- addch, waddch, mvaddch, mvwaddch, echochar, wechochar - add a character
- (with attributes) to a curses window, then advance the cursor
+ addch, waddch, mvaddch, mvwaddch, echochar, wechochar - add a character
+ (with attributes) to a curses window, then advance the cursor
- The addch, waddch, mvaddch and mvwaddch routines put the character ch
+ The addch, waddch, mvaddch and mvwaddch routines put the character ch
into the given window at its current window position, which is then
- advanced. They are analogous to putchar(3) in stdio(3). If the
+ advanced. They are analogous to putchar(3) in stdio(3). If the
advance is at the right margin:
- o The cursor automatically wraps to the beginning of the next line.
+ o The cursor automatically wraps to the beginning of the next line.
- o At the bottom of the current scrolling region, and if scrollok is
+ o At the bottom of the current scrolling region, and if scrollok is
enabled, the scrolling region is scrolled up one line.
- o If scrollok is not enabled, writing a character at the lower right
+ o If scrollok 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 ch is a tab, newline, carriage return or backspace, the cursor is
+ If ch is a tab, newline, carriage return or backspace, the cursor is
moved appropriately within the window:
- o Backspace moves the cursor one character left; at the left edge of
+ o Backspace moves the cursor one character left; at the left edge of
a window it does nothing.
- o Carriage return moves the cursor to the window left margin on the
+ o Carriage return moves the cursor to the window left margin on the
current line.
- o Newline does a clrtoeol, then moves the cursor to the window left
+ o Newline does a clrtoeol, then moves the cursor to the window left
margin on the next line, scrolling the window if on the last line.
- o Tabs are considered to be at every eighth column. The tab interval
- may be altered by setting the TABSIZE variable.
+ o Tabs are considered to be at every eighth column. The tab interval
+ may be altered by setting the TABSIZE variable.
- If ch is any other control character, it is drawn in ^X notation.
- Calling winch after adding a control character does not return the
- character itself, but instead returns the ^-representation of the con-
- trol character.
+ If ch is any other nonprintable character, it is drawn in printable
+ form, i.e., the ^X notation used by unctrl(3X). Calling winch after
+ adding a nonprintable character does not return the character itself,
+ but instead returns the printable representation of the character.
Video attributes can be combined with a character argument passed to
- addch or related functions by logical-ORing them into the character.
+ addch or related functions by logical-ORing them into the character.
(Thus, text, including attributes, can be copied from one place to
- another using inch(3x) and addch.) See the curs_attr(3x) page for val-
- ues of predefined video attribute constants that can be usefully OR'ed
- into characters.
+ another using inch(3X) and addch.) See the curs_attr(3X) page for
+ values of predefined video attribute constants that can be usefully
+ OR'ed into characters.
- The echochar and wechochar routines are equivalent to a call to addch
- followed by a call to refresh(3x), or a call to waddch followed by a
- call to wrefresh. 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.
+ The echochar and wechochar routines are equivalent to a call to addch
+ followed by a call to refresh(3X), or a call to waddch followed by a
+ call to wrefresh. The knowledge that only a single character is being
+ output is used and, for non-control characters, a considerable
+ performance gain may be seen by using these routines instead of their
+ equivalents.
The following variables may be used to add line drawing characters to
- the screen with routines of the addch family. The default character
- listed below is used if the acsc 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 screen with routines of the addch family. The default character
+ listed below is used if the acsc capability does not define a terminal-
+ specific replacement for it, or if the terminal and locale
+ configuration requires Unicode but the library is unable to use
+ Unicode.
The names are taken from VT100 nomenclature.
- ACSACSacscGlyph
- NameDefaultcharName
+ ACSACSacscGlyph
+ NameDefaultcharName
---------------------------------------------------------
ACS_BLOCK # 0 solid square block
ACS_BOARD # h board of squares
@@ -163,18 +166,29 @@
- All routines return the integer ERR upon failure and OK on success (the
- SVr4 manuals specify only "an integer value other than ERR") upon suc-
- cessful completion, unless otherwise noted in the preceding routine
+ All routines return the integer ERR upon failure and OK on success (the
+ SVr4 manuals specify only "an integer value other than ERR") upon
+ successful completion, unless otherwise noted in the preceding routine
descriptions.
