ncurses 6.5 - patch 20240511

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

diff --git a/man/curs_add_wch.3x b/man/curs_add_wch.3x
index b7164ada0e2bd030b62465faae27d1487cefdd76..502425afd354e60214291f8e7676580a8c25235f 100644 (file)
--- a/man/curs_add_wch.3x
+++ b/man/curs_add_wch.3x
@@ -1,5 +1,7 @@
+'\" t

 .\"***************************************************************************
 .\"***************************************************************************

-.\" Copyright (c) 2001-2011,2012 Free Software Foundation, Inc.              *
+.\" 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  *
 .\" copy of this software and associated documentation files (the            *
 .\"                                                                          *
 .\" Permission is hereby granted, free of charge, to any person obtaining a  *
 .\" copy of this software and associated documentation files (the            *


@@ -26,199 +28,514 @@
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"
 .\" authorization.                                                           *
 .\"***************************************************************************
 .\"

-.\" $Id: curs_add_wch.3x,v 1.15 2012/11/03 23:03:59 tom Exp $
-.TH curs_add_wch 3X ""
+.\" $Id: curs_add_wch.3x,v 1.63 2024/05/11 21:31:45 tom Exp $
+.TH curs_add_wch 3X 2024-05-11 "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
 .de bP

-.IP \(bu 4
+.ie n  .IP \(bu 4
+.el    .IP \(bu 2

 ..
 .SH NAME
 ..
 .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, possibly advancing the cursor

 .SH SYNOPSIS
 .SH SYNOPSIS

+.nf
+\fB#include <curses.h>

 .PP
 .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 );"
-.br
-.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
 .SH DESCRIPTION

+.SS wadd_wch
+.B \%wadd_wch
+writes the complex character
+.I wch
+to the window
+.IR win ","
+then may advance the cursor position,
+analogously to the standard C library's \fI\%putwchar\fP(3).
+\fB\%ncurses\fP(3X) describes the variants of this function.

