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43 <H1 class="no-header">curs_add_wch 3x 2024-03-23 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>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG>
117 <STRONG>ACS</STRONG> <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>Char</STRONG> <STRONG>Glyph</STRONG> <STRONG>Name</STRONG>
118 ------------------------------------------------------------------------
119 <STRONG>WACS_BLOCK</STRONG> 0x25ae # 0 solid square block
120 <STRONG>WACS_BOARD</STRONG> 0x2592 # h board of squares
121 <STRONG>WACS_BTEE</STRONG> 0x2534 + v bottom tee
122 <STRONG>WACS_BULLET</STRONG> 0x00b7 o ~ bullet
123 <STRONG>WACS_CKBOARD</STRONG> 0x2592 : a checker board (stipple)
124 <STRONG>WACS_DARROW</STRONG> 0x2193 v . arrow pointing down
125 <STRONG>WACS_DEGREE</STRONG> 0x00b0 ' f degree symbol
126 <STRONG>WACS_DIAMOND</STRONG> 0x25c6 + ` diamond
127 <STRONG>WACS_GEQUAL</STRONG> 0x2265 > > greater-than-or-equal-to
128 <STRONG>WACS_HLINE</STRONG> 0x2500 - q horizontal line
129 <STRONG>WACS_LANTERN</STRONG> 0x2603 # i lantern symbol
130 <STRONG>WACS_LARROW</STRONG> 0x2190 < , arrow pointing left
131 <STRONG>WACS_LEQUAL</STRONG> 0x2264 < y less-than-or-equal-to
132 <STRONG>WACS_LLCORNER</STRONG> 0x2514 + m lower left-hand corner
133 <STRONG>WACS_LRCORNER</STRONG> 0x2518 + j lower right-hand corner
134 <STRONG>WACS_LTEE</STRONG> 0x2524 + t left tee
135 <STRONG>WACS_NEQUAL</STRONG> 0x2260 ! | not-equal
136 <STRONG>WACS_PI</STRONG> 0x03c0 * { greek pi
137 <STRONG>WACS_PLMINUS</STRONG> 0x00b1 # g plus/minus
138 <STRONG>WACS_PLUS</STRONG> 0x253c + n plus
139 <STRONG>WACS_RARROW</STRONG> 0x2192 > + arrow pointing right
140 <STRONG>WACS_RTEE</STRONG> 0x251c + u right tee
141 <STRONG>WACS_S1</STRONG> 0x23ba - o scan line 1
142 <STRONG>WACS_S3</STRONG> 0x23bb - p scan line 3
143 <STRONG>WACS_S7</STRONG> 0x23bc - r scan line 7
144 <STRONG>WACS_S9</STRONG> 0x23bd _ s scan line 9
145 <STRONG>WACS_STERLING</STRONG> 0x00a3 f } pound-sterling symbol
146 <STRONG>WACS_TTEE</STRONG> 0x252c + w top tee
147 <STRONG>WACS_UARROW</STRONG> 0x2191 ^ - arrow pointing up
148 <STRONG>WACS_ULCORNER</STRONG> 0x250c + l upper left-hand corner
149 <STRONG>WACS_URCORNER</STRONG> 0x2510 + k upper right-hand corner
150 <STRONG>WACS_VLINE</STRONG> 0x2502 | x vertical line
152 The wide-character configuration of <EM>ncurses</EM> also defines symbols for
153 thick lines (<STRONG>acsc</STRONG> "J" to "V"):
155 <STRONG>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG>
156 <STRONG>ACS</STRONG> <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>Char</STRONG> <STRONG>Glyph</STRONG> <STRONG>Name</STRONG>
157 ------------------------------------------------------------------------
158 <STRONG>WACS_T_BTEE</STRONG> 0x253b + V thick tee pointing up
159 <STRONG>WACS_T_HLINE</STRONG> 0x2501 - Q thick horizontal line
160 <STRONG>WACS_T_LLCORNER</STRONG> 0x2517 + M thick lower left corner
161 <STRONG>WACS_T_LRCORNER</STRONG> 0x251b + J thick lower right corner
162 <STRONG>WACS_T_LTEE</STRONG> 0x252b + T thick tee pointing right
163 <STRONG>WACS_T_PLUS</STRONG> 0x254b + N thick large plus
164 <STRONG>WACS_T_RTEE</STRONG> 0x2523 + U thick tee pointing left
165 <STRONG>WACS_T_TTEE</STRONG> 0x2533 + W thick tee pointing down
166 <STRONG>WACS_T_ULCORNER</STRONG> 0x250f + L thick upper left corner
167 <STRONG>WACS_T_URCORNER</STRONG> 0x2513 + K thick upper right corner
168 <STRONG>WACS_T_VLINE</STRONG> 0x2503 | X thick vertical line
170 and for double-lines (<STRONG>acsc</STRONG> "A" to "I"):
172 <STRONG>Unicode</STRONG> <STRONG>ASCII</STRONG> <STRONG>acsc</STRONG>
173 <STRONG>ACS</STRONG> <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>Default</STRONG> <STRONG>Char</STRONG> <STRONG>Glyph</STRONG> <STRONG>Name</STRONG>
174 ------------------------------------------------------------------------
