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29 * @Id: curs_getcchar.3x,v 1.23 2019/11/30 22:22:32 tom Exp @
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41 <H1 class="no-header">curs_getcchar 3x</H1>
43 <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG> <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>
48 </PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
49 <STRONG>getcchar</STRONG>, <STRONG>setcchar</STRONG> - Get a wide character string and rendition from a
50 <STRONG>cchar_t</STRONG> or set a <STRONG>cchar_t</STRONG> from a wide-character string
53 </PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
54 <STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
56 <STRONG>int</STRONG> <STRONG>getcchar(</STRONG>
57 <STRONG>const</STRONG> <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wcval</EM><STRONG>,</STRONG>
58 <STRONG>wchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>,</STRONG>
59 <STRONG>attr_t</STRONG> <STRONG>*</STRONG><EM>attrs</EM><STRONG>,</STRONG>
60 <STRONG>short</STRONG> <STRONG>*</STRONG><EM>color</EM><STRONG>_</STRONG><EM>pair</EM><STRONG>,</STRONG>
61 <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM> <STRONG>);</STRONG>
63 <STRONG>int</STRONG> <STRONG>setcchar(</STRONG>
64 <STRONG>cchar_t</STRONG> <STRONG>*</STRONG><EM>wcval</EM><STRONG>,</STRONG>
65 <STRONG>const</STRONG> <STRONG>wchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>,</STRONG>
66 <STRONG>const</STRONG> <STRONG>attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG>
67 <STRONG>short</STRONG> <EM>color</EM><STRONG>_</STRONG><EM>pair</EM><STRONG>,</STRONG>
68 <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM> <STRONG>);</STRONG>
71 </PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
73 </PRE><H3><a name="h3-getcchar">getcchar</a></H3><PRE>
74 The <STRONG>getcchar</STRONG> function gets a wide-character string and rendition from a
75 <STRONG>cchar_t</STRONG> argument. When <EM>wch</EM> is not a null pointer, the <STRONG>getcchar</STRONG> func-
76 tion does the following:
78 <STRONG>o</STRONG> Extracts information from a <STRONG>cchar_t</STRONG> value <EM>wcval</EM>
80 <STRONG>o</STRONG> Stores the character attributes in the location pointed to by <EM>attrs</EM>
82 <STRONG>o</STRONG> Stores the color-pair in the location pointed to by <EM>color</EM><STRONG>_</STRONG><EM>pair</EM>
84 <STRONG>o</STRONG> Stores the wide-character string, characters referenced by <EM>wcval</EM>,
85 into the array pointed to by <EM>wch</EM>.
87 When <EM>wch</EM> is a null pointer, the <STRONG>getcchar</STRONG> function does the following:
89 <STRONG>o</STRONG> Obtains the number of wide characters pointed to by <EM>wcval</EM>
91 <STRONG>o</STRONG> Does not change the data referenced by <EM>attrs</EM> or <EM>color</EM><STRONG>_</STRONG><EM>pair</EM>
94 </PRE><H3><a name="h3-setcchar">setcchar</a></H3><PRE>
95 The <STRONG>setcchar</STRONG> function initializes the location pointed to by <EM>wcval</EM> by
98 <STRONG>o</STRONG> The character attributes in <EM>attrs</EM>
100 <STRONG>o</STRONG> The color pair in <EM>color</EM><STRONG>_</STRONG><EM>pair</EM>
102 <STRONG>o</STRONG> The wide-character string pointed to by <EM>wch</EM>. The string must be
103 L'\0' terminated, contain at most one spacing character, which must
106 Up to <STRONG>CCHARW_MAX</STRONG>-1 nonspacing characters may follow. Additional
107 nonspacing characters are ignored.
109 The string may contain a single control character instead. In that
110 case, no nonspacing characters are allowed.
113 </PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
114 X/Open Curses documents the <EM>opts</EM> argument as reserved for future use,
115 saying that it must be null. This implementation uses that parameter
116 in ABI 6 for the functions which have a color-pair parameter to support
117 extended color pairs:
119 <STRONG>o</STRONG> For functions which modify the color, e.g., <STRONG>setcchar</STRONG>, if <EM>opts</EM> is
120 set it is treated as a pointer to <STRONG>int</STRONG>, and used to set the color
121 pair instead of the <STRONG>short</STRONG> pair parameter.
