ncurses 3x 2024-04-13 ncurses 6.4 Library calls

ncurses(3x)                      Library calls                     ncurses(3x)


       ncurses - character-cell terminal interface with optimized output


       #include <curses.h>


       The  "new  curses" library offers the programmer a terminal-independent
       means of reading keyboard and mouse input and  updating  character-cell
       terminals  with  output  optimized to minimize screen updates.  ncurses
       replaces the curses libraries from System V Release 4 Unix ("SVr4") and
       4.4BSD  Unix,  the  development  of  which  ceased  in the 1990s.  This
       describes ncurses version 6.4 (patch 20240413).

       ncurses permits control of the terminal screen's contents;  abstraction
       and  subdivision thereof with windows and pads; the reading of terminal
       input; control of terminal input and output options; environment  query
       routines;  color  manipulation;  the  definition  and use of soft label
       keys; terminfo capability access; a  termcap  compatibility  interface;
       and  an  abstraction  of the system's API for manipulating the terminal
       (such as termios(3)).

       ncurses implements the standard interface described  by  X/Open  Curses
       Issue 7.   In  many  behavioral  details  not  standardized  by X/Open,
       ncurses emulates the curses  library  of  SVr4  and  provides  numerous
       useful extensions.

       ncurses  man  pages employ several sections to clarify matters of usage
       and interoperability with other curses implementations.

       o   "NOTES" describes issues and caveats  of  which  any  user  of  the
           ncurses  API should be aware, such as limitations on the size of an
           underlying integral type or  the  availability  of  a  preprocessor
           macro  exclusive  of  a  function  definition  (which  prevents its
           address  from  being   taken).    This   section   also   describes
           implementation  details  that will be significant to the programmer
           but which are not standardized.

       o   "EXTENSIONS" presents ncurses innovations beyond the X/Open  Curses
           standard  and/or  the  SVr4 curses implementation.  They are termed
           extensions to indicate that they cannot be  implemented  solely  by
           using the library API, but require access to the library's internal

       o   "PORTABILITY" discusses matters (beyond the exercise of extensions)
           that should be considered when writing to a curses standard, or for
           multiple implementations.

       o   "HISTORY" examines points of detail in  ncurses  and  other  curses
           implementations over the decades of their development, particularly
           where precedent or inertia have frustrated better design (and, in a
           few cases, where such inertia has been overcome).

       A curses application must be linked with the library; use the -lncurses
       option to your compiler or linker.  A debugging version of the  library
       may  be available; if so, link with it using -lncurses_g.  (Your system
       integrator may have installed these libraries such that you can use the
       options  -lcurses and -lcurses_g, respectively.)  The ncurses_g library
       generates trace logs (in a file called trace in the current  directory)
       that  describe ncurses actions.  See section "ALTERNATE CONFIGURATIONS"

Application Structure

       A  curses  application  uses  information  from  the   system   locale;
       setlocale(3) prepares it for curses library calls.

           setlocale(LC_ALL, "");

       If  the  locale  is  not  thus  initialized,  the  library assumes that
       characters are printable as in ISO 8859-1, to work with certain  legacy
       programs.   You  should initialize the locale; do not expect consistent
       behavior from the library when the locale has not been set up.

       initscr(3x) or newterm(3x) must be called to initialize  curses  before
       use of any functions that deal with windows and screens.

       To  get  character-at-a-time  input  without echoing--most interactive,
       screen-oriented programs want this--use the following sequence.

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

       Most applications perform further setup as follows.

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

       A curses program then often enters an event loop of  some  sort.   Call
       endwin(3x) before exiting.


       A  curses  library abstracts the terminal screen by representing all or
       part of it as a WINDOW data structure.  A window is a rectangular  grid
       of  character  cells,  addressed  by row and column coordinates (y, x),
       with the upper left corner as (0, 0).  A window called stdscr, the same
       size  as  the terminal screen, is always available.  Create others with

       A curses library does not manage overlapping windows (but  see  below).
       You  can either use stdscr to manage one screen-filling window, or tile
       the screen into non-overlapping windows and  not  use  stdscr  at  all.
       Mixing  the  two  approaches will result in unpredictable and undesired

       Functions permit manipulation of a window and  the  cursor  identifying
       the  cell  within  it  at  which  the next output operation will occur.
       Among those, the most basic are move(3x) and addch(3x): these place the
       cursor and write a character to stdscr, respectively.

