ncurses 6.4 - patch 20231202

[ncurses.git] / man / ncurses.3x

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.\" Copyright 2018-2021,2023 Thomas E. Dickey                                *
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.\" $Id: ncurses.3x,v 1.185 2023/12/03 00:14:35 tom Exp $
.TH ncurses 3X 2023-12-02 "ncurses 6.4" "Library calls"
.ie \n(.g \{\
.ds `` \(lq
.ds '' \(rq
.\}
.el \{\
.ie t .ds `` ``
.el   .ds `` ""
.ie t .ds '' ''
.el   .ds '' ""
.\}
.de bP
.ie n  .IP \(bu 4
.el    .IP \(bu 2
..
.
.ds d @TERMINFO@
.SH NAME
\fB\%ncurses\fP \-
character-cell terminal interface with optimized output
.SH SYNOPSIS
.nf
\fB#include <curses.h>
.fi
.SH DESCRIPTION
The \fBncurses\fP library routines give the user a terminal-independent method
of updating character screens with reasonable optimization.
This implementation is \*(``new curses\*('' (ncurses) and
is the approved replacement for
4.4BSD classic curses, which has been discontinued.
This describes \fBncurses\fP
version @NCURSES_MAJOR@.@NCURSES_MINOR@ (patch @NCURSES_PATCH@).
.PP
The \fBncurses\fP library emulates the curses library of
System V Release 4 Unix (\*(``SVr4\*(''),
and XPG4 (X/Open Portability Guide) curses (also known as XSI curses).
XSI stands for X/Open System Interfaces Extension.
The \fBncurses\fP library is freely redistributable in source form.
.PP
\fI\%ncurses\fP man pages employ several sections to clarify matters of
usage and interoperability with other \fIcurses\fP implementations.
.bP
\*(``NOTES\*('' describes matters and caveats of which any user of the
\fI\%ncurses\fP API should be aware,
such as limitations on the size of an underlying integral type or the
availability of a preprocessor macro for a function
(which prevents its address from being taken).
This section also describes implementation details that will be
significant to the programmer but which are not standardized.
.bP
\*(``EXTENSIONS\*('' presents \fI\%ncurses\fP innovations beyond the
X/Open Curses standard and/or the SVr4 \fIcurses\fP implementation.
They are termed \fIextensions\fP to indicate that they cannot be
implemented solely by using the library API, but require access to the
library's internal state.
.bP
\*(``PORTABILITY\*('' discusses matters
(beyond the exercise of extensions)
that should be considered when writing to a \fIcurses\fP standard,
or to multiple implementations.
.bP
\*(``HISTORY\*('' examines points of detail in \fI\%ncurses\fP and other
\fIcurses\fP 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).
.PP
A program using these routines must be linked with the \fB\-lncurses\fP option,
or (if it has been generated) with the debugging library \fB\-lncurses_g\fP.
(Your system integrator may also have installed these libraries under
the names \fB\-lcurses\fP and \fB\-lcurses_g\fP.)
The ncurses_g library generates trace logs
(in a file called \*(``trace\*('' in the current directory)
that describe curses actions.
See also the section on \fBALTERNATE CONFIGURATIONS\fP.
.PP
The \fBncurses\fP package supports: overall screen, window and pad
manipulation; output to windows and pads; reading terminal input; control over
terminal and \fBcurses\fP input and output options; environment query
routines; color manipulation; use of soft label keys; terminfo capabilities;
and access to low-level terminal-manipulation routines.
.SS Initialization
The library uses the locale which the calling program has initialized.
That is normally done with \fBsetlocale\fP(3):
.PP
.RS 4
.EX
\fBsetlocale(LC_ALL, "");\fP
.EE
.RE
.PP
If the locale is not initialized,
the library assumes that characters are printable as in ISO\-8859\-1,
to work with certain legacy programs.
You should initialize the locale and not rely on specific details of
the library when the locale has not been setup.
.PP
The function \fBinitscr\fP or \fBnewterm\fP
must be called to initialize the library
before any of the other routines that deal with windows
and screens are used.
The routine \fBendwin\fP(3X) must be called before exiting.
.PP
To get character-at-a-time input without echoing (most
interactive, screen oriented programs want this), the following
sequence should be used:
.PP
.RS 4
.EX
\fBinitscr(); cbreak(); noecho();\fP
.EE
.RE
.PP
Most programs would additionally use the sequence:
.PP
.RS 4
.EX
\fBintrflush(stdscr, FALSE);\fP
\fBkeypad(stdscr, TRUE);\fP
.EE
.RE
.PP
Before a \fBcurses\fP 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 \fB@TPUT@ init\fP command
after the shell environment variable \fITERM\fP has been exported.
(The BSD-style \fB\%@TSET@\fP(1) utility also performs this function.)
See subsection \*(``Tabs and Initialization\*('' of \fBterminfo\fP(5).
.SS Datatypes
The \fBncurses\fP library permits manipulation of data structures,
called \fIwindows\fP, which can be thought of as two-dimensional
arrays of characters representing all or part of a CRT screen.
A default window called \fBstdscr\fP, which is the size of the terminal
screen, is supplied.
Others may be created with \fBnewwin\fP.
.PP
Note that \fBcurses\fP does not handle overlapping windows, that's done by
the \fBpanel\fP(3X) library.
This means that you can either use
\fBstdscr\fP or divide the screen into tiled windows and not using
\fBstdscr\fP at all.
Mixing the two will result in unpredictable, and undesired, effects.
.PP
Windows are referred to by variables declared as \fBWINDOW *\fP.
These data structures are manipulated with routines described here and
elsewhere in the \fBncurses\fP manual pages.
Among those, the most basic
routines are \fBmove\fP and \fBaddch\fP.
More general versions of
these routines are included with names beginning with \fBw\fP,
allowing the user to specify a window.
The routines not beginning
with \fBw\fP affect \fBstdscr\fP.
.PP
After using routines to manipulate a window, \fBrefresh\fP(3X) is called,
telling \fBcurses\fP to make the user's CRT screen look like
\fBstdscr\fP.
The characters in a window are actually of type
\fBchtype\fP, (character and attribute data) so that other information
about the character may also be stored with each character.
.PP
Special windows called \fIpads\fP may also be manipulated.
These are windows
which are not constrained to the size of the screen and whose contents need not
be completely displayed.
See \fBcurs_pad\fP(3X) for more information.
.PP
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, \fBcurses\fP 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 \fB<curses.h>\fP,
such as \fBA_REVERSE\fP, \fBACS_HLINE\fP, and \fBKEY_LEFT\fP.
.SS Environment variables
If the environment variables \fILINES\fP and \fI\%COLUMNS\fP are set,
or if the
program is executing in a window environment, line and column information in
the environment will override information read by \fIterminfo\fP.
This would affect a program running in an AT&T 630 layer,
for example, where the size of a
screen is changeable (see \fBENVIRONMENT\fP).
.PP
If the environment variable \fI\%TERMINFO\fP is defined,
any program using
\fBcurses\fP checks for a local terminal definition before checking in the
standard place.
For example, if \fITERM\fP is set to \fBatt4424\fP, then the
compiled terminal definition is found in
.PP
.RS 4
.EX
\fB\*d/a/att4424\fP.
.EE
.RE
.PP
(The \fBa\fP is copied from the first letter of \fBatt4424\fP to avoid
creation of huge directories.)
However,
if \fI\%TERMINFO\fP is set to
\fB$HOME/myterms\fP, \fBcurses\fP first checks
.PP
.RS 4
.EX
\fB$HOME/myterms/a/att4424\fP,
.EE
.RE
.PP
and if that fails, it then checks
.PP
.RS 4
.EX
\fB\*d/a/att4424\fP.
.EE
.RE
.PP
This is useful for developing experimental definitions or when write
permission in \fB\*d\fP is not available.
.PP
The integer variables \fBLINES\fP and \fBCOLS\fP are defined in
\fB<curses.h>\fP and will be filled in by \fBinitscr\fP with the size of the
screen.
The constants \fBTRUE\fP and \fBFALSE\fP have the values \fB1\fP and
\fB0\fP, respectively.
.PP
The \fBcurses\fP routines also define the \fBWINDOW *\fP variable \fBcurscr\fP
which is used for certain low-level operations like clearing and redrawing a
screen containing garbage.
The \fBcurscr\fP can be used in only a few routines.
.\"
.SS Routine and Argument Names
Many \fBcurses\fP routines have two or more versions.
The routines prefixed with \fIw\fP require a window argument.
