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.
+ putchar in stdio(3). If the advance is at the right mar-
+ gin:
+
+ 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 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 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
+ can be copied from one place to another using inch(3x) 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
+ 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.
+ replacement for it, or if the terminal and locale configu-
+ ration requires Unicode but the library is unable to use
+ Unicode.
+
+ The names are taken from VT100 nomenclature.
NameDefaultDescription
--------------------------------------------------
@@ -151,26 +172,32 @@
ACS_VLINE | vertical line
-
All routines return the integer ERR upon failure and OK on
- success (the SVr4 manuals specify only "an integer value
+ success (the SVr4 manuals specify only "an integer value
other than ERR") upon successful completion, unless other-
wise noted in the preceding routine descriptions.
+ 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.
-
-
NOTES
- Note that addch, mvaddch, mvwaddch, and echochar may be
+
+
+ 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.
+ 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 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
@@ -180,18 +207,31 @@
The ACS-prefixed names for them were invented for
ncurses(3x).
- The TABSIZE variable is implemented in some versions of
+ The displayed values for the ACS_ and WACS_ constants
+ depend on
+
+ o the library configuration, i.e., ncurses versus ncurs-
+ esw, 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 discus-
+ sion of NCURSES_NO_UTF8_ACS in ncurses(3x)).
+
+ The TABSIZE variable is implemented in some versions of
curses, but is not part of X/Open curses.
- If ch is a carriage return, the cursor is moved to the
- beginning of the current row of the window. This is true
+ 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.
-