|
HTML rendering created 2026-01-16 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ENVIRONMENT | ALTERNATE CONFIGURATIONS | FILES | NOTES | EXTENSIONS | PORTABILITY | AUTHORS | SEE ALSO | COLOPHON |
|
|
|
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 writing
to character-cell displays 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 document describes ncurses
version @NCURSES_MAJOR@.@NCURSES_MINOR@ (patch @NCURSES_PATCH@).
ncurses permits control of the terminal screen's contents;
abstraction and subdivision thereof with windows and pads;
acquisition of keyboard and mouse events; selection of color and
rendering attributes (such as bold or underline); the definition
and use of soft label keys; access to the terminfo terminal
capability database; a termcap compatibility interface; and an
abstraction of the system's API for manipulating the terminal
(such as termios(3)).
ncurses implements the 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.
• “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 of significance to the
programmer but which are not standardized.
• “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 state.
• “PORTABILITY” discusses matters (beyond the exercise of
extensions) that should be considered when writing to a curses
standard, or for multiple implementations.
• “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 logs events
describing ncurses actions to a file called trace in the
application's working directory at startup. See section
“ALTERNATE CONFIGURATIONS” below.
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 access or manipulate windows or
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 would perform further setup as follows.
noqiflush();
keypad(stdscr, TRUE);
A curses program then often enters an event-handling loop. Call
endwin(3X) before exiting.
Overview
A curses library abstracts the terminal with a SCREEN data
structure, and represents all or part of its display with WINDOW
structures. Distinct properties apply to each; for example, the
line discipline of a typical Unix terminal driver is in one of
three modes: raw, cbreak, or canonical (“cooked”). In curses, the
line discipline is a property of the screen, applying identically
to all windows associated with it.
A window is a rectangular grid of character cells, addressed by
line and column coordinates (y, x), with the upper left corner as
(0, 0). A window called stdscr, by default the same size as the
terminal screen, is always available. Create others with
newwin(3X).
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 effects.
Functions permit manipulation of a window and the cursor
identifying the cell within it at which the next operation will
occur. Among those, the most basic are move(3X) and addch(3X):
these place the cursor within 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 as a rule the library does not 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 volume 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
not constrained to the size of the terminal screen and their
contents need not be completely displayed. See curs_pad(3X).
Many terminals support configuration of character cell foreground
and background colors as well as attributes, which cause
characters to render in such modes as boldfaced, underlined, or in
reverse video. See curs_color(3X) and curs_attr(3X).
curses defines constants to simplify access to a small set of
forms-drawing graphics corresponding to the DEC Alternate
Character Set (ACS), a feature of VT100 and other terminals. See
addch(3X).
curses is implemented using the operating system's terminal
driver; key events are received not as scan codes but as byte
sequences. The driver reports graphical keycaps (alphanumeric and
punctuation keys, and the space) as-is. Everything else,
including the tab, enter/return, keypad, arrow, and function keys,
appears to curses as a control character or a multibyte escape
sequence. curses can translate the latter into unique key codes.
See keypad(3X) and getch(3X).
ncurses provides reimplementations of the SVr4 panel(3X),
form(3X), and menu(3X) libraries; they permit overlapping windows
and ease construction of user interfaces with curses.
Initialization
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
situations.
If you change the terminal type from a shell, export TERM, 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 term‐
info. An ncurses extension supports resizable terminal displays;
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 type descriptions
or when write permission to terminfo is not available.
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; see
below.
In function synopses, ncurses man pages apply the following names
to parameters. We introduce the character types in the next
subsection.
bf a bool (TRUE or FALSE)
c a char or int
ch a chtype
wc a wchar_t or wint_t
wch a cchar_t
win pointer to a WINDOW
pad pointer to a WINDOW that is a pad
pair a foreground/background color pair identifier
Wide and Non-wide Character Configurations
This man page primarily surveys functions that appear in any
configuration of the library. There are two common
configurations; for others, see section “ALTERNATE CONFIGURATIONS”
below.
ncurses
is the library in its “non-wide” configuration, handling
only eight-bit characters. It stores a character combined
with attributes and a color pair identifier in a chtype
datum, which is often an alias of int. A string of curses
characters is similar to a C char string; a chtype string
ends with an integral 0, the null curses character.
