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+ * Copyright 2019-2023,2024 Thomas E. Dickey *
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- * @Id: curs_getcchar.3x,v 1.16 2012/11/03 23:03:59 tom Exp @
+ * @Id: curs_getcchar.3x,v 1.47 2024/04/13 22:08:22 tom Exp @
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-<H1 class="no-header">curs_getcchar 3x</H1>
+<H1 class="no-header">curs_getcchar 3x 2024-04-13 ncurses 6.4 Library calls</H1>
<PRE>
-<STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>
<STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>
+<STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>
Library calls <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>
-</PRE>
-<H2><a name="h2-NAME">NAME</a></H2><PRE>
- <STRONG>getcchar</STRONG>, <STRONG>setcchar</STRONG> - Get a wide character string and ren-
- dition from a <STRONG>cchar_t</STRONG> or set a <STRONG>cchar_t</STRONG> from a wide-charac-
- ter string
+</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
+ <STRONG>getcchar</STRONG>, <STRONG>setcchar</STRONG> - convert between a wide-character string and a
+ <EM>curses</EM> complex character
-</PRE>
-<H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
+</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>int</STRONG> <STRONG>getcchar(</STRONG>
<STRONG>const</STRONG> <STRONG>wchar_t</STRONG> <STRONG>*</STRONG><EM>wch</EM><STRONG>,</STRONG>
<STRONG>const</STRONG> <STRONG>attr_t</STRONG> <EM>attrs</EM><STRONG>,</STRONG>
<STRONG>short</STRONG> <EM>color</EM><STRONG>_</STRONG><EM>pair</EM><STRONG>,</STRONG>
- <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM> <STRONG>);</STRONG>
+ <STRONG>const</STRONG> <STRONG>void</STRONG> <STRONG>*</STRONG><EM>opts</EM> <STRONG>);</STRONG>
-</PRE>
-<H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
- The <STRONG>getcchar</STRONG> function gets a wide-character string and
- rendition from a <STRONG>cchar_t</STRONG> argument. When <EM>wch</EM> is not a null
- pointer, the <STRONG>getcchar</STRONG> function does the following:
+</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
+
+</PRE><H3><a name="h3-getcchar">getcchar</a></H3><PRE>
+ The <STRONG>getcchar</STRONG> function gets a wide-character string and rendition from a
+ <STRONG>cchar_t</STRONG> argument. When <EM>wch</EM> is not a null pointer, the <STRONG>getcchar</STRONG>
+ function does the following:
<STRONG>o</STRONG> Extracts information from a <STRONG>cchar_t</STRONG> value <EM>wcval</EM>
- <STRONG>o</STRONG> Stores the character attributes in the location
- pointed to by <EM>attrs</EM>
+ <STRONG>o</STRONG> Stores the character attributes in the location pointed to by <EM>attrs</EM>
- <STRONG>o</STRONG> Stores the color-pair in the location pointed to by
- <EM>color</EM><STRONG>_</STRONG><EM>pair</EM>
+ <STRONG>o</STRONG> Stores the color pair in the location pointed to by <EM>color</EM><STRONG>_</STRONG><EM>pair</EM>
- <STRONG>o</STRONG> Stores the wide-character string, characters refer-
- enced by <EM>wcval</EM>, into the array pointed to by <EM>wch</EM>.
+ <STRONG>o</STRONG> Stores the wide-character string, characters referenced by <EM>wcval</EM>,
+ into the array pointed to by <EM>wch</EM>.
