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ncurses(3)                                                          ncurses(3)




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 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 6.4 (patch 20221231).

       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 PORTABILITY sections
       below and described in detail in the respective EXTENSIONS, PORTABILITY
       and BUGS sections of individual man pages.

       The ncurses library also provides many useful extensions, i.e., features
       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 ALTERNATE CONFIGURATIONS.

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

   Initialization
       The library uses the locale which the calling program has initialized.
       That is normally done with setlocale(3):

           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(3X) 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:

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

       Before a curses program is run, the tab stops of the terminal 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.]

   Datatypes
       The ncurses library permits manipulation of data structures, 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 windows 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 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(3X) 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 information.

       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 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.

   Environment variables
       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
       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 compiled
       terminal definition is found in

           /opt/local/share/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

           /opt/local/share/terminfo/a/att4424.

       This is useful for developing experimental definitions or when write
       permission in /opt/local/share/terminfo is not available.

       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
       routines.

   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
       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.  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
       configuration of the library.  There are two common configurations of the
       library:

          ncurses
               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 chtype.

          ncursesw
               the so-called "wide" library, which handles multibyte characters
               (see the section on ALTERNATE CONFIGURATIONS).  The "wide"
               library includes all of the calls from the "normal" library.  It
               adds about one third more calls using data types which store
               multibyte characters:

               cchar_t
                    corresponds to chtype.  However it is a structure, because
                    more data is stored than can fit into an integer.  The
                    characters are large enough to require a full integer value
                    - and there may be more than one character per cell.  The
                    video attributes and color are stored in separate fields of
                    the structure.

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

                    The setcchar(3X) and getcchar(3X) functions store and
                    retrieve the data from a cchar_t structure.

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

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

               The "wide" library provides new functions which are analogous to
               functions in the "normal" library.  There is a naming convention
               which relates many of the normal/wide variants: a "_w" is
               inserted into the name.  For example, waddch becomes wadd_wch.

