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 appropriately 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 win-dow window
dow 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 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 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 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 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_BLOCK -------------------------------------------------ACS_BLOCK
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 successful completion, unless otherwise noted in the preceding
routine descriptions.
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.
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 ALSO
curses(3X), curs_attr(3X), curs_clear(3X), curs_inch(3X), curs_outopts(3X), curs_refresh(3X),
putc(3S).
curs_addch(3X)
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