The routines prefixed with \fIp\fP require a pad argument.
Those without a prefix generally use \fBstdscr\fP.
.PP
The routines prefixed with \fBmv\fP require a \fIy\fP and \fIx\fP
coordinate to move to before performing the appropriate action.
The \fBmv\fP routines imply a call to \fBmove\fP before the call to the
other routine.
The coordinate \fIy\fP always refers to the row (of
the window), and \fIx\fP always refers to the column.
The upper left-hand corner is always (0,0), not (1,1).
.PP
The routines prefixed with \fBmvw\fP take both a window argument and
\fIx\fP and \fIy\fP coordinates.
The window argument is always specified before the coordinates.
.PP
In each case, \fIwin\fP is the window affected, and \fIpad\fP is the
pad affected; \fIwin\fP and \fIpad\fP are always pointers to type
\fBWINDOW\fP.
.PP
Option setting routines require a Boolean flag \fIbf\fP with the value
\fBTRUE\fP or \fBFALSE\fP; \fIbf\fP is always of type \fBbool\fP.
Most of the data types used in the library routines,
such as \fBWINDOW\fP, \fBSCREEN\fP, \fBbool\fP, and \fBchtype\fP
are defined in \fB<curses.h>\fP.
Types used for the terminfo routines such as
\fBTERMINAL\fP are defined in \fB<term.h>\fP.
.PP
This manual page describes functions which may appear in any configuration
of the library.
There are two common configurations of the library:
.RS 3
.TP 5
.I ncurses
the \*(``normal\*('' library, which handles 8-bit characters.
The normal (8-bit) library stores characters combined with attributes
in \fBchtype\fP data.
.IP
Attributes alone (no corresponding character) may be stored in \fBchtype\fP
or the equivalent \fBattr_t\fP data.
In either case, the data is stored in something like an integer.
.IP
Each cell (row and column) in a \fBWINDOW\fP is stored as a \fBchtype\fP.
.TP 5
.I ncursesw
the so-called \*(``wide\*('' library, which handles multibyte characters
(see the section on \fBALTERNATE CONFIGURATIONS\fP).
The \*(``wide\*('' library includes all of the calls
from the \*(``normal\*('' library.
It adds about one third more calls using data types which store
multibyte characters:
.RS 5
.TP 5
.B cchar_t
corresponds to \fBchtype\fP.
However it is a structure, because more data is stored than can fit into
an integer.
The characters are large enough to require a full integer value \- and there
may be more than one character per cell.
The video attributes and color are stored in separate fields of the structure.
.IP
Each cell (row and column) in a \fBWINDOW\fP is stored as a \fBcchar_t\fP.
.IP
The \fBsetcchar\fP(3X) and \fBgetcchar\fP(3X)
functions store and retrieve the data from
a \fBcchar_t\fP structure.
.TP 5
.B wchar_t
stores a \*(``wide\*('' character.
Like \fBchtype\fP, this may be an integer.
.TP 5
.B wint_t
stores a \fBwchar_t\fP or \fBWEOF\fP \- not the same, though both may have
the same size.
.RE
.IP
The \*(``wide\*('' library provides new functions which are analogous to
functions in the \*(``normal\*('' library.
There is a naming convention which relates many of the normal/wide variants:
a \*(``_w\*('' is inserted into the name.
For example, \fBwaddch\fP becomes \fBwadd_wch\fP.
.RE
.\"
.SS Routine Name Index
The following table lists the \fBcurses\fP routines provided in
the \*(``normal\*('' and \*(``wide\*('' libraries and the names of
the manual pages on which they are described.
Routines flagged with \*(``*\*(''
are ncurses-specific, not described by XPG4 or present in SVr4.
.PP
.TS
center tab(/);
l l
l l .
\fBcurses\fP Routine Name/Manual Page Name
=
COLOR_PAIR/\fBcurs_color\fP(3X)
PAIR_NUMBER/\fBcurs_attr\fP(3X)
add_wch/\fBcurs_add_wch\fP(3X)
add_wchnstr/\fBcurs_add_wchstr\fP(3X)
add_wchstr/\fBcurs_add_wchstr\fP(3X)
addch/\fBcurs_addch\fP(3X)
addchnstr/\fBcurs_addchstr\fP(3X)
addchstr/\fBcurs_addchstr\fP(3X)
addnstr/\fBcurs_addstr\fP(3X)
addnwstr/\fBcurs_addwstr\fP(3X)
addstr/\fBcurs_addstr\fP(3X)
addwstr/\fBcurs_addwstr\fP(3X)
alloc_pair/\fBnew_pair\fP(3X)*
assume_default_colors/\fBdefault_colors\fP(3X)*
attr_get/\fBcurs_attr\fP(3X)
attr_off/\fBcurs_attr\fP(3X)
attr_on/\fBcurs_attr\fP(3X)
attr_set/\fBcurs_attr\fP(3X)
attroff/\fBcurs_attr\fP(3X)
attron/\fBcurs_attr\fP(3X)
attrset/\fBcurs_attr\fP(3X)
baudrate/\fBcurs_termattrs\fP(3X)
beep/\fBcurs_beep\fP(3X)
bkgd/\fBcurs_bkgd\fP(3X)
bkgdset/\fBcurs_bkgd\fP(3X)
bkgrnd/\fBcurs_bkgrnd\fP(3X)
bkgrndset/\fBcurs_bkgrnd\fP(3X)
border/\fBcurs_border\fP(3X)
border_set/\fBcurs_border_set\fP(3X)
box/\fBcurs_border\fP(3X)
box_set/\fBcurs_border_set\fP(3X)
can_change_color/\fBcurs_color\fP(3X)
cbreak/\fBcurs_inopts\fP(3X)
chgat/\fBcurs_attr\fP(3X)
clear/\fBcurs_clear\fP(3X)
clearok/\fBcurs_outopts\fP(3X)
clrtobot/\fBcurs_clear\fP(3X)
clrtoeol/\fBcurs_clear\fP(3X)
color_content/\fBcurs_color\fP(3X)
color_set/\fBcurs_attr\fP(3X)
copywin/\fBcurs_overlay\fP(3X)
curs_set/\fBcurs_kernel\fP(3X)
curses_trace/\fBcurs_trace\fP(3X)*
curses_version/\fBcurs_extend\fP(3X)*
def_prog_mode/\fBcurs_kernel\fP(3X)
def_shell_mode/\fBcurs_kernel\fP(3X)
define_key/\fBdefine_key\fP(3X)*
del_curterm/\fBcurs_terminfo\fP(3X)
delay_output/\fBcurs_util\fP(3X)
delch/\fBcurs_delch\fP(3X)
deleteln/\fBcurs_deleteln\fP(3X)
delscreen/\fBcurs_initscr\fP(3X)
delwin/\fBcurs_window\fP(3X)
derwin/\fBcurs_window\fP(3X)
doupdate/\fBcurs_refresh\fP(3X)
dupwin/\fBcurs_window\fP(3X)
echo/\fBcurs_inopts\fP(3X)
echo_wchar/\fBcurs_add_wch\fP(3X)