       Frequent changes to the terminal screen can cause unpleasant flicker or
       inefficient use of the communication channel  to  the  device,  so  the
       library  does  not generally update it automatically.  Therefore, after
       using curses functions to accumulate a set of desired updates that make
       sense to present together, call refresh(3x) to tell the library to make
       the user's screen look like stdscr.  The library optimizes  its  output
       by  computing  a minimal number of operations to mutate the screen from
       its  state  at  the  previous  refresh  to  the  new  one.    Effective
       optimization  demands  accurate  information about the terminal device:
       the management of such information is the province of the  terminfo(3x)
       API, a feature of every standard curses implementation.

       Special windows called pads may also be manipulated.  These are windows
       that are not constrained to the size of the terminal screen  and  whose
       contents need not be completely displayed.  See curs_pad(3x).

       In  addition  to drawing characters on the screen, rendering 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.  See curs_attr(3x).

       curses predefines constants for a small set of  forms-drawing  graphics
       corresponding  to  the  DEC Alternate Character Set (ACS), a feature of
       VT100 and other terminals.  See waddch(3x).

       curses is implemented using the  operating  system's  terminal  driver;
       keystroke  events are received not as scan codes but as byte sequences.
       Graphical keycaps (alphanumeric and punctuation keys,  and  the  space)
       appear  as-is.   Everything  else,  including  the  tab,  enter/return,
       keypad, arrow, and function keys, appears as a control character  or  a
       multibyte  escape  sequence.   curses  translates these into unique key
       codes.  See getch(3x).

       ncurses provides reimplementations of the SVr4 panel(3x), form(3x), and
       menu(3x) libraries to ease construction of user interfaces with curses.


       The   selection  of  an  appropriate  value  of  TERM  in  the  process
       environment  is  essential  to  correct  curses  and  terminfo  library
       operation.   A  well-configured  system  selects  a  correct TERM value
       automatically;  tset(1)  may   assist   with   troubleshooting   exotic

       If  you  change the terminal type, export the TERM environment variable
       in the shell, then  run  tset(1)  or  the  "tput  init"  command.   See
       subsection "Tabs and Initialization" of terminfo(5).

       If  the  environment  variables  LINES  and  COLUMNS are set, or if the
       curses program is executing in a graphical windowing  environment,  the
       information  obtained  thence  overrides that obtained by terminfo.  An
       ncurses extension supports resizable terminals; see wresize(3x).

       If the environment variable  TERMINFO  is  defined,  a  curses  program
       checks  first  for  a  terminal  type  description  in  the location it
       identifies.   TERMINFO  is  useful  for  developing  experimental  type
       descriptions  or  when  write  permission to /usr/share/terminfo is not

       See section "ENVIRONMENT" below.

Naming Conventions

       curses offers many functions in variant forms using a  regular  set  of
       alternatives  to the name of an elemental one.  Those prefixed with "w"
       require a WINDOW pointer argument;  those  with  a  "mv"  prefix  first
       perform cursor movement using wmove(3x); a "mvw" prefix indicates both.
       The "w" function is typically the elemental one; the  removal  of  this
       prefix usually indicates operation on stdscr.

       Four functions prefixed with "p" require a pad argument.

       In  function  synopses,  ncurses man pages apply the following names to

                       bf    bool (TRUE or FALSE)
                       win   pointer to a WINDOW
                       pad   pointer to a WINDOW that is a pad

Wide and Non-wide Character Configurations

       This manual page describes functions that appear in  any  configuration
       of  the  library.   There  are  two  common configurations; see section

       ncurses   is the library in its "non-wide" configuration, handling only
                 eight-bit  characters.   It  stores a character combined with
                 attributes in a chtype datum, which is often an alias of int.

                 Attributes alone (with no  corresponding  character)  can  be
                 stored  in  variables  of  chtype  or attr_t type.  In either
                 case, they are represented as an integral bit mask.

                 Each cell of a WINDOW is stored as a chtype.

       ncursesw  is the library in its  "wide"  configuration,  which  handles
                 character encodings requiring a larger data type than char (a
                 byte-sized type) can represent.  It adds about one third more
                 calls  using  additional  data  types  that  can  store  such
                 multibyte characters.

                 cchar_t  corresponds to the non-wide configuration's  chtype.
                          It  always  a structure type, because it stores more
                          data than  fit  into  a  standard  scalar  type.   A
                          character  code  may not be representable as a char,
                          and moreover more than one character  may  occupy  a
                          cell  (as  with  accent marks and other diacritics).
                          Each  character  is  of  type  wchar_t;  a   complex
                          character contains one spacing character and zero or
                          more non-spacing characters (see below).  Attributes
                          and  color data are stored in separate fields of the
                          structure, not combined as in chtype.

