1 @comment %**start of header (This is for running Texinfo on a region.)
2 @setfilename rltech.info
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6 This document describes the GNU Readline Library, a utility for aiding
7 in the consistency of user interface across discrete programs that need
8 to provide a command line interface.
10 Copyright (C) 1988--2014 Free Software Foundation, Inc.
12 Permission is granted to make and distribute verbatim copies of
13 this manual provided the copyright notice and this permission notice
14 pare preserved on all copies.
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19 notice identical to this one except for the removal of this paragraph
20 (this paragraph not being relevant to the printed manual).
23 Permission is granted to copy and distribute modified versions of this
24 manual under the conditions for verbatim copying, provided that the entire
25 resulting derived work is distributed under the terms of a permission
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28 Permission is granted to copy and distribute translations of this manual
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30 except that this permission notice may be stated in a translation approved
34 @node Programming with GNU Readline
35 @chapter Programming with GNU Readline
37 This chapter describes the interface between the @sc{gnu} Readline Library and
38 other programs. If you are a programmer, and you wish to include the
39 features found in @sc{gnu} Readline
40 such as completion, line editing, and interactive history manipulation
41 in your own programs, this section is for you.
44 * Basic Behavior:: Using the default behavior of Readline.
45 * Custom Functions:: Adding your own functions to Readline.
46 * Readline Variables:: Variables accessible to custom
48 * Readline Convenience Functions:: Functions which Readline supplies to
49 aid in writing your own custom
51 * Readline Signal Handling:: How Readline behaves when it receives signals.
52 * Custom Completers:: Supplanting or supplementing Readline's
57 @section Basic Behavior
59 Many programs provide a command line interface, such as @code{mail},
60 @code{ftp}, and @code{sh}. For such programs, the default behaviour of
61 Readline is sufficient. This section describes how to use Readline in
62 the simplest way possible, perhaps to replace calls in your code to
63 @code{gets()} or @code{fgets()}.
66 @cindex readline, function
68 The function @code{readline()} prints a prompt @var{prompt}
69 and then reads and returns a single line of text from the user.
70 If @var{prompt} is @code{NULL} or the empty string, no prompt is displayed.
71 The line @code{readline} returns is allocated with @code{malloc()};
72 the caller should @code{free()} the line when it has finished with it.
73 The declaration for @code{readline} in ANSI C is
76 @code{char *readline (const char *@var{prompt});}
82 @code{char *line = readline ("Enter a line: ");}
85 in order to read a line of text from the user.
86 The line returned has the final newline removed, so only the
89 If @code{readline} encounters an @code{EOF} while reading the line, and the
90 line is empty at that point, then @code{(char *)NULL} is returned.
91 Otherwise, the line is ended just as if a newline had been typed.
93 If you want the user to be able to get at the line later, (with
94 @key{C-p} for example), you must call @code{add_history()} to save the
95 line away in a @dfn{history} list of such lines.
98 @code{add_history (line)};
102 For full details on the GNU History Library, see the associated manual.
104 It is preferable to avoid saving empty lines on the history list, since
105 users rarely have a burning need to reuse a blank line. Here is
106 a function which usefully replaces the standard @code{gets()} library
107 function, and has the advantage of no static buffer to overflow:
110 /* A static variable for holding the line. */
111 static char *line_read = (char *)NULL;
113 /* Read a string, and return a pointer to it.
114 Returns NULL on EOF. */
118 /* If the buffer has already been allocated,
119 return the memory to the free pool. */
123 line_read = (char *)NULL;
126 /* Get a line from the user. */
127 line_read = readline ("");
129 /* If the line has any text in it,
130 save it on the history. */
131 if (line_read && *line_read)
132 add_history (line_read);
138 This function gives the user the default behaviour of @key{TAB}
139 completion: completion on file names. If you do not want Readline to
140 complete on filenames, you can change the binding of the @key{TAB} key
141 with @code{rl_bind_key()}.
144 @code{int rl_bind_key (int @var{key}, rl_command_func_t *@var{function});}
147 @code{rl_bind_key()} takes two arguments: @var{key} is the character that
148 you want to bind, and @var{function} is the address of the function to
149 call when @var{key} is pressed. Binding @key{TAB} to @code{rl_insert()}
150 makes @key{TAB} insert itself.
151 @code{rl_bind_key()} returns non-zero if @var{key} is not a valid
152 ASCII character code (between 0 and 255).
154 Thus, to disable the default @key{TAB} behavior, the following suffices:
156 @code{rl_bind_key ('\t', rl_insert);}
159 This code should be executed once at the start of your program; you
160 might write a function called @code{initialize_readline()} which
161 performs this and other desired initializations, such as installing
162 custom completers (@pxref{Custom Completers}).
164 @node Custom Functions
165 @section Custom Functions
167 Readline provides many functions for manipulating the text of
168 the line, but it isn't possible to anticipate the needs of all
169 programs. This section describes the various functions and variables
170 defined within the Readline library which allow a user program to add
171 customized functionality to Readline.
173 Before declaring any functions that customize Readline's behavior, or
174 using any functionality Readline provides in other code, an
175 application writer should include the file @code{<readline/readline.h>}
176 in any file that uses Readline's features. Since some of the definitions
177 in @code{readline.h} use the @code{stdio} library, the file
178 @code{<stdio.h>} should be included before @code{readline.h}.
180 @code{readline.h} defines a C preprocessor variable that should
181 be treated as an integer, @code{RL_READLINE_VERSION}, which may
182 be used to conditionally compile application code depending on
183 the installed Readline version. The value is a hexadecimal
184 encoding of the major and minor version numbers of the library,
185 of the form 0x@var{MMmm}. @var{MM} is the two-digit major
186 version number; @var{mm} is the two-digit minor version number.
187 For Readline 4.2, for example, the value of
188 @code{RL_READLINE_VERSION} would be @code{0x0402}.
191 * Readline Typedefs:: C declarations to make code readable.
192 * Function Writing:: Variables and calling conventions.
195 @node Readline Typedefs
196 @subsection Readline Typedefs
198 For readability, we declare a number of new object types, all pointers
201 The reason for declaring these new types is to make it easier to write
202 code describing pointers to C functions with appropriately prototyped
203 arguments and return values.
205 For instance, say we want to declare a variable @var{func} as a pointer
206 to a function which takes two @code{int} arguments and returns an
207 @code{int} (this is the type of all of the Readline bindable functions).
208 Instead of the classic C declaration
210 @code{int (*func)();}
213 or the ANSI-C style declaration
215 @code{int (*func)(int, int);}
220 @code{rl_command_func_t *func;}
222 The full list of function pointer types available is
225 @item typedef int rl_command_func_t (int, int);
227 @item typedef char *rl_compentry_func_t (const char *, int);
229 @item typedef char **rl_completion_func_t (const char *, int, int);
231 @item typedef char *rl_quote_func_t (char *, int, char *);
233 @item typedef char *rl_dequote_func_t (char *, int);
235 @item typedef int rl_compignore_func_t (char **);
237 @item typedef void rl_compdisp_func_t (char **, int, int);
239 @item typedef int rl_hook_func_t (void);
241 @item typedef int rl_getc_func_t (FILE *);
243 @item typedef int rl_linebuf_func_t (char *, int);
245 @item typedef int rl_intfunc_t (int);
246 @item #define rl_ivoidfunc_t rl_hook_func_t
247 @item typedef int rl_icpfunc_t (char *);
248 @item typedef int rl_icppfunc_t (char **);
250 @item typedef void rl_voidfunc_t (void);
251 @item typedef void rl_vintfunc_t (int);
252 @item typedef void rl_vcpfunc_t (char *);
253 @item typedef void rl_vcppfunc_t (char **);
257 @node Function Writing
258 @subsection Writing a New Function
260 In order to write new functions for Readline, you need to know the
261 calling conventions for keyboard-invoked functions, and the names of the
262 variables that describe the current state of the line read so far.
264 The calling sequence for a command @code{foo} looks like
267 @code{int foo (int count, int key)}
271 where @var{count} is the numeric argument (or 1 if defaulted) and
272 @var{key} is the key that invoked this function.
274 It is completely up to the function as to what should be done with the
275 numeric argument. Some functions use it as a repeat count, some
276 as a flag, and others to choose alternate behavior (refreshing the current
277 line as opposed to refreshing the screen, for example). Some choose to
278 ignore it. In general, if a
279 function uses the numeric argument as a repeat count, it should be able
280 to do something useful with both negative and positive arguments.
281 At the very least, it should be aware that it can be passed a
284 A command function should return 0 if its action completes successfully,
285 and a non-zero value if some error occurs.
286 This is the convention obeyed by all of the builtin Readline bindable
289 @node Readline Variables
290 @section Readline Variables
292 These variables are available to function writers.
294 @deftypevar {char *} rl_line_buffer
295 This is the line gathered so far. You are welcome to modify the
296 contents of the line, but see @ref{Allowing Undoing}. The
297 function @code{rl_extend_line_buffer} is available to increase
298 the memory allocated to @code{rl_line_buffer}.
301 @deftypevar int rl_point
302 The offset of the current cursor position in @code{rl_line_buffer}
306 @deftypevar int rl_end
307 The number of characters present in @code{rl_line_buffer}. When
308 @code{rl_point} is at the end of the line, @code{rl_point} and
309 @code{rl_end} are equal.
312 @deftypevar int rl_mark
313 The @var{mark} (saved position) in the current line. If set, the mark
314 and point define a @emph{region}.
317 @deftypevar int rl_done
318 Setting this to a non-zero value causes Readline to return the current
322 @deftypevar int rl_num_chars_to_read
323 Setting this to a positive value before calling @code{readline()} causes
324 Readline to return after accepting that many characters, rather
325 than reading up to a character bound to @code{accept-line}.
328 @deftypevar int rl_pending_input
329 Setting this to a value makes it the next keystroke read. This is a
330 way to stuff a single character into the input stream.
333 @deftypevar int rl_dispatching
334 Set to a non-zero value if a function is being called from a key binding;
335 zero otherwise. Application functions can test this to discover whether
336 they were called directly or by Readline's dispatching mechanism.
339 @deftypevar int rl_erase_empty_line
340 Setting this to a non-zero value causes Readline to completely erase
341 the current line, including any prompt, any time a newline is typed as
342 the only character on an otherwise-empty line. The cursor is moved to
343 the beginning of the newly-blank line.
346 @deftypevar {char *} rl_prompt
347 The prompt Readline uses. This is set from the argument to
348 @code{readline()}, and should not be assigned to directly.
349 The @code{rl_set_prompt()} function (@pxref{Redisplay}) may
350 be used to modify the prompt string after calling @code{readline()}.
353 @deftypevar {char *} rl_display_prompt
354 The string displayed as the prompt. This is usually identical to
355 @var{rl_prompt}, but may be changed temporarily by functions that
356 use the prompt string as a message area, such as incremental search.
