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@setfilename rltech.info

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@ifinfo

This document describes the GNU Readline Library, a utility for aiding

in the consistency of user interface across discrete programs that need

to provide a command line interface.

Copyright (C) 1988-2005 Free Software Foundation, Inc.

Permission is granted to make and distribute verbatim copies of

this manual provided the copyright notice and this permission notice

pare preserved on all copies.

@ignore

Permission is granted to process this file through TeX and print the

results, provided the printed document carries copying permission

notice identical to this one except for the removal of this paragraph

(this paragraph not being relevant to the printed manual).

@end ignore

Permission is granted to copy and distribute modified versions of this

manual under the conditions for verbatim copying, provided that the entire

resulting derived work is distributed under the terms of a permission

notice identical to this one.

Permission is granted to copy and distribute translations of this manual

into another language, under the above conditions for modified versions,

except that this permission notice may be stated in a translation approved

by the Foundation.

@end ifinfo

@node Programming with GNU Readline

@chapter Programming with GNU Readline

This chapter describes the interface between the @sc{gnu} Readline Library and

other programs.  If you are a programmer, and you wish to include the

features found in @sc{gnu} Readline

such as completion, line editing, and interactive history manipulation

in your own programs, this section is for you.

@menu

* Basic Behavior::      Using the default behavior of Readline.

* Custom Functions::    Adding your own functions to Readline.

* Readline Variables::                  Variables accessible to custom

                                        functions.

* Readline Convenience Functions::      Functions which Readline supplies to

                                        aid in writing your own custom

                                        functions.

* Readline Signal Handling::    How Readline behaves when it receives signals.

* Custom Completers::   Supplanting or supplementing Readline's

                        completion functions.

@end menu

@node Basic Behavior

@section Basic Behavior

Many programs provide a command line interface, such as @code{mail},

@code{ftp}, and @code{sh}.  For such programs, the default behaviour of

Readline is sufficient.  This section describes how to use Readline in

the simplest way possible, perhaps to replace calls in your code to

@code{gets()} or @code{fgets()}.

@findex readline

@cindex readline, function

The function @code{readline()} prints a prompt @var{prompt}

and then reads and returns a single line of text from the user.

If @var{prompt} is @code{NULL} or the empty string, no prompt is displayed.

The line @code{readline} returns is allocated with @code{malloc()};

the caller should @code{free()} the line when it has finished with it.

The declaration for @code{readline} in ANSI C is

@example

@code{char *readline (const char *@var{prompt});}

@end example

@noindent

So, one might say

@example

@code{char *line = readline ("Enter a line: ");}

@end example

@noindent

in order to read a line of text from the user.

The line returned has the final newline removed, so only the

text remains.

If @code{readline} encounters an @code{EOF} while reading the line, and the

line is empty at that point, then @code{(char *)NULL} is returned.

Otherwise, the line is ended just as if a newline had been typed.

If you want the user to be able to get at the line later, (with

@key{C-p} for example), you must call @code{add_history()} to save the

line away in a @dfn{history} list of such lines.

@example

@code{add_history (line)};

@end example

@noindent

For full details on the GNU History Library, see the associated manual.

It is preferable to avoid saving empty lines on the history list, since

users rarely have a burning need to reuse a blank line.  Here is

a function which usefully replaces the standard @code{gets()} library

function, and has the advantage of no static buffer to overflow:

@example

/* A static variable for holding the line. */

static char *line_read = (char *)NULL;

/* Read a string, and return a pointer to it.

   Returns NULL on EOF. */

char *

rl_gets ()

@{

  /* If the buffer has already been allocated,

     return the memory to the free pool. */

  if (line_read)

    @{

      free (line_read);

      line_read = (char *)NULL;

    @}

  /* Get a line from the user. */

  line_read = readline ("");

  /* If the line has any text in it,

     save it on the history. */

  if (line_read && *line_read)

    add_history (line_read);

  return (line_read);

@}

@end example

This function gives the user the default behaviour of @key{TAB}

completion: completion on file names.  If you do not want Readline to

complete on filenames, you can change the binding of the @key{TAB} key

with @code{rl_bind_key()}.

