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43 <H1 class="no-header">curs_add_wch 3x 2023-10-07 ncurses 6.4 Library calls</H1>
45 <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51 <STRONG>add_wch</STRONG>, <STRONG>wadd_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, <STRONG>mvwadd_wch</STRONG>, <STRONG>echo_wchar</STRONG>, <STRONG>wecho_wchar</STRONG> - add
52 a <EM>curses</EM> complex character to a window and advance the cursor
55 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
56 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
58 <STRONG>int</STRONG> <STRONG>add_wch(const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
59 <STRONG>int</STRONG> <STRONG>wadd_wch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
60 <STRONG>int</STRONG> <STRONG>mvadd_wch(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
61 <STRONG>int</STRONG> <STRONG>mvwadd_wch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
63 <STRONG>int</STRONG> <STRONG>echo_wchar(const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
64 <STRONG>int</STRONG> <STRONG>wecho_wchar(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>);</STRONG>
67 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
69 </PRE><H3><a name="h3-add_wch">add_wch</a></H3><PRE>
70 The <STRONG>add_wch</STRONG>, <STRONG>wadd_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, and <STRONG>mvwadd_wch</STRONG> functions put the
71 complex character <EM>wch</EM> into the given window at its current position,
72 which is then advanced. These functions perform wrapping and special-
73 character processing as follows:
75 <STRONG>o</STRONG> If <EM>wch</EM> refers to a spacing character, then any previous character
76 at that location is removed. A new character specified by <EM>wch</EM> is
77 placed at that location with rendition specified by <EM>wch</EM>. The
78 cursor then advances after this spacing character, to prepare for
79 writing the next character on the screen.
81 The newly added spacing character is the base of the active complex
82 character. Subsequent non-spacing characters can be combined with
83 this base until another spacing character is written to the screen,
84 or the cursor is moved, e.g., using <STRONG>wmove</STRONG>.
86 <STRONG>o</STRONG> If <EM>wch</EM> refers to a non-spacing character, it is appended to the
87 active complex character, retaining the previous characters at that
88 location. The rendition specified by <EM>wch</EM> is ignored.
90 The cursor is not advanced after adding a non-spacing character.
91 Subsequent calls to add non-spacing characters will update the same
94 <STRONG>o</STRONG> If the character part of <EM>wch</EM> is a tab, newline, backspace or other
95 control character, the window is updated and the cursor moves as if
96 <STRONG>addch</STRONG> were called.
99 </PRE><H3><a name="h3-echo_wchar">echo_wchar</a></H3><PRE>
100 The <STRONG>echo_wchar</STRONG> function is functionally equivalent to a call to <STRONG>add_wch</STRONG>
101 followed by a call to <STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG>. Similarly, the <STRONG>wecho_wchar</STRONG> is
102 functionally equivalent to a call to <STRONG>wadd_wch</STRONG> followed by a call to
103 <STRONG>wrefresh</STRONG>. The knowledge that only a single character is being output
104 is taken into consideration and, for non-control characters, a
105 considerable performance gain might be seen by using the *<STRONG>echo</STRONG>*
106 functions instead of their equivalents.
109 </PRE><H3><a name="h3-Line-Graphics">Line Graphics</a></H3><PRE>
110 Like <STRONG><A HREF="curs_addch.3x.html">addch(3x)</A></STRONG>, <STRONG>addch_wch</STRONG> accepts symbols which make it simple to draw
111 lines and other frequently used special characters. These symbols
112 correspond to the same VT100 line-drawing set as <STRONG><A HREF="curs_addch.3x.html">addch(3x)</A></STRONG>.
