El_getc (3) Linux Manual Page

NAME

editline, el_init, el_end, el_reset, el_gets, el_getc, el_push, el_parse, el_set, el_get, el_source, el_resize, el_line, el_insertstr, el_deletestr, history_init, history_end, history, tok_init, tok_end, tok_reset, tok_line, tok_str – line editor, history and tokenization functions

LIBRARY

Command Line Editor Library (libedit, -ledit)

SYNOPSIS

#include <histedit.h>

EditLine *
el_init(const char *prog, FILE *fin, FILE *fout, FILE *ferr);

void
el_end(EditLine *e);

void
el_reset(EditLine *e);

const char *
el_gets(EditLine *e, int *count);

int
el_getc(EditLine *e, char *ch);

void
el_push(EditLine *e, const char *str);

int
el_parse(EditLine *e, int argc, const char *argv[]);

int
el_set(EditLine *e, int op, …);

int
el_get(EditLine *e, int op, …);

int
el_source(EditLine *e, const char *file);

void
el_resize(EditLine *e);

const LineInfo *
el_line(EditLine *e);

int
el_insertstr(EditLine *e, const char *str);

void
el_deletestr(EditLine *e, int count);

History *
history_init();

void
history_end(History *h);

int
history(History *h, HistEvent *ev, int op, …);

Tokenizer *
tok_init(const char *IFS);

void
tok_end(Tokenizer *t);

void
tok_reset(Tokenizer *t);

int
tok_line(Tokenizer *t, const LineInfo *li, int *argc, const char **argv[], int *cursorc, int *cursoro);

int
tok_str(Tokenizer *t, const char *str, int *argc, const char **argv[]);

DESCRIPTION

The editline library provides generic line editing, history and tokenization functions, similar to those found in sh(1).

These functions are available in the libedit library (which needs the libcurses library). Programs should be linked with -ledit -lcurses.

LINE EDITING FUNCTIONS

The line editing functions use a common data structure, EditLine, which is created by el_init() and freed by el_end().

The following functions are available:

el_init()

Initialise the line editor, and return a data structure to be used by all other line editing functions. prog is the name of the invoking program, used when reading the editrc(5) file to determine which settings to use. fin, fout and ferr are the input, output, and error streams (respectively) to use. In this documentation, references to “the tty” are actually to this input/output stream combination.

el_end()

Clean up and finish with e, assumed to have been created with el_init().

el_reset()

Reset the tty and the parser. This should be called after an error which may have upset the tty’s state.

el_gets()

Read a line from the tty. count is modified to contain the number of characters read. Returns the line read if successful, or NULL if no characters were read or if an error occurred.

el_getc()

Read a character from the tty. ch is modified to contain the character read. Returns the number of characters read if successful, -1 otherwise.

el_push()

Pushes str back onto the input stream. This is used by the macro expansion mechanism. Refer to the description of bind -s in editrc(5) for more information.

el_parse()

Parses the argv array (which is argc elements in size) to execute builtin editline commands. If the command is prefixed with “prog :” then el_parse() will only execute the command if “prog” matches the prog argument supplied to el_init(). The return value is -1 if the command is unknown, 0 if there was no error or “prog” didn’t match, or 1 if the command returned an error. Refer to editrc(5) for more information.

el_set()

Set editline parameters. op determines which parameter to set, and each operation has its own parameter list.

The following values for op are supported, along with the required argument list:

EL_PROMPT , char *(*f)(EditLine *)

Define prompt printing function as f, which is to return a string that contains the prompt.

EL_REFRESH

Re-display the current line on the next terminal line.

EL_RPROMPT , char *(*f)(EditLine *)

Define right side prompt printing function as f, which is to return a string that contains the prompt.

EL_TERMINAL , const char *type

Define terminal type of the tty to be type, or to TERM if type is NULL .

EL_EDITOR , const char *mode

Set editing mode to mode, which must be one of “emacs” or “vi”.

EL_SIGNAL , int flag

If flag is non-zero, editline will install its own signal handler for the following signals when reading command input: SIGCONT , SIGHUP , SIGINT , SIGQUIT , SIGSTOP , SIGTERM , SIGTSTP , and SIGWINCH . Otherwise, the current signal handlers will be used.

EL_BIND , const char *, …, NULL

Perform the bind builtin command. Refer to editrc(5) for more information.

EL_ECHOTC , const char *, …, NULL

Perform the echotc builtin command. Refer to editrc(5) for more information.

EL_SETTC , const char *, …, NULL

Perform the settc builtin command. Refer to editrc(5) for more information.

EL_SETTY , const char *, …, NULL

Perform the setty builtin command. Refer to editrc(5) for more information.

