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-<H1 class="no-header">curs_addch 3x</H1>
+<H1 class="no-header">curs_addch 3x 2024-04-20 ncurses 6.4 Library calls</H1>
<PRE>
-<STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
<STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
+<STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
Library calls <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
</PRE><H2><a name="h2-NAME">NAME</a></H2><PRE>
- <STRONG>addch</STRONG>, <STRONG>waddch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, <STRONG>echochar</STRONG>, <STRONG>wechochar</STRONG> - add a character
- (with attributes) to a <STRONG>curses</STRONG> window, then advance the cursor
+ <STRONG>addch</STRONG>, <STRONG>waddch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, <STRONG>echochar</STRONG>, <STRONG>wechochar</STRONG> - add a <EM>curses</EM>
+ character to a window and advance the cursor
</PRE><H2><a name="h2-SYNOPSIS">SYNOPSIS</a></H2><PRE>
<STRONG>#include</STRONG> <STRONG><curses.h></STRONG>
- <STRONG>int</STRONG> <STRONG>addch(const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
- <STRONG>int</STRONG> <STRONG>waddch(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
- <STRONG>int</STRONG> <STRONG>mvaddch(int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
- <STRONG>int</STRONG> <STRONG>mvwaddch(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>int</STRONG> <STRONG>y,</STRONG> <STRONG>int</STRONG> <STRONG>x,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
- <STRONG>int</STRONG> <STRONG>echochar(const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
- <STRONG>int</STRONG> <STRONG>wechochar(WINDOW</STRONG> <STRONG>*win,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <STRONG>ch);</STRONG>
+ <STRONG>int</STRONG> <STRONG>addch(const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>waddch(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>mvaddch(int</STRONG> <EM>y</EM><STRONG>,</STRONG> <STRONG>int</STRONG> <EM>x</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>mvwaddch(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>const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
+
+ <STRONG>int</STRONG> <STRONG>echochar(const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
+ <STRONG>int</STRONG> <STRONG>wechochar(WINDOW</STRONG> <STRONG>*</STRONG><EM>win</EM><STRONG>,</STRONG> <STRONG>const</STRONG> <STRONG>chtype</STRONG> <EM>ch</EM><STRONG>);</STRONG>
</PRE><H2><a name="h2-DESCRIPTION">DESCRIPTION</a></H2><PRE>
-</PRE><H3><a name="h3-Adding-characters">Adding characters</a></H3><PRE>
- The <STRONG>addch</STRONG>, <STRONG>waddch</STRONG>, <STRONG>mvaddch</STRONG> and <STRONG>mvwaddch</STRONG> routines put the character <EM>ch</EM>
- into the given window at its current window position, which is then
- advanced. They are analogous to <STRONG>putchar(3)</STRONG> in <STRONG>stdio(3)</STRONG>. If the
- advance is at the right margin:
-
- <STRONG>o</STRONG> The cursor automatically wraps to the beginning of the next line.
-
- <STRONG>o</STRONG> At the bottom of the current scrolling region, and if <STRONG>scrollok</STRONG> is
- enabled, the scrolling region is scrolled up one line.
-
- <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
-
- If <EM>ch</EM> is a tab, newline, carriage return or backspace, the cursor is
- moved appropriately within the window:
-
- <STRONG>o</STRONG> Backspace moves the cursor one character left; at the left edge of
- a window it does nothing.
-
- <STRONG>o</STRONG> Carriage return moves the cursor to the window left margin on the
- current line.
-
- <STRONG>o</STRONG> Newline does a <STRONG>clrtoeol</STRONG>, then moves the cursor to the window left
- margin on the next line, scrolling the window if on the last line.
-
- <STRONG>o</STRONG> Tabs are considered to be at every eighth column. The tab interval
- may be altered by setting the <STRONG>TABSIZE</STRONG> variable.
-
- If <EM>ch</EM> is any other control character, it is drawn in <STRONG>^</STRONG><EM>X</EM> notation.
- Calling <STRONG>winch</STRONG> after adding a control character does not return the
- character itself, but instead returns the ^-representation of the con-
- trol character.
-
- Video attributes can be combined with a character argument passed to
- <STRONG>addch</STRONG> or related functions by logical-ORing them into the character.
- (Thus, text, including attributes, can be copied from one place to
- another using <STRONG><A HREF="curs_inch.3x.html">inch(3x)</A></STRONG> and <STRONG>addch</STRONG>.) See the <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG> page for val-
- ues of predefined video attribute constants that can be usefully OR'ed
- into characters.