359 @deftypevar int rl_already_prompted
360 If an application wishes to display the prompt itself, rather than have
361 Readline do it the first time @code{readline()} is called, it should set
362 this variable to a non-zero value after displaying the prompt.
363 The prompt must also be passed as the argument to @code{readline()} so
364 the redisplay functions can update the display properly.
365 The calling application is responsible for managing the value; Readline
369 @deftypevar {const char *} rl_library_version
370 The version number of this revision of the library.
373 @deftypevar int rl_readline_version
374 An integer encoding the current version of the library. The encoding is
375 of the form 0x@var{MMmm}, where @var{MM} is the two-digit major version
376 number, and @var{mm} is the two-digit minor version number.
377 For example, for Readline-4.2, @code{rl_readline_version} would have the
381 @deftypevar {int} rl_gnu_readline_p
382 Always set to 1, denoting that this is @sc{gnu} readline rather than some
386 @deftypevar {const char *} rl_terminal_name
387 The terminal type, used for initialization. If not set by the application,
388 Readline sets this to the value of the @env{TERM} environment variable
389 the first time it is called.
392 @deftypevar {const char *} rl_readline_name
393 This variable is set to a unique name by each application using Readline.
394 The value allows conditional parsing of the inputrc file
395 (@pxref{Conditional Init Constructs}).
398 @deftypevar {FILE *} rl_instream
399 The stdio stream from which Readline reads input.
400 If @code{NULL}, Readline defaults to @var{stdin}.
403 @deftypevar {FILE *} rl_outstream
404 The stdio stream to which Readline performs output.
405 If @code{NULL}, Readline defaults to @var{stdout}.
408 @deftypevar int rl_prefer_env_winsize
409 If non-zero, Readline gives values found in the @env{LINES} and
410 @env{COLUMNS} environment variables greater precedence than values fetched
411 from the kernel when computing the screen dimensions.
414 @deftypevar {rl_command_func_t *} rl_last_func
415 The address of the last command function Readline executed. May be used to
416 test whether or not a function is being executed twice in succession, for
420 @deftypevar {rl_hook_func_t *} rl_startup_hook
421 If non-zero, this is the address of a function to call just
422 before @code{readline} prints the first prompt.
425 @deftypevar {rl_hook_func_t *} rl_pre_input_hook
426 If non-zero, this is the address of a function to call after
427 the first prompt has been printed and just before @code{readline}
428 starts reading input characters.
431 @deftypevar {rl_hook_func_t *} rl_event_hook
432 If non-zero, this is the address of a function to call periodically
433 when Readline is waiting for terminal input.
434 By default, this will be called at most ten times a second if there
435 is no keyboard input.
438 @deftypevar {rl_getc_func_t *} rl_getc_function
439 If non-zero, Readline will call indirectly through this pointer
440 to get a character from the input stream. By default, it is set to
441 @code{rl_getc}, the default Readline character input function
442 (@pxref{Character Input}).
443 In general, an application that sets @var{rl_getc_function} should consider
444 setting @var{rl_input_available_hook} as well.
447 @deftypevar {rl_hook_func_t *} rl_signal_event_hook
448 If non-zero, this is the address of a function to call if a read system
449 call is interrupted when Readline is reading terminal input.
452 @deftypevar {rl_hook_func_t *} rl_input_available_hook
453 If non-zero, Readline will use this function's return value when it needs
454 to determine whether or not there is available input on the current input
456 The default hook checks @code{rl_instream}; if an application is using a
457 different input source, it should set the hook appropriately.
458 Readline queries for available input when implementing intra-key-sequence
459 timeouts during input and incremental searches.
460 This may use an application-specific timeout before returning a value;
461 Readline uses the value passed to @code{rl_set_keyboard_input_timeout()}
462 or the value of the user-settable @var{keyseq-timeout} variable.
463 This is designed for use by applications using Readline's callback interface
464 (@pxref{Alternate Interface}), which may not use the traditional
465 @code{read(2)} and file descriptor interface, or other applications using
466 a different input mechanism.
467 If an application uses an input mechanism or hook that can potentially exceed
468 the value of @var{keyseq-timeout}, it should increase the timeout or set
469 this hook appropriately even when not using the callback interface.
470 In general, an application that sets @var{rl_getc_function} should consider
471 setting @var{rl_input_available_hook} as well.
474 @deftypevar {rl_voidfunc_t *} rl_redisplay_function
475 If non-zero, Readline will call indirectly through this pointer
476 to update the display with the current contents of the editing buffer.
477 By default, it is set to @code{rl_redisplay}, the default Readline
478 redisplay function (@pxref{Redisplay}).
481 @deftypevar {rl_vintfunc_t *} rl_prep_term_function
482 If non-zero, Readline will call indirectly through this pointer
483 to initialize the terminal. The function takes a single argument, an
484 @code{int} flag that says whether or not to use eight-bit characters.
485 By default, this is set to @code{rl_prep_terminal}
486 (@pxref{Terminal Management}).
489 @deftypevar {rl_voidfunc_t *} rl_deprep_term_function
490 If non-zero, Readline will call indirectly through this pointer
491 to reset the terminal. This function should undo the effects of
492 @code{rl_prep_term_function}.
493 By default, this is set to @code{rl_deprep_terminal}
494 (@pxref{Terminal Management}).
497 @deftypevar {Keymap} rl_executing_keymap
498 This variable is set to the keymap (@pxref{Keymaps}) in which the
499 currently executing readline function was found.
502 @deftypevar {Keymap} rl_binding_keymap
503 This variable is set to the keymap (@pxref{Keymaps}) in which the
504 last key binding occurred.
507 @deftypevar {char *} rl_executing_macro
508 This variable is set to the text of any currently-executing macro.
511 @deftypevar int rl_executing_key
512 The key that caused the dispatch to the currently-executing Readline function.
515 @deftypevar {char *} rl_executing_keyseq
516 The full key sequence that caused the dispatch to the currently-executing
520 @deftypevar int rl_key_sequence_length
521 The number of characters in @var{rl_executing_keyseq}.
524 @deftypevar {int} rl_readline_state
525 A variable with bit values that encapsulate the current Readline state.
526 A bit is set with the @code{RL_SETSTATE} macro, and unset with the
527 @code{RL_UNSETSTATE} macro. Use the @code{RL_ISSTATE} macro to test
528 whether a particular state bit is set. Current state bits include:
532 Readline has not yet been called, nor has it begun to initialize.
533 @item RL_STATE_INITIALIZING
534 Readline is initializing its internal data structures.
535 @item RL_STATE_INITIALIZED
536 Readline has completed its initialization.
537 @item RL_STATE_TERMPREPPED
538 Readline has modified the terminal modes to do its own input and redisplay.
539 @item RL_STATE_READCMD
540 Readline is reading a command from the keyboard.
541 @item RL_STATE_METANEXT
542 Readline is reading more input after reading the meta-prefix character.
543 @item RL_STATE_DISPATCHING
544 Readline is dispatching to a command.
545 @item RL_STATE_MOREINPUT
546 Readline is reading more input while executing an editing command.
547 @item RL_STATE_ISEARCH
548 Readline is performing an incremental history search.
549 @item RL_STATE_NSEARCH
550 Readline is performing a non-incremental history search.
551 @item RL_STATE_SEARCH
552 Readline is searching backward or forward through the history for a string.
553 @item RL_STATE_NUMERICARG
554 Readline is reading a numeric argument.
555 @item RL_STATE_MACROINPUT
556 Readline is currently getting its input from a previously-defined keyboard
558 @item RL_STATE_MACRODEF
559 Readline is currently reading characters defining a keyboard macro.
560 @item RL_STATE_OVERWRITE
561 Readline is in overwrite mode.
562 @item RL_STATE_COMPLETING
563 Readline is performing word completion.
564 @item RL_STATE_SIGHANDLER
565 Readline is currently executing the readline signal handler.
566 @item RL_STATE_UNDOING
567 Readline is performing an undo.
568 @item RL_STATE_INPUTPENDING
569 Readline has input pending due to a call to @code{rl_execute_next()}.
570 @item RL_STATE_TTYCSAVED
571 Readline has saved the values of the terminal's special characters.
572 @item RL_STATE_CALLBACK
573 Readline is currently using the alternate (callback) interface
574 (@pxref{Alternate Interface}).
575 @item RL_STATE_VIMOTION
576 Readline is reading the argument to a vi-mode "motion" command.
577 @item RL_STATE_MULTIKEY
578 Readline is reading a multiple-keystroke command.
579 @item RL_STATE_VICMDONCE
580 Readline has entered vi command (movement) mode at least one time during
581 the current call to @code{readline()}.
583 Readline has read a key sequence bound to @code{accept-line}
584 and is about to return the line to the caller.
589 @deftypevar {int} rl_explicit_arg
590 Set to a non-zero value if an explicit numeric argument was specified by
591 the user. Only valid in a bindable command function.
594 @deftypevar {int} rl_numeric_arg
595 Set to the value of any numeric argument explicitly specified by the user
596 before executing the current Readline function. Only valid in a bindable
600 @deftypevar {int} rl_editing_mode
601 Set to a value denoting Readline's current editing mode. A value of
602 @var{1} means Readline is currently in emacs mode; @var{0}
603 means that vi mode is active.
607 @node Readline Convenience Functions
608 @section Readline Convenience Functions
611 * Function Naming:: How to give a function you write a name.
612 * Keymaps:: Making keymaps.
613 * Binding Keys:: Changing Keymaps.
614 * Associating Function Names and Bindings:: Translate function names to
616 * Allowing Undoing:: How to make your functions undoable.
617 * Redisplay:: Functions to control line display.
618 * Modifying Text:: Functions to modify @code{rl_line_buffer}.
619 * Character Input:: Functions to read keyboard input.
620 * Terminal Management:: Functions to manage terminal settings.
621 * Utility Functions:: Generally useful functions and hooks.
622 * Miscellaneous Functions:: Functions that don't fall into any category.
623 * Alternate Interface:: Using Readline in a `callback' fashion.
624 * A Readline Example:: An example Readline function.
625 * Alternate Interface Example:: An example program using the alternate interface.
628 @node Function Naming
629 @subsection Naming a Function
631 The user can dynamically change the bindings of keys while using
632 Readline. This is done by representing the function with a descriptive
633 name. The user is able to type the descriptive name when referring to
634 the function. Thus, in an init file, one might find
637 Meta-Rubout: backward-kill-word
640 This binds the keystroke @key{Meta-Rubout} to the function
641 @emph{descriptively} named @code{backward-kill-word}. You, as the
642 programmer, should bind the functions you write to descriptive names as
643 well. Readline provides a function for doing that:
645 @deftypefun int rl_add_defun (const char *name, rl_command_func_t *function, int key)
646 Add @var{name} to the list of named functions. Make @var{function} be
647 the function that gets called. If @var{key} is not -1, then bind it to
648 @var{function} using @code{rl_bind_key()}.