 .PP
 .PP

-The
-\fBadd_wch\fP,
-\fBwadd_wch\fP,
-\fBmvadd_wch\fP, and
-\fBmvwadd_wch\fP
-functions put the complex character \fIwch\fP into the given
-window at its current position,
-which is then advanced.
-These functions perform
-wrapping and special-character processing as follows:
-.bP
-If \fIwch\fP refers to a spacing character,
-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.
-.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.
-.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.
-.PP
-The \fBecho_wchar\fP
-function is functionally equivalent to a call to
-\fBadd_wch\fP
-followed by a call to
-\fBrefresh\fP.
-Similarly, the
-\fBwecho_wchar\fP
-is functionally equivalent to a call to
-\fBwadd_wch\fP
-followed by a call to
-\fBwrefresh\fP.
-The knowledge
-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),
-\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).
+Much behavior depends on whether the wide characters in
+.I wch
+are spacing or non-spacing;
+see subsection \*(``Complex Characters\*('' below.
+.bP
+If
+.I wch
+contains a spacing character,
+then any character at the cursor is first removed.
+The complex character
+.IR wch ","
+with its attributes and color pair identifier,
+becomes the
+.I base
+of the
+.IR "active complex character" "."
+.bP
+If
+.I wch
+contains only non-spacing characters,
+.\" XXX: see wadd_wch_literal (the beginning of the array may be nonspacing)
+they are combined with the active complex character.
+.I curses
+ignores its attributes and color pair identifier,
+and does not advance the cursor.
+.PP
+Further non-spacing characters added with
+.B \%wadd_wch
+are not written at the new cursor position but combine with the active
+complex character until another spacing character is written to the
+window or the cursor is moved.
+.PP
+If advancement occurs at the right margin,
+.bP
+the cursor automatically wraps to the beginning of the next line,
+then,
+.bP
+if it was at the bottom of the scrolling region,
+and if \fB\%scrollok\fP(3X) is enabled for
+.IR win ,
+the scrolling region scrolls up one line.
+.PP
+If
+.I wch
+is a
+backspace,
+carriage return,
+line feed,
+or
+tab,
+the cursor moves appropriately within the window.
+.bP
+Backspace moves the cursor one character left;
+at the left margin of a window,
+it does nothing.
+.bP
+Carriage return moves the cursor to the left margin on the current line
+of the window.
+.bP
+Line feed does a \fB\%clrtoeol\fP(3X),
+then advances as if from the right margin.
+.bP
+Tab advances the cursor to the next tab stop
+(possibly on the next line);
+these are placed at every eighth column by default.
+Alter the tab interval with the
+.B \%TABSIZE
+extension;
+see \fB\%curs_variables\fP(3X).
+.PP
+If
+.I wch
+is any other nonprintable character,
+it is drawn in printable form using the same convention as
+\fB\%wunctrl\fP(3X).
+.PP
+Calling \fB\%win_wch\fP(3X) on the location of a nonprintable character
+does not return the character itself,
+but its \fB\%wunctrl\fP(3X) representation.
+.SS wecho_wchar
+.B \%echo_wchar
+and
+.B \%wecho_wchar
+are equivalent to calling
+.RB \%( w ) add_wch
+followed by
+.RB \%( w ) refresh .
+.I curses
+interprets these functions as a hint that only a single (complex)
+character is being output;
+for non-control characters,
+a considerable performance gain may be enjoyed by employing them.
+.\" TODO: Combine the following with the "Line Drawing" subsection of
+.\" terminfo(5) and replace this with a cross reference there.
+.SS "Forms-Drawing Characters"
+.I curses
+defines macros starting with
+.B \%WACS_
+that can be used with
+.B \%wadd_wch
+to write line-drawing and other special characters to the screen.
+.I \%ncurses
+terms these
+.I "forms-drawing characters."
+The ACS default listed below is used if the
+.B \%acs_chars
+.RB ( \%acsc )
+.I \%term\%info
+capability does not define a terminal-specific replacement for it,
+or if the terminal and locale configuration requires Unicode to access
+these characters but the library is unable to use Unicode.
+The \*(``acsc char\*('' column corresponds to how the characters are
+specified in the
+.B \%acs_chars
+.RB ( \%acsc )
+string capability,
+and the characters in it may appear on the screen if the terminal type's
+database entry incorrectly advertises ACS support.
+The name \*(``ACS\*('' originates in the Alternate Character Set feature
+of the DEC VT100 terminal.

 .PP
 .TS
 .PP
 .TS

-l l l l
-_ _ _ _
-lw(1.5i) lw7 lw7 lw20.
-\fIName\fR     \fIUnicode\fP   \fIDefault\fR   \fIDescription\fR
-WACS_BLOCK     0x25ae  #       solid square block
-WACS_BOARD     0x2592  #       board of squares
-WACS_BTEE      0x2534  +       bottom tee
-WACS_BULLET    0x00b7  o       bullet
-WACS_CKBOARD   0x2592  :       checker board (stipple)
-WACS_DARROW    0x2193  v       arrow pointing down
-WACS_DEGREE    0x00b0  '       degree symbol
-WACS_DIAMOND   0x25c6  +       diamond
-WACS_GEQUAL    0x2265  >       greater-than-or-equal-to
-WACS_HLINE     0x2500  \-      horizontal line
-WACS_LANTERN   0x2603  #       lantern symbol
-WACS_LARROW    0x2190  <       arrow pointing left
-WACS_LEQUAL    0x2264  <       less-than-or-equal-to
-WACS_LLCORNER  0x2514  +       lower left-hand corner
-WACS_LRCORNER  0x2518  +       lower right-hand corner
-WACS_LTEE      0x2524  +       left tee
-WACS_NEQUAL    0x2260  !       not-equal
-WACS_PI        0x03c0  *       greek pi
-WACS_PLMINUS   0x00b1  #       plus/minus
-WACS_PLUS      0x253c  +       plus
-WACS_RARROW    0x2192  >       arrow pointing right
-WACS_RTEE      0x251c  +       right tee
-WACS_S1        0x23ba  \-      scan line 1
-WACS_S3        0x23bb  \-      scan line 3
-WACS_S7        0x23bc  \-      scan line 7
-WACS_S9        0x23bd  \&_     scan line 9
-WACS_STERLING  0x00a3  f       pound-sterling symbol
-WACS_TTEE      0x252c  +       top tee
-WACS_UARROW    0x2191          ^       arrow pointing up
-WACS_ULCORNER  0x250c  +       upper left-hand corner
-WACS_URCORNER  0x2510  +       upper right-hand corner
-WACS_VLINE     0x2502  |       vertical line
+Lb Lb Lb Lb Lb
+Lb Lb Lb Lb Lb
+Lb L  L  L  Lx.
+\&     Unicode ACS     acsc    \&
+Symbol 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
 .TE
 .PP

