1 @comment %**start of header (This is for running Texinfo on a region.)
2 @setfilename rltech.info
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7 This document describes the GNU Readline Library, a utility for aiding
8 in the consitency of user interface across discrete programs that need
9 to provide a command line interface.
11 Copyright (C) 1988-2002 Free Software Foundation, Inc.
13 Permission is granted to make and distribute verbatim copies of
14 this manual provided the copyright notice and this permission notice
15 pare preserved on all copies.
18 Permission is granted to process this file through TeX and print the
19 results, provided the printed document carries copying permission
20 notice identical to this one except for the removal of this paragraph
21 (this paragraph not being relevant to the printed manual).
24 Permission is granted to copy and distribute modified versions of this
25 manual under the conditions for verbatim copying, provided that the entire
26 resulting derived work is distributed under the terms of a permission
27 notice identical to this one.
29 Permission is granted to copy and distribute translations of this manual
30 into another language, under the above conditions for modified versions,
31 except that this permission notice may be stated in a translation approved
35 @node Programming with GNU Readline
36 @chapter Programming with GNU Readline
38 This chapter describes the interface between the @sc{gnu} Readline Library and
39 other programs. If you are a programmer, and you wish to include the
40 features found in @sc{gnu} Readline
41 such as completion, line editing, and interactive history manipulation
42 in your own programs, this section is for you.
45 * Basic Behavior:: Using the default behavior of Readline.
46 * Custom Functions:: Adding your own functions to Readline.
47 * Readline Variables:: Variables accessible to custom
49 * Readline Convenience Functions:: Functions which Readline supplies to
50 aid in writing your own custom
52 * Readline Signal Handling:: How Readline behaves when it receives signals.
53 * Custom Completers:: Supplanting or supplementing Readline's
58 @section Basic Behavior
60 Many programs provide a command line interface, such as @code{mail},
61 @code{ftp}, and @code{sh}. For such programs, the default behaviour of
62 Readline is sufficient. This section describes how to use Readline in
63 the simplest way possible, perhaps to replace calls in your code to
64 @code{gets()} or @code{fgets()}.
67 @cindex readline, function
69 The function @code{readline()} prints a prompt @var{prompt}
70 and then reads and returns a single line of text from the user.
71 If @var{prompt} is @code{NULL} or the empty string, no prompt is displayed.
72 The line @code{readline} returns is allocated with @code{malloc()};
73 the caller should @code{free()} the line when it has finished with it.
74 The declaration for @code{readline} in ANSI C is
77 @code{char *readline (const char *@var{prompt});}
83 @code{char *line = readline ("Enter a line: ");}
86 in order to read a line of text from the user.
87 The line returned has the final newline removed, so only the
90 If @code{readline} encounters an @code{EOF} while reading the line, and the
91 line is empty at that point, then @code{(char *)NULL} is returned.
92 Otherwise, the line is ended just as if a newline had been typed.
94 If you want the user to be able to get at the line later, (with
95 @key{C-p} for example), you must call @code{add_history()} to save the
96 line away in a @dfn{history} list of such lines.
99 @code{add_history (line)};
103 For full details on the GNU History Library, see the associated manual.
105 It is preferable to avoid saving empty lines on the history list, since
106 users rarely have a burning need to reuse a blank line. Here is
107 a function which usefully replaces the standard @code{gets()} library
108 function, and has the advantage of no static buffer to overflow:
111 /* A static variable for holding the line. */
112 static char *line_read = (char *)NULL;
114 /* Read a string, and return a pointer to it.
115 Returns NULL on EOF. */
119 /* If the buffer has already been allocated,
120 return the memory to the free pool. */
124 line_read = (char *)NULL;
127 /* Get a line from the user. */
128 line_read = readline ("");
130 /* If the line has any text in it,
131 save it on the history. */
132 if (line_read && *line_read)
133 add_history (line_read);
139 This function gives the user the default behaviour of @key{TAB}
140 completion: completion on file names. If you do not want Readline to
141 complete on filenames, you can change the binding of the @key{TAB} key
142 with @code{rl_bind_key()}.
145 @code{int rl_bind_key (int @var{key}, rl_command_func_t *@var{function});}
148 @code{rl_bind_key()} takes two arguments: @var{key} is the character that
149 you want to bind, and @var{function} is the address of the function to
150 call when @var{key} is pressed. Binding @key{TAB} to @code{rl_insert()}
151 makes @key{TAB} insert itself.
152 @code{rl_bind_key()} returns non-zero if @var{key} is not a valid
153 ASCII character code (between 0 and 255).
155 Thus, to disable the default @key{TAB} behavior, the following suffices:
157 @code{rl_bind_key ('\t', rl_insert);}
160 This code should be executed once at the start of your program; you
161 might write a function called @code{initialize_readline()} which
162 performs this and other desired initializations, such as installing
163 custom completers (@pxref{Custom Completers}).
165 @node Custom Functions
166 @section Custom Functions
168 Readline provides many functions for manipulating the text of
169 the line, but it isn't possible to anticipate the needs of all
170 programs. This section describes the various functions and variables
171 defined within the Readline library which allow a user program to add
172 customized functionality to Readline.
174 Before declaring any functions that customize Readline's behavior, or
175 using any functionality Readline provides in other code, an
176 application writer should include the file @code{<readline/readline.h>}
177 in any file that uses Readline's features. Since some of the definitions
178 in @code{readline.h} use the @code{stdio} library, the file
179 @code{<stdio.h>} should be included before @code{readline.h}.
181 @code{readline.h} defines a C preprocessor variable that should
182 be treated as an integer, @code{RL_READLINE_VERSION}, which may
183 be used to conditionally compile application code depending on
184 the installed Readline version. The value is a hexadecimal
185 encoding of the major and minor version numbers of the library,
186 of the form 0x@var{MMmm}. @var{MM} is the two-digit major
187 version number; @var{mm} is the two-digit minor version number.
188 For Readline 4.2, for example, the value of
189 @code{RL_READLINE_VERSION} would be @code{0x0402}.
192 * Readline Typedefs:: C declarations to make code readable.
193 * Function Writing:: Variables and calling conventions.
196 @node Readline Typedefs
197 @subsection Readline Typedefs
199 For readabilty, we declare a number of new object types, all pointers
202 The reason for declaring these new types is to make it easier to write
203 code describing pointers to C functions with appropriately prototyped
204 arguments and return values.
206 For instance, say we want to declare a variable @var{func} as a pointer
207 to a function which takes two @code{int} arguments and returns an
208 @code{int} (this is the type of all of the Readline bindable functions).
209 Instead of the classic C declaration
211 @code{int (*func)();}
214 or the ANSI-C style declaration
216 @code{int (*func)(int, int);}
221 @code{rl_command_func_t *func;}
223 The full list of function pointer types available is
226 @item typedef int rl_command_func_t (int, int);
228 @item typedef char *rl_compentry_func_t (const char *, int);
230 @item typedef char **rl_completion_func_t (const char *, int, int);
232 @item typedef char *rl_quote_func_t (char *, int, char *);
234 @item typedef char *rl_dequote_func_t (char *, int);
236 @item typedef int rl_compignore_func_t (char **);
238 @item typedef void rl_compdisp_func_t (char **, int, int);
240 @item typedef int rl_hook_func_t (void);
242 @item typedef int rl_getc_func_t (FILE *);
244 @item typedef int rl_linebuf_func_t (char *, int);
246 @item typedef int rl_intfunc_t (int);
247 @item #define rl_ivoidfunc_t rl_hook_func_t
248 @item typedef int rl_icpfunc_t (char *);
249 @item typedef int rl_icppfunc_t (char **);
251 @item typedef void rl_voidfunc_t (void);
252 @item typedef void rl_vintfunc_t (int);
253 @item typedef void rl_vcpfunc_t (char *);
254 @item typedef void rl_vcppfunc_t (char **);
258 @node Function Writing
259 @subsection Writing a New Function
261 In order to write new functions for Readline, you need to know the
262 calling conventions for keyboard-invoked functions, and the names of the
263 variables that describe the current state of the line read so far.
265 The calling sequence for a command @code{foo} looks like
268 @code{int foo (int count, int key)}
272 where @var{count} is the numeric argument (or 1 if defaulted) and
273 @var{key} is the key that invoked this function.
275 It is completely up to the function as to what should be done with the
276 numeric argument. Some functions use it as a repeat count, some
277 as a flag, and others to choose alternate behavior (refreshing the current
278 line as opposed to refreshing the screen, for example). Some choose to
279 ignore it. In general, if a
280 function uses the numeric argument as a repeat count, it should be able
281 to do something useful with both negative and positive arguments.
282 At the very least, it should be aware that it can be passed a
285 A command function should return 0 if its action completes successfully,
286 and a non-zero value if some error occurs.