651 Using this function alone is sufficient for most applications.
652 It is the recommended way to add a few functions to the default
653 functions that Readline has built in.
654 If you need to do something other than adding a function to Readline,
655 you may need to use the underlying functions described below.
658 @subsection Selecting a Keymap
660 Key bindings take place on a @dfn{keymap}. The keymap is the
661 association between the keys that the user types and the functions that
662 get run. You can make your own keymaps, copy existing keymaps, and tell
663 Readline which keymap to use.
665 @deftypefun Keymap rl_make_bare_keymap (void)
666 Returns a new, empty keymap. The space for the keymap is allocated with
667 @code{malloc()}; the caller should free it by calling
668 @code{rl_free_keymap()} when done.
671 @deftypefun Keymap rl_copy_keymap (Keymap map)
672 Return a new keymap which is a copy of @var{map}.
675 @deftypefun Keymap rl_make_keymap (void)
676 Return a new keymap with the printing characters bound to rl_insert,
677 the lowercase Meta characters bound to run their equivalents, and
678 the Meta digits bound to produce numeric arguments.
681 @deftypefun void rl_discard_keymap (Keymap keymap)
682 Free the storage associated with the data in @var{keymap}.
683 The caller should free @var{keymap}.
686 @deftypefun void rl_free_keymap (Keymap keymap)
687 Free all storage associated with @var{keymap}. This calls
688 @code{rl_discard_keymap} to free subordindate keymaps and macros.
691 Readline has several internal keymaps. These functions allow you to
692 change which keymap is active.
694 @deftypefun Keymap rl_get_keymap (void)
695 Returns the currently active keymap.
698 @deftypefun void rl_set_keymap (Keymap keymap)
699 Makes @var{keymap} the currently active keymap.
702 @deftypefun Keymap rl_get_keymap_by_name (const char *name)
703 Return the keymap matching @var{name}. @var{name} is one which would
704 be supplied in a @code{set keymap} inputrc line (@pxref{Readline Init File}).
707 @deftypefun {char *} rl_get_keymap_name (Keymap keymap)
708 Return the name matching @var{keymap}. @var{name} is one which would
709 be supplied in a @code{set keymap} inputrc line (@pxref{Readline Init File}).
713 @subsection Binding Keys
715 Key sequences are associate with functions through the keymap.
716 Readline has several internal keymaps: @code{emacs_standard_keymap},
717 @code{emacs_meta_keymap}, @code{emacs_ctlx_keymap},
718 @code{vi_movement_keymap}, and @code{vi_insertion_keymap}.
719 @code{emacs_standard_keymap} is the default, and the examples in
720 this manual assume that.
722 Since @code{readline()} installs a set of default key bindings the first
723 time it is called, there is always the danger that a custom binding
724 installed before the first call to @code{readline()} will be overridden.
725 An alternate mechanism is to install custom key bindings in an
726 initialization function assigned to the @code{rl_startup_hook} variable
727 (@pxref{Readline Variables}).
729 These functions manage key bindings.
731 @deftypefun int rl_bind_key (int key, rl_command_func_t *function)
732 Binds @var{key} to @var{function} in the currently active keymap.
733 Returns non-zero in the case of an invalid @var{key}.
736 @deftypefun int rl_bind_key_in_map (int key, rl_command_func_t *function, Keymap map)
737 Bind @var{key} to @var{function} in @var{map}.
738 Returns non-zero in the case of an invalid @var{key}.
741 @deftypefun int rl_bind_key_if_unbound (int key, rl_command_func_t *function)
742 Binds @var{key} to @var{function} if it is not already bound in the
743 currently active keymap.
744 Returns non-zero in the case of an invalid @var{key} or if @var{key} is
748 @deftypefun int rl_bind_key_if_unbound_in_map (int key, rl_command_func_t *function, Keymap map)
749 Binds @var{key} to @var{function} if it is not already bound in @var{map}.
750 Returns non-zero in the case of an invalid @var{key} or if @var{key} is
754 @deftypefun int rl_unbind_key (int key)
755 Bind @var{key} to the null function in the currently active keymap.
756 Returns non-zero in case of error.
759 @deftypefun int rl_unbind_key_in_map (int key, Keymap map)
760 Bind @var{key} to the null function in @var{map}.
761 Returns non-zero in case of error.
764 @deftypefun int rl_unbind_function_in_map (rl_command_func_t *function, Keymap map)
765 Unbind all keys that execute @var{function} in @var{map}.
768 @deftypefun int rl_unbind_command_in_map (const char *command, Keymap map)
769 Unbind all keys that are bound to @var{command} in @var{map}.
772 @deftypefun int rl_bind_keyseq (const char *keyseq, rl_command_func_t *function)
773 Bind the key sequence represented by the string @var{keyseq} to the function
774 @var{function}, beginning in the current keymap.
775 This makes new keymaps as necessary.
776 The return value is non-zero if @var{keyseq} is invalid.
779 @deftypefun int rl_bind_keyseq_in_map (const char *keyseq, rl_command_func_t *function, Keymap map)
780 Bind the key sequence represented by the string @var{keyseq} to the function
781 @var{function}. This makes new keymaps as necessary.
782 Initial bindings are performed in @var{map}.
783 The return value is non-zero if @var{keyseq} is invalid.
786 @deftypefun int rl_set_key (const char *keyseq, rl_command_func_t *function, Keymap map)
787 Equivalent to @code{rl_bind_keyseq_in_map}.
790 @deftypefun int rl_bind_keyseq_if_unbound (const char *keyseq, rl_command_func_t *function)
791 Binds @var{keyseq} to @var{function} if it is not already bound in the
792 currently active keymap.
793 Returns non-zero in the case of an invalid @var{keyseq} or if @var{keyseq} is
797 @deftypefun int rl_bind_keyseq_if_unbound_in_map (const char *keyseq, rl_command_func_t *function, Keymap map)
798 Binds @var{keyseq} to @var{function} if it is not already bound in @var{map}.
799 Returns non-zero in the case of an invalid @var{keyseq} or if @var{keyseq} is
803 @deftypefun int rl_generic_bind (int type, const char *keyseq, char *data, Keymap map)
804 Bind the key sequence represented by the string @var{keyseq} to the arbitrary
805 pointer @var{data}. @var{type} says what kind of data is pointed to by
806 @var{data}; this can be a function (@code{ISFUNC}), a macro
807 (@code{ISMACR}), or a keymap (@code{ISKMAP}). This makes new keymaps as
808 necessary. The initial keymap in which to do bindings is @var{map}.
811 @deftypefun int rl_parse_and_bind (char *line)
812 Parse @var{line} as if it had been read from the @code{inputrc} file and
813 perform any key bindings and variable assignments found
814 (@pxref{Readline Init File}).
817 @deftypefun int rl_read_init_file (const char *filename)
818 Read keybindings and variable assignments from @var{filename}
819 (@pxref{Readline Init File}).
822 @node Associating Function Names and Bindings
823 @subsection Associating Function Names and Bindings
825 These functions allow you to find out what keys invoke named functions
826 and the functions invoked by a particular key sequence. You may also
827 associate a new function name with an arbitrary function.
829 @deftypefun {rl_command_func_t *} rl_named_function (const char *name)
830 Return the function with name @var{name}.
833 @deftypefun {rl_command_func_t *} rl_function_of_keyseq (const char *keyseq, Keymap map, int *type)
834 Return the function invoked by @var{keyseq} in keymap @var{map}.
835 If @var{map} is @code{NULL}, the current keymap is used. If @var{type} is
836 not @code{NULL}, the type of the object is returned in the @code{int} variable
837 it points to (one of @code{ISFUNC}, @code{ISKMAP}, or @code{ISMACR}).
840 @deftypefun {char **} rl_invoking_keyseqs (rl_command_func_t *function)
841 Return an array of strings representing the key sequences used to
842 invoke @var{function} in the current keymap.
845 @deftypefun {char **} rl_invoking_keyseqs_in_map (rl_command_func_t *function, Keymap map)
846 Return an array of strings representing the key sequences used to
847 invoke @var{function} in the keymap @var{map}.
850 @deftypefun void rl_function_dumper (int readable)
851 Print the readline function names and the key sequences currently
852 bound to them to @code{rl_outstream}. If @var{readable} is non-zero,
853 the list is formatted in such a way that it can be made part of an
854 @code{inputrc} file and re-read.
857 @deftypefun void rl_list_funmap_names (void)
858 Print the names of all bindable Readline functions to @code{rl_outstream}.
861 @deftypefun {const char **} rl_funmap_names (void)
862 Return a NULL terminated array of known function names. The array is
863 sorted. The array itself is allocated, but not the strings inside. You
864 should free the array, but not the pointers, using @code{free} or
865 @code{rl_free} when you are done.
868 @deftypefun int rl_add_funmap_entry (const char *name, rl_command_func_t *function)
869 Add @var{name} to the list of bindable Readline command names, and make
870 @var{function} the function to be called when @var{name} is invoked.
873 @node Allowing Undoing
874 @subsection Allowing Undoing
876 Supporting the undo command is a painless thing, and makes your
877 functions much more useful. It is certainly easy to try
878 something if you know you can undo it.
880 If your function simply inserts text once, or deletes text once, and
881 uses @code{rl_insert_text()} or @code{rl_delete_text()} to do it, then
882 undoing is already done for you automatically.
884 If you do multiple insertions or multiple deletions, or any combination
885 of these operations, you should group them together into one operation.
886 This is done with @code{rl_begin_undo_group()} and
887 @code{rl_end_undo_group()}.
889 The types of events that can be undone are:
892 enum undo_code @{ UNDO_DELETE, UNDO_INSERT, UNDO_BEGIN, UNDO_END @};
895 Notice that @code{UNDO_DELETE} means to insert some text, and
896 @code{UNDO_INSERT} means to delete some text. That is, the undo code
897 tells what to undo, not how to undo it. @code{UNDO_BEGIN} and
898 @code{UNDO_END} are tags added by @code{rl_begin_undo_group()} and
899 @code{rl_end_undo_group()}.
901 @deftypefun int rl_begin_undo_group (void)
902 Begins saving undo information in a group construct. The undo
903 information usually comes from calls to @code{rl_insert_text()} and
904 @code{rl_delete_text()}, but could be the result of calls to
905 @code{rl_add_undo()}.
908 @deftypefun int rl_end_undo_group (void)
909 Closes the current undo group started with @code{rl_begin_undo_group
910 ()}. There should be one call to @code{rl_end_undo_group()}
911 for each call to @code{rl_begin_undo_group()}.
914 @deftypefun void rl_add_undo (enum undo_code what, int start, int end, char *text)
915 Remember how to undo an event (according to @var{what}). The affected
916 text runs from @var{start} to @var{end}, and encompasses @var{text}.