-The wide-character configuration of ncurses also defines symbols
-for thick- and double-lines:
+The wide-character configuration of \fI\%ncurses\fP also defines symbols
+for thick lines (\fBacsc\fP \*(``J\*('' to \*(``V\*(''):

 .PP
 .TS
 .PP
 .TS

-l l l l
-_ _ _ _
-lw(1.5i) lw7 lw7 lw20.
-\fIName\fR     \fIUnicode\fP   \fIDefault\fR   \fIDescription\fR
-WACS_T_ULCORNER        0x250f  +       thick upper left corner
-WACS_T_LLCORNER        0x2517  +       thick lower left corner
-WACS_T_URCORNER        0x2513  +       thick upper right corner
-WACS_T_LRCORNER        0x251b  +       thick lower right corner
-WACS_T_LTEE    0x252b  +       thick tee pointing right
-WACS_T_RTEE    0x2523  +       thick tee pointing left
-WACS_T_BTEE    0x253b  +       thick tee pointing up
-WACS_T_TTEE    0x2533  +       thick tee pointing down
-WACS_T_HLINE   0x2501  -       thick horizontal line
-WACS_T_VLINE   0x2503  |       thick vertical line
-WACS_T_PLUS    0x254b  +       thick large plus or crossover
-WACS_D_ULCORNER        0x2554  +       double upper left corner
-WACS_D_LLCORNER        0x255a  +       double lower left corner
-WACS_D_URCORNER        0x2557  +       double upper right corner
-WACS_D_LRCORNER        0x255d  +       double lower right corner
-WACS_D_RTEE    0x2563  +       double tee pointing left
-WACS_D_LTEE    0x2560  +       double tee pointing right
-WACS_D_BTEE    0x2569  +       double tee pointing up
-WACS_D_TTEE    0x2566  +       double tee pointing down
-WACS_D_HLINE   0x2550  -       double horizontal line
-WACS_D_VLINE   0x2551  |       double vertical line
-WACS_D_PLUS    0x256c  +       double large plus or crossover
+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
 .TE

-.SH RETURN VALUE

 .PP
 .PP

-All routines return the integer \fBERR\fR upon failure and \fBOK\fR on success.
+and for double-lines (\fBacsc\fP \*(``A\*('' to \*(``I\*(''):

 .PP
 .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.
-.SH NOTES
+.TS
+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
 .PP

