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       #include <curses.h>


       The  ncurses  library  routines  give  the  user a terminal-independent
       method of updating  character  screens  with  reasonable  optimization.
       This  implementation  is  ``new  curses'' (ncurses) and is the approved
       replacement for 4.4BSD classic curses,  which  has  been  discontinued.
       This describes ncurses version 5.9 (patch 20130511).

       The  ncurses  library emulates the curses library of System V Release 4
       UNIX, and XPG4 (X/Open Portability Guide) curses  (also  known  as  XSI
       curses).   XSI  stands  for  X/Open  System  Interfaces Extension.  The
       ncurses library is freely redistributable in source form.   Differences
       from  the SVr4 curses are summarized under the EXTENSIONS and PORTABIL-
       ITY sections below and described in detail  in  the  respective  EXTEN-
       SIONS, PORTABILITY and BUGS sections of individual man pages.

       The  ncurses  library  also provides many useful extensions, i.e., fea-
       tures which cannot be implemented by a simple add-on library but  which
       require access to the internals of the library.

       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
       directory) that describe curses  actions.   See  also  the  section  on

       The  ncurses package supports: overall screen, window and pad manipula-
       tion; output to windows and pads; reading terminal input; control  over
       terminal  and  curses  input and output options; environment query rou-
       tines; color manipulation; use of soft label keys;  terminfo  capabili-
       ties; and access to low-level terminal-manipulation routines.

       The  library uses the locale which the calling program has initialized.
       That is normally done with setlocale:

             setlocale(LC_ALL, "");

       If the locale is not initialized, the library assumes  that  characters
       are  printable  as in ISO-8859-1, to work with certain legacy programs.
       You should initialize the locale and not rely on  specific  details  of
       the library when the locale has not been setup.

       The  function  initscr  or  newterm  must  be  called to initialize the
       library 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
       for doing this.  [See terminfo(5) for further details.]

       The  ncurses  library  permits  manipulation of data structures, called
       windows, which can be thought of as two-dimensional arrays  of  charac-
       ters 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 windows and not using stdscr at all.  Mix-
       ing 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 those, 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 displayed.  See curs_pad(3X) for more informa-

       In addition to drawing characters on the screen, video  attributes  and
       colors  may  be  supported,  causing  the characters 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 val-
       ues.  The video attributes, line drawing characters, and  input  values
       use  names,  defined  in  <curses.h>, such as A_REVERSE, ACS_HLINE, and

       If the environment variables LINES and COLUMNS are set, or if the  pro-
       gram  is executing in a window environment, line and column information
       in the environment will override information read  by  terminfo.   This
       would affect 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  program  using
       curses  checks  for  a local terminal definition before checking in the
       standard place.  For example, if TERM is set to att4424, then the  com-
       piled terminal definition is found in

       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 values 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  rou-

   Routine and Argument Names
       Many  curses routines have two or more versions.  The routines prefixed
       with w require a window argument.  The routines prefixed with p require
       a pad argument.  Those without 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  coor-

       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.  Most of the data types used in
       the library routines, such as WINDOW,  SCREEN,  bool,  and  chtype  are
       defined  in  <curses.h>.   Types used for the terminfo routines such as
       TERMINAL are defined in <term.h>.

       This manual page describes functions which may appear in any configura-
       tion  of  the  library.   There  are  two  common configurations of the

                   the "normal" library, which handles 8-bit characters.   The
                   normal  (8-bit)  library  stores  characters  combined with
                   attributes in chtype data.

                   Attributes alone (no corresponding character) may be stored
                   in  chtype  or the equivalent attr_t data.  In either case,
                   the data is stored in something like an integer.

                   Each cell (row and column) in  a  WINDOW  is  stored  as  a

                   the so-called "wide" library, which handles multibyte char-

                        stores  a  "wide" character.  Like chtype, this may be
                        an integer.

                        stores a wchar_t or WEOF - not the same,  though  both
                        may have the same size.

