## NAME

           ncurses - CRT screen handling and optimization package

## SYNOPSIS

           #include <curses.h>

## DESCRIPTION

           The  ncurses  library  routines  give the user a terminal-
           independent method of updating character screens with rea-
           sonable   optimization.    This  implementation  is  ``new
           curses'' (ncurses) and is  the  approved  replacement  for
           4.4BSD classic curses, which has been discontinued.

           The  ncurses  routines  emulate  the curses(3x) library of
           System V Release 4 UNIX, and the XPG4 curses standard (XSI
           curses)  but the ncurses library is freely redistributable
           in source form.  Differences from the SVr4 curses are sum-
           marized  under  the EXTENSIONS and BUGS sections below and
           described in detail in the EXTENSIONS and BUGS sections of
           individual man pages.

           A  program  using  these  routines must be linked with the
           -lncurses option, or (if it has been generated)  with  the
           debugging  library  -lncurses_g.   (Your system integrator
           may also have installed these libraries  under  the  names
           -lcurses and -lcurses_g.)  The ncurses_g library generates
           trace logs (in a file called 'trace' in the current direc-
           tory) that describe curses actions.

           The  ncurses  package supports: overall screen, window and
           pad manipulation; output to windows and pads; reading ter-
           minal  input;  control  over terminal and curses input and
           output options; environment query routines; color  manipu-
           lation; use of soft label keys; terminfo capabilities; and
           access to low-level terminal-manipulation routines.

           To initialize the routines, the routine initscr or newterm
           must  be called before any of the other routines that deal
           with windows and screens are  used.   The  routine  endwin
           must be called before exiting.  To get character-at-a-time
           input without echoing (most interactive,  screen  oriented
           programs  want  this),  the  following  sequence should be
           used:

                 initscr(); cbreak(); noecho();

           Most programs would additionally use the sequence:

                 nonl();
                 intrflush(stdscr, FALSE);
                 keypad(stdscr, TRUE);

           Before a curses program is run, the tab stops of the  ter-
           minal  should  be  set  and its initialization strings, if
           defined, must be output.  This can be  done  by  executing
           the tput init command after the shell environment variable
           TERM has been exported.  tset(1)  is  usually  responsible
           for doing this.  [See terminfo(5) for further details.]

           The  ncurses  library  permits manipulation of data struc-
           tures, called windows, which can be  thought  of  as  two-
           dimensional  arrays of characters representing all or part
           of a CRT screen.  A default window called stdscr, which is
           the  size of the terminal screen, is supplied.  Others may
           be created with newwin.

           Note that curses  does  not  handle  overlapping  windows,
           that's  done by the panel(3x) library. This means that you
           can either use stdscr or divide the screen into tiled win-
           dows  and  not  using  stdscr  at all. Mixing the two will
           result in unpredictable, and undesired, effects.

           Windows are referred to by variables declared as WINDOW *.
           These   data  structures  are  manipulated  with  routines
           described here and elsewhere in the ncurses manual  pages.
           Among  which  the  most basic routines are move and addch.
           More general versions of these routines are included  with
           names  beginning  with  w,  allowing the user to specify a
           window.  The routines not beginning with w affect stdscr.)

           After  using  routines  to manipulate a window, refresh is
           called, telling curses to make the user's CRT screen  look
           like  stdscr.   The characters in a window are actually of
           type chtype, (character and attribute data) so that  other
           information  about  the  character may also be stored with
           each character.

           Special windows  called  pads  may  also  be  manipulated.
           These are windows which are not constrained to the size of
           the screen and whose contents need not be completely  dis-
           played.  See curs_pad(3x) for more information.

           In  addition  to  drawing  characters on the screen, video
           attributes and colors may be supported, causing the  char-
           acters  to show up in such modes as underlined, in reverse
           video, or in color on terminals that support such  display
           enhancements.  Line drawing characters may be specified to
           be output.  On input, curses is  also  able  to  translate
           arrow  and  function  keys  that transmit escape sequences
           into single values.  The video  attributes,  line  drawing
           characters,   and  input  values  use  names,  defined  in
           <curses.h>, such as A_REVERSE, ACS_HLINE, and KEY_LEFT.

           If the environment variables LINES and COLUMNS are set, or
           if  the program is executing in a window environment, line
           and column information in the  environment  will  override
           information read by terminfo.  This would effect a program
           running in an AT&T 630 layer, for example, where the  size
           of a screen is changeable (see ENVIRONMENT).