114 <STRONG>ACS</STRONG> <STRONG>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG> <STRONG>Glyph</STRONG>
115 <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>char</STRONG> <STRONG>Name</STRONG>
117 ------------------------------------------------------------------------
118 WACS_BLOCK 0x25ae # 0 solid square block
119 WACS_BOARD 0x2592 # h board of squares
120 WACS_BTEE 0x2534 + v bottom tee
121 WACS_BULLET 0x00b7 o ~ bullet
122 WACS_CKBOARD 0x2592 : a checker board (stipple)
123 WACS_DARROW 0x2193 v . arrow pointing down
124 WACS_DEGREE 0x00b0 ' f degree symbol
125 WACS_DIAMOND 0x25c6 + ` diamond
126 WACS_GEQUAL 0x2265 > > greater-than-or-equal-to
127 WACS_HLINE 0x2500 - q horizontal line
128 WACS_LANTERN 0x2603 # i lantern symbol
129 WACS_LARROW 0x2190 < , arrow pointing left
130 WACS_LEQUAL 0x2264 < y less-than-or-equal-to
131 WACS_LLCORNER 0x2514 + m lower left-hand corner
132 WACS_LRCORNER 0x2518 + j lower right-hand corner
133 WACS_LTEE 0x2524 + t left tee
134 WACS_NEQUAL 0x2260 ! | not-equal
135 WACS_PI 0x03c0 * { greek pi
136 WACS_PLMINUS 0x00b1 # g plus/minus
137 WACS_PLUS 0x253c + n plus
138 WACS_RARROW 0x2192 > + arrow pointing right
139 WACS_RTEE 0x251c + u right tee
140 WACS_S1 0x23ba - o scan line 1
141 WACS_S3 0x23bb - p scan line 3
142 WACS_S7 0x23bc - r scan line 7
143 WACS_S9 0x23bd _ s scan line 9
144 WACS_STERLING 0x00a3 f } pound-sterling symbol
145 WACS_TTEE 0x252c + w top tee
146 WACS_UARROW 0x2191 ^ - arrow pointing up
147 WACS_ULCORNER 0x250c + l upper left-hand corner
148 WACS_URCORNER 0x2510 + k upper right-hand corner
149 WACS_VLINE 0x2502 | x vertical line
151 The wide-character configuration of ncurses also defines symbols for
152 thick lines (<STRONG>acsc</STRONG> "J" to "V"):
154 <STRONG>ACS</STRONG> <STRONG>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG> <STRONG>Glyph</STRONG>
155 <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>char</STRONG> <STRONG>Name</STRONG>
156 -----------------------------------------------------------------------
157 WACS_T_BTEE 0x253b + V thick tee pointing up
158 WACS_T_HLINE 0x2501 - Q thick horizontal line
159 WACS_T_LLCORNER 0x2517 + M thick lower left corner
160 WACS_T_LRCORNER 0x251b + J thick lower right corner
161 WACS_T_LTEE 0x252b + T thick tee pointing right
162 WACS_T_PLUS 0x254b + N thick large plus
163 WACS_T_RTEE 0x2523 + U thick tee pointing left
164 WACS_T_TTEE 0x2533 + W thick tee pointing down
165 WACS_T_ULCORNER 0x250f + L thick upper left corner
166 WACS_T_URCORNER 0x2513 + K thick upper right corner
167 WACS_T_VLINE 0x2503 | X thick vertical line
169 and for double-lines (<STRONG>acsc</STRONG> "A" to "I"):
171 <STRONG>ACS</STRONG> <STRONG>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG> <STRONG>Glyph</STRONG>
172 <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>char</STRONG> <STRONG>Name</STRONG>
173 ------------------------------------------------------------------------
174 WACS_D_BTEE 0x2569 + H double tee pointing up
175 WACS_D_HLINE 0x2550 - R double horizontal line
176 WACS_D_LLCORNER 0x255a + D double lower left corner
177 WACS_D_LRCORNER 0x255d + A double lower right corner
178 WACS_D_LTEE 0x2560 + F double tee pointing right
179 WACS_D_PLUS 0x256c + E double large plus
180 WACS_D_RTEE 0x2563 + G double tee pointing left
181 WACS_D_TTEE 0x2566 + I double tee pointing down
183 WACS_D_ULCORNER 0x2554 + C double upper left corner
184 WACS_D_URCORNER 0x2557 + B double upper right corner
185 WACS_D_VLINE 0x2551 | Y double vertical line
187 Unicode's descriptions for these characters differs slightly from
188 ncurses, by introducing the term "light" (along with less important
189 details). Here are its descriptions for the normal, thick, and double
192 <STRONG>o</STRONG> U+2500 BOX DRAWINGS LIGHT HORIZONTAL
194 <STRONG>o</STRONG> U+2501 BOX DRAWINGS HEAVY HORIZONTAL
196 <STRONG>o</STRONG> U+2550 BOX DRAWINGS DOUBLE HORIZONTAL
199 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
200 All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on success.
202 X/Open does not define any error conditions. This implementation
205 <STRONG>o</STRONG> if the window pointer is null or
207 <STRONG>o</STRONG> if it is not possible to add a complete character in the window.
209 The latter may be due to different causes:
211 <STRONG>o</STRONG> If <STRONG><A HREF="scrollok.3x.html">scrollok(3x)</A></STRONG> is not enabled, writing a character at the lower
212 right margin succeeds. However, an error is returned because it is
213 not possible to wrap to a new line
215 <STRONG>o</STRONG> If an error is detected when converting a multibyte character to a
216 sequence of bytes, or if it is not possible to add all of the
217 resulting bytes in the window, an error is returned.
219 Functions with a "mv" prefix first perform a cursor movement using
220 <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
221 the window pointer is null.
224 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
225 Note that <STRONG>add_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, <STRONG>mvwadd_wch</STRONG>, and <STRONG>echo_wchar</STRONG> may be macros.
228 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
229 All of these functions are described in the XSI Curses standard, Issue
230 4. The defaults specified for line-drawing characters apply in the
234 </PRE><H3><a name="h3-WACS-Symbols">WACS Symbols</a></H3><PRE>
235 X/Open Curses makes it clear that the WACS_ symbols should be defined
236 as a pointer to <STRONG>cchar_t</STRONG> data, e.g., in the discussion of <STRONG>border_set</STRONG>. A
237 few implementations are problematic:
239 <STRONG>o</STRONG> NetBSD curses defines the symbols as a <STRONG>wchar_t</STRONG> within a <STRONG>cchar_t</STRONG>.