@example

@code{int rl_bind_key (int @var{key}, rl_command_func_t *@var{function});}

@end example

@code{rl_bind_key()} takes two arguments: @var{key} is the character that

you want to bind, and @var{function} is the address of the function to

call when @var{key} is pressed.  Binding @key{TAB} to @code{rl_insert()}

makes @key{TAB} insert itself.

@code{rl_bind_key()} returns non-zero if @var{key} is not a valid

ASCII character code (between 0 and 255).

Thus, to disable the default @key{TAB} behavior, the following suffices:

@example

@code{rl_bind_key ('\t', rl_insert);}

@end example

This code should be executed once at the start of your program; you

might write a function called @code{initialize_readline()} which

performs this and other desired initializations, such as installing

custom completers (@pxref{Custom Completers}).

@node Custom Functions

@section Custom Functions

Readline provides many functions for manipulating the text of

the line, but it isn't possible to anticipate the needs of all

programs.  This section describes the various functions and variables

defined within the Readline library which allow a user program to add

customized functionality to Readline.

Before declaring any functions that customize Readline's behavior, or

using any functionality Readline provides in other code, an

application writer should include the file @code{<readline/readline.h>}

in any file that uses Readline's features.  Since some of the definitions

in @code{readline.h} use the @code{stdio} library, the file

@code{<stdio.h>} should be included before @code{readline.h}.

@code{readline.h} defines a C preprocessor variable that should

be treated as an integer, @code{RL_READLINE_VERSION}, which may

be used to conditionally compile application code depending on

the installed Readline version.  The value is a hexadecimal

encoding of the major and minor version numbers of the library,

of the form 0x@var{MMmm}.  @var{MM} is the two-digit major

version number; @var{mm} is the two-digit minor version number.

For Readline 4.2, for example, the value of

@code{RL_READLINE_VERSION} would be @code{0x0402}.

@menu

* Readline Typedefs::   C declarations to make code readable.

* Function Writing::    Variables and calling conventions.

@end menu

@node Readline Typedefs

@subsection Readline Typedefs

For readabilty, we declare a number of new object types, all pointers

to functions.

The reason for declaring these new types is to make it easier to write

code describing pointers to C functions with appropriately prototyped

arguments and return values.

For instance, say we want to declare a variable @var{func} as a pointer

to a function which takes two @code{int} arguments and returns an

@code{int} (this is the type of all of the Readline bindable functions).

Instead of the classic C declaration

@code{int (*func)();}

@noindent

or the ANSI-C style declaration

@code{int (*func)(int, int);}

@noindent

we may write

@code{rl_command_func_t *func;}

The full list of function pointer types available is

@table @code

@item typedef int rl_command_func_t (int, int);

@item typedef char *rl_compentry_func_t (const char *, int);

@item typedef char **rl_completion_func_t (const char *, int, int);

@item typedef char *rl_quote_func_t (char *, int, char *);

@item typedef char *rl_dequote_func_t (char *, int);

@item typedef int rl_compignore_func_t (char **);

@item typedef void rl_compdisp_func_t (char **, int, int);

@item typedef int rl_hook_func_t (void);

@item typedef int rl_getc_func_t (FILE *);

@item typedef int rl_linebuf_func_t (char *, int);

@item typedef int rl_intfunc_t (int);

@item #define rl_ivoidfunc_t rl_hook_func_t

@item typedef int rl_icpfunc_t (char *);

@item typedef int rl_icppfunc_t (char **);

@item typedef void rl_voidfunc_t (void);

@item typedef void rl_vintfunc_t (int);

@item typedef void rl_vcpfunc_t (char *);

@item typedef void rl_vcppfunc_t (char **);

@end table

@node Function Writing

@subsection Writing a New Function

In order to write new functions for Readline, you need to know the

calling conventions for keyboard-invoked functions, and the names of the

variables that describe the current state of the line read so far.

The calling sequence for a command @code{foo} looks like

@example

@code{int foo (int count, int key)}

@end example

@noindent

where @var{count} is the numeric argument (or 1 if defaulted) and

@var{key} is the key that invoked this function.

