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

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

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() 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 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() for more information.

el_parse

Parses the argv array (which is argc elements in size) to execute builtin commands. If the command is prefixed with then el_parse will only execute the command if 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 didn't match, or 1 if the command returned an error. Refer to editrc() for more information.

el_set

Set 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_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 or

EL_SIGNAL , int flag

If flag is non-zero, 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 , Xo

const char * , ... , NULL Perform the bind builtin command. Refer to editrc() for more information.

EL_ECHOTC , Xo

const char * , ... , NULL Perform the echotc builtin command. Refer to editrc() for more information.

EL_SETTC , Xo

const char * , ... , NULL Perform the settc builtin command. Refer to editrc() for more information.

EL_SETTY , Xo

const char * , ... , NULL Perform the setty builtin command. Refer to editrc() for more information.

EL_TELLTC , Xo

const char * , ... , NULL Perform the telltc builtin command. Refer to editrc() for more information.

EL_ADDFN , Xo

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 , Xo

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_get

Get parameters. op determines which parameter to retrieve into result . 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 or

EL_SIGNAL , int *

Return non-zero if 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_source

Initialise 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() 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;

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 num characters before the cursor.

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 , Xo

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 create an element with

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.

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 .

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

The library first appeared in CC_REDISPLAY appeared in CC_REFRESH_BEEP , EL_EDITMODE and the readline emulation appeared in EL_RPROMPT appeared in

The 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.

The tokenization functions are not publicly defined in [Lt]histedit.h[Gt] .

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 should be used for further input. I.e., EL_EDITMODE is purely an indication of the result of the most recent editrc() edit command.