Adding upstream version 4.22.0.upstream/4.22.0

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1800 insertions, 0 deletions

diff --git a/upstream/fedora-40/man3/ncurses.3x b/upstream/fedora-40/man3/ncurses.3x
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+'\" t
+.\"***************************************************************************
+.\" Copyright 2018-2023,2024 Thomas E. Dickey                                *
+.\" Copyright 1998-2015,2017 Free Software Foundation, Inc.                  *
+.\"                                                                          *
+.\" Permission is hereby granted, free of charge, to any person obtaining a  *
+.\" copy of this software and associated documentation files (the            *
+.\" "Software"), to deal in the Software without restriction, including      *
+.\" without limitation the rights to use, copy, modify, merge, publish,      *
+.\" distribute, distribute with modifications, sublicense, and/or sell       *
+.\" copies of the Software, and to permit persons to whom the Software is    *
+.\" furnished to do so, subject to the following conditions:                 *
+.\"                                                                          *
+.\" The above copyright notice and this permission notice shall be included  *
+.\" in all copies or substantial portions of the Software.                   *
+.\"                                                                          *
+.\" THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS  *
+.\" OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF               *
+.\" MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.   *
+.\" IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,   *
+.\" DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR    *
+.\" OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR    *
+.\" THE USE OR OTHER DEALINGS IN THE SOFTWARE.                               *
+.\"                                                                          *
+.\" Except as contained in this notice, the name(s) of the above copyright   *
+.\" holders shall not be used in advertising or otherwise to promote the     *
+.\" sale, use or other dealings in this Software without prior written       *
+.\" authorization.                                                           *
+.\"***************************************************************************
+.\"
+.\" $Id: ncurses.3x,v 1.197 2024/01/13 20:30:39 tom Exp $
+.TH ncurses 3X 2024-01-13 "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 /usr/share/terminfo
+.SH NAME
+\fB\%ncurses\fP \-
+character-cell terminal interface with optimized output
+.SH SYNOPSIS
+.nf
+\fB#include <curses.h>
+.fi
+.SH DESCRIPTION
+The \fI\%ncurses\fP library routines give the user a
+terminal-independent method of updating character screens with
+reasonable optimization.
+This implementation is \*(``new curses\*('' (\fI\%ncurses\fP) and
+is the approved replacement for
+4.4BSD classic curses, which has been discontinued.
+This describes \fI\%ncurses\fP
+version 6.4 (patch 20240127).
+.PP
+The \fI\%ncurses\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 \fI\%ncurses\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 exclusive of a function definition
+(which prevents its address from being taken).
+This section also describes implementation details that will be
+significant to the programmer but which are not standardized.
+.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 section \*(``ALTERNATE CONFIGURATIONS\*('' below.
+.PP
+The \fI\%ncurses\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 \fBtput 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 Overview
+A
+.I curses
+library abstracts the terminal screen by representing all or part of it
+as a
+.I \%WINDOW
+data structure.
+A
+.I window
+is a rectangular grid of character cells,
+addressed by row and column coordinates
+.RI ( y ,
+.IR x ),
+with the upper left corner as (0, 0).
+A window called \fB\%stdscr\fP,
+the same size as the terminal screen,
+is always available.
+Create others with \fB\%newwin\fP(3X).
+.PP
+A
+.I curses
+library does not manage overlapping windows.
+(See \fBpanel\fP(3X) if you desire this.)
+You can either use \fB\%stdscr\fP to manage one screen-filling window,
+or tile the screen into non-overlapping windows and not use
+\fB\%stdscr\fP at all.
+Mixing the two approaches will result in unpredictable,
+and undesired,
+effects.
+.PP
+Functions permit manipulation of a window and the
+.I cursor
+identifying the cell within it at which the next output operation will
+occur.
+Among those,
+the most basic are \fBmove\fP(3X) and \fB\%addch\fP(3X):
+these place the cursor and write a character to
+.BR \%stdscr ,
+respectively.
+As a rule,
+window-addressing functions feature names prefixed
+(or infixed,
+see below)
+with \*(``w\*('';
+these allow the user to specify a pointer to a
+.I \%WINDOW.
+Counterparts not thus prefixed
+(or infixed)
+affect \fB\%stdscr\fP.
+Because moving the cursor prior to another operation is so common,
+.I curses
+generally also provides functions with a \*(``mv\*('' prefix as a
+convenience.
+Thus,
+the library defines all of
+\fB\%addch\fP,
+\fB\%waddch\fP,
+\fB\%mvaddch\fP,
+and
+\fB\%mvwaddch\fP.
