+</PRE><H3><a name="h3-Echoing-characters">Echoing characters</a></H3><PRE>
+ The <STRONG>echochar</STRONG> and <STRONG>wechochar</STRONG> routines are equivalent to a call to <STRONG>addch</STRONG>
+ followed by a call to <STRONG><A HREF="curs_refresh.3x.html">refresh(3x)</A></STRONG>, or a call to <STRONG>waddch</STRONG> followed by a
+ call to <STRONG>wrefresh</STRONG>. The knowledge that only a single character is being
+ output is used and, for non-control characters, a considerable perfor-
+ mance gain may be seen by using these routines instead of their equiva-
+ lents.
+
+
+</PRE><H3><a name="h3-Line-Graphics">Line Graphics</a></H3><PRE>
+ The following variables may be used to add line drawing characters to
+ the screen with routines of the <STRONG>addch</STRONG> family. The default character
+ listed below is used if the <STRONG>acsc</STRONG> capability does not define a terminal-
+ specific replacement for it, or if the terminal and locale configura-
+ tion requires Unicode but the library is unable to use Unicode.
+
+ The names are taken from VT100 nomenclature.
+
+ <STRONG>ACS</STRONG> <STRONG>ACS</STRONG> <STRONG>acsc</STRONG> <STRONG>Glyph</STRONG>
+ <STRONG>Name</STRONG> <STRONG>Default</STRONG> <STRONG>char</STRONG> <STRONG>Name</STRONG>
+ ---------------------------------------------------------
+ ACS_BLOCK # 0 solid square block
+ ACS_BOARD # h board of squares
+ ACS_BTEE + v bottom tee
+ ACS_BULLET o ~ bullet
+ ACS_CKBOARD : a checker board (stipple)
+ ACS_DARROW v . arrow pointing down
+ ACS_DEGREE ' f degree symbol
+ ACS_DIAMOND + ` diamond
+ ACS_GEQUAL > > greater-than-or-equal-to
+ ACS_HLINE - q horizontal line
+ ACS_LANTERN # i lantern symbol
+ ACS_LARROW < , arrow pointing left
+ ACS_LEQUAL < y less-than-or-equal-to
+ ACS_LLCORNER + m lower left-hand corner
+ ACS_LRCORNER + j lower right-hand corner
+ ACS_LTEE + t left tee
+ ACS_NEQUAL ! | not-equal
+ ACS_PI * { greek pi
+ ACS_PLMINUS # g plus/minus
+ ACS_PLUS + n plus
+ ACS_RARROW > + arrow pointing right
+ ACS_RTEE + u right tee
+ ACS_S1 - o scan line 1
+ ACS_S3 - p scan line 3
+ ACS_S7 - r scan line 7
+ ACS_S9 _ s scan line 9
+ ACS_STERLING f } pound-sterling symbol
+ ACS_TTEE + w top tee
+ ACS_UARROW ^ - arrow pointing up
+ ACS_ULCORNER + l upper left-hand corner
+ ACS_URCORNER + k upper right-hand corner
+ ACS_VLINE | x vertical line
+
+
+</PRE><H2><a name="h2-RETURN-VALUE">RETURN VALUE</a></H2><PRE>
+ All routines return the integer <STRONG>ERR</STRONG> upon failure and <STRONG>OK</STRONG> on success (the
+ SVr4 manuals specify only "an integer value other than <STRONG>ERR</STRONG>") upon suc-
+ cessful completion, unless otherwise noted in the preceding routine
+ descriptions.
+
+ Functions with a "mv" prefix first perform a cursor movement using
+ <STRONG>wmove</STRONG>, and return an error if the position is outside the window, or if
+ the window pointer is null.
+
+ If it is not possible to add a complete character, an error is
+ returned:
+
+ <STRONG>o</STRONG> If <STRONG>scrollok</STRONG> is not enabled, writing a character at the lower right
+ margin succeeds. However, an error is returned because it is not
+ possible to wrap to a new line
+
+ <STRONG>o</STRONG> If an error is detected when converting a multibyte character to a
+ sequence of bytes, or if it is not possible to add all of the
+ resulting bytes in the window, an error is returned.
+
+
+</PRE><H2><a name="h2-NOTES">NOTES</a></H2><PRE>
+ Note that <STRONG>addch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, and <STRONG>echochar</STRONG> may be macros.
+
+
+</PRE><H2><a name="h2-PORTABILITY">PORTABILITY</a></H2><PRE>
+ All these functions are described in the XSI Curses standard, Issue 4.
+ 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. 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
+ System V. However, many publicly available terminfos include <STRONG>acsc</STRONG>
+ strings in which their key characters (pryz{|}) are embedded, and a
+ second-hand list of their character descriptions has come to light.
+ The ACS-prefixed names for them were invented for <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>.
+
+ The <EM>displayed</EM> values for the <EM>ACS</EM><STRONG>_</STRONG> and <EM>WACS</EM><STRONG>_</STRONG> constants depend on
+
+ <STRONG>o</STRONG> the library configuration, i.e., <STRONG>ncurses</STRONG> versus <STRONG>ncursesw</STRONG>, where the
+ latter is capable of displaying Unicode while the former is not,
+ and
+
+ <STRONG>o</STRONG> whether the <EM>locale</EM> uses UTF-8 encoding.