288 @node Readline Variables
289 @section Readline Variables
291 These variables are available to function writers.
293 @deftypevar {char *} rl_line_buffer
294 This is the line gathered so far. You are welcome to modify the
295 contents of the line, but see @ref{Allowing Undoing}. The
296 function @code{rl_extend_line_buffer} is available to increase
297 the memory allocated to @code{rl_line_buffer}.
300 @deftypevar int rl_point
301 The offset of the current cursor position in @code{rl_line_buffer}
305 @deftypevar int rl_end
306 The number of characters present in @code{rl_line_buffer}. When
307 @code{rl_point} is at the end of the line, @code{rl_point} and
308 @code{rl_end} are equal.
311 @deftypevar int rl_mark
312 The @var{mark} (saved position) in the current line. If set, the mark
313 and point define a @emph{region}.
316 @deftypevar int rl_done
317 Setting this to a non-zero value causes Readline to return the current
321 @deftypevar int rl_num_chars_to_read
322 Setting this to a positive value before calling @code{readline()} causes
323 Readline to return after accepting that many characters, rather
324 than reading up to a character bound to @code{accept-line}.
327 @deftypevar int rl_pending_input
328 Setting this to a value makes it the next keystroke read. This is a
329 way to stuff a single character into the input stream.
332 @deftypevar int rl_dispatching
333 Set to a non-zero value if a function is being called from a key binding;
334 zero otherwise. Application functions can test this to discover whether
335 they were called directly or by Readline's dispatching mechanism.
338 @deftypevar int rl_erase_empty_line
339 Setting this to a non-zero value causes Readline to completely erase
340 the current line, including any prompt, any time a newline is typed as
341 the only character on an otherwise-empty line. The cursor is moved to
342 the beginning of the newly-blank line.
345 @deftypevar {char *} rl_prompt
346 The prompt Readline uses. This is set from the argument to
347 @code{readline()}, and should not be assigned to directly.
348 The @code{rl_set_prompt()} function (@pxref{Redisplay}) may
349 be used to modify the prompt string after calling @code{readline()}.
352 @deftypevar int rl_already_prompted
353 If an application wishes to display the prompt itself, rather than have
354 Readline do it the first time @code{readline()} is called, it should set
355 this variable to a non-zero value after displaying the prompt.
356 The prompt must also be passed as the argument to @code{readline()} so
357 the redisplay functions can update the display properly.
358 The calling application is responsible for managing the value; Readline
362 @deftypevar {const char *} rl_library_version
363 The version number of this revision of the library.
366 @deftypevar int rl_readline_version
367 An integer encoding the current version of the library. The encoding is
368 of the form 0x@var{MMmm}, where @var{MM} is the two-digit major version
369 number, and @var{mm} is the two-digit minor version number.
370 For example, for Readline-4.2, @code{rl_readline_version} would have the
374 @deftypevar {int} rl_gnu_readline_p
375 Always set to 1, denoting that this is @sc{gnu} readline rather than some
379 @deftypevar {const char *} rl_terminal_name
380 The terminal type, used for initialization. If not set by the application,
381 Readline sets this to the value of the @env{TERM} environment variable
382 the first time it is called.
385 @deftypevar {const char *} rl_readline_name
386 This variable is set to a unique name by each application using Readline.
387 The value allows conditional parsing of the inputrc file
388 (@pxref{Conditional Init Constructs}).
391 @deftypevar {FILE *} rl_instream
392 The stdio stream from which Readline reads input.
393 If @code{NULL}, Readline defaults to @var{stdin}.
396 @deftypevar {FILE *} rl_outstream
397 The stdio stream to which Readline performs output.
398 If @code{NULL}, Readline defaults to @var{stdout}.
401 @deftypevar {rl_command_func_t *} rl_last_func
402 The address of the last command function Readline executed. May be used to
403 test whether or not a function is being executed twice in succession, for
407 @deftypevar {rl_hook_func_t *} rl_startup_hook
408 If non-zero, this is the address of a function to call just
409 before @code{readline} prints the first prompt.
412 @deftypevar {rl_hook_func_t *} rl_pre_input_hook
413 If non-zero, this is the address of a function to call after
414 the first prompt has been printed and just before @code{readline}
415 starts reading input characters.
418 @deftypevar {rl_hook_func_t *} rl_event_hook
419 If non-zero, this is the address of a function to call periodically
420 when Readline is waiting for terminal input.
421 By default, this will be called at most ten times a second if there
422 is no keyboard input.
425 @deftypevar {rl_getc_func_t *} rl_getc_function
426 If non-zero, Readline will call indirectly through this pointer
427 to get a character from the input stream. By default, it is set to
428 @code{rl_getc}, the default Readline character input function
429 (@pxref{Character Input}).
432 @deftypevar {rl_voidfunc_t *} rl_redisplay_function
433 If non-zero, Readline will call indirectly through this pointer
434 to update the display with the current contents of the editing buffer.
435 By default, it is set to @code{rl_redisplay}, the default Readline
436 redisplay function (@pxref{Redisplay}).
439 @deftypevar {rl_vintfunc_t *} rl_prep_term_function
440 If non-zero, Readline will call indirectly through this pointer
441 to initialize the terminal. The function takes a single argument, an
442 @code{int} flag that says whether or not to use eight-bit characters.
443 By default, this is set to @code{rl_prep_terminal}
444 (@pxref{Terminal Management}).
447 @deftypevar {rl_voidfunc_t *} rl_deprep_term_function
448 If non-zero, Readline will call indirectly through this pointer
449 to reset the terminal. This function should undo the effects of
450 @code{rl_prep_term_function}.
451 By default, this is set to @code{rl_deprep_terminal}
452 (@pxref{Terminal Management}).
455 @deftypevar {Keymap} rl_executing_keymap
456 This variable is set to the keymap (@pxref{Keymaps}) in which the
457 currently executing readline function was found.
460 @deftypevar {Keymap} rl_binding_keymap
461 This variable is set to the keymap (@pxref{Keymaps}) in which the
462 last key binding occurred.
465 @deftypevar {char *} rl_executing_macro
466 This variable is set to the text of any currently-executing macro.
469 @deftypevar {int} rl_readline_state
470 A variable with bit values that encapsulate the current Readline state.
471 A bit is set with the @code{RL_SETSTATE} macro, and unset with the
472 @code{RL_UNSETSTATE} macro. Use the @code{RL_ISSTATE} macro to test
473 whether a particular state bit is set. Current state bits include:
477 Readline has not yet been called, nor has it begun to intialize.
478 @item RL_STATE_INITIALIZING
479 Readline is initializing its internal data structures.
480 @item RL_STATE_INITIALIZED
481 Readline has completed its initialization.
482 @item RL_STATE_TERMPREPPED
483 Readline has modified the terminal modes to do its own input and redisplay.
484 @item RL_STATE_READCMD
485 Readline is reading a command from the keyboard.
486 @item RL_STATE_METANEXT
487 Readline is reading more input after reading the meta-prefix character.
488 @item RL_STATE_DISPATCHING
489 Readline is dispatching to a command.
490 @item RL_STATE_MOREINPUT
491 Readline is reading more input while executing an editing command.
492 @item RL_STATE_ISEARCH
493 Readline is performing an incremental history search.
494 @item RL_STATE_NSEARCH
495 Readline is performing a non-incremental history search.
496 @item RL_STATE_SEARCH
497 Readline is searching backward or forward through the history for a string.
498 @item RL_STATE_NUMERICARG
499 Readline is reading a numeric argument.
500 @item RL_STATE_MACROINPUT
501 Readline is currently getting its input from a previously-defined keyboard
503 @item RL_STATE_MACRODEF
504 Readline is currently reading characters defining a keyboard macro.
505 @item RL_STATE_OVERWRITE
506 Readline is in overwrite mode.
507 @item RL_STATE_COMPLETING
508 Readline is performing word completion.
509 @item RL_STATE_SIGHANDLER
510 Readline is currently executing the readline signal handler.
511 @item RL_STATE_UNDOING
512 Readline is performing an undo.
514 Readline has read a key sequence bound to @code{accept-line}
515 and is about to return the line to the caller.
520 @deftypevar {int} rl_explicit_arg
521 Set to a non-zero value if an explicit numeric argument was specified by
522 the user. Only valid in a bindable command function.
525 @deftypevar {int} rl_numeric_arg
526 Set to the value of any numeric argument explicitly specified by the user
527 before executing the current Readline function. Only valid in a bindable
531 @deftypevar {int} rl_editing_mode
532 Set to a value denoting Readline's current editing mode. A value of
533 @var{1} means Readline is currently in emacs mode; @var{0}
534 means that vi mode is active.
538 @node Readline Convenience Functions
539 @section Readline Convenience Functions
542 * Function Naming:: How to give a function you write a name.
543 * Keymaps:: Making keymaps.
544 * Binding Keys:: Changing Keymaps.
545 * Associating Function Names and Bindings:: Translate function names to
547 * Allowing Undoing:: How to make your functions undoable.
