+'\" t
.\"***************************************************************************
-.\" Copyright 2019,2020 Thomas E. Dickey *
+.\" Copyright 2019-2023,2024 Thomas E. Dickey *
.\" Copyright 2001-2015,2017 Free Software Foundation, Inc. *
.\" *
.\" Permission is hereby granted, free of charge, to any person obtaining a *
.\" authorization. *
.\"***************************************************************************
.\"
-.\" $Id: curs_add_wch.3x,v 1.28 2020/10/17 23:10:38 tom Exp $
-.TH curs_add_wch 3X ""
-.ie \n(.g .ds `` \(lq
-.el .ds `` ``
-.ie \n(.g .ds '' \(rq
-.el .ds '' ''
+.\" $Id: curs_add_wch.3x,v 1.62 2024/04/20 21:20:07 tom Exp $
+.TH curs_add_wch 3X 2024-04-20 "ncurses @NCURSES_MAJOR@.@NCURSES_MINOR@" "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
..
.SH NAME
-\fBadd_wch\fP,
-\fBwadd_wch\fP,
-\fBmvadd_wch\fP,
-\fBmvwadd_wch\fP,
-\fBecho_wchar\fP,
-\fBwecho_wchar\fP \- add a complex character and rendition to a \fBcurses\fR window, then advance the cursor
+\fB\%add_wch\fP,
+\fB\%wadd_wch\fP,
+\fB\%mvadd_wch\fP,
+\fB\%mvwadd_wch\fP,
+\fB\%echo_wchar\fP,
+\fB\%wecho_wchar\fP \-
+add a \fIcurses\fR complex character to a window and advance the cursor
.SH SYNOPSIS
+.nf
+\fB#include <curses.h>
.PP
-\fB#include <curses.h>\fP
-.sp
-.B "int add_wch( const cchar_t *\fIwch\fB );"
-.br
-.B "int wadd_wch( WINDOW *\fIwin\fP, const cchar_t *\fIwch\fB );"
-.br
-.B "int mvadd_wch( int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fB );"
-.br
-.B "int mvwadd_wch( WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fB );"
-.sp
-.B "int echo_wchar( const cchar_t *\fIwch\fB );"
-.br
-.B "int wecho_wchar( WINDOW *\fIwin\fP, const cchar_t *\fIwch\fB );"
-.br
+\fBint add_wch(const cchar_t *\fIwch\fP);
+\fBint wadd_wch(WINDOW *\fIwin\fP, const cchar_t *\fIwch\fP);
+\fBint mvadd_wch(int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fP);
+\fBint mvwadd_wch(WINDOW *\fIwin\fP, int \fIy\fP, int \fIx\fP, const cchar_t *\fIwch\fP);
+.PP
+\fBint echo_wchar(const cchar_t *\fIwch\fP);
+\fBint wecho_wchar(WINDOW *\fIwin\fP, const cchar_t *\fIwch\fP);
+.fi
.SH DESCRIPTION
.SS add_wch
-.PP
The
\fBadd_wch\fP,
\fBwadd_wch\fP,
then any previous character at that location is removed.
A new character specified by \fIwch\fP is
placed at that location with rendition specified by \fIwch\fP.
-The cursor then advances to
-the next spacing character on the screen.
+The cursor then advances after this spacing character,
+to prepare for writing the next character on the screen.
+.IP
+The newly added spacing character is the base of the active complex character.
+Subsequent non-spacing characters can be combined with this base
+until another spacing character is written to the screen,
+or the cursor is moved, e.g., using \fBwmove\fP.
.bP
If \fIwch\fP refers to a non-spacing character,
-all previous characters at that location are preserved.
-The non-spacing characters of \fIwch\fP
-are added to the spacing complex character,
-and the rendition specified by \fIwch\fP is ignored.
+it is appended to the active complex character,
+retaining the previous characters at that location.
+The rendition specified by \fIwch\fP is ignored.
+.IP
+The cursor is not advanced after adding a non-spacing character.
+Subsequent calls to add non-spacing characters will update the same position.
.bP
If the character part of \fIwch\fP is
a tab, newline, backspace or other control character,
-the window is updated and the cursor moves as if \fBaddch\fR were called.
+the window is updated and the cursor moves as if \fBaddch\fP were called.