                   The  "wide" library provides new functions which are analo-
                   gous to functions in the "normal" library.  There is a nam-
                   ing  convention which relates many of the normal/wide vari-
                   ants: a "_w" is inserted into the name.  For example,  wad-
                   dch becomes wadd_wch.

   Routine Name Index
       The  following table lists each curses routine and the name of the man-
       ual 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_free_and_exit       curs_memleaks(3X)*
                     _nc_freeall             curs_memleaks(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)*
                     add_wch                 curs_add_wch(3X)
                     add_wchnstr             curs_add_wchstr(3X)
                     add_wchstr              curs_add_wchstr(3X)
                     addch                   curs_addch(3X)
                     addchnstr               curs_addchstr(3X)
                     addchstr                curs_addchstr(3X)
                     addnstr                 curs_addstr(3X)
                     addnwstr                curs_addwstr(3X)
                     addstr                  curs_addstr(3X)
                     addwstr                 curs_addwstr(3X)
                     assume_default_colors   default_colors(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)
                     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)
                     echo_wchar              curs_add_wch(3X)
                     echochar                curs_addch(3X)
                     endwin                  curs_initscr(3X)
                     erase                   curs_clear(3X)
                     erasechar               curs_termattrs(3X)
                     erasewchar              curs_termattrs(3X)
                     filter                  curs_util(3X)
                     flash                   curs_beep(3X)
                     flushinp                curs_util(3X)
                     get_wch                 curs_get_wch(3X)
                     get_wstr                curs_get_wstr(3X)
                     getattrs                curs_attr(3X)
                     getbegx                 curs_legacy(3X)*
                     getbegy                 curs_legacy(3X)*
                     getbegyx                curs_getyx(3X)
                     getbkgd                 curs_bkgd(3X)
                     getbkgrnd               curs_bkgrnd(3X)
                     getcchar                curs_getcchar(3X)
                     getch                   curs_getch(3X)
                     getcurx                 curs_legacy(3X)*
                     getcury                 curs_legacy(3X)*
                     getmaxx                 curs_legacy(3X)*
                     getmaxy                 curs_legacy(3X)*
                     getmaxyx                curs_getyx(3X)
                     getmouse                curs_mouse(3X)*
                     getn_wstr               curs_get_wstr(3X)
                     getnstr                 curs_getstr(3X)
                     getparx                 curs_legacy(3X)*
                     idcok                   curs_outopts(3X)
                     idlok                   curs_outopts(3X)
                     immedok                 curs_outopts(3X)
                     in_wch                  curs_in_wch(3X)
                     in_wchnstr              curs_in_wchstr(3X)
                     in_wchstr               curs_in_wchstr(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)
                     innwstr                 curs_inwstr(3X)
                     ins_nwstr               curs_ins_wstr(3X)
                     ins_wch                 curs_ins_wch(3X)
                     ins_wstr                curs_ins_wstr(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)
                     inwstr                  curs_inwstr(3X)
                     is_cleared              curs_opaque(3X)*
                     is_idcok                curs_opaque(3X)*
                     is_idlok                curs_opaque(3X)*
                     is_immedok              curs_opaque(3X)*
                     is_keypad               curs_opaque(3X)*
                     is_leaveok              curs_opaque(3X)*
                     is_linetouched          curs_touch(3X)
                     is_nodelay              curs_opaque(3X)*
                     is_notimeout            curs_opaque(3X)*
                     is_scrollok             curs_opaque(3X)*
                     is_syncok               curs_opaque(3X)*
                     is_term_resized         resizeterm(3X)*
                     is_wintouched           curs_touch(3X)
                     isendwin                curs_initscr(3X)
                     key_defined             key_defined(3X)*
                     key_name                curs_util(3X)
                     keybound                keybound(3X)*
                     keyname                 curs_util(3X)
                     keyok                   keyok(3X)*
                     keypad                  curs_inopts(3X)
                     killchar                curs_termattrs(3X)
                     killwchar               curs_termattrs(3X)
                     leaveok                 curs_outopts(3X)
                     longname                curs_termattrs(3X)
                     mcprint                 curs_print(3X)*
                     meta                    curs_inopts(3X)
                     mouse_trafo             curs_mouse(3X)*
                     mvchgat                 curs_attr(3X)
                     mvcur                   curs_terminfo(3X)
                     mvdelch                 curs_delch(3X)
                     mvderwin                curs_window(3X)
                     mvget_wch               curs_get_wch(3X)
                     mvget_wstr              curs_get_wstr(3X)
                     mvgetch                 curs_getch(3X)
                     mvgetn_wstr             curs_get_wstr(3X)
                     mvgetnstr               curs_getstr(3X)
                     mvgetstr                curs_getstr(3X)
                     mvhline                 curs_border(3X)
                     mvhline_set             curs_border_set(3X)
                     mvin_wch                curs_in_wch(3X)
                     mvin_wchnstr            curs_in_wchstr(3X)