   Routine Name Index
       The following table lists the curses routines provided in the "normal"
       and "wide" libraries and the names of the manual pages on which they are
       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)
                     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)
                     alloc_pair               new_pair(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)
                     attron                   curs_attr(3X)
                     attrset                  curs_attr(3X)
                     baudrate                 curs_termattrs(3X)
                     beep                     curs_beep(3X)
                     bkgd                     curs_bkgd(3X)
                     bkgdset                  curs_bkgd(3X)
                     bkgrnd                   curs_bkgrnd(3X)
                     bkgrndset                curs_bkgrnd(3X)
                     border                   curs_border(3X)
                     border_set               curs_border_set(3X)
                     box                      curs_border(3X)
                     box_set                  curs_border_set(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_trace             curs_trace(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)
                     exit_curses              curs_memleaks(3X)*
                     exit_terminfo            curs_memleaks(3X)*
                     extended_color_content   curs_color(3X)*
                     extended_pair_content    curs_color(3X)*
                     extended_slk_color       curs_slk(3X)*
                     filter                   curs_util(3X)
                     find_pair                new_pair(3X)*
                     flash                    curs_beep(3X)
                     flushinp                 curs_util(3X)
                     free_pair                new_pair(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)*
                     getpary                  curs_legacy(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)*
                     has_mouse                curs_mouse(3X)*
                     hline                    curs_border(3X)
                     hline_set                curs_border_set(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_extended_color      curs_color(3X)*
                     init_extended_pair       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_pad                   curs_opaque(3X)*
                     is_scrollok              curs_opaque(3X)*
                     is_subwin                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)*
                     mouseinterval            curs_mouse(3X)*
                     mousemask                curs_mouse(3X)*
                     move                     curs_move(3X)
                     mvadd_wch                curs_add_wch(3X)
                     mvadd_wchnstr            curs_add_wchstr(3X)
                     mvadd_wchstr             curs_add_wchstr(3X)
                     mvaddch                  curs_addch(3X)
                     mvaddchnstr              curs_addchstr(3X)
                     mvaddchstr               curs_addchstr(3X)
                     mvaddnstr                curs_addstr(3X)
                     mvaddnwstr               curs_addwstr(3X)
                     mvaddstr                 curs_addstr(3X)
                     mvaddwstr                curs_addwstr(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)
                     mvwin                    curs_window(3X)
                     mvwin_wch                curs_in_wch(3X)
                     mvwin_wchnstr            curs_in_wchstr(3X)
                     mvwin_wchstr             curs_in_wchstr(3X)
                     mvwinch                  curs_inch(3X)
                     mvwinchnstr              curs_inchstr(3X)
                     mvwinchstr               curs_inchstr(3X)
                     mvwinnstr                curs_instr(3X)
                     mvwinnwstr               curs_inwstr(3X)
                     mvwins_nwstr             curs_ins_wstr(3X)
                     mvwins_wch               curs_ins_wch(3X)
                     mvwins_wstr              curs_ins_wstr(3X)
                     mvwinsch                 curs_insch(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_inopts(3X)
                     nocbreak                 curs_inopts(3X)
                     nodelay                  curs_inopts(3X)
                     noecho                   curs_inopts(3X)
                     nofilter                 curs_util(3X)*
                     nonl                     curs_inopts(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)
                     pecho_wchar              curs_pad(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_color_pairs        curs_color(3X)*
                     reset_prog_mode          curs_kernel(3X)
                     reset_shell_mode         curs_kernel(3X)
                     resetty                  curs_kernel(3X)
                     resize_term              resizeterm(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)
                     setscrreg                curs_outopts(3X)
                     setsyx                   curs_kernel(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)
                     slk_wset                 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)
                     tiparm                   curs_terminfo(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)
                     wadd_wch                 curs_add_wch(3X)
                     wadd_wchnstr             curs_add_wchstr(3X)
                     wadd_wchstr              curs_add_wchstr(3X)
                     waddch                   curs_addch(3X)
                     waddchnstr               curs_addchstr(3X)
                     waddchstr                curs_addchstr(3X)
                     waddnstr                 curs_addstr(3X)
                     waddnwstr                curs_addwstr(3X)
                     waddstr                  curs_addstr(3X)
                     waddwstr                 curs_addwstr(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)
                     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)
                     wgetdelay                curs_opaque(3X)*
                     wgetn_wstr               curs_get_wstr(3X)
                     wgetnstr                 curs_getstr(3X)
                     wgetparent               curs_opaque(3X)*
                     wgetscrreg               curs_opaque(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)
                     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)
                     wunctrl                  curs_util(3X)
                     wvline                   curs_border(3X)
                     wvline_set               curs_border_set(3X)

       Depending on the configuration, additional sets of functions may be
       available:

          curs_memleaks(3X) - curses memory-leak checking

          curs_sp_funcs(3X) - curses screen-pointer extension

          curs_threads(3X) - curses thread support

          curs_trace(3X) - curses debugging routines


RETURN VALUE

       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 parameters,
       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
       statements).

       Functions with a "mv" prefix first perform a cursor movement using wmove,
       and return an error if the position is outside the window, or if the
       window pointer is null.  Most "mv"-prefixed functions (except variadic
       functions such as mvprintw) are provided both as macros and functions.

       Routines that return pointers return NULL on error.


ENVIRONMENT

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

   CC command-character
       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 represent
       the C compiler's name, ncurses ignores it if it does not happen to be a
       single character.

   BAUDRATE
       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.

   COLUMNS
       Specify the width of the screen in characters.  Applications running 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 user.  However, setting
       COLUMNS and/or LINES overrides the library's use of the screen size
       obtained from the operating system.

       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 all use of external environment (but
       not including system calls) to determine the screen size.  Use the
       use_tioctl function to update COLUMNS or LINES to match the screen size
       obtained from system calls or the terminal database.

   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 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 provides 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:

           $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 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.

   NCURSES_ASSUMED_COLORS
       Override the compiled-in assumption that the terminal's default colors
       are white-on-black (see default_colors(3X)).  You may set the foreground
       and background color values with this environment variable by proving a
       2-element list: foreground,background.  For example, to tell ncurses to
       not assume anything about the colors, set this to "-1,-1".  To make it
       green-on-black, set it to "2,0".  Any positive value from zero to the
       terminfo max_colors value is allowed.