123 <STRONG>o</STRONG> For functions which retrieve the color, e.g., <STRONG>getcchar</STRONG>, if <EM>opts</EM> is
124 set it is treated as a pointer to <STRONG>int</STRONG>, and used to retrieve the
125 color pair as an <STRONG>int</STRONG> value, in addition retrieving it via the stan-
126 dard pointer to <STRONG>short</STRONG> parameter.
129 </PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
130 The <EM>wcval</EM> argument may be a value generated by a call to <STRONG>setcchar</STRONG> or by
131 a function that has a <STRONG>cchar_t</STRONG> output argument. If <EM>wcval</EM> is constructed
132 by any other means, the effect is unspecified.
135 </PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
136 When <EM>wch</EM> is a null pointer, <STRONG>getcchar</STRONG> returns the number of wide charac-
137 ters referenced by <EM>wcval</EM>, including one for a trailing null.
139 When <EM>wch</EM> is not a null pointer, <STRONG>getcchar</STRONG> returns <STRONG>OK</STRONG> upon successful
140 completion, and <STRONG>ERR</STRONG> otherwise.
142 Upon successful completion, <STRONG>setcchar</STRONG> returns <STRONG>OK</STRONG>. Otherwise, it returns
143 <STRONG>ERR</STRONG>.
146 </PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
147 The <STRONG>CCHARW_MAX</STRONG> symbol is specific to ncurses. X/Open Curses does not
148 provide details for the layout of the <STRONG>cchar_t</STRONG> structure. It tells what
149 data are stored in it:
151 <STRONG>o</STRONG> a spacing character (<STRONG>wchar_t</STRONG>, i.e., 32-bits).
153 <STRONG>o</STRONG> non-spacing characters (again, <STRONG>wchar_t</STRONG>'s).
155 <STRONG>o</STRONG> attributes (at least 16 bits, inferred from the various ACS- and
158 <STRONG>o</STRONG> color pair (at least 16 bits, inferred from the <STRONG>unsigned</STRONG> <STRONG>short</STRONG>
161 The non-spacing characters are optional, in the sense that zero or more
162 may be stored in a <STRONG>cchar_t</STRONG>. XOpen/Curses specifies a limit:
164 Implementations may limit the number of non-spacing characters that
165 can be associated with a spacing character, provided any limit is
168 The Unix implementations at the time follow that limit:
170 <STRONG>o</STRONG> AIX 4 and OSF1 4 use the same declaration with an array of 5 non-
171 spacing characters <EM>z</EM> and a single spacing character <EM>c</EM>.
173 <STRONG>o</STRONG> HP-UX 10 uses an opaque structure with 28 bytes, which is large
174 enough for the 6 <STRONG>wchar_t</STRONG> values.
176 <STRONG>o</STRONG> Solaris xpg4 curses uses a single array of 6 <STRONG>wchar_t</STRONG> values.
178 This implementation's <STRONG>cchar_t</STRONG> was defined in 1995 using <STRONG>5</STRONG> for the total
179 of spacing and non-spacing characters (<STRONG>CCHARW_MAX</STRONG>). That was probably
180 due to a misreading of the AIX 4 header files, because the X/Open
181 Curses document was not generally available at that time. Later (in
182 2002), this detail was overlooked when beginning to implement the func-
183 tions using the structure.
185 In practice, even four non-spacing characters may seem enough. X/Open
186 Curses documents possible uses for non-spacing characters, including
187 using them for ligatures between characters (a feature apparently not
188 supported by any curses implementation). Unicode does not limit the
189 (analogous) number of combining characters, so some applications may be
193 </PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
194 Functions: <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_color.3x.html">curs_color(3x)</A></STRONG>, <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG>wcwidth(3)</STRONG>.
198 <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>
202 <li><a href="#h2-NAME">NAME</a></li>
203 <li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
204 <li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
206 <li><a href="#h3-getcchar">getcchar</a></li>
207 <li><a href="#h3-setcchar">setcchar</a></li>
210 <li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
211 <li><a href="#h2-NOTES">NOTES</a></li>
212 <li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
213 <li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
214 <li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>