EDITLINE(3edit)

✨ NAME ✨

okay so bestie, this is editline(3edit), and it's literally the whole squad of line editor, history and tokenization functions. We're talking: editline, el_init, el_init_fd, el_end, el_reset, el_gets, el_wgets, el_getc, el_wgetc, el_push, el_wpush, el_parse, el_wparse, el_set, el_wset, el_get, el_wget, el_source, el_resize, el_cursor, el_line, el_wline, el_insertstr, el_winsertstr, el_deletestr, el_wdeletestr, history_init, history_winit, history_end, history_wend, history, history_w, tok_init, tok_winit, tok_end, tok_wend, tok_reset, tok_wreset, tok_line, tok_wline, tok_str, tok_wstr. All of them = line editor, history and tokenization functions, and yes, that's the whole vibe. 💅

📚 LIBRARY 💖

Command Line Editor Library (libedit, -ledit). Slay.

🛠️ SYNOPSIS 🧚

#include <histedit.h>

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

EditLine *
el_init_fd(const char *prog, FILE *fin, FILE *fout, FILE *ferr,
    int fdin, int fdout, int fderr);

void
el_end(EditLine *e);

void
el_reset(EditLine *e);

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

const wchar_t *
el_wgets(EditLine *e, int *count);

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

int
el_wgetc(EditLine *e, wchar_t *wc);

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

void
el_wpush(EditLine *e, const wchar_t *wcs);

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

int
el_wparse(EditLine *e, int argc, const wchar_t *argv[]);

int
el_set(EditLine *e, int op, ...);

int
el_wset(EditLine *e, int op, ...);

int
el_get(EditLine *e, int op, ...);

int
el_wget(EditLine *e, int op, ...);

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

void
el_resize(EditLine *e);

int
el_cursor(EditLine *e, int count);

const LineInfo *
el_line(EditLine *e);

const LineInfoW *
el_wline(EditLine *e);

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

int
el_winsertstr(EditLine *e, const wchar_t *str);

void
el_deletestr(EditLine *e, int count);

void
el_wdeletestr(EditLine *e, int count);

History *
history_init(void);

HistoryW *
history_winit(void);

void
history_end(History *h);

void
history_wend(HistoryW *h);

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

int
history_w(HistoryW *h, HistEventW *ev, int op, ...);

Tokenizer *
tok_init(const char *IFS);

TokenizerW *
tok_winit(const wchar_t *IFS);

void
tok_end(Tokenizer *t);

void
tok_wend(TokenizerW *t);

void
tok_reset(Tokenizer *t);

void
tok_wreset(TokenizerW *t);

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

int
tok_wline(TokenizerW *t, const LineInfoW *li, int *argc,
    const wchar_t **argv[], int *cursorc, int *cursoro);

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

int
tok_wstr(TokenizerW *t, const wchar_t *str, int *argc,
    const wchar_t **argv[]);

🌸 DESCRIPTION 🌸

so editline is out here providing generic line editing, history and tokenization functions, just like the ones you'd find in sh(1).

These functions live in the libedit library (which needs the libtermcap library, no cap). Link your programs with -ledit -ltermcap and you're good.

Also, editline respects the LC_CTYPE locale set by the application program and never uses setlocale(3) to change the locale. periodt.

💅 LINE EDITING FUNCTIONS 💅

okay so the line editing functions all share one common data structure, EditLine, and it's created by el_init() or el_init_fd() and freed by el_end(). iconic.

The wide-character functions behave the same way as their narrow counterparts. no notes.

The following functions are available, bestie:

el_init()

Initialize the line editor, and return a data structure to be used by all other line editing functions, or NULL on failure. 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_init_fd()

Like el_init() but allows specifying file descriptors for the stdio(3) corresponding streams, in case those were created with funopen(3). slay.

el_end()

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

el_reset()

Reset the tty and the parser. This should be called after an error which may have upset the tty's state. it's giving damage control.

