This is Info file ../../info/lispref.info, produced by Makeinfo version 1.68 from the input file lispref.texi. Edition History: GNU Emacs Lisp Reference Manual Second Edition (v2.01), May 1993 GNU Emacs Lisp Reference Manual Further Revised (v2.02), August 1993 Lucid Emacs Lisp Reference Manual (for 19.10) First Edition, March 1994 XEmacs Lisp Programmer's Manual (for 19.12) Second Edition, April 1995 GNU Emacs Lisp Reference Manual v2.4, June 1995 XEmacs Lisp Programmer's Manual (for 19.13) Third Edition, July 1995 XEmacs Lisp Reference Manual (for 19.14 and 20.0) v3.1, March 1996 XEmacs Lisp Reference Manual (for 19.15 and 20.1, 20.2) v3.2, April, May 1997 Copyright (C) 1990, 1991, 1992, 1993, 1994, 1995 Free Software Foundation, Inc. Copyright (C) 1994, 1995 Sun Microsystems, Inc. Copyright (C) 1995, 1996 Ben Wing. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the Foundation. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the section entitled "GNU General Public License" is included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the section entitled "GNU General Public License" may be included in a translation approved by the Free Software Foundation instead of in the original English.  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.  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.  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.  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 This function returns the current 1-minute, 5-minute and 15-minute load averages in a list. The values are integers that are 100 times the system load averages. (The load averages indicate the number of processes trying to run.) (load-average) => (169 48 36) lewis@rocky[5] % uptime 11:55am up 1 day, 19:37, 3 users, load average: 1.69, 0.48, 0.36 - 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.  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'. - Function: user-full-name This function returns the full name of the user. (user-full-name) => "Bil Lewis" 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.  File: lispref.info, Node: Time of Day, Next: Time Conversion, Prev: User Identification, Up: System Interface Time of Day =========== This section explains how to determine the current time and the time zone. - Function: current-time-string &optional TIME-VALUE This function returns the current time and date as a humanly-readable string. The format of the string is unvarying; the number of characters used for each part is always the same, so you can reliably use `substring' to extract pieces of it. It is wise to count the characters from the beginning of the string rather than from the end, as additional information may be added at the end. The argument TIME-VALUE, if given, specifies a time to format instead of the current time. The argument should be a list whose first two elements are integers. Thus, you can use times obtained from `current-time' (see below) and from `file-attributes' (*note File Attributes::.). (current-time-string) => "Wed Oct 14 22:21:05 1987" - Function: current-time This function returns the system's time value as a list of three integers: `(HIGH LOW MICROSEC)'. The integers HIGH and LOW combine to give the number of seconds since 0:00 January 1, 1970, which is HIGH * 2**16 + LOW. The third element, MICROSEC, gives the microseconds since the start of the current second (or 0 for systems that return time only on the resolution of a second). The first two elements can be compared with file time values such as you get with the function `file-attributes'. *Note File Attributes::. - Function: current-time-zone &optional TIME-VALUE This function returns a list describing the time zone that the user is in. The value has the form `(OFFSET NAME)'. Here OFFSET is an integer giving the number of seconds ahead of UTC (east of Greenwich). A negative value means west of Greenwich. The second element, NAME is a string giving the name of the time zone. Both elements change when daylight savings time begins or ends; if the user has specified a time zone that does not use a seasonal time adjustment, then the value is constant through time. If the operating system doesn't supply all the information necessary to compute the value, both elements of the list are `nil'. The argument TIME-VALUE, if given, specifies a time to analyze instead of the current time. The argument should be a cons cell containing two integers, or a list whose first two elements are integers. Thus, you can use times obtained from `current-time' (see above) and from `file-attributes' (*note File Attributes::.).  