It is completely up to the function as to what should be done with the

numeric argument.  Some functions use it as a repeat count, some

as a flag, and others to choose alternate behavior (refreshing the current

line as opposed to refreshing the screen, for example).  Some choose to

ignore it.  In general, if a

function uses the numeric argument as a repeat count, it should be able

to do something useful with both negative and positive arguments.

At the very least, it should be aware that it can be passed a

negative argument.

A command function should return 0 if its action completes successfully,

and a non-zero value if some error occurs.

This is the convention obeyed by all of the builtin Readline bindable

command functions.

@node Readline Variables

@section Readline Variables

These variables are available to function writers.

@deftypevar {char *} rl_line_buffer

This is the line gathered so far.  You are welcome to modify the

contents of the line, but see @ref{Allowing Undoing}.  The

function @code{rl_extend_line_buffer} is available to increase

the memory allocated to @code{rl_line_buffer}.

@end deftypevar

@deftypevar int rl_point

The offset of the current cursor position in @code{rl_line_buffer}

(the @emph{point}).

@end deftypevar

@deftypevar int rl_end

The number of characters present in @code{rl_line_buffer}.  When

@code{rl_point} is at the end of the line, @code{rl_point} and

@code{rl_end} are equal.

@end deftypevar

@deftypevar int rl_mark

The @var{mark} (saved position) in the current line.  If set, the mark

and point define a @emph{region}.

@end deftypevar

@deftypevar int rl_done

Setting this to a non-zero value causes Readline to return the current

line immediately.

@end deftypevar

@deftypevar int rl_num_chars_to_read

Setting this to a positive value before calling @code{readline()} causes

Readline to return after accepting that many characters, rather

than reading up to a character bound to @code{accept-line}.

@end deftypevar

@deftypevar int rl_pending_input

Setting this to a value makes it the next keystroke read.  This is a

way to stuff a single character into the input stream.

@end deftypevar

@deftypevar int rl_dispatching

Set to a non-zero value if a function is being called from a key binding;

zero otherwise.  Application functions can test this to discover whether

they were called directly or by Readline's dispatching mechanism.

@end deftypevar

@deftypevar int rl_erase_empty_line

Setting this to a non-zero value causes Readline to completely erase

the current line, including any prompt, any time a newline is typed as

the only character on an otherwise-empty line.  The cursor is moved to

the beginning of the newly-blank line.

@end deftypevar

@deftypevar {char *} rl_prompt

The prompt Readline uses.  This is set from the argument to

@code{readline()}, and should not be assigned to directly.

The @code{rl_set_prompt()} function (@pxref{Redisplay}) may

be used to modify the prompt string after calling @code{readline()}.

@end deftypevar

@deftypevar int rl_already_prompted

If an application wishes to display the prompt itself, rather than have

Readline do it the first time @code{readline()} is called, it should set

this variable to a non-zero value after displaying the prompt.

The prompt must also be passed as the argument to @code{readline()} so

the redisplay functions can update the display properly.

The calling application is responsible for managing the value; Readline

never sets it.

@end deftypevar

@deftypevar {const char *} rl_library_version

The version number of this revision of the library.

@end deftypevar

@deftypevar int rl_readline_version

An integer encoding the current version of the library.  The encoding is

of the form 0x@var{MMmm}, where @var{MM} is the two-digit major version

number, and @var{mm} is the two-digit minor version number.

For example, for Readline-4.2, @code{rl_readline_version} would have the

value 0x0402.

@end deftypevar

@deftypevar {int} rl_gnu_readline_p

Always set to 1, denoting that this is @sc{gnu} readline rather than some

emulation.

@end deftypevar

@deftypevar {const char *} rl_terminal_name

The terminal type, used for initialization.  If not set by the application,

Readline sets this to the value of the @env{TERM} environment variable

the first time it is called.

@end deftypevar

@deftypevar {const char *} rl_readline_name

This variable is set to a unique name by each application using Readline.

The value allows conditional parsing of the inputrc file

(@pxref{Conditional Init Constructs}).

@end deftypevar

@deftypevar {FILE *} rl_instream

The stdio stream from which Readline reads input.

If @code{NULL}, Readline defaults to @var{stdin}.

@end deftypevar

@deftypevar {FILE *} rl_outstream

The stdio stream to which Readline performs output.