.SS echo_wchar
-.PP
The \fBecho_wchar\fP
function is functionally equivalent to a call to
\fBadd_wch\fP
followed by a call to
-\fBrefresh\fP(3X).
+\fB\%refresh\fP(3X).
Similarly, the
\fBwecho_wchar\fP
is functionally equivalent to a call to
that only a single character is being output is taken into consideration and,
for non-control characters, a considerable performance gain might be seen
by using the *\fBecho\fP* functions instead of their equivalents.
-.SS Line Graphics
-Like \fBaddch\fP(3X),
+.SS "Line Graphics"
+Like \fB\%addch\fP(3X),
\fBaddch_wch\fP accepts symbols which make it simple to draw lines and other
frequently used special characters.
These symbols correspond to the same VT100 line-drawing set as
-\fBaddch\fP(3X).
+\fB\%addch\fP(3X).
.PP
.TS
-l l l l l
-l l l l l
-_ _ _ _ _
-lw(1.5i) lw5 lw5 lw5 lw20.
-\fBACS\fR \fBUnicode\fP \fBASCII\fR \fBacsc\fP \fBGlyph\fR
-\fBName\fR \fBDefault\fP \fBDefault\fR \fBchar\fP \fBName\fR
-WACS_BLOCK 0x25ae # 0 solid square block
-WACS_BOARD 0x2592 # h board of squares
-WACS_BTEE 0x2534 + v bottom tee
-WACS_BULLET 0x00b7 o ~ bullet
-WACS_CKBOARD 0x2592 : a checker board (stipple)
-WACS_DARROW 0x2193 v . arrow pointing down
-WACS_DEGREE 0x00b0 ' f degree symbol
-WACS_DIAMOND 0x25c6 + ` diamond
-WACS_GEQUAL 0x2265 > > greater-than-or-equal-to
-WACS_HLINE 0x2500 \- q horizontal line
-WACS_LANTERN 0x2603 # i lantern symbol
-WACS_LARROW 0x2190 < , arrow pointing left
-WACS_LEQUAL 0x2264 < y less-than-or-equal-to
-WACS_LLCORNER 0x2514 + m lower left-hand corner
-WACS_LRCORNER 0x2518 + j lower right-hand corner
-WACS_LTEE 0x2524 + t left tee
-WACS_NEQUAL 0x2260 ! | not-equal
-WACS_PI 0x03c0 * { greek pi
-WACS_PLMINUS 0x00b1 # g plus/minus
-WACS_PLUS 0x253c + n plus
-WACS_RARROW 0x2192 > + arrow pointing right
-WACS_RTEE 0x251c + u right tee
-WACS_S1 0x23ba \- o scan line 1
-WACS_S3 0x23bb \- p scan line 3
-WACS_S7 0x23bc \- r scan line 7
-WACS_S9 0x23bd \&_ s scan line 9
-WACS_STERLING 0x00a3 f } pound-sterling symbol
-WACS_TTEE 0x252c + w top tee
-WACS_UARROW 0x2191 ^ \- arrow pointing up
-WACS_ULCORNER 0x250c + l upper left-hand corner
-WACS_URCORNER 0x2510 + k upper right-hand corner
-WACS_VLINE 0x2502 | x vertical line
+Lb Lb Lb Lb Lb
+Lb Lb Lb Lb Lb
+Lb L L L Lx.
