curs_inopts 3x 2023-11-25 ncurses 6.4 Library calls

curs_inopts(3x)                  Library calls                 curs_inopts(3x)


       cbreak,  echo, halfdelay, intrflush, is_cbreak, is_echo, is_nl, is_raw,
       keypad, meta, nl, nocbreak, nodelay, noecho,  nonl,  noqiflush,  noraw,
       notimeout,  qiflush,  raw,  timeout,  wtimeout, typeahead - get and set
       curses terminal input options


       #include <curses.h>

       int cbreak(void);
       int nocbreak(void);

       int echo(void);
       int noecho(void);

       int intrflush(WINDOW *win, bool bf);
       int keypad(WINDOW *win, bool bf);
       int meta(WINDOW *win, bool bf);
       int nodelay(WINDOW *win, bool bf);
       int notimeout(WINDOW *win, bool bf);

       int nl(void);
       int nonl(void);

       int raw(void);
       int noraw(void);

       void qiflush(void);
       void noqiflush(void);

       int halfdelay(int tenths);
       void timeout(int delay);
       void wtimeout(WINDOW *win, int delay);

       int typeahead(int fd);

       /* extensions */
       int is_cbreak(void);
       int is_echo(void);
       int is_nl(void);
       int is_raw(void);


       The ncurses library provides several functions which let an application
       change  the  way  input from the terminal is handled.  Some are global,
       applying to all windows.  Others  apply  only  to  a  specific  window.
       Window-specific  settings  are  not  automatically  applied  to  new or
       derived windows.  An application must apply these to  each  window,  if
       the same behavior is needed.


       Normally,  the  tty  driver buffers typed characters until a newline or
       carriage return is typed.  The cbreak routine disables  line  buffering
       and   erase/kill   character-processing  (interrupt  and  flow  control
       characters  are  unaffected),  making  characters  typed  by  the  user
       immediately available to the program.  The nocbreak routine returns the
       terminal to normal (cooked) mode.

       Initially the terminal may or may not be in cbreak mode, as the mode is
       inherited;   therefore,  a  program  should  call  cbreak  or  nocbreak
       explicitly.  Most interactive programs  using  curses  set  the  cbreak
       mode.   Note  that  cbreak  overrides  raw.   [See curs_getch(3x) for a
       discussion of how these routines interact with echo and noecho.]


       The echo and noecho routines control whether characters  typed  by  the
       user  are  echoed  by  getch(3x) as they are typed.  Echoing by the tty
       driver is always disabled, but initially getch  is  in  echo  mode,  so
       characters  typed  are  echoed.   Authors  of most interactive programs
       prefer to do their own echoing in a controlled area of the  screen,  or
       not  to  echo  at all, so they disable echoing by calling noecho.  [See
       curs_getch(3x) for a discussion of how  these  routines  interact  with
       cbreak and nocbreak.]


       The  halfdelay routine is used for half-delay mode, which is similar to
       cbreak mode in that  characters  typed  by  the  user  are  immediately
       available to the program.  However, after blocking for tenths tenths of
       seconds, ERR is returned if nothing  has  been  typed.   The  value  of
       tenths must be a number between 1 and 255.  Use nocbreak to leave half-
       delay mode.


       If the intrflush option is enabled (bf is TRUE), and an  interrupt  key
       is  pressed on the keyboard (interrupt, break, quit), all output in the
       tty driver queue will be flushed, giving the effect of faster  response
       to  the interrupt, but causing curses to have the wrong idea of what is
       on the screen.  Disabling the option (bf is FALSE) prevents the  flush.
       The  default  for the option is inherited from the tty driver settings.
       The window argument is ignored.


       The keypad option enables  the  keypad  of  the  user's  terminal.   If
       enabled  (bf  is  TRUE),  the user can press a function key (such as an
       arrow key) and wgetch(3x)  returns  a  single  value  representing  the
       function  key,  as in KEY_LEFT.  If disabled (bf is FALSE), curses does
       not treat function keys specially and the program has to interpret  the
       escape  sequences  itself.  If the keypad in the terminal can be turned
       on (made to transmit) and off (made to work locally), turning  on  this
       option  causes  the  terminal keypad to be turned on when wgetch(3x) is
       called.  The default value for keypad is FALSE.


       Initially, whether the terminal returns 7  or  8  significant  bits  on
       input  depends  on the control mode of the tty driver [see termios(3)].
       To force 8 bits  to  be  returned,  invoke  meta(win,  TRUE);  this  is
       equivalent,  under  POSIX, to setting the CS8 flag on the terminal.  To
       force  7  bits  to  be  returned,  invoke  meta(win,  FALSE);  this  is
       equivalent,  under POSIX, to setting the CS7 flag on the terminal.  The
       window argument, win, is always ignored.  If the terminfo  capabilities
       smm  (meta_on)  and rmm (meta_off) are defined for the terminal, smm is
       sent to the terminal when meta(win, TRUE) is called  and  rmm  is  sent
       when meta(win, FALSE) is called.


       The  nl and nonl routines control whether the underlying display device
       translates the return key into newline on input.


       The nodelay option causes getch to be a non-blocking call.  If no input
       is  ready,  getch  returns ERR.  If disabled (bf is FALSE), getch waits
       until a key is pressed.


       When interpreting an escape sequence, wgetch(3x)  sets  a  timer  while
       waiting  for  the  next  character.  If notimeout(win, TRUE) is called,
       then wgetch does not set a timer.  The purpose of  the  timeout  is  to
       differentiate  between sequences received from a function key and those
       typed by a user.


       The raw and noraw routines place the terminal into or out of raw  mode.
       Raw  mode  is  similar  to  cbreak  mode,  in that characters typed are
       immediately passed through to the user program.   The  differences  are
       that  in  raw  mode,  the  interrupt,  quit,  suspend, and flow control
       characters are all passed through uninterpreted, instead of  generating
       a  signal.   The behavior of the BREAK key depends on other bits in the
       tty driver that are not set by curses.