EL_TELLTC , const char *, …, NULL

Perform the telltc builtin command. Refer to editrc(5) for more information.

EL_ADDFN , const char *name, const char *help, unsigned char (*func)(EditLine *e, int ch)

Add a user defined function, func(), referred to as name which is invoked when a key which is bound to name is entered. help is a description of name. At invocation time, ch is the key which caused the invocation. The return value of func() should be one of:

CC_NORM: Add a normal character.
CC_NEWLINE: End of line was entered.
CC_EOF: EOF was entered.
CC_ARGHACK: Expecting further command input as arguments, do nothing visually.
CC_REFRESH: Refresh display.
CC_REFRESH_BEEP: Refresh display, and beep.
CC_CURSOR: Cursor moved, so update and perform CC_REFRESH .
CC_REDISPLAY: Redisplay entire input line. This is useful if a key binding outputs extra information.
CC_ERROR: An error occurred. Beep, and flush tty.
CC_FATAL: Fatal error, reset tty to known state.

EL_HIST , History *(*func)(History *, int op, …), const char *ptr

Defines which history function to use, which is usually history(). ptr should be the value returned by history_init().

EL_EDITMODE , int flag

If flag is non-zero, editing is enabled (the default). Note that this is only an indication, and does not affect the operation of . At this time, it is the caller’s responsibility to check this (using el_get() ) to determine if editing should be enabled or not.

EL_GETCFN , int (*f)(EditLine *, char *c)

Define the character reading function as f, which is to return the number of characters read and store them in c. This function is called internally by el_gets() and el_getc(). The builtin function can be set or restored with the special function name “EL_BUILTIN_GETCFN”.

EL_CLIENTDATA , void *data

Register data to be associated with this EditLine structure. It can be retrieved with the corresponding el_get() call.

EL_SETFP , int fd, Fa FILE *fp

Set the current editline file pointer for “input” fd = 0 , “output” fd = 1 , or “error” fd = 2 from fp.

el_get()

Get editline parameters. op determines which parameter to retrieve into result. Returns 0 if successful, -1 otherwise.

The following values for op are supported, along with actual type of result :

EL_PROMPT , char *(*f)(EditLine *): Return a pointer to the function that displays the prompt.
EL_RPROMPT , char *(*f)(EditLine *): Return a pointer to the function that displays the rightside prompt.
EL_EDITOR , const char *: Return the name of the editor, which will be one of “emacs” or “vi”.
EL_GETTC , const char *name, Fa void *value: Return non-zero if name is a valid termcap(5) capability and set value to the current value of that capability.
EL_SIGNAL , int *: Return non-zero if editline has installed private signal handlers (see el_get() above).
EL_EDITMODE , int *: Return non-zero if editing is enabled.
EL_GETCFN , int (**f)(EditLine *, char *): Return a pointer to the function that read characters, which is equal to “EL_BUILTIN_GETCFN” in the case of the default builtin function.
EL_CLIENTDATA , void **data: Retrieve data previously registered with the corresponding el_set() call.
EL_UNBUFFERED , int: Sets or clears unbuffered mode. In this mode, el_gets() will return immediately after processing a single character.
EL_PREP_TERM , int: Sets or clears terminal editing mode.
EL_GETFP , int fd", Fa FILE **fp: Return in fp the current editline file pointer for “input” fd = 0 , “output” fd = 1 , or “error” fd = 2 .

el_source()

Initialise editline by reading the contents of file. el_parse() is called for each line in file. If file is NULL , try $PWD/.editrc then $HOME/.editrc. Refer to editrc(5) for details on the format of file.

el_resize()

Must be called if the terminal size changes. If EL_SIGNAL has been set with el_set(), then this is done automatically. Otherwise, it’s the responsibility of the application to call el_resize() on the appropriate occasions.

el_line()

Return the editing information for the current line in a LineInfo structure, which is defined as follows:

typedef struct lineinfo {

const char *buffer; /* address of buffer */

const char *cursor; /* address of cursor */

const char *lastchar; /* address of last character */
} LineInfo;

buffer is not NUL terminated. This function may be called after el_gets() to obtain the LineInfo structure pertaining to line returned by that function, and from within user defined functions added with EL_ADDFN .

el_insertstr()

Insert str into the line at the cursor. Returns -1 if str is empty or won’t fit, and 0 otherwise.

el_deletestr()

Delete count characters before the cursor.

HISTORY LIST FUNCTIONS

The history functions use a common data structure, History, which is created by history_init() and freed by history_end().