If @code{NULL}, Readline defaults to @var{stdout}.

@end deftypevar

@deftypevar int rl_prefer_env_winsize

If non-zero, Readline gives values found in the @env{LINES} and

@env{COLUMNS} environment variables greater precedence than values fetched

from the kernel when computing the screen dimensions.

@end deftypevar

@deftypevar {rl_command_func_t *} rl_last_func

The address of the last command function Readline executed.  May be used to

test whether or not a function is being executed twice in succession, for

example.

@end deftypevar

@deftypevar {rl_hook_func_t *} rl_startup_hook

If non-zero, this is the address of a function to call just

before @code{readline} prints the first prompt.

@end deftypevar

@deftypevar {rl_hook_func_t *} rl_pre_input_hook

If non-zero, this is the address of a function to call after

the first prompt has been printed and just before @code{readline}

starts reading input characters.

@end deftypevar

@deftypevar {rl_hook_func_t *} rl_event_hook

If non-zero, this is the address of a function to call periodically

when Readline is waiting for terminal input.

By default, this will be called at most ten times a second if there

is no keyboard input.

@end deftypevar

@deftypevar {rl_getc_func_t *} rl_getc_function

If non-zero, Readline will call indirectly through this pointer

to get a character from the input stream.  By default, it is set to

@code{rl_getc}, the default Readline character input function

(@pxref{Character Input}).

@end deftypevar

@deftypevar {rl_voidfunc_t *} rl_redisplay_function

If non-zero, Readline will call indirectly through this pointer

to update the display with the current contents of the editing buffer.

By default, it is set to @code{rl_redisplay}, the default Readline

redisplay function (@pxref{Redisplay}).

@end deftypevar

@deftypevar {rl_vintfunc_t *} rl_prep_term_function

If non-zero, Readline will call indirectly through this pointer

to initialize the terminal.  The function takes a single argument, an

@code{int} flag that says whether or not to use eight-bit characters.

By default, this is set to @code{rl_prep_terminal}

(@pxref{Terminal Management}).

@end deftypevar

@deftypevar {rl_voidfunc_t *} rl_deprep_term_function

If non-zero, Readline will call indirectly through this pointer

to reset the terminal.  This function should undo the effects of

@code{rl_prep_term_function}.

By default, this is set to @code{rl_deprep_terminal}

(@pxref{Terminal Management}).

@end deftypevar

@deftypevar {Keymap} rl_executing_keymap

This variable is set to the keymap (@pxref{Keymaps}) in which the

currently executing readline function was found.

@end deftypevar

@deftypevar {Keymap} rl_binding_keymap

This variable is set to the keymap (@pxref{Keymaps}) in which the

last key binding occurred.

@end deftypevar

@deftypevar {char *} rl_executing_macro

This variable is set to the text of any currently-executing macro.

@end deftypevar

@deftypevar {int} rl_readline_state

A variable with bit values that encapsulate the current Readline state.

A bit is set with the @code{RL_SETSTATE} macro, and unset with the

@code{RL_UNSETSTATE} macro.  Use the @code{RL_ISSTATE} macro to test

whether a particular state bit is set.  Current state bits include:

@table @code

@item RL_STATE_NONE

Readline has not yet been called, nor has it begun to intialize.

@item RL_STATE_INITIALIZING

Readline is initializing its internal data structures.

@item RL_STATE_INITIALIZED

Readline has completed its initialization.

@item RL_STATE_TERMPREPPED

Readline has modified the terminal modes to do its own input and redisplay.

@item RL_STATE_READCMD

Readline is reading a command from the keyboard.

@item RL_STATE_METANEXT

Readline is reading more input after reading the meta-prefix character.

@item RL_STATE_DISPATCHING

Readline is dispatching to a command.

@item RL_STATE_MOREINPUT

Readline is reading more input while executing an editing command.

@item RL_STATE_ISEARCH

Readline is performing an incremental history search.

@item RL_STATE_NSEARCH

Readline is performing a non-incremental history search.

@item RL_STATE_SEARCH

Readline is searching backward or forward through the history for a string.

@item RL_STATE_NUMERICARG

Readline is reading a numeric argument.