                     mvin_wchstr             curs_in_wchstr(3X)
                     mvinch                  curs_inch(3X)
                     mvinchnstr              curs_inchstr(3X)
                     mvinchstr               curs_inchstr(3X)
                     mvinnstr                curs_instr(3X)
                     mvinnwstr               curs_inwstr(3X)
                     mvins_nwstr             curs_ins_wstr(3X)
                     mvins_wch               curs_ins_wch(3X)
                     mvins_wstr              curs_ins_wstr(3X)
                     mvinsch                 curs_insch(3X)
                     mvinsnstr               curs_insstr(3X)
                     mvinsstr                curs_insstr(3X)
                     mvinstr                 curs_instr(3X)
                     mvinwstr                curs_inwstr(3X)
                     mvprintw                curs_printw(3X)
                     mvscanw                 curs_scanw(3X)
                     mvvline                 curs_border(3X)
                     mvvline_set             curs_border_set(3X)
                     mvwadd_wch              curs_add_wch(3X)
                     mvwadd_wchnstr          curs_add_wchstr(3X)
                     mvwadd_wchstr           curs_add_wchstr(3X)
                     mvwaddch                curs_addch(3X)
                     mvwaddchnstr            curs_addchstr(3X)
                     mvwaddchstr             curs_addchstr(3X)
                     mvwaddnstr              curs_addstr(3X)
                     mvwaddnwstr             curs_addwstr(3X)
                     mvwaddstr               curs_addstr(3X)
                     mvwaddwstr              curs_addwstr(3X)
                     mvwchgat                curs_attr(3X)
                     mvwdelch                curs_delch(3X)
                     mvwget_wch              curs_get_wch(3X)
                     mvwget_wstr             curs_get_wstr(3X)
                     mvwgetch                curs_getch(3X)
                     mvwgetn_wstr            curs_get_wstr(3X)
                     mvwgetnstr              curs_getstr(3X)
                     mvwgetstr               curs_getstr(3X)
                     mvwhline                curs_border(3X)
                     mvwhline_set            curs_border_set(3X)
                     mvwinsnstr              curs_insstr(3X)
                     mvwinsstr               curs_insstr(3X)
                     mvwinstr                curs_instr(3X)
                     mvwinwstr               curs_inwstr(3X)
                     mvwprintw               curs_printw(3X)
                     mvwscanw                curs_scanw(3X)
                     mvwvline                curs_border(3X)
                     mvwvline_set            curs_border_set(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)
                     nofilter                curs_util(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)
                     setcchar                curs_getcchar(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)
                     term_attrs              curs_termattrs(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)
                     unget_wch               curs_get_wch(3X)
                     ungetch                 curs_getch(3X)
                     ungetmouse              curs_mouse(3X)*
                     untouchwin              curs_touch(3X)
                     use_default_colors      default_colors(3X)*
                     use_env                 curs_util(3X)
                     use_extended_names      curs_extend(3X)*
                     use_legacy_coding       legacy_coding(3X)*
                     use_tioctl              curs_util(3X)
                     vid_attr                curs_terminfo(3X)
                     vid_puts                curs_terminfo(3X)
                     vidattr                 curs_terminfo(3X)
                     vidputs                 curs_terminfo(3X)
                     vline                   curs_border(3X)
                     vline_set               curs_border_set(3X)
                     vw_printw               curs_printw(3X)
                     vw_scanw                curs_scanw(3X)
                     vwprintw                curs_printw(3X)
                     vwscanw                 curs_scanw(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)
                     wbkgrnd                 curs_bkgrnd(3X)
                     wbkgrndset              curs_bkgrnd(3X)
                     wborder                 curs_border(3X)
                     wborder_set             curs_border_set(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)
                     wecho_wchar             curs_add_wch(3X)
                     wechochar               curs_addch(3X)
                     wenclose                curs_mouse(3X)*
                     werase                  curs_clear(3X)
                     wget_wch                curs_get_wch(3X)
                     wget_wstr               curs_get_wstr(3X)
                     wgetbkgrnd              curs_bkgrnd(3X)
                     wgetch                  curs_getch(3X)
                     wgetn_wstr              curs_get_wstr(3X)
                     wgetnstr                curs_getstr(3X)
                     wgetstr                 curs_getstr(3X)
                     whline                  curs_border(3X)
                     whline_set              curs_border_set(3X)
                     win_wch                 curs_in_wch(3X)
                     win_wchnstr             curs_in_wchstr(3X)
                     win_wchstr              curs_in_wchstr(3X)
                     winch                   curs_inch(3X)
                     winchnstr               curs_inchstr(3X)
                     winchstr                curs_inchstr(3X)
                     winnstr                 curs_instr(3X)
                     winnwstr                curs_inwstr(3X)
                     wins_nwstr              curs_ins_wstr(3X)
                     wins_wch                curs_ins_wch(3X)
                     wins_wstr               curs_ins_wstr(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)
                     winwstr                 curs_inwstr(3X)
                     wmouse_trafo            curs_mouse(3X)*
                     wmove                   curs_move(3X)
                     wnoutrefresh            curs_refresh(3X)