Attributes and a color pair identifier (with no
corresponding character) can be stored in variables of
chtype or attr_t type. In either case, they are accessed
via an integral bit mask.
ncurses stores each cell of a WINDOW as a chtype. X/Open
Curses does not specify the sizes of the character code or
color pair identifier, nor the quantity of attribute bits,
in chtype; these are implementation-dependent. ncurses
uses eight bits for the character code. An application
requiring a wider character type, for instance to represent
Unicode, should use the wide-character API.
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 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. An exception is
ins_nwstr (and its variants), spelled thus instead of
“insn_wstr”. (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
“attr_on”.
cchar_t
is a curses complex character and corresponds to
the non-wide-character configuration's chtype.
It is a structure type because it requires more
storage than a standard scalar type offers. 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). A string of complex characters ends
with a cchar_t whose wchar_t member is the null
wide character. Attributes and a color pair
identifier are stored in separate fields of the
structure, not combined into an integer as in
chtype.
ncurses stores each cell of a WINDOW 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.
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_kernel(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
curs_sp_funcs(3X).
The availability of some extensions is configurable when ncurses
is compiled; see sections “ALTERNATE CONFIGURATIONS” and
“EXTENSIONS” below.
Unless otherwise noted, functions that return integers return the
constants OK on success and ERR on failure; see
curs_variables(3X). Functions that return pointers return a null
pointer on failure. Typically, ncurses treats a null pointer
passed as a function parameter as a failure. Functions prefixed
with “mv” first perform cursor movement and fail if the position
(y, x) is outside the window boundaries.
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).
BAUDRATE
The debugging library checks this variable when the application
has redirected output to a file. ncurses interprets its integral
value as the terminal's line speed in bits per second. If that
value is absent or invalid, ncurses uses 9600. This feature
allows developers to construct repeatable test cases that take
into account optimization decisions that depend on the terminal's
line speed.
[1mCC[24m (command character)
When set, the command_character (cmdch) capability value of loaded
terminfo entries changes to the value of this variable. Very few
terminfo entries provide this feature.
Because this name is also used in development environments to
store the C compiler's name, ncurses ignores its value if it is
not one character in length.
COLUMNS
This variable specifies the width of the screen in character
cells. Applications running in a windowing environment usually
are able to obtain the width of the window in which they are
executing. ncurses enforces an upper limit of 512 when reading
the value. 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 any.
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.
ESCDELAY
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;
ncurses enforces an upper limit of 30,000 (30 seconds) when
reading the value.
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. Conversely, a
fast typist on a low-latency connection who happens to input an
ESC followed by characters that match an escape sequence may
experience confusing application behavior.
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,
ESCDELAY is irrelevant and a program must disambiguate escape
sequences itself.
HOME
ncurses may read and write auxiliary terminal descriptions in
.termcap and .terminfo files in the user's home directory.
LINES
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.
MOUSE_BUTTONS_123
(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”.
NCURSES_ASSUMED_COLORS
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 on a terminal that uses ANSI X3.64/ECMA-48/ISO 6429
color assignments, use “2,0”. ncurses accepts integral values
from -1 up to the value of the terminfo max_colors (colors)
capability for the selected terminal type.
NCURSES_CONSOLE2
(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.
NCURSES_GPM_TERMS
(Linux only) When ncurses is configured to use the GPM interface,
this variable may list one or more terminal type names, delimited
by vertical bars (|) or colons (:), 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_NO_HARD_TABS
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.
NCURSES_NO_MAGIC_COOKIE
Many terminals store video attributes as properties of a character
cell, as curses does. Historically, some recorded changes in
video attributes as data that logically (but invisibly) occupied
character cells on the display, switching attributes on or off,
similarly to tags in a markup language, which then had to be
overprinted to depict the cells' desired contents; these are
termed “magic cookies”. 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.
NCURSES_NO_PADDING
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 itself to prevent overruns and data loss.
A solution that comes at no hardware cost is for an application to
pause transmission 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 terminal 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).
NCURSES_NO_SETBUF
(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 the library's handling of
keyboard-initiated signals 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 not.
NCURSES_NO_UTF8_ACS
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.
NCURSES_TRACE
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.