241 <STRONG>o</STRONG> HPUX curses equates some of the <STRONG>ACS_</STRONG> symbols to the analogous <STRONG>WACS_</STRONG>
242 symbols as if the <STRONG>ACS_</STRONG> symbols were wide characters. The
243 misdefined symbols are the arrows and other symbols which are not
244 used for line-drawing.
246 X/Open Curses does not define symbols for thick- or double-lines. SVr4
247 curses implementations defined their line-drawing symbols in terms of
248 intermediate symbols. This implementation extends those symbols,
249 providing new definitions which are not in the SVr4 implementations.
251 Not all Unicode-capable terminals provide support for VT100-style
252 alternate character sets (i.e., the <STRONG>acsc</STRONG> capability), with their
253 corresponding line-drawing characters. X/Open Curses did not address
254 the aspect of integrating Unicode with line-drawing characters.
255 Existing implementations of Unix curses (AIX, HPUX, Solaris) use only
256 the <STRONG>acsc</STRONG> character-mapping to provide this feature. As a result, those
257 implementations can only use single-byte line-drawing characters.
258 Ncurses 5.3 (2002) provided a table of Unicode values to solve these
259 problems. NetBSD curses incorporated that table in 2010.
261 In this implementation, the Unicode values are used instead of the
262 terminal description's <STRONG>acsc</STRONG> mapping as discussed in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> for the
263 environment variable <STRONG>NCURSES_NO_UTF8_ACS</STRONG>. In contrast, for the same
264 cases, the line-drawing characters described in <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG> will use
265 only the ASCII default values.
267 Having Unicode available does not solve all of the problems with line-
270 <STRONG>o</STRONG> The closest Unicode equivalents to the VT100 graphics <EM>S1</EM>, <EM>S3</EM>, <EM>S7</EM>
271 and <EM>S9</EM> frequently are not displayed at the regular intervals which
274 <STRONG>o</STRONG> The <EM>lantern</EM> is a special case. It originated with the AT&T 4410
275 terminal in the early 1980s. There is no accessible documentation
276 depicting the lantern symbol on the AT&T terminal.
278 Lacking documentation, most readers assume that a <EM>storm</EM> <EM>lantern</EM> was
279 intended. But there are several possibilities, all with problems.
281 Unicode 6.0 (2010) does provide two lantern symbols: U+1F383 and
282 U+1F3EE. Those were not available in 2002, and are irrelevant
283 since they lie outside the BMP and as a result are not generally
284 available in terminals. They are not storm lanterns, in any case.
286 Most <EM>storm</EM> <EM>lanterns</EM> have a tapering glass chimney (to guard against
287 tipping); some have a wire grid protecting the chimney.
289 For the tapering appearance, U+2603 was adequate. In use on a
290 terminal, no one can tell what the image represents. Unicode calls
293 Others have suggested these alternatives: <section> U+00A7 (section
294 mark), <Theta> U+0398 (theta), <Phi> U+03A6 (phi), <delta> U+03B4
295 (delta), U+2327 (x in a rectangle), U+256C (forms double vertical
296 and horizontal), and U+2612 (ballot box with x).
299 </PRE><H3><a name="h3-Complex-Characters">Complex Characters</a></H3><PRE>
300 The complex character type <STRONG>cchar_t</STRONG> can store more than one wide
301 character (<STRONG>wchar_t</STRONG>). The X/Open Curses description does not mention
302 this possibility, describing only the cases where <EM>wch</EM> is a spacing
303 character or a non-spacing character.
305 This implementation assumes that <EM>wch</EM> is constructed using <STRONG><A HREF="curs_getcchar.3x.html">setcchar(3x)</A></STRONG>,
306 and in turn that the result
308 <STRONG>o</STRONG> contains at most one spacing character in the beginning of its list
309 of wide characters, and zero or more non-spacing characters or
311 <STRONG>o</STRONG> may hold one non-spacing character.
313 In the latter case, ncurses adds the non-spacing character to the
314 active (base) spacing character.
317 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
318 <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>,
319 <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG>putwc(3)</STRONG>
323 ncurses 6.4 2023-10-07 <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
327 <li><a href="#h2-NAME">NAME</a></li>
328 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
329 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
331 <li><a href="#h3-add_wch">add_wch</a></li>
332 <li><a href="#h3-echo_wchar">echo_wchar</a></li>
333 <li><a href="#h3-Line-Graphics">Line Graphics</a></li>
336 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
337 <li><a href="#h2-NOTES">NOTES</a></li>
338 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
340 <li><a href="#h3-WACS-Symbols">WACS Symbols</a></li>
341 <li><a href="#h3-Complex-Characters">Complex Characters</a></li>
344 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>