- When <EM>wch</EM> is a null pointer, the <STRONG>getcchar</STRONG> function does the
- following:
+ When <EM>wch</EM> is a null pointer, the <STRONG>getcchar</STRONG> function does the following:
- <STRONG>o</STRONG> Obtains the number of wide characters pointed to by
- <EM>wcval</EM>
+ <STRONG>o</STRONG> Obtains the number of wide characters pointed to by <EM>wcval</EM>
- <STRONG>o</STRONG> Does not change the data referenced by <EM>attrs</EM> or
- <EM>color</EM><STRONG>_</STRONG><EM>pair</EM>
+ <STRONG>o</STRONG> Does not change the data referenced by <EM>attrs</EM> or <EM>color</EM><STRONG>_</STRONG><EM>pair</EM>
- The <STRONG>setcchar</STRONG> function initializes the location pointed to
- by <EM>wcval</EM> by using:
+
+</PRE><H3><a name="h3-setcchar">setcchar</a></H3><PRE>
+ The <STRONG>setcchar</STRONG> function initializes the location pointed to by <EM>wcval</EM> by
+ using:
<STRONG>o</STRONG> The character attributes in <EM>attrs</EM>
<STRONG>o</STRONG> The color pair in <EM>color</EM><STRONG>_</STRONG><EM>pair</EM>
- <STRONG>o</STRONG> The wide-character string pointed to by <EM>wch</EM>. The
- string must be L'\0' terminated, contain at most one
- spacing character, which must be the first.
+ <STRONG>o</STRONG> The wide-character string pointed to by <EM>wch</EM>. The string must be
+ L'\0' terminated, contain at most one spacing character, which must
+ be the first.
- Up to <STRONG>CCHARW_MAX</STRONG>-1 nonspacing characters may follow.
- Additional nonspacing characters are ignored.
+ Up to <STRONG>CCHARW_MAX</STRONG>-1 non-spacing characters may follow. Additional
+ non-spacing characters are ignored.
- The string may contain a single control character
- instead. In that case, no nonspacing characters are
- allowed.
+ The string may contain a single control character instead. In that
+ case, no non-spacing characters are allowed.
-</PRE>
-<H2><a name="h2-NOTES">NOTES</a></H2><PRE>
- The <EM>opts</EM> argument is reserved for future use. Currently,
- an application must provide a null pointer as <EM>opts</EM>.
+</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+ When <EM>wch</EM> is a null pointer, <STRONG>getcchar</STRONG> returns the number of wide
+ characters referenced by <EM>wcval</EM>, including one for a trailing null.
- The <EM>wcval</EM> argument may be a value generated by a call to
- <STRONG>setcchar</STRONG> or by a function that has a <STRONG>cchar_t</STRONG> output argu-
- ment. If <EM>wcval</EM> is constructed by any other means, the
- effect is unspecified.
+ When <EM>wch</EM> is not a null pointer, <STRONG>getcchar</STRONG> returns <STRONG>OK</STRONG> upon successful
+ completion, and <STRONG>ERR</STRONG> otherwise.
+ Upon successful completion, <STRONG>setcchar</STRONG> returns <STRONG>OK</STRONG>. Otherwise, it returns
+ <STRONG>ERR</STRONG>.
-</PRE>
-<H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- When <EM>wch</EM> is a null pointer, <STRONG>getcchar</STRONG> returns the number of
- wide characters referenced by <EM>wcval</EM>, including one for a
- trailing null.
- When <EM>wch</EM> is not a null pointer, <STRONG>getcchar</STRONG> returns <STRONG>OK</STRONG> upon
- successful completion, and <STRONG>ERR</STRONG> otherwise.
+</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
+ The <EM>wcval</EM> argument may be a value generated by a call to <STRONG>setcchar</STRONG> or by
+ a function that has a <STRONG>cchar_t</STRONG> output argument. If <EM>wcval</EM> is constructed
+ by any other means, the effect is unspecified.
- Upon successful completion, <STRONG>setcchar</STRONG> returns <STRONG>OK</STRONG>. Other-
- wise, it returns <STRONG>ERR</STRONG>.
+</PRE><H2><a name="h2-EXTENSIONS">EXTENSIONS</a></H2><PRE>
+ X/Open Curses documents the <EM>opts</EM> argument as reserved for future use,
+ saying that it must be null. This implementation uses that parameter
+ in ABI 6 for the functions which have a color pair parameter to support
+ extended color pairs:
-</PRE>
-<H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
- 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>.