File: lispref.info, Node: Time Conversion, Next: Timers, Prev: Time of Day, Up: System Interface Time Conversion =============== These functions convert time values (lists of two or three integers) to strings or to calendrical information. There is also a function to convert calendrical information to a time value. You can get time values from the functions `current-time' (*note Time of Day::.) and `file-attributes' (*note File Attributes::.). - Function: format-time-string FORMAT-STRING TIME This function converts TIME to a string according to FORMAT-STRING. The argument FORMAT-STRING may contain `%'-sequences which say to substitute parts of the time. Here is a table of what the `%'-sequences mean: `%a' This stands for the abbreviated name of the day of week. `%A' This stands for the full name of the day of week. `%b' This stands for the abbreviated name of the month. `%B' This stands for the full name of the month. `%c' This is a synonym for `%x %X'. `%C' This has a locale-specific meaning. In the default locale (named C), it is equivalent to `%A, %B %e, %Y'. `%d' This stands for the day of month, zero-padded. `%D' This is a synonym for `%m/%d/%y'. `%e' This stands for the day of month, blank-padded. `%h' This is a synonym for `%b'. `%H' This stands for the hour (00-23). `%I' This stands for the hour (00-12). `%j' This stands for the day of the year (001-366). `%k' This stands for the hour (0-23), blank padded. `%l' This stands for the hour (1-12), blank padded. `%m' This stands for the month (01-12). `%M' This stands for the minute (00-59). `%n' This stands for a newline. `%p' This stands for `AM' or `PM', as appropriate. `%r' This is a synonym for `%I:%M:%S %p'. `%R' This is a synonym for `%H:%M'. `%S' This stands for the seconds (00-60). `%t' This stands for a tab character. `%T' This is a synonym for `%H:%M:%S'. `%U' This stands for the week of the year (01-52), assuming that weeks start on Sunday. `%w' This stands for the numeric day of week (0-6). Sunday is day 0. `%W' This stands for the week of the year (01-52), assuming that weeks start on Monday. `%x' This has a locale-specific meaning. In the default locale (named C), it is equivalent to `%D'. `%X' This has a locale-specific meaning. In the default locale (named C), it is equivalent to `%T'. `%y' This stands for the year without century (00-99). `%Y' This stands for the year with century. `%Z' This stands for the time zone abbreviation. - Function: decode-time TIME This function converts a time value into calendrical information. The return value is a list of nine elements, as follows: (SECONDS MINUTES HOUR DAY MONTH YEAR DOW DST ZONE) Here is what the elements mean: SEC The number of seconds past the minute, as an integer between 0 and 59. MINUTE The number of minutes past the hour, as an integer between 0 and 59. HOUR The hour of the day, as an integer between 0 and 23. DAY The day of the month, as an integer between 1 and 31. MONTH The month of the year, as an integer between 1 and 12. YEAR The year, an integer typically greater than 1900. DOW The day of week, as an integer between 0 and 6, where 0 stands for Sunday. DST `t' if daylight savings time is effect, otherwise `nil'. ZONE An integer indicating the time zone, as the number of seconds east of Greenwich. Note that Common Lisp has different meanings for DOW and ZONE. - Function: encode-time SECONDS MINUTES HOUR DAY MONTH YEAR &optional ZONE This function is the inverse of `decode-time'. It converts seven items of calendrical data into a time value. For the meanings of the arguments, see the table above under `decode-time'. Year numbers less than 100 are treated just like other year numbers. If you want them to stand for years above 1900, you must alter them yourself before you call `encode-time'. The optional argument ZONE defaults to the current time zone and its daylight savings time rules. If specified, it can be either a list (as you would get from `current-time-zone') or an integer (as you would get from `decode-time'). The specified zone is used without any further alteration for daylight savings time.  File: lispref.info, Node: Timers, Next: Terminal Input, Prev: Time Conversion, Up: System Interface Timers for Delayed Execution ============================ You can set up a timer to call a function at a specified future time. - Function: add-timeout SECS FUNCTION OBJECT &optional RESIGNAL This function adds a timeout, to be signaled after the timeout period has elapsed. SECS is a number of seconds, expressed as an integer or a float. FUNCTION will be called after that many seconds have elapsed, with one argument, the given OBJECT. If the optional RESIGNAL argument is provided, then after this timeout expires, `add-timeout' will automatically be called again with RESIGNAL as the first argument. This function returns an object which is the "id" of this particular timeout. You can pass that object to `disable-timeout' to turn off the timeout before it has been signalled. The number of seconds may be expressed as a floating-point