echochar/\fBcurs_addch\fP(3X)
endwin/\fBcurs_initscr\fP(3X)
erase/\fBcurs_clear\fP(3X)
erasechar/\fBcurs_termattrs\fP(3X)
erasewchar/\fBcurs_termattrs\fP(3X)
exit_curses/\fBcurs_memleaks\fP(3X)*
exit_terminfo/\fBcurs_memleaks\fP(3X)*
extended_color_content/\fBcurs_color\fP(3X)*
extended_pair_content/\fBcurs_color\fP(3X)*
extended_slk_color/\fBcurs_slk\fP(3X)*
filter/\fBcurs_util\fP(3X)
find_pair/\fBnew_pair\fP(3X)*
flash/\fBcurs_beep\fP(3X)
flushinp/\fBcurs_util\fP(3X)
free_pair/\fBnew_pair\fP(3X)*
get_wch/\fBcurs_get_wch\fP(3X)
get_wstr/\fBcurs_get_wstr\fP(3X)
getattrs/\fBcurs_attr\fP(3X)
getbegx/\fBcurs_legacy\fP(3X)*
getbegy/\fBcurs_legacy\fP(3X)*
getbegyx/\fBcurs_getyx\fP(3X)
getbkgd/\fBcurs_bkgd\fP(3X)
getbkgrnd/\fBcurs_bkgrnd\fP(3X)
getcchar/\fBcurs_getcchar\fP(3X)
getch/\fBcurs_getch\fP(3X)
getcurx/\fBcurs_legacy\fP(3X)*
getcury/\fBcurs_legacy\fP(3X)*
getmaxx/\fBcurs_legacy\fP(3X)*
getmaxy/\fBcurs_legacy\fP(3X)*
getmaxyx/\fBcurs_getyx\fP(3X)
getmouse/\fBcurs_mouse\fP(3X)*
getn_wstr/\fBcurs_get_wstr\fP(3X)
getnstr/\fBcurs_getstr\fP(3X)
getparx/\fBcurs_legacy\fP(3X)*
getpary/\fBcurs_legacy\fP(3X)*
getparyx/\fBcurs_getyx\fP(3X)
getstr/\fBcurs_getstr\fP(3X)
getsyx/\fBcurs_kernel\fP(3X)
getwin/\fBcurs_util\fP(3X)
getyx/\fBcurs_getyx\fP(3X)
halfdelay/\fBcurs_inopts\fP(3X)
has_colors/\fBcurs_color\fP(3X)
has_ic/\fBcurs_termattrs\fP(3X)
has_il/\fBcurs_termattrs\fP(3X)
has_key/\fBcurs_getch\fP(3X)*
has_mouse/\fBcurs_mouse\fP(3X)*
hline/\fBcurs_border\fP(3X)
hline_set/\fBcurs_border_set\fP(3X)
idcok/\fBcurs_outopts\fP(3X)
idlok/\fBcurs_outopts\fP(3X)
immedok/\fBcurs_outopts\fP(3X)
in_wch/\fBcurs_in_wch\fP(3X)
in_wchnstr/\fBcurs_in_wchstr\fP(3X)
in_wchstr/\fBcurs_in_wchstr\fP(3X)
inch/\fBcurs_inch\fP(3X)
inchnstr/\fBcurs_inchstr\fP(3X)
inchstr/\fBcurs_inchstr\fP(3X)
init_color/\fBcurs_color\fP(3X)
init_extended_color/\fBcurs_color\fP(3X)*
init_extended_pair/\fBcurs_color\fP(3X)*
init_pair/\fBcurs_color\fP(3X)
initscr/\fBcurs_initscr\fP(3X)
innstr/\fBcurs_instr\fP(3X)
innwstr/\fBcurs_inwstr\fP(3X)
ins_nwstr/\fBcurs_ins_wstr\fP(3X)
ins_wch/\fBcurs_ins_wch\fP(3X)
ins_wstr/\fBcurs_ins_wstr\fP(3X)
insch/\fBcurs_insch\fP(3X)
insdelln/\fBcurs_deleteln\fP(3X)
insertln/\fBcurs_deleteln\fP(3X)
insnstr/\fBcurs_insstr\fP(3X)
insstr/\fBcurs_insstr\fP(3X)
instr/\fBcurs_instr\fP(3X)
intrflush/\fBcurs_inopts\fP(3X)
inwstr/\fBcurs_inwstr\fP(3X)
is_cbreak/\fBcurs_inopts\fP(3X)*
is_cleared/\fBcurs_opaque\fP(3X)*
is_echo/\fBcurs_inopts\fP(3X)*
is_idcok/\fBcurs_opaque\fP(3X)*
is_idlok/\fBcurs_opaque\fP(3X)*
is_immedok/\fBcurs_opaque\fP(3X)*
is_keypad/\fBcurs_opaque\fP(3X)*
is_leaveok/\fBcurs_opaque\fP(3X)*
is_linetouched/\fBcurs_touch\fP(3X)
is_nl/\fBcurs_inopts\fP(3X)*
is_nodelay/\fBcurs_opaque\fP(3X)*
is_notimeout/\fBcurs_opaque\fP(3X)*
is_pad/\fBcurs_opaque\fP(3X)*
is_raw/\fBcurs_inopts\fP(3X)*
is_scrollok/\fBcurs_opaque\fP(3X)*
is_subwin/\fBcurs_opaque\fP(3X)*
is_syncok/\fBcurs_opaque\fP(3X)*
is_term_resized/\fBresizeterm\fP(3X)*
is_wintouched/\fBcurs_touch\fP(3X)
isendwin/\fBcurs_initscr\fP(3X)
key_defined/\fBkey_defined\fP(3X)*
key_name/\fBcurs_util\fP(3X)
keybound/\fBkeybound\fP(3X)*
keyname/\fBcurs_util\fP(3X)
keyok/\fBkeyok\fP(3X)*
keypad/\fBcurs_inopts\fP(3X)
killchar/\fBcurs_termattrs\fP(3X)
killwchar/\fBcurs_termattrs\fP(3X)
leaveok/\fBcurs_outopts\fP(3X)
longname/\fBcurs_termattrs\fP(3X)
mcprint/\fBcurs_print\fP(3X)*
meta/\fBcurs_inopts\fP(3X)
mouse_trafo/\fBcurs_mouse\fP(3X)*
mouseinterval/\fBcurs_mouse\fP(3X)*
mousemask/\fBcurs_mouse\fP(3X)*
move/\fBcurs_move\fP(3X)
mvadd_wch/\fBcurs_add_wch\fP(3X)
mvadd_wchnstr/\fBcurs_add_wchstr\fP(3X)
mvadd_wchstr/\fBcurs_add_wchstr\fP(3X)
mvaddch/\fBcurs_addch\fP(3X)
mvaddchnstr/\fBcurs_addchstr\fP(3X)
mvaddchstr/\fBcurs_addchstr\fP(3X)
mvaddnstr/\fBcurs_addstr\fP(3X)
mvaddnwstr/\fBcurs_addwstr\fP(3X)
mvaddstr/\fBcurs_addstr\fP(3X)
mvaddwstr/\fBcurs_addwstr\fP(3X)
mvchgat/\fBcurs_attr\fP(3X)
mvcur/\fBcurs_terminfo\fP(3X)
mvdelch/\fBcurs_delch\fP(3X)
mvderwin/\fBcurs_window\fP(3X)
mvget_wch/\fBcurs_get_wch\fP(3X)
mvget_wstr/\fBcurs_get_wstr\fP(3X)
mvgetch/\fBcurs_getch\fP(3X)
mvgetn_wstr/\fBcurs_get_wstr\fP(3X)
mvgetnstr/\fBcurs_getstr\fP(3X)
mvgetstr/\fBcurs_getstr\fP(3X)
mvhline/\fBcurs_border\fP(3X)
mvhline_set/\fBcurs_border_set\fP(3X)
mvin_wch/\fBcurs_in_wch\fP(3X)
mvin_wchnstr/\fBcurs_in_wchstr\fP(3X)
mvin_wchstr/\fBcurs_in_wchstr\fP(3X)
mvinch/\fBcurs_inch\fP(3X)
mvinchnstr/\fBcurs_inchstr\fP(3X)
mvinchstr/\fBcurs_inchstr\fP(3X)
mvinnstr/\fBcurs_instr\fP(3X)
mvinnwstr/\fBcurs_inwstr\fP(3X)
mvins_nwstr/\fBcurs_ins_wstr\fP(3X)
mvins_wch/\fBcurs_ins_wch\fP(3X)
mvins_wstr/\fBcurs_ins_wstr\fP(3X)
mvinsch/\fBcurs_insch\fP(3X)
mvinsnstr/\fBcurs_insstr\fP(3X)
mvinsstr/\fBcurs_insstr\fP(3X)
mvinstr/\fBcurs_instr\fP(3X)
mvinwstr/\fBcurs_inwstr\fP(3X)
mvprintw/\fBcurs_printw\fP(3X)
mvscanw/\fBcurs_scanw\fP(3X)
mvvline/\fBcurs_border\fP(3X)
mvvline_set/\fBcurs_border_set\fP(3X)
mvwadd_wch/\fBcurs_add_wch\fP(3X)
mvwadd_wchnstr/\fBcurs_add_wchstr\fP(3X)
mvwadd_wchstr/\fBcurs_add_wchstr\fP(3X)
mvwaddch/\fBcurs_addch\fP(3X)
mvwaddchnstr/\fBcurs_addchstr\fP(3X)
mvwaddchstr/\fBcurs_addchstr\fP(3X)
mvwaddnstr/\fBcurs_addstr\fP(3X)
mvwaddnwstr/\fBcurs_addwstr\fP(3X)
mvwaddstr/\fBcurs_addstr\fP(3X)
mvwaddwstr/\fBcurs_addwstr\fP(3X)
mvwchgat/\fBcurs_attr\fP(3X)
mvwdelch/\fBcurs_delch\fP(3X)