+\& Unicode ASCII acsc \&
+ACS Name Default Default Char Glyph Name
+_
+WACS_BLOCK 0x25ae # 0 T{
+solid square block
+T}
+WACS_BOARD 0x2592 # h board of squares
+WACS_BTEE 0x2534 + v bottom tee
+WACS_BULLET 0x00b7 o ~ bullet
+WACS_CKBOARD 0x2592 : a T{
+checker board (stipple)
+T}
+WACS_DARROW 0x2193 v . T{
+arrow pointing down
+T}
+WACS_DEGREE 0x00b0 ' f degree symbol
+WACS_DIAMOND 0x25c6 + \(ga diamond
+WACS_GEQUAL 0x2265 > > T{
+greater-than-or-equal-to
+T}
+WACS_HLINE 0x2500 \- q horizontal line
+WACS_LANTERN 0x2603 # i lantern symbol
+WACS_LARROW 0x2190 < , T{
+arrow pointing left
+T}
+WACS_LEQUAL 0x2264 < y T{
+less-than-or-equal-to
+T}
+WACS_LLCORNER 0x2514 + m T{
+lower left-hand corner
+T}
+WACS_LRCORNER 0x2518 + j T{
+lower right-hand corner
+T}
+WACS_LTEE 0x2524 + t left tee
+WACS_NEQUAL 0x2260 ! | not-equal
+WACS_PI 0x03c0 * { greek pi
+WACS_PLMINUS 0x00b1 # g plus/minus
+WACS_PLUS 0x253c + n plus
+WACS_RARROW 0x2192 > + T{
+arrow pointing right
+T}
+WACS_RTEE 0x251c + u right tee
+WACS_S1 0x23ba \- o scan line 1
+WACS_S3 0x23bb \- p scan line 3
+WACS_S7 0x23bc \- r scan line 7
+WACS_S9 0x23bd \&_ s scan line 9
+WACS_STERLING 0x00a3 f } T{
+pound-sterling symbol
+T}
+WACS_TTEE 0x252c + w top tee
+WACS_UARROW 0x2191 ^ \- T{
+arrow pointing up
+T}
+WACS_ULCORNER 0x250c + l T{
+upper left-hand corner
+T}
+WACS_URCORNER 0x2510 + k T{
+upper right-hand corner
+T}
+WACS_VLINE 0x2502 | x vertical line
.TE
.PP
-The wide-character configuration of ncurses also defines symbols
+The wide-character configuration of \fI\%ncurses\fP also defines symbols
for thick lines (\fBacsc\fP \*(``J\*('' to \*(``V\*(''):
+.PP
.TS
-l l l l l
-l l l l l
-_ _ _ _ _
-lw(1.5i) lw5 lw5 lw5 lw20.
-\fBACS\fR \fBUnicode\fP \fBASCII\fR \fBacsc\fP \fBGlyph\fR
-\fBName\fR \fBDefault\fP \fBDefault\fR \fBchar\fP \fBName\fR
-WACS_T_BTEE 0x253b + V thick tee pointing up
-WACS_T_HLINE 0x2501 - Q thick horizontal line
-WACS_T_LLCORNER 0x2517 + M thick lower left corner
-WACS_T_LRCORNER 0x251b + J thick lower right corner
-WACS_T_LTEE 0x252b + T thick tee pointing right
-WACS_T_PLUS 0x254b + N thick large plus
-WACS_T_RTEE 0x2523 + U thick tee pointing left
-WACS_T_TTEE 0x2533 + W thick tee pointing down
-WACS_T_ULCORNER 0x250f + L thick upper left corner
-WACS_T_URCORNER 0x2513 + K thick upper right corner
-WACS_T_VLINE 0x2503 | X thick vertical line
+Lb Lb Lb Lb Lb
+Lb Lb Lb Lb Lb
+Lb L L L Lx.
+\& Unicode ASCII acsc \&
+ACS Name Default Default Char Glyph Name
+_
+WACS_T_BTEE 0x253b + V T{
+thick tee pointing up
+T}
+WACS_T_HLINE 0x2501 - Q T{
+thick horizontal line
+T}
+WACS_T_LLCORNER 0x2517 + M T{
+thick lower left corner
+T}
+WACS_T_LRCORNER 0x251b + J T{
+thick lower right corner
+T}
+WACS_T_LTEE 0x252b + T T{
+thick tee pointing right
+T}
+WACS_T_PLUS 0x254b + N T{
+thick large plus
+T}
+WACS_T_RTEE 0x2523 + U T{
+thick tee pointing left
+T}
+WACS_T_TTEE 0x2533 + W T{
+thick tee pointing down
+T}
+WACS_T_ULCORNER 0x250f + L T{
+thick upper left corner
+T}
+WACS_T_URCORNER 0x2513 + K T{
+thick upper right corner
+T}
+WACS_T_VLINE 0x2503 | X T{
+thick vertical line
+T}
.TE
.PP
and for double-lines (\fBacsc\fP \*(``A\*('' to \*(``I\*(''):
.PP
.TS
-l l l l l
-l l l l l
-_ _ _ _ _
-lw(1.5i) lw5 lw5 lw5 lw20.