919 @deftypefun void rl_free_undo_list (void)
920 Free the existing undo list.
923 @deftypefun int rl_do_undo (void)
924 Undo the first thing on the undo list. Returns @code{0} if there was
925 nothing to undo, non-zero if something was undone.
928 Finally, if you neither insert nor delete text, but directly modify the
929 existing text (e.g., change its case), call @code{rl_modifying()}
930 once, just before you modify the text. You must supply the indices of
931 the text range that you are going to modify.
933 @deftypefun int rl_modifying (int start, int end)
934 Tell Readline to save the text between @var{start} and @var{end} as a
935 single undo unit. It is assumed that you will subsequently modify
940 @subsection Redisplay
942 @deftypefun void rl_redisplay (void)
943 Change what's displayed on the screen to reflect the current contents
944 of @code{rl_line_buffer}.
947 @deftypefun int rl_forced_update_display (void)
948 Force the line to be updated and redisplayed, whether or not
949 Readline thinks the screen display is correct.
952 @deftypefun int rl_on_new_line (void)
953 Tell the update functions that we have moved onto a new (empty) line,
954 usually after outputting a newline.
957 @deftypefun int rl_on_new_line_with_prompt (void)
958 Tell the update functions that we have moved onto a new line, with
959 @var{rl_prompt} already displayed.
960 This could be used by applications that want to output the prompt string
961 themselves, but still need Readline to know the prompt string length for
963 It should be used after setting @var{rl_already_prompted}.
966 @deftypefun int rl_reset_line_state (void)
967 Reset the display state to a clean state and redisplay the current line
968 starting on a new line.
971 @deftypefun int rl_crlf (void)
972 Move the cursor to the start of the next screen line.
975 @deftypefun int rl_show_char (int c)
976 Display character @var{c} on @code{rl_outstream}.
977 If Readline has not been set to display meta characters directly, this
978 will convert meta characters to a meta-prefixed key sequence.
979 This is intended for use by applications which wish to do their own
983 @deftypefun int rl_message (const char *, @dots{})
984 The arguments are a format string as would be supplied to @code{printf},
985 possibly containing conversion specifications such as @samp{%d}, and
986 any additional arguments necessary to satisfy the conversion specifications.
987 The resulting string is displayed in the @dfn{echo area}. The echo area
988 is also used to display numeric arguments and search strings.
989 You should call @code{rl_save_prompt} to save the prompt information
990 before calling this function.
993 @deftypefun int rl_clear_message (void)
994 Clear the message in the echo area. If the prompt was saved with a call to
995 @code{rl_save_prompt} before the last call to @code{rl_message},
996 call @code{rl_restore_prompt} before calling this function.
999 @deftypefun void rl_save_prompt (void)
1000 Save the local Readline prompt display state in preparation for
1001 displaying a new message in the message area with @code{rl_message()}.
1004 @deftypefun void rl_restore_prompt (void)
1005 Restore the local Readline prompt display state saved by the most
1006 recent call to @code{rl_save_prompt}.
1007 if @code{rl_save_prompt} was called to save the prompt before a call
1008 to @code{rl_message}, this function should be called before the
1009 corresponding call to @code{rl_clear_message}.
1012 @deftypefun int rl_expand_prompt (char *prompt)
1013 Expand any special character sequences in @var{prompt} and set up the
1014 local Readline prompt redisplay variables.
1015 This function is called by @code{readline()}. It may also be called to
1016 expand the primary prompt if the @code{rl_on_new_line_with_prompt()}
1017 function or @code{rl_already_prompted} variable is used.
1018 It returns the number of visible characters on the last line of the
1019 (possibly multi-line) prompt.
1020 Applications may indicate that the prompt contains characters that take
1021 up no physical screen space when displayed by bracketing a sequence of
1022 such characters with the special markers @code{RL_PROMPT_START_IGNORE}
1023 and @code{RL_PROMPT_END_IGNORE} (declared in @file{readline.h}. This may
1024 be used to embed terminal-specific escape sequences in prompts.
1027 @deftypefun int rl_set_prompt (const char *prompt)
1028 Make Readline use @var{prompt} for subsequent redisplay. This calls
1029 @code{rl_expand_prompt()} to expand the prompt and sets @code{rl_prompt}
1033 @node Modifying Text
1034 @subsection Modifying Text
1036 @deftypefun int rl_insert_text (const char *text)
1037 Insert @var{text} into the line at the current cursor position.
1038 Returns the number of characters inserted.
1041 @deftypefun int rl_delete_text (int start, int end)
1042 Delete the text between @var{start} and @var{end} in the current line.
1043 Returns the number of characters deleted.
1046 @deftypefun {char *} rl_copy_text (int start, int end)
1047 Return a copy of the text between @var{start} and @var{end} in
1051 @deftypefun int rl_kill_text (int start, int end)
1052 Copy the text between @var{start} and @var{end} in the current line
1053 to the kill ring, appending or prepending to the last kill if the
1054 last command was a kill command. The text is deleted.
1055 If @var{start} is less than @var{end},
1056 the text is appended, otherwise prepended. If the last command was
1057 not a kill, a new kill ring slot is used.
1060 @deftypefun int rl_push_macro_input (char *macro)
1061 Cause @var{macro} to be inserted into the line, as if it had been invoked
1062 by a key bound to a macro. Not especially useful; use
1063 @code{rl_insert_text()} instead.
1066 @node Character Input
1067 @subsection Character Input
1069 @deftypefun int rl_read_key (void)
1070 Return the next character available from Readline's current input stream.
1071 This handles input inserted into
1072 the input stream via @var{rl_pending_input} (@pxref{Readline Variables})
1073 and @code{rl_stuff_char()}, macros, and characters read from the keyboard.
1074 While waiting for input, this function will call any function assigned to
1075 the @code{rl_event_hook} variable.
1078 @deftypefun int rl_getc (FILE *stream)
1079 Return the next character available from @var{stream}, which is assumed to
1083 @deftypefun int rl_stuff_char (int c)
1084 Insert @var{c} into the Readline input stream. It will be "read"
1085 before Readline attempts to read characters from the terminal with
1086 @code{rl_read_key()}. Up to 512 characters may be pushed back.
1087 @code{rl_stuff_char} returns 1 if the character was successfully inserted;
1091 @deftypefun int rl_execute_next (int c)
1092 Make @var{c} be the next command to be executed when @code{rl_read_key()}
1093 is called. This sets @var{rl_pending_input}.
1096 @deftypefun int rl_clear_pending_input (void)
1097 Unset @var{rl_pending_input}, effectively negating the effect of any
1098 previous call to @code{rl_execute_next()}. This works only if the
1099 pending input has not already been read with @code{rl_read_key()}.
1102 @deftypefun int rl_set_keyboard_input_timeout (int u)
1103 While waiting for keyboard input in @code{rl_read_key()}, Readline will
1104 wait for @var{u} microseconds for input before calling any function
1105 assigned to @code{rl_event_hook}. @var{u} must be greater than or equal
1106 to zero (a zero-length timeout is equivalent to a poll).
1107 The default waiting period is one-tenth of a second.
1108 Returns the old timeout value.
1111 @node Terminal Management
1112 @subsection Terminal Management
1114 @deftypefun void rl_prep_terminal (int meta_flag)
1115 Modify the terminal settings for Readline's use, so @code{readline()}
1116 can read a single character at a time from the keyboard.
1117 The @var{meta_flag} argument should be non-zero if Readline should
1118 read eight-bit input.
1121 @deftypefun void rl_deprep_terminal (void)
1122 Undo the effects of @code{rl_prep_terminal()}, leaving the terminal in
1123 the state in which it was before the most recent call to
1124 @code{rl_prep_terminal()}.
1127 @deftypefun void rl_tty_set_default_bindings (Keymap kmap)
1128 Read the operating system's terminal editing characters (as would be
1129 displayed by @code{stty}) to their Readline equivalents.
1130 The bindings are performed in @var{kmap}.
1133 @deftypefun void rl_tty_unset_default_bindings (Keymap kmap)
1134 Reset the bindings manipulated by @code{rl_tty_set_default_bindings} so
1135 that the terminal editing characters are bound to @code{rl_insert}.
1136 The bindings are performed in @var{kmap}.
1139 @deftypefun int rl_reset_terminal (const char *terminal_name)
1140 Reinitialize Readline's idea of the terminal settings using
1141 @var{terminal_name} as the terminal type (e.g., @code{vt100}).
1142 If @var{terminal_name} is @code{NULL}, the value of the @code{TERM}
1143 environment variable is used.
1146 @node Utility Functions
1147 @subsection Utility Functions
1149 @deftypefun int rl_save_state (struct readline_state *sp)
1150 Save a snapshot of Readline's internal state to @var{sp}.
1151 The contents of the @var{readline_state} structure are documented
1152 in @file{readline.h}.
1153 The caller is responsible for allocating the structure.
1156 @deftypefun int rl_restore_state (struct readline_state *sp)
1157 Restore Readline's internal state to that stored in @var{sp}, which must
1158 have been saved by a call to @code{rl_save_state}.
1159 The contents of the @var{readline_state} structure are documented
1160 in @file{readline.h}.
1161 The caller is responsible for freeing the structure.
1164 @deftypefun void rl_free (void *mem)
1165 Deallocate the memory pointed to by @var{mem}. @var{mem} must have been
1166 allocated by @code{malloc}.
1169 @deftypefun void rl_replace_line (const char *text, int clear_undo)
1170 Replace the contents of @code{rl_line_buffer} with @var{text}.
1171 The point and mark are preserved, if possible.
1172 If @var{clear_undo} is non-zero, the undo list associated with the
1173 current line is cleared.
1176 @deftypefun void rl_extend_line_buffer (int len)
1177 Ensure that @code{rl_line_buffer} has enough space to hold @var{len}
1178 characters, possibly reallocating it if necessary.
1181 @deftypefun int rl_initialize (void)
1182 Initialize or re-initialize Readline's internal state.
1183 It's not strictly necessary to call this; @code{readline()} calls it before
1187 @deftypefun int rl_ding (void)
1188 Ring the terminal bell, obeying the setting of @code{bell-style}.
1191 @deftypefun int rl_alphabetic (int c)
1192 Return 1 if @var{c} is an alphabetic character.
1195 @deftypefun void rl_display_match_list (char **matches, int len, int max)
1196 A convenience function for displaying a list of strings in
1197 columnar format on Readline's output stream. @code{matches} is the list
1198 of strings, in argv format, such as a list of completion matches.
1199 @code{len} is the number of strings in @code{matches}, and @code{max}
1200 is the length of the longest string in @code{matches}. This function uses
1201 the setting of @code{print-completions-horizontally} to select how the
1202 matches are displayed (@pxref{Readline Init File Syntax}).
1203 When displaying completions, this function sets the number of columns used
1204 for display to the value of @code{completion-display-width}, the value of
1205 the environment variable @env{COLUMNS}, or the screen width, in that order.
