<!--
* t
****************************************************************************
- * Copyright (c) 1998-2015,2017 Free Software Foundation, Inc. *
+ * Copyright (c) 1998-2018,2019 Free Software Foundation, Inc. *
* *
* Permission is hereby granted, free of charge, to any person obtaining a *
* copy of this software and associated documentation files (the *
* sale, use or other dealings in this Software without prior written *
* authorization. *
****************************************************************************
- * @Id: curs_addch.3x,v 1.41 2017/05/05 18:15:29 tom Exp @
+ * @Id: curs_addch.3x,v 1.47 2019/02/16 23:50:17 tom Exp @
-->
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN">
<HTML>
<HEAD>
<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
-<meta name="generator" content="Manpage converted by man2html - see http://invisible-island.net/scripts/readme.html#others_scripts">
+<meta name="generator" content="Manpage converted by man2html - see https://invisible-island.net/scripts/readme.html#others_scripts">
<TITLE>curs_addch 3x</TITLE>
-<link rev=made href="mailto:bug-ncurses@gnu.org">
+<link rel="author" href="mailto:bug-ncurses@gnu.org">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
</HEAD>
<BODY>
The defaults specified for forms-drawing characters apply in the POSIX
locale.
+
+</PRE><H3><a name="h3-ACS-Symbols">ACS Symbols</a></H3><PRE>
X/Open Curses states that the <EM>ACS</EM><STRONG>_</STRONG> definitions are <STRONG>char</STRONG> constants. For
the wide-character implementation (see <STRONG>curs_add_wch</STRONG>), there are analo-
gous <EM>WACS</EM><STRONG>_</STRONG> definitions which are <STRONG>cchar_t</STRONG> constants.
acters except by using UTF-8 (see the discussion of <STRONG>NCURSES_NO_UTF8_ACS</STRONG>
in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>).
- The <STRONG>TABSIZE</STRONG> variable is implemented in some versions of curses, but is
- not part of X/Open curses.
+
+</PRE><H3><a name="h3-Character-Set">Character Set</a></H3><PRE>
+ X/Open Curses assumes that the parameter passed to <STRONG>waddch</STRONG> contains a
+ single character. As discussed in <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, that character may
+ have been more than eight bits in an SVr3 or SVr4 implementation, but
+ in the X/Open Curses model, the details are not given. The important
+ distinction between SVr4 curses and X/Open Curses is that the non-char-
+ acter information (attributes and color) was separated from the charac-
+ ter information which is packed in a <STRONG>chtype</STRONG> to pass to <STRONG>waddch</STRONG>.
+
+ In this implementation, <STRONG>chtype</STRONG> holds eight bits. But ncurses allows
+ multibyte characters to be passed in a succession of calls to <STRONG>waddch</STRONG>.
+ The other implementations do not do this; a call to <STRONG>waddch</STRONG> passes
+ exactly one character which may be rendered as one or more cells on the
+ screen depending on whether it is printable.
+
+ Depending on the locale settings, ncurses will inspect the byte passed
+ in each call to <STRONG>waddch</STRONG>, and check if the latest call will continue a
+ multibyte sequence. When a character is <EM>complete</EM>, ncurses displays the
+ character and moves to the next position in the screen.
+
+ If the calling application interrupts the succession of bytes in a
+ multibyte character by moving the current location (e.g., using <STRONG>wmove</STRONG>),
+ ncurses discards the partially built character, starting over again.
+
+ For portability to other implementations, do not rely upon this behav-
+ ior:
+
+ <STRONG>o</STRONG> check if a character can be represented as a single byte in the
+ current locale before attempting call <STRONG>waddch</STRONG>, and
+
+ <STRONG>o</STRONG> call <STRONG>wadd_wch</STRONG> for characters which cannot be handled by <STRONG>waddch</STRONG>.
+
+
+</PRE><H3><a name="h3-TABSIZE">TABSIZE</a></H3><PRE>
+ The <STRONG>TABSIZE</STRONG> variable is implemented in SVr4 and other versions of
+ curses, but is not part of X/Open curses (see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG> for
+ more details).
If <EM>ch</EM> is a carriage return, the cursor is moved to the beginning of the
current row of the window. This is true of other implementations, but
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
<li><a href="#h2-NOTES">NOTES</a></li>
-<li><a href="#h2-PORTABILITY">PORTABILITY</a></li>
+<li><a href="#h2-PORTABILITY">PORTABILITY</a>
+<ul>
+<li><a href="#h3-ACS-Symbols">ACS Symbols</a></li>
+<li><a href="#h3-Character-Set">Character Set</a></li>
+<li><a href="#h3-TABSIZE">TABSIZE</a></li>
+</ul>
+</li>
<li><a href="#h2-SEE-ALSO">SEE ALSO</a></li>
</ul>
</div>
projects / ncurses.git / blobdiff