                 Each cell of a WINDOW is stored as a cchar_t.

                 setcchar(3x) and  getcchar(3x)  store  and  retrieve  cchar_t
                 data.   The  wide  library API of ncurses depends on two data
                 types standardized by ISO C95.

                 wchar_t  stores a wide character.  Like chtype, it may be  an
                          alias  of int.  Depending on the character encoding,
                          a wide character may be  spacing,  meaning  that  it
                          occupies  a  character  cell by itself and typically
                          accompanies  cursor  advancement,  or   non-spacing,
                          meaning  that it occupies the same cell as a spacing
                          character, is often regarded as a "modifier" of  the
                          base  glyph  with  which  it combines, and typically
                          does not advance the cursor.

                 wint_t   can  store  a  wchar_t   or   the   constant   WEOF,
                          analogously  to the int-sized character manipulation
                          functions of ISO C and its constant EOF.

                 The  wide  library   provides   additional   functions   that
                 complement  those  in  the non-wide library where the size of
                 the underlying character type  is  significant.   A  somewhat
                 regular  naming  convention relates many of the wide variants
                 to their non-wide counterparts;  where  a  non-wide  function
                 name  contains  "ch"  or "str", prefix it with "_w" to obtain
                 the wide counterpart.  For example, waddch becomes  wadd_wch.
                 (Exceptions  that  add only "w" comprise addwstr, inwstr, and
                 their variants.)

                 This convention is inapplicable  to  some  non-wide  function
                 names,  so  other  transformations  are  used  for  the  wide
                 configuration:  the  window  background  management  function
                 "bkgd"   becomes  "bkgrnd";  the  window  border-drawing  and
                 -clearing functions are suffixed with "_set";  and  character
                 attribute   manipulation   functions   like  "attron"  become

Function Name Index

       The following table lists the curses functions provided in the non-wide
       and  wide  APIs  and  the  corresponding  man pages that describe them.
       Those flagged with  "*"  are  ncurses-specific,  neither  described  by
       X/Open Curses nor present in SVr4.

                    curses Function Name     Man Page
                    COLOR_PAIR               curs_color(3x)
                    PAIR_NUMBER              curs_color(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_escdelay             curs_threads(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_cbreak                curs_inopts(3x)*
                    is_cleared               curs_opaque(3x)*
                    is_echo                  curs_inopts(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_nl                    curs_inopts(3x)*
                    is_nodelay               curs_opaque(3x)*
                    is_notimeout             curs_opaque(3x)*
                    is_pad                   curs_opaque(3x)*
                    is_raw                   curs_inopts(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_escdelay             curs_threads(3x)*
                    set_tabsize              curs_threads(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)
                    tiparm_s                 curs_terminfo(3x)*
                    tiscan_s                 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_screen               curs_threads(3x)*
                    use_tioctl               curs_util(3x)*
                    use_window               curs_threads(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)

       ncurses's    screen-pointer   extension   adds   additional   functions
       corresponding to many of the above, each  with  an  "_sp"  suffix;  see

       The  availability  of  some  extensions is configurable when ncurses is
       compiled; see  sections  "ALTERNATE  CONFIGURATIONS"  and  "EXTENSIONS"


       Unless  otherwise  noted, functions that return an integer return OK on
       success and ERR on failure.  Functions that return pointers return NULL
       on  failure.   Typically,  ncurses  treats  a  null pointer passed as a
       function parameter as a failure.  Functions with a  "mv"  prefix  first
       perform  cursor  movement  using  wmove(3x) and fail if the position is
       outside the window.


       The following  symbols  from  the  process  environment  customize  the
       runtime   behavior   of  ncurses  applications.   The  library  may  be
       configured  to  disregard  the   variables   TERMINFO,   TERMINFO_DIRS,
       TERMPATH,  and  HOME,  if  the  user  is  the  superuser (root), or the
       application uses setuid(2) or setgid(2).


       The debugging library checks this variable  when  the  application  has
       redirected  output  to a file.  Its integral value is used for the baud
       rate.  If that value is absent or invalid,  ncurses  uses  9600.   This
       feature  allows  testers  to  construct repeatable test cases that take
       into account optimization decisions that depend on baud rate.