-Note that
-\fBadd_wch\fP,
-\fBmvadd_wch\fP,
-\fBmvwadd_wch\fP, and
-\fBecho_wchar\fP
-may be macros.
+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
+U+2500 BOX DRAWINGS LIGHT HORIZONTAL
+.bP
+U+2501 BOX DRAWINGS HEAVY HORIZONTAL
+.bP
+U+2550 BOX DRAWINGS DOUBLE HORIZONTAL
+.SH RETURN VALUE
+These functions return
+.B OK
+on success and
+.B ERR
+on failure.
+In
+.IR \%ncurses ,
+.B \%wadd_wch
+returns
+.B ERR
+if
+.bP
+.I win
+is
+.BR NULL ","
+.bP
+wrapping to a new line is impossible because \fB\%scrollok\fP(3X) has
+not been called on
+.I win
+when writing to its bottom right location is attempted,
+or
+.bP
+it is not possible to add a complete character at the cursor position.
+.PP
+Functions prefixed with \*(``mv\*('' first perform cursor movement and
+fail if the position
+.RI ( y ,
+.IR x )
+is outside the window boundaries.
+.SH NOTES
+.BR add_wch ","
+.BR mvadd_wch ","
+.BR mvwadd_wch ","
+and
+.B echo_wchar
+may be implemented as macros.
+.SH EXTENSIONS
+.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 PORTABILITY
 .SH PORTABILITY

+These functions are described in X/Open Curses, Issue 4.
+It specifies no error conditions for them.

 .PP
 .PP

-All of these functions are described in the XSI Curses standard, Issue 4.
-The defaults specified for line-drawing characters apply in the POSIX locale.
+SVr4
+.I curses
+describes a successful return value only as
+\*(``an integer value other than
+.BR ERR \*(''.

 .PP
 .PP

+The defaults specified for forms-drawing characters apply in the POSIX
+locale.

 X/Open Curses makes it clear that the WACS_ symbols should be defined as
 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
 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
 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
 which are not in the SVr4 implementations.
 SVr4 curses implementations defined their line-drawing symbols in
 terms of intermediate symbols.
 This implementation extends those symbols, providing new definitions
 which are not in the SVr4 implementations.

+.PP
+Not all Unicode-capable terminals provide support for VT100-style
+alternate character sets (i.e., the \fBacsc\fP capability),
+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, 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.
+\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
+\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 \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:
+.bP
+The closest Unicode equivalents to the
+VT100 graphics \fIS1\fP, \fIS3\fP, \fIS7\fP and \fIS9\fP
+frequently are not displayed at
+the regular intervals which the terminal used.
+.bP
+The \fIlantern\fP is a special case.
+It originated with the AT&T 4410 terminal in the early 1980s.
+There is no accessible documentation depicting the lantern symbol
+on the AT&T terminal.
+.IP
+Lacking documentation, most readers assume that a \fIstorm lantern\fP
+was intended.
+But there are several possibilities, all with problems.
+.IP
+Unicode 6.0 (2010) does provide two lantern symbols: U+1F383 and U+1F3EE.
+Those were not available in 2002, and are irrelevant since
+they lie outside the BMP and as a result are not generally available
+in terminals.
+They are not storm lanterns, in any case.
+.IP
+Most \fIstorm lanterns\fP have a tapering glass chimney
+(to guard against tipping);
+some have a wire grid protecting the chimney.
+.IP
+For the tapering appearance, \[u2603] U+2603 was adequate.
+In use on a terminal, no one can tell what the image represents.
+Unicode calls it a snowman.
+.IP
+Others have suggested these alternatives:
+\[sc] U+00A7 (section mark),
+\[u0398] U+0398 (theta),
+\[u03A6] U+03A6 (phi),
+\[u03B4] U+03B4 (delta),
+\[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
+.I \%cchar_t
+can store more than one wide character
+.RI ( \%wchar_t ).
+X/Open Curses does not mention this possibility,
+specifying behavior only where
+.I wch
+is a single character,
+either spacing or non-spacing.
+.PP
+.I \%ncurses
+assumes that
+.I wch
+is constructed using \fB\%setcchar\fP(3X),
+and in turn that the result
+.bP
+contains at most one spacing character at the beginning of its list of
+wide characters,
+and zero or more non-spacing characters,
+or
+.bP
+holds one non-spacing character.
+.PP
+In the latter case,
+.I \%ncurses
+adds the non-spacing character to the active complex character.

 .SH SEE ALSO
 .SH SEE ALSO

+\fB\%curs_addch\fP(3X) describes comparable functions of the
+.I \%ncurses
+library in its non-wide-character configuration.

 .PP
 .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)