ncurses
ncurses(3X) ncurses(3X)
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.
The ncurses routines emulate the curses(3X) library of System V
Release 4 UNIX, and the XPG4 curses standard (XSI curses) but the
ncurses library is freely redistributable in source form. Differences
from the SVr4 curses are summarized under the EXTENSIONS and BUGS sec-
tions below and described in detail in the EXTENSIONS and BUGS sec-
tions of individual man pages.
A program using these routines must be linked with the -lncurses
option, or (if it has been generated) with the debugging library
-lncurses_g. (Your system integrator may also have installed these
libraries under the names -lcurses and -lcurses_g.) The ncurses_g
library generates trace logs (in a file called ’trace’ in the current
directory) that describe curses actions.
The ncurses package supports: overall screen, window and pad manipula-
tion; output to windows and pads; reading terminal input; control over
terminal and curses input and output options; environment query rou-
tines; color manipulation; use of soft label keys; terminfo capabili-
ties; and access to low-level terminal-manipulation routines.
To initialize the routines, the routine initscr or newterm must be
called before any of the other routines that deal with windows and
screens are used. The routine endwin must be called before exiting.
To get character-at-a-time input without echoing (most interactive,
screen oriented programs want this), the following sequence should be
used:
initscr(); cbreak(); noecho();
Most programs would additionally use the sequence:
nonl();
intrflush(stdscr, FALSE);
keypad(stdscr, TRUE);
Before a curses program is run, the tab stops of the 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.]
The ncurses library permits manipulation of data structures, called
windows, which can be thought of as two-dimensional arrays of charac-
ters representing all or part of a CRT screen. A default window
called stdscr, which is the size of the terminal screen, is supplied.
Others may be created with newwin.
Note that curses does not handle overlapping windows, that’s done by
the panel(3X) library. This means that you can either use stdscr or
divide the screen into tiled windows and not using stdscr at all.
Mixing the two will result in unpredictable, and undesired, effects.
Windows are referred to by variables declared as WINDOW *. These data
structures are manipulated with routines described here and elsewhere
in the ncurses manual pages. Among which the most basic routines are
move and addch. More general versions of these routines are included
with names beginning with w, allowing the user to specify a window.
The routines not beginning with w affect stdscr.)
After using routines to manipulate a window, refresh is called,
telling curses to make the user’s CRT screen look like stdscr. The
characters in a window are actually of type chtype, (character and
attribute data) so that other information about the character may also
be stored with each character.
Special windows called pads may also be manipulated. These are win-
dows 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 val-
ues use names, defined in <curses.h>, such as A_REVERSE, ACS_HLINE,
and KEY_LEFT.
If the environment variables LINES and COLUMNS are set, or if the pro-
gram is executing in a window environment, line and column information
in the environment will override information read by terminfo. This
would effect a program running in an AT&T 630 layer, for example,
where the size of a screen is changeable (see ENVIRONMENT).
If the environment variable TERMINFO is defined, any program using
curses checks for a local terminal definition before checking in the
standard place. For example, if TERM is set to att4424, then the com-
piled terminal definition is found in
/usr/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
/usr/share/terminfo/a/att4424.
This is useful for developing experimental definitions or when write
permission in /usr/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 con-
stants TRUE and FALSE have the values 1 and 0, respectively.
The curses routines also define the WINDOW * variable curscr which is
used for certain low-level operations like clearing and redrawing a
screen containing garbage. The curscr can be used in only a few rou-
tines.
Routine and Argument Names
Many curses routines have two or more versions. The routines prefixed
with w require a window argument. The routines prefixed with p
require a pad argument. Those without a prefix generally use stdscr.
The routines prefixed with mv require a y and x coordinate to move to
before performing the appropriate action. The mv routines imply a
call to move before the call to the other routine. The coordinate y
always refers to the row (of the window), and x always refers to the
column. The upper left-hand corner is always (0,0), not (1,1).
The routines prefixed with mvw take both a window argument and x and y
coordinates. The window argument is always specified before the coor-
dinates.
In each case, win is the window affected, and pad is the pad affected;
win and pad are always pointers to type WINDOW.
Option setting routines require a Boolean flag bf with the value TRUE
or FALSE; bf is always of type bool. The variables ch and attrs below
are always of type chtype. The types WINDOW, SCREEN, bool, and chtype
are defined in <curses.h>. The type TERMINAL is defined in <term.h>.
All other arguments are integers.