+When both prefixes are present,
+the order of arguments is a
+.I \%WINDOW
+pointer first,
+then a
+.I y
+and
+.I x
+coordinate pair.
+.PP
+Updating the terminal screen with every
+.I curses
+call can cause unpleasant flicker or inefficient use of the
+communications channel to the device.
+Therefore,
+after using
+.I curses
+functions to accumulate a set of desired updates that make sense to
+present together,
+call \fB\%refresh\fP(3X) to tell the library to make the user's screen
+look like \fBstdscr\fP.
+.I \%ncurses
+.\" X/Open Curses Issue 7 assumes some optimization will be done, but
+.\" does not mandate it in any way.
+.I optimizes
+its output by computing a minimal number of operations to mutate the
+screen from its state at the previous refresh to the new one.
+Effective optimization demands accurate information about the terminal
+device:
+the management of such information is the province of the
+\fB\%terminfo\fP(3X) API,
+a feature of every standard
+.I curses
+implementation.
+.PP
+Special windows called \fIpads\fP may also be manipulated.
+These are windows that are not constrained to the size of the terminal
+screen and whose contents need not be completely displayed.
+See \fB\%curs_pad\fP(3X).
+.PP
+In addition to drawing characters on the screen,
+rendering attributes and colors may be supported,
+causing the characters to show up in such modes as underlined,
+in reverse video,
+or in color on terminals that support such display enhancements.
+See \fB\%curs_attr\fP(3X).
+.PP
+.I curses
+predefines constants for a small set of line-drawing and other graphics
+corresponding to the DEC Alternate Character Set (ACS),
+a feature of VT100 and other terminals.
+See
+\fB\%waddch\fP(3X) and
+\fB\%wadd_wch\fP(3X).
+.PP
+.I curses
+is implemented using the operating system's terminal driver;
+keystroke events are received not as scan codes but as byte sequences.
+Graphical keycaps
+(alphanumeric and punctuation keys,
+and the space)
+appear as-is.
+Everything else,
+including the tab,
+enter/return,
+keypad,
+arrow,
+and function keys,
+appears as a control character or a multibyte
+.I "escape sequence."
+.I curses
+translates these into unique
+.I "key codes."
+See \fB\%getch\fP(3X).
+.SS "Effects of GUIs and Environment Variables"
+The selection of an appropriate value of
+.I TERM
+in the process environment is essential to correct
+.I curses
+and
+.I \%term\%info
+library operation.
+A well-configured system selects a correct
+.I TERM
+value automatically;
+\fB\%tset\fP(1) may assist with troubleshooting exotic situations.
+.PP
+If the environment variables \fILINES\fP and \fI\%COLUMNS\fP are set,
+or if the
+.I curses
+program is executing in a graphical windowing environment,
+the information obtained thence overrides that obtained by
+.IR \%term\%info .
+An
+.I \%ncurses
+extension supports resizable terminals;
+see \fB\%wresize\fP(3X).
+.PP
+If the environment variable \fI\%TERMINFO\fP is defined,
+a
+.I curses
+program checks first for a terminal type description in the location it
+identifies.
+.I \%TERMINFO
+is useful for developing experimental type descriptions or when write
+permission to \fI\*d\fP is not available.
+.PP
+See section \*(``ENVIRONMENT\*('' below.
+.SS "Naming Conventions"
+Many
+.I curses
+functions have two or more versions.
+Those prefixed with \*(``w\*('' require a window argument.
+Four functions prefixed with \*(``p\*('' require a pad argument.
+Those without a prefix generally operate on \fB\%stdscr\fP.
+.PP
+In function synopses,
+.I \%ncurses
+man pages apply the following names to parameters.
+.PP
+.TS
+center;
+Li L.
+bf	\fIbool\fP (\fBTRUE\fP or \fBFALSE\fP)
+win	pointer to \fIWINDOW\fP
+pad	pointer to \fIWINDOW\fP that is a pad
+.TE
+.SS "Wide and Non-wide Character Configurations"
+This manual page describes functions that appear in any configuration
+of the library.
+There are two common configurations;
+see section \*(``ALTERNATE CONFIGURATIONS\*('' below.
+.TP 10 \" "ncursesw" + 2n
+.I \%ncurses
+is the library in its \*(``non-wide\*('' configuration,
+handling only eight-bit characters.
+It stores a character combined with attributes in a
+.I \%chtype
+datum,
+which is often an alias of
+.I int.
+.IP
+Attributes alone
+(with no corresponding character)
+can be stored in variables of
+.I \%chtype
+or
+.I \%attr_t
+type.