   NCURSES_CONSOLE2
       This applies only to the MinGW port of ncurses.

       The Console2 program's handling of the Microsoft Console API call
       CreateConsoleScreenBuffer is defective.  Applications which use this will
       hang.  However, it is possible to simulate the action of this call by
       mapping coordinates, explicitly saving and restoring the original screen
       contents.  Setting the environment variable NCGDB has the same effect.

   NCURSES_GPM_TERMS
       This applies only to ncurses configured to use the GPM interface.

       If present, the environment variable is a list of one or more terminal
       names against which the TERM environment variable is matched.  Setting it
       to an empty value disables the GPM interface; 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_NO_HARD_TABS
       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(1) settings to avoid the problem.

   NCURSES_NO_MAGIC_COOKIE
       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.

   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 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.

   NCURSES_NO_SETBUF
       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 (usually line buffered) mode.

       In the current implementation, ncurses performs its own buffering and
       does not require this workaround.  It does not modify the buffering of
       the standard output.

       The reason for the change was to make the behavior for interrupts and
       other signals more robust.  One drawback is that certain nonconventional
       programs would mix ordinary stdio calls with ncurses calls and (usually)
       work.  This is no longer possible since ncurses is not using the buffered
       standard output but its own output (to the same file descriptor).  As a
       special case, the low-level calls such as putp still use the standard
       output.  But high-level curses calls do not.

   NCURSES_NO_UTF8_ACS
       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.

   NCURSES_TRACE
       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 several types
       of information.  When running with traces enabled, your application will
       write the file trace to the current directory.

       See curs_trace(3X) for more information.

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

       TERM is commonly set by terminal emulators to help applications find a
       workable terminal description.  Some of those choose a popular
       approximation, e.g., "ansi", "vt100", "xterm" rather than an exact fit.
       Not infrequently, your application will have problems with that approach,
       e.g., incorrect function-key definitions.

       If you set TERM in your environment, it has no effect on the operation of
       the terminal emulator.  It only affects the way applications work within
       the terminal.  Likewise, as a general rule (xterm(1) being a rare
       exception), terminal emulators which allow you to specify TERM as a
       parameter or configuration value do not change their behavior to match
       that setting.

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

   TERMINFO
       ncurses can be configured to read from multiple terminal databases.  The
       TERMINFO variable overrides the location for the default terminal
       database.  Terminal descriptions (in terminal format) are stored in
       terminal databases:

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

           This is the scheme used in System V, which legacy Unix systems use,
           and the TERMINFO variable is used by curses applications on those
           systems to override the default location of the terminal database.

       o   If ncurses is built to use hashed databases, then each entry in this
           list may be the path of a hashed database file, e.g.,

               /usr/share/terminfo.db

           rather than

               /usr/share/terminfo/

           The hashed database uses less disk-space and is a little faster than
           the directory tree.  However, some applications assume the existence
           of the directory tree, reading it directly rather than using the
           terminfo library calls.

       o   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
           file.

       o   If the TERMINFO variable begins with "hex:" or "b64:", ncurses uses
           the remainder of that variable as a compiled terminal description.
           You might produce the base64 format using infocmp(1M):

               TERMINFO="$(infocmp -0 -Q2 -q)"
               export TERMINFO

           The compiled description is used if it corresponds to the terminal
           identified by the TERM variable.

       Setting TERMINFO is the simplest, but not the only way to set location of
       the default terminal database.  The complete list of database locations
       in order follows:

          o   the last terminal database to which ncurses wrote, if any, is
              searched first

          o   the location specified by the TERMINFO environment variable

          o   $HOME/.terminfo

          o   locations listed in the TERMINFO_DIRS environment variable

          o   one or more locations whose names are configured and compiled into
              the ncurses library, i.e.,

             o   no default value (corresponding to the TERMINFO_DIRS variable)

             o   /opt/local/share/terminfo (corresponding to the TERMINFO
                 variable)

   TERMINFO_DIRS
       Specifies a list of locations to search for terminal descriptions.  Each
       location in the list is a terminal database as described in the section
       on the TERMINFO variable.  The list is separated by colons (i.e., ":") on
       Unix, semicolons on OS/2 EMX.