           If  the environment variable TERMINFO is defined, any pro-
           gram using curses checks for a local  terminal  definition
           before  checking  in  the standard place.  For example, if
           TERM is set to att4424, then the compiled terminal defini-
           tion is found in

                 @DATADIR@/terminfo/a/att4424.

           (The a is copied from the first letter of att4424 to avoid
           creation of huge directories.)  However,  if  TERMINFO  is
           set to $HOME/myterms, curses first checks

                 $HOME/myterms/a/att4424,

           and if that fails, it then checks

                 @DATADIR@/terminfo/a/att4424.

           This  is useful for developing experimental definitions or
           when write permission in @DATADIR@/terminfo is not  avail-
           able.

           The  integer  variables  LINES  and  COLS  are  defined in
           <curses.h> and will be filled in by initscr with the  size
           of the screen.  The constants TRUE and FALSE have the val-
           ues 1 and 0, respectively.

           The curses routines also  define  the  WINDOW  *  variable
           curscr which is used for certain low-level operations like
           clearing and redrawing a screen containing  garbage.   The
           curscr can be used in only a few routines.

       Routine and Argument Names
           Many  curses routines have two or more versions.  The rou-
           tines prefixed with w require a window argument.  The rou-
           tines prefixed with p require a pad argument.  Those with-
           out a prefix generally use stdscr.

           The routines prefixed with mv require a y and x coordinate
           to  move to before performing the appropriate action.  The
           mv routines imply a call to move before the  call  to  the
           other  routine.  The coordinate y always refers to the row
           (of the window), and x always refers to the  column.   The
           upper left-hand corner is always (0,0), not (1,1).

           The routines prefixed with mvw take both a window argument
           and x and y coordinates.  The window  argument  is  always
           specified before the coordinates.

           In  each  case, win is the window affected, and pad is the
           pad affected; win and pad  are  always  pointers  to  type
           WINDOW.

           Option setting routines require a Boolean flag bf with the
           value TRUE or FALSE; bf is always of type bool.  The vari-
           ables  ch  and attrs below are always of type chtype.  The
           types WINDOW, SCREEN, bool,  and  chtype  are  defined  in
           <curses.h>.   The  type  TERMINAL  is defined in <term.h>.
           All other arguments are integers.

       Routine Name Index
           The following table lists each curses routine and the name
           of  the  manual  page  on which it is described.  Routines
           flagged with `*' are ncurses-specific,  not  described  by
           XPG4 or present in SVr4.

                   curses Routine Name     Manual Page Name
                   -------------------------------------------
                   COLOR_PAIR              curs_color(3x)
                   PAIR_NUMBER             curs_attr(3x)
                   _nc_tracebits           curs_trace(3x)*
                   _traceattr              curs_trace(3x)*
                   _traceattr2             curs_trace(3x)*
                   _tracechar              curs_trace(3x)*
                   _tracechtype            curs_trace(3x)*
                   _tracechtype2           curs_trace(3x)*
                   _tracedump              curs_trace(3x)*
                   _tracef                 curs_trace(3x)*
                   _tracemouse             curs_trace(3x)*
                   addch                   curs_addch(3x)
                   addchnstr               curs_addchstr(3x)
                   addchstr                curs_addchstr(3x)
                   addnstr                 curs_addstr(3x)
                   addstr                  curs_addstr(3x)
                   assume_default_colors   dft_fgbg(3x)*
                   attr_get                curs_attr(3x)
                   attr_off                curs_attr(3x)
                   attr_on                 curs_attr(3x)
                   attr_set                curs_attr(3x)
                   attroff                 curs_attr(3x)
                   attron                  curs_attr(3x)
                   attrset                 curs_attr(3x)
                   baudrate                curs_termattrs(3x)
                   beep                    curs_beep(3x)
                   bkgd                    curs_bkgd(3x)
                   bkgdset                 curs_bkgd(3x)
                   border                  curs_border(3x)
                   box                     curs_border(3x)
                   can_change_color        curs_color(3x)
                   cbreak                  curs_inopts(3x)
                   chgat                   curs_attr(3x)
                   clear                   curs_clear(3x)
                   clearok                 curs_outopts(3x)