number, in which case some fractional part of a second will be used. Caveat: the usable timeout granularity will vary from system to system. Adding a timeout causes a timeout event to be returned by `next-event', and the function will be invoked by `dispatch-event', so if XEmacs is in a tight loop, the function will not be invoked until the next call to sit-for or until the return to top-level (the same is true of process filters). WARNING: if you are thinking of calling add-timeout from inside of a callback function as a way of resignalling a timeout, think again. There is a race condition. That's why the RESIGNAL argument exists. (NOTE: In FSF Emacs, this function is called `run-at-time' and has different semantics.) - Function: disable-timeout ID Cancel the requested action for ID, which should be a value previously returned by `add-timeout'. This cancels the effect of that call to `add-timeout'; the arrival of the specified time will not cause anything special to happen. (NOTE: In FSF Emacs, this function is called `cancel-timer'.)  File: lispref.info, Node: Terminal Input, Next: Terminal Output, Prev: Timers, Up: System Interface Terminal Input ============== This section describes functions and variables for recording or manipulating terminal input. See *Note Display::, for related functions. * Menu: * Input Modes:: Options for how input is processed. * Translating Input:: Low level conversion of some characters or events into others. * Recording Input:: Saving histories of recent or all input events.  File: lispref.info, Node: Input Modes, Next: Translating Input, Up: Terminal Input Input Modes ----------- - Function: set-input-mode INTERRUPT FLOW META QUIT-CHAR This function sets the mode for reading keyboard input. If INTERRUPT is non-null, then XEmacs uses input interrupts. If it is `nil', then it uses CBREAK mode. When XEmacs communicates directly with X, it ignores this argument and uses interrupts if that is the way it knows how to communicate. If FLOW is non-`nil', then XEmacs uses XON/XOFF (`C-q', `C-s') flow control for output to the terminal. This has no effect except in CBREAK mode. *Note Flow Control::. The default setting is system dependent. Some systems always use CBREAK mode regardless of what is specified. The argument META controls support for input character codes above 127. If META is `t', XEmacs converts characters with the 8th bit set into Meta characters. If META is `nil', XEmacs disregards the 8th bit; this is necessary when the terminal uses it as a parity bit. If META is neither `t' nor `nil', XEmacs uses all 8 bits of input unchanged. This is good for terminals using European 8-bit character sets. If QUIT-CHAR is non-`nil', it specifies the character to use for quitting. Normally this character is `C-g'. *Note Quitting::. The `current-input-mode' function returns the input mode settings XEmacs is currently using. - Function: current-input-mode This function returns current mode for reading keyboard input. It returns a list, corresponding to the arguments of `set-input-mode', of the form `(INTERRUPT FLOW META QUIT)' in which: INTERRUPT is non-`nil' when XEmacs is using interrupt-driven input. If `nil', Emacs is using CBREAK mode. FLOW is non-`nil' if XEmacs uses XON/XOFF (`C-q', `C-s') flow control for output to the terminal. This value has no effect unless INTERRUPT is non-`nil'. META is `t' if XEmacs treats the eighth bit of input characters as the meta bit; `nil' means XEmacs clears the eighth bit of every input character; any other value means XEmacs uses all eight bits as the basic character code. QUIT is the character XEmacs currently uses for quitting, usually `C-g'.  File: lispref.info, Node: Translating Input, Next: Recording Input, Prev: Input Modes, Up: Terminal Input Translating Input Events ------------------------ This section describes features for translating input events into other input events before they become part of key sequences. - Variable: function-key-map This variable holds a keymap that describes the character sequences sent by function keys on an ordinary character terminal. This keymap uses the same data structure as other keymaps, but is used differently: it specifies translations to make while reading events. If `function-key-map' "binds" a key sequence K to a vector V, then when K appears as a subsequence *anywhere* in a key sequence, it is replaced with the events in V. For example, VT100 terminals send ` O P' when the keypad PF1 key is pressed. Therefore, we want XEmacs to translate that sequence of events into the single event `pf1'. We accomplish this by "binding" ` O P' to `[pf1]' in `function-key-map', when using a VT100. Thus, typing `C-c ' sends the character sequence `C-c O P'; later the function `read-key-sequence' translates this back into `C-c ', which it returns as the vector `[?