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. If an error occurred, count is set to -1 and errno contains the error code that caused it. Important: the return value may not remain valid across calls to el_gets() and must be copied if the data is to be retained. no cap.

el_wgetc()

Read a wide character from the tty, respecting the current locale, or from the input queue described in editline(7) if that is not empty, and store it in wc. If an invalid or incomplete character is found, it is discarded, errno is set to EILSEQ, and the next character is read and stored in wc. Returns 1 if a valid character was read, 0 on end of file, or -1 on read(2) failure. In the latter case, errno is set to indicate the error. messy but okay.

el_getc()

Read a wide character as described for el_wgetc() and return 0 on end of file or -1 on failure. If the wide character can be represented as a single-byte character, convert it with wctob(3), store the result in ch, and return 1; otherwise, set errno to ERANGE and return -1. In the C or POSIX locale, this simply reads a byte, but for any other locale, including UTF-8, this is rarely useful. iykyk.

el_wpush()

Push the wide character string wcs back onto the input queue described in editline(7). If the queue overflows, for example due to a recursive macro, or if an error occurs, for example because wcs is NULL or memory allocation fails, the function beeps at the user, but does not report the problem to the caller. it's giving silent treatment.

el_push()

Use the current locale to convert the multibyte string mbs to a wide character string, and pass the result to el_wpush(). teamwork.

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. Returns 0 on success, -1 on failure. let's go.

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_PROMPT_ESC, char *(*f)(EditLine *), char c — Same as EL_PROMPT, but the c argument indicates the start/stop literal prompt character.

If a start/stop literal character is found in the prompt, the character itself is not printed, but characters after it are printed directly to the terminal without affecting the state of the current line. A subsequent second start/stop literal character ends this behavior. This is typically used to embed literal escape sequences that change the color/style of the terminal in the prompt. Note that the literal escape character cannot be the last character in the prompt, as the escape sequence is attached to the next character in the prompt. 0 unsets it.

• 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_RPROMPT_ESC, char *(*f)(EditLine *), char c — Define the right prompt printing function but with a literal escape character.
• 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 the display ✨
• CC_REFRESH_BEEP — refresh the display and beep 🔔
• CC_CURSOR — the cursor moved, so update and do a CC_REFRESH 💫
• CC_REDISPLAY — redisplay the entire input line. This one's lowkey a lifesaver if a key binding outputs extra information 🫶
• CC_ERROR — an error happened: beep, and flush the tty 😭
• CC_FATAL — fatal error, reset the tty to a known state 💀
• EL_HIST, History *(*func)(History *, int op, ...), const char *ptr — says which history function to use, which is usually history(). And ptr should be the value that history_init() handed back to you 🎀
• EL_EDITMODE, int flag — if flag is non-zero, editing is enabled (that's the default). But heads up bestie: this is literally just an indication, it does not affect how editline operates. At this time, it is the caller's responsibility to check this (using el_get()) to decide whether editing should be enabled or not 👑
• EL_UNBUFFERED, int flag — if flag is zero, unbuffered mode is disabled (the default). In unbuffered mode, el_gets() returns immediately after processing a single character ⚡
• EL_SAFEREAD, int flag — if flag is non-zero, editline attempts to recover from read errors, ignoring the first interrupted error and trying to reset the input file descriptor to reset non-blocking I/O. It's disabled by default, and it's only desirable when editline is used in shell-like applications 🐚
• EL_GETCFN, el_rfunc_t f — whenever a character is being read, use this function:

int f(EditLine *e, wchar_t *wc)

which stores the character in wc and returns 1 on success, 0 on end of file, or -1 on I/O or encoding errors 🦋 The functions internally using it include el_wgets(), el_wgetc(), el_gets(), and el_getc(). Initially a builtin function is installed, and replacing it is discouraged because writing such a function is very error prone 😭 The builtin function can be restored at any time by passing the special value EL_BUILTIN_GETCFN instead of a function pointer 💅

• EL_CLIENTDATA, void *data — register data to be associated with this EditLine structure. You can get it back with the corresponding el_get() call 🌸
• EL_SETFP, int fd, FILE *fp — set the current editline file pointer for "input" fd = 0, "output" fd = 1, or "error" fd = 2 from fp 🎀
• EL_GETENV, char * (*funcp)(const char *) — makes the function editline uses to obtain the value of an environment variable become the one you pass as funcp: a pointer to a function that takes a const char * as its parameter and returns char *. The default is getenv(3) 🌈

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el_get() — the getter era 💖

Get editline parameters. op decides which parameter gets retrieved into result. Returns 0 if it went well, -1 otherwise.

