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</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.
+ gous <EM>WACS</EM><STRONG>_</STRONG> definitions which are <STRONG>cchar_t</STRONG> constants. Some implementa-
+ tions are problematic:
+
+ <STRONG>o</STRONG> Some implementations define the ACS symbols to a constant (such as
+ Solaris), while others define those to entries in an array.
+
+ This implementation uses an array <STRONG>acs_map</STRONG>, as done in SVr4 curses.
+ NetBSD also uses an array, actually named <STRONG>_acs_char</STRONG>, with a <STRONG>#define</STRONG>
+ for compatibility.
+
+ <STRONG>o</STRONG> HPUX curses equates some of the <EM>ACS</EM><STRONG>_</STRONG> symbols to the analogous <EM>WACS</EM><STRONG>_</STRONG>
+ symbols as if the <EM>ACS</EM><STRONG>_</STRONG> symbols were wide characters. The misde-
+ fined symbols are the arrows and other symbols which are not used
+ for line-drawing.
+
+ <STRONG>o</STRONG> X/Open Curses (issues 2 through 7) has a typographical error for
+ the ACS_LANTERN symbol, equating its "VT100+ Character" to <STRONG>I</STRONG> (capi-
+ tal I), while the header files for SVr4 curses and the various
+ implementations use <STRONG>i</STRONG> (lowercase).
+
+ None of the terminal descriptions on Unix platforms use uppercase-
+ I, except for Solaris (i.e., <EM>screen</EM>'s terminal description, appar-
+ ently based on the X/Open documentation around 1995). On the other
+ hand, the terminal description <EM>gs6300</EM> (AT&T PC6300 with EMOTS Ter-
+ minal Emulator) uses lowercase-i.
Some ACS symbols (ACS_S3, ACS_S7, ACS_LEQUAL, ACS_GEQUAL, ACS_PI,
ACS_NEQUAL, ACS_STERLING) were not documented in any publicly released
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.
+ In this implementation, <STRONG>chtype</STRONG> holds an eight-bit character. 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
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