                   clrtobot                curs_clear(3x)
                   clrtoeol                curs_clear(3x)
                   color_content           curs_color(3x)
                   color_set               curs_attr(3x)
                   copywin                 curs_overlay(3x)
                   curs_set                curs_kernel(3x)
                   curses_version          curs_extend(3x)*
                   def_prog_mode           curs_kernel(3x)
                   def_shell_mode          curs_kernel(3x)
                   define_key              define_key(3x)*
                   del_curterm             curs_terminfo(3x)
                   delay_output            curs_util(3x)
                   delch                   curs_delch(3x)
                   deleteln                curs_deleteln(3x)
                   delscreen               curs_initscr(3x)
                   delwin                  curs_window(3x)
                   derwin                  curs_window(3x)
                   doupdate                curs_refresh(3x)
                   dupwin                  curs_window(3x)
                   echo                    curs_inopts(3x)
                   echochar                curs_addch(3x)
                   endwin                  curs_initscr(3x)
                   erase                   curs_clear(3x)
                   erasechar               curs_termattrs(3x)
                   filter                  curs_util(3x)
                   flash                   curs_beep(3x)
                   flushinp                curs_util(3x)
                   getbegyx                curs_getyx(3x)
                   getbkgd                 curs_bkgd(3x)
                   getch                   curs_getch(3x)
                   getmaxyx                curs_getyx(3x)
                   getmouse                curs_mouse(3x)*
                   getnstr                 curs_getstr(3x)
                   getparyx                curs_getyx(3x)
                   getstr                  curs_getstr(3x)
                   getsyx                  curs_kernel(3x)
                   getwin                  curs_util(3x)
                   getyx                   curs_getyx(3x)
                   halfdelay               curs_inopts(3x)
                   has_colors              curs_color(3x)
                   has_ic                  curs_termattrs(3x)
                   has_il                  curs_termattrs(3x)
                   has_key                 curs_getch(3x)*
                   hline                   curs_border(3x)
                   idcok                   curs_outopts(3x)
                   idlok                   curs_outopts(3x)
                   immedok                 curs_outopts(3x)
                   inch                    curs_inch(3x)
                   inchnstr                curs_inchstr(3x)
                   inchstr                 curs_inchstr(3x)
                   init_color              curs_color(3x)
                   init_pair               curs_color(3x)
                   initscr                 curs_initscr(3x)

                   innstr                  curs_instr(3x)
                   insch                   curs_insch(3x)
                   insdelln                curs_deleteln(3x)
                   insertln                curs_deleteln(3x)
                   insnstr                 curs_insstr(3x)
                   insstr                  curs_insstr(3x)
                   instr                   curs_instr(3x)
                   intrflush               curs_inopts(3x)
                   is_linetouched          curs_touch(3x)
                   is_wintouched           curs_touch(3x)
                   isendwin                curs_initscr(3x)
                   keybound                keybound(3x)*
                   keyname                 curs_util(3x)
                   keyok                   keyok(3x)*
                   keypad                  curs_inopts(3x)
                   killchar                curs_termattrs(3x)
                   leaveok                 curs_outopts(3x)
                   longname                curs_termattrs(3x)
                   mcprint                 curs_print(3x)*
                   meta                    curs_inopts(3x)
                   mouse_trafo             curs_mouse(3x)*
                   mouseinterval           curs_mouse(3x)*
                   mousemask               curs_mouse(3x)*
                   move                    curs_move(3x)
                   mvaddch                 curs_addch(3x)
                   mvaddchnstr             curs_addchstr(3x)
                   mvaddchstr              curs_addchstr(3x)
                   mvaddnstr               curs_addstr(3x)
                   mvaddstr                curs_addstr(3x)
                   mvchgat                 curs_attr(3x)
                   mvcur                   curs_terminfo(3x)
                   mvdelch                 curs_delch(3x)
                   mvderwin                curs_window(3x)
                   mvgetch                 curs_getch(3x)
                   mvgetnstr               curs_getstr(3x)
                   mvgetstr                curs_getstr(3x)
                   mvhline                 curs_border(3x)
                   mvinch                  curs_inch(3x)
                   mvinchnstr              curs_inchstr(3x)
                   mvinchstr               curs_inchstr(3x)
                   mvinnstr                curs_instr(3x)
                   mvinsch                 curs_insch(3x)
                   mvinsnstr               curs_insstr(3x)
                   mvinsstr                curs_insstr(3x)
                   mvinstr                 curs_instr(3x)
                   mvprintw                curs_printw(3x)
                   mvscanw                 curs_scanw(3x)
                   mvvline                 curs_border(3x)
                   mvwaddch                curs_addch(3x)
                   mvwaddchnstr            curs_addchstr(3x)
                   mvwaddchstr             curs_addchstr(3x)
                   mvwaddnstr              curs_addstr(3x)
                   mvwaddstr               curs_addstr(3x)