175 <STRONG>WACS_D_BTEE</STRONG> 0x2569 + H double tee pointing up
176 <STRONG>WACS_D_HLINE</STRONG> 0x2550 - R double horizontal line
177 <STRONG>WACS_D_LLCORNER</STRONG> 0x255a + D double lower left corner
178 <STRONG>WACS_D_LRCORNER</STRONG> 0x255d + A double lower right corner
179 <STRONG>WACS_D_LTEE</STRONG> 0x2560 + F double tee pointing right
180 <STRONG>WACS_D_PLUS</STRONG> 0x256c + E double large plus
181 <STRONG>WACS_D_RTEE</STRONG> 0x2563 + G double tee pointing left
183 <STRONG>WACS_D_TTEE</STRONG> 0x2566 + I double tee pointing down
184 <STRONG>WACS_D_ULCORNER</STRONG> 0x2554 + C double upper left corner
185 <STRONG>WACS_D_URCORNER</STRONG> 0x2557 + B double upper right corner
186 <STRONG>WACS_D_VLINE</STRONG> 0x2551 | Y double vertical line
188 Unicode's descriptions for these characters differs slightly from
189 <EM>ncurses</EM>, by introducing the term "light" (along with less important
190 details). Here are its descriptions for the normal, thick, and double
193 <STRONG>o</STRONG> U+2500 BOX DRAWINGS LIGHT HORIZONTAL
195 <STRONG>o</STRONG> U+2501 BOX DRAWINGS HEAVY HORIZONTAL
197 <STRONG>o</STRONG> U+2550 BOX DRAWINGS DOUBLE HORIZONTAL
200 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
201 All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on success.
203 X/Open Curses does not specify any error conditions. This
204 implementation returns an error
206 <STRONG>o</STRONG> if the window pointer is null or
208 <STRONG>o</STRONG> if it is not possible to add a complete character in the window.
210 The latter may be due to different causes:
212 <STRONG>o</STRONG> If <STRONG><A HREF="scrollok.3x.html">scrollok(3x)</A></STRONG> is not enabled, writing a character at the lower
213 right margin succeeds. However, an error is returned because it is
214 not possible to wrap to a new line.
216 <STRONG>o</STRONG> If an error is detected when converting a multibyte character to a
217 sequence of bytes, or if it is not possible to add all of the
218 resulting bytes in the window, an error is returned.
220 Functions with a "mv" prefix first perform a cursor movement using
221 <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
222 the window pointer is null.
225 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
226 Note that <STRONG>add_wch</STRONG>, <STRONG>mvadd_wch</STRONG>, <STRONG>mvwadd_wch</STRONG>, and <STRONG>echo_wchar</STRONG> may be macros.
229 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
230 These functions are described in the XSI Curses standard, Issue 4. The
231 defaults specified for line-drawing characters apply in the POSIX
235 </PRE><H3><a name="h3-WACS-Symbols">WACS Symbols</a></H3><PRE>
236 X/Open Curses makes it clear that the WACS_ symbols should be defined
237 as a pointer to <STRONG>cchar_t</STRONG> data, e.g., in the discussion of <STRONG>border_set</STRONG>. A
238 few implementations are problematic:
240 <STRONG>o</STRONG> NetBSD curses defines the symbols as a <STRONG>wchar_t</STRONG> within a <STRONG>cchar_t</STRONG>.
242 <STRONG>o</STRONG> HP-UX curses equates some of the <STRONG>ACS_</STRONG> symbols to the analogous
243 <STRONG>WACS_</STRONG> symbols as if the <STRONG>ACS_</STRONG> symbols were wide characters. The
244 misdefined symbols are the arrows and other symbols which are not
245 used for line-drawing.
247 X/Open Curses does not specify symbols for thick- or double-lines.
248 SVr4 curses implementations defined their line-drawing symbols in terms
249 of intermediate symbols. This implementation extends those symbols,
250 providing new definitions which are not in the SVr4 implementations.
252 Not all Unicode-capable terminals provide support for VT100-style
253 alternate character sets (i.e., the <STRONG>acsc</STRONG> capability), with their
254 corresponding line-drawing characters. X/Open Curses did not address
255 the aspect of integrating Unicode with line-drawing characters.