mvwget_wch/\fBcurs_get_wch\fP(3X)
mvwget_wstr/\fBcurs_get_wstr\fP(3X)
mvwgetch/\fBcurs_getch\fP(3X)
mvwgetn_wstr/\fBcurs_get_wstr\fP(3X)
mvwgetnstr/\fBcurs_getstr\fP(3X)
mvwgetstr/\fBcurs_getstr\fP(3X)
mvwhline/\fBcurs_border\fP(3X)
mvwhline_set/\fBcurs_border_set\fP(3X)
mvwin/\fBcurs_window\fP(3X)
mvwin_wch/\fBcurs_in_wch\fP(3X)
mvwin_wchnstr/\fBcurs_in_wchstr\fP(3X)
mvwin_wchstr/\fBcurs_in_wchstr\fP(3X)
mvwinch/\fBcurs_inch\fP(3X)
mvwinchnstr/\fBcurs_inchstr\fP(3X)
mvwinchstr/\fBcurs_inchstr\fP(3X)
mvwinnstr/\fBcurs_instr\fP(3X)
mvwinnwstr/\fBcurs_inwstr\fP(3X)
mvwins_nwstr/\fBcurs_ins_wstr\fP(3X)
mvwins_wch/\fBcurs_ins_wch\fP(3X)
mvwins_wstr/\fBcurs_ins_wstr\fP(3X)
mvwinsch/\fBcurs_insch\fP(3X)
mvwinsnstr/\fBcurs_insstr\fP(3X)
mvwinsstr/\fBcurs_insstr\fP(3X)
mvwinstr/\fBcurs_instr\fP(3X)
mvwinwstr/\fBcurs_inwstr\fP(3X)
mvwprintw/\fBcurs_printw\fP(3X)
mvwscanw/\fBcurs_scanw\fP(3X)
mvwvline/\fBcurs_border\fP(3X)
mvwvline_set/\fBcurs_border_set\fP(3X)
napms/\fBcurs_kernel\fP(3X)
newpad/\fBcurs_pad\fP(3X)
newterm/\fBcurs_initscr\fP(3X)
newwin/\fBcurs_window\fP(3X)
nl/\fBcurs_inopts\fP(3X)
nocbreak/\fBcurs_inopts\fP(3X)
nodelay/\fBcurs_inopts\fP(3X)
noecho/\fBcurs_inopts\fP(3X)
nofilter/\fBcurs_util\fP(3X)*
nonl/\fBcurs_inopts\fP(3X)
noqiflush/\fBcurs_inopts\fP(3X)
noraw/\fBcurs_inopts\fP(3X)
notimeout/\fBcurs_inopts\fP(3X)
overlay/\fBcurs_overlay\fP(3X)
overwrite/\fBcurs_overlay\fP(3X)
pair_content/\fBcurs_color\fP(3X)
pecho_wchar/\fBcurs_pad\fP(3X)
pechochar/\fBcurs_pad\fP(3X)
pnoutrefresh/\fBcurs_pad\fP(3X)
prefresh/\fBcurs_pad\fP(3X)
printw/\fBcurs_printw\fP(3X)
putp/\fBcurs_terminfo\fP(3X)
putwin/\fBcurs_util\fP(3X)
qiflush/\fBcurs_inopts\fP(3X)
raw/\fBcurs_inopts\fP(3X)
redrawwin/\fBcurs_refresh\fP(3X)
refresh/\fBcurs_refresh\fP(3X)
reset_color_pairs/\fBcurs_color\fP(3X)*
reset_prog_mode/\fBcurs_kernel\fP(3X)
reset_shell_mode/\fBcurs_kernel\fP(3X)
resetty/\fBcurs_kernel\fP(3X)
resize_term/\fBresizeterm\fP(3X)*
resizeterm/\fBresizeterm\fP(3X)*
restartterm/\fBcurs_terminfo\fP(3X)
ripoffline/\fBcurs_kernel\fP(3X)
savetty/\fBcurs_kernel\fP(3X)
scanw/\fBcurs_scanw\fP(3X)
scr_dump/\fBcurs_scr_dump\fP(3X)
scr_init/\fBcurs_scr_dump\fP(3X)
scr_restore/\fBcurs_scr_dump\fP(3X)
scr_set/\fBcurs_scr_dump\fP(3X)
scrl/\fBcurs_scroll\fP(3X)
scroll/\fBcurs_scroll\fP(3X)
scrollok/\fBcurs_outopts\fP(3X)
set_curterm/\fBcurs_terminfo\fP(3X)
set_term/\fBcurs_initscr\fP(3X)
setcchar/\fBcurs_getcchar\fP(3X)
setscrreg/\fBcurs_outopts\fP(3X)
setsyx/\fBcurs_kernel\fP(3X)
setupterm/\fBcurs_terminfo\fP(3X)
slk_attr/\fBcurs_slk\fP(3X)*
slk_attr_off/\fBcurs_slk\fP(3X)
slk_attr_on/\fBcurs_slk\fP(3X)
slk_attr_set/\fBcurs_slk\fP(3X)
slk_attroff/\fBcurs_slk\fP(3X)
slk_attron/\fBcurs_slk\fP(3X)
slk_attrset/\fBcurs_slk\fP(3X)
slk_clear/\fBcurs_slk\fP(3X)
slk_color/\fBcurs_slk\fP(3X)
slk_init/\fBcurs_slk\fP(3X)
slk_label/\fBcurs_slk\fP(3X)
slk_noutrefresh/\fBcurs_slk\fP(3X)
slk_refresh/\fBcurs_slk\fP(3X)
slk_restore/\fBcurs_slk\fP(3X)
slk_set/\fBcurs_slk\fP(3X)
slk_touch/\fBcurs_slk\fP(3X)
slk_wset/\fBcurs_slk\fP(3X)
standend/\fBcurs_attr\fP(3X)
standout/\fBcurs_attr\fP(3X)
start_color/\fBcurs_color\fP(3X)
subpad/\fBcurs_pad\fP(3X)
subwin/\fBcurs_window\fP(3X)
syncok/\fBcurs_window\fP(3X)
term_attrs/\fBcurs_termattrs\fP(3X)
termattrs/\fBcurs_termattrs\fP(3X)
termname/\fBcurs_termattrs\fP(3X)
tgetent/\fBcurs_termcap\fP(3X)
tgetflag/\fBcurs_termcap\fP(3X)
tgetnum/\fBcurs_termcap\fP(3X)
tgetstr/\fBcurs_termcap\fP(3X)
tgoto/\fBcurs_termcap\fP(3X)
tigetflag/\fBcurs_terminfo\fP(3X)
tigetnum/\fBcurs_terminfo\fP(3X)
tigetstr/\fBcurs_terminfo\fP(3X)
timeout/\fBcurs_inopts\fP(3X)
tiparm/\fBcurs_terminfo\fP(3X)
tiparm_s/\fBcurs_terminfo\fP(3X)*
tiscan_s/\fBcurs_terminfo\fP(3X)*
touchline/\fBcurs_touch\fP(3X)
touchwin/\fBcurs_touch\fP(3X)
tparm/\fBcurs_terminfo\fP(3X)
tputs/\fBcurs_termcap\fP(3X)
tputs/\fBcurs_terminfo\fP(3X)
trace/\fBcurs_trace\fP(3X)*
typeahead/\fBcurs_inopts\fP(3X)
unctrl/\fBcurs_util\fP(3X)
unget_wch/\fBcurs_get_wch\fP(3X)
ungetch/\fBcurs_getch\fP(3X)
ungetmouse/\fBcurs_mouse\fP(3X)*
untouchwin/\fBcurs_touch\fP(3X)
use_default_colors/\fBdefault_colors\fP(3X)*
use_env/\fBcurs_util\fP(3X)
use_extended_names/\fBcurs_extend\fP(3X)*
use_legacy_coding/\fBlegacy_coding\fP(3X)*
use_tioctl/\fBcurs_util\fP(3X)*
vid_attr/\fBcurs_terminfo\fP(3X)
vid_puts/\fBcurs_terminfo\fP(3X)
vidattr/\fBcurs_terminfo\fP(3X)
vidputs/\fBcurs_terminfo\fP(3X)
vline/\fBcurs_border\fP(3X)
vline_set/\fBcurs_border_set\fP(3X)
vw_printw/\fBcurs_printw\fP(3X)
vw_scanw/\fBcurs_scanw\fP(3X)
vwprintw/\fBcurs_printw\fP(3X)
vwscanw/\fBcurs_scanw\fP(3X)
wadd_wch/\fBcurs_add_wch\fP(3X)
wadd_wchnstr/\fBcurs_add_wchstr\fP(3X)
wadd_wchstr/\fBcurs_add_wchstr\fP(3X)
waddch/\fBcurs_addch\fP(3X)
waddchnstr/\fBcurs_addchstr\fP(3X)
waddchstr/\fBcurs_addchstr\fP(3X)
waddnstr/\fBcurs_addstr\fP(3X)
waddnwstr/\fBcurs_addwstr\fP(3X)
waddstr/\fBcurs_addstr\fP(3X)
waddwstr/\fBcurs_addwstr\fP(3X)
wattr_get/\fBcurs_attr\fP(3X)
wattr_off/\fBcurs_attr\fP(3X)
wattr_on/\fBcurs_attr\fP(3X)
wattr_set/\fBcurs_attr\fP(3X)
wattroff/\fBcurs_attr\fP(3X)
wattron/\fBcurs_attr\fP(3X)
wattrset/\fBcurs_attr\fP(3X)
wbkgd/\fBcurs_bkgd\fP(3X)
wbkgdset/\fBcurs_bkgd\fP(3X)
wbkgrnd/\fBcurs_bkgrnd\fP(3X)
wbkgrndset/\fBcurs_bkgrnd\fP(3X)
wborder/\fBcurs_border\fP(3X)
wborder_set/\fBcurs_border_set\fP(3X)
wchgat/\fBcurs_attr\fP(3X)