Routine Name Index
The following table lists each curses routine and the name of the man-
ual page on which it is described. Routines flagged with ‘*’ are
ncurses-specific, not described by XPG4 or present in SVr4.
curses Routine Name Manual Page Name
--------------------------------------------
COLOR_PAIR curs_color(3X)
PAIR_NUMBER curs_attr(3X)
_nc_tracebits curs_trace(3X)*
_traceattr curs_trace(3X)*
_traceattr2 curs_trace(3X)*
_tracechar curs_trace(3X)*
_tracechtype curs_trace(3X)*
_tracechtype2 curs_trace(3X)*
_tracedump curs_trace(3X)*
_tracef curs_trace(3X)*
_tracemouse curs_trace(3X)*
add_wch curs_add_wch(3X)
add_wchnstr curs_add_wchstr(3X)
add_wchstr curs_add_wchstr(3X)
addch curs_addch(3X)
addchnstr curs_addchstr(3X)
addchstr curs_addchstr(3X)
addnstr curs_addstr(3X)
addnwstr curs_addwstr(3X)
addstr curs_addstr(3X)
addwstr curs_addwstr(3X)
assume_default_colors default_colors(3X)*
attr_get curs_attr(3X)
attr_off curs_attr(3X)
attr_on curs_attr(3X)
attr_set curs_attr(3X)
attroff curs_attr(3X)
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_version curs_extend(3X)*
def_prog_mode curs_kernel(3X)
def_shell_mode curs_kernel(3X)
define_key define_key(3X)*
del_curterm curs_terminfo(3X)
delay_output curs_util(3X)
delch curs_delch(3X)
deleteln curs_deleteln(3X)
delscreen curs_initscr(3X)
delwin curs_window(3X)
derwin curs_window(3X)
doupdate curs_refresh(3X)
dupwin curs_window(3X)
echo curs_inopts(3X)
echo_wchar curs_add_wch(3X)
echochar curs_addch(3X)
endwin curs_initscr(3X)
erase curs_clear(3X)
erasechar curs_termattrs(3X)
erasewchar curs_termattrs(3X)
filter curs_util(3X)
flash curs_beep(3X)
flushinp curs_util(3X)
get_wch curs_get_wch(3X)
get_wstr curs_get_wstr(3X)
getbegyx curs_getyx(3X)
getbkgd curs_bkgd(3X)
getbkgrnd curs_bkgrnd(3X)
getcchar curs_getcchar(3X)
getch curs_getch(3X)
getmaxyx curs_getyx(3X)
getmouse curs_mouse(3X)*
getn_wstr curs_get_wstr(3X)
getnstr curs_getstr(3X)
getparyx curs_getyx(3X)
getstr curs_getstr(3X)
getsyx curs_kernel(3X)
getwin curs_util(3X)
getyx curs_getyx(3X)
halfdelay curs_inopts(3X)
has_colors curs_color(3X)
has_ic curs_termattrs(3X)
has_il curs_termattrs(3X)
has_key curs_getch(3X)*
hline curs_border(3X)
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_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_linetouched curs_touch(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_outopts(3X)
nocbreak curs_inopts(3X)
nodelay curs_inopts(3X)
noecho curs_inopts(3X)
nonl curs_outopts(3X)
noqiflush curs_inopts(3X)
noraw curs_inopts(3X)
notimeout curs_inopts(3X)
overlay curs_overlay(3X)
overwrite curs_overlay(3X)
pair_content curs_color(3X)
pechochar curs_pad(3X)
pnoutrefresh curs_pad(3X)
prefresh curs_pad(3X)
printw curs_printw(3X)
putp curs_terminfo(3X)
putwin curs_util(3X)
qiflush curs_inopts(3X)
raw curs_inopts(3X)
redrawwin curs_refresh(3X)
refresh curs_refresh(3X)
reset_prog_mode curs_kernel(3X)
reset_shell_mode curs_kernel(3X)
resetty curs_kernel(3X)
resizeterm resizeterm(3X)*
restartterm curs_terminfo(3X)
ripoffline curs_kernel(3X)
savetty curs_kernel(3X)
scanw curs_scanw(3X)
scr_dump curs_scr_dump(3X)
scr_init curs_scr_dump(3X)
scr_restore curs_scr_dump(3X)
scr_set curs_scr_dump(3X)
scrl curs_scroll(3X)
scroll curs_scroll(3X)
scrollok curs_outopts(3X)
set_curterm curs_terminfo(3X)
set_term curs_initscr(3X)
setcchar curs_getcchar(3X)
setscrreg curs_outopts(3X)
setsyx curs_kernel(3X)
setterm curs_terminfo(3X)
setupterm curs_terminfo(3X)
slk_attr curs_slk(3X)*
slk_attr_off curs_slk(3X)
slk_attr_on curs_slk(3X)
slk_attr_set curs_slk(3X)
slk_attroff curs_slk(3X)
slk_attron curs_slk(3X)
slk_attrset curs_slk(3X)
slk_clear curs_slk(3X)
slk_color curs_slk(3X)
slk_init curs_slk(3X)
slk_label curs_slk(3X)
slk_noutrefresh curs_slk(3X)
slk_refresh curs_slk(3X)
slk_restore curs_slk(3X)
slk_set curs_slk(3X)
slk_touch curs_slk(3X)
standend curs_attr(3X)
standout curs_attr(3X)