+ <STRONG>o</STRONG> For functions which modify the color, e.g., <STRONG>setcchar</STRONG>, if <EM>opts</EM> is
+ set it is treated as a pointer to <STRONG>int</STRONG>, and used to set the color
+ pair instead of the <STRONG>short</STRONG> pair parameter.
+
+ <STRONG>o</STRONG> For functions which retrieve the color, e.g., <STRONG>getcchar</STRONG>, if <EM>opts</EM> is
+ set it is treated as a pointer to <STRONG>int</STRONG>, and used to retrieve the
+ color pair as an <STRONG>int</STRONG> value, in addition retrieving it via the
+ standard pointer to <STRONG>short</STRONG> parameter.
+
+
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ The <STRONG>CCHARW_MAX</STRONG> symbol is specific to <EM>ncurses</EM>. X/Open Curses does not
+ provide details for the layout of the <STRONG>cchar_t</STRONG> structure. It tells what
+ data are stored in it:
+
+ <STRONG>o</STRONG> a spacing character (<STRONG>wchar_t</STRONG>, i.e., 32-bits).
+
+ <STRONG>o</STRONG> non-spacing characters (again, <STRONG>wchar_t</STRONG>'s).
+
+ <STRONG>o</STRONG> attributes (at least 16 bits, inferred from the various ACS- and
+ WACS-flags).
+ <STRONG>o</STRONG> color pair (at least 16 bits, inferred from the <STRONG>unsigned</STRONG> <STRONG>short</STRONG>
+ type).
+ The non-spacing characters are optional, in the sense that zero or more
+ may be stored in a <STRONG>cchar_t</STRONG>. XOpen/Curses specifies a limit:
- <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>
+ Implementations may limit the number of non-spacing characters that
+ can be associated with a spacing character, provided any limit is
+ at least 5.
+
+ The Unix implementations at the time follow that limit:
+
+ <STRONG>o</STRONG> AIX 4 and OSF1 4 use the same declaration with an array of 5 non-
+ spacing characters <EM>z</EM> and a single spacing character <EM>c</EM>.
+
+ <STRONG>o</STRONG> HP-UX 10 uses an opaque structure with 28 bytes, which is large
+ enough for the 6 <STRONG>wchar_t</STRONG> values.
+
+ <STRONG>o</STRONG> Solaris <EM>xpg4</EM> curses uses a single array of 6 <STRONG>wchar_t</STRONG> values.
+
+ This implementation's <STRONG>cchar_t</STRONG> was defined in 1995 using <STRONG>5</STRONG> for the total
+ of spacing and non-spacing characters (<STRONG>CCHARW_MAX</STRONG>). That was probably
+ due to a misreading of the AIX 4 header files, because the X/Open
+ Curses document was not generally available at that time. Later (in
+ 2002), this detail was overlooked when beginning to implement the
+ functions using the structure.
+
+ In practice, even four non-spacing characters may seem enough. X/Open
+ Curses documents possible uses for non-spacing characters, including
+ using them for ligatures between characters (a feature apparently not
+ supported by any curses implementation). Unicode does not limit the
+ (analogous) number of combining characters, so some applications may be
+ affected.
+
+
+</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
+ <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_color.3x.html">curs_color(3x)</A></STRONG>, <STRONG>wcwidth(3)</STRONG>
+
+
+
+ncurses 6.4 2024-04-13 <STRONG><A HREF="curs_getcchar.3x.html">curs_getcchar(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-NAME">NAME</a></li>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
-<li><a href="#h2-DESCRIPTION">DESCRIPTION</a></li>
-<li><a href="#h2-NOTES">NOTES</a></li>
+<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
+<ul>
+<li><a href="#h3-getcchar">getcchar</a></li>
+<li><a href="#h3-setcchar">setcchar</a></li>
+</ul>
+</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
+<li><a href="#h2-NOTES">NOTES</a></li>
+<li><a href="#h2-EXTENSIONS">EXTENSIONS</a></li>
+<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
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