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

• EL_PROMPT, char *(*f)(EditLine *), char *c — set f to a pointer to the function that displays the prompt. If c is not NULL, set it to the start/stop literal prompt character ✨
• EL_RPROMPT, char *(*f)(EditLine *), char *c — set f to a pointer to the function that displays the prompt. If c is not NULL, set it to the start/stop literal prompt character ✨
• EL_EDITOR, const char **n — set the name of the editor in n, which will be one of "emacs" or "vi" 💅
• EL_GETTC, const char *name, void *value — if name is a valid termcap(5) capability, set value to the current value of that capability 🧚
• EL_SIGNAL, int *s — set s to non-zero if editline has installed private signal handlers (see el_get() above) 📡
• EL_EDITMODE, int *c — set c to non-zero if editing is enabled 👑
• EL_GETCFN, el_rfunc_t *f — set f to a pointer to the function that reads characters, or to EL_BUILTIN_GETCFN if the builtin function is the one in use 🔍
• EL_CLIENTDATA, void **data — set data to the previously registered client data set by an el_set() call 🎁
• EL_UNBUFFERED, int *c — set c to non-zero if unbuffered mode is enabled ⚡
• EL_SAFEREAD, int *c — set c to non-zero if safe read is set 🛡️
• EL_GETFP, int fd, FILE **fp — set fp to the current editline file pointer for "input" fd = 0, "output" fd = 1, or "error" fd = 2 📂
• EL_WORDCHARS, Char *wordchars — define the list of characters that can be part of a word, in addition to alphanumeric characters. This list is *?_-.[]~= for emacs mode and _ for vi mode. Resetting the editor binding to either emacs or vi also resets the wordchars to their default value 🔤
• EL_GETENV, char * (**funcp)(const char *) — return, via the pointer to a pointer to a function, funcp, the function that editline is using to obtain the values of environment variables 🌍

---

el_source() — reading the vibes off a file 📜

Initialize editline by reading the contents of file. el_parse() is called for each line in file. If file is NULL, try $EDITRC and if that's not set, $HOME/.editrc. Peep editrc(5) for the details on the format of file. el_source() returns 0 on success and -1 on error 🫶

el_resize() — for when the terminal changes shape 📐

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

el_cursor() — scoot scoot 🛴

Move the cursor to the right (if positive) or to the left (if negative) count characters. Returns the resulting offset of the cursor from the beginning of the line 📏

el_line() — all the tea about the current 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 the line returned by that function, and from within user defined functions added with EL_ADDFN 💫

el_insertstr() — slide it in 💌

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

el_deletestr() — bye bye, backspace energy 🗑️

Delete count characters before the cursor.

📜 HISTORY LIST FUNCTIONS 📜

So all the history functions share one lil data structure called History, and you get it from history_init() and yeet it away with history_end(). That's the whole vibe. 🫶

Here's every function you've got, bestie:

