editline(3) Library Functions Manual editline(3)

NAME

 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 - 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);
 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

 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
 libtermcap library). Programs should be linked with -ledit ltermcap .
 The editline library respects the LC_CTYPE locale set by the
 application program and never uses setlocale(3)  to change the locale.

LINE EDITING FUNCTIONS

 The line editing functions use a common data structure, EditLine, which
 is created by el_init() or el_init_fd() and freed by el_end().
 The wide-character functions behave the same way as their narrow
 counterparts.
 The following functions are available:
 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) .
 el_end()
 Clean up and finish with e, assumed to have been created with
 el_init() or el_init_fd().
 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. If
 an error occurred, count is set to -1 and errno contains the
 error code that caused it. The return value may not remain
 valid across calls to el_gets() and must be copied if the data
 is to be retained.
 el_wgetc()
 Read a wide character from the tty, respecting the current
 locale, or from the input queue described in editline(3) 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 Er 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.
 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 Er 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.
 el_wpush()
 Push the wide character string wcs back onto the input queue
 described in editline(3). 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.
 el_push()
 Use the current locale to convert the multibyte string mbs to a
 wide character string, and pass the result to el_wpush().
 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.
 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 *), Fa 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 *), Fa 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 *, Fa ..., Dv NULL
 Perform the bind builtin command. Refer to editrc(5)  for
 more information.
 EL_ECHOTC , const char *, Fa ..., Dv NULL
 Perform the echotc builtin command. Refer to editrc(5) 
 for more information.
 EL_SETTC , const char *, Fa ..., Dv NULL
 Perform the settc builtin command. Refer to editrc(5) 
 for more information.
 EL_SETTY , const char *, Fa ..., Dv NULL
 Perform the setty builtin command. Refer to editrc(5) 
 for more information.
 EL_TELLTC , const char *, Fa ..., Dv NULL
 Perform the telltc builtin command. Refer to editrc(5) 
 for more information.
 EL_ADDFN , const char *name, Fa const char *help,
 Fa "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, ...),
 Fa "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_UNBUFFERED , int flag
 If flag is zero, unbuffered mode is disabled (the
 default). In unbuffered mode, el_gets() will return
 immediately after processing a single character.
 EL_SAFEREAD , int flag
 If the flag argument is non-zero, then 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. This is disabled
 by default, and desirable only when editline is used in
 shell-like applications.
 EL_GETCFN , el_rfunc_t f
 Whenever reading a character, use the function -ragged
 -offset indent -compact
 int
 Fo f EditLine *e wchar_t *wc Fc which stores the character in wc
 and returns 1 on success, 0 on end of file, or -1 on I/O or
 encoding errors. 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. 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 *), Fa 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 *), Fa 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, Fa 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 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", Fa FILE **fp
 Set fp to the current editline file pointer for
 ``input'' fd = 0 , ``output'' fd = 1 , or ``error'' fd
 = 2 .
 el_source()
 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 is not set $HOME/.editrc. Refer to editrc(5)  for
 details on the format of file. el_source() returns 0 on success
 and -1 on error.
 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_cursor()
 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()
 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()
 Initialize the history list, and return a data structure to be
 used by all other history list functions, or NULL on failure.
 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, Fa history_gfun_t first,
 Fa "history_gfun_t next" , Fa "history_gfun_t last" , Fa
 "history_gfun_t prev" , Fa "history_gfun_t curr" , Fa
 "history_sfun_t set" , Fa "history_vfun_t clear" , Fa
 "history_efun_t enter" , Fa "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. It is newer
 than the current one.
 H_NEXT Return the next element in the history. It is older than
 the current one.
 H_CURR Return the current element in the history.
 H_SET , int position
 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 has been called with a
 non-zero argument, 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_SAVE_FP , FILE *fp
 Save the history list to the opened
 FILE
 pointer fp.
 H_NSAVE_FP , size_t n, Fa FILE *fp
 Save the last
 n
 history entries to the opened
 FILE
 pointer fp.
 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 compatibility. The caller is
 responsible for free'ing the string in the returned
 HistEvent.
 history(); returns >= 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()
 Initialize 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.

SEE ALSO

 editline(3)

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

 -nosplit 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.

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.
 August 15, 2021 editline(3)