-
-
-</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><H3><a name="h3-Adding-Characters">Adding Characters</a></H3><PRE>
+ <STRONG>waddch</STRONG> puts the character <EM>ch</EM> at the cursor position of window <EM>win</EM>, then
+ advances the cursor position, analogously to the standard C library's
+ <STRONG>putchar(3)</STRONG>. <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG> describes the variants of this function.
+
+ If advancement occurs at the right margin,
+
+ <STRONG>o</STRONG> the cursor automatically wraps to the beginning of the next line;
+ and
+
+ <STRONG>o</STRONG> at the bottom of the current scrolling region, and if <STRONG><A HREF="scrollok.3x.html">scrollok(3x)</A></STRONG>
+ is enabled for <EM>win</EM>, the scrolling region scrolls up one line.
+
+ If <EM>ch</EM> is a backspace, carriage return, line feed, or tab, the cursor
+ moves appropriately within the window.
+
+ <STRONG>o</STRONG> Backspace moves the cursor one character left; at the left margin
+ of a window, it does nothing.
+
+ <STRONG>o</STRONG> Carriage return moves the cursor to the left margin on the current
+ line of the window.
+
+ <STRONG>o</STRONG> Line feed does a <STRONG><A HREF="curs_clear.3x.html">clrtoeol(3x)</A></STRONG>, then moves the cursor to the left
+ margin on the next line of the window, and if <STRONG><A HREF="scrollok.3x.html">scrollok(3x)</A></STRONG> is
+ enabled for <EM>win</EM>, scrolls the window if the cursor was already on
+ the last line.
+
+ <STRONG>o</STRONG> Tab advances the cursor to the next tab stop (possibly on the next
+ line); these are placed at every eighth column by default. Alter
+ the tab interval with the <STRONG>TABSIZE</STRONG> extension; see
+ <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>.
+
+ If <EM>ch</EM> is any other nonprintable character, it is drawn in printable
+ form, using the same convention as <STRONG><A HREF="unctrl.3x.html">unctrl(3x)</A></STRONG>.
+
+ Calling <STRONG><A HREF="curs_inch.3x.html">winch(3x)</A></STRONG> on the location of a nonprintable character does not
+ return the character itself, but its <STRONG><A HREF="unctrl.3x.html">unctrl(3x)</A></STRONG> representation.
+
+ <EM>ch</EM> may contain rendering and/or color attributes, and others can be
+ combined with the parameter by logically "or"ing with it. (A character
+ with its attributes can be copied from place to place using <STRONG><A HREF="curs_inch.3x.html">winch(3x)</A></STRONG>
+ and <STRONG>waddch</STRONG>.) See <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG> for values of predefined video
+ attribute constants that can be usefully "or"ed with characters.
+
+
+</PRE><H3><a name="h3-Echoing-Characters">Echoing Characters</a></H3><PRE>
+ <STRONG>echochar</STRONG> and <STRONG>wechochar</STRONG> are equivalent to calling (<STRONG>w</STRONG>)<STRONG>addch</STRONG> followed by
+ (<STRONG>w</STRONG>)<STRONG>refresh</STRONG>. <EM>curses</EM> interprets these functions as a hint that only a
+ single character is being output; for non-control characters, a
+ considerable performance gain may be enjoyed by employing them.
+
+
+</PRE><H3><a name="h3-Forms-Drawing-Characters">Forms-Drawing Characters</a></H3><PRE>
+ <EM>curses</EM> defines macros starting with <STRONG>ACS_</STRONG> that can be used with <STRONG>waddch</STRONG>
+ to write line-drawing and other special characters to the screen.
+ <EM>ncurses</EM> terms these <EM>forms-drawing</EM> <EM>characters.</EM> The ACS default listed
+ below is used if the <STRONG>acs_chars</STRONG> (<STRONG>acsc</STRONG>) <EM>terminfo</EM> capability does not
+ define a terminal-specific replacement for it, or if the terminal and
+ locale configuration requires Unicode to access these characters but
+ the library is unable to use Unicode. The "acsc char" column
+ corresponds to how the characters are specified in the <STRONG>acs_chars</STRONG> string
+ capability, and the characters in it may appear on the screen if the
+ terminal's database entry incorrectly advertises ACS support. The name
+ "ACS" originates in the Alternate Character Set feature of the DEC
+ VT100 terminal.
