- 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.
+ X/Open Curses states that the <I>ACS</I><B>_</B> definitions are <B>char</B> constants. For
+ the wide-character implementation (see <B>curs_add_wch</B>), there are
+ analogous <I>WACS</I><B>_</B> definitions which are <B>cchar_t</B> constants. Some
+ implementations are problematic:
+
+ <B>o</B> 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 <B>acs_map</B>, as done in SVr4 curses.
+ NetBSD also uses an array, actually named <B>_acs_char</B>, with a <B>#define</B>
+ for compatibility.
+
+ <B>o</B> HPUX curses equates some of the <I>ACS</I><B>_</B> symbols to the analogous <I>WACS</I><B>_</B>
+ symbols as if the <I>ACS</I><B>_</B> symbols were wide characters. The
+ misdefined symbols are the arrows and other symbols which are not
+ used for line-drawing.
+
+ <B>o</B> X/Open Curses (issues 2 through 7) has a typographical error for
+ the ACS_LANTERN symbol, equating its "VT100+ Character" to <B>I</B>
+ (capital I), while the header files for SVr4 curses and the various
+ implementations use <B>i</B> (lowercase).
+
+ None of the terminal descriptions on Unix platforms use uppercase-
+ I, except for Solaris (i.e., <I>screen</I>'s terminal description,
+ apparently based on the X/Open documentation around 1995). On the
+ other hand, the terminal description <I>gs6300</I> (AT&T PC6300 with EMOTS
+ Terminal Emulator) uses lowercase-i.