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31 * @Id: curs_addch.3x,v 1.54 2020/10/17 23:02:40 tom Exp @
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43 <H1 class="no-header">curs_addch 3x</H1>
45 <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG> <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
50 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
51 <STRONG>addch</STRONG>, <STRONG>waddch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, <STRONG>echochar</STRONG>, <STRONG>wechochar</STRONG> - add a character
52 (with attributes) to a <STRONG>curses</STRONG> window, then 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>addch(const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
59 <STRONG>int</STRONG> <STRONG>waddch(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
60 <STRONG>int</STRONG> <STRONG>mvaddch(int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
61 <STRONG>int</STRONG> <STRONG>mvwaddch(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
63 <STRONG>int</STRONG> <STRONG>echochar(const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
64 <STRONG>int</STRONG> <STRONG>wechochar(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
67 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
69 </PRE><H3><a name="h3-Adding-characters">Adding characters</a></H3><PRE>
70 The <STRONG>addch</STRONG>, <STRONG>waddch</STRONG>, <STRONG>mvaddch</STRONG> and <STRONG>mvwaddch</STRONG> routines put the character <EM>ch</EM>
71 into the given window at its current window position, which is then
72 advanced. They are analogous to <STRONG>putchar(3)</STRONG> in <STRONG>stdio(3)</STRONG>. If the
73 advance is at the right margin:
75 <STRONG>o</STRONG> The cursor automatically wraps to the beginning of the next line.
77 <STRONG>o</STRONG> At the bottom of the current scrolling region, and if <STRONG>scrollok</STRONG> is
78 enabled, the scrolling region is scrolled up one line.
80 <STRONG>o</STRONG> If <STRONG>scrollok</STRONG> is not enabled, writing a character at the lower right
81 margin succeeds. However, an error is returned because it is not
82 possible to wrap to a new line
84 If <EM>ch</EM> is a tab, newline, carriage return or backspace, the cursor is
85 moved appropriately within the window:
87 <STRONG>o</STRONG> Backspace moves the cursor one character left; at the left edge of
88 a window it does nothing.
90 <STRONG>o</STRONG> Carriage return moves the cursor to the window left margin on the
93 <STRONG>o</STRONG> Newline does a <STRONG>clrtoeol</STRONG>, then moves the cursor to the window left
94 margin on the next line, scrolling the window if on the last line.
96 <STRONG>o</STRONG> Tabs are considered to be at every eighth column. The tab interval
97 may be altered by setting the <STRONG>TABSIZE</STRONG> variable.
99 If <EM>ch</EM> is any other nonprintable character, it is drawn in printable
100 form, i.e., the <STRONG>^</STRONG><EM>X</EM> notation used by <STRONG><A HREF="unctrl.3x.html">unctrl(3x)</A></STRONG>. Calling <STRONG>winch</STRONG> after
101 adding a nonprintable character does not return the character itself,
102 but instead returns the printable representation of the character.
104 Video attributes can be combined with a character argument passed to
105 <STRONG>addch</STRONG> or related functions by logical-ORing them into the character.
106 (Thus, text, including attributes, can be copied from one place to
107 another using <STRONG><A HREF="curs_inch.3x.html">inch(3x)</A></STRONG> and <STRONG>addch</STRONG>.) See the <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG> page for val-
108 ues of predefined video attribute constants that can be usefully OR'ed
112 </PRE><H3><a name="h3-Echoing-characters">Echoing characters</a></H3><PRE>
113 The <STRONG>echochar</STRONG> and <STRONG>wechochar</STRONG> routines are equivalent to a call to <STRONG>addch</STRONG>
114 followed by a call to <STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG>, or a call to <STRONG>waddch</STRONG> followed by a
115 call to <STRONG>wrefresh</STRONG>. The knowledge that only a single character is being
116 output is used and, for non-control characters, a considerable perfor-
117 mance gain may be seen by using these routines instead of their equiva-
121 </PRE><H3><a name="h3-Line-Graphics">Line Graphics</a></H3><PRE>
122 The following variables may be used to add line drawing characters to
123 the screen with routines of the <STRONG>addch</STRONG> family. The default character
124 listed below is used if the <STRONG>acsc</STRONG> capability does not define a terminal-
125 specific replacement for it, or if the terminal and locale configura-
126 tion requires Unicode but the library is unable to use Unicode.
