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 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.
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. (To emit control characters liter-
ally, 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 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.
Line Graphics
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 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 successful completion, unless other-
wise 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 standard 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 oth-
ers 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 sec-
ond 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 feature 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 stan-
dard, Issue 4. The defaults specified for forms-drawing
characters apply in the POSIX locale.
The seven ACS symbols starting with ACS_S3 were not docu-
mented 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).
SEE ALSO
curses(3X) curs_attr(3X) curs_clear(3X) curs_inch(3X)
curs_outopts(3X) curs_refresh(3X) putc(3S).