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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 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 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 character 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 ORed
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_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 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 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 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 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 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
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).
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