@item RL_STATE_MACROINPUT

Readline is currently getting its input from a previously-defined keyboard

macro.

@item RL_STATE_MACRODEF

Readline is currently reading characters defining a keyboard macro.

@item RL_STATE_OVERWRITE

Readline is in overwrite mode.

@item RL_STATE_COMPLETING

Readline is performing word completion.

@item RL_STATE_SIGHANDLER

Readline is currently executing the readline signal handler.

@item RL_STATE_UNDOING

Readline is performing an undo.

@item RL_STATE_DONE

Readline has read a key sequence bound to @code{accept-line}

and is about to return the line to the caller.

@end table

@end deftypevar

@deftypevar {int} rl_explicit_arg

Set to a non-zero value if an explicit numeric argument was specified by

the user.  Only valid in a bindable command function.

@end deftypevar

@deftypevar {int} rl_numeric_arg

Set to the value of any numeric argument explicitly specified by the user

before executing the current Readline function.  Only valid in a bindable

command function.

@end deftypevar

@deftypevar {int} rl_editing_mode

Set to a value denoting Readline's current editing mode.  A value of

@var{1} means Readline is currently in emacs mode; @var{0}

means that vi mode is active.

@end deftypevar

@node Readline Convenience Functions

@section Readline Convenience Functions

@menu

* Function Naming::     How to give a function you write a name.

* Keymaps::             Making keymaps.

* Binding Keys::        Changing Keymaps.

* Associating Function Names and Bindings::     Translate function names to

                                                key sequences.

* Allowing Undoing::    How to make your functions undoable.

* Redisplay::           Functions to control line display.

* Modifying Text::      Functions to modify @code{rl_line_buffer}.

* Character Input::     Functions to read keyboard input.

* Terminal Management:: Functions to manage terminal settings.

* Utility Functions::   Generally useful functions and hooks.

* Miscellaneous Functions::     Functions that don't fall into any category.

* Alternate Interface:: Using Readline in a `callback' fashion.

* A Readline Example::          An example Readline function.

@end menu

@node Function Naming

@subsection Naming a Function

The user can dynamically change the bindings of keys while using

Readline.  This is done by representing the function with a descriptive

name.  The user is able to type the descriptive name when referring to

the function.  Thus, in an init file, one might find

@example

Meta-Rubout:    backward-kill-word

@end example

This binds the keystroke @key{Meta-Rubout} to the function

@emph{descriptively} named @code{backward-kill-word}.  You, as the

programmer, should bind the functions you write to descriptive names as

well.  Readline provides a function for doing that:

@deftypefun int rl_add_defun (const char *name, rl_command_func_t *function, int key)

Add @var{name} to the list of named functions.  Make @var{function} be

the function that gets called.  If @var{key} is not -1, then bind it to

@var{function} using @code{rl_bind_key()}.

@end deftypefun

Using this function alone is sufficient for most applications.

It is the recommended way to add a few functions to the default

functions that Readline has built in.

If you need to do something other than adding a function to Readline,

you may need to use the underlying functions described below.

@node Keymaps

@subsection Selecting a Keymap

Key bindings take place on a @dfn{keymap}.  The keymap is the

association between the keys that the user types and the functions that

get run.  You can make your own keymaps, copy existing keymaps, and tell

Readline which keymap to use.

@deftypefun Keymap rl_make_bare_keymap (void)

Returns a new, empty keymap.  The space for the keymap is allocated with

@code{malloc()}; the caller should free it by calling

@code{rl_discard_keymap()} when done.

@end deftypefun

@deftypefun Keymap rl_copy_keymap (Keymap map)

Return a new keymap which is a copy of @var{map}.

@end deftypefun

@deftypefun Keymap rl_make_keymap (void)

Return a new keymap with the printing characters bound to rl_insert,

the lowercase Meta characters bound to run their equivalents, and

the Meta digits bound to produce numeric arguments.

@end deftypefun

@deftypefun void rl_discard_keymap (Keymap keymap)

Free the storage associated with @var{keymap}.

@end deftypefun

Readline has several internal keymaps.  These functions allow you to

change which keymap is active.

@deftypefun Keymap rl_get_keymap (void)

Returns the currently active keymap.