\C-c pf1]'. Entries in `function-key-map' are ignored if they conflict with bindings made in the minor mode, local, or global keymaps. The intent is that the character sequences that function keys send should not have command bindings in their own right. The value of `function-key-map' is usually set up automatically according to the terminal's Terminfo or Termcap entry, but sometimes those need help from terminal-specific Lisp files. XEmacs comes with terminal-specific files for many common terminals; their main purpose is to make entries in `function-key-map' beyond those that can be deduced from Termcap and Terminfo. *Note Terminal-Specific::. Emacs versions 18 and earlier used totally different means of detecting the character sequences that represent function keys. - Variable: key-translation-map This variable is another keymap used just like `function-key-map' to translate input events into other events. It differs from `function-key-map' in two ways: * `key-translation-map' goes to work after `function-key-map' is finished; it receives the results of translation by `function-key-map'. * `key-translation-map' overrides actual key bindings. The intent of `key-translation-map' is for users to map one character set to another, including ordinary characters normally bound to `self-insert-command'. You can use `function-key-map' or `key-translation-map' for more than simple aliases, by using a function, instead of a key sequence, as the "translation" of a key. Then this function is called to compute the translation of that key. The key translation function receives one argument, which is the prompt that was specified in `read-key-sequence'--or `nil' if the key sequence is being read by the editor command loop. In most cases you can ignore the prompt value. If the function reads input itself, it can have the effect of altering the event that follows. For example, here's how to define `C-c h' to turn the character that follows into a Hyper character: (defun hyperify (prompt) (let ((e (read-event))) (vector (if (numberp e) (logior (lsh 1 20) e) (if (memq 'hyper (event-modifiers e)) e (add-event-modifier "H-" e)))))) (defun add-event-modifier (string e) (let ((symbol (if (symbolp e) e (car e)))) (setq symbol (intern (concat string (symbol-name symbol)))) (if (symbolp e) symbol (cons symbol (cdr e))))) (define-key function-key-map "\C-ch" 'hyperify) The `iso-transl' library uses this feature to provide a way of inputting non-ASCII Latin-1 characters.  File: lispref.info, Node: Recording Input, Prev: Translating Input, Up: Terminal Input Recording Input --------------- - Function: recent-keys This function returns a vector containing the last 100 input events from the keyboard or mouse. All input events are included, whether or not they were used as parts of key sequences. Thus, you always get the last 100 inputs, not counting keyboard macros. (Events from keyboard macros are excluded because they are less interesting for debugging; it should be enough to see the events that invoked the macros.) - Command: open-dribble-file FILENAME This function opens a "dribble file" named FILENAME. When a dribble file is open, each input event from the keyboard or mouse (but not those from keyboard macros) is written in that file. A non-character event is expressed using its printed representation surrounded by `<...>'. You close the dribble file by calling this function with an argument of `nil'. This function is normally used to record the input necessary to trigger an XEmacs bug, for the sake of a bug report. (open-dribble-file "~/dribble") => nil See also the `open-termscript' function (*note Terminal Output::.).  File: lispref.info, Node: Terminal Output, Next: Flow Control, Prev: Terminal Input, Up: System Interface Terminal Output =============== The terminal output functions send output to the terminal or keep track of output sent to the terminal. The function `device-baud-rate' tells you what XEmacs thinks is the output speed of the terminal. - Function: device-baud-rate &optional DEVICE This function's value is the output speed of the terminal associated with DEVICE, as far as XEmacs knows. DEVICE defaults to the selected device (usually the only device) if omitted. Changing this value does not change the speed of actual data transmission, but the value is used for calculations such as padding. This value has no effect for window-system devices. (This is different in FSF Emacs, where the baud rate also affects decisions about whether to scroll part of the screen or repaint, even when using a window system.) The value is measured in bits per second. XEmacs attempts to automatically initialize the baud rate by querying the terminal. If you are running across a network, however, and different parts of the network work are at