The following functions are available:

history_init()

Initialise the history list, and return a data structure to be used by all other history list functions.

history_end()

Clean up and finish with h, assumed to have been created with history_init().

history()

Perform operation op on the history list, with optional arguments as needed by the operation. ev is changed accordingly to operation. The following values for op are supported, along with the required argument list:

H_SETSIZE , int size: Set size of history to size elements.
H_GETSIZE: Get number of events currently in history.
H_END: Cleans up and finishes with h, assumed to be created with history_init().
H_CLEAR: Clear the history.
H_FUNC , void *ptr, history_gfun_t first, history_gfun_t next, history_gfun_t last, history_gfun_t prev, history_gfun_t curr, history_sfun_t set, history_vfun_t clear, history_efun_t enter, history_efun_t add: Define functions to perform various history operations. ptr is the argument given to a function when it’s invoked.
H_FIRST: Return the first element in the history.
H_LAST: Return the last element in the history.
H_PREV: Return the previous element in the history.
H_NEXT: Return the next element in the history.
H_CURR: Return the current element in the history.
H_SET: Set the cursor to point to the requested element.
H_ADD , const char *str: Append str to the current element of the history, or perform the H_ENTER operation with argument str if there is no current element.
H_APPEND , const char *str: Append str to the last new element of the history.
H_ENTER , const char *str: Add str as a new element to the history, and, if necessary, removing the oldest entry to keep the list to the created size. If H_SETUNIQUE was has been called with a non-zero arguments, the element will not be entered into the history if its contents match the ones of the current history element. If the element is entered history() returns 1, if it is ignored as a duplicate returns 0. Finally history() returns -1 if an error occurred.
H_PREV_STR , const char *str: Return the closest previous event that starts with str.
H_NEXT_STR , const char *str: Return the closest next event that starts with str.
H_PREV_EVENT , int e: Return the previous event numbered e.
H_NEXT_EVENT , int e: Return the next event numbered e.
H_LOAD , const char *file: Load the history list stored in file.
H_SAVE , const char *file: Save the history list to file.
H_SETUNIQUE , int unique: Set flag that adjacent identical event strings should not be entered into the history.
H_GETUNIQUE: Retrieve the current setting if adjacent identical elements should be entered into the history.
H_DEL , int e: Delete the event numbered e. This function is only provided for readline(3) compatibility. The caller is responsible for free’ing the string in the returned HistEvent.

history() returns Gt]= 0 if the operation op succeeds. Otherwise, -1 is returned and ev is updated to contain more details about the error.

TOKENIZATION FUNCTIONS

The tokenization functions use a common data structure, Tokenizer, which is created by tok_init() and freed by tok_end().

The following functions are available:

tok_init()

Initialise the tokenizer, and return a data structure to be used by all other tokenizer functions. IFS contains the Input Field Separators, which defaults to <space> , <tab> , and <newline> if NULL .

tok_end()

Clean up and finish with t, assumed to have been created with tok_init().

tok_reset()

Reset the tokenizer state. Use after a line has been successfully tokenized by tok_line() or tok_str() and before a new line is to be tokenized.

tok_line()

Tokenize li, If successful, modify: argv to contain the words, argc to contain the number of words, cursorc (if not NULL ) to contain the index of the word containing the cursor, and cursoro (if not NULL ) to contain the offset within argv[cursorc] of the cursor.

Returns 0 if successful, -1 for an internal error, 1 for an unmatched single quote, 2 for an unmatched double quote, and 3 for a backslash quoted <newline .> A positive exit code indicates that another line should be read and tokenization attempted again.

tok_str()

A simpler form of tok_line(; ) str is a NUL terminated string to tokenize.

HISTORY

The editline library first appeared in Bx 4.4 . CC_REDISPLAY appeared in Nx 1.3 . CC_REFRESH_BEEP , EL_EDITMODE and the readline emulation appeared in Nx 1.4 . EL_RPROMPT appeared in Nx 1.5 .

AUTHORS

The editline library was written by Christos Zoulas. Luke Mewburn wrote this manual and implemented CC_REDISPLAY , CC_REFRESH_BEEP , EL_EDITMODE , and EL_RPROMPT . Jaromir Dolecek implemented the readline emulation.

BUGS

At this time, it is the responsibility of the caller to check the result of the EL_EDITMODE operation of el_get() (after an el_source() or el_parse() ) to determine if editline should be used for further input. I.e., EL_EDITMODE is purely an indication of the result of the most recent editrc(5) edit command.

el_getc (3) Linux Manual Page

NAME

LIBRARY

SYNOPSIS

DESCRIPTION

LINE EDITING FUNCTIONS

HISTORY LIST FUNCTIONS

TOKENIZATION FUNCTIONS

SEE ALSO

HISTORY

AUTHORS

BUGS

Index

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