curs_addch(3x) curs_addch(3x)
addch, waddch, mvaddch, mvwaddch, echochar, wechochar -
add a character (with attributes) to a curses window, then
advance the cursor
#include <curses.h>
int addch(const chtype ch);
int waddch(WINDOW *win, const chtype ch);
int mvaddch(int y, int x, const chtype ch);
int mvwaddch(WINDOW *win, int y, int x, const chtype ch);
int echochar(const chtype ch);
int wechochar(WINDOW *win, const chtype 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 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
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
equivalents.
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.
Name Default Description
--------------------------------------------------
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
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.
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.
Note that addch, mvaddch, mvwaddch, and echochar may be
macros.
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
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 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
of other implementations, but is not documented.
curses(3x), curs_attr(3x), curs_clear(3x), curs_inch(3x),
curs_outopts(3x), curs_refresh(3x), curs_variables(3x),
putc(3).
Comparable functions in the wide-character (ncursesw)
library are described in curs_add_wch(3x).
curs_addch(3x)