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curs_add_wch
Section: Miscellaneous Library Functions (3X)Updated:
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NAME
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 cursorSYNOPSIS
#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 );
DESCRIPTION
add_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.
echo_wchar
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).
| The wide-character configuration of ncurses also defines symbols | |||||||||
| l l l l | |||||||||
| _ _ _ _ | | ||||||||
| lw(1.5i) lw7 lw7 lw20. | |||||||||
| Name | Unicode | Default | Description | ||||||
| WACS_T_ULCORNER | |||||||||
| WACS_T_LLCORNER | 0x2517 | ||||||||
| WACS_T_URCORNER | 0x2513 | + | thick upper right corner | ||||||
| WACS_T_LRCORNER | 0x251b | + | thick lower right corner | | |||||
| WACS_T_LTEE | 0x252b | + | thick tee pointing right | | |||||
| WACS_T_RTEE | 0x2523 | + | thick tee pointing left | | |||||
| WACS_T_BTEE | 0x253b | + | thick tee pointing up | ||||||
| WACS_T_TTEE | 0x2533 | + | thick tee pointing down | ||||||
| WACS_T_HLINE | 0x2501 | - | thick horizontal line | | |||||
| WACS_T_VLINE | 0x2503 | | | thick vertical line | | |||||
| WACS_T_PLUS | |||||||||
| WACS_D_ULCORNER | 0x2554 | + | |||||||
| WACS_D_LLCORNER | 0x255a | ||||||||
| WACS_D_URCORNER | 0x2557 | ||||||||
| WACS_D_LRCORNER | 0x255d | ||||||||
| WACS_D_RTEE | 0x2563 | + | double tee pointing left | ||||||
| WACS_D_LTEE | 0x2560 | ||||||||
| WACS_D_BTEE | 0x2569 | + | double tee pointing up | | |||||
| 0x2566 | + | double tee pointing down | | ||||||
| WACS_D_HLINE | 0x2550 | - | double horizontal line | | |||||
| 0x2551 | | | double vertical line | | ||||||
| WACS_D_PLUS | 0x256c | + | double large plus or crossover | | |||||
RETURN VALUE
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.
NOTES
Note that add_wch, mvadd_wch, mvwadd_wch, and echo_wchar may be macros.
PORTABILITY
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.
SEE ALSO
curses(3X), curs_addch(3X), curs_attr(3X), curs_clear(3X), curs_outopts(3X), curs_refresh(3X), putwc(3)