+In either case,
+they are represented as an integral bit mask.
+.IP
+Each cell of a
+.I \%WINDOW
+is stored as a
+.I \%chtype.
+.TP 10
+.I \%ncursesw
+is the library in its \*(``wide\*('' configuration,
+which handles character encodings requiring a larger data type than
+.I \%char
+(a byte-sized type)
+can represent.
+It adds about one third more calls using additional data types that
+can store such
+.I multibyte
+characters.
+.RS 10 \" same as foregoing tag width
+.TP 9 \" "cchar_t" + 2n
+.I \%cchar_t
+corresponds to the non-wide configuration's
+.I \%chtype.
+It always a structure type,
+because it stores more data than fits into an integral type.
+A character code may not be representable as a
+.I \%char,
+and moreover more than one character may occupy a cell
+(as with accent marks and other diacritics).
+Each character is of type
+.I \%wchar_t;
+a complex character contains one spacing character and zero or more
+non-spacing characters
+(see below).
+Attributes and color data are stored in separate fields of the
+structure,
+not combined as in
+.I \%chtype.
+.PP
+Each cell of a
+.I \%WINDOW
+is stored as a
+.I \%cchar_t.
+.PP
+The \fB\%setcchar\fP(3X) and \fB\%getcchar\fP(3X)
+functions store and retrieve the data from a
+.I \%cchar_t
+structure.
+The wide library API of
+.I \%ncurses
+depends on two data types standardized by ISO C95.
+.TP 9
+.I \%wchar_t
+stores a wide character.
+Like
+.I \%chtype,
+it may be an alias of
+.I int.
+Depending on the character encoding,
+a wide character may be
+.I spacing,
+meaning that it occupies a character cell by itself and typically
+accompanies cursor advancement,
+or
+.I 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.
+.TP 9
+.I \%wint_t
+can store a
+.I \%wchar_t
+or the constant
+.BR \%WEOF ,
+analogously to the
+.IR int -sized
+character manipulation functions of ISO C and its constant
+.BR \%EOF .
+.RE
+.IP
+The wide library provides additional functions that complement those in
+the non-wide library where the size of the underlying character type is
+significant.
+A somewhat regular naming convention relates many of the wide variants
+to their non-wide counterparts;
+where a non-wide function name contains \*(``ch\*('' or \*(``str\*('',
+prefix it with \*(``_w\*('' to obtain the wide counterpart.
+For example,
+\fB\%waddch\fP becomes \fB\%wadd_wch\fP.
+.IP
+This convention is inapplicable to some non-wide function names,
+so other transformations are used for the wide configuration:
+in the window background management functions,
+\*(``bkgd\*('' becomes \*(``bkgrnd\*('';
+the window border-drawing and -clearing functions are suffixed with
+\*(``_set\*(''.
+.\"
+.SS "Function Name Index"
+The following table lists the
+.I curses
+functions provided in the non-wide and wide APIs and the corresponding
+man pages that describe them.
+Those flagged with \*(``*\*(''
+are
+.IR \%ncurses -specific,
+neither described by X/Open Curses nor present in SVr4.
+.PP
+.TS
+center tab(/);
+l l .
+\f(BIcurses\fP Function Name/Man Page
+_
+COLOR_PAIR/\fBcurs_color\fP(3X)
+PAIR_NUMBER/\fBcurs_color\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
+Unless otherwise noted,
+functions that return an integer return \fBOK\fP on success and
+\fBERR\fP on failure.
+Functions that return pointers return \fBNULL\fP on failure.
+Typically,
+.I \%ncurses
+treats a null pointer passed as a function parameter as a failure.
+.PP
+Functions with a \*(``mv\*('' prefix first perform cursor movement using
+\fB\%wmove\fP and fail if the position is outside the window,
+or
+(for \*(``mvw\*('' functions)
+if the
+.I \%WINDOW
+pointer is null.
+.SH ENVIRONMENT
+The following environment symbols are useful for customizing the
+runtime behavior of the \fI\%ncurses\fP library.
+The most important ones have been already discussed in detail.
+.SS "\fICC\fP (command character)"
+When set,
+change the
+.B \%command_character
+.RB ( \%cmdch )
+capability value of loaded
+.I \%term\%info
+entries to the value of this variable.
+Very few
+.I \%term\%info
+entries provide this feature.
+.PP
+Because this name is also used in development environments to represent
+the C compiler's name,
+\fI\%ncurses\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, \fI\%ncurses\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,
+\fI\%ncurses\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 \fI\%ncurses\fP 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 \fI\%ncurses\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, \fI\%ncurses\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 \fI\%ncurses\fP 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 \fI\%ncurses\fP.
