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man pages section 3: Curses Library Functions

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Updated: Thursday, June 13, 2019
 
 

echowchar(3CURSES)

Name

curs_addwch, addwch, waddwch, mvaddwch, mvwaddwch, echowchar, wechowchar - add a wchar_t character (with attributes) to a curses window and advance cursor

Synopsis

cc  [flag]... file... -lcurses [library]...
#include <curses.h>

int addwch(chtype wch);
int waddwch(WINDOW *win, chtype wch);
int mvaddwch(int y, int x, chtype wch);
int mvwaddwch(WINDOW *win, int y, int x, chtype wch);
int echowchar(chtype wch);
int wechowchar(WINDOW *win, chtype wch);

Description

The addwch(),waddwch(),mvaddwch(), and mvwaddwch() routines put the character wch, holding a wchar_t character, into the window at the current cursor position of the window and advance the position of the window cursor. Their function is similar to that of putwchar(3C) in the C multibyte library. At the right margin, an automatic newline is performed. At the bottom of the scrolling region, if scrollok is enabled, the scrolling region is scrolled up one line.

If wch is a tab, newline, or backspace, the cursor is moved appropriately within the window. A newline also does a clrtoeol(3CURSES) before moving. Tabs are considered to be at every eighth column. If wch is another control character, it is drawn in the ^X notation. Calling winwch(3CURSES) after adding a control character does not return the control character, but instead returns the representation of the control character.

Video attributes can be combined with a wchar_t character by OR-ing them into the parameter. This results in these attributes also being set. (The intent here is that text, including attributes, can be copied from one place to another using inwch() and addwch().) See standout(3CURSES), predefined video attribute constants.

The echowchar() and wechowchar() routines are functionally equivalent to a call to addwch() followed by a call to refresh(3CURSES), or a call to waddwch() followed by a call to wrefresh(3CURSES). The knowledge that only a single character is being output is taken into consideration and, for non-control characters, a considerable performance gain might 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 addwch() family. When variables are defined for the terminal, the A_ALTCHARSET bit is turned on. (See curs_attr(3CURSES)). Otherwise, the default character listed below is stored in the variable. The names chosen are consistent with the VT100 nomenclature.

Name
Default
Glyph 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_RARRROW
>
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

RETURN VALUE

All routines return the integer ERR upon failure and an integer value other than ERR upon successful completion, unless otherwise noted in the preceding routine descriptions.

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
MT-Level
Unsafe

See Also

winwch(3CURSES), refresh(3CURSES), clrtoeol(3CURSES), curs_attr(3CURSES), curs_inwch(3CURSES), curs_outopts(3CURSES), curses(3CURSES), standout(3CURSES), wrefresh(3CURSES), putwchar(3C), attributes(7)

Notes

The header file <curses.h> automatically includes the header files <stdio.h>, <unctrl.h> and <widec.h>.

Note that addwch(), mvaddwch(), mvwaddwch(), and echowchar() may be macros.

None of these routines can use the color attribute in chtype.