                     wvline                  curs_border(3X)
                     wvline_set              curs_border_set(3X)


       Routines  that return an integer return ERR upon failure and an integer
       value other than ERR upon successful completion, unless otherwise noted
       in the routine descriptions.

       As  a  general rule, routines check for null pointers passed as parame-
       ters, and handle this as an error.

       All macros return  the  value  of  the  w  version,  except  setscrreg,
       wsetscrreg,  getyx,  getbegyx,  and  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

       Routines that return pointers return NULL on error.


       The following environment symbols are useful for customizing  the  run-
       time  behavior  of  the  ncurses library.  The most important ones have
       been already discussed in detail.

            The debugging library checks this environment  variable  when  the
            application  has  redirected  output  to  a  file.  The variable'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 variable.  Very few terminfo entries provide this feature.

            Because this name is also used in development environments to rep-
            resent  the  C  compiler's name, ncurses ignores it if it does not
            happen to be a single character.

            Specify the width of the screen in characters.  Applications  run-
            ning  in  a  windowing  environment usually 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.  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
            match  the  screen size obtained from system calls or the terminal

            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 variable 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 character 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.

            In  addition to the environment variable, this implementation pro-
            vides a global variable with the same name.  Portable applications
            should  not rely upon the presence of ESCDELAY in either form, but
            setting the environment variable rather than the  global  variable
            does not create problems when compiling an application.

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


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

            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  inconsis-
            tently from other platforms:

            1 = left
            2 = right
            3 = middle.

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

            Override  the  compiled-in  assumption that the terminal's default
            using the built-in support for xterm, etc.