- Functions with a "mv" prefix first perform a cursor movement using
- wmove, and return an error if the position is outside the window, or if
+ Functions with a "mv" prefix first perform a cursor movement using
+ wmove, 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:
+
+ o If scrollok 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
+
+ o 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.
+
- X/Open Curses states that the ACS_ definitions are char constants. For
- the wide-character implementation (see curs_add_wch), there are analo-
- gous WACS_ definitions which are cchar_t constants.
+ X/Open Curses states that the ACS_ definitions are char constants. For
+ the wide-character implementation (see curs_add_wch), there are
+ analogous WACS_ definitions which are cchar_t constants. Some
+ implementations are problematic:
+
+ o 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 acs_map, as done in SVr4 curses.
+ NetBSD also uses an array, actually named _acs_char, with a #define
+ for compatibility.
+
+ o HPUX curses equates some of the ACS_ symbols to the analogous WACS_
+ symbols as if the ACS_ symbols were wide characters. The
+ misdefined symbols are the arrows and other symbols which are not
+ used for line-drawing.
+
+ o X/Open Curses (issues 2 through 7) has a typographical error for
+ the ACS_LANTERN symbol, equating its "VT100+ Character" to I
+ (capital I), while the header files for SVr4 curses and the various
+ implementations use i (lowercase).
+
+ None of the terminal descriptions on Unix platforms use uppercase-
+ I, except for Solaris (i.e., screen's terminal description,
+ apparently based on the X/Open documentation around 1995). On the
+ other hand, the terminal description gs6300 (AT&T PC6300 with EMOTS
+ Terminal 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 acsc
+ System V. However, many publicly available terminfos include acsc
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 ncurses(3x).
+ The ACS-prefixed names for them were invented for ncurses(3X).
- The displayed values for the ACS_ and WACS_ constants depend on
+ The displayed values for the ACS_ and WACS_ constants depend on
- o the library configuration, i.e., ncurses versus ncursesw, where the
+ o the library configuration, i.e., ncurses versus ncursesw, where the
latter is capable of displaying Unicode while the former is not,
and
- o whether the locale uses UTF-8 encoding.
+ o whether the locale uses UTF-8 encoding.
- In certain cases, the terminal is unable to display line-drawing char-
- acters except by using UTF-8 (see the discussion of NCURSES_NO_UTF8_ACS
- in ncurses(3x)).
+ In certain cases, the terminal is unable to display line-drawing
+ characters except by using UTF-8 (see the discussion of
+ NCURSES_NO_UTF8_ACS in ncurses(3X)).
- X/Open Curses assumes that the parameter passed to waddch contains a
- single character. As discussed in curs_attr(3x), that character may
+ X/Open Curses assumes that the parameter passed to waddch contains a
+ single character. As discussed in curs_attr(3X), 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 chtype to pass to waddch.
+ distinction between SVr4 curses and X/Open Curses is that the non-
+ character information (attributes and color) was separated from the
+ character information which is packed in a chtype to pass to waddch.
- In this implementation, chtype holds eight bits. But ncurses allows
- multibyte characters to be passed in a succession of calls to waddch.
- The other implementations do not do this; a call to waddch 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, chtype holds an eight-bit character. But
+ ncurses allows multibyte characters to be passed in a succession of
+ calls to waddch. The other implementations do not do this; a call to
+ waddch 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 waddch, and check if the latest call will continue a
- multibyte sequence. When a character is complete, ncurses displays the
+ in each call to waddch, and check if the latest call will continue a
+ multibyte sequence. When a character is complete, 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 wmove),
+ multibyte character by moving the current location (e.g., using wmove),
ncurses discards the partially built character, starting over again.
- For portability to other implementations, do not rely upon this behav-
- ior:
+ For portability to other implementations, do not rely upon this
+ behavior:
- o check if a character can be represented as a single byte in the
- current locale before attempting call waddch, and
+ o check if a character can be represented as a single byte in the
+ current locale before attempting call waddch, and
- o call wadd_wch for characters which cannot be handled by waddch.
+ o call wadd_wch for characters which cannot be handled by waddch.
- The TABSIZE variable is implemented in some versions of curses, but is
- not part of X/Open curses.
+ The TABSIZE variable is implemented in SVr4 and other versions of
+ curses, but is not part of X/Open curses (see curs_variables(3X) for
+ more details).
- If ch 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
+ If ch 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.