TERM
The TERM variable denotes the terminal type. Each is distinct,
though many are similar. It is commonly set by terminal emulators
to help applications find a workable terminal description. Some
choose a popular approximation such as “ansi”, “vt100”, or “xterm”
rather than an exact fit to their capabilities. Not infrequently,
an application will have problems with that approach; for example,
a key stroke may not operate correctly, or produce no effect but
seeming garbage characters on the screen.
Setting TERM has no effect on hardware operation; it affects the
way applications communicate with the terminal. Likewise, as a
general rule (xterm(1) being a rare exception), terminal emulators
that allow you to specify TERM as a parameter or configuration
value do not change their behavior to match that setting.
TERMCAP
If ncurses is configured with termcap support, it checks for a
terminal type description in termcap format if one in terminfo
format is not available. Setting this variable directs ncurses to
ignore the usual termcap database location, /etc/termcap; see
TERMPATH below. TERMCAP should contain either a terminal
description (with newlines stripped out), or a file name
indicating where the information required by the TERM environment
variable is stored.
TERMINFO
ncurses can be configured to read terminal type description
databases in various locations using different formats. This
variable overrides the default location.
• Descriptions in terminfo format are normally stored in a
directory tree using subdirectories named for the common first
letters of the terminal types named therein. System V used
this scheme.
• If ncurses is configured to use hashed databases, then TERM‐
INFO may name its location, such as /usr/share/terminfo.db,
rather than /usr/share/terminfo/.
The hashed database uses less disk space and is a little faster
than the directory tree. However, some applications assume the
existence of the directory tree and read it directly, ignoring the
terminfo API.
• If ncurses is configured with termcap support, this variable
may contain the location of a termcap file.
• If the value of TERMINFO begins with “hex:” or “b64:”, ncurses
uses the remainder of the value as a compiled terminfo
description. You might produce the base64 format using
infocmp(1M).
TERMINFO=$(infocmp -0 -Q2 -q)
export TERMINFO
ncurses uses the compiled description only if it corresponds
to the terminal type identified by TERM.
Setting TERMINFO is the simplest, but not the only, way to direct
ncurses to a terminal database. The search path is as follows.
• the last terminal database to which the running ncurses
application wrote, if any
• the location specified by the TERMINFO environment variable
• $HOME/.terminfo
• locations listed in the TERMINFO_DIRS environment variable
• location(s) configured and compiled into ncurses
• @TERMINFO_DIRS@
• terminfo
TERMINFO_DIRS
This variable specifies a list of locations, akin to PATH, in
which ncurses searches for the terminal type descriptions
described by TERMINFO above. The list items are separated by
colons on Unix and semicolons on OS/2 EMX. System V terminfo
lacks a corresponding feature; TERMINFO_DIRS is an ncurses
extension.
TERMPATH
If TERMCAP does not hold a terminal type description or file name,
then ncurses checks the contents of TERMPATH, a list of locations,
akin to PATH, in which it searches for termcap terminal type
descriptions. The list items are separated by colons on Unix and
semicolons on OS/2 EMX.
If both TERMCAP and TERMPATH are unset or invalid, ncurses
searches for the files /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.
--disable-overwrite
Avoid file name conflicts between ncurses and an existing
curses installation on the system. The standard C
preprocessor inclusion for the curses library is as follows.
#include <curses.h>
If ncurses is installed disabling overwrite, it puts its
header files in a subdirectory. Here is an example.
#include <ncurses/curses.h>
With --disable-overwrite, installation also omits a symbolic
link that would cause the compiler's -lcurses option to link
object files with ncurses instead of the system curses
library.
The directory used by this configuration of ncurses is shown
in section “SYNOPSIS” above.
--enable-widec
(default for ABI 6+ since 2023-10-21) Enable support for wide
characters. The configure script renames the ncurses library
(and the tinfo library, if --with-termlib is also specified),
appending “w”. An application desirous of wide-character
support then uses -lncursesw (or -ltinfow) instead of
-lncurses (or -ltinfo) as its linker option. The ncurses++,
panel, form, and menu libraries are renamed similarly.
An application must also define certain C preprocessor
symbols to enable wide-character features in curses header
files to use the extended (wide-character) functions. The
symbol that enables these features has changed since X/Open
Curses Issue 4.