128 The names are taken from VT100 nomenclature.
130 <STRONG>ACS</STRONG> <STRONG>ACS</STRONG> <STRONG>acsc</STRONG> <STRONG>Glyph</STRONG>
131 <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>char</STRONG> <STRONG>Name</STRONG>
132 ---------------------------------------------------------
133 ACS_BLOCK # 0 solid square block
134 ACS_BOARD # h board of squares
135 ACS_BTEE + v bottom tee
136 ACS_BULLET o ~ bullet
137 ACS_CKBOARD : a checker board (stipple)
138 ACS_DARROW v . arrow pointing down
139 ACS_DEGREE ' f degree symbol
140 ACS_DIAMOND + ` diamond
141 ACS_GEQUAL > > greater-than-or-equal-to
142 ACS_HLINE - q horizontal line
143 ACS_LANTERN # i lantern symbol
144 ACS_LARROW < , arrow pointing left
145 ACS_LEQUAL < y less-than-or-equal-to
146 ACS_LLCORNER + m lower left-hand corner
147 ACS_LRCORNER + j lower right-hand corner
148 ACS_LTEE + t left tee
149 ACS_NEQUAL ! | not-equal
151 ACS_PLMINUS # g plus/minus
153 ACS_RARROW > + arrow pointing right
154 ACS_RTEE + u right tee
155 ACS_S1 - o scan line 1
156 ACS_S3 - p scan line 3
157 ACS_S7 - r scan line 7
158 ACS_S9 _ s scan line 9
159 ACS_STERLING f } pound-sterling symbol
161 ACS_UARROW ^ - arrow pointing up
162 ACS_ULCORNER + l upper left-hand corner
163 ACS_URCORNER + k upper right-hand corner
164 ACS_VLINE | x vertical line
167 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
168 All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on success (the
169 SVr4 manuals specify only "an integer value other than <STRONG>ERR</STRONG>") upon suc-
170 cessful completion, unless otherwise noted in the preceding routine
173 Functions with a "mv" prefix first perform a cursor movement using
174 <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
175 the window pointer is null.
177 If it is not possible to add a complete character, an error is
180 <STRONG>o</STRONG> If <STRONG>scrollok</STRONG> is not enabled, writing a character at the lower right
181 margin succeeds. However, an error is returned because it is not
182 possible to wrap to a new line
184 <STRONG>o</STRONG> If an error is detected when converting a multibyte character to a
185 sequence of bytes, or if it is not possible to add all of the
186 resulting bytes in the window, an error is returned.
189 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
190 Note that <STRONG>addch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, and <STRONG>echochar</STRONG> may be macros.
193 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
194 All these functions are described in the XSI Curses standard, Issue 4.
195 The defaults specified for forms-drawing characters apply in the POSIX
199 </PRE><H3><a name="h3-ACS-Symbols">ACS Symbols</a></H3><PRE>
200 X/Open Curses states that the <EM>ACS</EM><STRONG>_</STRONG> definitions are <STRONG>char</STRONG> constants. For
201 the wide-character implementation (see <STRONG>curs_add_wch</STRONG>), there are analo-
202 gous <EM>WACS</EM><STRONG>_</STRONG> definitions which are <STRONG>cchar_t</STRONG> constants. Some implementa-
203 tions are problematic:
205 <STRONG>o</STRONG> Some implementations define the ACS symbols to a constant (such as
206 Solaris), while others define those to entries in an array.
208 This implementation uses an array <STRONG>acs_map</STRONG>, as done in SVr4 curses.
209 NetBSD also uses an array, actually named <STRONG>_acs_char</STRONG>, with a <STRONG>#define</STRONG>
212 <STRONG>o</STRONG> HPUX curses equates some of the <EM>ACS</EM><STRONG>_</STRONG> symbols to the analogous <EM>WACS</EM><STRONG>_</STRONG>
213 symbols as if the <EM>ACS</EM><STRONG>_</STRONG> symbols were wide characters. The misde-
214 fined symbols are the arrows and other symbols which are not used
217 <STRONG>o</STRONG> X/Open Curses (issues 2 through 7) has a typographical error for
218 the ACS_LANTERN symbol, equating its "VT100+ Character" to <STRONG>I</STRONG> (capi-
219 tal I), while the header files for SVr4 curses and the various
220 implementations use <STRONG>i</STRONG> (lowercase).
222 None of the terminal descriptions on Unix platforms use uppercase-
223 I, except for Solaris (i.e., <EM>screen</EM>'s terminal description, appar-
224 ently based on the X/Open documentation around 1995). On the other
225 hand, the terminal description <EM>gs6300</EM> (AT&T PC6300 with EMOTS Ter-
226 minal Emulator) uses lowercase-i.