different baud rates, the value returned by XEmacs may be different from the value used by your local terminal. Some network protocols communicate the local terminal speed to the remote machine, so that XEmacs and other programs can get the proper value, but others do not. If XEmacs has the wrong value, it makes decisions that are less than optimal. To fix the problem, use `set-device-baud-rate'. - Function: set-device-baud-rate &optional DEVICE This function sets the output speed of DEVICE. See `device-baud-rate'. DEVICE defaults to the selected device (usually the only device) if omitted. - Function: send-string-to-terminal CHAR-OR-STRING &optional STDOUT-P DEVICE This function sends CHAR-OR-STRING to the terminal without alteration. Control characters in CHAR-OR-STRING have terminal-dependent effects. If DEVICE is `nil', this function writes to XEmacs's stderr, or to stdout if STDOUT-P is non-`nil'. Otherwise, DEVICE should be a tty or stream device, and the function writes to the device's normal or error output, according to STDOUT-P. One use of this function is to define function keys on terminals that have downloadable function key definitions. For example, this is how on certain terminals to define function key 4 to move forward four characters (by transmitting the characters `C-u C-f' to the computer): (send-string-to-terminal "\eF4\^U\^F") => nil - Command: open-termscript FILENAME This function is used to open a "termscript file" that will record all the characters sent by XEmacs to the terminal. (If there are multiple tty or stream devices, all characters sent to all such devices are recorded.) The funcion returns `nil'. Termscript files are useful for investigating problems where XEmacs garbles the screen, problems that are due to incorrect Termcap entries or to undesirable settings of terminal options more often than to actual XEmacs bugs. Once you are certain which characters were actually output, you can determine reliably whether they correspond to the Termcap specifications in use. A `nil' value for FILENAME stops recording terminal output. See also `open-dribble-file' in *Note Terminal Input::. (open-termscript "../junk/termscript") => nil  File: lispref.info, Node: Flow Control, Next: Batch Mode, Prev: Terminal Output, Up: System Interface Flow Control ============ This section attempts to answer the question "Why does XEmacs choose to use flow-control characters in its command character set?" For a second view on this issue, read the comments on flow control in the `emacs/INSTALL' file from the distribution; for help with Termcap entries and DEC terminal concentrators, see `emacs/etc/TERMS'. At one time, most terminals did not need flow control, and none used `C-s' and `C-q' for flow control. Therefore, the choice of `C-s' and `C-q' as command characters was uncontroversial. XEmacs, for economy of keystrokes and portability, used nearly all the ASCII control characters, with mnemonic meanings when possible; thus, `C-s' for search and `C-q' for quote. Later, some terminals were introduced which required these characters for flow control. They were not very good terminals for full-screen editing, so XEmacs maintainers did not pay attention. In later years, flow control with `C-s' and `C-q' became widespread among terminals, but by this time it was usually an option. And the majority of users, who can turn flow control off, were unwilling to switch to less mnemonic key bindings for the sake of flow control. So which usage is "right", XEmacs's or that of some terminal and concentrator manufacturers? This question has no simple answer. One reason why we are reluctant to cater to the problems caused by `C-s' and `C-q' is that they are gratuitous. There are other techniques (albeit less common in practice) for flow control that preserve transparency of the character stream. Note also that their use for flow control is not an official standard. Interestingly, on the model 33 teletype with a paper tape punch (which is very old), `C-s' and `C-q' were sent by the computer to turn the punch on and off! As X servers and other window systems replace character-only terminals, this problem is gradually being cured. For the mean time, XEmacs provides a convenient way of enabling flow control if you want it: call the function `enable-flow-control'. - Function: enable-flow-control This function enables use of `C-s' and `C-q' for output flow control, and provides the characters `C-\' and `C-^' as aliases for them using `keyboard-translate-table' (*note Translating Input::.). You can use the function `enable-flow-control-on' in your `.emacs' file to enable flow control automatically on certain terminal types. - Function: enable-flow-control-on &rest TERMTYPES This function enables flow control, and the aliases `C-\' and `C-^', if the terminal type is one of TERMTYPES. For example: (enable-flow-control-on "vt200" "vt300" "vt101" "vt131") Here is how `enable-flow-control' does its job: 1. It sets CBREAK mode for terminal input, and tells the operating system to handle flow control, with `(set-input-mode nil t)'. 