548 * Redisplay:: Functions to control line display.
549 * Modifying Text:: Functions to modify @code{rl_line_buffer}.
550 * Character Input:: Functions to read keyboard input.
551 * Terminal Management:: Functions to manage terminal settings.
552 * Utility Functions:: Generally useful functions and hooks.
553 * Miscellaneous Functions:: Functions that don't fall into any category.
554 * Alternate Interface:: Using Readline in a `callback' fashion.
555 * A Readline Example:: An example Readline function.
558 @node Function Naming
559 @subsection Naming a Function
561 The user can dynamically change the bindings of keys while using
562 Readline. This is done by representing the function with a descriptive
563 name. The user is able to type the descriptive name when referring to
564 the function. Thus, in an init file, one might find
567 Meta-Rubout: backward-kill-word
570 This binds the keystroke @key{Meta-Rubout} to the function
571 @emph{descriptively} named @code{backward-kill-word}. You, as the
572 programmer, should bind the functions you write to descriptive names as
573 well. Readline provides a function for doing that:
575 @deftypefun int rl_add_defun (const char *name, rl_command_func_t *function, int key)
576 Add @var{name} to the list of named functions. Make @var{function} be
577 the function that gets called. If @var{key} is not -1, then bind it to
578 @var{function} using @code{rl_bind_key()}.
581 Using this function alone is sufficient for most applications. It is
582 the recommended way to add a few functions to the default functions that
583 Readline has built in. If you need to do something other
584 than adding a function to Readline, you may need to use the
585 underlying functions described below.
588 @subsection Selecting a Keymap
590 Key bindings take place on a @dfn{keymap}. The keymap is the
591 association between the keys that the user types and the functions that
592 get run. You can make your own keymaps, copy existing keymaps, and tell
593 Readline which keymap to use.
595 @deftypefun Keymap rl_make_bare_keymap (void)
596 Returns a new, empty keymap. The space for the keymap is allocated with
597 @code{malloc()}; the caller should free it by calling
598 @code{rl_discard_keymap()} when done.
601 @deftypefun Keymap rl_copy_keymap (Keymap map)
602 Return a new keymap which is a copy of @var{map}.
605 @deftypefun Keymap rl_make_keymap (void)
606 Return a new keymap with the printing characters bound to rl_insert,
607 the lowercase Meta characters bound to run their equivalents, and
608 the Meta digits bound to produce numeric arguments.
611 @deftypefun void rl_discard_keymap (Keymap keymap)
612 Free the storage associated with @var{keymap}.
615 Readline has several internal keymaps. These functions allow you to
616 change which keymap is active.
618 @deftypefun Keymap rl_get_keymap (void)
619 Returns the currently active keymap.
622 @deftypefun void rl_set_keymap (Keymap keymap)
623 Makes @var{keymap} the currently active keymap.
626 @deftypefun Keymap rl_get_keymap_by_name (const char *name)
627 Return the keymap matching @var{name}. @var{name} is one which would
628 be supplied in a @code{set keymap} inputrc line (@pxref{Readline Init File}).
631 @deftypefun {char *} rl_get_keymap_name (Keymap keymap)
632 Return the name matching @var{keymap}. @var{name} is one which would
633 be supplied in a @code{set keymap} inputrc line (@pxref{Readline Init File}).
637 @subsection Binding Keys
639 Key sequences are associate with functions through the keymap.
640 Readline has several internal keymaps: @code{emacs_standard_keymap},
641 @code{emacs_meta_keymap}, @code{emacs_ctlx_keymap},
642 @code{vi_movement_keymap}, and @code{vi_insertion_keymap}.
643 @code{emacs_standard_keymap} is the default, and the examples in
644 this manual assume that.
646 Since @code{readline()} installs a set of default key bindings the first
647 time it is called, there is always the danger that a custom binding
648 installed before the first call to @code{readline()} will be overridden.
649 An alternate mechanism is to install custom key bindings in an
650 initialization function assigned to the @code{rl_startup_hook} variable
651 (@pxref{Readline Variables}).
653 These functions manage key bindings.
655 @deftypefun int rl_bind_key (int key, rl_command_func_t *function)
656 Binds @var{key} to @var{function} in the currently active keymap.
657 Returns non-zero in the case of an invalid @var{key}.
660 @deftypefun int rl_bind_key_in_map (int key, rl_command_func_t *function, Keymap map)
661 Bind @var{key} to @var{function} in @var{map}. Returns non-zero in the case
662 of an invalid @var{key}.
665 @deftypefun int rl_unbind_key (int key)
666 Bind @var{key} to the null function in the currently active keymap.
667 Returns non-zero in case of error.
670 @deftypefun int rl_unbind_key_in_map (int key, Keymap map)
671 Bind @var{key} to the null function in @var{map}.
672 Returns non-zero in case of error.
675 @deftypefun int rl_unbind_function_in_map (rl_command_func_t *function, Keymap map)
676 Unbind all keys that execute @var{function} in @var{map}.
679 @deftypefun int rl_unbind_command_in_map (const char *command, Keymap map)
680 Unbind all keys that are bound to @var{command} in @var{map}.
683 @deftypefun int rl_set_key (const char *keyseq, rl_command_func_t *function, Keymap map)
684 Bind the key sequence represented by the string @var{keyseq} to the function
685 @var{function}. This makes new keymaps as
686 necessary. The initial keymap in which to do bindings is @var{map}.
689 @deftypefun int rl_generic_bind (int type, const char *keyseq, char *data, Keymap map)
690 Bind the key sequence represented by the string @var{keyseq} to the arbitrary
691 pointer @var{data}. @var{type} says what kind of data is pointed to by
692 @var{data}; this can be a function (@code{ISFUNC}), a macro
693 (@code{ISMACR}), or a keymap (@code{ISKMAP}). This makes new keymaps as
694 necessary. The initial keymap in which to do bindings is @var{map}.
697 @deftypefun int rl_parse_and_bind (char *line)
698 Parse @var{line} as if it had been read from the @code{inputrc} file and
699 perform any key bindings and variable assignments found
700 (@pxref{Readline Init File}).
703 @deftypefun int rl_read_init_file (const char *filename)
704 Read keybindings and variable assignments from @var{filename}
705 (@pxref{Readline Init File}).
708 @node Associating Function Names and Bindings
709 @subsection Associating Function Names and Bindings
711 These functions allow you to find out what keys invoke named functions
712 and the functions invoked by a particular key sequence. You may also
713 associate a new function name with an arbitrary function.
715 @deftypefun {rl_command_func_t *} rl_named_function (const char *name)
716 Return the function with name @var{name}.
719 @deftypefun {rl_command_func_t *} rl_function_of_keyseq (const char *keyseq, Keymap map, int *type)
720 Return the function invoked by @var{keyseq} in keymap @var{map}.
721 If @var{map} is @code{NULL}, the current keymap is used. If @var{type} is
722 not @code{NULL}, the type of the object is returned in the @code{int} variable
723 it points to (one of @code{ISFUNC}, @code{ISKMAP}, or @code{ISMACR}).
726 @deftypefun {char **} rl_invoking_keyseqs (rl_command_func_t *function)
727 Return an array of strings representing the key sequences used to
728 invoke @var{function} in the current keymap.
731 @deftypefun {char **} rl_invoking_keyseqs_in_map (rl_command_func_t *function, Keymap map)
732 Return an array of strings representing the key sequences used to
733 invoke @var{function} in the keymap @var{map}.
736 @deftypefun void rl_function_dumper (int readable)
737 Print the readline function names and the key sequences currently
738 bound to them to @code{rl_outstream}. If @var{readable} is non-zero,
739 the list is formatted in such a way that it can be made part of an
740 @code{inputrc} file and re-read.
743 @deftypefun void rl_list_funmap_names (void)
744 Print the names of all bindable Readline functions to @code{rl_outstream}.
747 @deftypefun {const char **} rl_funmap_names (void)
748 Return a NULL terminated array of known function names. The array is
749 sorted. The array itself is allocated, but not the strings inside. You
750 should @code{free()} the array when you are done, but not the pointers.
753 @deftypefun int rl_add_funmap_entry (const char *name, rl_command_func_t *function)
754 Add @var{name} to the list of bindable Readline command names, and make
755 @var{function} the function to be called when @var{name} is invoked.
758 @node Allowing Undoing
759 @subsection Allowing Undoing
761 Supporting the undo command is a painless thing, and makes your
762 functions much more useful. It is certainly easy to try
763 something if you know you can undo it.
765 If your function simply inserts text once, or deletes text once, and
766 uses @code{rl_insert_text()} or @code{rl_delete_text()} to do it, then
767 undoing is already done for you automatically.
769 If you do multiple insertions or multiple deletions, or any combination
770 of these operations, you should group them together into one operation.
771 This is done with @code{rl_begin_undo_group()} and
772 @code{rl_end_undo_group()}.