                   mvwchgat                curs_attr(3x)
                   mvwdelch                curs_delch(3x)
                   mvwgetch                curs_getch(3x)
                   mvwgetnstr              curs_getstr(3x)
                   mvwgetstr               curs_getstr(3x)
                   mvwhline                curs_border(3x)
                   mvwin                   curs_window(3x)
                   mvwinch                 curs_inch(3x)
                   mvwinchnstr             curs_inchstr(3x)
                   mvwinchstr              curs_inchstr(3x)
                   mvwinnstr               curs_instr(3x)
                   mvwinsch                curs_insch(3x)
                   mvwinsnstr              curs_insstr(3x)
                   mvwinsstr               curs_insstr(3x)
                   mvwinstr                curs_instr(3x)
                   mvwprintw               curs_printw(3x)
                   mvwscanw                curs_scanw(3x)
                   mvwvline                curs_border(3x)
                   napms                   curs_kernel(3x)
                   newpad                  curs_pad(3x)
                   newterm                 curs_initscr(3x)
                   newwin                  curs_window(3x)
                   nl                      curs_outopts(3x)
                   nocbreak                curs_inopts(3x)
                   nodelay                 curs_inopts(3x)
                   noecho                  curs_inopts(3x)
                   nonl                    curs_outopts(3x)
                   noqiflush               curs_inopts(3x)
                   noraw                   curs_inopts(3x)
                   notimeout               curs_inopts(3x)
                   overlay                 curs_overlay(3x)
                   overwrite               curs_overlay(3x)
                   pair_content            curs_color(3x)
                   pechochar               curs_pad(3x)
                   pnoutrefresh            curs_pad(3x)
                   prefresh                curs_pad(3x)
                   printw                  curs_printw(3x)
                   putp                    curs_terminfo(3x)
                   putwin                  curs_util(3x)
                   qiflush                 curs_inopts(3x)
                   raw                     curs_inopts(3x)
                   redrawwin               curs_refresh(3x)
                   refresh                 curs_refresh(3x)
                   reset_prog_mode         curs_kernel(3x)
                   reset_shell_mode        curs_kernel(3x)
                   resetty                 curs_kernel(3x)
                   resizeterm              resizeterm(3x)*
                   restartterm             curs_terminfo(3x)
                   ripoffline              curs_kernel(3x)
                   savetty                 curs_kernel(3x)
                   scanw                   curs_scanw(3x)
                   scr_dump                curs_scr_dump(3x)
                   scr_init                curs_scr_dump(3x)

                   scr_restore             curs_scr_dump(3x)
                   scr_set                 curs_scr_dump(3x)
                   scrl                    curs_scroll(3x)
                   scroll                  curs_scroll(3x)
                   scrollok                curs_outopts(3x)
                   set_curterm             curs_terminfo(3x)
                   set_term                curs_initscr(3x)
                   setscrreg               curs_outopts(3x)
                   setsyx                  curs_kernel(3x)
                   setterm                 curs_terminfo(3x)
                   setupterm               curs_terminfo(3x)
                   slk_attr                curs_slk(3x)*
                   slk_attr_off            curs_slk(3x)
                   slk_attr_on             curs_slk(3x)
                   slk_attr_set            curs_slk(3x)
                   slk_attroff             curs_slk(3x)
                   slk_attron              curs_slk(3x)
                   slk_attrset             curs_slk(3x)
                   slk_clear               curs_slk(3x)
                   slk_color               curs_slk(3x)
                   slk_init                curs_slk(3x)
                   slk_label               curs_slk(3x)
                   slk_noutrefresh         curs_slk(3x)
                   slk_refresh             curs_slk(3x)
                   slk_restore             curs_slk(3x)
                   slk_set                 curs_slk(3x)
                   slk_touch               curs_slk(3x)
                   standend                curs_attr(3x)
                   standout                curs_attr(3x)
                   start_color             curs_color(3x)
                   subpad                  curs_pad(3x)
                   subwin                  curs_window(3x)
                   syncok                  curs_window(3x)
                   termattrs               curs_termattrs(3x)
                   termname                curs_termattrs(3x)
                   tgetent                 curs_termcap(3x)
                   tgetflag                curs_termcap(3x)
                   tgetnum                 curs_termcap(3x)
                   tgetstr                 curs_termcap(3x)
                   tgoto                   curs_termcap(3x)
                   tigetflag               curs_terminfo(3x)
                   tigetnum                curs_terminfo(3x)
                   tigetstr                curs_terminfo(3x)
                   timeout                 curs_inopts(3x)
                   touchline               curs_touch(3x)
                   touchwin                curs_touch(3x)
                   tparm                   curs_terminfo(3x)
                   tputs                   curs_termcap(3x)
                   tputs                   curs_terminfo(3x)
                   trace                   curs_trace(3x)*
                   typeahead               curs_inopts(3x)
                   unctrl                  curs_util(3x)
                   ungetch                 curs_getch(3x)