       There is no corresponding feature in System V terminfo; it is an
       extension developed for ncurses.

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

       If the TERMPATH environment variable is not set, ncurses looks in the
       files

           /etc/termcap, /usr/share/misc/termcap and $HOME/.termcap,

       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.


ALTERNATE CONFIGURATIONS

       Several different configurations are possible, depending on the configure
       script options used when building ncurses.  There are a few main options
       whose effects are visible to the applications developer using ncurses:

       --disable-overwrite
            The standard include for ncurses is as noted in SYNOPSIS:

                #include <curses.h>

            This option is used to avoid filename conflicts when ncurses is not
            the main implementation of curses of the computer.  If ncurses is
            installed disabling overwrite, it puts its headers in a
            subdirectory, e.g.,

                #include <ncurses/curses.h>

            It also omits a symbolic link which would allow you to use -lcurses
            to build executables.

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

                -lncurses

            you link with

                -lncursesw

            You must also enable the wide-character features in the header file
            when compiling for the wide-character library to use the extended
            (wide-character) functions.  The symbol which enables these features
            has changed since XSI Curses, Issue 4:

            o   Originally, the wide-character feature required the symbol
                _XOPEN_SOURCE_EXTENDED but that was only valid for XPG4 (1996).

            o   Later, that was deemed conflicting with _XOPEN_SOURCE defined to
                500.

            o   As of mid-2018, none of the features in this implementation
                require a _XOPEN_SOURCE feature greater than 600.  However,
                X/Open Curses, Issue 7 (2009) recommends defining it to 700.

            o   Alternatively, you can enable the feature by defining
                NCURSES_WIDECHAR with the caveat that some other header file
                than curses.h may require a specific value for _XOPEN_SOURCE (or
                a system-specific symbol).

            The curses.h file which is installed for the wide-character 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.

       --with-pthread
            The configure script renames the library.  All of the library names
            have a "t" appended to them (before any "w" added by
            --enable-widec).

            The global variables such as LINES are replaced by macros to allow
            read-only access.  At the same time, setter-functions are provided
            to set these values.  Some applications (very few) may require
            changes to work with this convention.

       --with-shared

       --with-normal

       --with-debug

       --with-profile
            The shared and normal (static) library names differ by their
            suffixes, e.g., libncurses.so and libncurses.a.  The debug and
            profiling libraries add a "_g" and a "_p" to the root names
            respectively, e.g., libncurses_g.a and libncurses_p.a.

       --with-termlib
            Low-level functions which do not depend upon whether the library
            supports wide-characters, are provided in the tinfo library.

            By doing this, it is possible to share the tinfo library between
            wide/normal configurations as well as reduce the size of the library
            when only low-level functions are needed.

            Those functions are described in these pages:

            o   curs_extend(3X) - miscellaneous curses extensions

            o   curs_inopts(3X) - curses input options

            o   curs_kernel(3X) - low-level curses routines

            o   curs_termattrs(3X) - curses environment query routines

            o   curs_termcap(3X) - curses emulation of termcap

            o   curs_terminfo(3X) - curses interfaces to terminfo database

            o   curs_util(3X) - miscellaneous curses utility routines

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


FILES

       /opt/local/share/tabset
            directory containing initialization files for the terminal
            capability database /opt/local/share/terminfo terminal capability
            database


SEE ALSO

       terminfo(5) and related pages whose names begin "curs_" for detailed
       routine descriptions.
       curs_variables(3X)
       user_caps(5) for user-defined capabilities


EXTENSIONS

       The ncurses library can be compiled with an option (-DUSE_GETCAP) that
       falls back to the old-style /etc/termcap 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) 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
       background 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_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 XSI
       Curses.  The EXTENDED XSI Curses functionality (including color support)
       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.

   Error checking
       In many cases, X/Open Curses is vague about error conditions, omitting
       some of the SVr4 documentation.

       Unlike other implementations, this one checks parameters such as pointers
       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.

   Extensions versus portability
       Most of the extensions provided by ncurses have not been standardized.
       Some have been incorporated into other implementations, such as PDCurses
       or NetBSD curses.  Here are a few to consider:

       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
           details.