2. It sets up `keyboard-translate-table' to translate `C-\' and `C-^' into `C-s' and `C-q'. Except at its very lowest level, XEmacs never knows that the characters typed were anything but `C-s' and `C-q', so you can in effect type them as `C-\' and `C-^' even when they are input for other commands. *Note Translating Input::. If the terminal is the source of the flow control characters, then once you enable kernel flow control handling, you probably can make do with less padding than normal for that terminal. You can reduce the amount of padding by customizing the Termcap entry. You can also reduce it by setting `baud-rate' to a smaller value so that XEmacs uses a smaller speed when calculating the padding needed. *Note Terminal Output::.  File: lispref.info, Node: Batch Mode, Prev: Flow Control, Up: System Interface Batch Mode ========== The command line option `-batch' causes XEmacs to run noninteractively. In this mode, XEmacs does not read commands from the terminal, it does not alter the terminal modes, and it does not expect to be outputting to an erasable screen. The idea is that you specify Lisp programs to run; when they are finished, XEmacs should exit. The way to specify the programs to run is with `-l FILE', which loads the library named FILE, and `-f FUNCTION', which calls FUNCTION with no arguments. Any Lisp program output that would normally go to the echo area, either using `message' or using `prin1', etc., with `t' as the stream, goes instead to XEmacs's standard error descriptor when in batch mode. Thus, XEmacs behaves much like a noninteractive application program. (The echo area output that XEmacs itself normally generates, such as command echoing, is suppressed entirely.) - Function: noninteractive This function returns non-`nil' when XEmacs is running in batch mode. - Variable: noninteractive This variable is non-`nil' when XEmacs is running in batch mode. Setting this variable to `nil', however, will not change whether XEmacs is running in batch mode, and will not change the return value of the `noninteractive' function.  File: lispref.info, Node: X-Windows, Next: ToolTalk Support, Prev: System Interface, Up: Top Functions Specific to the X Window System ***************************************** XEmacs provides the concept of "devices", which generalizes connections to an X server, a TTY device, etc. Most information about an X server that XEmacs is connected to can be determined through general console and device functions. *Note Consoles and Devices::. However, there are some features of the X Window System that do not generalize well, and they are covered specially here. * Menu: * X Selections:: Transferring text to and from other X clients. * X Server:: Information about the X server connected to a particular device. * X Miscellaneous:: Other X-specific functions and variables.  File: lispref.info, Node: X Selections, Next: X Server, Up: X-Windows X Selections ============ The X server records a set of "selections" which permit transfer of data between application programs. The various selections are distinguished by "selection types", represented in XEmacs by symbols. X clients including XEmacs can read or set the selection for any given type. - Function: x-own-selection DATA &optional TYPE This function sets a "selection" in the X server. It takes two arguments: a value, DATA, and the selection type TYPE to assign it to. DATA may be a string, a cons of two markers, or an extent. In the latter cases, the selection is considered to be the text between the markers, or between the extent's endpoints. Each possible TYPE has its own selection value, which changes independently. The usual values of TYPE are `PRIMARY' and `SECONDARY'; these are symbols with upper-case names, in accord with X Windows conventions. The default is `PRIMARY'. (In FSF Emacs, this function is called `x-set-selection' and takes different arguments.) - Function: x-get-selection This function accesses selections set up by XEmacs or by other X clients. It returns the value of the current primary selection. - Function: x-disown-selection &optional SECONDARY-P Assuming we own the selection, this function disowns it. If SECONDARY-P is non-`nil', the secondary selection instead of the primary selection is discarded. The X server also has a set of numbered "cut buffers" which can store text or other data being moved between applications. Cut buffers are considered obsolete, but XEmacs supports them for the sake of X clients that still use them. - Function: x-get-cutbuffer &optional N This function returns the contents of cut buffer number N. (This function is called `x-get-cut-buffer' in FSF Emacs.) - Function: x-store-cutbuffer STRING This function stores STRING into the first cut buffer (cut buffer 0), moving the other values down through the series of cut buffers, kill-ring-style. (This function is called `x-set-cut-buffer' in FSF Emacs.)  