CC (command character)

       When set, the command_character  (cmdch)  capability  value  of  loaded
       terminfo entries changes to the value of this variable.  Very few term-
       info entries provide this feature.

       Because this name is also used in development environments to represent
       the  C  compiler's  name,  ncurses  ignores  its value if it is not one
       character in length.


       This  variable  specifies  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 COLUMNS
       is not defined and the terminal's screen size is not available from the
       terminal driver, ncurses uses the size specified by the columns  (cols)
       capability  of  the  terminal type's entry in the terminfo database, if

       It is important that your application  use  the  correct  screen  size.
       Automatic   detection   thereof  is  not  always  possible  because  an
       application may  be  running  on  a  host  that  does  not  honor  NAWS
       (Negotiations  About  Window  Size)  or as a different user ID than the
       owner of the  terminal  device  file.   Setting  COLUMNS  and/or  LINES
       overrides  the  library's  use  of  the  screen  size obtained from the
       operating system.

       The COLUMNS and LINES variables may be specified  independently.   This
       property  is  useful  to circumvent misfeatures of legacy terminal type
       descriptions; xterm(1)  descriptions  specifying  65  lines  were  once
       notorious.    For   best  results,  avoid  specifying  cols  and  lines
       capability codes in terminfo descriptions of terminal emulators.

       use_env(3x) can disable use of the process environment  in  determining
       the  screen size.  use_tioctl(3x) can update COLUMNS and LINES to match
       the screen size obtained from system calls or the terminal database.


       For curses to distinguish the ESC character  resulting  from  a  user's
       press  of  the  "Escape"  key on the input device from one beginning an
       escape sequence (as commonly produced by function keys), it waits after
       receiving  the  escape  character  to  see  if  further  characters are
       available on the input  stream  within  a  short  interval.   A  global
       variable  ESCDELAY  stores  this interval in milliseconds.  The default
       value of 1000 (one second) is adequate for most uses.  This environment
       variable overrides it.

       The  most common instance where you may wish to change this value is to
       work with a remote host over a slow communication channel.  If the host
       running  a  curses  application  does  not receive the characters of an
       escape sequence in a timely manner, the library can interpret  them  as
       multiple key stroke events.

       xterm(1) mouse events are a form of escape sequence; therefore, if your
       application makes heavy use  of  multiple-clicking,  you  may  wish  to
       lengthen  the  default value because the delay applies to the composite
       multi-click event as well as the individual clicks.

       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.

       If keypad(3x) is disabled for the  curses  window  receiving  input,  a
       program must disambiguate escape sequences itself.


       ncurses  may read and write auxiliary terminal descriptions in .termcap
       and .terminfo files in the user's home directory.


       This counterpart to COLUMNS specifies  the  height  of  the  screen  in
       characters.   The  corresponding terminfo capability and code is lines.
       See the description of the COLUMNS variable above.


       (OS/2 EMX port only) OS/2 numbers a three-button  mouse  inconsistently
       with  other platforms, such that 1 is the left button, 2 the right, and
       3 the middle.  This variable customizes  the  mouse  button  numbering.
       Its  value  must be three digits 1-3 in any order.  By default, ncurses
       assumes a numbering of "132".


       If set, this  variable  overrides  the  ncurses  library's  compiled-in
       assumption  that  the terminal's default colors are white on black; see
       default_colors(3x).  Set the foreground  and  background  color  values
       with  this  environment  variable  by  assigning  it two integer values
       separated  by  a  comma,  indicating  foregound  and  background  color
       numbers, respectively.

       For  example,  to tell ncurses not to assume anything about the colors,
       use a value of "-1,-1".  To make the  default  color  scheme  green  on
       black,  use  "2,0".   ncurses accepts integral values from -1 up to the
       value of the terminfo max_colors (colors) capability.


       (MinGW  port  only)  The  Console2  program  defectively  handles   the
       Microsoft  Console  API  call  CreateConsoleScreenBuffer.  Applications
       that use it 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.


       (Linux  only) When ncurses is configured to use the GPM interface, this
       variable may list one or more terminal names  against  which  the  TERM
       variable  (see  below)  is  matched.   An  empty value disables the GPM
       interface,  using  ncurses's  built-in  support  for   xterm(1)   mouse
       protocols instead.  If the variable is absent, ncurses attempts to open
       GPM if TERM contains "linux".


       ncurses may use tab characters in  cursor  movement  optimization.   In
       some  cases,  your  terminal  driver may not handle them properly.  Set
       this environment variable to any value to disable the feature.  You can
       also adjust your stty(1) settings to avoid the problem.