                   ungetmouse              curs_mouse(3x)*
                   untouchwin              curs_touch(3x)
                   use_default_colors      dft_fgbg(3x)*
                   use_env                 curs_util(3x)
                   use_extended_names      curs_extend(3x)*
                   vidattr                 curs_terminfo(3x)
                   vidputs                 curs_terminfo(3x)
                   vline                   curs_border(3x)
                   vw_printw               curs_printw(3x)
                   vw_scanw                curs_scanw(3x)
                   vwprintw                curs_printw(3x)
                   vwscanw                 curs_scanw(3x)
                   waddch                  curs_addch(3x)
                   waddchnstr              curs_addchstr(3x)
                   waddchstr               curs_addchstr(3x)
                   waddnstr                curs_addstr(3x)
                   waddstr                 curs_addstr(3x)
                   wattr_get               curs_attr(3x)
                   wattr_off               curs_attr(3x)
                   wattr_on                curs_attr(3x)
                   wattr_set               curs_attr(3x)
                   wattroff                curs_attr(3x)
                   wattron                 curs_attr(3x)
                   wattrset                curs_attr(3x)
                   wbkgd                   curs_bkgd(3x)
                   wbkgdset                curs_bkgd(3x)
                   wborder                 curs_border(3x)
                   wchgat                  curs_attr(3x)
                   wclear                  curs_clear(3x)
                   wclrtobot               curs_clear(3x)
                   wclrtoeol               curs_clear(3x)
                   wcolor_set              curs_attr(3x)
                   wcursyncup              curs_window(3x)
                   wdelch                  curs_delch(3x)
                   wdeleteln               curs_deleteln(3x)
                   wechochar               curs_addch(3x)
                   wenclose                curs_mouse(3x)*
                   werase                  curs_clear(3x)
                   wgetch                  curs_getch(3x)
                   wgetnstr                curs_getstr(3x)
                   wgetstr                 curs_getstr(3x)
                   whline                  curs_border(3x)
                   winch                   curs_inch(3x)
                   winchnstr               curs_inchstr(3x)
                   winchstr                curs_inchstr(3x)
                   winnstr                 curs_instr(3x)
                   winsch                  curs_insch(3x)
                   winsdelln               curs_deleteln(3x)
                   winsertln               curs_deleteln(3x)
                   winsnstr                curs_insstr(3x)
                   winsstr                 curs_insstr(3x)
                   winstr                  curs_instr(3x)
                   wmouse_trafo            curs_mouse(3x)*

                   wmove                   curs_move(3x)
                   wnoutrefresh            curs_refresh(3x)
                   wprintw                 curs_printw(3x)
                   wredrawln               curs_refresh(3x)
                   wrefresh                curs_refresh(3x)
                   wresize                 wresize(3x)*
                   wscanw                  curs_scanw(3x)
                   wscrl                   curs_scroll(3x)
                   wsetscrreg              curs_outopts(3x)
                   wstandend               curs_attr(3x)
                   wstandout               curs_attr(3x)
                   wsyncdown               curs_window(3x)
                   wsyncup                 curs_window(3x)
                   wtimeout                curs_inopts(3x)
                   wtouchln                curs_touch(3x)
                   wvline                  curs_border(3x)

## RETURN VALUE

           Routines  that  return  an integer return ERR upon failure
           and an integer value other than ERR upon  successful  com-
           pletion,  unless  otherwise  noted in the routine descrip-
           tions.

           All macros return the  value  of  the  w  version,  except
           setscrreg,  wsetscrreg,  getyx,  getbegyx,  getmaxyx.  The
           return values of setscrreg, wsetscrreg,  getyx,  getbegyx,
           and getmaxyx are undefined (i.e., these should not be used
           as the right-hand side of assignment statements).

           Routines that return pointers return NULL on error.

## ENVIRONMENT

           The following environment symbols are useful for customiz-
           ing the runtime behavior of the ncurses library.  The most
           important ones have been already discussed in detail.

           BAUDRATE
                The debugging library checks this environment  symbol
                when the application has redirected output to a file.
                The symbol's numeric value is used for the  baudrate.
                If  no value is found ncurses uses 9600.  This allows
                testers to construct repeatable test-cases that  take
                into account costs that depend on baudrate.