File: lispref.info, Node: X Server, Next: X Miscellaneous, Prev: X Selections, Up: X-Windows X Server ======== This section describes how to access and change the overall status of the X server XEmacs is using. * Menu: * Resources:: Getting resource values from the server. * Server Data:: Getting info about the X server. * Grabs:: Restricting access to the server by other apps.  File: lispref.info, Node: Resources, Next: Server Data, Up: X Server Resources --------- - Function: default-x-device This function return the default X device for resourcing. This is the first-created X device that still exists. - Function: x-get-resource NAME CLASS TYPE &optional LOCALE DEVICE NOERROR This function retrieves a resource value from the X resource manager. * The first arg is the name of the resource to retrieve, such as `"font"'. * The second arg is the class of the resource to retrieve, like `"Font"'. * The third arg should be one of the symbols `string', `integer', `natnum', or `boolean', specifying the type of object that the database is searched for. * The fourth arg is the locale to search for the resources on, and can currently be a a buffer, a frame, a device, or the symbol `global'. If omitted, it defaults to `global'. * The fifth arg is the device to search for the resources on. (The resource database for a particular device is constructed by combining non-device- specific resources such any command-line resources specified and any app-defaults files found [or the fallback resources supplied by XEmacs, if no app-defaults file is found] with device-specific resources such as those supplied using `xrdb'.) If omitted, it defaults to the device of LOCALE, if a device can be derived (i.e. if LOCALE is a frame or device), and otherwise defaults to the value of `default-x-device'. * The sixth arg NOERROR, if non-`nil', means do not signal an error if a bogus resource specification was retrieved (e.g. if a non-integer was given when an integer was requested). In this case, a warning is issued instead. The resource names passed to this function are looked up relative to the locale. If you want to search for a subresource, you just need to specify the resource levels in NAME and CLASS. For example, NAME could be `"modeline.attributeFont"', and CLASS `"Face.AttributeFont"'. Specifically, 1. If LOCALE is a buffer, a call `(x-get-resource "foreground" "Foreground" 'string SOME-BUFFER)' is an interface to a C call something like `XrmGetResource (db, "xemacs.buffer.BUFFER-NAME.foreground", "Emacs.EmacsLocaleType.EmacsBuffer.Foreground", "String");' 2. If LOCALE is a frame, a call `(x-get-resource "foreground" "Foreground" 'string SOME-FRAME)' is an interface to a C call something like `XrmGetResource (db, "xemacs.frame.FRAME-NAME.foreground", "Emacs.EmacsLocaleType.EmacsFrame.Foreground", "String");' 3. If LOCALE is a device, a call `(x-get-resource "foreground" "Foreground" 'string SOME-DEVICE)' is an interface to a C call something like `XrmGetResource (db, "xemacs.device.DEVICE-NAME.foreground", "Emacs.EmacsLocaleType.EmacsDevice.Foreground", "String");' 4. If LOCALE is the symbol `global', a call `(x-get-resource "foreground" "Foreground" 'string 'global)' is an interface to a C call something like `XrmGetResource (db, "xemacs.foreground", "Emacs.Foreground", "String");' Note that for `global', no prefix is added other than that of the application itself; thus, you can use this locale to retrieve arbitrary application resources, if you really want to. The returned value of this function is `nil' if the queried resource is not found. If TYPE is `string', a string is returned, and if it is `integer', an integer is returned. If TYPE is `boolean', then the returned value is the list `(t)' for true, `(nil)' for false, and is `nil' to mean "unspecified". - Function: x-put-resource RESOURCE-LINE &optional DEVICE This function adds a resource to the resource database for DEVICE. RESOURCE-LINE specifies the resource to add and should be a standard resource specification. - Variable: x-emacs-application-class This variable holds The X application class of the XEmacs process. This controls, among other things, the name of the "app-defaults" file that XEmacs will use. For changes to this variable to take effect, they must be made before the connection to the X server is initialized, that is, this variable may only be changed before XEmacs is dumped, or by setting it in the file `lisp/term/x-win.el'.