curs_addch(3X)curs_addch(3X)NAME
addch, waddch, mvaddch, mvwaddch, echochar, wechochar - add a character
(with attributes) to a curses window, then advance the cursor
SYNOPSIS
#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);
DESCRIPTION
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 margin, 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 appropri‐
ately within the window. Backspace moves the cursor 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 considered 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 char‐
acter 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 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, or a call to waddch followed by a call
to wrefresh. The knowledge that only a single character is being out‐
put is used and, for non-control characters, a considerable performance
gain may be seen by using these routines instead of their equivalents.
Line Graphics
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. The names are taken from VT100 nomencla‐
ture.
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
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 suc‐
cessful 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.
NOTES
Note that addch, mvaddch, mvwaddch, and echochar may be macros.
PORTABILITY
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 analo‐
gous 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.
SEE ALSOcurses(3X), curs_attr(3X), curs_clear(3X), curs_inch(3X), curs_out‐
opts(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)