           CC   When set, change occurrences of the command_character
                (i.e., the cmdch capability) of the  loaded  terminfo
                entries  to  the value of this symbol.  Very few ter-
                minfo entries provide this feature.

           COLUMNS
                Specify  the  width  of  the  screen  in  characters.
                Applications  running in a windowing environment usu-
                ally are able to obtain the width of  the  window  in
                which  they  are  executing.  If neither the $COLUMNS
                value nor the terminal's screen  size  is  available,
                ncurses  uses  the size which may be specified in the
                terminfo database (i.e., the cols capability).

                It is important that your application use  a  correct
                size  for  the  screen.   However, this is not always
                possible because your application may be running on a
                host  which  does  not honor NAWS (Negotiations About
                Window Size), or because you are temporarily  running
                as another user.

                Either  COLUMNS  or  LINES  symbols  may be specified
                independently.  This is mainly useful  to  circumvent
                legacy  misfeatures  of  terminal descriptions, e.g.,
                xterm which commonly specifies a 65 line screen.  For
                best  results, lines and cols should not be specified
                in a terminal description for terminals which are run
                as emulations.

                Use the use_env function to disable this feature.

           ESCDELAY
                Specifies  the total time, in milliseconds, for which
                ncurses will await  a  character  sequence,  e.g.,  a
                function  key.  The default value, 1000 milliseconds,
                is enough for most uses.  However, it is made a vari-
                able to accommodate unusual applications.

                The most common instance where you may wish to change
                this value is to work with slow hosts, e.g.,  running
                on  a  network.   If  the host cannot read characters
                rapidly enough, it will have the same  effect  as  if
                the  terminal did not send characters rapidly enough.
                The library will still see a timeout.

                Note that xterm mouse events are built up from  char-
                acter  sequences  received  from  the xterm.  If your
                application makes heavy use of multiple-clicking, you
                may  wish  to lengthen this default value because the
                timeout applies to the composed multi-click event  as
                well as the individual clicks.

           HOME Tells  ncurses where your home directory is.  That is
                where  it  may  read  and  write  auxiliary  terminal
                descriptions:

                $HOME/.termcap
                $HOME/.terminfo

           LINES
                Like  COLUMNS,  specify  the  height of the screen in
                characters.  See COLUMNS for a detailed  description.

           MOUSE_BUTTONS_123
                This applies only to the OS/2 EMX port.  It specifies
                the order of buttons on the mouse.   OS/2  numbers  a
                3-button mouse inconsistently from other platforms:

                1 = left
                2 = right
                3 = middle.

                This symbol lets you customize the mouse.  The symbol
                must be three numeric digits 1-3 in any order,  e.g.,
                123  or  321.   If  it is not specified, ncurses uses
                132.

           NCURSES_NO_PADDING
                Most of the terminal  descriptions  in  the  terminfo
                database  are  written for real "hardware" terminals.
                Many people use terminal emulators  which  run  in  a
                windowing  environment  and use curses-based applica-
                tions.  Terminal emulators can duplicate all  of  the
                important aspects of a hardware terminal, but they do
                not have the same limitations.  The chief  limitation
                of  a  hardware  terminal from the standpoint of your
                application is the management of dataflow, i.e., tim-
                ing.  Unless a hardware terminal is interfaced into a
                terminal concentrator (which does flow  control),  it
                (or  your application) must manage dataflow, prevent-
                ing overruns.  The  cheapest  solution  (no  hardware
                cost) is for your program to do this by pausing after
                operations that the terminal  does  slowly,  such  as
                clearing the display.

                As  a  result,  many terminal descriptions (including
                the vt100) have delay times embedded.  You  may  wish
                to  use  these  descriptions, but not want to pay the
                performance penalty.

                Set the NCURSES_NO_PADDING symbol to disable all  but
                mandatory  padding.   Mandatory  padding is used as a
                part of special control sequences such as flash.

           NCURSES_NO_SETBUF
                Normally ncurses enables buffered output during  ter-
                minal  initialization.   This  is  done  (as  in SVr4
                curses) for performance reasons.   For  testing  pur-
                poses, both of ncurses and certain applications, this
                feature    is    made    optional.     Setting    the
                NCURSES_NO_SETBUF variable disables output buffering,
                leaving the output  in  the  original  (usually  line
                buffered) mode.

           NCURSES_TRACE
                During  initialization, the ncurses debugging library
                checks the NCURSES_TRACE symbol.  If it  is  defined,
                to a numeric value, ncurses calls the trace function,
                using that value as the argument.