wclear/\fBcurs_clear\fP(3X)
wclrtobot/\fBcurs_clear\fP(3X)
wclrtoeol/\fBcurs_clear\fP(3X)
wcolor_set/\fBcurs_attr\fP(3X)
wcursyncup/\fBcurs_window\fP(3X)
wdelch/\fBcurs_delch\fP(3X)
wdeleteln/\fBcurs_deleteln\fP(3X)
wecho_wchar/\fBcurs_add_wch\fP(3X)
wechochar/\fBcurs_addch\fP(3X)
wenclose/\fBcurs_mouse\fP(3X)*
werase/\fBcurs_clear\fP(3X)
wget_wch/\fBcurs_get_wch\fP(3X)
wget_wstr/\fBcurs_get_wstr\fP(3X)
wgetbkgrnd/\fBcurs_bkgrnd\fP(3X)
wgetch/\fBcurs_getch\fP(3X)
wgetdelay/\fBcurs_opaque\fP(3X)*
wgetn_wstr/\fBcurs_get_wstr\fP(3X)
wgetnstr/\fBcurs_getstr\fP(3X)
wgetparent/\fBcurs_opaque\fP(3X)*
wgetscrreg/\fBcurs_opaque\fP(3X)*
wgetstr/\fBcurs_getstr\fP(3X)
whline/\fBcurs_border\fP(3X)
whline_set/\fBcurs_border_set\fP(3X)
win_wch/\fBcurs_in_wch\fP(3X)
win_wchnstr/\fBcurs_in_wchstr\fP(3X)
win_wchstr/\fBcurs_in_wchstr\fP(3X)
winch/\fBcurs_inch\fP(3X)
winchnstr/\fBcurs_inchstr\fP(3X)
winchstr/\fBcurs_inchstr\fP(3X)
winnstr/\fBcurs_instr\fP(3X)
winnwstr/\fBcurs_inwstr\fP(3X)
wins_nwstr/\fBcurs_ins_wstr\fP(3X)
wins_wch/\fBcurs_ins_wch\fP(3X)
wins_wstr/\fBcurs_ins_wstr\fP(3X)
winsch/\fBcurs_insch\fP(3X)
winsdelln/\fBcurs_deleteln\fP(3X)
winsertln/\fBcurs_deleteln\fP(3X)
winsnstr/\fBcurs_insstr\fP(3X)
winsstr/\fBcurs_insstr\fP(3X)
winstr/\fBcurs_instr\fP(3X)
winwstr/\fBcurs_inwstr\fP(3X)
wmouse_trafo/\fBcurs_mouse\fP(3X)*
wmove/\fBcurs_move\fP(3X)
wnoutrefresh/\fBcurs_refresh\fP(3X)
wprintw/\fBcurs_printw\fP(3X)
wredrawln/\fBcurs_refresh\fP(3X)
wrefresh/\fBcurs_refresh\fP(3X)
wresize/\fBwresize\fP(3X)*
wscanw/\fBcurs_scanw\fP(3X)
wscrl/\fBcurs_scroll\fP(3X)
wsetscrreg/\fBcurs_outopts\fP(3X)
wstandend/\fBcurs_attr\fP(3X)
wstandout/\fBcurs_attr\fP(3X)
wsyncdown/\fBcurs_window\fP(3X)
wsyncup/\fBcurs_window\fP(3X)
wtimeout/\fBcurs_inopts\fP(3X)
wtouchln/\fBcurs_touch\fP(3X)
wunctrl/\fBcurs_util\fP(3X)
wvline/\fBcurs_border\fP(3X)
wvline_set/\fBcurs_border_set\fP(3X)
.TE
.PP
Depending on the configuration,
additional sets of functions may be available:
.RS 3
.TP 5
\fBcurs_memleaks\fP(3X) - curses memory-leak checking
.TP 5
\fBcurs_sp_funcs\fP(3X) - curses screen-pointer extension
.TP 5
\fBcurs_threads\fP(3X) - curses thread support
.TP 5
\fBcurs_trace\fP(3X) - curses debugging routines
.RE
.SH RETURN VALUE
Routines that return an integer return \fBERR\fP upon failure and an
integer value other than \fBERR\fP upon successful completion, unless
otherwise noted in the routine descriptions.
.PP
As a general rule, routines check for null pointers passed as parameters,
and handle this as an error.
.PP
All macros return the value of the \fBw\fP version, except \fBsetscrreg\fP,
\fBwsetscrreg\fP, \fBgetyx\fP, \fBgetbegyx\fP, and \fBgetmaxyx\fP.
The return values of
\fBsetscrreg\fP,
\fBwsetscrreg\fP,
\fBgetyx\fP,
\fBgetbegyx\fP, and
\fBgetmaxyx\fP are undefined (i.e., these should not be used as the
right-hand side of assignment statements).
.PP
Functions with a \*(``mv\*('' prefix first perform a cursor movement using
\fBwmove\fP, and return an error if the position is outside the window,
or if the window pointer is null.
Most \*(``mv\*(''-prefixed functions
(except variadic functions such as \fBmvprintw\fP)
are provided both as macros and functions.
.PP
Routines that return pointers return \fBNULL\fP on error.
.SH ENVIRONMENT
The following environment symbols are useful for customizing the
runtime behavior of the \fBncurses\fP library.
The most important ones have been already discussed in detail.
.SS \fICC\fP command-character
When set, change occurrences of the command_character
(i.e., the \fBcmdch\fP capability)
of the loaded terminfo entries to the value of this variable.
Very few terminfo entries provide this feature.
.PP
Because this name is also used in development environments to represent
the C compiler's name, \fBncurses\fP ignores it if it does not happen to
be a single character.
.SS \fIBAUDRATE\fP
The debugging library checks this environment variable when the application
has redirected output to a file.
The variable's numeric value is used for the baudrate.
If no value is found, \fBncurses\fP uses 9600.
This allows testers to construct repeatable test-cases
that take into account costs that depend on baudrate.
.SS \fICOLUMNS\fP
Specify the width of the screen in characters.
Applications running in a windowing environment usually are able to
obtain the width of the window in which they are executing.
If neither the \fI\%COLUMNS\fP value nor the terminal's screen size is available,
\fBncurses\fP uses the size which may be specified in the terminfo database
(i.e., the \fBcols\fP capability).
.PP
It is important that your application use a correct size for the screen.
This is not always possible because your application may be
running on a host which does not honor NAWS (Negotiations About Window
Size), or because you are temporarily running as another user.
However,
setting \fI\%COLUMNS\fP and/or \fILINES\fP overrides the library's use
of the screen size obtained from the operating system.
.PP
Either \fI\%COLUMNS\fP or \fILINES\fP symbols may be specified
independently.
This is mainly useful to circumvent legacy misfeatures of terminal descriptions,
e.g., xterm which commonly specifies a 65 line screen.
For best results, \fBlines\fP and \fBcols\fP should not be specified in
a terminal description for terminals which are run as emulations.