-\fBACS\fR \fBUnicode\fP \fBASCII\fR \fBacsc\fP \fBGlyph\fR
-\fBName\fR \fBDefault\fP \fBDefault\fR \fBchar\fP \fBName\fR
-WACS_D_BTEE 0x2569 + H double tee pointing up
-WACS_D_HLINE 0x2550 - R double horizontal line
-WACS_D_LLCORNER 0x255a + D double lower left corner
-WACS_D_LRCORNER 0x255d + A double lower right corner
-WACS_D_LTEE 0x2560 + F double tee pointing right
-WACS_D_PLUS 0x256c + E double large plus
-WACS_D_RTEE 0x2563 + G double tee pointing left
-WACS_D_TTEE 0x2566 + I double tee pointing down
-WACS_D_ULCORNER 0x2554 + C double upper left corner
-WACS_D_URCORNER 0x2557 + B double upper right corner
-WACS_D_VLINE 0x2551 | Y double vertical line
+Lb Lb Lb Lb Lb
+Lb Lb Lb Lb Lb
+Lb L L L Lx.
+\& Unicode ASCII acsc \&
+ACS Name Default Default Char Glyph Name
+_
+WACS_D_BTEE 0x2569 + H T{
+double tee pointing up
+T}
+WACS_D_HLINE 0x2550 - R T{
+double horizontal line
+T}
+WACS_D_LLCORNER 0x255a + D T{
+double lower left corner
+T}
+WACS_D_LRCORNER 0x255d + A T{
+double lower right corner
+T}
+WACS_D_LTEE 0x2560 + F T{
+double tee pointing right
+T}
+WACS_D_PLUS 0x256c + E T{
+double large plus
+T}
+WACS_D_RTEE 0x2563 + G T{
+double tee pointing left
+T}
+WACS_D_TTEE 0x2566 + I T{
+double tee pointing down
+T}
+WACS_D_ULCORNER 0x2554 + C T{
+double upper left corner
+T}
+WACS_D_URCORNER 0x2557 + B T{
+double upper right corner
+T}
+WACS_D_VLINE 0x2551 | Y T{
+double vertical line
+T}
.TE
.PP
-Unicode's descriptions for these characters differs slightly from ncurses,
+Unicode's descriptions for these characters differs slightly from
+\fI\%ncurses\fP,
by introducing the term \*(``light\*('' (along with less important details).
Here are its descriptions for the normal, thick, and double horizontal lines:
.bP
.bP
U+2550 BOX DRAWINGS DOUBLE HORIZONTAL
.SH RETURN VALUE
+All routines return the integer \fBERR\fP upon failure and \fBOK\fP on success.
.PP
-All routines return the integer \fBERR\fR upon failure and \fBOK\fR on success.
-.PP
-X/Open does not define any error conditions.
+X/Open Curses does not specify any error conditions.
This implementation returns an error
.bP
if the window pointer is null or
.PP
The latter may be due to different causes:
.bP
-If \fBscrollok\fR is not enabled,
+If \fB\%scrollok\fP(3X) is not enabled,
writing a character at the lower right margin succeeds.
-However, an error is returned because
-it is not possible to wrap to a new line
+However,
+an error is returned because it is not possible to wrap to a new line.
.bP
If an error is detected when converting a multibyte character to a sequence
of bytes,
or if it is not possible to add all of the resulting bytes in the window,
an error is returned.
.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.
+Functions prefixed with \*(``mv\*('' first perform cursor movement and
+fail if the position
+.RI ( y ,
+.IR x )
+is outside the window boundaries.
.SH NOTES
-.PP
Note that
\fBadd_wch\fP,
\fBmvadd_wch\fP,
\fBecho_wchar\fP
may be macros.
.SH PORTABILITY
-.PP
-All of these functions are described in the XSI Curses standard, Issue 4.
+These functions are described in X/Open Curses, Issue 4.
The defaults specified for line-drawing characters apply in the POSIX locale.
-.PP
+.SS "WACS Symbols"
X/Open Curses makes it clear that the WACS_ symbols should be defined as
-a pointer to \fBcchar_t\fP data, e.g., in the discussion of \fBborder_set\fR.
+a pointer to \fBcchar_t\fP data, e.g., in the discussion of \fBborder_set\fP.