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

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

       o   The WINDOW structure's internal details can be hidden from
           application programs.  See curs_opaque(3X) for the discussion of
           is_scrollok, etc.

       o   This implementation can be configured to provide rudimentary support
           for multi-threaded applications.  See curs_threads(3X) for details.

       o   This implementation can also be configured to provide a set of
           functions which improve the ability to manage multiple screens.  See
           curs_sp_funcs(3X) for details.

   Padding differences
       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 interface
       to the UNIX kernel significantly and increases the package's portability
       correspondingly.

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

       X/Open Curses has more to say, but does not finish the story:

           The inclusion of <curses.h> may make visible all symbols from the
           headers <stdio.h>, <term.h>, <termios.h>, and <wchar.h>.

       Here is a more complete story:

       o   Starting with BSD curses, all implementations have included
           <stdio.h>.

           BSD curses included <curses.h> and <unctrl.h> from an internal header
           "curses.ext" ("ext" was a short name for externs).

           BSD curses used <stdio.h> internally (for printw and scanw), but
           nothing in <curses.h> itself relied upon <stdio.h>.

       o   SVr2 curses added newterm(3X), which relies upon <stdio.h>.  That is,
           the function prototype uses FILE.

           SVr4 curses added putwin and getwin, which also use <stdio.h>.

           X/Open Curses documents all three of these functions.

           SVr4 curses and X/Open Curses do not require the developer to include
           <stdio.h> before including <curses.h>.  Both document curses showing
           <curses.h> as the only required header.

           As a result, standard <curses.h> will always include <stdio.h>.

       o   X/Open Curses is inconsistent with respect to SVr4 regarding
           <unctrl.h>.

           As noted in curs_util(3X), ncurses includes <unctrl.h> from
           <curses.h> (like SVr4).

       o   X/Open's comments about <term.h> and <termios.h> may refer to HP-UX
           and AIX:

           HP-UX curses includes <term.h> from <curses.h> to declare setupterm
           in curses.h, but ncurses (and Solaris curses) do not.

           AIX curses includes <term.h> and <termios.h>.  Again, ncurses (and
           Solaris curses) do not.

       o   X/Open says that <curses.h> may include <term.h>, but there is no
           requirement that it do that.

           Some programs use functions declared in both <curses.h> and <term.h>,
           and must include both headers in the same module.  Very old versions
           of AIX curses required including <curses.h> before including
           <term.h>.

           Because ncurses header files include the headers needed to define
           datatypes used in the headers, ncurses header files can be included
           in any order.  But for portability, you should include <curses.h>
           before <term.h>.

       o   X/Open Curses says "may make visible" because including a header file
           does not necessarily make all symbols in it visible (there are
           ifdef's to consider).

           For instance, in ncurses <wchar.h> may be included if the proper
           symbol is defined, and if ncurses is configured for wide-character
           support.  If the header is included, its symbols may be made visible.
           That depends on the value used for _XOPEN_SOURCE feature test macro.

       o   X/Open Curses documents one required header, in a special case:
           <stdarg.h> before <curses.h> to prototype the vw_printw and vw_scanw
           functions (as well as the obsolete the vwprintw and vwscanw
           functions).  Each of those uses a va_list parameter.

           The two obsolete functions were introduced in SVr3.  The other
           functions were introduced in X/Open Curses.  In between, SVr4 curses
           provided for the possibility that an application might include either
           <varargs.h> or <stdarg.h>.  Initially, that was done by using void*
           for the va_list parameter.  Later, a special type (defined in
           <stdio.h>) was introduced, to allow for compiler type-checking.  That
           special type is always available, because <stdio.h> is always
           included by <curses.h>.

           None of the X/Open Curses implementations require an application to
           include <stdarg.h> before <curses.h> because they either have allowed
           for a special type, or (like ncurses) include <stdarg.h> directly to
           provide a portable interface.


NOTES

       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.


AUTHORS

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



                                                                     ncurses(3)

ncurses 6.4 - Generated Fri Jan 6 15:57:38 CST 2023
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