start_color curs_color(3X)
subpad curs_pad(3X)
subwin curs_window(3X)
syncok curs_window(3X)
term_attrs curs_termattrs(3X)
termattrs curs_termattrs(3X)
termname curs_termattrs(3X)
tgetent curs_termcap(3X)
tgetflag curs_termcap(3X)
tgetnum curs_termcap(3X)
tgetstr curs_termcap(3X)
tgoto curs_termcap(3X)
tigetflag curs_terminfo(3X)
tigetnum curs_terminfo(3X)
tigetstr curs_terminfo(3X)
timeout curs_inopts(3X)
touchline curs_touch(3X)
touchwin curs_touch(3X)
tparm curs_terminfo(3X)
tputs curs_termcap(3X)
tputs curs_terminfo(3X)
trace curs_trace(3X)*
typeahead curs_inopts(3X)
unctrl curs_util(3X)
unget_wch curs_get_wch(3X)
ungetch curs_getch(3X)
ungetmouse curs_mouse(3X)*
untouchwin curs_touch(3X)
use_default_colors default_colors(3X)*
use_env curs_util(3X)
use_extended_names curs_extend(3X)*
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)
wgetn_wstr curs_get_wstr(3X)
wgetnstr curs_getstr(3X)
wgetstr curs_getstr(3X)
whline curs_border(3X)
whline_set curs_border_set(3X)
win_wch curs_in_wch(3X)
win_wchnstr curs_in_wchstr(3X)
win_wchstr curs_in_wchstr(3X)
winch curs_inch(3X)
winchnstr curs_inchstr(3X)
winchstr curs_inchstr(3X)
winnstr curs_instr(3X)
winnwstr curs_inwstr(3X)
wins_nwstr curs_ins_wstr(3X)
wins_wch curs_ins_wch(3X)
wins_wstr curs_ins_wstr(3X)
winsch curs_insch(3X)
winsdelln curs_deleteln(3X)
winsertln curs_deleteln(3X)
winsnstr curs_insstr(3X)
winsstr curs_insstr(3X)
winstr curs_instr(3X)
winwstr curs_inwstr(3X)
wmouse_trafo curs_mouse(3X)*
wmove curs_move(3X)
wnoutrefresh curs_refresh(3X)
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)
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.
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).
Routines that return pointers return NULL on error.
ENVIRONMENT
The following environment symbols are useful for customizing the run-
time behavior of the ncurses library. The most important ones have
been already discussed in detail.
BAUDRATE
The debugging library checks this environment symbol when the
application has redirected output to a file. The symbol’s
numeric value is used for the baudrate. If no value is found,
ncurses uses 9600. This allows testers to construct repeatable
test-cases that take into account costs that depend on baudrate.
CC When set, change occurrences of the command_character (i.e., the
cmdch capability) of the loaded terminfo entries to the value of
this symbol. Very few terminfo entries provide this feature.
COLUMNS
Specify the width of the screen in characters. Applications run-
ning in a windowing environment usually are able to obtain the
width of the window in which they are executing. If neither the
$COLUMNS value nor the terminal’s screen size is available,
ncurses uses the size which may be specified in the terminfo
database (i.e., the cols capability).
It is important that your application use a correct size for the
screen. However, this is not always possible because your appli-
cation may be running on a host which does not honor NAWS (Nego-
tiations About Window Size), or because you are temporarily run-
ning as another user.
Either COLUMNS or LINES symbols may be specified independently.
This is mainly useful to circumvent legacy misfeatures of termi-
nal 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 emula-
tions.
Use the use_env function to disable this feature.
ESCDELAY
Specifies the total time, in milliseconds, for which ncurses will
await a character sequence, e.g., a function key. The default
value, 1000 milliseconds, is enough for most uses. However, it
is made a 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.
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 inconsis-
tently from other platforms:
1 = left
2 = right
3 = middle.
This symbol lets you customize the mouse. The symbol must be
three numeric digits 1-3 in any order, e.g., 123 or 321. If it
is not specified, ncurses uses 132.
