ncurses - CRT screen handling and optimization package
SYNOPSIS
#include <curses.h>
DESCRIPTION
The curses library routines give the user a terminal-inde-
pendent method of updating character screens with reason-
able optimization. This implementation is ``new curses''
(ncurses) and is the approved replacement for 4.4BSD clas-
sic curses, which has been discontinued.
The ncurses routines emulate the curses(3X) library of
System V Release 4 UNIX, and the XPG4 curses standard (XSI
curses) but the ncurses library is freely redistributable
in source form. Differences from the SVr4 curses are sum-
marized under the EXTENSIONS and BUGS sections below and
described in detail in the EXTENSIONS and BUGS sections of
individual man pages.
A program using these routines must be linked with the
-lncurses option, or (if it has been generated) with the
debugging library -lncurses_g. (Your system integrator
may also have installed these libraries under the names
-lcurses and -lcurses_g.) The ncurses_g library generates
trace logs (in a file called 'trace' in the current direc-
tory) that describe curses actions.
The ncurses package supports: overall screen, window and
pad manipulation; output to windows and pads; reading ter-
minal input; control over terminal and curses input and
output options; environment query routines; color manipu-
lation; use of soft label keys; terminfo capabilities; and
access to low-level terminal-manipulation routines.
To initialize the routines, the routine initscr or newterm
must be called before any of the other routines that deal
with windows and screens are used. The routine endwin
must be called before exiting. To get character-at-a-time
input without echoing (most interactive, screen oriented
programs want this), the following sequence should be
used:
initscr(); cbreak(); noecho();
Most programs would additionally use the sequence:
nonl();
intrflush(stdscr, FALSE);
keypad(stdscr, TRUE);
Before a curses program is run, the tab stops of the ter-
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 curses library permits manipulation of data struc-
tures, called windows, which can be thought of as two-
dimensional arrays of characters representing all or part
of a CRT screen. A default window called stdscr, which is
the size of the terminal screen, is supplied. Others may
be created with newwin.
Note that curses does not handle overlapping windows,
that's done by the panel(3X) library. This means that you
can either use stdscr or divide the screen into tiled win-
dows and not using stdscr at all. Mixing the two will
result in unpredictable, and undesired, effects.
Windows are referred to by variables declared as WINDOW *.
These data structures are manipulated with routines
described here and elsewhere in the ncurses manual pages.
Among which the most basic routines are move and addch.
More general versions of these routines are included with
names beginning with w, allowing the user to specify a
window. The routines not beginning with w affect stdscr.)
After using routines to manipulate a window, refresh is
called, telling curses to make the user's CRT screen look
like stdscr. The characters in a window are actually of
type chtype, (character and attribute data) so that other
information about the character may also be stored with
each character.
Special windows called pads may also be manipulated.
These are windows which are not constrained to the size of
the screen and whose contents need not be completely dis-
played. See curs_pad(3X) for more information.
In addition to drawing characters on the screen, video
attributes and colors may be supported, causing the char-
acters to show up in such modes as underlined, in reverse
video, or in color on terminals that support such display
enhancements. Line drawing characters may be specified to
be output. On input, curses is also able to translate
arrow and function keys that transmit escape sequences
into single values. The video attributes, line drawing
characters, and input values use names, defined in
<curses.h>, such as A_REVERSE, ACS_HLINE, and KEY_LEFT.
If the environment variables LINES and COLUMNS are set, or
if the program is executing in a window environment, line
and column information in the environment will override
information read by terminfo. This would effect a program
If the environment variable TERMINFO is defined, any pro-
gram using curses checks for a local terminal definition
before checking in the standard place. For example, if
TERM is set to att4424, then the compiled terminal defini-
tion is found in
@DATADIR@/terminfo/a/att4424.
(The a is copied from the first letter of att4424 to avoid
creation of huge directories.) However, if TERMINFO is
set to $HOME/myterms, curses first checks
$HOME/myterms/a/att4424,
and if that fails, it then checks
@DATADIR@/terminfo/a/att4424.
This is useful for developing experimental definitions or
when write permission in @DATADIR@/terminfo is not avail-
able.
The integer variables LINES and COLS are defined in
<curses.h> and will be filled in by initscr with the size
of the screen. The constants TRUE and FALSE have the val-
ues 1 and 0, respectively.