1208 The following are implemented as macros, defined in @code{chardefs.h}.
1209 Applications should refrain from using them.
1211 @deftypefun int _rl_uppercase_p (int c)
1212 Return 1 if @var{c} is an uppercase alphabetic character.
1215 @deftypefun int _rl_lowercase_p (int c)
1216 Return 1 if @var{c} is a lowercase alphabetic character.
1219 @deftypefun int _rl_digit_p (int c)
1220 Return 1 if @var{c} is a numeric character.
1223 @deftypefun int _rl_to_upper (int c)
1224 If @var{c} is a lowercase alphabetic character, return the corresponding
1225 uppercase character.
1228 @deftypefun int _rl_to_lower (int c)
1229 If @var{c} is an uppercase alphabetic character, return the corresponding
1230 lowercase character.
1233 @deftypefun int _rl_digit_value (int c)
1234 If @var{c} is a number, return the value it represents.
1237 @node Miscellaneous Functions
1238 @subsection Miscellaneous Functions
1240 @deftypefun int rl_macro_bind (const char *keyseq, const char *macro, Keymap map)
1241 Bind the key sequence @var{keyseq} to invoke the macro @var{macro}.
1242 The binding is performed in @var{map}. When @var{keyseq} is invoked, the
1243 @var{macro} will be inserted into the line. This function is deprecated;
1244 use @code{rl_generic_bind()} instead.
1247 @deftypefun void rl_macro_dumper (int readable)
1248 Print the key sequences bound to macros and their values, using
1249 the current keymap, to @code{rl_outstream}.
1250 If @var{readable} is non-zero, the list is formatted in such a way
1251 that it can be made part of an @code{inputrc} file and re-read.
1254 @deftypefun int rl_variable_bind (const char *variable, const char *value)
1255 Make the Readline variable @var{variable} have @var{value}.
1256 This behaves as if the readline command
1257 @samp{set @var{variable} @var{value}} had been executed in an @code{inputrc}
1258 file (@pxref{Readline Init File Syntax}).
1261 @deftypefun {char *} rl_variable_value (const char *variable)
1262 Return a string representing the value of the Readline variable @var{variable}.
1263 For boolean variables, this string is either @samp{on} or @samp{off}.
1266 @deftypefun void rl_variable_dumper (int readable)
1267 Print the readline variable names and their current values
1268 to @code{rl_outstream}.
1269 If @var{readable} is non-zero, the list is formatted in such a way
1270 that it can be made part of an @code{inputrc} file and re-read.
1273 @deftypefun int rl_set_paren_blink_timeout (int u)
1274 Set the time interval (in microseconds) that Readline waits when showing
1275 a balancing character when @code{blink-matching-paren} has been enabled.
1278 @deftypefun {char *} rl_get_termcap (const char *cap)
1279 Retrieve the string value of the termcap capability @var{cap}.
1280 Readline fetches the termcap entry for the current terminal name and
1281 uses those capabilities to move around the screen line and perform other
1282 terminal-specific operations, like erasing a line. Readline does not
1283 use all of a terminal's capabilities, and this function will return
1284 values for only those capabilities Readline uses.
1287 @deftypefun {void} rl_clear_history (void)
1288 Clear the history list by deleting all of the entries, in the same manner
1289 as the History library's @code{clear_history()} function.
1290 This differs from @code{clear_history} because it frees private data
1291 Readline saves in the history list.
1294 @node Alternate Interface
1295 @subsection Alternate Interface
1297 An alternate interface is available to plain @code{readline()}. Some
1298 applications need to interleave keyboard I/O with file, device, or
1299 window system I/O, typically by using a main loop to @code{select()}
1300 on various file descriptors. To accommodate this need, readline can
1301 also be invoked as a `callback' function from an event loop. There
1302 are functions available to make this easy.
1304 @deftypefun void rl_callback_handler_install (const char *prompt, rl_vcpfunc_t *lhandler)
1305 Set up the terminal for readline I/O and display the initial
1306 expanded value of @var{prompt}. Save the value of @var{lhandler} to
1307 use as a handler function to call when a complete line of input has been
1309 The handler function receives the text of the line as an argument.
1312 @deftypefun void rl_callback_read_char (void)
1313 Whenever an application determines that keyboard input is available, it
1314 should call @code{rl_callback_read_char()}, which will read the next
1315 character from the current input source.
1316 If that character completes the line, @code{rl_callback_read_char} will
1317 invoke the @var{lhandler} function installed by
1318 @code{rl_callback_handler_install} to process the line.
1319 Before calling the @var{lhandler} function, the terminal settings are
1320 reset to the values they had before calling
1321 @code{rl_callback_handler_install}.
1322 If the @var{lhandler} function returns,
1323 and the line handler remains installed,
1324 the terminal settings are modified for Readline's use again.
1325 @code{EOF} is indicated by calling @var{lhandler} with a
1329 @deftypefun void rl_callback_handler_remove (void)
1330 Restore the terminal to its initial state and remove the line handler.
1331 This may be called from within a callback as well as independently.
1332 If the @var{lhandler} installed by @code{rl_callback_handler_install}
1333 does not exit the program, either this function or the function referred
1334 to by the value of @code{rl_deprep_term_function} should be called before
1335 the program exits to reset the terminal settings.
1338 @node A Readline Example
1339 @subsection A Readline Example
1341 Here is a function which changes lowercase characters to their uppercase
1342 equivalents, and uppercase characters to lowercase. If
1343 this function was bound to @samp{M-c}, then typing @samp{M-c} would
1344 change the case of the character under point. Typing @samp{M-1 0 M-c}
1345 would change the case of the following 10 characters, leaving the cursor on
1346 the last character changed.
1349 /* Invert the case of the COUNT following characters. */
1351 invert_case_line (count, key)
1354 register int start, end, i;
1358 if (rl_point >= rl_end)
1369 /* Find the end of the range to modify. */
1370 end = start + (count * direction);
1372 /* Force it to be within range. */
1388 /* Tell readline that we are modifying the line,
1389 so it will save the undo information. */
1390 rl_modifying (start, end);
1392 for (i = start; i != end; i++)
1394 if (_rl_uppercase_p (rl_line_buffer[i]))
1395 rl_line_buffer[i] = _rl_to_lower (rl_line_buffer[i]);
1396 else if (_rl_lowercase_p (rl_line_buffer[i]))
1397 rl_line_buffer[i] = _rl_to_upper (rl_line_buffer[i]);
1399 /* Move point to on top of the last character changed. */
1400 rl_point = (direction == 1) ? end - 1 : start;
1405 @node Alternate Interface Example
1406 @subsection Alternate Interface Example
1408 Here is a complete program that illustrates Readline's alternate interface.
1409 It reads lines from the terminal and displays them, providing the
1410 standard history and TAB completion functions.
1411 It understands the EOF character or "exit" to exit the program.
1414 /* Standard include files. stdio.h is required. */
1418 /* Used for select(2) */
1419 #include <sys/types.h>
1420 #include <sys/select.h>
1424 /* Standard readline include files. */
1425 #include <readline/readline.h>
1426 #include <readline/history.h>
1428 static void cb_linehandler (char *);
1431 const char *prompt = "rltest$ ";
1433 /* Callback function called for each line when accept-line executed, EOF
1434 seen, or EOF character read. This sets a flag and returns; it could
1435 also call exit(3). */
1437 cb_linehandler (char *line)
1439 /* Can use ^D (stty eof) or `exit' to exit. */
1440 if (line == NULL || strcmp (line, "exit") == 0)
1445 /* This function needs to be called to reset the terminal settings,
1446 and calling it from the line handler keeps one extra prompt from
1448 rl_callback_handler_remove ();
1456 printf ("input line: %s\n", line);
1462 main (int c, char **v)
1467 /* Install the line handler. */
1468 rl_callback_handler_install (prompt, cb_linehandler);
1470 /* Enter a simple event loop. This waits until something is available
1471 to read on readline's input stream (defaults to standard input) and
1472 calls the builtin character read callback to read it. It does not
1473 have to modify the user's terminal settings. */
1478 FD_SET (fileno (rl_instream), &fds);
1480 r = select (FD_SETSIZE, &fds, NULL, NULL, NULL);
1483 perror ("rltest: select");
1484 rl_callback_handler_remove ();
1488 if (FD_ISSET (fileno (rl_instream), &fds))
1489 rl_callback_read_char ();
1492 printf ("rltest: Event loop has exited\n");
1497 @node Readline Signal Handling
1498 @section Readline Signal Handling
1500 Signals are asynchronous events sent to a process by the Unix kernel,
1501 sometimes on behalf of another process. They are intended to indicate
1502 exceptional events, like a user pressing the interrupt key on his terminal,
1503 or a network connection being broken. There is a class of signals that can
1504 be sent to the process currently reading input from the keyboard. Since
1505 Readline changes the terminal attributes when it is called, it needs to
1506 perform special processing when such a signal is received in order to
1507 restore the terminal to a sane state, or provide application writers with
1508 functions to do so manually.
1510 Readline contains an internal signal handler that is installed for a
1511 number of signals (@code{SIGINT}, @code{SIGQUIT}, @code{SIGTERM},
1513 @code{SIGALRM}, @code{SIGTSTP}, @code{SIGTTIN}, and @code{SIGTTOU}).
1514 When one of these signals is received, the signal handler
1515 will reset the terminal attributes to those that were in effect before
1516 @code{readline()} was called, reset the signal handling to what it was
1517 before @code{readline()} was called, and resend the signal to the calling
1519 If and when the calling application's signal handler returns, Readline
1520 will reinitialize the terminal and continue to accept input.
1521 When a @code{SIGINT} is received, the Readline signal handler performs
1522 some additional work, which will cause any partially-entered line to be
1523 aborted (see the description of @code{rl_free_line_state()} below).
1525 There is an additional Readline signal handler, for @code{SIGWINCH}, which
1526 the kernel sends to a process whenever the terminal's size changes (for
1527 example, if a user resizes an @code{xterm}). The Readline @code{SIGWINCH}
1528 handler updates Readline's internal screen size information, and then calls
1529 any @code{SIGWINCH} signal handler the calling application has installed.
1530 Readline calls the application's @code{SIGWINCH} signal handler without
1531 resetting the terminal to its original state. If the application's signal
1532 handler does more than update its idea of the terminal size and return (for
1533 example, a @code{longjmp} back to a main processing loop), it @emph{must}
1534 call @code{rl_cleanup_after_signal()} (described below), to restore the
1537 Readline provides two variables that allow application writers to
1538 control whether or not it will catch certain signals and act on them
1539 when they are received. It is important that applications change the
1540 values of these variables only when calling @code{readline()}, not in
1541 a signal handler, so Readline's internal signal state is not corrupted.
