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(chtype ch);
int waddch(WINDOW *win, chtype ch);
int mvaddch(int y, int x, chtype ch);
int mvwaddch(WINDOW *win, int y, int x, chtype ch);
int echochar(chtype ch);
int wechochar(WINDOW *win, 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.
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. (To emit control characters
literally, use echochar.)
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 doesn't define a terminal-
specific replacement for it (but see the EXTENSIONS section below).
The names are taken from VT100 nomenclature.
Name Default Description
──────────────────────────────────────────────────
ACS_ULCORNER + upper left-hand corner
ACS_LLCORNER + lower left-hand corner
ACS_URCORNER + upper right-hand corner
ACS_LRCORNER + lower right-hand corner
ACS_RTEE + right tee
ACS_LTEE + left tee
ACS_BTEE + bottom tee
ACS_TTEE + top tee
ACS_HLINE - horizontal line
ACS_VLINE | vertical line
ACS_PLUS + plus
ACS_S1 - scan line 1
ACS_S9 _ scan line 9
ACS_DIAMOND + diamond
ACS_CKBOARD : checker board (stipple)
ACS_DEGREE ' degree symbol
ACS_PLMINUS # plus/minus
ACS_BULLET o bullet
ACS_LARROW < arrow pointing left
ACS_RARROW > arrow pointing right
ACS_DARROW v arrow pointing down
ACS_UARROW ^ arrow pointing up
ACS_BOARD # board of squares
ACS_LANTERN # lantern symbol
ACS_BLOCK # solid square block
ACS_S3 - scan line 3
ACS_S7 - scan line 7
ACS_LEQUAL < less-than-or-equal-to
ACS_GEQUAL > greater-than-or-equal-to
ACS_PI * greek pi
ACS_NEQUAL ! not-equal
ACS_STERLING f pound-sterling symbol
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.
NOTES
Note that addch, mvaddch, mvwaddch, and echochar may be macros.
EXTENSIONS
The following extended curses features are available only on PC-clone
consoles and compatible terminals obeying the ANSI.SYS de-facto stan‐
dard for terminal control sequences. They are not part of XSI curses.
The attribute A_ALTCHARSET actually forces literal display of PC ROM
characters including the high-half graphics. Your console driver may
still capture or translate a few (such as ESC) but this feature should
give you access to the card-suit characters, up and down-arrow, and
most others in the range 0-32. (In a terminfo entry designed for use
with ncurses, the high-half characters are obtained using this
attribute with an acsc string in which the second of each pair is a
high-half character.)
Giving wechochar an argument with its high bit set will produce the
corresponding high-half ASCII graphic (SVr4 curses also has this fea‐
ture but does not document it). A control-character argument, however,
will not typically produce the corresponding graphic; characters such
as CR, NL, FF and TAB are typically interpreted by the console driver
itself, and ESC will be interpreted as the leader of a control
sequence.
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.
The seven ACS symbols starting with ACS_S3 were not documented in any
publicly released System V. However, many publicly available terminfos
include acsc strings in which their key characters (pryz{|}) are embed‐
ded, and a second-hand list of their character descriptions has come to
light. The ACS-prefixed names for them were invented for ncurses(3X).
SEE ALSOcurses(3X), curs_attr(3X), curs_clear(3X), curs_inch(3X), curs_out‐
opts(3X), curs_refresh(3X), putc(3S).
curs_addch(3X)