+
+ <STRONG>ACS</STRONG> <STRONG>acsc</STRONG>
+ <STRONG>Symbol</STRONG> <STRONG>Default</STRONG> <STRONG>char</STRONG> <STRONG>Glyph</STRONG> <STRONG>Name</STRONG>
+ ------------------------------------------------------------------------
+ <STRONG>ACS_BLOCK</STRONG> # 0 solid square block
+ <STRONG>ACS_BOARD</STRONG> # h board of squares
+ <STRONG>ACS_BTEE</STRONG> + v bottom tee
+ <STRONG>ACS_BULLET</STRONG> o ~ bullet
+ <STRONG>ACS_CKBOARD</STRONG> : a checker board (stipple)
+ <STRONG>ACS_DARROW</STRONG> v . arrow pointing down
+ <STRONG>ACS_DEGREE</STRONG> ' f degree symbol
+ <STRONG>ACS_DIAMOND</STRONG> + ` diamond
+ <STRONG>ACS_GEQUAL</STRONG> > > greater-than-or-equal-to
+ <STRONG>ACS_HLINE</STRONG> - q horizontal line
+ <STRONG>ACS_LANTERN</STRONG> # i lantern symbol
+ <STRONG>ACS_LARROW</STRONG> < , arrow pointing left
+ <STRONG>ACS_LEQUAL</STRONG> < y less-than-or-equal-to
+ <STRONG>ACS_LLCORNER</STRONG> + m lower left-hand corner
+ <STRONG>ACS_LRCORNER</STRONG> + j lower right-hand corner
+ <STRONG>ACS_LTEE</STRONG> + t left tee
+ <STRONG>ACS_NEQUAL</STRONG> ! | not-equal
+ <STRONG>ACS_PI</STRONG> * { greek pi
+ <STRONG>ACS_PLMINUS</STRONG> # g plus/minus
+ <STRONG>ACS_PLUS</STRONG> + n plus
+ <STRONG>ACS_RARROW</STRONG> > + arrow pointing right
+ <STRONG>ACS_RTEE</STRONG> + u right tee
+ <STRONG>ACS_S1</STRONG> - o scan line 1
+ <STRONG>ACS_S3</STRONG> - p scan line 3
+ <STRONG>ACS_S7</STRONG> - r scan line 7
+ <STRONG>ACS_S9</STRONG> _ s scan line 9
+ <STRONG>ACS_STERLING</STRONG> f } pound-sterling symbol
+ <STRONG>ACS_TTEE</STRONG> + w top tee
+ <STRONG>ACS_UARROW</STRONG> ^ - arrow pointing up
+ <STRONG>ACS_ULCORNER</STRONG> + l upper left-hand corner
+ <STRONG>ACS_URCORNER</STRONG> + k upper right-hand corner
+ <STRONG>ACS_VLINE</STRONG> | 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.
+ These functions return <STRONG>OK</STRONG> on success and <STRONG>ERR</STRONG> on failure.
+
+ In <EM>ncurses</EM>, <STRONG>waddch</STRONG> returns <STRONG>ERR</STRONG> if it is not possible to add a complete
+ character at the cursor position, as when conversion of a multibyte
+ character to a byte sequence fails, or at least one of the resulting
+ bytes cannot be added to the window. See section "PORTABILITY" below
+ regarding the use of <STRONG>waddch</STRONG> with multibyte characters.
- 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.
+ <STRONG>waddch</STRONG> can successfully write a character at the bottom right location
+ of the window. However, <EM>ncurses</EM> returns <STRONG>ERR</STRONG> if <STRONG><A HREF="scrollok.3x.html">scrollok(3x)</A></STRONG> is not
+ enabled in that event, because it is not possible to wrap to a new
+ line.
+
+ 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>
- Note that <STRONG>addch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, and <STRONG>echochar</STRONG> may be macros.
+ <STRONG>addch</STRONG>, <STRONG>mvaddch</STRONG>, <STRONG>mvwaddch</STRONG>, and <STRONG>echochar</STRONG> may be implemented as 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
+ X/Open Curses, Issue 4 describes these functions. It specifies no
+ error conditions for them.
+
+ SVr4 <EM>curses</EM> describes a successful return value only as "an integer
+ value other than <STRONG>ERR</STRONG>".
+
+ 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.