.PP
Use the \fBuse_env\fP function to disable all use of external environment
(but not including system calls) to determine the screen size.
Use the \fBuse_tioctl\fP function to update \fI\%COLUMNS\fP or
\fILINES\fP to match the screen size obtained from system calls or the
terminal database.
.SS \fIESCDELAY\fP
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.
.PP
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.
.PP
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.
.PP
In addition to the environment variable,
this implementation provides a global variable with the same name.
Portable applications should not rely upon the presence of \fB\%ESCDELAY\fP
in either form,
but setting the environment variable rather than the global variable
does not create problems when compiling an application.
.SS \fIHOME\fP
Tells \fBncurses\fP where your home directory is.
That is where it may read and write auxiliary terminal descriptions:
.PP
.RS 4
.EX
$HOME/.termcap
$HOME/.terminfo
.EE
.RE
.SS \fILINES\fP
Like \fI\%COLUMNS\fP, specify the height of the screen in characters.
See \fI\%COLUMNS\fP for a detailed description.
.SS \fIMOUSE_BUTTONS_123\fP
This applies only to the OS/2 EMX port.
It specifies the order of buttons on the mouse.
OS/2 numbers a 3-button mouse inconsistently from other
platforms:
.PP
.RS 4
.EX
1 = left
2 = right
3 = middle.
.EE
.RE
.PP
This variable lets you customize the mouse.
The variable must be three numeric digits 1\-3 in any order, e.g., 123 or 321.
If it is not specified, \fBncurses\fP uses 132.
.SS \fINCURSES_ASSUMED_COLORS\fP
Override the compiled-in assumption that the
terminal's default colors are white-on-black
(see \fBdefault_colors\fP(3X)).
You may set the foreground and background color values with this environment
variable by proving a 2-element list: foreground,background.
For example, to tell ncurses to not assume anything
about the colors, set this to "\-1,\-1".
To make it green-on-black, set it to "2,0".
Any positive value from zero to the terminfo \fBmax_colors\fP value is allowed.
.SS \fINCURSES_CONSOLE2\fP
This applies only to the MinGW port of ncurses.
.PP
The \fBConsole2\fP program's handling of the Microsoft Console API call
\fBCreateConsoleScreenBuffer\fP is defective.
Applications which use this will hang.
However, it is possible to simulate the action of this call by
mapping coordinates,
explicitly saving and restoring the original screen contents.
Setting the environment variable \fBNCGDB\fP has the same effect.
.SS \fINCURSES_GPM_TERMS\fP
This applies only to ncurses configured to use the GPM interface.
.PP
If present,
the environment variable is a list of one or more terminal names
against which the \fITERM\fP environment variable is matched.
Setting it to an empty value disables the GPM interface;
using the built-in support for xterm, etc.
.PP
If the environment variable is absent,
ncurses will attempt to open GPM if \fITERM\fP contains \*(``linux\*(''.
.SS \fINCURSES_NO_HARD_TABS\fP
\fBNcurses\fP may use tabs as part of the cursor movement optimization.
In some cases,
your terminal driver may not handle these properly.
Set this environment variable to disable the feature.
You can also adjust your \fBstty\fP(1) settings to avoid the problem.
.SS \fINCURSES_NO_MAGIC_COOKIE\fP
Some terminals use a magic-cookie feature which requires special handling
to make highlighting and other video attributes display properly.
You can suppress the highlighting entirely for these terminals by
setting this environment variable.
.SS \fINCURSES_NO_PADDING\fP
Most of the terminal descriptions in the terminfo database are written
for real \*(``hardware\*('' terminals.
Many people use terminal emulators
which run in a windowing environment and use curses-based applications.
Terminal emulators can duplicate
all of the important aspects of a hardware terminal, but they do not
have the same limitations.
The chief limitation of a hardware terminal from the standpoint
of your application is the management of dataflow, i.e., timing.
Unless a hardware terminal is interfaced into a terminal concentrator
(which does flow control),
it (or your application) must manage dataflow, preventing overruns.
The cheapest solution (no hardware cost)
is for your program to do this by pausing after
operations that the terminal does slowly, such as clearing the display.
.PP
As a result, many terminal descriptions (including the vt100)
have delay times embedded.
You may wish to use these descriptions,
but not want to pay the performance penalty.
.PP
Set the \fI\%NCURSES_NO_PADDING\fP environment variable
to disable all but mandatory padding.
Mandatory padding is used as a part of special control
sequences such as \fBflash\fP.
.SS \fINCURSES_NO_SETBUF\fP
This setting is obsolete.
Before changes
.RS 3
.bP
started with 5.9 patch 20120825
and
.bP
continued
though 5.9 patch 20130126
.RE
.PP
\fBncurses\fP enabled buffered output during terminal initialization.
This was done (as in SVr4 curses) for performance reasons.
For testing purposes, both of \fBncurses\fP and certain applications,
this feature was made optional.
Setting the \fI\%NCURSES_NO_SETBUF\fP variable
disabled output buffering, leaving the output in the original (usually
line buffered) mode.
.PP
In the current implementation,
ncurses performs its own buffering and does not require this workaround.
It does not modify the buffering of the standard output.
.PP
The reason for the change was to make the behavior for interrupts and
other signals more robust.
One drawback is that certain nonconventional programs would mix
ordinary stdio calls with ncurses calls and (usually) work.
This is no longer possible since ncurses is not using
the buffered standard output but its own output (to the same file descriptor).
As a special case, the low-level calls such as \fBputp\fP still use the
standard output.
But high-level curses calls do not.
.SS \fINCURSES_NO_UTF8_ACS\fP
During initialization, the \fBncurses\fP library
checks for special cases where VT100 line-drawing (and the corresponding
alternate character set capabilities) described in the terminfo are known
to be missing.
Specifically, when running in a UTF\-8 locale,
the Linux console emulator and the GNU screen program ignore these.
Ncurses checks the \fITERM\fP environment variable for these.
For other special cases, you should set this environment variable.
Doing this tells ncurses to use Unicode values which correspond to
the VT100 line-drawing glyphs.
That works for the special cases cited,
and is likely to work for terminal emulators.
.PP
When setting this variable, you should set it to a nonzero value.
Setting it to zero (or to a nonnumber)
disables the special check for \*(``linux\*('' and \*(``screen\*(''.
.PP
As an alternative to the environment variable,
ncurses checks for an extended terminfo capability \fBU8\fP.
This is a numeric capability which can be compiled using \fB@TIC@\ \-x\fP.
For example
.PP
.RS 3
.EX
# 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,
.EE
.RE
.PP
The name \*(``U8\*('' is chosen to be two characters,
to permit it to be used by applications that use ncurses'
termcap interface.
.SS \fINCURSES_TRACE\fP
During initialization, the \fBncurses\fP debugging library
checks the \fI\%NCURSES_TRACE\fP environment variable.
If it is defined, to a numeric value, \fBncurses\fP calls the \fBtrace\fP
function, using that value as the argument.
.PP
The argument values, which are defined in \fBcurses.h\fP, provide several
types of information.
When running with traces enabled, your application will write the
file \fBtrace\fP to the current directory.
.PP
See \fBcurs_trace\fP(3X) for more information.
.SS \fITERM\fP
Denotes your terminal type.
Each terminal type is distinct, though many are similar.
.PP
\fITERM\fP is commonly set by terminal emulators to help
applications find a workable terminal description.
Some of those choose a popular approximation, e.g.,
\*(``ansi\*('', \*(``vt100\*('', \*(``xterm\*('' rather than an exact fit.
Not infrequently, your application will have problems with that approach,
e.g., incorrect function-key definitions.
.PP
If you set \fITERM\fP in your environment,
it has no effect on the operation of the terminal emulator.
It only affects the way applications work within the terminal.
Likewise, as a general rule (\fBxterm\fP(1) being a rare exception),
terminal emulators which allow you to
specify \fITERM\fP as a parameter or configuration value do
not change their behavior to match that setting.
.SS \fITERMCAP\fP
If the \fBncurses\fP library has been configured with \fItermcap\fP
support, \fBncurses\fP will check for a terminal's description in
termcap form if it is not available in the terminfo database.
.PP
The \fI\%TERMCAP\fP environment variable contains
either a terminal description (with newlines stripped out),
or a file name telling where the information denoted by
the \fITERM\fP environment variable exists.
In either case, setting it directs \fBncurses\fP to ignore
the usual place for this information, e.g., /etc/termcap.
.SS \fITERMINFO\fP
\fBncurses\fP can be configured to read from multiple terminal databases.