                The argument values, which are defined  in  curses.h,
                provide  several  types of information.  When running
                with traces enabled, your application will write  the
                file trace to the current directory.

           TERM Denotes  your  terminal  type.  Each terminal type is
                distinct, though many are similar.

           TERMCAP
                If the ncurses library has been configured with term-
                cap  support,  ncurses  will  check  for a terminal's
                description in termcap form if it is not available in
                the terminfo database.

                The   TERMCAP   symbol  contains  either  a  terminal
                description (with newlines stripped out), or  a  file
                name  telling  where  the  information denoted by the
                TERM symbol  exists.   In  either  case,  setting  it
                directs  ncurses  to  ignore the usual place for this
                information, e.g., /etc/termcap.

           TERMINFO
                Overrides the directory in which ncurses searches for
                your terminal description.  This is the simplest, but
                not the only way to change the list  of  directories.
                The complete list of directories in order follows:

                -  the last directory to which ncurses wrote, if any,
                   is searched first.

                -  the directory specified by the TERMINFO symbol

                -  $HOME/.terminfo

                -  directories listed in the TERMINFO_DIRS symbol

                -  one or more directories whose names are configured
                   and  compiled  into  the  ncurses  library,  e.g.,
                   @DATADIR@/terminfo

           TERMINFO_DIRS
                Specifies a list of directories to search for  termi-
                nal  descriptions.   The  list is separated by colons
                (i.e., ":").  All of the terminal descriptions are in
                terminfo  form,  which makes a subdirectory named for
                the first letter of the terminal names therein.

           TERMPATH
                If TERMCAP does not hold a  file  name  then  ncurses
                checks  the TERMPATH symbol.  This is a list of file-
                names  separated  by  colons  (i.e.,  ":").   If  the
                TERMPATH  symbol  is  not  set,  ncurses looks in the
                files   /etc/termcap,   /usr/share/misc/termcap   and
                $HOME/.termcap, in that order.

## FILES

           @DATADIR@/tabset
                directory  containing  initialization  files  for the
                terminal capability database @DATADIR@/terminfo  ter-
                minal capability database

## SEE ALSO

           terminfo(5)  and  3x  pages  whose names begin "curs_" for
           detailed routine descriptions.

## EXTENSIONS

           The  ncurses  library  can  be  compiled  with  an  option
           (-DUSE_GETCAP) that falls back to the old-style /etc/term-
           cap file if the terminal setup code cannot find a terminfo
           entry  corresponding  to TERM.  Use of this feature is not
           recommended, as it essentially includes an entire  termcap
           compiler  in the ncurses startup code, at significant cost
           in core and startup cycles.

           The ncurses  library  includes  facilities  for  capturing
           mouse  events  on certain terminals (including xterm). See
           the curs_mouse(3x) manual page for details.

           The ncurses library includes facilities for responding  to
           window  resizing  events,  e.g., when running in an xterm.
           See the resizeterm(3x) and wresize(3x)  manual  pages  for
           details.   In addition, the library may be configured with
           a SIGWINCH handler.

           The ncurses library extends the fixed set of function  key
           capabilities  of  terminals  by  allowing  the application
           designer to define additional key  sequences  at  runtime.
           See  the  define_key(3x)  and  keyok(3x)  manual pages for
           details.

           The ncurses library can exploit the capabilities of termi-
           nals  which  implement the ISO-6429 SGR 39 and SGR 49 con-
           trols, which allow an application to reset the terminal to
           its  original  foreground and background colors.  From the
           users' perspective, the application is able to  draw  col-
           ored  text  on  a  background  whose color is set indepen-
           dently, providing better  control  over  color  contrasts.
           See the use_default_colors(3x) manual page for details.

           The  ncurses  library  includes  a  function for directing
           application output to a printer attached to  the  terminal
           device.  See the curs_print(3x) manual page for details.