The curses routines also define the WINDOW * variable
curscr which is used for certain low-level operations like
clearing and redrawing a screen containing garbage. The
curscr can be used in only a few routines.
Routine and Argument Names
Many curses routines have two or more versions. The rou-
tines prefixed with w require a window argument. The rou-
tines prefixed with p require a pad argument. Those with-
out a prefix generally use stdscr.
The routines prefixed with mv require a y and x coordinate
to move to before performing the appropriate action. The
mv routines imply a call to move before the call to the
other routine. The coordinate y always refers to the row
(of the window), and x always refers to the column. The
upper left-hand corner is always (0,0), not (1,1).
The routines prefixed with mvw take both a window argument
and x and y coordinates. The window argument is always
specified before the coordinates.
In each case, win is the window affected, and pad is the
Option setting routines require a Boolean flag bf with the
value TRUE or FALSE; bf is always of type bool. The vari-
ables ch and attrs below are always of type chtype. The
types WINDOW, SCREEN, bool, and chtype are defined in
<curses.h>. The type TERMINAL is defined in <term.h>.
All other arguments are integers.
Routine Name Index
The following table lists each curses routine and the name
of the manual page on which it is described. Routines
flagged with `*' are ncurses-specific, not described by
XPG4 or present in SVr4.
center tab(/); l l l l . curses Routine Name/Manual Page
Name = addch/curs_addch(3X) addchnstr/curs_addchstr(3X)
addchstr/curs_addchstr(3X) addnstr/curs_addstr(3X)
addstr/curs_addstr(3X) attroff/curs_attr(3X)
attron/curs_attr(3X) attrset/curs_attr(3X) bau-
drate/curs_termattrs(3X) beep/curs_beep(3X)
bkgd/curs_bkgd(3X) bkgdset/curs_bkgd(3X) border/curs_bor-
der(3X) box/curs_border(3X)
can_change_color/curs_color(3X) cbreak/curs_inopts(3X)
clear/curs_clear(3X) clearok/curs_outopts(3X) clrto-
bot/curs_clear(3X) clrtoeol/curs_clear(3X) color_con-
tent/curs_color(3X) copywin/curs_overlay(3X)
curs_set/curs_kernel(3X) def_prog_mode/curs_kernel(3X)
def_shell_mode/curs_kernel(3X) del_curterm/curs_ter-
minfo(3X) delay_output/curs_util(3X) delch/curs_delch(3X)
deleteln/curs_deleteln(3X) delscreen/curs_initscr(3X) del-
win/curs_window(3X) derwin/curs_window(3X) doup-
date/curs_refresh(3X) dupwin/curs_window(3X)
echo/curs_inopts(3X) echochar/curs_addch(3X) end-
win/curs_initscr(3X) erase/curs_clear(3X)
erasechar/curs_termattrs(3X) filter/curs_util(3X)
flash/curs_beep(3X) flushinp/curs_util(3X) getbe-
gyx/curs_getyx(3X) getch/curs_getch(3X) get-
maxyx/curs_getyx(3X) getmouse/curs_mouse(3X)* get-
paryx/curs_getyx(3X) getstr/curs_getstr(3X) get-
syx/curs_kernel(3X) getwin/curs_util(3X)
getyx/curs_getyx(3X) halfdelay/curs_inopts(3X) has_col-
ors/curs_color(3X) has_ic/curs_termattrs(3X)
has_il/curs_termattrs(3X) has_key/curs_getch(3X)*
hline/curs_border(3X) idcok/curs_outopts(3X)
idlok/curs_outopts(3X) immedok/curs_outopts(3X)
inch/curs_inch(3X) inchnstr/curs_inchstr(3X) inch-
str/curs_inchstr(3X) init_color/curs_color(3X)
init_pair/curs_color(3X) initscr/curs_initscr(3X)
innstr/curs_instr(3X) insch/curs_insch(3X) ins-