1543 @deftypevar int rl_catch_signals
1544 If this variable is non-zero, Readline will install signal handlers for
1545 @code{SIGINT}, @code{SIGQUIT}, @code{SIGTERM}, @code{SIGHUP}, @code{SIGALRM},
1546 @code{SIGTSTP}, @code{SIGTTIN}, and @code{SIGTTOU}.
1548 The default value of @code{rl_catch_signals} is 1.
1551 @deftypevar int rl_catch_sigwinch
1552 If this variable is set to a non-zero value,
1553 Readline will install a signal handler for @code{SIGWINCH}.
1555 The default value of @code{rl_catch_sigwinch} is 1.
1558 @deftypevar int rl_change_environment
1559 If this variable is set to a non-zero value,
1560 and Readline is handling @code{SIGWINCH}, Readline will modify the
1561 @var{LINES} and @var{COLUMNS} environment variables upon receipt of a
1564 The default value of @code{rl_change_environment} is 1.
1567 If an application does not wish to have Readline catch any signals, or
1568 to handle signals other than those Readline catches (@code{SIGHUP},
1570 Readline provides convenience functions to do the necessary terminal
1571 and internal state cleanup upon receipt of a signal.
1573 @deftypefun void rl_cleanup_after_signal (void)
1574 This function will reset the state of the terminal to what it was before
1575 @code{readline()} was called, and remove the Readline signal handlers for
1576 all signals, depending on the values of @code{rl_catch_signals} and
1577 @code{rl_catch_sigwinch}.
1580 @deftypefun void rl_free_line_state (void)
1581 This will free any partial state associated with the current input line
1582 (undo information, any partial history entry, any partially-entered
1583 keyboard macro, and any partially-entered numeric argument). This
1584 should be called before @code{rl_cleanup_after_signal()}. The
1585 Readline signal handler for @code{SIGINT} calls this to abort the
1589 @deftypefun void rl_reset_after_signal (void)
1590 This will reinitialize the terminal and reinstall any Readline signal
1591 handlers, depending on the values of @code{rl_catch_signals} and
1592 @code{rl_catch_sigwinch}.
1595 If an application does not wish Readline to catch @code{SIGWINCH}, it may
1596 call @code{rl_resize_terminal()} or @code{rl_set_screen_size()} to force
1597 Readline to update its idea of the terminal size when a @code{SIGWINCH}
1600 @deftypefun void rl_echo_signal_char (int sig)
1601 If an application wishes to install its own signal handlers, but still
1602 have readline display characters that generate signals, calling this
1603 function with @var{sig} set to @code{SIGINT}, @code{SIGQUIT}, or
1604 @code{SIGTSTP} will display the character generating that signal.
1607 @deftypefun void rl_resize_terminal (void)
1608 Update Readline's internal screen size by reading values from the kernel.
1611 @deftypefun void rl_set_screen_size (int rows, int cols)
1612 Set Readline's idea of the terminal size to @var{rows} rows and
1613 @var{cols} columns. If either @var{rows} or @var{columns} is less than
1614 or equal to 0, Readline's idea of that terminal dimension is unchanged.
1617 If an application does not want to install a @code{SIGWINCH} handler, but
1618 is still interested in the screen dimensions, Readline's idea of the screen
1619 size may be queried.
1621 @deftypefun void rl_get_screen_size (int *rows, int *cols)
1622 Return Readline's idea of the terminal's size in the
1623 variables pointed to by the arguments.
1626 @deftypefun void rl_reset_screen_size (void)
1627 Cause Readline to reobtain the screen size and recalculate its dimensions.
1630 The following functions install and remove Readline's signal handlers.
1632 @deftypefun int rl_set_signals (void)
1633 Install Readline's signal handler for @code{SIGINT}, @code{SIGQUIT},
1634 @code{SIGTERM}, @code{SIGHUP}, @code{SIGALRM}, @code{SIGTSTP}, @code{SIGTTIN},
1635 @code{SIGTTOU}, and @code{SIGWINCH}, depending on the values of
1636 @code{rl_catch_signals} and @code{rl_catch_sigwinch}.
1639 @deftypefun int rl_clear_signals (void)
1640 Remove all of the Readline signal handlers installed by
1641 @code{rl_set_signals()}.
1644 @node Custom Completers
1645 @section Custom Completers
1646 @cindex application-specific completion functions
1648 Typically, a program that reads commands from the user has a way of
1649 disambiguating commands and data. If your program is one of these, then
1650 it can provide completion for commands, data, or both.
1651 The following sections describe how your program and Readline
1652 cooperate to provide this service.
1655 * How Completing Works:: The logic used to do completion.
1656 * Completion Functions:: Functions provided by Readline.
1657 * Completion Variables:: Variables which control completion.
1658 * A Short Completion Example:: An example of writing completer subroutines.
1661 @node How Completing Works
1662 @subsection How Completing Works
1664 In order to complete some text, the full list of possible completions
1665 must be available. That is, it is not possible to accurately
1666 expand a partial word without knowing all of the possible words
1667 which make sense in that context. The Readline library provides
1668 the user interface to completion, and two of the most common
1669 completion functions: filename and username. For completing other types
1670 of text, you must write your own completion function. This section
1671 describes exactly what such functions must do, and provides an example.
1673 There are three major functions used to perform completion:
1677 The user-interface function @code{rl_complete()}. This function is
1678 called with the same arguments as other bindable Readline functions:
1679 @var{count} and @var{invoking_key}.
1680 It isolates the word to be completed and calls
1681 @code{rl_completion_matches()} to generate a list of possible completions.
1682 It then either lists the possible completions, inserts the possible
1683 completions, or actually performs the
1684 completion, depending on which behavior is desired.
1687 The internal function @code{rl_completion_matches()} uses an
1688 application-supplied @dfn{generator} function to generate the list of
1689 possible matches, and then returns the array of these matches.
1690 The caller should place the address of its generator function in
1691 @code{rl_completion_entry_function}.
1694 The generator function is called repeatedly from
1695 @code{rl_completion_matches()}, returning a string each time. The
1696 arguments to the generator function are @var{text} and @var{state}.
1697 @var{text} is the partial word to be completed. @var{state} is zero the
1698 first time the function is called, allowing the generator to perform
1699 any necessary initialization, and a positive non-zero integer for
1700 each subsequent call. The generator function returns
1701 @code{(char *)NULL} to inform @code{rl_completion_matches()} that there are
1702 no more possibilities left. Usually the generator function computes the
1703 list of possible completions when @var{state} is zero, and returns them
1704 one at a time on subsequent calls. Each string the generator function
1705 returns as a match must be allocated with @code{malloc()}; Readline
1706 frees the strings when it has finished with them.
1707 Such a generator function is referred to as an
1708 @dfn{application-specific completion function}.
1712 @deftypefun int rl_complete (int ignore, int invoking_key)
1713 Complete the word at or before point. You have supplied the function
1714 that does the initial simple matching selection algorithm (see
1715 @code{rl_completion_matches()}). The default is to do filename completion.
1718 @deftypevar {rl_compentry_func_t *} rl_completion_entry_function
1719 This is a pointer to the generator function for
1720 @code{rl_completion_matches()}.
1721 If the value of @code{rl_completion_entry_function} is
1722 @code{NULL} then the default filename generator
1723 function, @code{rl_filename_completion_function()}, is used.
1724 An @dfn{application-specific completion function} is a function whose
1725 address is assigned to @code{rl_completion_entry_function} and whose
1726 return values are used to generate possible completions.
1729 @node Completion Functions
1730 @subsection Completion Functions
1732 Here is the complete list of callable completion functions present in
1735 @deftypefun int rl_complete_internal (int what_to_do)
1736 Complete the word at or before point. @var{what_to_do} says what to do
1737 with the completion. A value of @samp{?} means list the possible
1738 completions. @samp{TAB} means do standard completion. @samp{*} means
1739 insert all of the possible completions. @samp{!} means to display
1740 all of the possible completions, if there is more than one, as well as
1741 performing partial completion. @samp{@@} is similar to @samp{!}, but
1742 possible completions are not listed if the possible completions share
1746 @deftypefun int rl_complete (int ignore, int invoking_key)
1747 Complete the word at or before point. You have supplied the function
1748 that does the initial simple matching selection algorithm (see
1749 @code{rl_completion_matches()} and @code{rl_completion_entry_function}).
1750 The default is to do filename
1751 completion. This calls @code{rl_complete_internal()} with an
1752 argument depending on @var{invoking_key}.
1755 @deftypefun int rl_possible_completions (int count, int invoking_key)
1756 List the possible completions. See description of @code{rl_complete
1757 ()}. This calls @code{rl_complete_internal()} with an argument of
1761 @deftypefun int rl_insert_completions (int count, int invoking_key)
1762 Insert the list of possible completions into the line, deleting the
1763 partially-completed word. See description of @code{rl_complete()}.
1764 This calls @code{rl_complete_internal()} with an argument of @samp{*}.
1767 @deftypefun int rl_completion_mode (rl_command_func_t *cfunc)
1768 Returns the appropriate value to pass to @code{rl_complete_internal()}
1769 depending on whether @var{cfunc} was called twice in succession and
1770 the values of the @code{show-all-if-ambiguous} and
1771 @code{show-all-if-unmodified} variables.
1772 Application-specific completion functions may use this function to present
1773 the same interface as @code{rl_complete()}.
1776 @deftypefun {char **} rl_completion_matches (const char *text, rl_compentry_func_t *entry_func)
1777 Returns an array of strings which is a list of completions for
1778 @var{text}. If there are no completions, returns @code{NULL}.
1779 The first entry in the returned array is the substitution for @var{text}.
1780 The remaining entries are the possible completions. The array is
1781 terminated with a @code{NULL} pointer.
1783 @var{entry_func} is a function of two args, and returns a
1784 @code{char *}. The first argument is @var{text}. The second is a
1785 state argument; it is zero on the first call, and non-zero on subsequent
1786 calls. @var{entry_func} returns a @code{NULL} pointer to the caller
1787 when there are no more matches.
1790 @deftypefun {char *} rl_filename_completion_function (const char *text, int state)
1791 A generator function for filename completion in the general case.
1792 @var{text} is a partial filename.
1793 The Bash source is a useful reference for writing application-specific
1794 completion functions (the Bash completion functions call this and other
1795 Readline functions).
1798 @deftypefun {char *} rl_username_completion_function (const char *text, int state)
1799 A completion generator for usernames. @var{text} contains a partial
1800 username preceded by a random character (usually @samp{~}). As with all
1801 completion generators, @var{state} is zero on the first call and non-zero
1802 for subsequent calls.
1805 @node Completion Variables
1806 @subsection Completion Variables
1808 @deftypevar {rl_compentry_func_t *} rl_completion_entry_function
1809 A pointer to the generator function for @code{rl_completion_matches()}.
1810 @code{NULL} means to use @code{rl_filename_completion_function()},
1811 the default filename completer.