NCURSES_ASSUMED_COLORS
Override the compiled-in assumption that the terminal’s default
colors are white-on-black (see assume_default_colors(3X)). You
may set the foreground and background color values with this
environment variable by proving a 2-element list: fore-
ground,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_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 termi-
nal 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 descrip-
tions, but not want to pay the performance penalty.
Set the NCURSES_NO_PADDING symbol to disable all but mandatory
padding. Mandatory padding is used as a part of special control
sequences such as flash.
NCURSES_NO_SETBUF
Normally ncurses enables buffered output during terminal initial-
ization. This is done (as in SVr4 curses) for performance rea-
sons. For testing purposes, both of ncurses and certain applica-
tions, this feature is made optional. Setting the
NCURSES_NO_SETBUF variable disables output buffering, leaving the
output in the original (usually line buffered) mode.
NCURSES_TRACE
During initialization, the ncurses debugging library checks the
NCURSES_TRACE symbol. If it is defined, to a numeric value,
ncurses calls the trace function, using that value as the argu-
ment.
The argument values, which are defined in curses.h, provide sev-
eral types of information. When running with traces enabled,
your application will write the file trace to the current direc-
tory.
TERM Denotes your terminal type. Each terminal type is distinct,
though many are similar.
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 symbol contains either a terminal description (with
newlines stripped out), or a file name telling where the informa-
tion denoted by the TERM symbol exists. In either case, setting
it directs ncurses to ignore the usual place for this informa-
tion, e.g., /etc/termcap.
TERMINFO
Overrides the directory in which ncurses searches for your termi-
nal description. This is the simplest, but not the only way to
change the list of directories. The complete list of directories
in order follows:
- the last directory to which ncurses wrote, if any, is searched
first
- the directory specified by the TERMINFO symbol
- $HOME/.terminfo
- directories listed in the TERMINFO_DIRS symbol
- one or more directories whose names are configured and com-
piled into the ncurses library, e.g., /usr/share/terminfo
TERMINFO_DIRS
Specifies a list of directories to search for terminal descrip-
tions. The list is separated by colons (i.e., ":") on Unix,
semicolons on OS/2 EMX. All of the terminal descriptions are in
terminfo form, which makes a subdirectory named for the first
letter of the terminal names therein.
TERMPATH
If TERMCAP does not hold a file name then ncurses checks the
TERMPATH symbol. This is a list of filenames separated by spaces
or colons (i.e., ":") on Unix, semicolons on OS/2 EMX. If the
TERMPATH symbol is not set, ncurses looks in the files /etc/term-
cap, /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.
FILES
/usr/share/tabset
directory containing initialization files for the terminal capa-
bility database /usr/share/terminfo terminal capability database
SEE ALSO
terminfo(5) and related pages whose names begin "curs_" for detailed
routine descriptions.
EXTENSIONS
The ncurses library can be compiled with an option (-DUSE_GETCAP) that
falls back to the old-style /etc/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 term-
cap 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 back-
ground colors. From the users’ perspective, the application is able
to draw colored text on a background whose color is set independently,
providing better control over color contrasts. See the default_col-
ors(3X) manual page for details.
The ncurses library includes a function for directing application out-
put to a printer attached to the terminal device. See the
curs_print(3X) manual page for details.
PORTABILITY
The ncurses library is intended to be BASE-level conformant with the
XSI Curses standard. 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.
The routine has_key is not part of XPG4, nor is it present in SVr4.
See the curs_getch(3X) manual page for details.
The routine slk_attr is not part of XPG4, nor is it present in SVr4.
See the curs_slk(3X) manual page for details.
The routines getmouse, mousemask, ungetmouse, mouseinterval, and wen-
close relating to mouse interfacing are not part of XPG4, nor are they
present in SVr4. See the curs_mouse(3X) manual page for details.
The routine mcprint was not present in any previous curses implementa-
tion. See the curs_print(3X) manual page for details.
The routine wresize is not part of XPG4, nor is it present in SVr4.
See the wresize(3X) manual page for details.
In historic curses versions, delays embedded in the capabilities cr,
ind, cub1, ff and tab activated corresponding delay bits in the UNIX
tty driver. In this implementation, all padding is done by NUL sends.
This method is slightly more expensive, but narrows the interface to
the UNIX kernel significantly and increases the package’s portability
correspondingly.
NOTES
The header file <curses.h> automatically includes the header files
<stdio.h> and <unctrl.h>.
If standard output from a ncurses program is re-directed to something
which is not a tty, screen updates will be directed to standard error.
This was an undocumented 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(3X)