delln/curs_deleteln(3X) insertln/curs_deleteln(3X)
insnstr/curs_insstr(3X) insstr/curs_insstr(3X)
isendwin/curs_initscr(3X) keyname/curs_util(3X) key-
pad/curs_inopts(3X) killchar/curs_termattrs(3X)
leaveok/curs_outopts(3X) longname/curs_termattrs(3X)
mcprint/curs_print(3X)* meta/curs_inopts(3X) mouseinter-
val/curs_mouse(3X)* mousemask/curs_mouse(3X)*
move/curs_move(3X) mvaddch/curs_addch(3X) mvaddchn-
str/curs_addchstr(3X) mvaddchstr/curs_addchstr(3X)
mvaddnstr/curs_addstr(3X) mvaddstr/curs_addstr(3X)
mvcur/curs_terminfo(3X) mvdelch/curs_delch(3X) mvder-
win/curs_window(3X) mvgetch/curs_getch(3X) mvget-
str/curs_getstr(3X) mvinch/curs_inch(3X) mvinchn-
str/curs_inchstr(3X) mvinchstr/curs_inchstr(3X)
mvinnstr/curs_instr(3X) mvinsch/curs_insch(3X) mvin-
snstr/curs_insstr(3X) mvinsstr/curs_insstr(3X) mvin-
str/curs_instr(3X) mvprintw/curs_printw(3X) mvs-
canw/curs_scanw(3X) mvwaddch/curs_addch(3X) mvwaddchn-
str/curs_addchstr(3X) mvwaddchstr/curs_addchstr(3X)
mvwaddnstr/curs_addstr(3X) mvwaddstr/curs_addstr(3X)
mvwdelch/curs_delch(3X) mvwgetch/curs_getch(3X) mvwget-
str/curs_getstr(3X) mvwin/curs_window(3X)
mvwinch/curs_inch(3X) mvwinchnstr/curs_inchstr(3X)
mvwinchstr/curs_inchstr(3X) mvwinnstr/curs_instr(3X)
mvwinsch/curs_insch(3X) mvwinsnstr/curs_insstr(3X)
mvwinsstr/curs_insstr(3X) mvwinstr/curs_instr(3X) mvw-
printw/curs_printw(3X) mvwscanw/curs_scanw(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) node-
lay/curs_inopts(3X) noecho/curs_inopts(3X) nonl/curs_out-
opts(3X) noqiflush/curs_inopts(3X) noraw/curs_inopts(3X)
notimeout/curs_inopts(3X) overlay/curs_overlay(3X) over-
write/curs_overlay(3X) pair_content/curs_color(3X)
pechochar/curs_pad(3X) pnoutrefresh/curs_pad(3X) pre-
fresh/curs_pad(3X) printw/curs_printw(3X) putp/curs_ter-
minfo(3X) putwin/curs_util(3X) qiflush/curs_inopts(3X)
raw/curs_inopts(3X) redrawwin/curs_refresh(3X)
refresh/curs_refresh(3X) reset_prog_mode/curs_kernel(3X)
reset_shell_mode/curs_kernel(3X) resetty/curs_kernel(3X)
resizeterm/resizeterm(3X)* restartterm/curs_terminfo(3X)
ripoffline/curs_kernel(3X) savetty/curs_kernel(3X)
scanw/curs_scanw(3X) scr_dump/curs_scr_dump(3X)
scr_init/curs_scr_dump(3X) scr_restore/curs_scr_dump(3X)
scr_set/curs_scr_dump(3X) scrl/curs_scroll(3X)
scroll/curs_scroll(3X) scrollok/curs_outopts(3X)
set_curterm/curs_terminfo(3X) set_term/curs_initscr(3X)
setscrreg/curs_outopts(3X) setsyx/curs_kernel(3X) set-
term/curs_terminfo(3X) setupterm/curs_terminfo(3X)
slk_attr/curs_slk(3X)* slk_attroff/curs_slk(3X)
slk_attron/curs_slk(3X) slk_attrset/curs_slk(3X)
slk_clear/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)
start_color/curs_color(3X) subpad/curs_pad(3X) sub-
win/curs_window(3X) syncok/curs_window(3X) termat-
trs/curs_termattrs(3X) termname/curs_termattrs(3X) tge-
tent/curs_termcap(3X) tgetflag/curs_termcap(3X) tget-
num/curs_termcap(3X) tgetstr/curs_termcap(3X)
tgoto/curs_termcap(3X) tigetflag/curs_terminfo(3X) tiget-
num/curs_terminfo(3X) tigetstr/curs_terminfo(3X) time-
out/curs_inopts(3X) touchline/curs_touch(3X) touch-
win/curs_touch(3X) tparm/curs_terminfo(3X)
tputs/curs_termcap(3X) tputs/curs_terminfo(3X) typea-
head/curs_inopts(3X) unctrl/curs_util(3X)
ungetch/curs_getch(3X) ungetmouse/curs_mouse(3X)* untouch-