774 The types of events that can be undone are:
777 enum undo_code @{ UNDO_DELETE, UNDO_INSERT, UNDO_BEGIN, UNDO_END @};
780 Notice that @code{UNDO_DELETE} means to insert some text, and
781 @code{UNDO_INSERT} means to delete some text. That is, the undo code
782 tells what to undo, not how to undo it. @code{UNDO_BEGIN} and
783 @code{UNDO_END} are tags added by @code{rl_begin_undo_group()} and
784 @code{rl_end_undo_group()}.
786 @deftypefun int rl_begin_undo_group (void)
787 Begins saving undo information in a group construct. The undo
788 information usually comes from calls to @code{rl_insert_text()} and
789 @code{rl_delete_text()}, but could be the result of calls to
790 @code{rl_add_undo()}.
793 @deftypefun int rl_end_undo_group (void)
794 Closes the current undo group started with @code{rl_begin_undo_group
795 ()}. There should be one call to @code{rl_end_undo_group()}
796 for each call to @code{rl_begin_undo_group()}.
799 @deftypefun void rl_add_undo (enum undo_code what, int start, int end, char *text)
800 Remember how to undo an event (according to @var{what}). The affected
801 text runs from @var{start} to @var{end}, and encompasses @var{text}.
804 @deftypefun void rl_free_undo_list (void)
805 Free the existing undo list.
808 @deftypefun int rl_do_undo (void)
809 Undo the first thing on the undo list. Returns @code{0} if there was
810 nothing to undo, non-zero if something was undone.
813 Finally, if you neither insert nor delete text, but directly modify the
814 existing text (e.g., change its case), call @code{rl_modifying()}
815 once, just before you modify the text. You must supply the indices of
816 the text range that you are going to modify.
818 @deftypefun int rl_modifying (int start, int end)
819 Tell Readline to save the text between @var{start} and @var{end} as a
820 single undo unit. It is assumed that you will subsequently modify
825 @subsection Redisplay
827 @deftypefun void rl_redisplay (void)
828 Change what's displayed on the screen to reflect the current contents
829 of @code{rl_line_buffer}.
832 @deftypefun int rl_forced_update_display (void)
833 Force the line to be updated and redisplayed, whether or not
834 Readline thinks the screen display is correct.
837 @deftypefun int rl_on_new_line (void)
838 Tell the update functions that we have moved onto a new (empty) line,
839 usually after ouputting a newline.
842 @deftypefun int rl_on_new_line_with_prompt (void)
843 Tell the update functions that we have moved onto a new line, with
844 @var{rl_prompt} already displayed.
845 This could be used by applications that want to output the prompt string
846 themselves, but still need Readline to know the prompt string length for
848 It should be used after setting @var{rl_already_prompted}.
851 @deftypefun int rl_reset_line_state (void)
852 Reset the display state to a clean state and redisplay the current line
853 starting on a new line.
856 @deftypefun int rl_crlf (void)
857 Move the cursor to the start of the next screen line.
860 @deftypefun int rl_show_char (int c)
861 Display character @var{c} on @code{rl_outstream}.
862 If Readline has not been set to display meta characters directly, this
863 will convert meta characters to a meta-prefixed key sequence.
864 This is intended for use by applications which wish to do their own
868 @deftypefun int rl_message (const char *, @dots{})
869 The arguments are a format string as would be supplied to @code{printf},
870 possibly containing conversion specifications such as @samp{%d}, and
871 any additional arguments necessary to satisfy the conversion specifications.
872 The resulting string is displayed in the @dfn{echo area}. The echo area
873 is also used to display numeric arguments and search strings.
876 @deftypefun int rl_clear_message (void)
877 Clear the message in the echo area.
880 @deftypefun void rl_save_prompt (void)
881 Save the local Readline prompt display state in preparation for
882 displaying a new message in the message area with @code{rl_message()}.
885 @deftypefun void rl_restore_prompt (void)
886 Restore the local Readline prompt display state saved by the most
887 recent call to @code{rl_save_prompt}.
890 @deftypefun int rl_expand_prompt (char *prompt)
891 Expand any special character sequences in @var{prompt} and set up the
892 local Readline prompt redisplay variables.
893 This function is called by @code{readline()}. It may also be called to
894 expand the primary prompt if the @code{rl_on_new_line_with_prompt()}
895 function or @code{rl_already_prompted} variable is used.
896 It returns the number of visible characters on the last line of the
897 (possibly multi-line) prompt.
900 @deftypefun int rl_set_prompt (const char *prompt)
901 Make Readline use @var{prompt} for subsequent redisplay. This calls
902 @code{rl_expand_prompt()} to expand the prompt and sets @code{rl_prompt}
907 @subsection Modifying Text
909 @deftypefun int rl_insert_text (const char *text)
910 Insert @var{text} into the line at the current cursor position.
911 Returns the number of characters inserted.
914 @deftypefun int rl_delete_text (int start, int end)
915 Delete the text between @var{start} and @var{end} in the current line.
916 Returns the number of characters deleted.
919 @deftypefun {char *} rl_copy_text (int start, int end)
920 Return a copy of the text between @var{start} and @var{end} in
924 @deftypefun int rl_kill_text (int start, int end)
925 Copy the text between @var{start} and @var{end} in the current line
926 to the kill ring, appending or prepending to the last kill if the
927 last command was a kill command. The text is deleted.
928 If @var{start} is less than @var{end},
929 the text is appended, otherwise prepended. If the last command was
930 not a kill, a new kill ring slot is used.
933 @deftypefun int rl_push_macro_input (char *macro)
934 Cause @var{macro} to be inserted into the line, as if it had been invoked
935 by a key bound to a macro. Not especially useful; use
936 @code{rl_insert_text()} instead.
939 @node Character Input
940 @subsection Character Input
942 @deftypefun int rl_read_key (void)
943 Return the next character available from Readline's current input stream.
944 This handles input inserted into
945 the input stream via @var{rl_pending_input} (@pxref{Readline Variables})
946 and @code{rl_stuff_char()}, macros, and characters read from the keyboard.
947 While waiting for input, this function will call any function assigned to
948 the @code{rl_event_hook} variable.
951 @deftypefun int rl_getc (FILE *stream)
952 Return the next character available from @var{stream}, which is assumed to
956 @deftypefun int rl_stuff_char (int c)
957 Insert @var{c} into the Readline input stream. It will be "read"
958 before Readline attempts to read characters from the terminal with
959 @code{rl_read_key()}. Up to 512 characters may be pushed back.
960 @code{rl_stuff_char} returns 1 if the character was successfully inserted;
964 @deftypefun int rl_execute_next (int c)
965 Make @var{c} be the next command to be executed when @code{rl_read_key()}
966 is called. This sets @var{rl_pending_input}.
969 @deftypefun int rl_clear_pending_input (void)
970 Unset @var{rl_pending_input}, effectively negating the effect of any
971 previous call to @code{rl_execute_next()}. This works only if the
972 pending input has not already been read with @code{rl_read_key()}.
975 @deftypefun int rl_set_keyboard_input_timeout (int u)
976 While waiting for keyboard input in @code{rl_read_key()}, Readline will
977 wait for @var{u} microseconds for input before calling any function
978 assigned to @code{rl_event_hook}. The default waiting period is
979 one-tenth of a second. Returns the old timeout value.
982 @node Terminal Management
983 @subsection Terminal Management
985 @deftypefun void rl_prep_terminal (int meta_flag)
986 Modify the terminal settings for Readline's use, so @code{readline()}
987 can read a single character at a time from the keyboard.
988 The @var{meta_flag} argument should be non-zero if Readline should
989 read eight-bit input.
992 @deftypefun void rl_deprep_terminal (void)
993 Undo the effects of @code{rl_prep_terminal()}, leaving the terminal in
994 the state in which it was before the most recent call to
995 @code{rl_prep_terminal()}.
998 @deftypefun void rl_tty_set_default_bindings (Keymap kmap)
999 Read the operating system's terminal editing characters (as would be displayed
1000 by @code{stty}) to their Readline equivalents. The bindings are performed
1004 @deftypefun int rl_reset_terminal (const char *terminal_name)
1005 Reinitialize Readline's idea of the terminal settings using
1006 @var{terminal_name} as the terminal type (e.g., @code{vt100}).
1007 If @var{terminal_name} is @code{NULL}, the value of the @code{TERM}
1008 environment variable is used.
1011 @node Utility Functions
1012 @subsection Utility Functions
1014 @deftypefun void rl_replace_line (const char *text, int clear_undo)
1015 Replace the contents of @code{rl_line_buffer} with @var{text}.
1016 The point and mark are preserved, if possible.
1017 If @var{clear_undo} is non-zero, the undo list associated with the
1018 current line is cleared.
1021 @deftypefun int rl_extend_line_buffer (int len)
1022 Ensure that @code{rl_line_buffer} has enough space to hold @var{len}
1023 characters, possibly reallocating it if necessary.