       Many  terminals  store  video  attributes  as a property of a character
       cell, as curses does.  Historically, some  recorded  changes  in  video
       attributes  as  data  that  logically  occupies  character cells on the
       display, switching attributes on or off, similarly to tags in a  markup
       language;  these  are  termed "magic cookies", and must be subsequently
       overprinted.  If the terminfo entry for your  terminal  type  does  not
       adequately describe its handling of magic cookies, set this variable to
       any value to instruct ncurses to disable attributes entirely.


       Most  terminal  type  descriptions  in  the  terminfo  database  detail
       hardware   devices.   Many  people  use  curses-based  applications  in
       terminal emulator programs that run in a windowing environment.   These
       programs  can  duplicate  all  of  the important features of a hardware
       terminal, but often lack their limitations.  Chief among  these  absent
       drawbacks is the problem of data flow management; that is, limiting the
       speed of communication to what the hardware  could  handle.   Unless  a
       hardware  terminal  is  interfaced  into a terminal concentrator (which
       does flow control), an application must manage flow control  itself  to
       prevent overruns and data loss.

       A  solution  that  comes  at  no hardware cost is for an application to
       pause after directing a  terminal  to  execute  an  operation  that  it
       performs  slowly,  such  as  clearing  the display.  Many terminal type
       descriptions, including that for the VT100, embed delay  specifications
       in  capabilities.   You  may  wish  to  use these temrinal descriptions
       without paying the performance penalty.  Set NCURSES_NO_PADDING to  any
       value  to disable all but mandatory padding.  Mandatory padding is used
       by such terminal capabilities as flash_screen (flash).


       (Obsolete) Prior to internal changes developed in ncurses 5.9  (patches
       20120825  through 20130126), the library used setbuf(3) to enable fully
       buffered output when initializing the terminal.  This was done,  as  in
       SVr4  curses,  to  increase performance.  For testing purposes, both of
       ncurses and of certain applications, this feature  was  made  optional.
       Setting  this  variable  disabled  output buffering, leaving the output
       stream in the original (usually line-buffered) mode.

       Nowadays, ncurses performs its own buffering and does not require  this
       workaround;  it  does  not  modify the buffering of the standard output
       stream.  This approach makes signal handling, as for  interrupts,  more
       robust.   A  drawback  is  that  certain  unconventional programs mixed
       stdio(3) calls with ncurses calls and (usually) got the  behavior  they
       expected.   This  is  no longer the case; ncurses does not write to the
       standard output file descriptor through a stdio-buffered stream.

       As a special case, low-level API calls such as putp(3x) still  use  the
       standard  output stream.  High-level curses calls such as printw(3x) do


       At initialization, ncurses inspects the TERM environment  variable  for
       special   cases   where   VT100   forms-drawing   characters  (and  the
       corresponding alternate character set terminfo capabilities) are  known
       to  be  unsupported  by  terminal  types  that  otherwise  claim  VT100
       compatibility.  Specifically, when running in a UTF-8 locale, the Linux
       virtual  console device and the GNU screen(1) program ignore them.  Set
       this  variable  to  a  nonzero  value  to  instruct  ncurses  that  the
       terminal's ACS support is broken; the library then outputs Unicode code
       points that correspond to the forms-drawing characters.  Set it to zero
       (or a non-integer) to disable the special check for terminal type names
       matching "linux" or "screen", directing ncurses to assume that the  ACS
       feature works if the terminal type description advertises it.

       As  an  alternative  to  use  of  this  variable, ncurses checks for an
       extended terminfo numeric capability U8 that can be compiled using "tic
       -x".  Examples follow.

          # 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  two-character name "U8" was chosen to permit its use via ncurses's
       termcap interface.


       At initialization, ncurses (in its debugging configuration) checks  for
       this  variable's  presence.   If  defined  with  an integral value, the
       library calls curses_trace(3x) with that value as the argument.


       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.


       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.


       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.,


           rather than


           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

       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   /usr/share/terminfo   (corresponding   to  the  TERMINFO_DIRS

             o   /usr/share/terminfo (corresponding to the TERMINFO variable)


       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.


       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

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

       in that order.


       Many  different  ncurses configurations are possible, determined by the
       options given to the configure script when building the  library.   Run
       the  script  with  the  --help option to peruse them all.  A few are of
       particular significance to the application developer employing ncurses.