1814 @deftypevar {rl_completion_func_t *} rl_attempted_completion_function
1815 A pointer to an alternative function to create matches.
1816 The function is called with @var{text}, @var{start}, and @var{end}.
1817 @var{start} and @var{end} are indices in @code{rl_line_buffer} defining
1818 the boundaries of @var{text}, which is a character string.
1819 If this function exists and returns @code{NULL}, or if this variable is
1820 set to @code{NULL}, then @code{rl_complete()} will call the value of
1821 @code{rl_completion_entry_function} to generate matches, otherwise the
1822 array of strings returned will be used.
1823 If this function sets the @code{rl_attempted_completion_over}
1824 variable to a non-zero value, Readline will not perform its default
1825 completion even if this function returns no matches.
1828 @deftypevar {rl_quote_func_t *} rl_filename_quoting_function
1829 A pointer to a function that will quote a filename in an
1830 application-specific fashion. This is called if filename completion is being
1831 attempted and one of the characters in @code{rl_filename_quote_characters}
1832 appears in a completed filename. The function is called with
1833 @var{text}, @var{match_type}, and @var{quote_pointer}. The @var{text}
1834 is the filename to be quoted. The @var{match_type} is either
1835 @code{SINGLE_MATCH}, if there is only one completion match, or
1836 @code{MULT_MATCH}. Some functions use this to decide whether or not to
1837 insert a closing quote character. The @var{quote_pointer} is a pointer
1838 to any opening quote character the user typed. Some functions choose
1839 to reset this character.
1842 @deftypevar {rl_dequote_func_t *} rl_filename_dequoting_function
1843 A pointer to a function that will remove application-specific quoting
1844 characters from a filename before completion is attempted, so those
1845 characters do not interfere with matching the text against names in
1846 the filesystem. It is called with @var{text}, the text of the word
1847 to be dequoted, and @var{quote_char}, which is the quoting character
1848 that delimits the filename (usually @samp{'} or @samp{"}). If
1849 @var{quote_char} is zero, the filename was not in an embedded string.
1852 @deftypevar {rl_linebuf_func_t *} rl_char_is_quoted_p
1853 A pointer to a function to call that determines whether or not a specific
1854 character in the line buffer is quoted, according to whatever quoting
1855 mechanism the program calling Readline uses. The function is called with
1856 two arguments: @var{text}, the text of the line, and @var{index}, the
1857 index of the character in the line. It is used to decide whether a
1858 character found in @code{rl_completer_word_break_characters} should be
1859 used to break words for the completer.
1862 @deftypevar {rl_compignore_func_t *} rl_ignore_some_completions_function
1863 This function, if defined, is called by the completer when real filename
1864 completion is done, after all the matching names have been generated.
1865 It is passed a @code{NULL} terminated array of matches.
1866 The first element (@code{matches[0]}) is the
1867 maximal substring common to all matches. This function can
1868 re-arrange the list of matches as required, but each element deleted
1869 from the array must be freed.
1872 @deftypevar {rl_icppfunc_t *} rl_directory_completion_hook
1873 This function, if defined, is allowed to modify the directory portion
1874 of filenames Readline completes.
1875 It could be used to expand symbolic links or shell variables in pathnames.
1876 It is called with the address of a string (the current directory name) as an
1877 argument, and may modify that string.
1878 If the string is replaced with a new string, the old value should be freed.
1879 Any modified directory name should have a trailing slash.
1880 The modified value will be used as part of the completion, replacing
1881 the directory portion of the pathname the user typed.
1882 At the least, even if no other expansion is performed, this function should
1883 remove any quote characters from the directory name, because its result will
1884 be passed directly to @code{opendir()}.
1886 The directory completion hook returns an integer that should be non-zero if
1887 the function modifies its directory argument.
1888 The function should not modify the directory argument if it returns 0.
1891 @deftypevar {rl_icppfunc_t *} rl_directory_rewrite_hook;
1892 If non-zero, this is the address of a function to call when completing
1893 a directory name. This function takes the address of the directory name
1894 to be modified as an argument. Unlike @code{rl_directory_completion_hook},
1895 it only modifies the directory name used in @code{opendir}, not what is
1896 displayed when the possible completions are printed or inserted. It is
1897 called before rl_directory_completion_hook.
1898 At the least, even if no other expansion is performed, this function should
1899 remove any quote characters from the directory name, because its result will
1900 be passed directly to @code{opendir()}.
1902 The directory rewrite hook returns an integer that should be non-zero if
1903 the function modfies its directory argument.
1904 The function should not modify the directory argument if it returns 0.
1907 @deftypevar {rl_icppfunc_t *} rl_filename_stat_hook
1908 If non-zero, this is the address of a function for the completer to
1909 call before deciding which character to append to a completed name.
1910 This function modifies its filename name argument, and the modified value
1911 is passed to @code{stat()} to determine the file's type and characteristics.
1912 This function does not need to remove quote characters from the filename.
1914 The stat hook returns an integer that should be non-zero if
1915 the function modfies its directory argument.
1916 The function should not modify the directory argument if it returns 0.
1919 @deftypevar {rl_dequote_func_t *} rl_filename_rewrite_hook
1920 If non-zero, this is the address of a function called when reading
1921 directory entries from the filesystem for completion and comparing
1922 them to the partial word to be completed. The function should
1923 perform any necessary application or system-specific conversion on
1924 the filename, such as converting between character sets or converting
1925 from a filesystem format to a character input format.
1926 The function takes two arguments: @var{fname}, the filename to be converted,
1927 and @var{fnlen}, its length in bytes.
1928 It must either return its first argument (if no conversion takes place)
1929 or the converted filename in newly-allocated memory. The converted
1930 form is used to compare against the word to be completed, and, if it
1931 matches, is added to the list of matches. Readline will free the
1935 @deftypevar {rl_compdisp_func_t *} rl_completion_display_matches_hook
1936 If non-zero, then this is the address of a function to call when
1937 completing a word would normally display the list of possible matches.
1938 This function is called in lieu of Readline displaying the list.
1939 It takes three arguments:
1940 (@code{char **}@var{matches}, @code{int} @var{num_matches}, @code{int} @var{max_length})
1941 where @var{matches} is the array of matching strings,
1942 @var{num_matches} is the number of strings in that array, and
1943 @var{max_length} is the length of the longest string in that array.
1944 Readline provides a convenience function, @code{rl_display_match_list},
1945 that takes care of doing the display to Readline's output stream. That
1946 function may be called from this hook.
1949 @deftypevar {const char *} rl_basic_word_break_characters
1950 The basic list of characters that signal a break between words for the
1951 completer routine. The default value of this variable is the characters
1952 which break words for completion in Bash:
1953 @code{" \t\n\"\\'`@@$><=;|&@{("}.
1956 @deftypevar {const char *} rl_basic_quote_characters
1957 A list of quote characters which can cause a word break.
1960 @deftypevar {const char *} rl_completer_word_break_characters
1961 The list of characters that signal a break between words for
1962 @code{rl_complete_internal()}. The default list is the value of
1963 @code{rl_basic_word_break_characters}.
1966 @deftypevar {rl_cpvfunc_t *} rl_completion_word_break_hook
1967 If non-zero, this is the address of a function to call when Readline is
1968 deciding where to separate words for word completion. It should return
1969 a character string like @code{rl_completer_word_break_characters} to be
1970 used to perform the current completion. The function may choose to set
1971 @code{rl_completer_word_break_characters} itself. If the function
1972 returns @code{NULL}, @code{rl_completer_word_break_characters} is used.
1975 @deftypevar {const char *} rl_completer_quote_characters
1976 A list of characters which can be used to quote a substring of the line.
1977 Completion occurs on the entire substring, and within the substring
1978 @code{rl_completer_word_break_characters} are treated as any other character,
1979 unless they also appear within this list.
1982 @deftypevar {const char *} rl_filename_quote_characters
1983 A list of characters that cause a filename to be quoted by the completer
1984 when they appear in a completed filename. The default is the null string.
1987 @deftypevar {const char *} rl_special_prefixes
1988 The list of characters that are word break characters, but should be
1989 left in @var{text} when it is passed to the completion function.
1990 Programs can use this to help determine what kind of completing to do.
1991 For instance, Bash sets this variable to "$@@" so that it can complete
1992 shell variables and hostnames.
1995 @deftypevar int rl_completion_query_items
1996 Up to this many items will be displayed in response to a
1997 possible-completions call. After that, readline asks the user if she is sure
1998 she wants to see them all. The default value is 100. A negative value
1999 indicates that Readline should never ask the user.
2002 @deftypevar {int} rl_completion_append_character
2003 When a single completion alternative matches at the end of the command
2004 line, this character is appended to the inserted completion text. The
2005 default is a space character (@samp{ }). Setting this to the null
2006 character (@samp{\0}) prevents anything being appended automatically.
2007 This can be changed in application-specific completion functions to
2008 provide the ``most sensible word separator character'' according to
2009 an application-specific command line syntax specification.
2012 @deftypevar int rl_completion_suppress_append
2013 If non-zero, @var{rl_completion_append_character} is not appended to
2014 matches at the end of the command line, as described above.
2015 It is set to 0 before any application-specific completion function
2016 is called, and may only be changed within such a function.
2019 @deftypevar int rl_completion_quote_character
2020 When Readline is completing quoted text, as delimited by one of the
2021 characters in @var{rl_completer_quote_characters}, it sets this variable
2022 to the quoting character found.
2023 This is set before any application-specific completion function is called.
2026 @deftypevar int rl_completion_suppress_quote
2027 If non-zero, Readline does not append a matching quote character when
2028 performing completion on a quoted string.
2029 It is set to 0 before any application-specific completion function
2030 is called, and may only be changed within such a function.
2033 @deftypevar int rl_completion_found_quote
2034 When Readline is completing quoted text, it sets this variable
2035 to a non-zero value if the word being completed contains or is delimited
2036 by any quoting characters, including backslashes.
2037 This is set before any application-specific completion function is called.
2040 @deftypevar int rl_completion_mark_symlink_dirs
2041 If non-zero, a slash will be appended to completed filenames that are
2042 symbolic links to directory names, subject to the value of the
2043 user-settable @var{mark-directories} variable.
2044 This variable exists so that application-specific completion functions
2045 can override the user's global preference (set via the
2046 @var{mark-symlinked-directories} Readline variable) if appropriate.
2047 This variable is set to the user's preference before any
2048 application-specific completion function is called, so unless that
2049 function modifies the value, the user's preferences are honored.
2052 @deftypevar int rl_ignore_completion_duplicates
2053 If non-zero, then duplicates in the matches are removed.
2057 @deftypevar int rl_filename_completion_desired
2058 Non-zero means that the results of the matches are to be treated as
2059 filenames. This is @emph{always} zero when completion is attempted,
2060 and can only be changed
2061 within an application-specific completion function. If it is set to a
2062 non-zero value by such a function, directory names have a slash appended
2063 and Readline attempts to quote completed filenames if they contain any
2064 characters in @code{rl_filename_quote_characters} and
2065 @code{rl_filename_quoting_desired} is set to a non-zero value.