       When the noqiflush routine is used, normal flush of  input  and  output
       queues  associated  with the INTR, QUIT and SUSP characters will not be
       done [see termios(3)].  When qiflush is  called,  the  queues  will  be
       flushed  when  these control characters are read.  You may want to call
       noqiflush in a signal handler if you want output to continue as  though
       the interrupt had not occurred, after the handler exits.


       The timeout and wtimeout routines set blocking or non-blocking read for
       a given window.  If delay is negative, blocking  read  is  used  (i.e.,
       waits  indefinitely  for  input).   If delay is zero, then non-blocking
       read is used (i.e., read returns ERR if no input is waiting).  If delay
       is  positive,  then read blocks for delay milliseconds, and returns ERR
       if there is still no input.  Hence, these  routines  provide  the  same
       functionality  as nodelay, plus the additional capability of being able
       to block for only delay milliseconds (where delay is positive).


       The curses library does "line-breakout  optimization"  by  looking  for
       typeahead  periodically  while updating the screen.  If input is found,
       and it is coming from a tty, the  current  update  is  postponed  until
       refresh(3x)  or  doupdate is called again.  This allows faster response
       to commands typed in advance.  Normally, the input FILE pointer  passed
       to newterm, or stdin in the case that initscr was used, will be used to
       do this typeahead checking.  The typeahead routine specifies  that  the
       file descriptor fd is to be used to check for typeahead instead.  If fd
       is -1, then no typeahead checking is done.


       All routines that return an integer return  ERR  upon  failure  and  OK
       (SVr4 specifies only "an integer value other than ERR") upon successful
       completion,  unless  otherwise   noted   in   the   preceding   routine

       X/Open  does  not define any error conditions.  In this implementation,
       functions with a window parameter will return an error if it  is  null.
       Any  function  will  also  return  an  error  if  the  terminal was not
       initialized.  Also,

               returns an error if its parameter is outside the range 1..255.


       Note that echo, noecho, halfdelay, intrflush, meta, nl, nonl,  nodelay,
       notimeout, noqiflush, qiflush, timeout, and wtimeout may be macros.

       The  noraw  and  nocbreak calls follow historical practice in that they
       attempt to restore to normal ("cooked") mode from raw and cbreak  modes
       respectively.   Mixing raw/noraw and cbreak/nocbreak calls leads to tty
       driver control states that are hard to predict or understand; it is not


       This implementation provides four functions which may be used to detect
       if the corresponding flags were set or reset:

       Query       Set      Reset
       is_cbreak   cbreak   nocbreak
       is_echo     echo     noecho
       is_nl       nl       nonl
       is_raw      raw      noraw

       In each case, the function returns

       1    if the flag is set,

       0    if the flag is reset, or

       -1   if the curses library was not initialized.

       These routines are specific to ncurses.  They  were  not  supported  on
       Version 7, BSD or System V implementations.  It is recommended that any
       code   depending   on   ncurses   extensions   be   conditioned   using


       Except  as  noted  in  the  section  on extensions, these functions are
       described in the XSI Curses standard, Issue 4.

       The ncurses library obeys the XPG4 standard and the historical practice
       of  the  AT&T  curses  implementations, in that the echo bit is cleared
       when curses initializes the terminal state.  BSD curses  differed  from
       this  slightly;  it left the echo bit on at initialization, but the BSD
       raw call turned it off as a side-effect.   For  best  portability,  set
       echo  or  noecho  explicitly  just  after  initialization, even if your
       program remains in cooked mode.

       The XSI Curses standard is ambiguous on the  question  of  whether  raw
       should  disable  the  CRLF translations controlled by nl and nonl.  BSD
       curses did turn off these translations; AT&T curses (at least  as  late
       as  SVr1)  did not.  We chose to do so, on the theory that a programmer
       requesting raw input wants a clean  (ideally  8-bit  clean)  connection
       that the operating system will not alter.

       When keypad is first enabled, ncurses loads the key-definitions for the
       current terminal description.  If  the  terminal  description  includes
       extended  string  capabilities,  e.g., from using the -x option of tic,
       then ncurses also defines keys for the capabilities whose  names  begin
       with  "k".   The corresponding keycodes are generated and (depending on
       previous loads of terminal descriptions) may differ from one  execution
       of a program to the next.  The generated keycodes are recognized by the
       keyname function (which will then return  a  name  beginning  with  "k"
       denoting  the terminfo capability name rather than "K", used for curses
       key-names).  On the other hand, an application can  use  define_key  to
       establish  a  specific  keycode  for  a  given  string.   This makes it
       possible for an application  to  check  for  an  extended  capability's
       presence  with  tigetstr,  and  reassign  the  keycode to match its own

       Low-level applications can use tigetstr to obtain the definition of any
       particular  string capability.  Higher-level applications which use the
       curses wgetch and similar functions to return keycodes  rely  upon  the
       order in which the strings are loaded.  If more than one key definition
       has the same string value, then wgetch can  return  only  one  keycode.
       Most curses implementations (including ncurses) load key definitions in
       the order defined by the array of string capability  names.   The  last
       key  to  be  loaded  determines the keycode which will be returned.  In
       ncurses, you may also have extended  capabilities  interpreted  as  key
       definitions.   These  are  loaded  after  the predefined keys, and if a
       capability's value is the same as a previously-loaded  key  definition,
       the later definition is the one used.


       curses(3x),     curs_getch(3x),     curs_initscr(3x),    curs_util(3x),
       define_key(3x), termios(3)

ncurses 6.4                       2023-11-25                   curs_inopts(3x)