## PORTABILITY

           The   ncurses   library   is  intended  to  be  BASE-level
           conformant with the XSI Curses standard.  Certain portions
           of  the EXTENDED XSI Curses functionality (including color
           support) are supported.  The following EXTENDED XSI Curses
           calls  in  support  of wide (multibyte) characters are not
           yet implemented: add_wch, add_wchnstr, add_wchstr,  addnw-
           str,  addwstr,  bkgrnd,  bkgrndset,  border_set,  box_set,
           echo_wchar,  erasewchar,  get_wch,  get_wstr,   getbkgrnd,
           getcchar,   getn_wstr,   getwchtype,   hline_set,  in_wch,
           in_wchnstr,  in_wchstr,   innwstr,   ins_nwstr,   ins_wch,
           ins_wstr,  inwchnstr,  inwchstr,  inwstr,  key_name, kill-
           wchar, mvadd_wch, mvadd_wchnstr, mvadd_wchstr, mvaddnwstr,
           mvaddwstr,   mvget_wch,   mvget_wstr,   mvgetn_wstr,  mvh-
           line_set,  mvin_wch,  mvinnwstr,  mvins_nwstr,  mvins_wch,
           mvins_wstr, mvinwchnstr, mvinwchstr, mvinwchstr, mvinwstr,
           mvvline_set,  mvwadd_wch,  mvwadd_wchnstr,  mvwadd_wchstr,
           mvwaddnwstr,     mvwaddwstr,     mvwget_ch,    mvwget_wch,
           mvwget_wstr,   mvwgetn_wstr,   mvwhline_set,    mvwin_wch,
           mvwin_wchnstr,   mvwin_wchstr,  mvwinnwstr,  mvwins_nwstr,
           mvwins_wch, mvwins_wstr, mvwinwchnstr.   mvwinwstr,  mvwv-
           line_set,  pecho_wchar,  setcchar,  slk_wset,  term_attrs,
           unget_wch,  vhline_set,  vid_attr,  vid_puts,   vline_set,
           wadd_wch,  wadd_wchnstr, wadd_wchstr, waddnwstr, waddwstr,
           waddwstr, wbkgrnd,  wbkgrndset,  wbkgrndset,  wborder_set,
           wecho_wchar, wecho_wchar, wget_wch, wget_wstr, wgetbkgrnd,
           wgetn_wstr, whline_set, win_wch, win_wchnstr,  win_wchstr,
           winnwstr,  wins_nwstr,  wins_wch,  wins_wstr,  winwchnstr,
           winwchstr, winwstr, wunctrl, wvline_set,

           A small number of local differences (that  is,  individual
           differences  between the XSI Curses and ncurses calls) are
           described in  PORTABILITY  sections  of  the  library  man
           pages.

           The routine has_key is not part of XPG4, nor is it present
           in SVr4.  See the curs_getch(3x) manual page for  details.

           The  routine  slk_attr is not part of XPG4, nor is it pre-
           sent in  SVr4.   See  the  curs_slk(3x)  manual  page  for
           details.

           The  routines getmouse, mousemask, ungetmouse, mouseinter-
           val, and wenclose relating to mouse  interfacing  are  not
           part  of  XPG4,  nor  are  they  present in SVr4.  See the
           curs_mouse(3x) manual page for details.

           The routine mcprint was not present in any previous curses
           implementation.   See  the  curs_print(3x) manual page for
           details.

           The routine wresize is not part of XPG4, nor is it present
           in SVr4.  See the wresize(3x) manual page for details.

           In  historic curses versions, delays embedded in the capa-
           bilities cr, ind, cub1, ff and tab activated corresponding
           delay  bits  in  the UNIX tty driver.  In this implementa-
           tion, all padding is done by NUL sends.   This  method  is
           slightly  more expensive, but narrows the interface to the
           UNIX kernel  significantly  and  increases  the  package's
           portability correspondingly.

           In  the  XSI  standard  and  SVr4 manual pages, many entry
           points have prototype arguments of the for char *const (or
           cchar_t  *const,  or  wchar_t  *const,  or  void  *const).
           Depending on one's interpretation of the ANSI  C  standard
           (see  section  3.5.4.1), these declarations are either (a)
           meaningless, or (b) meaningless and illegal.  The declara-
           tion const char *x is a modifiable pointer to unmodifiable
           data, but char *const x' is  an  unmodifiable  pointer  to
           modifiable  data.  Given that C passes arguments by value,
           <type> *const as a formal type is at best  dubious.   Some
           compilers  choke  on  the  prototypes.  Therefore, in this
           implementation, they have been changed to const  <type>  *
           globally.

## NOTES

           The  header  file  <curses.h>  automatically  includes the
           header files <stdio.h> and <unctrl.h>.

           If standard output from a ncurses program  is  re-directed
           to  something  which  is not a tty, screen updates will be
           directed to standard error.  This was an undocumented fea-
           ture of AT&T System V Release 3 curses.

## AUTHORS

           Zeyd  M.  Ben-Halim,  Eric  S.  Raymond, Thomas E. Dickey.
           Based on pcurses by Pavel Curtis.