228 Some ACS symbols (ACS_S3, ACS_S7, ACS_LEQUAL, ACS_GEQUAL, ACS_PI,
229 ACS_NEQUAL, ACS_STERLING) were not documented in any publicly released
230 System V. However, many publicly available terminfos include <STRONG>acsc</STRONG>
231 strings in which their key characters (pryz{|}) are embedded, and a
232 second-hand list of their character descriptions has come to light.
233 The ACS-prefixed names for them were invented for <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>.
235 The <EM>displayed</EM> values for the <EM>ACS</EM><STRONG>_</STRONG> and <EM>WACS</EM><STRONG>_</STRONG> constants depend on
237 <STRONG>o</STRONG> the library configuration, i.e., <STRONG>ncurses</STRONG> versus <STRONG>ncursesw</STRONG>, where the
238 latter is capable of displaying Unicode while the former is not,
241 <STRONG>o</STRONG> whether the <EM>locale</EM> uses UTF-8 encoding.
243 In certain cases, the terminal is unable to display line-drawing char-
244 acters except by using UTF-8 (see the discussion of <STRONG>NCURSES_NO_UTF8_ACS</STRONG>
245 in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>).
248 </PRE><H3><a name="h3-Character-Set">Character Set</a></H3><PRE>
249 X/Open Curses assumes that the parameter passed to <STRONG>waddch</STRONG> contains a
250 single character. As discussed in <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, that character may
251 have been more than eight bits in an SVr3 or SVr4 implementation, but
252 in the X/Open Curses model, the details are not given. The important
253 distinction between SVr4 curses and X/Open Curses is that the non-char-
254 acter information (attributes and color) was separated from the charac-
255 ter information which is packed in a <STRONG>chtype</STRONG> to pass to <STRONG>waddch</STRONG>.
257 In this implementation, <STRONG>chtype</STRONG> holds an eight-bit character. But
258 ncurses allows multibyte characters to be passed in a succession of
259 calls to <STRONG>waddch</STRONG>. The other implementations do not do this; a call to
260 <STRONG>waddch</STRONG> passes exactly one character which may be rendered as one or
261 more cells on the screen depending on whether it is printable.
263 Depending on the locale settings, ncurses will inspect the byte passed
264 in each call to <STRONG>waddch</STRONG>, and check if the latest call will continue a
265 multibyte sequence. When a character is <EM>complete</EM>, ncurses displays the
266 character and moves to the next position in the screen.
268 If the calling application interrupts the succession of bytes in a
269 multibyte character by moving the current location (e.g., using <STRONG>wmove</STRONG>),
270 ncurses discards the partially built character, starting over again.
272 For portability to other implementations, do not rely upon this behav-
275 <STRONG>o</STRONG> check if a character can be represented as a single byte in the
276 current locale before attempting call <STRONG>waddch</STRONG>, and
278 <STRONG>o</STRONG> call <STRONG>wadd_wch</STRONG> for characters which cannot be handled by <STRONG>waddch</STRONG>.
281 </PRE><H3><a name="h3-TABSIZE">TABSIZE</a></H3><PRE>
282 The <STRONG>TABSIZE</STRONG> variable is implemented in SVr4 and other versions of
283 curses, but is not part of X/Open curses (see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG> for
286 If <EM>ch</EM> is a carriage return, the cursor is moved to the beginning of the
287 current row of the window. This is true of other implementations, but
291 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
292 <STRONG><A HREF="ncurses.3x.html">curses(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>, <STRONG><A HREF="curs_inch.3x.html">curs_inch(3x)</A></STRONG>, <STRONG>curs_out-</STRONG>
293 <STRONG><A HREF="curs_outopts.3x.html">opts(3x)</A></STRONG>, <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>putc(3)</STRONG>.
295 Comparable functions in the wide-character (ncursesw) library are
296 described in <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>.
300 <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
304 <li><a href="#h2-NAME">NAME</a></li>
305 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
306 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
308 <li><a href="#h3-Adding-characters">Adding characters</a></li>
309 <li><a href="#h3-Echoing-characters">Echoing characters</a></li>
310 <li><a href="#h3-Line-Graphics">Line Graphics</a></li>
313 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
314 <li><a href="#h2-NOTES">NOTES</a></li>
315 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
317 <li><a href="#h3-ACS-Symbols">ACS Symbols</a></li>
318 <li><a href="#h3-Character-Set">Character Set</a></li>
319 <li><a href="#h3-TABSIZE">TABSIZE</a></li>
322 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>