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-<H1 class="no-header">curs_inch 3x 2024-05-11 ncurses 6.5 Library calls</H1>
+<H1 class="no-header">curs_inch 3x 2024-06-08 ncurses 6.5 Library calls</H1>
<PRE>
<STRONG><A HREF="curs_inch.3x.html">curs_inch(3x)</A></STRONG> Library calls <STRONG><A HREF="curs_inch.3x.html">curs_inch(3x)</A></STRONG>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
<STRONG>chtype</STRONG> <STRONG>inch(void);</STRONG>
- <STRONG>chtype</STRONG> <STRONG>winch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>);</STRONG>
+ <STRONG>chtype</STRONG> <STRONG>winch(WINDOW</STRONG> <STRONG>*</STRONG> <EM>win</EM><STRONG>);</STRONG>
<STRONG>chtype</STRONG> <STRONG>mvinch(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>);</STRONG>
- <STRONG>chtype</STRONG> <STRONG>mvwinch(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>chtype</STRONG> <STRONG>mvwinch(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>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
- <STRONG>winch</STRONG> returns the <EM>curses</EM> character, including rendering attributes and
- color pair identifier, at the cursor position in the window <EM>win</EM>.
- Subsection "Video Attributes" of <STRONG><A HREF="curs_attr.3x.html">attron(3x)</A></STRONG> explains how to extract
- these data from a <EM>chtype</EM>. <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> describes the variants of this
- function.
+ <STRONG>winch</STRONG> returns the <EM>curses</EM> character, including its attributes and color
+ pair identifier, at the cursor position in the window <EM>win</EM>. Subsection
+ "Video Attributes" of <STRONG><A HREF="curs_attr.3x.html">attron(3x)</A></STRONG> explains how to extract these data
+ from a <EM>chtype</EM>. <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> describes the variants of this function.
</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
- Functions prefixed with "mv" first perform cursor movement and fail if
- the position (<EM>y</EM>, <EM>x</EM>) is outside the window boundaries.
+ These functions return <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on failure.
+
+ In <EM>ncurses</EM>, <STRONG>winch</STRONG> returns <STRONG>ERR</STRONG> if <EM>win</EM> is <STRONG>NULL</STRONG>.
- These functions do not return an error if the window comprises cells of
- <EM>curses</EM> complex characters (that is, they contain characters with codes
- wider than eight bits, or greater than 255 as an unsigned decimal
- integer). They instead extract only the low-order eight bits of
- character data in the cell.
+ Functions prefixed with "mv" first perform cursor movement and fail if
+ the position (<EM>y</EM>, <EM>x</EM>) is outside the window boundaries.
</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
<STRONG>inch</STRONG>, <STRONG>mvinch</STRONG>, and <STRONG>mvwinch</STRONG> may be implemented as macros.
+ These functions do not fail if the window contains cells of <EM>curses</EM>
+ complex characters; that is, if they contain characters with codes
+ wider than eight bits (or greater than 255 as an unsigned decimal
+ integer). They instead extract only the low-order eight bits of the
+ character code from the cell.
+
</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
- X/Open Curses, Issue 4 describes these functions. It specifies no
+ X/Open Curses, Issue 4 describes these functions. It specifies no
error conditions for them.
</PRE><H2><a name="h2-HISTORY">HISTORY</a></H2><PRE>
- <STRONG>winch</STRONG> was implemented in the original 4BSD <EM>curses</EM> library (November
- 1980). It returned only the character code (as an integer) with the
- "standout" attribute bit (the only one it supported) cleared. Because
- 7-bit ASCII was the only character encoding supported, 4BSD's <STRONG>winch</STRONG>
- returned a <EM>char</EM> type.
-
- System V <EM>curses</EM> (1983) permitted several rendering attributes to be
- combined with a character in a window. Reflecting this improvement,
- <STRONG>winch</STRONG> returned an <EM>int</EM> in SVr3.2 (1988) and switched to <EM>chtype</EM> in SVr4
- (1989).
-
- X/Open Curses does not specify the sizes of the character code or color
- pair identifier, nor the quantity of rendering attribute bits, in
- <EM>chtype</EM>; these are implementation-dependent. <EM>ncurses</EM> uses eight bits
- for the character code. An application requiring a wider character
- type, for instance to handle Unicode, should use the wide-character
- counterparts of these functions.
+ The original <EM>curses</EM> in 4BSD (1980) defined <EM>winch</EM> as a macro accessing
+ the <EM>WINDOW</EM> structure member representing character cell data, at that
+ time a <EM>char</EM>, containing only a 7-bit ASCII character code and a
+ "standout" attribute bit, the only one the library supported.
+
+ SVr2 <EM>curses</EM> (1984) extended this approach, widening the character code
+ to eight bits and permitting several attributes to be combined with it
+ by storing them together in a <EM>chtype</EM>, an alias of <EM>unsigned</EM> <EM>short</EM>.
+ Because a macro was used, its value was not type-checked as a function
+ return value could have been. Goodheart documented SVr3 (1987) <EM>winch</EM>
+ as returning an <EM>int</EM>. SVr3.1's (1987) <EM>chtype</EM> became an alias of
+ <EM>unsigned</EM> <EM>long</EM>, using 16 bits for the character code and widening the
+ type in practical terms to 32 bits, as 64-bit Unix systems were not yet
+ in wide use, and fixed-width integral types would not be standard until
+ ISO C99. SVr3.2 (1988) added a 6-bit color pair identifier alongside
+ the attributes.
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
-ncurses 6.5 2024-05-11 <STRONG><A HREF="curs_inch.3x.html">curs_inch(3x)</A></STRONG>
+ncurses 6.5 2024-06-08 <STRONG><A HREF="curs_inch.3x.html">curs_inch(3x)</A></STRONG>
</PRE>
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