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Manual Pages  — curs_add_wch


add_wch, wadd_wch, mvadd_wch, mvwadd_wch, echo_wchar, wecho_wchar - add a complex character and rendition to a curses window, then advance the cursor



#include <curses.h>

int add_wch( const cchar_t *wch );
int wadd_wch( WINDOW *win, const cchar_t *wch );
int mvadd_wch( int y, int x, const cchar_t *wch );
int mvwadd_wch( WINDOW *win, int y, int x, const cchar_t *wch );
int echo_wchar( const cchar_t *wch );
int wecho_wchar( WINDOW *win, const cchar_t *wch );


The add_wch, wadd_wch, mvadd_wch, and mvwadd_wch functions put the complex character wch into the given window at its current position, which is then advanced. These functions perform wrapping and special-character processing as follows:
» If wch refers to a spacing character, then any previous character at that location is removed. A new character specified by wch is placed at that location with rendition specified by wch. The cursor then advances to the next spacing character on the screen.
» If wch refers to a non-spacing character, all previous characters at that location are preserved. The non-spacing characters of wch are added to the spacing complex character, and the rendition specified by wch is ignored.
» If the character part of wch is a tab, newline, backspace or other control character, the window is updated and the cursor moves as if addch were called.
The echo_wchar function is functionally equivalent to a call to add_wch followed by a call to refresh. Similarly, the wecho_wchar is functionally equivalent to a call to wadd_wch followed by a call to wrefresh. 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 the *echo* functions instead of their equivalents.

Line Graphics

Like addch(3X), addch_wch accepts symbols which make it simple to draw lines and other frequently used special characters. These symbols correspond to the same VT100 line-drawing set as addch(3X).

WACS_BOARD0x2592#board of squares
WACS_BTEE0x2534+bottom tee
WACS_CKBOARD0x2592:checker board (stipple)
WACS_DARROW0x2193varrow pointing down
WACS_DEGREE0x00b0'degree symbol
WACS_HLINE0x2500-horizontal line
WACS_LANTERN0x2603#lantern symbol
WACS_LARROW0x2190<arrow pointing left
WACS_LLCORNER0x2514+lower left-hand corner
WACS_LRCORNER0x2518+lower right-hand corner
WACS_LTEE0x2524+left tee
WACS_PI0x03c0*greek pi
WACS_RARROW0x2192>arrow pointing right
WACS_RTEE0x251c+right tee
WACS_S10x23ba-scan line 1
WACS_S30x23bb-scan line 3
WACS_S70x23bc-scan line 7
WACS_S90x23bd_scan line 9
WACS_STERLING0x00a3fpound-sterling symbol
WACS_TTEE0x252c+top tee
WACS_UARROW0x2191^arrow pointing up
WACS_ULCORNER0x250c+upper left-hand corner
WACS_URCORNER0x2510+upper right-hand corner
WACS_VLINE0x2502|vertical line

The wide-character configuration of ncurses also defines symbols for thick- and double-lines:

WACS_T_LLCORNER0x2517+thick lower left corner
WACS_T_URCORNER0x2513+thick upper right corner
WACS_T_LRCORNER0x251b+thick lower right corner
WACS_T_LTEE0x252b+thick tee pointing right
WACS_T_RTEE0x2523+thick tee pointing left
WACS_T_BTEE0x253b+thick tee pointing up
WACS_T_TTEE0x2533+thick tee pointing down
WACS_T_HLINE0x2501-thick horizontal line
WACS_T_VLINE0x2503|thick vertical line
WACS_T_PLUS0x254b+thick large plus or crossover
WACS_D_ULCORNER0x2554+double upper left corner
WACS_D_LLCORNER0x255a+double lower left corner
WACS_D_URCORNER0x2557+double upper right corner
WACS_D_LRCORNER0x255d+double lower right corner
WACS_D_RTEE0x2563+double tee pointing left
WACS_D_LTEE0x2560+double tee pointing right
WACS_D_BTEE0x2569+double tee pointing up
WACS_D_TTEE0x2566+double tee pointing down
WACS_D_HLINE0x2550-double horizontal line
WACS_D_VLINE0x2551|double vertical line
WACS_D_PLUS0x256c+double large plus or crossover


All routines return the integer ERR upon failure and OK on success.

Functions with a "mv" prefix first perform a cursor movement using wmove, and return an error if the position is outside the window, or if the window pointer is null.


Note that add_wch, mvadd_wch, mvwadd_wch, and echo_wchar may be macros.


All of these functions are described in the XSI Curses standard, Issue 4. The defaults specified for line-drawing characters apply in the POSIX locale.

X/Open Curses makes it clear that the WACS_ symbols should be defined as a pointer to cchar_t data, e.g., in the discussion of border_set. A few implementations are problematic:
» NetBSD curses defines the symbols as a wchar_t within a cchar_t.
» HPUX curses equates some of the ACS_ symbols to the analogous WACS_ symbols as if the ACS_ symbols were wide characters. The misdefined symbols are the arrows and other symbols which are not used for line-drawing.
X/Open Curses does not define symbols for thick- or double-lines. SVr4 curses implementations defined their line-drawing symbols in terms of intermediate symbols. This implementation extends those symbols, providing new definitions which are not in the SVr4 implementations.


curses(3), curs_addch(3), curs_attr(3), curs_clear(3), curs_outopts(3), curs_refresh(3), putwc(3)

curs_add_wch (3X)

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