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31 * @Id: curs_addch.3x,v 1.59 2022/02/12 20:07:29 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> <EM>ch</EM><STRONG>);</STRONG>
59 <STRONG>int</STRONG> <STRONG>waddch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
60 <STRONG>int</STRONG> <STRONG>mvaddch(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
61 <STRONG>int</STRONG> <STRONG>mvwaddch(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>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
63 <STRONG>int</STRONG> <STRONG>echochar(const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
64 <STRONG>int</STRONG> <STRONG>wechochar(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</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
108 values of predefined video attribute constants that can be usefully
109 OR'ed into characters.
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
117 performance gain may be seen by using these routines instead of their
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
126 configuration requires Unicode but the library is unable to use
129 The names are taken from VT100 nomenclature.
131 <STRONG>ACS</STRONG> <STRONG>ACS</STRONG> <STRONG>acsc</STRONG> <STRONG>Glyph</STRONG>
132 <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>char</STRONG> <STRONG>Name</STRONG>
133 ---------------------------------------------------------
134 ACS_BLOCK # 0 solid square block
135 ACS_BOARD # h board of squares
136 ACS_BTEE + v bottom tee
137 ACS_BULLET o ~ bullet
138 ACS_CKBOARD : a checker board (stipple)
139 ACS_DARROW v . arrow pointing down
140 ACS_DEGREE ' f degree symbol
141 ACS_DIAMOND + ` diamond
142 ACS_GEQUAL > > greater-than-or-equal-to
143 ACS_HLINE - q horizontal line
144 ACS_LANTERN # i lantern symbol
145 ACS_LARROW < , arrow pointing left
146 ACS_LEQUAL < y less-than-or-equal-to
147 ACS_LLCORNER + m lower left-hand corner
148 ACS_LRCORNER + j lower right-hand corner
149 ACS_LTEE + t left tee
150 ACS_NEQUAL ! | not-equal
152 ACS_PLMINUS # g plus/minus
154 ACS_RARROW > + arrow pointing right
155 ACS_RTEE + u right tee
156 ACS_S1 - o scan line 1
157 ACS_S3 - p scan line 3
158 ACS_S7 - r scan line 7
159 ACS_S9 _ s scan line 9
160 ACS_STERLING f } pound-sterling symbol
162 ACS_UARROW ^ - arrow pointing up
163 ACS_ULCORNER + l upper left-hand corner
164 ACS_URCORNER + k upper right-hand corner
165 ACS_VLINE | x vertical line
168 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
169 All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on success (the
170 SVr4 manuals specify only "an integer value other than <STRONG>ERR</STRONG>") upon
171 successful completion, unless otherwise noted in the preceding routine
174 Functions with a "mv" prefix first perform a cursor movement using
175 <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
176 the window pointer is null.
178 If it is not possible to add a complete character, an error is
181 <STRONG>o</STRONG> If <STRONG>scrollok</STRONG> is not enabled, writing a character at the lower right
182 margin succeeds. However, an error is returned because it is not
183 possible to wrap to a new line
185 <STRONG>o</STRONG> If an error is detected when converting a multibyte character to a
186 sequence of bytes, or if it is not possible to add all of the
187 resulting bytes in the window, an error is returned.
190 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
191 Note that <STRONG>addch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, and <STRONG>echochar</STRONG> may be macros.
194 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
195 All these functions are described in the XSI Curses standard, Issue 4.
196 The defaults specified for forms-drawing characters apply in the POSIX
200 </PRE><H3><a name="h3-ACS-Symbols">ACS Symbols</a></H3><PRE>
201 X/Open Curses states that the <STRONG>ACS_</STRONG> definitions are <STRONG>char</STRONG> constants. For
202 the wide-character implementation (see <STRONG>curs_add_wch</STRONG>), there are
203 analogous <STRONG>WACS_</STRONG> definitions which are <STRONG>cchar_t</STRONG> constants. Some
204 implementations are problematic:
206 <STRONG>o</STRONG> Some implementations define the ACS symbols to a constant (such as
207 Solaris), while others define those to entries in an array.
209 This implementation uses an array <STRONG>acs_map</STRONG>, as done in SVr4 curses.
210 NetBSD also uses an array, actually named <STRONG>_acs_char</STRONG>, with a <STRONG>#define</STRONG>
213 <STRONG>o</STRONG> HPUX curses equates some of the <STRONG>ACS_</STRONG> symbols to the analogous <STRONG>WACS_</STRONG>
214 symbols as if the <STRONG>ACS_</STRONG> symbols were wide characters. The
215 misdefined symbols are the arrows and other symbols which are not
216 used for line-drawing.