• Originally, the wide-character feature required the
symbol _XOPEN_SOURCE_EXTENDED, but that was valid only
for XPG4 (1996).
• Later, that was deemed conflicting with an _XOPEN_SOURCE
value of 500.
• As of mid-2018, no ncurses feature requires a
_XOPEN_SOURCE value greater than 600. However, X/Open
Curses Issue 7 (2009) recommends defining it to 700.
• Alternatively, you can enable the feature by defining
NCURSES_WIDECHAR with the caveat that some header file
other 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
WINDOW.
If ncurses's header files are installed allowing overwrite
(the default, but see --disable-overwrite above), the wide-
character library's headers should be installed last by
packaging systems and similar, to allow applications to be
built using either library from the same set of headers.
--with-pthread
Enable support for multi-threaded applications. The
configure script renames the ncurses library (and the tinfo
library, if --with-termlib is also specified), appending “t”
(before any “w” added by --enable-widec). An application
desirous of support for multiple threads of execution then
uses, for example, -lncursest (or -ltinfot) instead of
-lncurses (or -ltinfo) as its linker option. The ncurses++,
panel, form, and menu libraries are renamed similarly.
ncursest and ncursestw replace global variables such as LINES
with macros allowing read-only access. At the same time,
they provide functions to set these values. Very few
applications require changes to work with this convention.
--with-shared
--with-normal
--with-debug
--with-profile
Mandate compilation of the ncurses library (and the tinfo
library, if --with-termlib is also specified) in the
specified forms. The shared and normal (static) library
names differ by their suffixes, as with libncurses.so and
libncurses.a. The debugging and profiling libraries add a
“_g” and a “_p” to the roots of these respective names,
forming libncurses_g.so and libncurses_p.a, for example. The
ncurses++, panel, form, and menu libraries are made available
similarly.
--with-termlib
Provide ncurses's lower-level terminal interface functions
(those that do not depend on the SCREEN and WINDOW
abstractions) in a library named tinfo. This arrangement
reduces an application's linking and/or loading times when it
does not require curses's higher-level features.
The following pages document curses functions provided by
tinfo.
• curs_extend(3X) - miscellaneous ncurses extensions
• curs_inopts(3X) - curses input options
• curs_kernel(3X) - low-level curses routines
• curs_termattrs(3X) - curses environment query routines
• curs_termcap(3X) - curses emulation of termcap
• curs_terminfo(3X) - curses interface to terminfo database
• curs_util(3X) - miscellaneous curses utility routines
--with-trace
Expose the curses_trace(3X) function in the ncurses(w) shared
and static libraries. Normally, it is available only in the
debugging library. (If --with-termlib is also specified,
tinfo(w) rather than ncurses(w) supplies the deprecated
trace(3X) function.) An application's configuration script
should check for the function's existence rather than
assuming its confinement to the debugging library.
datadir/tabset
tab stop initialization database
terminfo
compiled terminal capability database
X/Open Curses permits most functions it specifies to be made
available as macros as well. ncurses does so
• for functions that return values via their parameters,
• to support obsolete features,
• to reuse functions (for example, those that move the cursor
before another operation), and
• in 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 curses.
See subsection “Header Files” below regarding symbols exposed by
inclusion of curses.h.
ncurses enables an application to capture mouse events from
certain terminals, including xterm(1); 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 events at runtime; see define_key(3X),
key_defined(3X), keybound(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 eschew knowledge of SCREEN and WINDOW
structure internals, instead using accessor functions such as
is_cbreak(3X) and is_scrollok(3X).
ncurses enables an application to direct its 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 supported.
ncurses permits modification of unctrl(3X)'s behavior; see
use_legacy_coding(3X).
Rudimentary support for multi-threaded applications may be
available; see curs_threads(3X).
Functions that ease the management of multiple screens can be
exposed; see curs_sp_funcs(3X).
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).
The library facilitates auditing and troubleshooting of its
behavior; see curs_trace(3X).
Compiling ncurses with the option -DUSE_GETCAP causes it to fall
back to reading /etc/termcap if the terminal setup code cannot
find a terminfo entry corresponding to TERM. Use of this feature
is not recommended, as it essentially includes an entire termcap
compiler in the ncurses startup code, at 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 all features of its
enhanced level except the untic utility.