+ X/Open Curses states that the <STRONG>ACS_</STRONG> definitions are <EM>char</EM> constants.
- 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>.
+ Some implementations are problematic.
- The <EM>displayed</EM> values for the <EM>ACS</EM><STRONG>_</STRONG> and <EM>WACS</EM><STRONG>_</STRONG> constants depend on
+ <STRONG>o</STRONG> Solaris <EM>curses</EM>, for example, define the ACS symbols as constants;
+ others define them as elements of an array.
- <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
+ This implementation uses an array, <STRONG>acs_map</STRONG>, as did SVr4 <EM>curses</EM>.
+ NetBSD also uses an array, actually named <STRONG>_acs_char</STRONG>, with a <STRONG>#define</STRONG>
+ for compatibility.
+
+ <STRONG>o</STRONG> HP-UX <EM>curses</EM> equates some of the <STRONG>ACS_</STRONG> symbols to the analogous
+ <STRONG>WACS_</STRONG> symbols as if the <STRONG>ACS_</STRONG> symbols were wide characters (see
+ <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>). The misdefined symbols are the arrows and
+ others that are not used for line drawing.
+
+ <STRONG>o</STRONG> X/Open Curses (Issues 2 through 7) has a typographical error for
+ the <STRONG>ACS_LANTERN</STRONG> symbol, equating its "VT100+ Character" to "I"
+ (capital I), while the header files for SVr4 <EM>curses</EM> and other
+ implementations use "i" (small i).
+
+ None of the terminal descriptions on Unix platforms use uppercase
+ I, except for Solaris (in its <EM>terminfo</EM> entry for <STRONG>screen(1)</STRONG>,
+ apparently based on the X/Open documentation around 1995). On the
+ other hand, its <STRONG>gs6300</STRONG> (AT&T PC6300 with EMOTS Terminal Emulator)
+ description uses lowercase i.
- <STRONG>o</STRONG> whether the <EM>locale</EM> uses UTF-8 encoding.
+ Some ACS symbols (<STRONG>ACS_S3</STRONG>, <STRONG>ACS_S7</STRONG>, <STRONG>ACS_LEQUAL</STRONG>, <STRONG>ACS_GEQUAL</STRONG>, <STRONG>ACS_PI</STRONG>,
+ <STRONG>ACS_NEQUAL</STRONG>, and <STRONG>ACS_STERLING</STRONG>) were not documented in any publicly
+ released System V. However, many publicly available <EM>terminfo</EM> entries
+ include <STRONG>acsc</STRONG> strings in which their key characters <STRONG>(</STRONG>pryz{|}<STRONG>)</STRONG> are
+ embedded, and a second-hand list of their character descriptions has
+ come to light. The <EM>ncurses</EM> developers invented ACS-prefixed names for
+ them.
- In certain cases, the terminal is unable to display line-drawing char-
- 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 <EM>displayed</EM> values of <STRONG>ACS_</STRONG> constants depend on
+
+ <STRONG>o</STRONG> the <EM>ncurses</EM> ABI--for example, wide-character versus non-wide-
+ character configurations (the former is capable of displaying
+ Unicode while the latter is not), and
+
+ <STRONG>o</STRONG> whether the locale uses UTF-8 encoding.
+
+ In certain cases, the terminal is unable to display forms-drawing
+ characters <EM>except</EM> by using UTF-8; see the discussion of the
+ <EM>NCURSES</EM><STRONG>_</STRONG><EM>NO</EM><STRONG>_</STRONG><EM>UTF8</EM><STRONG>_</STRONG><EM>ACS</EM> environment variable in <STRONG><A HREF="ncurses.3x.html">ncurses(3x)</A></STRONG>).
</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.
+ 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 wide in an SVr3 or SVr4 implementation,
+ but in the X/Open Curses model, the details are not given. The
+ important distinction between SVr4 <EM>curses</EM> and X/Open Curses is that the
+ latter separates non-character information (attributes and color) from
+ the character code, which SVr4 packs into a <EM>chtype</EM> for passage to
+ <STRONG>waddch</STRONG>.
+
+ In <EM>ncurses</EM>, <EM>chtype</EM> holds an eight-bit character. But the library
+ allows a multibyte character to be passed in a succession of calls to
+ <STRONG>waddch</STRONG>. Other implementations do not; a <STRONG>waddch</STRONG> call transmits exactly
+ one character, which may be rendered in one or more screen locations
+ depending on whether it is printable.