1026 @deftypefun int rl_initialize (void)
1027 Initialize or re-initialize Readline's internal state.
1028 It's not strictly necessary to call this; @code{readline()} calls it before
1032 @deftypefun int rl_ding (void)
1033 Ring the terminal bell, obeying the setting of @code{bell-style}.
1036 @deftypefun int rl_alphabetic (int c)
1037 Return 1 if @var{c} is an alphabetic character.
1040 @deftypefun void rl_display_match_list (char **matches, int len, int max)
1041 A convenience function for displaying a list of strings in
1042 columnar format on Readline's output stream. @code{matches} is the list
1043 of strings, in argv format, such as a list of completion matches.
1044 @code{len} is the number of strings in @code{matches}, and @code{max}
1045 is the length of the longest string in @code{matches}. This function uses
1046 the setting of @code{print-completions-horizontally} to select how the
1047 matches are displayed (@pxref{Readline Init File Syntax}).
1050 The following are implemented as macros, defined in @code{chardefs.h}.
1051 Applications should refrain from using them.
1053 @deftypefun int _rl_uppercase_p (int c)
1054 Return 1 if @var{c} is an uppercase alphabetic character.
1057 @deftypefun int _rl_lowercase_p (int c)
1058 Return 1 if @var{c} is a lowercase alphabetic character.
1061 @deftypefun int _rl_digit_p (int c)
1062 Return 1 if @var{c} is a numeric character.
1065 @deftypefun int _rl_to_upper (int c)
1066 If @var{c} is a lowercase alphabetic character, return the corresponding
1067 uppercase character.
1070 @deftypefun int _rl_to_lower (int c)
1071 If @var{c} is an uppercase alphabetic character, return the corresponding
1072 lowercase character.
1075 @deftypefun int _rl_digit_value (int c)
1076 If @var{c} is a number, return the value it represents.
1079 @node Miscellaneous Functions
1080 @subsection Miscellaneous Functions
1082 @deftypefun int rl_macro_bind (const char *keyseq, const char *macro, Keymap map)
1083 Bind the key sequence @var{keyseq} to invoke the macro @var{macro}.
1084 The binding is performed in @var{map}. When @var{keyseq} is invoked, the
1085 @var{macro} will be inserted into the line. This function is deprecated;
1086 use @code{rl_generic_bind()} instead.
1089 @deftypefun void rl_macro_dumper (int readable)
1090 Print the key sequences bound to macros and their values, using
1091 the current keymap, to @code{rl_outstream}.
1092 If @var{readable} is non-zero, the list is formatted in such a way
1093 that it can be made part of an @code{inputrc} file and re-read.
1096 @deftypefun int rl_variable_bind (const char *variable, const char *value)
1097 Make the Readline variable @var{variable} have @var{value}.
1098 This behaves as if the readline command
1099 @samp{set @var{variable} @var{value}} had been executed in an @code{inputrc}
1100 file (@pxref{Readline Init File Syntax}).
1103 @deftypefun void rl_variable_dumper (int readable)
1104 Print the readline variable names and their current values
1105 to @code{rl_outstream}.
1106 If @var{readable} is non-zero, the list is formatted in such a way
1107 that it can be made part of an @code{inputrc} file and re-read.
1110 @deftypefun int rl_set_paren_blink_timeout (int u)
1111 Set the time interval (in microseconds) that Readline waits when showing
1112 a balancing character when @code{blink-matching-paren} has been enabled.
1115 @deftypefun {char *} rl_get_termcap (const char *cap)
1116 Retrieve the string value of the termcap capability @var{cap}.
1117 Readline fetches the termcap entry for the current terminal name and
1118 uses those capabilities to move around the screen line and perform other
1119 terminal-specific operations, like erasing a line. Readline does not
1120 use all of a terminal's capabilities, and this function will return
1121 values for only those capabilities Readline uses.
1124 @node Alternate Interface
1125 @subsection Alternate Interface
1127 An alternate interface is available to plain @code{readline()}. Some
1128 applications need to interleave keyboard I/O with file, device, or
1129 window system I/O, typically by using a main loop to @code{select()}
1130 on various file descriptors. To accomodate this need, readline can
1131 also be invoked as a `callback' function from an event loop. There
1132 are functions available to make this easy.
1134 @deftypefun void rl_callback_handler_install (const char *prompt, rl_vcpfunc_t *lhandler)
1135 Set up the terminal for readline I/O and display the initial
1136 expanded value of @var{prompt}. Save the value of @var{lhandler} to
1137 use as a function to call when a complete line of input has been entered.
1138 The function takes the text of the line as an argument.
1141 @deftypefun void rl_callback_read_char (void)
1142 Whenever an application determines that keyboard input is available, it
1143 should call @code{rl_callback_read_char()}, which will read the next
1144 character from the current input source.
1145 If that character completes the line, @code{rl_callback_read_char} will
1146 invoke the @var{lhandler} function saved by @code{rl_callback_handler_install}
1147 to process the line.
1148 Before calling the @var{lhandler} function, the terminal settings are
1149 reset to the values they had before calling
1150 @code{rl_callback_handler_install}.
1151 If the @var{lhandler} function returns,
1152 the terminal settings are modified for Readline's use again.
1153 @code{EOF} is indicated by calling @var{lhandler} with a
1157 @deftypefun void rl_callback_handler_remove (void)
1158 Restore the terminal to its initial state and remove the line handler.
1159 This may be called from within a callback as well as independently.
1160 If the @var{lhandler} installed by @code{rl_callback_handler_install}
1161 does not exit the program, either this function or the function referred
1162 to by the value of @code{rl_deprep_term_function} should be called before
1163 the program exits to reset the terminal settings.
1166 @node A Readline Example
1167 @subsection A Readline Example
1169 Here is a function which changes lowercase characters to their uppercase
1170 equivalents, and uppercase characters to lowercase. If
1171 this function was bound to @samp{M-c}, then typing @samp{M-c} would
1172 change the case of the character under point. Typing @samp{M-1 0 M-c}
1173 would change the case of the following 10 characters, leaving the cursor on
1174 the last character changed.
1177 /* Invert the case of the COUNT following characters. */
1179 invert_case_line (count, key)
1182 register int start, end, i;
1186 if (rl_point >= rl_end)
1197 /* Find the end of the range to modify. */
1198 end = start + (count * direction);
1200 /* Force it to be within range. */
1216 /* Tell readline that we are modifying the line,
1217 so it will save the undo information. */
1218 rl_modifying (start, end);
1220 for (i = start; i != end; i++)
1222 if (_rl_uppercase_p (rl_line_buffer[i]))
1223 rl_line_buffer[i] = _rl_to_lower (rl_line_buffer[i]);
1224 else if (_rl_lowercase_p (rl_line_buffer[i]))
1225 rl_line_buffer[i] = _rl_to_upper (rl_line_buffer[i]);
1227 /* Move point to on top of the last character changed. */
1228 rl_point = (direction == 1) ? end - 1 : start;
1233 @node Readline Signal Handling
1234 @section Readline Signal Handling
1236 Signals are asynchronous events sent to a process by the Unix kernel,
1237 sometimes on behalf of another process. They are intended to indicate
1238 exceptional events, like a user pressing the interrupt key on his terminal,
1239 or a network connection being broken. There is a class of signals that can
1240 be sent to the process currently reading input from the keyboard. Since
1241 Readline changes the terminal attributes when it is called, it needs to
1242 perform special processing when such a signal is received in order to
1243 restore the terminal to a sane state, or provide application writers with
1244 functions to do so manually.
1246 Readline contains an internal signal handler that is installed for a
1247 number of signals (@code{SIGINT}, @code{SIGQUIT}, @code{SIGTERM},
1248 @code{SIGALRM}, @code{SIGTSTP}, @code{SIGTTIN}, and @code{SIGTTOU}).
1249 When one of these signals is received, the signal handler
1250 will reset the terminal attributes to those that were in effect before
1251 @code{readline()} was called, reset the signal handling to what it was
1252 before @code{readline()} was called, and resend the signal to the calling
1254 If and when the calling application's signal handler returns, Readline
1255 will reinitialize the terminal and continue to accept input.
1256 When a @code{SIGINT} is received, the Readline signal handler performs
1257 some additional work, which will cause any partially-entered line to be
1258 aborted (see the description of @code{rl_free_line_state()} below).
1260 There is an additional Readline signal handler, for @code{SIGWINCH}, which
1261 the kernel sends to a process whenever the terminal's size changes (for
1262 example, if a user resizes an @code{xterm}). The Readline @code{SIGWINCH}
1263 handler updates Readline's internal screen size information, and then calls
1264 any @code{SIGWINCH} signal handler the calling application has installed.