The \fI\%TERMINFO\fP variable overrides the location for
the default terminal database.
Terminal descriptions (in terminal format) are stored in terminal databases:
.bP
Normally these are stored in a directory tree,
using subdirectories named by the first letter of the terminal names therein.
.IP
This is the scheme used in System V, which legacy Unix systems use,
and the \fI\%TERMINFO\fP variable is used by \fIcurses\fP applications
on those
systems to override the default location of the terminal database.
.IP \(bu 4
If \fBncurses\fP is built to use hashed databases,
then each entry in this list may be the path of a hashed database file, e.g.,
.RS 4
.PP
.RS 4
.EX
/usr/share/terminfo.db
.EE
.RE
.PP
rather than
.PP
.RS 4
.EX
/usr/share/terminfo/
.EE
.RE
.PP
The hashed database uses less disk-space and is a little faster than the
directory tree.
However,
some applications assume the existence of the directory tree,
reading it directly
rather than using the terminfo library calls.
.RE
.bP
If \fBncurses\fP is built with a support for reading termcap files
directly, then an entry in this list may be the path of a termcap file.
.IP \(bu 4
If the \fI\%TERMINFO\fP variable begins with
\*(``hex:\*('' or \*(``b64:\*('',
\fBncurses\fP uses the remainder of that variable as a compiled terminal
description.
You might produce the base64 format using \fBinfocmp\fP(1M):
.RS 4
.PP
.RS 4
.EX
TERMINFO="$(infocmp \-0 \-Q2 \-q)"
export TERMINFO
.EE
.RE
.PP
The compiled description is used if it corresponds to the terminal identified
by the \fITERM\fP variable.
.RE
.PP
Setting \fI\%TERMINFO\fP is the simplest,
but not the only way to set location of the default terminal database.
The complete list of database locations in order follows:
.RS 3
.bP
the last terminal database to which \fBncurses\fP wrote,
if any, is searched first
.bP
the location specified by the \fI\%TERMINFO\fP environment variable
.bP
$HOME/.terminfo
.bP
locations listed in the \fI\%TERMINFO_DIRS\fP environment variable
.bP
one or more locations whose names are configured and compiled into the
ncurses library, i.e.,
.RS 3
.bP
@TERMINFO_DIRS@ (corresponding to the \fI\%TERMINFO_DIRS\fP variable)
.bP
@TERMINFO@ (corresponding to the \fITERMINFO\fP variable)
.RE
.RE
.SS \fITERMINFO_DIRS\fP
Specifies a list of locations to search for terminal descriptions.
Each location in the list is a terminal database as described in
the section on the \fI\%TERMINFO\fP variable.
The list is separated by colons (i.e., ":") on Unix, semicolons on OS/2 EMX.
.PP
There is no corresponding feature in System V terminfo;
it is an extension developed for \fBncurses\fP.
.SS \fITERMPATH\fP
If \fI\%TERMCAP\fP does not hold a file name then \fBncurses\fP checks
the \fI\%TERMPATH\fP environment variable.
This is a list of filenames separated by spaces or colons (i.e., ":") on Unix,
semicolons on OS/2 EMX.
.PP
If the \fI\%TERMPATH\fP environment variable is not set,
\fBncurses\fP looks in the files
.PP
.RS 4
.EX
/etc/termcap, /usr/share/misc/termcap and $HOME/.termcap,
.EE
.RE
.PP
in that order.
.PP
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:
.PP
.RS 4
.EX
$TERMINFO, $TERMINFO_DIRS, $TERMPATH, as well as $HOME.
.EE
.RE
.SH ALTERNATE CONFIGURATIONS
Several different configurations are possible,
depending on the configure script options used when building \fBncurses\fP.
There are a few main options whose effects are visible to the applications
developer using \fBncurses\fP:
.TP 5
\-\-disable\-overwrite
The standard include for \fBncurses\fP is as noted in \fBSYNOPSIS\fP:
.RS 5
.PP
.RS 4
.EX
\fB#include <curses.h>\fP
.EE
.RE
.PP
This option is used to avoid filename conflicts when \fBncurses\fP
is not the main implementation of curses of the computer.
If \fBncurses\fP is installed disabling overwrite, it puts its headers in
a subdirectory, e.g.,
.PP
.RS 4
.EX
\fB#include <ncurses/curses.h>\fP
.EE
.RE
.PP
It also omits a symbolic link which would allow you to use \fB\-lcurses\fP
to build executables.
.RE
.TP 5
\-\-enable\-widec
The configure script renames the library and
(if the \fB\-\-disable\-overwrite\fP option is used)
puts the header files in a different subdirectory.
All of the library names have a \*(``w\*('' appended to them,
i.e., instead of
.RS 5
.PP
.RS 4
.EX
\fB\-lncurses\fP
.EE
.RE
.PP
you link with
.PP
.RS 4
.EX
\fB\-lncursesw\fP
.EE
.RE
.PP
You must also enable the wide-character features in the header file
when compiling for the wide-character library
to use the extended (wide-character) functions.
The symbol which enables these features has changed since XSI Curses, Issue 4:
.bP
Originally, the wide-character feature required the symbol
\fB_XOPEN_SOURCE_EXTENDED\fP
but that was only valid for XPG4 (1996).
.bP
Later, that was deemed conflicting with \fB_XOPEN_SOURCE\fP defined to 500.
.bP
As of mid-2018,
none of the features in this implementation require a \fB_XOPEN_SOURCE\fP
feature greater than 600.
However, X/Open Curses, Issue 7 (2009) recommends defining it to 700.
.bP
Alternatively, you can enable the feature by defining \fBNCURSES_WIDECHAR\fP
with the caveat that some other header file than \fBcurses.h\fP
may require a specific value for \fB_XOPEN_SOURCE\fP
(or a system-specific symbol).
.PP
The \fBcurses.h\fP file which is installed for the wide-character
library is designed to be compatible with the normal library's header.
Only the size of the \fBWINDOW\fP structure differs, and very few
applications require more than a pointer to \fBWINDOW\fPs.
.PP
If the headers are installed allowing overwrite,
the wide-character library's headers should be installed last,
to allow applications to be built using either library
from the same set of headers.
.RE
.TP 5
\-\-with\-pthread
The configure script renames the library.
All of the library names have a \*(``t\*('' appended to them
(before any \*(``w\*('' added by \fB\-\-enable\-widec\fP).
.IP
The global variables such as \fBLINES\fP are replaced by macros to
allow read-only access.
At the same time, setter-functions are provided to set these values.
Some applications (very few) may require changes to work with this convention.
.TP 5
\-\-with\-shared
.TP
\-\-with\-normal
.TP
\-\-with\-debug
.TP
\-\-with\-profile
The shared and normal (static) library names differ by their suffixes,
e.g., \fBlibncurses.so\fP and \fBlibncurses.a\fP.
The debug and profiling libraries add a \*(``_g\*(''
and a \*(``_p\*('' to the root names respectively,
e.g., \fBlibncurses_g.a\fP and \fBlibncurses_p.a\fP.
.TP 5
\-\-with\-termlib
Low-level functions which do not depend upon whether the library
supports wide-characters, are provided in the tinfo library.
.IP
By doing this, it is possible to share the tinfo library between
wide/normal configurations as well as reduce the size of the library
when only low-level functions are needed.
.IP
Those functions are described in these pages:
.RS
.bP
\fBcurs_extend\fP(3X) \- miscellaneous curses extensions
.bP
\fBcurs_inopts\fP(3X) \- \fBcurses\fP input options
.bP
\fBcurs_kernel\fP(3X) \- low-level \fBcurses\fP routines
.bP
\fBcurs_termattrs\fP(3X) \- \fBcurses\fP environment query routines
.bP
\fBcurs_termcap\fP(3X) \- \fBcurses\fP emulation of termcap
.bP
\fBcurs_terminfo\fP(3X) \- \fBcurses\fP interfaces to terminfo database
.bP
\fBcurs_util\fP(3X) \- miscellaneous \fBcurses\fP utility routines
.RE
.TP 5
\-\-with\-trace
The \fBtrace\fP function normally resides in the debug library,
but it is sometimes useful to configure this in the shared library.
Configure scripts should check for the function's existence rather
than assuming it is always in the debug library.
.SH FILES
.TP
.I @DATADIR@/tabset
tab stop initialization database
.TP
.I \*d
compiled terminal capability database
.SH NOTES
If standard output from a \fBncurses\fP 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.
.PP
See subsection \*(``Header files\*('' below regarding symbols exposed by
inclusion of \fI\%curses.h\fP.