@end deftypefun

@deftypefun void rl_set_keymap (Keymap keymap)

Makes @var{keymap} the currently active keymap.

@end deftypefun

@deftypefun Keymap rl_get_keymap_by_name (const char *name)

Return the keymap matching @var{name}.  @var{name} is one which would

be supplied in a @code{set keymap} inputrc line (@pxref{Readline Init File}).

@end deftypefun

@deftypefun {char *} rl_get_keymap_name (Keymap keymap)

Return the name matching @var{keymap}.  @var{name} is one which would

be supplied in a @code{set keymap} inputrc line (@pxref{Readline Init File}).

@end deftypefun

@node Binding Keys

@subsection Binding Keys

Key sequences are associate with functions through the keymap.

Readline has several internal keymaps: @code{emacs_standard_keymap},

@code{emacs_meta_keymap}, @code{emacs_ctlx_keymap},

@code{vi_movement_keymap}, and @code{vi_insertion_keymap}.

@code{emacs_standard_keymap} is the default, and the examples in

this manual assume that.

Since @code{readline()} installs a set of default key bindings the first

time it is called, there is always the danger that a custom binding

installed before the first call to @code{readline()} will be overridden.

An alternate mechanism is to install custom key bindings in an

initialization function assigned to the @code{rl_startup_hook} variable

(@pxref{Readline Variables}).

These functions manage key bindings.

@deftypefun int rl_bind_key (int key, rl_command_func_t *function)

Binds @var{key} to @var{function} in the currently active keymap.

Returns non-zero in the case of an invalid @var{key}.

@end deftypefun

@deftypefun int rl_bind_key_in_map (int key, rl_command_func_t *function, Keymap map)

Bind @var{key} to @var{function} in @var{map}.

Returns non-zero in the case of an invalid @var{key}.

@end deftypefun

@deftypefun int rl_bind_key_if_unbound (int key, rl_command_func_t *function)

Binds @var{key} to @var{function} if it is not already bound in the

currently active keymap.

Returns non-zero in the case of an invalid @var{key} or if @var{key} is

already bound.

@end deftypefun

@deftypefun int rl_bind_key_if_unbound_in_map (int key, rl_command_func_t *function, Keymap map)

Binds @var{key} to @var{function} if it is not already bound in @var{map}.

Returns non-zero in the case of an invalid @var{key} or if @var{key} is

already bound.

@end deftypefun

@deftypefun int rl_unbind_key (int key)

Bind @var{key} to the null function in the currently active keymap.

Returns non-zero in case of error.

@end deftypefun

@deftypefun int rl_unbind_key_in_map (int key, Keymap map)

Bind @var{key} to the null function in @var{map}.

Returns non-zero in case of error.

@end deftypefun

@deftypefun int rl_unbind_function_in_map (rl_command_func_t *function, Keymap map)

Unbind all keys that execute @var{function} in @var{map}.

@end deftypefun

@deftypefun int rl_unbind_command_in_map (const char *command, Keymap map)

Unbind all keys that are bound to @var{command} in @var{map}.

@end deftypefun

@deftypefun int rl_bind_keyseq (const char *keyseq, rl_command_func_t *function)

Bind the key sequence represented by the string @var{keyseq} to the function

@var{function}, beginning in the current keymap.

This makes new keymaps as necessary.

The return value is non-zero if @var{keyseq} is invalid.

@end deftypefun

@deftypefun int rl_bind_keyseq_in_map (const char *keyseq, rl_command_func_t *function, Keymap map)

Bind the key sequence represented by the string @var{keyseq} to the function

@var{function}.  This makes new keymaps as necessary.

Initial bindings are performed in @var{map}.

The return value is non-zero if @var{keyseq} is invalid.

@end deftypefun

@deftypefun int rl_set_key (const char *keyseq, rl_command_func_t *function, Keymap map)

Equivalent to @code{rl_bind_keyseq_in_map}.

@end deftypefun

@deftypefun int rl_bind_keyseq_if_unbound (const char *keyseq, rl_command_func_t *function)

Binds @var{keyseq} to @var{function} if it is not already bound in the

currently active keymap.

Returns non-zero in the case of an invalid @var{keyseq} or if @var{keyseq} is

already bound.