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, ncurses checks pointer parameters,
such as those to WINDOW structures, to ensure that they are not
null. This is done primarily 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 occurred. An
application that relies on ncurses to check its function
parameters for validity limits its portability and robustness.
Padding Differences
In historical curses implementations, delays embedded in the term‐
info capabilities carriage_return (cr), scroll_forward (ind),
cursor_left (cub1), form_feed (ff), and tab (ht) activated
corresponding delay bits in the Unix terminal driver. ncurses
performs all padding by sending NUL bytes to the device. This
method is slightly more expensive, but narrows the interface to
the Unix kernel significantly and correspondingly increases the
package's portability.
Header Files
The header file curses.h itself includes the header files stdio.h
and unctrl.h.
X/Open Curses has more to say,
The inclusion of curses.h may make visible all symbols from
the headers stdio.h, term.h, termios.h, and wchar.h.
but does not finish the story. A more complete account follows.
• The first curses, in 4BSD, provided a curses.h file.
BSD curses code included curses.h and unctrl.h from an
internal header file curses.ext, where “ext” abbreviated
“externs”.
The implementations of printw and scanw used undocumented
internal functions of the standard I/O library (_doprnt and
_doscan), but nothing in curses.h itself relied upon stdio.h.
• SVr2 curses added newterm, which relies upon stdio.h because
its function prototype employs the FILE type.
SVr4 curses added putwin and getwin, which also use stdio.h.
X/Open Curses specifies all three of these functions.
SVr4 curses and X/Open Curses do not require the developer to
include stdio.h before curses.h. Both document use of curses
as requiring only curses.h.
As a result, standard curses.h always includes stdio.h.
• X/Open Curses and SVr4 curses are inconsistent with respect to
unctrl.h.
As noted in curs_util(3X), ncurses includes unctrl.h from
curses.h (as SVr4 does).
• X/Open Curses'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.
• X/Open Curses says that curses.h may include term.h, but does
not require it to do so.
Some programs use functions declared in both curses.h and
term.h, and must include both header files in the same
translation unit.
The header files supplied by ncurses include the standard
library headers required for its declarations, so ncurses's
own header files can be included in any order. For
portability even to old AIX systems, include curses.h before
term.h.
• X/Open Curses says “may make visible” because including a
header file does not necessarily make visible all of the
symbols in it (consider #ifdef and similar).
For instance, ncurses's curses.h may include wchar.h if the
proper symbol is defined, and if ncurses is configured for
wide-character support. If wchar.h is included, its symbols
may be made visible depending on the value of the
_XOPEN_SOURCE feature test macro.
• X/Open Curses mandates an application's inclusion of one
standard C library header in a special case: stdarg.h before
curses.h to prototype the functions vw_printw and vw_scanw (as
well as the obsolete vwprintw and vwscanw). Each of these
takes a variadic argument list, a va_list parameter, like that
of printf(3).
SVr3 curses introduced the two obsolete functions, and X/Open
Curses the others. In between, SVr4 curses provided for the
possibility that an application might include either varargs.h
or stdarg.h. These represented contrasting approaches to
handling variadic argument lists. The older interface,
varargs.h, used a pointer to char for variadic functions'
va_list parameter. Later, the list acquired its own standard
data type, va_list, defined in stdarg.h, empowering the
compiler to check the types of a function call's actual
parameters against the formal ones declared in its prototype.
No conforming implementations of X/Open Curses require an
application to include stdarg.h before curses.h because they
either have allowed for a special type, or, like ncurses, they
include stdarg.h themselves 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)
This page is part of the ncurses (new curses) project.
Information about the project can be found at
⟨https://invisible-island.net/ncurses/ncurses.html⟩. If you have a
bug report for this manual page, send it to bug-ncurses@gnu.org.
This page was obtained from the tarball ncurses-6.6.tar.gz fetched
from ⟨https://ftp.gnu.org/gnu/ncurses/⟩ on 2026-01-16. If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for the
page, or you have corrections or improvements to the information
in this COLOPHON (which is not part of the original manual page),
send a mail to man-pages@man7.org
ncurses @NCURSES_MAJOR@.@NCU... 2025-11-11 ncurses(3X)
|
HTML rendering created 2026-01-16 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|