256 Existing implementations of Unix curses (AIX, HP-UX, Solaris) use only
257 the <STRONG>acsc</STRONG> character-mapping to provide this feature. As a result, those
258 implementations can only use single-byte line-drawing characters.
259 <EM>ncurses</EM> 5.3 (2002) provided a table of Unicode values to solve these
260 problems. NetBSD curses incorporated that table in 2010.
262 In this implementation, the Unicode values are used instead of the
263 terminal description's <STRONG>acsc</STRONG> mapping as discussed in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> for the
264 environment variable <EM>NCURSES</EM><STRONG>_</STRONG><EM>NO</EM><STRONG>_</STRONG><EM>UTF8</EM><STRONG>_</STRONG><EM>ACS</EM>. In contrast, for the same
265 cases, the line-drawing characters described in <STRONG><A HREF="curs_addch.3x.html">addch(3x)</A></STRONG> will use only
266 the ASCII default values.
268 Having Unicode available does not solve all of the problems with line-
271 <STRONG>o</STRONG> The closest Unicode equivalents to the VT100 graphics <EM>S1</EM>, <EM>S3</EM>, <EM>S7</EM>
272 and <EM>S9</EM> frequently are not displayed at the regular intervals which
275 <STRONG>o</STRONG> The <EM>lantern</EM> is a special case. It originated with the AT&T 4410
276 terminal in the early 1980s. There is no accessible documentation
277 depicting the lantern symbol on the AT&T terminal.
279 Lacking documentation, most readers assume that a <EM>storm</EM> <EM>lantern</EM> was
280 intended. But there are several possibilities, all with problems.
282 Unicode 6.0 (2010) does provide two lantern symbols: U+1F383 and
283 U+1F3EE. Those were not available in 2002, and are irrelevant
284 since they lie outside the BMP and as a result are not generally
285 available in terminals. They are not storm lanterns, in any case.
287 Most <EM>storm</EM> <EM>lanterns</EM> have a tapering glass chimney (to guard against
288 tipping); some have a wire grid protecting the chimney.
290 For the tapering appearance, U+2603 was adequate. In use on a
291 terminal, no one can tell what the image represents. Unicode calls
294 Others have suggested these alternatives: <section> U+00A7 (section
295 mark), <Theta> U+0398 (theta), <Phi> U+03A6 (phi), <delta> U+03B4
296 (delta), U+2327 (x in a rectangle), U+256C (forms double vertical
297 and horizontal), and U+2612 (ballot box with x).
300 </PRE><H3><a name="h3-Complex-Characters">Complex Characters</a></H3><PRE>
301 The complex character type <STRONG>cchar_t</STRONG> can store more than one wide
302 character (<STRONG>wchar_t</STRONG>). The X/Open Curses description does not mention
303 this possibility, describing only the cases where <EM>wch</EM> is a spacing
304 character or a non-spacing character.
306 This implementation assumes that <EM>wch</EM> is constructed using <STRONG><A HREF="curs_getcchar.3x.html">setcchar(3x)</A></STRONG>,
307 and in turn that the result
309 <STRONG>o</STRONG> contains at most one spacing character in the beginning of its list
310 of wide characters, and zero or more non-spacing characters or
312 <STRONG>o</STRONG> may hold one non-spacing character.
314 In the latter case, <EM>ncurses</EM> adds the non-spacing character to the
315 active (base) spacing character.
318 </PRE><H3><a name="h3-TABSIZE">TABSIZE</a></H3><PRE>
319 The <STRONG>TABSIZE</STRONG> variable is implemented in SVr4 and other versions of
320 <EM>curses</EM>, but is not specified by X/Open Curses (see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>).
323 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
324 <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_addwstr.3x.html">curs_addwstr(3x)</A></STRONG>, <STRONG><A HREF="curs_add_wchstr.3x.html">curs_add_wchstr(3x)</A></STRONG>,
325 <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>, <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>,
326 <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>putwc(3)</STRONG>
330 ncurses 6.4 2024-03-23 <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>
334 <li><a href="#h2-NAME">NAME</a></li>
335 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
336 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
338 <li><a href="#h3-add_wch">add_wch</a></li>
339 <li><a href="#h3-echo_wchar">echo_wchar</a></li>
340 <li><a href="#h3-Line-Graphics">Line Graphics</a></li>
343 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
344 <li><a href="#h2-NOTES">NOTES</a></li>
345 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
347 <li><a href="#h3-WACS-Symbols">WACS Symbols</a></li>
348 <li><a href="#h3-Complex-Characters">Complex Characters</a></li>
349 <li><a href="#h3-TABSIZE">TABSIZE</a></li>
352 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>