            If  the  environment  variable  is absent, ncurses will attempt to
            open GPM if TERM contains "linux".

            Ncurses may use tabs as part of the cursor movement  optimization.
            In some cases, your terminal driver may not handle these properly.
            Set this environment variable to disable  the  feature.   You  can
            also adjust your stty settings to avoid the problem.

            Some  terminals  use a magic-cookie feature which requires special
            handling to make highlighting and other video  attributes  display
            properly.   You  can  suppress the highlighting entirely for these
            terminals by setting this environment variable.

            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  applications.   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., timing.  Unless a hardware terminal is interfaced
            into a terminal concentrator (which does  flow  control),  it  (or
            your  application) must manage dataflow, preventing 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 environment variable to disable all but
            mandatory padding.  Mandatory padding is used as a part of special
            control sequences such as flash.

            This setting is obsolete.  Before changes

            o   started with 5.9 patch 20120825 and

            o   continued though 5.9 patch 20130126

            ncurses enabled buffered output  during  terminal  initialization.
            This  was  done  (as in SVr4 curses) for performance reasons.  For
            testing purposes, both of ncurses and certain  applications,  this
            feature was made optional.  Setting the NCURSES_NO_SETBUF variable
            disabled output buffering, leaving  the  output  in  the  original

            During initialization, the  ncurses  library  checks  for  special
            cases  where  VT100  line-drawing (and the corresponding alternate
            character set capabilities) described in the terminfo are known to
            be  missing.   Specifically,  when  running in a UTF-8 locale, the
            Linux console emulator and the GNU screen  program  ignore  these.
            Ncurses checks the TERM environment variable for these.  For other
            special cases, you should set this  environment  variable.   Doing
            this  tells  ncurses to use Unicode values which correspond to the
            VT100 line-drawing glyphs.   That  works  for  the  special  cases
            cited, and is likely to work for terminal emulators.

            When  setting this variable, you should set it to a nonzero value.
            Setting it to zero (or to a nonnumber) disables the special  check
            for "linux" and "screen".

            As  an alternative to the environment variable, ncurses checks for
            an extended terminfo capability U8.  This is a numeric  capability
            which can be compiled using tic -x.  For example

            # linux console, if patched to provide working
            # VT100 shift-in/shift-out, with corresponding font.
            linux-vt100|linux console with VT100 line-graphics,
                    U8#0, use=linux,

            # uxterm with vt100Graphics resource set to false
            xterm-utf8|xterm relying on UTF-8 line-graphics,
                    U8#1, use=xterm,

            The  name  "U8" is chosen to be two characters, to permit it to be
            used by applications that use ncurses' termcap interface.

            During initialization, the ncurses debugging  library  checks  the
            NCURSES_TRACE  environment  variable.   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 sev-
            eral 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.

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

            The  TERMCAP  environment  variable  contains  either  a  terminal
            o   the directory specified by the TERMINFO environment variable

            o   $HOME/.terminfo

            o   directories listed in the TERMINFO_DIRS environment variable

            o   one or more directories whose names are  configured  and  com-
                piled into the ncurses library, i.e.,

                o   no default value (corresponding to the TERMINFO_DIRS vari-

                o   /usr/share/terminfo (corresponding to the  TERMINFO  vari-

            Specifies  a  list  of directories to search for terminal descrip-
            tions.  The list is separated by colons (i.e., ":") on Unix, semi-
            colons on OS/2 EMX.

            All  of  the terminal descriptions are in terminfo form.  Normally
            these are stored in a directory tree, using  subdirectories  named
            by the first letter of the terminal names therein.

            If  ncurses  is  built  with a hashed database, then each entry in
            this list can also be the path of the corresponding database file.