+.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 \fI\%ncurses\fP 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,
+\fI\%ncurses\fP will attempt to open GPM if \fITERM\fP contains
+\*(``linux\*(''.
+.SS "\fINCURSES_NO_HARD_TABS\fP"
+\fI\%ncurses\fP may use tabs as part of cursor movement optimization.
+In some cases,
+your terminal driver may not handle these properly.
+Set this environment variable to any value 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 to any value.
+.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
+\fI\%ncurses\fP enabled buffered output during terminal initialization.
+This was done (as in SVr4 curses) for performance reasons.
+For testing purposes, both of \fI\%ncurses\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,
+\fI\%ncurses\fP 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 \fI\%stdio\fP(3) calls with \fI\%ncurses\fP calls and (usually)
+work.
+This is no longer possible since \fI\%ncurses\fP 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 \fI\%ncurses\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.
+\fI\%ncurses checks the \fITERM\fP environment variable for these.
+For other special cases, you should set this environment variable.
+Doing this tells \fI\%ncurses\fP 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,
+\fI\%ncurses\fP checks for an extended terminfo capability \fBU8\fP.
+This is a numeric capability which can be compiled using \fBtic\ \-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 \fI\%ncurses\fP'
+termcap interface.
+.SS "\fINCURSES_TRACE\fP"
+During initialization, the \fI\%ncurses\fP debugging library
+checks the \fI\%NCURSES_TRACE\fP environment variable.
+If it is defined,
+to a numeric value,
+\fI\%ncurses\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 \fI\%ncurses\fP library has been configured with \fItermcap\fP
+support, \fI\%ncurses\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 \fI\%ncurses\fP to ignore
+the usual place for this information, e.g., /etc/termcap.
+.SS "\fITERMINFO\fP"
+\fI\%ncurses\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 \fI\%ncurses\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 \fI\%ncurses\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:\*('',
+\fI\%ncurses\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="$(infocmp \-0 \-Q2 \-q)"
+export TERMINFO
+.EE
+.RE
+.PP
+The compiled description is used if it corresponds to the terminal identified
+by the \fITERM\fP variable.
+.RE
+.PP
+Setting \fI\%TERMINFO\fP is the simplest,
+but not the only way to set location of the default terminal database.
+The complete list of database locations in order follows:
+.RS 3
+.bP
+the last terminal database to which \fI\%ncurses\fP wrote,
+if any, is searched first
+.bP
+the location specified by the \fI\%TERMINFO\fP environment variable
+.bP
+$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
+\fI\%ncurses\fP library, i.e.,
+.RS 3
+.bP
+/etc/terminfo:/usr/share/terminfo (corresponding to the \fI\%TERMINFO_DIRS\fP variable)
+.bP
+/usr/share/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 \fI\%ncurses\fP.
+.SS "\fITERMPATH\fP"
+If \fI\%TERMCAP\fP does not hold a file name then \fI\%ncurses\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,
+\fI\%ncurses\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"
+Many different
+.I \%ncurses
+configurations are possible,
+determined by the options given to the
+.I \%configure
+script when building the library.
+Run the script with the
+.B \-\-help
+option to peruse them all.
+A few are of particular significance to the application developer
+employing
+.I \%ncurses.
+.TP 5
+\-\-disable\-overwrite
+The standard include for \fI\%ncurses\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 \fI\%ncurses\fP
+is not the main implementation of curses of the computer.
+If \fI\%ncurses\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 \fI\%curses.h\fP 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 \fI\%WINDOW\fP structure differs;
+few applications require more than pointers to \fI\%WINDOW\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
+\fB\%curs_extend\fP(3X) \- miscellaneous \fIcurses\fP extensions
+.bP
+\fB\%curs_inopts\fP(3X) \- \fIcurses\fP input options
+.bP
+\fB\%curs_kernel\fP(3X) \- low-level \fIcurses\fP routines
+.bP
+\fB\%curs_termattrs\fP(3X) \- \fIcurses\fP environment query routines
+.bP
+\fB\%curs_termcap\fP(3X) \- \fIcurses\fP emulation of \fItermcap\fP
+.bP
+\fB\%curs_terminfo\fP(3X) \- \fIcurses\fP interface to \fIterminfo\fP
+database
+.bP
+\fB\%curs_util\fP(3X) \- miscellaneous \fIcurses\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 /usr/share/tabset
+tab stop initialization database
+.TP
+.I \*d
+compiled terminal capability database
+.SH NOTES
+X/Open Curses permits most functions it specifies to be made available
+as macros as well.