1265 Readline calls the application's @code{SIGWINCH} signal handler without
1266 resetting the terminal to its original state. If the application's signal
1267 handler does more than update its idea of the terminal size and return (for
1268 example, a @code{longjmp} back to a main processing loop), it @emph{must}
1269 call @code{rl_cleanup_after_signal()} (described below), to restore the
1272 Readline provides two variables that allow application writers to
1273 control whether or not it will catch certain signals and act on them
1274 when they are received. It is important that applications change the
1275 values of these variables only when calling @code{readline()}, not in
1276 a signal handler, so Readline's internal signal state is not corrupted.
1278 @deftypevar int rl_catch_signals
1279 If this variable is non-zero, Readline will install signal handlers for
1280 @code{SIGINT}, @code{SIGQUIT}, @code{SIGTERM}, @code{SIGALRM},
1281 @code{SIGTSTP}, @code{SIGTTIN}, and @code{SIGTTOU}.
1283 The default value of @code{rl_catch_signals} is 1.
1286 @deftypevar int rl_catch_sigwinch
1287 If this variable is non-zero, Readline will install a signal handler for
1290 The default value of @code{rl_catch_sigwinch} is 1.
1293 If an application does not wish to have Readline catch any signals, or
1294 to handle signals other than those Readline catches (@code{SIGHUP},
1296 Readline provides convenience functions to do the necessary terminal
1297 and internal state cleanup upon receipt of a signal.
1299 @deftypefun void rl_cleanup_after_signal (void)
1300 This function will reset the state of the terminal to what it was before
1301 @code{readline()} was called, and remove the Readline signal handlers for
1302 all signals, depending on the values of @code{rl_catch_signals} and
1303 @code{rl_catch_sigwinch}.
1306 @deftypefun void rl_free_line_state (void)
1307 This will free any partial state associated with the current input line
1308 (undo information, any partial history entry, any partially-entered
1309 keyboard macro, and any partially-entered numeric argument). This
1310 should be called before @code{rl_cleanup_after_signal()}. The
1311 Readline signal handler for @code{SIGINT} calls this to abort the
1315 @deftypefun void rl_reset_after_signal (void)
1316 This will reinitialize the terminal and reinstall any Readline signal
1317 handlers, depending on the values of @code{rl_catch_signals} and
1318 @code{rl_catch_sigwinch}.
1321 If an application does not wish Readline to catch @code{SIGWINCH}, it may
1322 call @code{rl_resize_terminal()} or @code{rl_set_screen_size()} to force
1323 Readline to update its idea of the terminal size when a @code{SIGWINCH}
1326 @deftypefun void rl_resize_terminal (void)
1327 Update Readline's internal screen size by reading values from the kernel.
1330 @deftypefun void rl_set_screen_size (int rows, int cols)
1331 Set Readline's idea of the terminal size to @var{rows} rows and
1335 If an application does not want to install a @code{SIGWINCH} handler, but
1336 is still interested in the screen dimensions, Readline's idea of the screen
1337 size may be queried.
1339 @deftypefun void rl_get_screen_size (int *rows, int *cols)
1340 Return Readline's idea of the terminal's size in the
1341 variables pointed to by the arguments.
1344 The following functions install and remove Readline's signal handlers.
1346 @deftypefun int rl_set_signals (void)
1347 Install Readline's signal handler for @code{SIGINT}, @code{SIGQUIT},
1348 @code{SIGTERM}, @code{SIGALRM}, @code{SIGTSTP}, @code{SIGTTIN},
1349 @code{SIGTTOU}, and @code{SIGWINCH}, depending on the values of
1350 @code{rl_catch_signals} and @code{rl_catch_sigwinch}.
1353 @deftypefun int rl_clear_signals (void)
1354 Remove all of the Readline signal handlers installed by
1355 @code{rl_set_signals()}.
1358 @node Custom Completers
1359 @section Custom Completers
1361 Typically, a program that reads commands from the user has a way of
1362 disambiguating commands and data. If your program is one of these, then
1363 it can provide completion for commands, data, or both.
1364 The following sections describe how your program and Readline
1365 cooperate to provide this service.
1368 * How Completing Works:: The logic used to do completion.
1369 * Completion Functions:: Functions provided by Readline.
1370 * Completion Variables:: Variables which control completion.
1371 * A Short Completion Example:: An example of writing completer subroutines.
1374 @node How Completing Works
1375 @subsection How Completing Works
1377 In order to complete some text, the full list of possible completions
1378 must be available. That is, it is not possible to accurately
1379 expand a partial word without knowing all of the possible words
1380 which make sense in that context. The Readline library provides
1381 the user interface to completion, and two of the most common
1382 completion functions: filename and username. For completing other types
1383 of text, you must write your own completion function. This section
1384 describes exactly what such functions must do, and provides an example.
1386 There are three major functions used to perform completion:
1390 The user-interface function @code{rl_complete()}. This function is
1391 called with the same arguments as other bindable Readline functions:
1392 @var{count} and @var{invoking_key}.
1393 It isolates the word to be completed and calls
1394 @code{rl_completion_matches()} to generate a list of possible completions.
1395 It then either lists the possible completions, inserts the possible
1396 completions, or actually performs the
1397 completion, depending on which behavior is desired.
1400 The internal function @code{rl_completion_matches()} uses an
1401 application-supplied @dfn{generator} function to generate the list of
1402 possible matches, and then returns the array of these matches.
1403 The caller should place the address of its generator function in
1404 @code{rl_completion_entry_function}.
1407 The generator function is called repeatedly from
1408 @code{rl_completion_matches()}, returning a string each time. The
1409 arguments to the generator function are @var{text} and @var{state}.
1410 @var{text} is the partial word to be completed. @var{state} is zero the
1411 first time the function is called, allowing the generator to perform
1412 any necessary initialization, and a positive non-zero integer for
1413 each subsequent call. The generator function returns
1414 @code{(char *)NULL} to inform @code{rl_completion_matches()} that there are
1415 no more possibilities left. Usually the generator function computes the
1416 list of possible completions when @var{state} is zero, and returns them
1417 one at a time on subsequent calls. Each string the generator function
1418 returns as a match must be allocated with @code{malloc()}; Readline
1419 frees the strings when it has finished with them.
1423 @deftypefun int rl_complete (int ignore, int invoking_key)
1424 Complete the word at or before point. You have supplied the function
1425 that does the initial simple matching selection algorithm (see
1426 @code{rl_completion_matches()}). The default is to do filename completion.
1429 @deftypevar {rl_compentry_func_t *} rl_completion_entry_function
1430 This is a pointer to the generator function for
1431 @code{rl_completion_matches()}.
1432 If the value of @code{rl_completion_entry_function} is
1433 @code{NULL} then the default filename generator
1434 function, @code{rl_filename_completion_function()}, is used.
1437 @node Completion Functions
1438 @subsection Completion Functions
1440 Here is the complete list of callable completion functions present in
1443 @deftypefun int rl_complete_internal (int what_to_do)
1444 Complete the word at or before point. @var{what_to_do} says what to do
1445 with the completion. A value of @samp{?} means list the possible
1446 completions. @samp{TAB} means do standard completion. @samp{*} means
1447 insert all of the possible completions. @samp{!} means to display
1448 all of the possible completions, if there is more than one, as well as
1449 performing partial completion.
1452 @deftypefun int rl_complete (int ignore, int invoking_key)
1453 Complete the word at or before point. You have supplied the function
1454 that does the initial simple matching selection algorithm (see
1455 @code{rl_completion_matches()} and @code{rl_completion_entry_function}).
1456 The default is to do filename
1457 completion. This calls @code{rl_complete_internal()} with an
1458 argument depending on @var{invoking_key}.
1461 @deftypefun int rl_possible_completions (int count, int invoking_key)
1462 List the possible completions. See description of @code{rl_complete
1463 ()}. This calls @code{rl_complete_internal()} with an argument of
1467 @deftypefun int rl_insert_completions (int count, int invoking_key)
1468 Insert the list of possible completions into the line, deleting the
1469 partially-completed word. See description of @code{rl_complete()}.
1470 This calls @code{rl_complete_internal()} with an argument of @samp{*}.
1473 @deftypefun int rl_completion_mode (rl_command_func_t *cfunc)
1474 Returns the apppriate value to pass to @code{rl_complete_internal()}
1475 depending on whether @var{cfunc} was called twice in succession and
1476 the value of the @code{show-all-if-ambiguous} variable.
1477 Application-specific completion functions may use this function to present
1478 the same interface as @code{rl_complete()}.
1481 @deftypefun {char **} rl_completion_matches (const char *text, rl_compentry_func_t *entry_func)
1482 Returns an array of strings which is a list of completions for
1483 @var{text}. If there are no completions, returns @code{NULL}.
1484 The first entry in the returned array is the substitution for @var{text}.
1485 The remaining entries are the possible completions. The array is
1486 terminated with a @code{NULL} pointer.
1488 @var{entry_func} is a function of two args, and returns a
1489 @code{char *}. The first argument is @var{text}. The second is a
1490 state argument; it is zero on the first call, and non-zero on subsequent
1491 calls. @var{entry_func} returns a @code{NULL} pointer to the caller
1492 when there are no more matches.