win/curs_touch(3X) use_env/curs_util(3X) vidattr/curs_ter-
minfo(3X) vidputs/curs_terminfo(3X) vline/curs_border(3X)
vwprintw/curs_printw(3X) vwscanw/curs_scanw(3X) wad-
dch/curs_addch(3X) waddchnstr/curs_addchstr(3X) waddch-
str/curs_addchstr(3X) waddnstr/curs_addstr(3X)
waddstr/curs_addstr(3X) wattroff/curs_attr(3X) wat-
tron/curs_attr(3X) wattrset/curs_attr(3X)
wbkgd/curs_bkgd(3X) wbkgdset/curs_bkgd(3X) wbor-
der/curs_border(3X) wclear/curs_clear(3X) wclrto-
bot/curs_clear(3X) wclrtoeol/curs_clear(3X) wcursyn-
cup/curs_window(3X) wdelch/curs_delch(3X)
wdeleteln/curs_deleteln(3X) wechochar/curs_addch(3X) wen-
close/curs_mouse(3X)* werase/curs_clear(3X)
wgetch/curs_getch(3X) wgetnstr/curs_getstr(3X) wget-
str/curs_getstr(3X) whline/curs_border(3X)
winch/curs_inch(3X) winchnstr/curs_inchstr(3X) winch-
str/curs_inchstr(3X) winnstr/curs_instr(3X) win-
sch/curs_insch(3X) winsdelln/curs_deleteln(3X) win-
sertln/curs_deleteln(3X) winsnstr/curs_insstr(3X)
winsstr/curs_insstr(3X) winstr/curs_instr(3X)
wmove/curs_move(3X) wnoutrefresh/curs_refresh(3X)
wprintw/curs_printw(3X) wredrawln/curs_refresh(3X) wre-
fresh/curs_refresh(3X) wresize/wresize(3X)*
wscanw/curs_scanw(3X) wscrl/curs_scroll(3X) wsetscr-
reg/curs_outopts(3X) wstandend/curs_attr(3X) wstand-
out/curs_attr(3X) wsyncdown/curs_window(3X) wsyn-
cup/curs_window(3X) wtimeout/curs_inopts(3X)
wtouchln/curs_touch(3X) wvline/curs_border(3X)
RETURN VALUE
Routines that return an integer return ERR upon failure
and an integer value other than ERR upon successful com-
pletion, unless otherwise noted in the routine descrip-
tions.
All macros return the value of the w version, except
setscrreg, wsetscrreg, getyx, getbegyx, getmaxyx. The
return values of setscrreg, wsetscrreg, getyx, getbegyx,
and getmaxyx are undefined (i.e., these should not be used
as the right-hand side of assignment statements).
SEE ALSO
terminfo(5) and 3X pages whose names begin "curs_" for
detailed routine descriptions.
EXTENSIONS
The curses library can be compiled with an option (-DTERM-
CAP_FILE) that falls back to the old-style /etc/termcap
file if the terminal setup code cannot find a terminfo
entry corresponding to TERM. Use of this feature is not
recommended, as it essentially includes an entire termcap
compiler in the curses startup code, at significant cost
in core and startup cycles.
Compiling with -DTERMCAP_FILE changes the library's ini-
tialization sequence in a way intended to mimic the behav-
ior of 4.4BSD curses. If there is no local or system ter-
minfo entry matching TERM, then the library looks for
termcap entries in the following places: (1) if TERMINFO
is undefined, in the file named by TERMCAP_FILE; (2) if
TERMINFO is defined and begins with a slash, it is inter-
preted as the name of a termcap file to search for TERM;
(3) otherwise, if TERMINFO has a leading string that looks
like a terminal entry name list, and it matches TERM, the
contents of TERMINFO is interpreted as a termcap; (4) if
TERMINFO looks like a termcap but doesn't match TERM, the
termcap file is searched for among the colon-separated
paths in the environment variable TERMPATHS if that is
defined, and in ~/.termcap and the file value of TERM-
CAP_FILE otherwise.