            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.

            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


            you link with


            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

            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 header file installed for the wide-character  library
            is  designed  to be compatible with the non-wide library's header.
            Only the size of the WINDOW structure  differs;  few  applications
            require more than pointers 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

            The configure script renames the  library.   All  of  the  library
            names  have  a  "t"  appended  to  them  (before  any "w" added by

            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.




            The  shared  and  normal  (static)  library  names differ by their
            suffixes, e.g., 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.

            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 interface to terminfo database

            o   curs_util(3x) - miscellaneous curses utility routines

            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.


              tab stop initialization database

              compiled terminal capability database


       X/Open Curses permits most functions it specifies to be made  available
       as macros as well.  ncurses does so

       o   for functions that return values via their parameters,

       o   to support obsolete features,

       o   to  reuse functions (for example, those that move the cursor before
           another operation), and

       o   a few special cases.

       If the standard  output  file  descriptor  of  an  ncurses  program  is
       redirected  to  something  that  is  not a terminal device, the library
       writes screen updates to the standard error file descriptor.  This  was
       an undocumented feature of SVr3.

       See  subsection  "Header  files"  below  regarding  symbols  exposed by
       inclusion of curses.h.


       ncurses enables an application  to  capture  mouse  events  on  certain
       terminals, including xterm; see curs_mouse(3x).

       ncurses  provides  a  means of responding to window resizing events, as
       when running in a GUI terminal emulator application such as xterm;  see
       resizeterm(3x) and wresize(3x).

       ncurses allows an application to query the terminal for the presence of
       a wide variety of special keys; see has_key(3x).

       ncurses extends the fixed set of function key capabilities specified by
       X/Open   Curses  by  allowing  the  application  programmer  to  define
       additional   key   sequences   at    runtime;    see    define_key(3x),
       key_defined(3x), and keyok(3x).

       ncurses   can   exploit  the  capabilities  of  terminals  implementing
       ISO 6429/ECMA-48  SGR 39  and  SGR 49   sequences,   which   allow   an
       application  to  reset  the  terminal  to  its  original foreground and
       background colors.  From a user's perspective, the application is  able
       to  draw colored text on a background whose color is set independently,
       providing better control over color contrasts.  See default_colors(3x).

       An ncurses application can choose  to  hide  the  internal  details  of
       WINDOW   structures,   instead   using   accessor   functions  such  as

       ncurses enables an  application  to  direct  application  output  to  a
       printer attached to the terminal device; see curs_print(3x).

       ncurses  offers slk_attr(3x) as a counterpart of attr_get(3x) for soft-
       label key lines, and extended_slk_color(3x) as a form of  slk_color(3x)
       that  can  gather  color  information  from  them  when many colors are

       Some extensions are only available if ncurses is  compiled  to  support
       them; section "ALTERNATE CONFIGURATIONS" describes how.

       o   Rudimentary   support   for   multi-threaded  applications  may  be
           available; see curs_threads(3x).

       o   Functions that ease the  management  of  multiple  screens  can  be
           exposed; see curs_sp_funcs(3x).

       o   To aid applications to debug their memory usage, ncurses optionally
           offers functions to more aggressively free  memory  it  dynamically
           allocates itself; see curs_memleaks(3x).

       o   The   library  facilitates  auditing  and  troubleshooting  of  its
           behavior; see curs_trace(3x).

       o   The compiler option -DUSE_GETCAP causes the library to fall back to
           reading /etc/termcap if the terminal setup code cannot find a term-
           info 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  a  cost  in  memory  usage  and
           application launch latency.

       PDCurses   and  NetBSD  curses  incorporate  some  ncurses  extensions.
       Individual man pages indicate where this is the case.


       X/Open Curses defines two levels of conformance, "base" and "enhanced".
       The latter includes several additional features, such as wide-character
       and color support.  ncurses intends base-level conformance with  X/Open
       Curses, and supports nearly all its enhanced features.

       Differences  between  X/Open  Curses  and ncurses are documented in the
       "PORTABILITY" sections of applicable 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.

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 itself includes the header files  stdio.h  and

       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

           BSD  curses  included  <curses.h>  and  <unctrl.h> from an internal
           header file curses.ext ("ext" abbreviated "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

           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.


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


       curs_variables(3x), terminfo(5), user_caps(5)

ncurses 6.4                       2024-04-13                       ncurses(3x)