@end deftypefun

@deftypefun int rl_bind_keyseq_if_unbound_in_map (const char *keyseq, rl_command_func_t *function, Keymap map)

Binds @var{keyseq} to @var{function} if it is not already bound in @var{map}.

Returns non-zero in the case of an invalid @var{keyseq} or if @var{keyseq} is

already bound.

@end deftypefun

@deftypefun int rl_generic_bind (int type, const char *keyseq, char *data, Keymap map)

Bind the key sequence represented by the string @var{keyseq} to the arbitrary

pointer @var{data}.  @var{type} says what kind of data is pointed to by

@var{data}; this can be a function (@code{ISFUNC}), a macro

(@code{ISMACR}), or a keymap (@code{ISKMAP}).  This makes new keymaps as

necessary.  The initial keymap in which to do bindings is @var{map}.

@end deftypefun

@deftypefun int rl_parse_and_bind (char *line)

Parse @var{line} as if it had been read from the @code{inputrc} file and

perform any key bindings and variable assignments found

(@pxref{Readline Init File}).

@end deftypefun

@deftypefun int rl_read_init_file (const char *filename)

Read keybindings and variable assignments from @var{filename}

(@pxref{Readline Init File}).

@end deftypefun

@node Associating Function Names and Bindings

@subsection Associating Function Names and Bindings

These functions allow you to find out what keys invoke named functions

and the functions invoked by a particular key sequence.  You may also

associate a new function name with an arbitrary function.

@deftypefun {rl_command_func_t *} rl_named_function (const char *name)

Return the function with name @var{name}.

@end deftypefun

@deftypefun {rl_command_func_t *} rl_function_of_keyseq (const char *keyseq, Keymap map, int *type)

Return the function invoked by @var{keyseq} in keymap @var{map}.

If @var{map} is @code{NULL}, the current keymap is used.  If @var{type} is

not @code{NULL}, the type of the object is returned in the @code{int} variable

it points to (one of @code{ISFUNC}, @code{ISKMAP}, or @code{ISMACR}).

@end deftypefun

@deftypefun {char **} rl_invoking_keyseqs (rl_command_func_t *function)

Return an array of strings representing the key sequences used to

invoke @var{function} in the current keymap.

@end deftypefun

@deftypefun {char **} rl_invoking_keyseqs_in_map (rl_command_func_t *function, Keymap map)

Return an array of strings representing the key sequences used to

invoke @var{function} in the keymap @var{map}.

@end deftypefun

@deftypefun void rl_function_dumper (int readable)

Print the readline function names and the key sequences currently

bound to them to @code{rl_outstream}.  If @var{readable} is non-zero,

the list is formatted in such a way that it can be made part of an

@code{inputrc} file and re-read.

@end deftypefun

@deftypefun void rl_list_funmap_names (void)

Print the names of all bindable Readline functions to @code{rl_outstream}.

@end deftypefun

@deftypefun {const char **} rl_funmap_names (void)

Return a NULL terminated array of known function names.  The array is

sorted.  The array itself is allocated, but not the strings inside.  You

should @code{free()} the array when you are done, but not the pointers.

@end deftypefun

@deftypefun int rl_add_funmap_entry (const char *name, rl_command_func_t *function)

Add @var{name} to the list of bindable Readline command names, and make

@var{function} the function to be called when @var{name} is invoked.

@end deftypefun

@node Allowing Undoing

@subsection Allowing Undoing

Supporting the undo command is a painless thing, and makes your

functions much more useful.  It is certainly easy to try

something if you know you can undo it.

If your function simply inserts text once, or deletes text once, and

uses @code{rl_insert_text()} or @code{rl_delete_text()} to do it, then

undoing is already done for you automatically.

If you do multiple insertions or multiple deletions, or any combination

of these operations, you should group them together into one operation.

This is done with @code{rl_begin_undo_group()} and

@code{rl_end_undo_group()}.