• history_init() — Boots up the history list and hands you back a data structure that every other history function will use. If it flops, you get NULL. 😭
• history_end() — Wraps everything up and says bye-bye to h, which we're assuming came from history_init().
• history() — Does the operation op on the history list, with whatever optional arguments that operation needs. And ev gets updated to match whatever operation you did. Here's all the stuff op can be, plus the argument list each one demands:
  • H_SETSIZE, int size — Sets the size of the history to size elements.
  • H_GETSIZE — Gets the number of events currently in history.
  • H_END — Cleans up and finishes with h, which we assume came from history_init().
  • H_CLEAR — Clears the history. Poof. Gone. ✨
  • 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 — Defines the functions that carry out the various history operations. ptr is the argument handed to a function when it gets invoked.
  • H_FIRST — Returns the first element in the history.
  • H_LAST — Returns the last element in the history.
  • H_PREV — Returns the previous element in the history. It's newer than the current one.
  • H_NEXT — Returns the next element in the history. It's older than the current one.
  • H_CURR — Returns the current element in the history.
  • H_SET, int position — Puts the cursor on the element you asked for.
  • H_ADD, const char *str — Appends str onto the current element of the history, or if there's no current element it just does the H_ENTER operation with str as the argument instead.
  • H_APPEND, const char *str — Appends str to the last new element of the history.
  • H_ENTER, const char *str — Adds str as a brand new element to the history and, if it has to, removes the oldest entry so the list stays at the size you created it with. Now listen: if H_SETUNIQUE was called with a non-zero argument, the element will not be entered into the history if its contents match the current history element. If the element does get entered, history() returns 1; if it gets ignored as a duplicate, it returns 0. And finally, history() returns -1 if an error happened. 💀
  • H_PREV_STR, const char *str — Returns the closest previous event that starts with str.
  • H_NEXT_STR, const char *str — Returns the closest next event that starts with str.
  • H_PREV_EVENT, int e — Returns the previous event numbered e.
  • H_NEXT_EVENT, int e — Returns the next event numbered e.
  • H_LOAD, const char *file — Loads the history list stored in file.
  • H_SAVE, const char *file — Saves the history list to file.
  • H_SAVE_FP, FILE *fp — Saves the history list to the opened FILE pointer fp.
  • H_NSAVE_FP, size_t n, FILE *fp — Saves the last n history entries to the opened FILE pointer fp.
  • H_SETUNIQUE, int unique — Sets the flag so adjacent identical event strings don't get entered into the history.
  • H_GETUNIQUE — Gets the current setting for whether adjacent identical elements should be entered into the history.
  • H_DEL, int e — Deletes the event numbered e. Heads up: this one is only there for readline compatibility. The caller is the one responsible for free'ing the string in the returned HistEvent. 🙈

history() returns >= 0 if the operation op succeeds. Otherwise -1 comes back and ev gets updated with more details about the error.

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🔪 TOKENIZATION FUNCTIONS 🔪

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

Here's what you've got:

• tok_init() — Initializes the tokenizer and returns a data structure that all the other tokenizer functions will use. IFS holds the Input Field Separators, which defaults to ⟨space⟩, ⟨tab⟩, and ⟨newline⟩ if it's NULL.
• tok_end() — Cleans up and finishes with t, assumed to have been created with tok_init().
• tok_reset() — Resets the tokenizer state. Use this after a line has been successfully tokenized by tok_line() or tok_str() and before you tokenize a new line.
• tok_line() — Tokenizes li. If it works, it modifies: argv to contain the words, argc to contain the number of words, cursorc (if it's not NULL) to contain the index of the word containing the cursor, and cursoro (if it's 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 means you should read another line and try the tokenization again. 🔁

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

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👀 SEE ALSO 👀

sh(1), signal(3), termcap(3), editrc(5edit), termcap(5), editline(7edit)

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⏳ HISTORY (the other kind lol) ⏳

The editline library first appeared in 4.4BSD. CC_REDISPLAY appeared in NetBSD 1.3. CC_REFRESH_BEEP, EL_EDITMODE and the readline emulation appeared in NetBSD 1.4. EL_RPROMPT appeared in NetBSD 1.5. It's giving legacy. 👑

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👑 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. Johny Mattsson implemented wide-character support. Not one, not two, not three, but four icons. We stan. 💅

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🐛 BUGS 🐛

Okay so right now, it is the caller's responsibility to check the result of the EL_EDITMODE operation of el_get() (after an el_source() or el_parse()) to figure out whether editline should be used for further input. Like, EL_EDITMODE is purely an indication of the result of the most recent editrc(5) edit command. That's it. No cap. Don't @ me. 😭

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And that's a wrap on EDITLINE(3edit), bestie — this page came from the Debian crew and is dated December 16, 2025, so if it looks fresh, that's because it is. Go forth and edit lines. Slay. 💖✨🎀