            If ncurses is built with  a  support  for  reading  termcap  files
            directly,  then an entry in this list may be the path of a termcap

            If TERMCAP does not hold a  file  name  then  ncurses  checks  the
            TERMPATH  environment variable.  This is a list of filenames sepa-
            rated by spaces or colons (i.e., ":") on Unix, semicolons on  OS/2

            If  the TERMPATH environment variable is not set, ncurses looks in
            the files /etc/termcap, /usr/share/misc/termcap  and  $HOME/.term-
            cap, in that order.

       The library may be configured to disregard the following variables when
       the current user is the superuser (root), or if  the  application  uses
       setuid or setgid permissions:

              $TERMINFO, $TERMINFO_DIRS, $TERMPATH, as well as $HOME.


       Several different configurations are possible, depending on the config-
       ure script options used when building ncurses.  There are  a  few  main
       options  whose  effects are visible to the applications developer using
            -lcurses to build executables.

            The configure script  renames  the  library  and  (if  the  --dis-
            able-overwrite  option is used) puts the header files in a differ-
            ent subdirectory.  All of the library names have a "w" appended to
            them, i.e., instead of


            you link with


            You must also define _XOPEN_SOURCE_EXTENDED when compiling for the
            wide-character library to use the extended (wide-character)  func-
            tions.   The curses.h file which is installed for the wide-charac-
            ter library is designed to be compatible with the normal library's
            header.   Only  the size of the WINDOW structure differs, and very
            few applications require more than a pointer to WINDOWs.   If  the
            headers  are  installed  allowing  overwrite,  the  wide-character
            library's headers should be installed last, to allow  applications
            to be built using either library from the same set of headers.




            The  shared and normal (static) library names differ by their suf-
            fixes, e.g., libncurses.so and libncurses.a.  The debug  and  pro-
            filing  libraries  add a "_g" and a "_p" to the root names respec-
            tively, e.g., libncurses_g.a and libncurses_p.a.

            The trace function normally resides in the debug library,  but  it
            is sometimes useful to configure this in the shared library.  Con-
            figure scripts should check for the  function's  existence  rather
            than assuming it is always in the debug library.


            directory  containing  initialization files for the terminal capa-
            bility database /usr/share/terminfo terminal capability database


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

       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) key_defined(3X), and
       keyok(3X) manual pages for details.

       The ncurses library can exploit the  capabilities  of  terminals  which
       implement  the  ISO-6429  SGR  39  and  SGR 49 controls, which allow an
       application to reset the terminal to its original foreground and  back-
       ground colors.  From the users' perspective, the application is able to
       draw colored text on a background whose  color  is  set  independently,
       providing  better  control  over color contrasts.  See the default_col-
       ors(3X) manual page for details.

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


       The ncurses library is intended to be BASE-level  conformant  with  XSI
       Curses.   The  EXTENDED  XSI Curses functionality (including color sup-
       port) is supported.

       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.

       Unlike other implementations, this one checks parameters such as point-
       ers  to WINDOW structures to ensure they are not null.  The main reason
       for providing this behavior is to guard against programmer error.   The
       standard  interface  does  not provide a way for the library to tell an
       application which of several possible errors were detected.  Relying on
       this (or some other) extension will adversely affect the portability of
       curses applications.

       This implementation also contains several extensions:

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

       o   The  routine  slk_attr  is  not  part of XPG4, nor is it present in
           SVr4.  See the curs_slk(3X) manual page for details.

       o   The routines getmouse, mousemask,  ungetmouse,  mouseinterval,  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

       o   The  routine  mcprint was not present in any previous curses imple-
           mentation.  See the curs_print(3X) manual page for details.
           See curs_sp_funcs(3X) for details.

       In  historic  curses  versions, delays embedded in the capabilities cr,
       ind, cub1, ff and tab activated corresponding delay bits  in  the  UNIX
       tty driver.  In this implementation, all padding is done by sending NUL
       bytes.  This method is slightly more expensive, but narrows the  inter-
       face  to  the  UNIX  kernel  significantly  and increases the package's
       portability correspondingly.


       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 feature of AT&T System V Release 3 curses.


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

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