2068 @deftypevar int rl_filename_quoting_desired
2069 Non-zero means that the results of the matches are to be quoted using
2070 double quotes (or an application-specific quoting mechanism) if the
2071 completed filename contains any characters in
2072 @code{rl_filename_quote_chars}. This is @emph{always} non-zero
2073 when completion is attempted, and can only be changed within an
2074 application-specific completion function.
2075 The quoting is effected via a call to the function pointed to
2076 by @code{rl_filename_quoting_function}.
2079 @deftypevar int rl_attempted_completion_over
2080 If an application-specific completion function assigned to
2081 @code{rl_attempted_completion_function} sets this variable to a non-zero
2082 value, Readline will not perform its default filename completion even
2083 if the application's completion function returns no matches.
2084 It should be set only by an application's completion function.
2087 @deftypevar int rl_sort_completion_matches
2088 If an application sets this variable to 0, Readline will not sort the
2089 list of completions (which implies that it cannot remove any duplicate
2090 completions). The default value is 1, which means that Readline will
2091 sort the completions and, depending on the value of
2092 @code{rl_ignore_completion_duplicates}, will attempt to remove duplicate
2096 @deftypevar int rl_completion_type
2097 Set to a character describing the type of completion Readline is currently
2098 attempting; see the description of @code{rl_complete_internal()}
2099 (@pxref{Completion Functions}) for the list of characters.
2100 This is set to the appropriate value before any application-specific
2101 completion function is called, allowing such functions to present
2102 the same interface as @code{rl_complete()}.
2105 @deftypevar int rl_completion_invoking_key
2106 Set to the final character in the key sequence that invoked one of the
2107 completion functions that call @code{rl_complete_internal()}. This is
2108 set to the appropriate value before any application-specific completion
2112 @deftypevar int rl_inhibit_completion
2113 If this variable is non-zero, completion is inhibited. The completion
2114 character will be inserted as any other bound to @code{self-insert}.
2117 @node A Short Completion Example
2118 @subsection A Short Completion Example
2120 Here is a small application demonstrating the use of the GNU Readline
2121 library. It is called @code{fileman}, and the source code resides in
2122 @file{examples/fileman.c}. This sample application provides
2123 completion of command names, line editing features, and access to the
2128 /* fileman.c -- A tiny application which demonstrates how to use the
2129 GNU Readline library. This application interactively allows users
2130 to manipulate files and their modes. */
2132 #ifdef HAVE_CONFIG_H
2133 # include <config.h>
2136 #include <sys/types.h>
2137 #ifdef HAVE_SYS_FILE_H
2138 # include <sys/file.h>
2140 #include <sys/stat.h>
2142 #ifdef HAVE_UNISTD_H
2143 # include <unistd.h>
2150 #if defined (HAVE_STRING_H)
2151 # include <string.h>
2152 #else /* !HAVE_STRING_H */
2153 # include <strings.h>
2154 #endif /* !HAVE_STRING_H */
2156 #ifdef HAVE_STDLIB_H
2157 # include <stdlib.h>
2162 #include <readline/readline.h>
2163 #include <readline/history.h>
2165 extern char *xmalloc PARAMS((size_t));
2167 /* The names of functions that actually do the manipulation. */
2168 int com_list PARAMS((char *));
2169 int com_view PARAMS((char *));
2170 int com_rename PARAMS((char *));
2171 int com_stat PARAMS((char *));
2172 int com_pwd PARAMS((char *));
2173 int com_delete PARAMS((char *));
2174 int com_help PARAMS((char *));
2175 int com_cd PARAMS((char *));
2176 int com_quit PARAMS((char *));
2178 /* A structure which contains information on the commands this program
2182 char *name; /* User printable name of the function. */
2183 rl_icpfunc_t *func; /* Function to call to do the job. */
2184 char *doc; /* Documentation for this function. */
2187 COMMAND commands[] = @{
2188 @{ "cd", com_cd, "Change to directory DIR" @},
2189 @{ "delete", com_delete, "Delete FILE" @},
2190 @{ "help", com_help, "Display this text" @},
2191 @{ "?", com_help, "Synonym for `help'" @},
2192 @{ "list", com_list, "List files in DIR" @},
2193 @{ "ls", com_list, "Synonym for `list'" @},
2194 @{ "pwd", com_pwd, "Print the current working directory" @},
2195 @{ "quit", com_quit, "Quit using Fileman" @},
2196 @{ "rename", com_rename, "Rename FILE to NEWNAME" @},
2197 @{ "stat", com_stat, "Print out statistics on FILE" @},
2198 @{ "view", com_view, "View the contents of FILE" @},
2199 @{ (char *)NULL, (rl_icpfunc_t *)NULL, (char *)NULL @}
2202 /* Forward declarations. */
2203 char *stripwhite ();
2204 COMMAND *find_command ();
2206 /* The name of this program, as taken from argv[0]. */
2209 /* When non-zero, this global means the user is done using this program. */
2218 r = xmalloc (strlen (s) + 1);
2231 initialize_readline (); /* Bind our completer. */
2233 /* Loop reading and executing lines until the user quits. */
2234 for ( ; done == 0; )
2236 line = readline ("FileMan: ");
2241 /* Remove leading and trailing whitespace from the line.
2242 Then, if there is anything left, add it to the history list
2244 s = stripwhite (line);
2257 /* Execute a command line. */
2266 /* Isolate the command word. */
2268 while (line[i] && whitespace (line[i]))
2272 while (line[i] && !whitespace (line[i]))
2278 command = find_command (word);
2282 fprintf (stderr, "%s: No such command for FileMan.\n", word);
2286 /* Get argument to command, if any. */
2287 while (whitespace (line[i]))
2292 /* Call the function. */
2293 return ((*(command->func)) (word));
2296 /* Look up NAME as the name of a command, and return a pointer to that
2297 command. Return a NULL pointer if NAME isn't a command name. */
2304 for (i = 0; commands[i].name; i++)
2305 if (strcmp (name, commands[i].name) == 0)
2306 return (&commands[i]);
2308 return ((COMMAND *)NULL);
2311 /* Strip whitespace from the start and end of STRING. Return a pointer
2317 register char *s, *t;
2319 for (s = string; whitespace (*s); s++)
2325 t = s + strlen (s) - 1;
2326 while (t > s && whitespace (*t))
2333 /* **************************************************************** */
2335 /* Interface to Readline Completion */
2337 /* **************************************************************** */
2339 char *command_generator PARAMS((const char *, int));
2340 char **fileman_completion PARAMS((const char *, int, int));
2342 /* Tell the GNU Readline library how to complete. We want to try to complete
2343 on command names if this is the first word in the line, or on filenames
2345 initialize_readline ()
2347 /* Allow conditional parsing of the ~/.inputrc file. */
2348 rl_readline_name = "FileMan";
2350 /* Tell the completer that we want a crack first. */
2351 rl_attempted_completion_function = fileman_completion;
2354 /* Attempt to complete on the contents of TEXT. START and END bound the
2355 region of rl_line_buffer that contains the word to complete. TEXT is
2356 the word to complete. We can use the entire contents of rl_line_buffer
2357 in case we want to do some simple parsing. Return the array of matches,
2358 or NULL if there aren't any. */
2360 fileman_completion (text, start, end)
2366 matches = (char **)NULL;
2368 /* If this word is at the start of the line, then it is a command
2369 to complete. Otherwise it is the name of a file in the current
2372 matches = rl_completion_matches (text, command_generator);
2377 /* Generator function for command completion. STATE lets us know whether
2378 to start from scratch; without any state (i.e. STATE == 0), then we
2379 start at the top of the list. */
2381 command_generator (text, state)
2385 static int list_index, len;
2388 /* If this is a new word to complete, initialize now. This includes
2389 saving the length of TEXT for efficiency, and initializing the index
2394 len = strlen (text);
2397 /* Return the next name which partially matches from the command list. */
2398 while (name = commands[list_index].name)
2402 if (strncmp (name, text, len) == 0)
2403 return (dupstr(name));
2406 /* If no names matched, then return NULL. */
2407 return ((char *)NULL);
2410 /* **************************************************************** */
2412 /* FileMan Commands */
2414 /* **************************************************************** */
2416 /* String to pass to system (). This is for the LIST, VIEW and RENAME
2418 static char syscom[1024];
2420 /* List the file(s) named in arg. */
2427 sprintf (syscom, "ls -FClg %s", arg);
2428 return (system (syscom));
2434 if (!valid_argument ("view", arg))
2437 #if defined (__MSDOS__)
2438 /* more.com doesn't grok slashes in pathnames */
2439 sprintf (syscom, "less %s", arg);
2441 sprintf (syscom, "more %s", arg);
2443 return (system (syscom));
2449 too_dangerous ("rename");
2458 if (!valid_argument ("stat", arg))
2461 if (stat (arg, &finfo) == -1)
2467 printf ("Statistics for `%s':\n", arg);
2469 printf ("%s has %d link%s, and is %d byte%s in length.\n",
2472 (finfo.st_nlink == 1) ? "" : "s",
2474 (finfo.st_size == 1) ? "" : "s");
2475 printf ("Inode Last Change at: %s", ctime (&finfo.st_ctime));
2476 printf (" Last access at: %s", ctime (&finfo.st_atime));
2477 printf (" Last modified at: %s", ctime (&finfo.st_mtime));
2484 too_dangerous ("delete");
2488 /* Print out help for ARG, or for all of the commands if ARG is
2496 for (i = 0; commands[i].name; i++)
2498 if (!*arg || (strcmp (arg, commands[i].name) == 0))
2500 printf ("%s\t\t%s.\n", commands[i].name, commands[i].doc);
2507 printf ("No commands match `%s'. Possibilties are:\n", arg);
2509 for (i = 0; commands[i].name; i++)
2511 /* Print in six columns. */
2518 printf ("%s\t", commands[i].name);
2528 /* Change to the directory ARG. */
2532 if (chdir (arg) == -1)
2542 /* Print out the current working directory. */
2548 s = getcwd (dir, sizeof(dir) - 1);
2551 printf ("Error getting pwd: %s\n", dir);
2555 printf ("Current directory is %s\n", dir);
2559 /* The user wishes to quit using this program. Just set DONE non-zero. */
2567 /* Function which tells you that you can't do this. */
2568 too_dangerous (caller)
2572 "%s: Too dangerous for me to distribute. Write it yourself.\n",
2576 /* Return non-zero if ARG is a valid argument for CALLER, else print
2577 an error message and return zero. */
2579 valid_argument (caller, arg)
2584 fprintf (stderr, "%s: Argument required.\n", caller);