1495 @deftypefun {char *} rl_filename_completion_function (const char *text, int state)
1496 A generator function for filename completion in the general case.
1497 @var{text} is a partial filename.
1498 The Bash source is a useful reference for writing custom
1499 completion functions (the Bash completion functions call this and other
1500 Readline functions).
1503 @deftypefun {char *} rl_username_completion_function (const char *text, int state)
1504 A completion generator for usernames. @var{text} contains a partial
1505 username preceded by a random character (usually @samp{~}). As with all
1506 completion generators, @var{state} is zero on the first call and non-zero
1507 for subsequent calls.
1510 @node Completion Variables
1511 @subsection Completion Variables
1513 @deftypevar {rl_compentry_func_t *} rl_completion_entry_function
1514 A pointer to the generator function for @code{rl_completion_matches()}.
1515 @code{NULL} means to use @code{rl_filename_completion_function()}, the default
1519 @deftypevar {rl_completion_func_t *} rl_attempted_completion_function
1520 A pointer to an alternative function to create matches.
1521 The function is called with @var{text}, @var{start}, and @var{end}.
1522 @var{start} and @var{end} are indices in @code{rl_line_buffer} defining
1523 the boundaries of @var{text}, which is a character string.
1524 If this function exists and returns @code{NULL}, or if this variable is
1525 set to @code{NULL}, then @code{rl_complete()} will call the value of
1526 @code{rl_completion_entry_function} to generate matches, otherwise the
1527 array of strings returned will be used.
1528 If this function sets the @code{rl_attempted_completion_over}
1529 variable to a non-zero value, Readline will not perform its default
1530 completion even if this function returns no matches.
1533 @deftypevar {rl_quote_func_t *} rl_filename_quoting_function
1534 A pointer to a function that will quote a filename in an
1535 application-specific fashion. This is called if filename completion is being
1536 attempted and one of the characters in @code{rl_filename_quote_characters}
1537 appears in a completed filename. The function is called with
1538 @var{text}, @var{match_type}, and @var{quote_pointer}. The @var{text}
1539 is the filename to be quoted. The @var{match_type} is either
1540 @code{SINGLE_MATCH}, if there is only one completion match, or
1541 @code{MULT_MATCH}. Some functions use this to decide whether or not to
1542 insert a closing quote character. The @var{quote_pointer} is a pointer
1543 to any opening quote character the user typed. Some functions choose
1544 to reset this character.
1547 @deftypevar {rl_dequote_func_t *} rl_filename_dequoting_function
1548 A pointer to a function that will remove application-specific quoting
1549 characters from a filename before completion is attempted, so those
1550 characters do not interfere with matching the text against names in
1551 the filesystem. It is called with @var{text}, the text of the word
1552 to be dequoted, and @var{quote_char}, which is the quoting character
1553 that delimits the filename (usually @samp{'} or @samp{"}). If
1554 @var{quote_char} is zero, the filename was not in an embedded string.
1557 @deftypevar {rl_linebuf_func_t *} rl_char_is_quoted_p
1558 A pointer to a function to call that determines whether or not a specific
1559 character in the line buffer is quoted, according to whatever quoting
1560 mechanism the program calling Readline uses. The function is called with
1561 two arguments: @var{text}, the text of the line, and @var{index}, the
1562 index of the character in the line. It is used to decide whether a
1563 character found in @code{rl_completer_word_break_characters} should be
1564 used to break words for the completer.
1567 @deftypevar {rl_compignore_func_t *} rl_ignore_some_completions_function
1568 This function, if defined, is called by the completer when real filename
1569 completion is done, after all the matching names have been generated.
1570 It is passed a @code{NULL} terminated array of matches.
1571 The first element (@code{matches[0]}) is the
1572 maximal substring common to all matches. This function can
1573 re-arrange the list of matches as required, but each element deleted
1574 from the array must be freed.
1577 @deftypevar {rl_icppfunc_t *} rl_directory_completion_hook
1578 This function, if defined, is allowed to modify the directory portion
1579 of filenames Readline completes. It is called with the address of a
1580 string (the current directory name) as an argument, and may modify that string.
1581 If the string is replaced with a new string, the old value should be freed.
1582 Any modified directory name should have a trailing slash.
1583 The modified value will be displayed as part of the completion, replacing
1584 the directory portion of the pathname the user typed.
1585 It returns an integer that should be non-zero if the function modifies
1586 its directory argument.
1587 It could be used to expand symbolic links or shell variables in pathnames.
1590 @deftypevar {rl_compdisp_func_t *} rl_completion_display_matches_hook
1591 If non-zero, then this is the address of a function to call when
1592 completing a word would normally display the list of possible matches.
1593 This function is called in lieu of Readline displaying the list.
1594 It takes three arguments:
1595 (@code{char **}@var{matches}, @code{int} @var{num_matches}, @code{int} @var{max_length})
1596 where @var{matches} is the array of matching strings,
1597 @var{num_matches} is the number of strings in that array, and
1598 @var{max_length} is the length of the longest string in that array.
1599 Readline provides a convenience function, @code{rl_display_match_list},
1600 that takes care of doing the display to Readline's output stream. That
1601 function may be called from this hook.
1604 @deftypevar {const char *} rl_basic_word_break_characters
1605 The basic list of characters that signal a break between words for the
1606 completer routine. The default value of this variable is the characters
1607 which break words for completion in Bash:
1608 @code{" \t\n\"\\'`@@$><=;|&@{("}.
1611 @deftypevar {const char *} rl_basic_quote_characters
1612 A list of quote characters which can cause a word break.
1615 @deftypevar {const char *} rl_completer_word_break_characters
1616 The list of characters that signal a break between words for
1617 @code{rl_complete_internal()}. The default list is the value of
1618 @code{rl_basic_word_break_characters}.
1621 @deftypevar {const char *} rl_completer_quote_characters
1622 A list of characters which can be used to quote a substring of the line.
1623 Completion occurs on the entire substring, and within the substring
1624 @code{rl_completer_word_break_characters} are treated as any other character,
1625 unless they also appear within this list.
1628 @deftypevar {const char *} rl_filename_quote_characters
1629 A list of characters that cause a filename to be quoted by the completer
1630 when they appear in a completed filename. The default is the null string.
1633 @deftypevar {const char *} rl_special_prefixes
1634 The list of characters that are word break characters, but should be
1635 left in @var{text} when it is passed to the completion function.
1636 Programs can use this to help determine what kind of completing to do.
1637 For instance, Bash sets this variable to "$@@" so that it can complete
1638 shell variables and hostnames.
1641 @deftypevar int rl_completion_query_items
1642 Up to this many items will be displayed in response to a
1643 possible-completions call. After that, we ask the user if she is sure
1644 she wants to see them all. The default value is 100.
1647 @deftypevar {int} rl_completion_append_character
1648 When a single completion alternative matches at the end of the command
1649 line, this character is appended to the inserted completion text. The
1650 default is a space character (@samp{ }). Setting this to the null
1651 character (@samp{\0}) prevents anything being appended automatically.
1652 This can be changed in custom completion functions to
1653 provide the ``most sensible word separator character'' according to
1654 an application-specific command line syntax specification.
1657 @deftypevar int rl_completion_suppress_append
1658 If non-zero, @var{rl_completion_append_character} is not appended to
1659 matches at the end of the command line, as described above. It is
1660 set to 0 before any application-specific completion function is called.
1663 @deftypevar int rl_completion_mark_symlink_dirs
1664 If non-zero, a slash will be appended to completed filenames that are
1665 symbolic links to directory names, subject to the value of the
1666 user-settable @var{mark-directories} variable.
1667 This variable exists so that application completion functions can
1668 override the user's global preference (set via the
1669 @var{mark-symlinked-directories} Readline variable) if appropriate.
1670 This variable is set to the user's preference before any
1671 application completion function is called, so unless that function
1672 modifies the value, the user's preferences are honored.
1675 @deftypevar int rl_ignore_completion_duplicates
1676 If non-zero, then duplicates in the matches are removed.
1680 @deftypevar int rl_filename_completion_desired
1681 Non-zero means that the results of the matches are to be treated as
1682 filenames. This is @emph{always} zero on entry, and can only be changed
1683 within a completion entry generator function. If it is set to a non-zero
1684 value, directory names have a slash appended and Readline attempts to
1685 quote completed filenames if they contain any characters in
1686 @code{rl_filename_quote_characters} and @code{rl_filename_quoting_desired}
1687 is set to a non-zero value.
1690 @deftypevar int rl_filename_quoting_desired
1691 Non-zero means that the results of the matches are to be quoted using
1692 double quotes (or an application-specific quoting mechanism) if the
1693 completed filename contains any characters in
1694 @code{rl_filename_quote_chars}. This is @emph{always} non-zero
1695 on entry, and can only be changed within a completion entry generator
1696 function. The quoting is effected via a call to the function pointed to
1697 by @code{rl_filename_quoting_function}.