Versions of curses compiled on PC clones support display
of the PC ROM characters (including ROM characters 0-31,
which stock SVr4 curses cannot display). See the EXTEN-
SIONS sections of curs_addch(3X) and curs_attr(3X).
The curses library includes facilities for capturing mouse
events on certain terminals (including xterm). See the
curs_mouse(3X) manual page for details.
The curses library includes a function for directing
application output to a printer attached to the terminal
device. See the curs_print(3X) manual page for details.
PORTABILITY
The curses library is intended to be BASE-level conformant
with the XSI Curses standard. Certain portions of the
EXTENDED XSI Curses functionality (including color sup-
port) are supported. The following EXTENDED XSI Curses
calls in support of wide (multibyte) characters are not
yet implemented: addnwstr, addwstr, mvaddnwstr, mvwaddnw-
str, mvaddwstr, waddnwstr, waddwstr, add_wch, wadd_wch,
mvwadd_wchnstr, mvwadd_wchstr, bkgrndset, bkgrnd, get-
bkgrnd, wbkgrnd, wbkgrndset, wgetbkgrnd, border_set, wbor-
der_set, box_set, hline_set, mvhline_set, mvvline_set,
mvwhline_set, mvwvline_set, whline_set, vhline_set,
wvline_set, echo_wchar, wecho_wchar, erasewchar, kill-
wchar, get_wch, mvget_wch, mvwget_ch, wget_wch,
getwchtype, get_wstr, getn_wstr, wget_wstr, wgetn_wstr,
mvget_wstr, mvgetn_wstr, mvwget_wstr, mvwgetn_wstr, innw-
str, inwstr, winnwstr, winwstr, mvinnwstr, mvinwstr,
mvwinnwstr, mvwinwstr, ins_nwstr, ins_wstr, mvins_nwstr,
mvins_wstr, mvwins_nwstr, mvwins_wstr, wins_nwstr,
wins_wstr, ins_wch, wins_wch, mvins_wch, mvwins_wch,
in_wch, win_wch, mvin_wch, mvwin_wch, inwchstr, inwchnstr,
winwchstr, winwchnstr, mvinwchstr, mvinwchnstr, mvinwch-
str, mvwinwchnstr.
A small number of local differences (that is, individual
differences between the XSI Curses and curses calls) are
described in PORTABILITY sections of the library man
pages.
The routine has_key is not part of XPG4, nor is it present
in SVr4. See the curs_getch(3X) manual page for details.
The routine slk_attr is not part of XPG4, nor is it pre-
sent in SVr4. See the curs_slk(3X) manual page for
details.
The routines getmouse, mousemask, ungetmouse, mouseinter-
val, and wenclose relating to mouse interfacing are not
part of XPG4, nor are they present in SVr4. See the
curs_mouse(3X) manual page for details.
The routine mcprint was not present in any previous curses
implementation. See the curs_print(3X) manual page for
details.
The routine wresize is not part of XPG4, nor is it present
in SVr4. See the wresize(3X) manual page for details.
In historic curses versions, delays embedded in the capa-
bilities cr, ind, cub1, ff and tab activated corresponding
delay bits in the UNIX tty driver. In this implementa-
tion, all padding is done by NUL sends. This method is
slightly more expensive, but narrows the interface to the
UNIX kernel significantly and increases the package's
portability correspondingly.
In the XSI standard and SVr4 manual pages, many entry
points have prototype arguments of the for char *const (or
cchar_t *const, or wchar_t *const, or void *const).
Depending on one's interpretation of the ANSI C standard
tion const char *x is a modifiable pointer to unmodifiable
data, but char *const x' is an unmodifiable pointer to
modifiable data. Given that C passes arguments by value,
<type> *const as a formal type is at best dubious. Some
compilers choke on the prototypes. Therefore, in this
implementation, they have been changed to const <type> *
globally.
NOTES
The header file <curses.h> automatically includes the
header files <stdio.h> and <unctrl.h>.
If standard output from a curses program is re-directed to
something which is not a tty, screen updates will be
directed to standard error. This was an undocumented fea-
ture of AT&T System V Release 3 curses.
AUTHORS
Zeyd M. Ben-Halim, Eric S. Raymond. Descends from the
original pcurses by Pavel Curtis.