- 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 in stdio(3). If the advance is at the right mar-
- gin, the cursor automatically wraps to the beginning of
- the next line. At the bottom of the current scrolling
- region, if scrollok is enabled, the scrolling region is
- scrolled up one line.
-
- If ch is a tab, newline, or backspace, the cursor is moved
- appropriately within the window. Backspace moves the cur-
- sor one character left; at the left edge of a window it
- does nothing. 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. Tabs are con-
- sidered to be at every eighth column. The tab interval
- may be altered by setting the TABSIZE variable.
-
- If ch is any control character other than tab, newline, or
- backspace, it is drawn in ^X notation. Calling winch
- after adding a control character does not return the char-
- acter itself, but instead returns the ^-representation of
- the control character.
-
- Video attributes can be combined with a character argument
- passed to 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 and
- addch.) See the curs_attr(3x) page for values of prede-
- fined 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, 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
+
+
+ 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
+ advance is at the right margin:
+
+ 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
+ enabled, the scrolling region is scrolled up one line.
+
+ 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
+ moved appropriately within the window:
+
+ 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
+ current line.
+
+ 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.
+
+ 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.
+ (Thus, text, including attributes, can be copied from one place to
+ 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
+ performance gain may be seen by using these routines instead of their
equivalents.
- LineGraphics
- The following variables may be used to add line drawing
- characters to the screen with routines of the addch fam-
- ily. The default character listed below is used if the
- acsc capability does not define a terminal-specific
- replacement for it. The names are taken from VT100 nomen-
- clature.
-
- NameDefaultDescription
- --------------------------------------------------
- ACS_BLOCK # solid square block
- ACS_BOARD # board of squares
- ACS_BTEE + bottom tee
- ACS_BULLET o bullet
- ACS_CKBOARD : checker board (stipple)
- ACS_DARROW v arrow pointing down
- ACS_DEGREE ' degree symbol
- ACS_DIAMOND + diamond
- ACS_GEQUAL > greater-than-or-equal-to
- ACS_HLINE - horizontal line
- ACS_LANTERN # lantern symbol
- ACS_LARROW < arrow pointing left
- ACS_LEQUAL < less-than-or-equal-to
- ACS_LLCORNER + lower left-hand corner
- ACS_LRCORNER + lower right-hand corner
- ACS_LTEE + left tee
- ACS_NEQUAL ! not-equal
- ACS_PI * greek pi
- ACS_PLMINUS # plus/minus
- ACS_PLUS + plus
- ACS_RARROW > arrow pointing right
- ACS_RTEE + right tee
- ACS_S1 - scan line 1
- ACS_S3 - scan line 3
- ACS_S7 - scan line 7
- ACS_S9 _ scan line 9
- ACS_STERLING f pound-sterling symbol
- ACS_TTEE + top tee
- ACS_UARROW ^ arrow pointing up
- ACS_ULCORNER + upper left-hand corner
- ACS_URCORNER + upper right-hand corner
- ACS_VLINE | vertical line
+
+ 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
+ configuration requires Unicode but the library is unable to use
+ Unicode.
-
-
RETURN VALUE
- 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 other-
- wise noted in the preceding routine descriptions.
+ The names are taken from VT100 nomenclature.
- Functions with a "mv" prefix first perform a cursor move-
- ment using wmove, and return an error if the position is
- outside the window, or if the window pointer is null.
+ ACSACSacscGlyph
+ NameDefaultcharName
+ ---------------------------------------------------------
+ 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
-
-
NOTES
- Note that addch, mvaddch, mvwaddch, and echochar may be
- macros.
+
+ 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
+ the window pointer is null.
-
-
PORTABILITY
- All these functions are described in the XSI Curses stan-
- dard, Issue 4. The defaults specified for forms-drawing
- characters apply in the POSIX locale.
+ If it is not possible to add a complete character, an error is
+ returned:
- 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 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).
+ 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
- The TABSIZE variable is implemented in some versions of
- curses, but is not part of X/Open curses.
+ 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.
- 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.
+
+ All these functions are described in the XSI Curses standard, Issue 4.
+ The defaults specified for forms-drawing characters apply in the POSIX
+ locale.
+
+
+
+ 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
+ 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 displayed values for the ACS_ and WACS_ constants depend on
+
+ 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.
+
+ 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
+ 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-
+ 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 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
+ 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),
+ ncurses discards the partially built character, starting over again.
+
+ 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 call wadd_wch for characters which cannot be handled by waddch.
+
+
+
+ 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
+ is not documented.
+
+
+