The types of events that can be undone are:

@smallexample

enum undo_code @{ UNDO_DELETE, UNDO_INSERT, UNDO_BEGIN, UNDO_END @};

@end smallexample

Notice that @code{UNDO_DELETE} means to insert some text, and

@code{UNDO_INSERT} means to delete some text.  That is, the undo code

tells what to undo, not how to undo it.  @code{UNDO_BEGIN} and

@code{UNDO_END} are tags added by @code{rl_begin_undo_group()} and

@code{rl_end_undo_group()}.

@deftypefun int rl_begin_undo_group (void)

Begins saving undo information in a group construct.  The undo

information usually comes from calls to @code{rl_insert_text()} and

@code{rl_delete_text()}, but could be the result of calls to

@code{rl_add_undo()}.

@end deftypefun

@deftypefun int rl_end_undo_group (void)

Closes the current undo group started with @code{rl_begin_undo_group

()}.  There should be one call to @code{rl_end_undo_group()}

for each call to @code{rl_begin_undo_group()}.

@end deftypefun

@deftypefun void rl_add_undo (enum undo_code what, int start, int end, char *text)

Remember how to undo an event (according to @var{what}).  The affected

text runs from @var{start} to @var{end}, and encompasses @var{text}.

@end deftypefun

@deftypefun void rl_free_undo_list (void)

Free the existing undo list.

@end deftypefun

@deftypefun int rl_do_undo (void)

Undo the first thing on the undo list.  Returns @code{0} if there was

nothing to undo, non-zero if something was undone.

@end deftypefun

Finally, if you neither insert nor delete text, but directly modify the

existing text (e.g., change its case), call @code{rl_modifying()}

once, just before you modify the text.  You must supply the indices of

the text range that you are going to modify.

@deftypefun int rl_modifying (int start, int end)

Tell Readline to save the text between @var{start} and @var{end} as a

single undo unit.  It is assumed that you will subsequently modify

that text.

@end deftypefun

@node Redisplay

@subsection Redisplay

@deftypefun void rl_redisplay (void)

Change what's displayed on the screen to reflect the current contents

of @code{rl_line_buffer}.

@end deftypefun

@deftypefun int rl_forced_update_display (void)

Force the line to be updated and redisplayed, whether or not

Readline thinks the screen display is correct.

@end deftypefun

@deftypefun int rl_on_new_line (void)

Tell the update functions that we have moved onto a new (empty) line,

usually after ouputting a newline.

@end deftypefun

@deftypefun int rl_on_new_line_with_prompt (void)

Tell the update functions that we have moved onto a new line, with

@var{rl_prompt} already displayed.

This could be used by applications that want to output the prompt string

themselves, but still need Readline to know the prompt string length for

redisplay.

It should be used after setting @var{rl_already_prompted}.

@end deftypefun

@deftypefun int rl_reset_line_state (void)

Reset the display state to a clean state and redisplay the current line

starting on a new line.

@end deftypefun

@deftypefun int rl_crlf (void)

Move the cursor to the start of the next screen line.

@end deftypefun

@deftypefun int rl_show_char (int c)

Display character @var{c} on @code{rl_outstream}.

If Readline has not been set to display meta characters directly, this

will convert meta characters to a meta-prefixed key sequence.

This is intended for use by applications which wish to do their own

redisplay.

@end deftypefun

@deftypefun int rl_message (const char *, @dots{})

The arguments are a format string as would be supplied to @code{printf},

possibly containing conversion specifications such as @samp{%d}, and

any additional arguments necessary to satisfy the conversion specifications.

The resulting string is displayed in the @dfn{echo area}.  The echo area

is also used to display numeric arguments and search strings.

You should call @code{rl_save_prompt} to save the prompt information

before calling this function.

@end deftypefun

@deftypefun int rl_clear_message (void)

Clear the message in the echo area.  If the prompt was saved with a call to

@code{rl_save_prompt} before the last call to @code{rl_message},

call @code{rl_restore_prompt} before calling this function.

@end deftypefun

@deftypefun void rl_save_prompt (void)

Save the local Readline prompt display state in preparation for

displaying a new message in the message area with @code{rl_message()}.

@end deftypefun

@deftypefun void rl_restore_prompt (void)

Restore the local Readline prompt display state saved by the most

recent call to @code{rl_save_prompt}.

if @code{rl_save_prompt} was called to save the prompt before a call

to @code{rl_message}, this function should be called before the