218 <STRONG>o</STRONG> X/Open Curses (issues 2 through 7) has a typographical error for
219 the ACS_LANTERN symbol, equating its "VT100+ Character" to <STRONG>I</STRONG>
220 (capital I), while the header files for SVr4 curses and the various
221 implementations use <STRONG>i</STRONG> (lowercase).
223 None of the terminal descriptions on Unix platforms use uppercase-
224 I, except for Solaris (i.e., <STRONG>screen</STRONG>'s terminal description,
225 apparently based on the X/Open documentation around 1995). On the
226 other hand, the terminal description <EM>gs6300</EM> (AT&T PC6300 with EMOTS
227 Terminal Emulator) uses lowercase-i.
229 Some ACS symbols (ACS_S3, ACS_S7, ACS_LEQUAL, ACS_GEQUAL, ACS_PI,
230 ACS_NEQUAL, ACS_STERLING) were not documented in any publicly released
231 System V. However, many publicly available terminfos include <STRONG>acsc</STRONG>
232 strings in which their key characters (pryz{|}) are embedded, and a
233 second-hand list of their character descriptions has come to light.
234 The ACS-prefixed names for them were invented for <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>.
236 The <EM>displayed</EM> values for the <STRONG>ACS_</STRONG> and <STRONG>WACS_</STRONG> constants depend on
238 <STRONG>o</STRONG> the library configuration, i.e., <STRONG>ncurses</STRONG> versus <STRONG>ncursesw</STRONG>, where the
239 latter is capable of displaying Unicode while the former is not,
242 <STRONG>o</STRONG> whether the <EM>locale</EM> uses UTF-8 encoding.
244 In certain cases, the terminal is unable to display line-drawing
245 characters except by using UTF-8 (see the discussion of
246 <STRONG>NCURSES_NO_UTF8_ACS</STRONG> in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>).
249 </PRE><H3><a name="h3-Character-Set">Character Set</a></H3><PRE>
250 X/Open Curses assumes that the parameter passed to <STRONG>waddch</STRONG> contains a
251 single character. As discussed in <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, that character may
252 have been more than eight bits in an SVr3 or SVr4 implementation, but
253 in the X/Open Curses model, the details are not given. The important
254 distinction between SVr4 curses and X/Open Curses is that the non-
255 character information (attributes and color) was separated from the
256 character information which is packed in a <STRONG>chtype</STRONG> to pass to <STRONG>waddch</STRONG>.
258 In this implementation, <STRONG>chtype</STRONG> holds an eight-bit character. But
259 ncurses allows multibyte characters to be passed in a succession of
260 calls to <STRONG>waddch</STRONG>. The other implementations do not do this; a call to
261 <STRONG>waddch</STRONG> passes exactly one character which may be rendered as one or
262 more cells on the screen depending on whether it is printable.
264 Depending on the locale settings, ncurses will inspect the byte passed
265 in each call to <STRONG>waddch</STRONG>, and check if the latest call will continue a
266 multibyte sequence. When a character is <EM>complete</EM>, ncurses displays the
267 character and moves to the next position in the screen.
269 If the calling application interrupts the succession of bytes in a
270 multibyte character by moving the current location (e.g., using <STRONG>wmove</STRONG>),
271 ncurses discards the partially built character, starting over again.
273 For portability to other implementations, do not rely upon this
276 <STRONG>o</STRONG> check if a character can be represented as a single byte in the
277 current locale before attempting call <STRONG>waddch</STRONG>, and
279 <STRONG>o</STRONG> call <STRONG>wadd_wch</STRONG> for characters which cannot be handled by <STRONG>waddch</STRONG>.
282 </PRE><H3><a name="h3-TABSIZE">TABSIZE</a></H3><PRE>
283 The <STRONG>TABSIZE</STRONG> variable is implemented in SVr4 and other versions of
284 curses, but is not part of X/Open curses (see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG> for
287 If <EM>ch</EM> is a carriage return, the cursor is moved to the beginning of the
288 current row of the window. This is true of other implementations, but
292 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
293 <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>,
294 <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><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>putc(3)</STRONG>.
296 Comparable functions in the wide-character (ncursesw) library are
297 described in <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>.
301 <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
305 <li><a href="#h2-NAME">NAME</a></li>
306 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
307 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
309 <li><a href="#h3-Adding-characters">Adding characters</a></li>
310 <li><a href="#h3-Echoing-characters">Echoing characters</a></li>
311 <li><a href="#h3-Line-Graphics">Line Graphics</a></li>
314 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
315 <li><a href="#h2-NOTES">NOTES</a></li>
316 <li><a href="#h2-PORTABILITY">PORTABILITY</a>
318 <li><a href="#h3-ACS-Symbols">ACS Symbols</a></li>
319 <li><a href="#h3-Character-Set">Character Set</a></li>
320 <li><a href="#h3-TABSIZE">TABSIZE</a></li>
323 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>