.SH EXTENSIONS
The \fBncurses\fP library can be compiled with an option (\fB\-DUSE_GETCAP\fP)
that falls back to the old-style /etc/termcap file if the terminal setup code
cannot find a terminfo entry corresponding to \fITERM\fP.
Use of this feature
is not recommended, as it essentially includes an entire termcap compiler in
the \fBncurses\fP startup code, at significant cost in core and startup cycles.
.PP
The \fBncurses\fP library includes facilities for capturing mouse events on
certain terminals (including xterm).
See the \fBcurs_mouse\fP(3X)
manual page for details.
.PP
The \fBncurses\fP library includes facilities for responding to window
resizing events, e.g., when running in an xterm.
See the \fBresizeterm\fP(3X)
and \fBwresize\fP(3X) manual pages for details.
In addition, the library may be configured with a \fBSIGWINCH\fP handler.
.PP
The \fBncurses\fP 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 \fBdefine_key\fP(3X)
\fBkey_defined\fP(3X),
and \fBkeyok\fP(3X) manual pages for details.
.PP
The \fBncurses\fP library can exploit the capabilities of terminals which
implement the ISO\-6429 SGR 39 and SGR 49 controls, which allow an application
to reset the terminal to its original foreground and background colors.
From the users' perspective, the application is able to draw colored
text on a background whose color is set independently, providing better
control over color contrasts.
See the \fBdefault_colors\fP(3X) manual page for details.
.PP
The \fBncurses\fP library includes a function for directing application output
to a printer attached to the terminal device.
See the \fBcurs_print\fP(3X) manual page for details.
.SH PORTABILITY
The \fBncurses\fP library is intended to be BASE-level conformant with XSI
Curses.
The EXTENDED XSI Curses functionality
(including color support) is supported.
.PP
A small number of local differences (that is, individual differences between
the XSI Curses and \fBncurses\fP calls) are described in \fBPORTABILITY\fP
sections of the library man pages.
.SS Error checking
In many cases, X/Open Curses is vague about error conditions,
omitting some of the SVr4 documentation.
.PP
Unlike other implementations, this one checks parameters such as pointers
to WINDOW structures to ensure they are not null.
The main reason for providing this behavior is to guard against programmer
error.
The standard interface does not provide a way for the library
to tell an application which of several possible errors were detected.
Relying on this (or some other) extension will adversely affect the
portability of curses applications.
.SS Extensions versus portability
Most of the extensions provided by ncurses have not been standardized.
Some have been incorporated into other implementations, such as
PDCurses or NetBSD curses.
Here are a few to consider:
.bP
The routine \fBhas_key\fP is not part of XPG4, nor is it present in SVr4.
See the \fBcurs_getch\fP(3X) manual page for details.
.bP
The routine \fBslk_attr\fP is not part of XPG4, nor is it present in SVr4.
See the \fBcurs_slk\fP(3X) manual page for details.
.bP
The routines \fBgetmouse\fP, \fBmousemask\fP, \fBungetmouse\fP,
\fBmouseinterval\fP, and \fBwenclose\fP relating to mouse interfacing are not
part of XPG4, nor are they present in SVr4.
See the \fBcurs_mouse\fP(3X) manual page for details.
.bP
The routine \fBmcprint\fP was not present in any previous curses implementation.
See the \fBcurs_print\fP(3X) manual page for details.
.bP
The routine \fBwresize\fP is not part of XPG4, nor is it present in SVr4.
See the \fBwresize\fP(3X) manual page for details.
.bP
The WINDOW structure's internal details can be hidden from application
programs.
See \fBcurs_opaque\fP(3X) for the discussion of \fBis_scrollok\fP, etc.
.bP
This implementation can be configured to provide rudimentary support
for multi-threaded applications.
See \fBcurs_threads\fP(3X) for details.
.bP
This implementation can also be configured to provide a set of functions which
improve the ability to manage multiple screens.
See \fBcurs_sp_funcs\fP(3X) for details.
.SS Padding differences
In historic curses versions, delays embedded in the capabilities \fBcr\fP,
\fBind\fP, \fBcub1\fP, \fBff\fP and \fBtab\fP activated corresponding delay
bits in the Unix tty driver.
In this implementation, all padding is done by sending NUL bytes.
This method is slightly more expensive, but narrows the interface
to the Unix kernel significantly and increases the package's portability
correspondingly.
.SS Header files
The header file \fI\%curses.h\fP itself includes the header files
\fI\%stdio.h\fP and \fI\%unctrl.h\fP.
.PP
X/Open Curses has more to say,
but does not finish the story:
.RS 4
.PP
The inclusion of <curses.h> may make visible all symbols
from the headers <stdio.h>, <term.h>, <termios.h>, and <wchar.h>.
.RE
.PP
Here is a more complete story:
.bP
Starting with BSD curses, all implementations have included <stdio.h>.
.IP
BSD curses included <curses.h> and <unctrl.h> from an internal header
"curses.ext" ("ext" was a short name for \fIexterns\fP).
.IP
BSD curses used <stdio.h> internally (for \fBprintw\fP and \fBscanw\fP),
but nothing in <curses.h> itself relied upon <stdio.h>.
.bP
SVr2 curses added \fBnewterm\fP(3X), which relies upon <stdio.h>.
That is, the function prototype uses \fBFILE\fP.
.IP
SVr4 curses added \fBputwin\fP and \fBgetwin\fP, which also use <stdio.h>.
.IP
X/Open Curses documents all three of these functions.
.IP
SVr4 curses and X/Open Curses do not require the developer to
include <stdio.h> before including <curses.h>.
Both document curses showing <curses.h> as the only required header.
.IP
As a result, standard <curses.h> will always include <stdio.h>.
.bP
X/Open Curses is inconsistent with respect to SVr4 regarding <unctrl.h>.
.IP
As noted in \fBcurs_util\fP(3X), ncurses includes <unctrl.h> from
<curses.h> (like SVr4).
.bP
X/Open's comments about <term.h> and <termios.h> may refer to HP-UX and AIX:
.IP
HP-UX curses includes <term.h> from <curses.h>
to declare \fBsetupterm\fP in curses.h,
but ncurses (and Solaris curses) do not.
.IP
AIX curses includes <term.h> and <termios.h>.
Again, ncurses (and Solaris curses) do not.
.bP
X/Open says that <curses.h> \fImay\fP include <term.h>,
but there is no requirement that it do that.
.IP
Some programs use functions declared in both <curses.h> and <term.h>,
and must include both headers in the same module.
Very old versions of AIX curses required including <curses.h>
before including <term.h>.
.IP
Because ncurses header files include the headers needed to
define datatypes used in the headers,
ncurses header files can be included in any order.
But for portability, you should include <curses.h> before <term.h>.
.bP
X/Open Curses says \fI"may make visible"\fP
because including a header file does not necessarily make all symbols
in it visible (there are ifdef's to consider).
.IP
For instance, in ncurses <wchar.h> \fImay\fP be included if
the proper symbol is defined, and if ncurses is configured for
wide-character support.
If the header is included, its symbols may be made visible.
That depends on the value used for \fB_XOPEN_SOURCE\fP
feature test macro.
.bP
X/Open Curses documents one required header,
in a special case: <stdarg.h> before <curses.h> to prototype
the \fBvw_printw\fP and \fBvw_scanw\fP functions
(as well as the obsolete
the \fBvwprintw\fP and \fBvwscanw\fP functions).
Each of those uses a \fBva_list\fP parameter.
.IP
The two obsolete functions were introduced in SVr3.
The other functions were introduced in X/Open Curses.
In between, SVr4 curses provided for the possibility that
an application might include either <varargs.h> or <stdarg.h>.
Initially, that was done by using \fBvoid*\fP for the \fBva_list\fP
parameter.
Later, a special type (defined in <stdio.h>) was introduced,
to allow for compiler type-checking.
That special type is always available,
because <stdio.h> is always included by <curses.h>.
.IP
None of the X/Open Curses implementations require an application
to include <stdarg.h> before <curses.h> because they either
have allowed for a special type, or (like ncurses) include <stdarg.h>
directly to provide a portable interface.
.SH AUTHORS
Zeyd M. Ben-Halim, Eric S. Raymond, Thomas E. Dickey.
Based on \fIpcurses\fP by Pavel Curtis.
.SH SEE ALSO
\fB\%curs_variables\fP(3X),
\fB\%terminfo\fP(5),
\fB\%user_caps\fP(5)