1700 @deftypevar int rl_attempted_completion_over
1701 If an application-specific completion function assigned to
1702 @code{rl_attempted_completion_function} sets this variable to a non-zero
1703 value, Readline will not perform its default filename completion even
1704 if the application's completion function returns no matches.
1705 It should be set only by an application's completion function.
1708 @deftypevar int rl_completion_type
1709 Set to a character describing the type of completion Readline is currently
1710 attempting; see the description of @code{rl_complete_internal()}
1711 (@pxref{Completion Functions}) for the list of characters.
1714 @deftypevar int rl_inhibit_completion
1715 If this variable is non-zero, completion is inhibited. The completion
1716 character will be inserted as any other bound to @code{self-insert}.
1719 @node A Short Completion Example
1720 @subsection A Short Completion Example
1722 Here is a small application demonstrating the use of the GNU Readline
1723 library. It is called @code{fileman}, and the source code resides in
1724 @file{examples/fileman.c}. This sample application provides
1725 completion of command names, line editing features, and access to the
1730 /* fileman.c -- A tiny application which demonstrates how to use the
1731 GNU Readline library. This application interactively allows users
1732 to manipulate files and their modes. */
1735 #include <sys/types.h>
1736 #include <sys/file.h>
1737 #include <sys/stat.h>
1738 #include <sys/errno.h>
1740 #include <readline/readline.h>
1741 #include <readline/history.h>
1743 extern char *xmalloc ();
1745 /* The names of functions that actually do the manipulation. */
1746 int com_list __P((char *));
1747 int com_view __P((char *));
1748 int com_rename __P((char *));
1749 int com_stat __P((char *));
1750 int com_pwd __P((char *));
1751 int com_delete __P((char *));
1752 int com_help __P((char *));
1753 int com_cd __P((char *));
1754 int com_quit __P((char *));
1756 /* A structure which contains information on the commands this program
1760 char *name; /* User printable name of the function. */
1761 rl_icpfunc_t *func; /* Function to call to do the job. */
1762 char *doc; /* Documentation for this function. */
1765 COMMAND commands[] = @{
1766 @{ "cd", com_cd, "Change to directory DIR" @},
1767 @{ "delete", com_delete, "Delete FILE" @},
1768 @{ "help", com_help, "Display this text" @},
1769 @{ "?", com_help, "Synonym for `help'" @},
1770 @{ "list", com_list, "List files in DIR" @},
1771 @{ "ls", com_list, "Synonym for `list'" @},
1772 @{ "pwd", com_pwd, "Print the current working directory" @},
1773 @{ "quit", com_quit, "Quit using Fileman" @},
1774 @{ "rename", com_rename, "Rename FILE to NEWNAME" @},
1775 @{ "stat", com_stat, "Print out statistics on FILE" @},
1776 @{ "view", com_view, "View the contents of FILE" @},
1777 @{ (char *)NULL, (rl_icpfunc_t *)NULL, (char *)NULL @}
1780 /* Forward declarations. */
1781 char *stripwhite ();
1782 COMMAND *find_command ();
1784 /* The name of this program, as taken from argv[0]. */
1787 /* When non-zero, this means the user is done using this program. */
1796 r = xmalloc (strlen (s) + 1);
1809 initialize_readline (); /* Bind our completer. */
1811 /* Loop reading and executing lines until the user quits. */
1812 for ( ; done == 0; )
1814 line = readline ("FileMan: ");
1819 /* Remove leading and trailing whitespace from the line.
1820 Then, if there is anything left, add it to the history list
1822 s = stripwhite (line);
1835 /* Execute a command line. */
1844 /* Isolate the command word. */
1846 while (line[i] && whitespace (line[i]))
1850 while (line[i] && !whitespace (line[i]))
1856 command = find_command (word);
1860 fprintf (stderr, "%s: No such command for FileMan.\n", word);
1864 /* Get argument to command, if any. */
1865 while (whitespace (line[i]))
1870 /* Call the function. */
1871 return ((*(command->func)) (word));
1874 /* Look up NAME as the name of a command, and return a pointer to that
1875 command. Return a NULL pointer if NAME isn't a command name. */
1882 for (i = 0; commands[i].name; i++)
1883 if (strcmp (name, commands[i].name) == 0)
1884 return (&commands[i]);
1886 return ((COMMAND *)NULL);
1889 /* Strip whitespace from the start and end of STRING. Return a pointer
1895 register char *s, *t;
1897 for (s = string; whitespace (*s); s++)
1903 t = s + strlen (s) - 1;
1904 while (t > s && whitespace (*t))
1911 /* **************************************************************** */
1913 /* Interface to Readline Completion */
1915 /* **************************************************************** */
1917 char *command_generator __P((const char *, int));
1918 char **fileman_completion __P((const char *, int, int));
1920 /* Tell the GNU Readline library how to complete. We want to try to
1921 complete on command names if this is the first word in the line, or
1922 on filenames if not. */
1923 initialize_readline ()
1925 /* Allow conditional parsing of the ~/.inputrc file. */
1926 rl_readline_name = "FileMan";
1928 /* Tell the completer that we want a crack first. */
1929 rl_attempted_completion_function = fileman_completion;
1932 /* Attempt to complete on the contents of TEXT. START and END
1933 bound the region of rl_line_buffer that contains the word to
1934 complete. TEXT is the word to complete. We can use the entire
1935 contents of rl_line_buffer in case we want to do some simple
1936 parsing. Returnthe array of matches, or NULL if there aren't any. */
1938 fileman_completion (text, start, end)
1944 matches = (char **)NULL;
1946 /* If this word is at the start of the line, then it is a command
1947 to complete. Otherwise it is the name of a file in the current
1950 matches = rl_completion_matches (text, command_generator);
1955 /* Generator function for command completion. STATE lets us
1956 know whether to start from scratch; without any state
1957 (i.e. STATE == 0), then we start at the top of the list. */
1959 command_generator (text, state)
1963 static int list_index, len;
1966 /* If this is a new word to complete, initialize now. This
1967 includes saving the length of TEXT for efficiency, and
1968 initializing the index variable to 0. */
1972 len = strlen (text);
1975 /* Return the next name which partially matches from the
1977 while (name = commands[list_index].name)
1981 if (strncmp (name, text, len) == 0)
1982 return (dupstr(name));
1985 /* If no names matched, then return NULL. */
1986 return ((char *)NULL);
1989 /* **************************************************************** */
1991 /* FileMan Commands */
1993 /* **************************************************************** */
1995 /* String to pass to system (). This is for the LIST, VIEW and RENAME
1997 static char syscom[1024];
1999 /* List the file(s) named in arg. */
2006 sprintf (syscom, "ls -FClg %s", arg);
2007 return (system (syscom));
2013 if (!valid_argument ("view", arg))
2016 sprintf (syscom, "more %s", arg);
2017 return (system (syscom));
2023 too_dangerous ("rename");
2032 if (!valid_argument ("stat", arg))
2035 if (stat (arg, &finfo) == -1)
2041 printf ("Statistics for `%s':\n", arg);
2043 printf ("%s has %d link%s, and is %d byte%s in length.\n", arg,
2045 (finfo.st_nlink == 1) ? "" : "s",
2047 (finfo.st_size == 1) ? "" : "s");
2048 printf ("Inode Last Change at: %s", ctime (&finfo.st_ctime));
2049 printf (" Last access at: %s", ctime (&finfo.st_atime));
2050 printf (" Last modified at: %s", ctime (&finfo.st_mtime));
2057 too_dangerous ("delete");
2061 /* Print out help for ARG, or for all of the commands if ARG is
2069 for (i = 0; commands[i].name; i++)
2071 if (!*arg || (strcmp (arg, commands[i].name) == 0))
2073 printf ("%s\t\t%s.\n", commands[i].name, commands[i].doc);
2080 printf ("No commands match `%s'. Possibilties are:\n", arg);
2082 for (i = 0; commands[i].name; i++)
2084 /* Print in six columns. */
2091 printf ("%s\t", commands[i].name);
2101 /* Change to the directory ARG. */
2105 if (chdir (arg) == -1)
2115 /* Print out the current working directory. */
2121 s = getcwd (dir, sizeof(dir) - 1);
2124 printf ("Error getting pwd: %s\n", dir);
2128 printf ("Current directory is %s\n", dir);
2132 /* The user wishes to quit using this program. Just set DONE
2141 /* Function which tells you that you can't do this. */
2142 too_dangerous (caller)
2146 "%s: Too dangerous for me to distribute.\n"
2148 fprintf (stderr, "Write it yourself.\n");
2151 /* Return non-zero if ARG is a valid argument for CALLER,
2152 else print an error message and return zero. */
2154 valid_argument (caller, arg)
2159 fprintf (stderr, "%s: Argument required.\n", caller);