EDITLINE(3)

NAME
editline, el_init, el_end, el_reset, el_gets, el_getc, el_push, el_parse, el_set, el_source, el_resize, el_line, el_insertstr, el_deletestr, history_init, history_end, history - line editor and history functions

LIBRARY
libedit

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, char *argv[]);
int
el_set(EditLine *e, int op, ...);
int
el_get(EditLine *e, int op, void *result);
int
el_source(EditLine *e, const char *file);
void
el_resize(EditLine *e);
const LineInfo *
el_line(EditLine *e);
int
el_insertstr(EditLine *e, 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, ...);

DESCRIPTION
The editline 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.

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_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_get()
    Get editline 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_EDITOR, const char *
        Return the name of the editor, which will be one of “emacs” or “vi”.

    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_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;

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.

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 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.

SEE ALSO
editrc(5), sh(1), signal(3), termcap(3)

HISTORY
The editline library first appeared in 4.4BSD.

AUTHORS
The editline library was written by Christos Zoulas, and this manual was written by Luke Mewburn.

BUGS
The tokenization functions are not publically defined in <histedit.h>

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.