+
+ Depending on the locale settings, <EM>ncurses</EM> inspects the byte passed in
+ each <STRONG>waddch</STRONG> call, and checks whether the latest call continues a
+ multibyte sequence. When a character is <EM>complete</EM>, <EM>ncurses</EM> displays the
+ character and advances the cursor.
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.
+ multibyte character sequence by changing the current location--for
+ example, with <STRONG><A HREF="curs_move.3x.html">wmove(3x)</A></STRONG>--<EM>ncurses</EM> discards the incomplete character.
- For portability to other implementations, do not rely upon this behav-
- ior:
+ For portability to other implementations, do not rely upon this
+ behavior. Check whether a character can be represented as a single
+ byte in the current locale.
- <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> If it can, call either <STRONG>waddch</STRONG> or <STRONG><A HREF="curs_add_wch.3x.html">wadd_wch(3x)</A></STRONG>.
- <STRONG>o</STRONG> call <STRONG>wadd_wch</STRONG> for characters which cannot be handled by <STRONG>waddch</STRONG>.
+ <STRONG>o</STRONG> If it cannot, use only <STRONG><A HREF="curs_add_wch.3x.html">wadd_wch(3x)</A></STRONG>.
</PRE><H3><a name="h3-TABSIZE">TABSIZE</a></H3><PRE>
- The <STRONG>TABSIZE</STRONG> variable is implemented in some versions of curses, but is
- not part of X/Open curses.
-
- 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
- is not documented.
+ SVr4 and other versions of <EM>curses</EM> implement the <STRONG>TABSIZE</STRONG> variable, but
+ X/Open Curses does not specify it (see <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>).
</PRE><H2><a name="h2-SEE-ALSO">SEE ALSO</a></H2><PRE>
- <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>, <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>, <STRONG><A HREF="curs_inch.3x.html">curs_inch(3x)</A></STRONG>, <STRONG>curs_out-</STRONG>
- <STRONG><A HREF="curs_outopts.3x.html">opts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>, <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>putc(3)</STRONG>.
+ <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG> describes comparable functions of the <EM>ncurses</EM> library
+ in its wide-character configuration (<EM>ncursesw</EM>).
- Comparable functions in the wide-character (ncursesw) library are
- described in <STRONG><A HREF="curs_add_wch.3x.html">curs_add_wch(3x)</A></STRONG>.
+ <STRONG><A HREF="ncurses.3x.html">curses(3x)</A></STRONG>, <STRONG><A HREF="curs_addchstr.3x.html">curs_addchstr(3x)</A></STRONG>, <STRONG><A HREF="curs_addstr.3x.html">curs_addstr(3x)</A></STRONG>, <STRONG><A HREF="curs_attr.3x.html">curs_attr(3x)</A></STRONG>,
+ <STRONG><A HREF="curs_clear.3x.html">curs_clear(3x)</A></STRONG>, <STRONG><A HREF="curs_inch.3x.html">curs_inch(3x)</A></STRONG>, <STRONG><A HREF="curs_outopts.3x.html">curs_outopts(3x)</A></STRONG>, <STRONG><A HREF="curs_refresh.3x.html">curs_refresh(3x)</A></STRONG>,
+ <STRONG><A HREF="curs_variables.3x.html">curs_variables(3x)</A></STRONG>, <STRONG>putchar(3)</STRONG>
-
<STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
+
ncurses 6.4 2024-04-20 <STRONG><A HREF="curs_addch.3x.html">curs_addch(3x)</A></STRONG>
</PRE>
<div class="nav">
<ul>
<li><a href="#h2-SYNOPSIS">SYNOPSIS</a></li>
<li><a href="#h2-DESCRIPTION">DESCRIPTION</a>
<ul>
-<li><a href="#h3-Adding-characters">Adding characters</a></li>
-<li><a href="#h3-Echoing-characters">Echoing characters</a></li>
-<li><a href="#h3-Line-Graphics">Line Graphics</a></li>
+<li><a href="#h3-Adding-Characters">Adding Characters</a></li>
+<li><a href="#h3-Echoing-Characters">Echoing Characters</a></li>
+<li><a href="#h3-Forms-Drawing-Characters">Forms-Drawing Characters</a></li>
</ul>
</li>
<li><a href="#h2-RETURN-VALUE">RETURN VALUE</a></li>
projects / ncurses.git / blobdiff