A few implementations are problematic:
.bP
NetBSD curses defines the symbols as a \fBwchar_t\fP within a \fBcchar_t\fP.
.bP
-HPUX curses equates some of the \fIACS_\fP symbols
-to the analogous \fIWACS_\fP symbols as if the \fIACS_\fP symbols were
+HP-UX curses equates some of the \fBACS_\fP symbols
+to the analogous \fBWACS_\fP symbols as if the \fBACS_\fP symbols were
wide characters.
The misdefined symbols are the arrows
and other symbols which are not used for line-drawing.
.PP
-X/Open Curses does not define symbols for thick- or double-lines.
+X/Open Curses does not specify symbols for thick- or double-lines.
SVr4 curses implementations defined their line-drawing symbols in
terms of intermediate symbols.
This implementation extends those symbols, providing new definitions
with their corresponding line-drawing characters.
X/Open Curses did not address the aspect of integrating Unicode with
line-drawing characters.
-Existing implementations of Unix curses (AIX, HPUX, Solaris)
+Existing implementations of Unix curses (AIX, HP-UX, Solaris)
use only the \fBacsc\fP character-mapping to provide this feature.
As a result, those implementations can only use single-byte line-drawing
characters.
-Ncurses 5.3 (2002) provided a table of Unicode values to solve these problems.
+\fI\%ncurses\fP 5.3 (2002) provided a table of Unicode values to solve
+these problems.
NetBSD curses incorporated that table in 2010.
.PP
In this implementation, the Unicode values are used instead of the
-terminal description's \fBacsc\fP mapping as discussed in ncurses(3X)
-for the environment variable \fBNCURSES_NO_UTF8_ACS\fP.
+terminal description's \fBacsc\fP mapping as discussed in
+\fB\%ncurses\fP(3X) for the environment variable
+\fINCURSES_NO_UTF8_ACS\fP.
In contrast, for the same cases, the line-drawing characters
-described in \fBcurs_addch\fP(3X) will use only the ASCII default values.
+described in \fB\%addch\fP(3X) will use only the ASCII default values.
.PP
Having Unicode available does not solve all of the problems with
line-drawing for curses:
\[u2327] U+2327 (x in a rectangle),
\[u256C] U+256C (forms double vertical and horizontal), and
\[u2612] U+2612 (ballot box with x).
+.SS "Complex Characters"
+The complex character type \fBcchar_t\fR
+can store more than one wide character (\fBwchar_t\fR).
+The X/Open Curses description does not mention this possibility,
+describing only the cases where \fIwch\fP is a spacing character
+or a non-spacing character.
+.PP
+This implementation assumes that \fIwch\fP is constructed using
+\fB\%setcchar\fP(3X), and in turn that the result
+.bP
+contains at most one spacing character in the beginning of its list of wide
+characters,
+and zero or more non-spacing characters
+or
+.bP
+may hold one non-spacing character.
+.PP
+In the latter case,
+\fI\%ncurses\fP adds the non-spacing character to the active
+(base) spacing character.
+.SS TABSIZE
+The
+.B TABSIZE
+variable is implemented in SVr4 and other versions of
+.IR curses ,
+but is not specified by X/Open Curses
+(see \fBcurs_variables\fP(3X)).
.SH SEE ALSO
-.na
+\fB\%curs_addch\fP(3X) describes comparable functions of the
+.I \%ncurses
+library in its non-wide-character configuration.
.PP
-\fBcurses\fR(3X),
-\fBcurs_addch\fR(3X),
-\fBcurs_attr\fR(3X),
-\fBcurs_clear\fR(3X),
-\fBcurs_outopts\fR(3X),
-\fBcurs_refresh\fR(3X),
-\fBputwc\fR(3)
+\fB\%curses\fP(3X),
+\fB\%curs_addwstr\fP(3X),
+\fB\%curs_add_wchstr\fP(3X),
+\fB\%curs_attr\fP(3X),
+\fB\%curs_clear\fP(3X),
+\fB\%curs_getcchar\fP(3X),
+\fB\%curs_outopts\fP(3X),
+\fB\%curs_refresh\fP(3X),
+\fB\%curs_variables\fP(3X),
+\fB\%putwc\fP(3)
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