+.\" See X/Open Curses Issue 4, Version 2, pp. 227-234.
+.\" See X/Open Curses Issue 7, pp. 311-318.
+\fI\%ncurses\fP does so
+.bP
+for functions that return values via their parameters,
+.bP
+to support obsolete features,
+.bP
+to reuse functions
+(for example,
+those that move the cursor before another operation),
+and
+.bP
+a few special cases.
+.PP
+If the standard output file descriptor of an
+.I \%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.
+.PP
+See subsection \*(``Header files\*('' below regarding symbols exposed by
+inclusion of \fI\%curses.h\fP.
+.SH EXTENSIONS
+.I \%ncurses
+enables an application to capture mouse events on certain terminals,
+including
+.I \%xterm;
+see \fB\%curs_mouse\fP(3X).
+.PP
+.I \%ncurses
+provides a means of responding to window resizing events,
+as when running in a GUI terminal emulator application such as
+.I \%xterm;
+see \fB\%resizeterm\fP(3X) and \fB\%wresize\fP(3X).
+.PP
+.I \%ncurses
+allows an application to query the terminal for the presence of a wide
+variety of special keys;
+see \fB\%has_key\fP(3X).
+.PP
+.I \%ncurses
+extends the fixed set of function key capabilities specified by X/Open
+Curses by allowing the application programmer to define additional key
+sequences at runtime;
+see
+\fB\%define_key\fP(3X),
+\fB\%key_defined\fP(3X),
+and
+\fB\%keyok\fP(3X).
+.PP
+.I \%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 \fB\%default_colors\fP(3X).
+.PP
+An
+.I \%ncurses
+application can choose to hide the internal details of
+.I \%WINDOW
+structures,
+instead using accessor functions such as
+\fB\%is_scrollok\fP(3X).
+.PP
+.I \%ncurses
+enables an application to direct application output to a printer
+attached to the terminal device;
+see \fB\%curs_print\fP(3X).
+.PP
+.I \%ncurses
+offers \fB\%slk_attr\fP(3X) as a counterpart of \fB\%attr_get\fP(3X) for
+soft-label key lines,
+and \fB\%extended_slk_color\fP(3X) as a form of \fB\%slk_color\fP(3X)
+that can gather color information from them when many colors are
+supported.
+.PP
+Some extensions are only available if
+.I \%ncurses
+is compiled to support them;
+see section \*(``ALTERNATE CONFIGURATIONS\*('' above.
+.bP
+Rudimentary support for multi-threaded applications may be available;
+see \fBcurs_threads\fP(3X).
+.bP
+Functions that ease the management of multiple screens can be exposed;
+see \fBcurs_sp_funcs\fP(3X).
+.bP
+The compiler option
+.B \%\-DUSE_GETCAP
+causes the library to fall back to reading
+.I \%/etc/termcap
+if the terminal setup code cannot find a
+.I \%term\%info
+entry corresponding to
+.I TERM.
+Use of this feature is not recommended,
+as it essentially includes an entire
+.I termcap
+compiler in the
+.I \%ncurses
+startup code,
+at a cost in memory usage and application launch latency.
+.PP
+.I \%PDCurses
+and NetBSD
+.I curses
+incorporate some
+.I \%ncurses
+extensions.
+Individual man pages indicate where this is the case.
+.SH PORTABILITY
+X/Open Curses defines two levels of conformance,
+\*(``base\*('' and \*(``enhanced\*(''.
+The latter includes several additional features,
+such as wide-character and color support.
+.I \%ncurses
+intends base-level conformance with X/Open Curses,
+and supports nearly all its enhanced features.
+.\" XXX: What's missing?  GBR counts untic(1), and that's all.
+.PP
+Differences between X/Open Curses and
+.I \%ncurses
+are documented in the \*(``PORTABILITY\*('' sections of applicable 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 \fI\%WINDOW\fP 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 "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
+file
+.I \%curses.ext
+(\*(``ext\*('' abbreviated \*(``externs\*('').
+.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),
+\fI\%ncurses\fP 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 \fI\%ncurses\fP (and Solaris curses) do not.
+.IP
+AIX curses includes <term.h> and <termios.h>.
+Again, \fI\%ncurses\fP (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 \fI\%ncurses\fP header files include the headers needed to
+define datatypes used in the headers,
+\fI\%ncurses\fP 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 \fI\%ncurses\fP <wchar.h> \fImay\fP be included if
+the proper symbol is defined, and if \fI\%ncurses\fP 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 \fI\%ncurses\fP)
+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)