returns the effective UID of the user.
-
- - Function: user-home-directory
- This function returns the "`HOME'" directory of the user, and is
- intended to replace occurrences of "`(getenv "HOME")'". Under
- Unix systems, the following is done:
-
- 1. Return the value of "`(getenv "HOME")'", if set.
-
- 2. Return "/", as a fallback, but issue a warning. (Future
- versions of XEmacs will also attempt to lookup the `HOME'
- directory via `getpwent()', but this has not yet been
- implemented.)
-
- Under MS Windows, this is done:
-
- 1. Return the value of "`(getenv "HOME")'", if set.
-
- 2. If the environment variables `HOMEDRIVE' and `HOMEDIR' are
- both set, return the concatenation (the following description
- uses MS Windows environment variable substitution syntax):
- `%HOMEDRIVE%%HOMEDIR%'.
-
- 3. Return "C:\", as a fallback, but issue a warning.
-